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Sample records for part-time wearing esthetic

  1. Resistance to abrasion of extrinsic porcelain esthetic characterization techniques.

    Science.gov (United States)

    Chi, Woo J; Browning, William; Looney, Stephen; Mackert, J Rodway; Windhorn, Richard J; Rueggeberg, Frederick

    2017-01-01

    A novel esthetic porcelain characterization technique involves mixing an appropriate amount of ceramic colorants with clear, low-fusing porcelain (LFP), applying the mixture on the external surfaces, and firing the combined components onto the surface of restorations in a porcelain oven. This method may provide better esthetic qualities and toothbrush abrasion resistance compared to the conventional techniques of applying color-corrective porcelain colorants alone, or applying a clear glaze layer over the colorants. However, there is no scientific literature to support this claim. This research evaluated toothbrush abrasion resistance of a novel porcelain esthetic characterization technique by subjecting specimens to various durations of simulated toothbrush abrasion. The results were compared to those obtained using the conventional characterization techniques of colorant application only or colorant followed by placement of a clear over-glaze. Four experimental groups, all of which were a leucite reinforced ceramic of E TC1 (Vita A1) shade, were prepared and fired in a porcelain oven according to the manufacturer's instructions. Group S (stain only) was characterized by application of surface colorants to provide a definitive shade of Vita A3.5. Group GS (glaze over stain) was characterized by application of a layer of glaze over the existing colorant layer as used for Group S. Group SL (stain+LFP) was characterized by application of a mixture of colorants and clear low-fusing add-on porcelain to provide a definitive shade of Vita A3.5. Group C (Control) was used as a control without any surface characterization. The 4 groups were subjected to mechanical toothbrushing using a 1:1 water-to-toothpaste solution for a simulated duration of 32 years of clinical use. The amount of wear was measured at time intervals simulating every 4 years of toothbrushing. These parameters were evaluated longitudinally for all groups as well as compared at similar time points among

  2. Parameter Estimation of a Delay Time Model of Wearing Parts Based on Objective Data

    Directory of Open Access Journals (Sweden)

    Y. Tang

    2015-01-01

    Full Text Available The wearing parts of a system have a very high failure frequency, making it necessary to carry out continual functional inspections and maintenance to protect the system from unscheduled downtime. This allows for the collection of a large amount of maintenance data. Taking the unique characteristics of the wearing parts into consideration, we establish their respective delay time models in ideal inspection cases and nonideal inspection cases. The model parameters are estimated entirely using the collected maintenance data. Then, a likelihood function of all renewal events is derived based on their occurring probability functions, and the model parameters are calculated with the maximum likelihood function method, which is solved by the CRM. Finally, using two wearing parts from the oil and gas drilling industry as examples—the filter element and the blowout preventer rubber core—the parameters of the distribution function of the initial failure time and the delay time for each example are estimated, and their distribution functions are obtained. Such parameter estimation based on objective data will contribute to the optimization of the reasonable function inspection interval and will also provide some theoretical models to support the integrity management of equipment or systems.

  3. Psychometric properties of the Dutch version of the Orofacial Esthetic Scale (OES-NL) in dental patients with and without self-reported tooth wear

    NARCIS (Netherlands)

    Wetselaar, P.; Koutris, M.; Visscher, C.M.; Larsson, P.; John, M.T.; Lobbezoo, F.

    2015-01-01

    The aim of this study was to test the psychometric properties of the Dutch version of the Orofacial Esthetic Scale (OES) in dental patients with and without self-reported tooth wear. The English version of the OES was translated into Dutch, following established guidelines for cross-cultural

  4. CAD/CAM splints for the functional and esthetic evaluation of newly defined occlusal dimensions.

    Science.gov (United States)

    Edelhoff, Daniel; Schweiger, Josef; Prandtner, Otto; Trimpl, Johannes; Stimmelmayr, Michael; Güth, Jan-Frederik

    2017-01-01

    Pretreatment with occlusal splints is a crucial step in a structured treatment approach for a complex rehabilitation that changes the vertical dimension of occlusion. Meticulous patient compliance is one of the essential prerequisites for overall treatment success. However, patient compliance is all too often insufficient due to esthetic, phonetic, and functional limitations when using conventional occlusal splints in one arch. Modern production technologies now allow the use of tooth-colored occlusal splints made of polycarbonate, whose quality and material properties are quite distinct from those of conventionally manufactured splints made of transparent polymethyl methacrylate (PMMA). These materials, produced under standardized polymerization conditions, are extremely homogenous, which provides benefits such as a greater accuracy of fit by eliminating the polymerization shrinkage, greater long-term stability of shapes and shades, better biocompatibility, less wear, and a more favorable esthetic appearance. In addition, tooth-colored polycarbonate splints can be fabricated very thin without significantly increasing the fracture risk, thanks to the flexibility of the material. The improved wearing comfort combined with acceptable esthetics result in significantly improved patient compliance in terms of a "23-hour splint." By providing separate splints for the maxilla and mandible in the case of major alterations of the vertical dimension of occlusion, the esthetic and functional aspects defined by the wax-up can be completely transferred to the removable splints for a "test drive" by the patient, reversibly, and under realistic conditions. This dual-splint approach additionally facilitates segmental transfer into the definitive restoration.

  5. Application of charged particle activation for testing machine part wear

    International Nuclear Information System (INIS)

    Kosimova, M.; Tendera, P.

    1985-01-01

    The results of application of the charge particle activation method to investigate machine part wear are presented. Study of radionuclide activity and yield has been carried out at the U-120M isochronous cyclotron by means of the method of iron foil piles from 20 to 100 μm in thick. Protons and deuterons have been used. Wear measurement is based on determination of wear particle activity in a butyric medium. An example of the results of a bench test of activated piston rings and cylinder liner of the engine for trucks is given. The method of surface activation is shown to be acceptable for studying machine part wear under the regular service conditions, especially on the stage of the primary investigations and development, when sampling structural materials and estimating different lubricating oil applicability

  6. Esthetics in periodontics and implantology.

    Science.gov (United States)

    Zucchelli, Giovanni; Sharma, Praveen; Mounssif, Ilham

    2018-06-01

    Periodontal plastic surgery comprises an increasing part of clinical periodontology. Clinical trials have traditionally used professionals to judge esthetic outcome, and few studies have addressed patient needs and requests (true end points). Development of universally accepted and validated methods for professional esthetic assessment, together with standardized questionnaires for patient-perceived outcome, may help to provide better insights into the true needs and benefits of periodontal and implant-associated plastic surgery. In this volume of Periodontology 2000, experienced researchers and clinicians from different subdisciplines of periodontology evaluate: treatment of gingival recession with or without papilla elevation; clinical crown lengthening in the natural dentition and in prosthodontic preparative treatment; periodontal regeneration around natural teeth; and soft-tissue augmentation in edentulous areas. Similarly, experts in different areas of implant science address esthetic outcomes with single and multiple implant rehabilitation, alveolar ridge preservation, implant positioning and immediate implant placement in the esthetic zone. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Implant Therapy in the Esthetic Zone-Surgical Considerations

    Directory of Open Access Journals (Sweden)

    Marković Aleksa

    2016-07-01

    Full Text Available Implant placement in the esthetic zone is a complex procedure and requires a restoration-driven approach. Proper selection of patients and implant together with individual assessment of the risk of esthetic complications are very important. Correct 3D-implant positioning and sufficient bone volume should provide long-term esthetic and function. Esthetic region is a zone in which expectations and possibilities collide. Clinician should bring the important decision on the appropriate time of implant placement. Immediate implant placement is particularly challenging in the esthetic zone. Patient desire for reduced treatment time should be weighed against the possible risk factors. Protocol of immediate implant placement in conditions of unfavourable gingival biotypes, the lack of bone or soft tissue in patients with a high smile line lead to esthetic failure which is very important in the esthetic region.

  8. Evolution of esthetic considerations in orthodontics.

    Science.gov (United States)

    Turley, Patrick K

    2015-09-01

    The importance of facial esthetics to the practice of orthodontics has its origins at the beginning of our specialty. In 1900, Edward H. Angle believed that an esthetic or a "harmonious" face required a full complement of teeth, but many who came after him questioned this notion. In the 1930s, the development of cephalometrics laid the foundation for studying growth and development, treatment effects, facial forms, and esthetics. By the 1950s, the importance of diagnosing and planning treatment for an esthetic result was established, but the measurement of soft tissue variables was lacking, and this became an important area of research. In the 1970s, researchers were looking at the stability of hard tissue changes over time, and they were also interested in how the soft tissues change with age. Although the early studies of esthetics in orthodontic treatment focused on how clinicians viewed their patients, changing demographics and cultural attitudes led researchers to look more seriously at consumer preferences and the public's attitudes. Their findings--that consumers preferred fuller lips--led to a swing back toward nonextraction treatment. Expansion appliances and molar distalization techniques became popular, and surgical procedures to obtain more ideal esthetic results became more common. Since the 1990s, advances in computers and technology have allowed us to study, predict, and produce esthetic results previously thought unattainable. Today, more so than at any other time in our specialty, we have the ability to provide esthetic results to our patients. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  9. Color stability of esthetic coatings applied to nickel-titanium archwires

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Neiva Nunes do REGO

    Full Text Available Abstract Introduction Color stability is an important feature to be considered when using esthetic coated archwires. Objective To evaluate color changes on the surface of esthetic nickel-titanium archwires coated with Teflon (Ortho Organizers, USA or epoxy resin (Tecnident, Brazil after immersion in staining solution. Material and method Twelve 20-mm-long wire segments were used for each type of coating, which were mounted as two test specimens with a width of 7 mm each. The buccal surface of the archwires was evaluated for fluorescence and color measurements both at baseline and after immersion in a staining solution for 21 days using the VITA Easyshade® Compact spectrophotometer (Model DEASYC220. Differences in total color change according to coating type were compared using an independent samples t-test (p<0.05. The surface characteristics of as-received coated archwires were assessed using scanning electron microscopy. Result Color changes were observed on the esthetic coatings, with a significant difference between the two brands analyzed. Surface analysis revealed flaws such as wear, pitting, elevations, lack of material, granulation, grooves, cracks, and lack of standardization in the coating process in all as-received archwires, but flaws were less evident in epoxy-resin coatings. Conclusion The two esthetic coatings did not show color stability, but Teflon coatings showed a more intense color change than epoxy-resin coatings.

  10. Determination of rail wear and short-time wear measurements of rails applying radioisotopes

    International Nuclear Information System (INIS)

    Grohmann, H.D.

    1981-01-01

    An energetic model has been developed for calculating rail wear. Short-time wear tests on rails after surface activation and following activity measurements showed a good agreement with the calculated values

  11. Tool Wear Monitoring Using Time Series Analysis

    Science.gov (United States)

    Song, Dong Yeul; Ohara, Yasuhiro; Tamaki, Haruo; Suga, Masanobu

    A tool wear monitoring approach considering the nonlinear behavior of cutting mechanism caused by tool wear and/or localized chipping is proposed, and its effectiveness is verified through the cutting experiment and actual turning machining. Moreover, the variation in the surface roughness of the machined workpiece is also discussed using this approach. In this approach, the residual error between the actually measured vibration signal and the estimated signal obtained from the time series model corresponding to dynamic model of cutting is introduced as the feature of diagnosis. Consequently, it is found that the early tool wear state (i.e. flank wear under 40µm) can be monitored, and also the optimal tool exchange time and the tool wear state for actual turning machining can be judged by this change in the residual error. Moreover, the variation of surface roughness Pz in the range of 3 to 8µm can be estimated by the monitoring of the residual error.

  12. Impact of Advertising on Tampon Wear-time Practices.

    Science.gov (United States)

    Woeller, Kara E; Miller, Kenneth W; Robertson-Smith, Amy L; Bohman, Lisa C

    2015-01-01

    (1) To determine whether advertising nighttime tampon use for up to eight hours was understood to be consistent with label recommendations and (2) to determine whether television and print advertising with this message affected tampon wear times in adults and teens. (1) A comprehension study (online advertising and follow-up questionnaire) among women aged 14-49 years (300 per group) who viewed either the test or a control advertising message; (2) Diary-based surveys of tampon wear times performed prior to (n = 292 adults, 18-49 years, 74 teens, 12-17 years) and after (n = 287 adults, 104 teens) the launch of national advertising. Significantly more test message viewers than controls stated tampons should be worn less than or equal to eight hours (93.6% vs. 88.6%, respectively, P = 0.049). A directionally higher percentage of test message viewers said they would use a pad if sleeping longer than eight hours (52% vs. 42% of controls). Among the women who used tampons longer than eight hours when sleeping, 52% reported they would wake up and change compared with 45% of controls. No significant difference between baseline and follow-up diary surveys was found among teens or adults in various measures of tampon wear time (mean wear times; usage intervals from less than two hours to more than 10 hours; percentage of tampons used for more than or equal to eight hours; frequency of wearing at least one tampon more than eight hours). Advertising nighttime tampon wear for up to eight hours effectively communicated label recommendations but did not alter tampon wear times. The informational intervention had limited impact on established habits.

  13. On the Esthetic Value of Works of Art

    Directory of Open Access Journals (Sweden)

    Blagomir Papazov

    2017-03-01

    Full Text Available The study of the processes involved in the creation of a work of art has been the focus of numerous complex theories which continue to find new interpretations in an attempt to reflect the emerging innovative forms of visual arts. Theory and history of art are an ever-changing field of ideas and interpretations of the processes of art creation and discussions about the definition of what constitutes a „work of art“. Works of art have a special social significance as they are an integral part of the culture of a society. They reflect the esthetic and artistic values of the time in which they were created, and the style and changes it undergoes in time. The interpretation of a work of art has always been a kind of improvisation, which however requires esthetic empirical evidence and professional expertise in the respective type of art.

  14. How patient-selected colors for removable appliances are reflected in electronically tracked compliance (wear times and wear behavior).

    Science.gov (United States)

    Schott, Timm C; Menne, Dieter

    2018-03-27

    A broad spectrum of colors for removable appliances, intended to optimize acceptance of treatment and patient cooperation, have been available on the dental market for years. This is the first study to analyze how patient-selected colors are reflected in wear times and wear behavior of removable appliances. The study included 117 children (55 girls and 62 boys) who were treated with active removable plate or functional appliances. All patients were offered to choose from 11 different colors, which were pooled into six groups (black, blue, green, yellow, pink, red) for analysis, or to combine any two to four colors ("multicolored" group) for their appliances. All appliances featured a built-in microsensor (TheraMon; MC Technology, Hargelsberg, Austria) for objective wear-time tracking. Differences between wear times were analyzed using pairwise t tests and Tukey correction. The longest median wear times were recorded in the blue and green groups (≈11 h/d) and the shortest ones in the red and pink groups (≈9 h/d), but they were not significantly influenced by the patient-selected colors. The median wear times involved an age-related decrease by 0.56 h/y that was statistically significant ( P = .00005). No gender-specific patterns of wear behavior were observed. Patient-selected colors for removable appliances can presumably improve acceptance of treatment, but they are not associated with statistically significant improvements in wear time or wear behavior.

  15. Impact of Advertising on Tampon Wear-time Practices

    Directory of Open Access Journals (Sweden)

    Kara E. Woeller

    2015-01-01

    Full Text Available Objectives (1 To determine whether advertising nighttime tampon use for up to eight hours was understood to be consistent with label recommendations and (2 to determine whether television and print advertising with this message affected tampon wear times in adults and teens. Methods (1 A comprehension study (online advertising and follow-up questionnaire among women aged 14–49 years (300 per group who viewed either the test or a control advertising message; (2 Diary-based surveys of tampon wear times performed prior to ( n = 292 adults, 18–49 years, 74 teens, 12–17 years and after ( n = 287 adults, 104 teens the launch of national advertising. Results Significantly more test message viewers than controls stated tampons should be worn less than or equal to eight hours (93.6% vs. 88.6%, respectively, P = 0.049. A directionally higher percentage of test message viewers said they would use a pad if sleeping longer than eight hours (52% vs. 42% of controls. Among the women who used tampons longer than eight hours when sleeping, 52% reported they would wake up and change compared with 45% of controls. No significant difference between baseline and follow-up diary surveys was found among teens or adults in various measures of tampon wear time (mean wear times; usage intervals from less than two hours to more than 10 hours; percentage of tampons used for more than or equal to eight hours; frequency of wearing at least one tampon more than eight hours. Conclusions Advertising nighttime tampon wear for up to eight hours effectively communicated label recommendations but did not alter tampon wear times. The informational intervention had limited impact on established habits.

  16. Optimization of the wearing time for passive individual dosimeters

    International Nuclear Information System (INIS)

    Aleinikov, V.E.; )

    1998-01-01

    A cost-benefit equation was derived for the optimum wearing time of passive individual dosemeters. This equation was applied to the long-normal distribution of occupational individual doses. A plot of the optimum wearing time in dependence on the lower detection limit is reproduced. It is shown that the optimum wearing time depends on the dose distribution as well as on the quotient of the cost assigned to the unit collective dose, α, the cost of the dosemeter, C, and the lower detection limit, D. If the C/α ratio is infinitesimal, the optimum wearing time is directly proportional to the square root of the DL product (L is the dose limit) and inversely proportional to the average annual individual dose for the log-normal distribution. (P.A.)

  17. Complex technique for studying the machine part wear

    International Nuclear Information System (INIS)

    Grishko, V.A.; Zhushma, V.F.

    1981-01-01

    A technique to determine the wear of steel details rolling with sliding with circulatory lubrication is suggested. The functional diagram of the experimental device and structural diagrams of equipment to register the wear of tested samples and forming the lubricating layer between them, are considered. Results of testing three conples of disc samples and the data characterizing the dependence of sample wear on the value of contact stress are presented. The peculiarity of the device used is synchronous registering of the lubricating layer formation in the place of contact and detail mass loss in time which is realized correspondingly over discharge voltage on the lubricating layer and the intensity of radiation from detail wear products activated by neutrons. On the basis, of the investigation the conclusion is made that MEhF-1 oil has a greater antiwear effectiveness than the universal TAD-17 1 oil used presently [ru

  18. Esthetic Dentistry

    OpenAIRE

    McComb, D.

    1989-01-01

    The author of this article discusses the development of means to attach biologically acceptable polymers to tooth enamel, as well as the ongoing development of suitable reinforced plastics to provide esthetic improvement of patients' teeth. She describes a variety of esthetic dental problems and discusses their treatment.

  19. Esthetic evaluation of maxillary single-tooth implants in the esthetic zone

    Science.gov (United States)

    Cho, Hae-Lyung; Lee, Jae-Kwan; Um, Heung-Sik

    2010-01-01

    Purpose The aim of this study is to assess the influence exerted by the observer's dental specialization and compare patients' opinion with observers' opinion of the esthetics of maxillary single-tooth implants in the esthetic zone. Methods Forty-one adult patients, who were treated with a single implant in the esthetic zone, were enrolled in this study. Eight observers (2 periodontists, 2 prosthodontists, 2 orthodontists and 2 senior dental students) applied the pink esthetic score (PES)/white esthetic score (WES) to 41 implant-supported single restorations twice with an interval of 4 weeks. We used a visual analog scale (VAS) to assess the patient's satisfaction with the treatment outcome from an esthetic point of view. Results In the PES/WES, very good and moderate intraobserver agreements were noted between the first and second rating. The mean total PES/WES was 11.19 ± 3.59. The mean PES was 5.17 ± 2.29 and mean WES was 6.02 ± 1.96. In the total PES/WES, the difference between the groups was not significant. However, in the WES, the difference between the groups was significant and prosthodontists were found to have assigned poorer ratings than the other groups. Periodontists gave higher ratings than prosthodontists and senior dental students. Orthodontists were clearly more critical than the other observers. The statistical analysis revealed statistically significant correlation between patients' esthetic perception and dentists' perception of the anterior tooth. However, the correlation between the total PES/WES and the VAS score for the first premolar was not statistically significant. Conclusions The PES/WES is an objective tool in rating the esthetics of implant supported single crowns and adjacent soft tissues. Orthodontists were the most critical observers, while periodontists were more generous than other observers. The statistical analysis revealed a statistically significant correlation between patients' esthetic perception and dentists

  20. Ethics of esthetic dentistry

    DEFF Research Database (Denmark)

    Liebler, Michael; Devigus, Alessandro; Randall, Ros C

    2004-01-01

    Patient demand for esthetics has increased globally, and often for reasons of patient self-esteem. However, important ethical issues encompass treatment for purely esthetic reasons. Also, perceptions of what is esthetic differ among patients and clinicians. Therefore, the aim of this article...

  1. Orthodontics and esthetics of the face: from the "canons" of ancient times to contemporary pluralism. A critical review.

    Science.gov (United States)

    Ioannidou-Marathiotou, Ioulia; Papamanou, Despoina A; Papadopoulos, Moschos A

    2008-01-01

    Efforts to define facial esthetics and natural attraction using objective criteria go back in time. Nowadays, the abundance of available information, the evolution in our understanding, the intermeshing of the neurosciences and biology, as well as the potential of digital technology, have provided new elements for the objective definition of esthetics and shaped new perceptions and perspectives. The aim of this paper is to attempt a critical analysis from a clinical orthodontic perspective of the conventional methods assessing facial beauty as well as of the trends and viewpoints that form today's concept of an esthetically ideal face, based on a historical review from ancient times to the 21st century. It appears that the "beauty standards" formulated artificially by the mass media and the internet remain a challenge for the orthodontist, who is called upon to explore the aspirations, motives and expectations of patients in order to be able to contribute in improving their social status and quality of life.

  2. Evaluation of the influence of implant placement timing on the esthetic outcomes of single tooth implant treatment in the anterior maxilla: A retrospective study.

    Science.gov (United States)

    Arora, Himanshu; Ivanovski, Saso

    2018-05-15

    The purpose of this retrospective study was to investigate the influence of implant placement timing on the esthetic outcomes for single implants in the anterior maxilla. One hundred and ten patients (48 males; 62 females) who received a single-tooth implant after extraction either immediately (Type 1); after 4-8 weeks (Type 2); after 8-16 weeks (Type 3); or more than 16 weeks (Type 4) were evaluated in terms of esthetic outcomes after a mean post-placement interval of 26.3 months (range 12-116). Esthetic outcomes were measured using the Pink and White Esthetic Score (PES; WES). Stepwise regression analysis was performed to analyze the effect of timing of placement, as well as patient demographics and other clinical parameters on the esthetic outcomes. No statistically significantly differences in PES were found between the various treatment modalities with Type 1 implants (n = 33) scoring 10.58 ± 1.65 (median: 11), followed by 10.36 ± 2.09 (median: 10.5), 9.68 ± 2.43 (median: 10), and 9.63 ± 2.21 (median: 10) for Type 2 (n = 14), Type 3 (n = 19), and Type 4 (n = 44), respectively. For immediate implants, a trend towards better esthetic outcomes was observed when implant placement was done flaplessly in cases with intact buccal bone (Type 1A, median PES 11) as compared to cases with partial/complete missing buccal plates where a flap was raised (Type 1B, median PES 10). Overall, the only parameter that influenced esthetic outcomes (as measured by PES) was gender, with females having significantly superior results. The median WES was 8 and 96% of the crowns were deemed esthetically acceptable, with crowns placed by specialist prosthodontists yielding higher scores than those placed by general practitioners. Single tooth implants in the anterior maxilla showed satisfactory outcomes when measured with objective esthetic criteria. Timing of implant placement did not significantly influence the esthetic outcomes, although a trend

  3. Association between Severity of Tooth Wear and Dentinal Hypersensitivity

    Directory of Open Access Journals (Sweden)

    Ashok Ayer

    2016-11-01

    Full Text Available Background & Objectives: Tooth wear (attrition, abrasion, erosion, and abfraction is perceived globally as ever increasing problem. Several outcome of the tooth wear are hypersensitivity, esthetic problems, functional impairment, annoyance to the patient, and fracture of the tooth. Among these, the measurable and more commonly reported outcome is hypersensitivity to stimuli. Although dentin hypersensitivity is a common clinical condition and is generally reported by the patient after experiencing a sharp, short pain caused by one of the several different external stimuli, it is often inadequately understood. None of the scientific literature available till date attempted to establish the relationship between tooth wear and dentin hypersensitivity which could be a key factor in monitoring those patients.  The aim of the study was to estimate the association between severity of teeth wear and sensitivity in the patients with reported dentinal hypersensitivity.Materials & Methods: Fifty patients with dentin hypersensitivity were investigated for tooth wear. Tooth wear measured using exact tooth wear index and level of sensitivity to stimuli was recorded using a numerical rating scale. Results: Enamel wear at cervical region of teeth showed a positive correlation (p=.010, similarly, dentin wear at cervical region of teeth showed positive correlation and significant association (p<.001 with dentinal hypersensitivity.Conclusion: The observation supports a significant association between severities of tooth surface wear and dentinal hypersensitivity.

  4. Amelogenesis Imperfecta: A Non-Invasive Approach to Improve Esthetics in Young Patients. Report of Two Cases.

    Science.gov (United States)

    Cagetti, Maria Grazia; Cattaneo, Stefano; Hu, Ye Qing; Campus, Guglielmo

    Objective-Evaluate esthetic and functional efficacy of infiltrant resin (Icon, DMG, Hamburg, Germany) in Amelogenesis Imperfecta's treatment. Two adolescent patients, G.S. (13 years old) and C.M. (15 years old), affected by the hypomaturation type of Amelogenesis Imperfecta, were treated with Icon resin and were followed for twelve months. Treated teeth show an excellent aesthetical result immediately after the resin application, effect that lasts in the long-term (six and twelve months follow-up examinations); the dental wear's progression seems to be clinically arrested. Resin infiltration has proven to be a minimal invasive treatment for dental discoloration, less aggressive than conventional procedures. This approach might be recommended for a stable esthetical improvement in moderate AI's lesions especially in children and adolescents.

  5. An adaptive observer for on-line tool wear estimation in turning, Part I: Theory

    Science.gov (United States)

    Danai, Kourosh; Ulsoy, A. Galip

    1987-04-01

    On-line sensing of tool wear has been a long-standing goal of the manufacturing engineering community. In the absence of any reliable on-line tool wear sensors, a new model-based approach for tool wear estimation has been proposed. This approach is an adaptive observer, based on force measurement, which uses both parameter and state estimation techniques. The design of the adaptive observer is based upon a dynamic state model of tool wear in turning. This paper (Part I) presents the model, and explains its use as the basis for the adaptive observer design. This model uses flank wear and crater wear as state variables, feed as the input, and the cutting force as the output. The suitability of the model as the basis for adaptive observation is also verified. The implementation of the adaptive observer requires the design of a state observer and a parameter estimator. To obtain the model parameters for tuning the adaptive observer procedures for linearisation of the non-linear model are specified. The implementation of the adaptive observer in turning and experimental results are presented in a companion paper (Part II).

  6. A comparison between indirect and objective wear-time assessment of removable orthodontic appliances.

    Science.gov (United States)

    Schott, Timm C; Meyer-Gutknecht, Hannes; Mayer, Nicolai; Weber, Joachim; Weimer, Katja

    2017-04-01

    Patients do not always adhere to the wear times prescribed for removable orthodontic appliances. We evaluated the validity and usability of indirect wear-time assessment methods by comparing wear-time estimates with microelectronically measured wear times in patients with removable orthodontic appliances. Wear times of 33 expansion plates, 34 functional appliances, and 42 retention plates of patients aged 6-20 years (12.3±2.9 years, 50.5% female) were indirectly determined by practitioners using a questionnaire assessing five parameters on a 5-point Likert scale: appliance handling, appliance appearance, bite shift, tooth movement, and appliance fit. The perceived difficulty in assessing each parameter was rated. Actual wear times were evaluated with microelectronic sensors in the appliances. Regression analyses revealed that practitioners' decisions about wear times varied depending on the type of appliance and criteria used, with only one standard criterion best predicting estimated wear time for each appliance. Different standard criteria were better predictors of measured wear time: 22.3% of wear-time variability was explained by expansion plate appearance, 31.2% by functional appliance handling, and 18.8% by retainer fitting. However, practitioners rated the difficulty of assessment in most cases as 'easy'. The study was not double blinded for technical reasons, and practitioners may have considered the evaluation criteria more carefully than in normal daily practice. Practitioners' decisions about wear times based on standard criteria strongly vary depending on the type of appliance and criteria used. © The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com

  7. Wear rate quantifying in real-time using the charged particle surface activation

    Science.gov (United States)

    Alexandreanu, B.; Popa-Simil, L.; Voiculescu, D.; Racolta, P. M.

    1997-02-01

    Surface activation, commonly known as Thin Layer Activation (TLA), is currently employed in over 30 accelerator laboratories around the world for wear and/or corrosion monitoring in industrial plants [1-6]. TLA was primarily designed and developed to meet requirements of potential industrial partners, in order to transfer this technique from research to industry. The method consists of accelerated ion bombardment of a surface of interest, e.g., a machine part subjected to wear. Loss of material owing to wear, erosive corrosion or abrasion is characterized by monitoring the resultant changes in radioactivity. In principle, depending upon the case at hand, one may choose to measure either the remnant activity of the component of interest or to monitor the activity of the debris. For applications of the second type, especially when a lubricating agent is involved, dedicated installations have been constructed and adapted to an engine or a tribological testing stand in order to assure oil circulation around an externally placed detection gauge. This way, the wear particles suspended in the lubricant can be detected and the material loss rates quantified in real time. Moreover, in specific cases, such as the one presented in this paper, remnant activity measurements prove to be useful tools for complementary results. This paper provides a detailed presentation of such a case: in situ resistance-to-wear testing of two types of piston rings.

  8. Esthetic Education in Soviet Schools.

    Science.gov (United States)

    Soviet Education, 1980

    1980-01-01

    This issue of Soviet Education examines esthetic education in Soviet schools, including ways of raising the level of esthetic education, the factor of labor, research on the relationship between the atheistic and esthetic education, ways of amplifying interrelationship between theory and practice in teacher education and psychological principles…

  9. Applicability of out-of-pile fretting wear tests to in-reactor fretting wear-induced failure time prediction

    Science.gov (United States)

    Kim, Kyu-Tae

    2013-02-01

    In order to investigate whether or not the grid-to-rod fretting wear-induced fuel failure will occur for newly developed spacer grid spring designs for the fuel lifetime, out-of-pile fretting wear tests with one or two fuel assemblies are to be performed. In this study, the out-of-pile fretting wear tests were performed in order to compare the potential for wear-induced fuel failure in two newly-developed, Korean PWR spacer grid designs. Lasting 20 days, the tests simulated maximum grid-to-rod gap conditions and the worst flow induced vibration effects that might take place over the fuel life time. The fuel rod perforation times calculated from the out-of-pile tests are greater than 1933 days for 2 μm oxidized fuel rods with a 100 μm grid-to-rod gap, whereas those estimated from in-reactor fretting wear failure database may be about in the range of between 60 and 100 days. This large discrepancy in fuel rod perforation may occur due to irradiation-induced cladding oxide microstructure changes on the one hand and a temperature gradient-induced hydrogen content profile across the cladding metal region on the other hand, which may accelerate brittleness in the grid-contacting cladding oxide and metal regions during the reactor operation. A three-phase grid-to-rod fretting wear model is proposed to simulate in-reactor fretting wear progress into the cladding, considering the microstructure changes of the cladding oxide and the hydrogen content profile across the cladding metal region combined with the temperature gradient. The out-of-pile tests cannot be directly applicable to the prediction of in-reactor fretting wear-induced cladding perforations but they can be used only for evaluating a relative wear resistance of one grid design against the other grid design.

  10. Validation of the prosthetic esthetic index

    DEFF Research Database (Denmark)

    Özhayat, Esben B; Dannemand, Katrine

    2014-01-01

    OBJECTIVES: In order to diagnose impaired esthetics and evaluate treatments for these, it is crucial to evaluate all aspects of oral and prosthetic esthetics. No professionally administered index currently exists that sufficiently encompasses comprehensive prosthetic esthetics. This study aimed...... to validate a new comprehensive index, the Prosthetic Esthetic Index (PEI), for professional evaluation of esthetics in prosthodontic patients. MATERIAL AND METHODS: The content, criterion, and construct validity; the test-retest, inter-rater, and internal consistency reliability; and the sensitivity...... furthermore distinguish between participants and controls, indicating sufficient sensitivity. CONCLUSION: The PEI is considered a valid and reliable instrument involving sufficient aspects for assessment of the professionally evaluated esthetics in prosthodontic patients. CLINICAL RELEVANCE...

  11. [Experts consensus of dental esthetic photography].

    Science.gov (United States)

    2017-05-09

    Clinical photography in esthetic dentistry is an essential skill in clinical practice. It is widely applied clinically in multiple fields related to esthetic dentistry. Society of Esthetic Dentistry of Chinese Stomatological Association established a consensus for clinical photography and standards for images in esthetic dentistry in order to standardize domestic dental practitioners' procedure, and meet the demands of diagnosis and design in modern esthetic dentistry. It was also developed to facilitate domestic and international academic communication. Sixteen commonly used images in practice, which are of apparent importance in guiding esthetic analysis, design and implementation, are proposed in the standards. This consensus states the clinical significance of these images and the standard protocol of acquiring them.

  12. Dental esthetic satisfaction, received and desired dental treatments for improvement of esthetics.

    Science.gov (United States)

    Akarslan, Zühre Zafersoy; Sadik, Burak; Erten, Hüya; Karabulut, Erdem

    2009-01-01

    The purposes of this research were to investigate factors influencing patients' satisfaction with their present dental esthetic, received previous dental treatments on anterior teeth and basic treatments that they wanted to undergo to improve their dental appearance. A total of 1014 patients who attended a dental school in a major city in Turkey participated in the study. The participants were surveyed with a questionnaire containing questions about gender, age, education level, self-reported tooth appearance, received previous dental treatments on anterior teeth and desired basic esthetic dental treatments. Statistical analysis of the verifying data was made with descriptive statistics, chi2 test and multiple logistic regression analyses. According to the analyses of the verifying data, 55.1% of the patients were dissatisfied with the color of their teeth, 42.7% with dental appearance, 29.9% with crowding of anterior teeth, 23.3% were hiding teeth while smiling, 16.1% had non-esthetic restorations and 11.9% thought that their anterior teeth were protruding. Esthetic restoration was found to be the most-performed treatment recently (29.0%) and whitening of teeth was the most-desired dental treatment (49.0%). Gender, age and education level had an effect on satisfaction and received previous and desired dental treatments for improvement of esthetics. Many of the Turkish patients surveyed in the study were dissatisfied and desired the improvement of dental esthetics. Therefore, dentists should consider this as an important dimension in their practice.

  13. 10 commandments of smile esthetics

    Science.gov (United States)

    Machado, Andre Wilson

    2014-01-01

    The search for esthetic treatment has persisted in the routine of dental professionals. Following this trend, dental patients have sought treatment with the primary aim of improving smile esthetics. The aim of this article is to present a protocol to assess patient's smile: The 10 Commandments of smile esthetics. PMID:25279532

  14. A STUDY OF ESTHETIC JUDGMENT.

    Science.gov (United States)

    CHILD, IRVIN L.

    THE ABILITY OF COLLEGE STUDENTS TO RECOGNIZE DEGREES OF ESTHETIC MERIT IN OBJECTS OF ART WAS STUDIED. THE OBJECTIVE WAS TO DETERMINE BY EXPERIMENTATION SOME OF THE FACTORS WHICH MAY BE IMPORTANT IN THE DEVELOPMENT OF ESTHETIC JUDGMENT. A SAMPLE OF MALE COLLEGE STUDENTS WAS GIVEN SEVERAL TESTS OF ESTHETIC JUDGMENT. FROM THESE SUBJECTS WERE CHOSEN…

  15. Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets

    Directory of Open Access Journals (Sweden)

    M S Kannan

    2015-01-01

    Full Text Available Aim: The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope study of the Brackets after Frictional evaluation. Materials and Methods: Two types of self-ligating esthetic brackets, Damon clear (Ormco made of fully ceramic and Opal (Ultradent Products, USA and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek and Damon 3 (Ormco both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot. Results: The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets. For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05 than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets generated smaller amount of frictional forces when compared with Damon clear and

  16. Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets.

    Science.gov (United States)

    Kannan, M S; Murali, R V; Kishorekumar, S; Gnanashanmugam, K; Jayanth, V

    2015-04-01

    The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope) study of the Brackets after Frictional evaluation. Two types of self-ligating esthetic brackets, Damon clear (Ormco) made of fully ceramic and Opal (Ultradent Products, USA) and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek) and Damon 3 (Ormco) both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA) and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot. The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets). For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05) than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets) which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets) generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets) generated smaller amount of frictional forces when compared with Damon clear and relatively higher amount of frictional forces

  17. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  18. Peri-implant esthetics assessment and management

    Science.gov (United States)

    Balasubramaniam, Aarthi S.; Raja, Sunitha V.; Thomas, Libby John

    2013-01-01

    Providing an esthetic restoration in the anterior region of the mouth has been the basis of peri-implant esthetics. To achieve optimal esthetics, in implant supported restorations, various patient and tooth related factors have to be taken into consideration. Peri-implant plastic surgery has been adopted to improve the soft tissue and hard tissue profiles, during and after implant placement. The various factors and the procedures related to enhancement of peri-implant esthetics have been discussed in this review article. PMID:23878557

  19. Single-tooth implant restorations in the esthetic zone--contemporary concepts for optimization and maintenance of soft tissue esthetics in the replacement of failing teeth in compromised sites.

    Science.gov (United States)

    Mankoo, Tidu

    2007-01-01

    In recent years, implant dentistry has undergone a profound shift in emphasis. The focus evolved first from a surgically driven approach to a prosthetically driven approach and now to a more biologically driven approach with the goal of optimizing and maintaining esthetics. While traditional implant protocols are well established for management of implants placed in healed edentulous sites, the data available offer little clarity on the factors and procedures for long-term esthetic success, particularly in terms of maintained stable soft tissue outcomes around implant restorations in the esthetic zone. Unfortunately, the 90%+ success rates indicated in most studies of dental implant systems today do not represent the success of the esthetic outcome. This has created a demand--certainly among clinicians in private practice focused on the ongoing maintenance of esthetic outcomes--for clear treatment protocols to achieve esthetic results that are not only predictable and consistent but that can withstand the test of time.

  20. The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2015-09-01

    Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

  1. [Diagnossis and treatment of complicated anterior teeth esthetic defects by combination of whole-process digital esthetic rehabilitation with periodontic surgery].

    Science.gov (United States)

    Li, Z; Liu, Y S; Ye, H Q; Liu, Y S; Hu, W J; Zhou, Y S

    2017-02-18

    To explore a new method of whole-process digital esthetic prosthodontic rehabilitation combined with periodontic surgery for complicated anterior teeth esthetic defects accompanied by soft tissue morphology, to provide an alternative choice for solving this problem under the guidance of three-dimensional (3D) printing digital dental model and surgical guide, thus completing periodontic surgery and digital esthetic rehabilitation of anterior teeth. In this study, 12 patients with complicated esthetic problems accompanied by soft tissue morphology in their anterior teeth were included. The dentition and facial images were obtained by intra-oral scanning and three-dimensional (3D) facial scanning and then calibrated. Two esthetic designs and prosthodontic outcome predictions were created by computer aided design /computer aided manufacturing (CAD/CAM) software combined with digital photography, including consideration of white esthetics and comprehensive consideration of pink-white esthetics. The predictive design of prostheses and the facial appearances of the two designs were evaluated by the patients. If the patients chose the design of comprehensive consideration of pink-white esthetics, they would choose whether they would receive periodontic surgery before esthetic rehabilitation. The dentition design cast of those who chose periodontic surgery would be 3D printed for the guide of periodontic surgery accordingly. In light of the two digital designs based on intra-oral scanning, facing scanning and digital photography, the satisfaction rate of the patients was significantly higher for the comprehensive consideration of pink-white esthetic design (Pesthetic rehabilitation. The 3D printed digital dental model and surgical guide provided significant instructions for periodontic surgery, and achieved success transfer from digital design to clinical application. The prostheses were fabricated by CAD/CAM, thus realizing the whole-process digital esthetic rehabilitation

  2. End points and assessments in esthetic dental treatment.

    Science.gov (United States)

    Ishida, Yuichi; Fujimoto, Keiko; Higaki, Nobuaki; Goto, Takaharu; Ichikawa, Tetsuo

    2015-10-01

    There are two key considerations for successful esthetic dental treatments. This article systematically describes the two key considerations: the end points of esthetic dental treatments and assessments of esthetic outcomes, which are also important for acquiring clinical skill in esthetic dental treatments. The end point and assessment of esthetic dental treatment were discussed through literature reviews and clinical practices. Before designing a treatment plan, the end point of dental treatment should be established. The section entitled "End point of esthetic dental treatment" discusses treatments for maxillary anterior teeth and the restoration of facial profile with prostheses. The process of assessing treatment outcomes entitled "Assessments of esthetic dental treatment" discusses objective and subjective evaluation methods. Practitioners should reach an agreement regarding desired end points with patients through medical interviews, and continuing improvements and developments of esthetic assessments are required to raise the therapeutic level of esthetic dental treatments. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  3. Soft Tissue Esthetics in Implant Dentistry

    Directory of Open Access Journals (Sweden)

    Rakesh V. Somanathan

    2007-01-01

    Full Text Available Dental implants have been considered to be a successful treatment modality. Recently, achieving a good osseointegration is not the ultimate goal for the restorative dentist. Successful implant treatment demands the best gingival esthetic success along with stability and function of the implant. This study was performed to obtain answers to some controversial points pertaining to esthetics and function of implants in maxilla. Immediate flapless implantation into the extraction sockets in maxillary anterior zone is an emerging treatment option in dentistry- the esthetic success of which was in debate for long. The proposed study compared the esthetic success of immediate flapless implants (ILA, to immediate implants with the need for flap (ILB and, delayed implants (DSL in single tooth restorations, in the anterior region of the maxilla. The other aim of the study was to find out if any relation exists between the interproximal crestal bone height and papilla height. Analysis was done irrespective of treatment procedure in the same study group using periodontal sounding and radiographs to find out the relation. From the study involving 106 participants, including 21 ILA, 22 ILB and 63 DSL cases, we received highest papillary index score of 2.6 average from group ILA, followed by ILB and DSL, after 3 months of prosthetic loading. From the periodontal sounding and radiographic study it was evident that, when the distance between the base of the contact point of crowns and height of interproximal bone was less than 5, the papilla was present 100 % of the time, but when the distance increased to 6 and more than 7 mm, the papilla was present only 46.5 and 24 percentage of the time respectively.

  4. Responsiveness of the Prosthetic Esthetic Scale

    DEFF Research Database (Denmark)

    Øzhayat, Esben Boeskov

    2017-01-01

    Objectives The aim of the study was to evaluate the responsiveness of the Prosthetic Esthetic Index (PEI) in a population who received prosthetic replacements. Materials and methods Fifty-seven patients who received prosthetic replacement of at least one tooth by means of fixed or removable...... prosthesis were professionally esthetically evaluated using the PEI and the Dental Aesthetic Index (DAI) before and after treatment. The participants further evaluated their oral esthetics using the Oral Health Impact Profile Aesthetic (OHIP-Aes) and Orofacial Esthetic Index (OES). Responsiveness......-Aes and OES scores. The PEI was more consistent in responsiveness than the DAI. Conclusions The PEI shows sufficient responsiveness for use in longitudinal studies and for use as a follow-up measure in clinical practice. Clinical relevance The PEI can in a standardized manner monitor and document esthetic...

  5. THE COURSE IN TESTING THE WEARING OUT OF MUD PUMPS PARTS

    Directory of Open Access Journals (Sweden)

    Davorin Matanović

    1989-12-01

    Full Text Available Piston and cylinder are such parts in the mud pumps which cause the greatest expences due to the work stoppage of drilling rig. To reduce so caused expences it is necessary to produce spare parts of better quality. In determining the abrasion wear resistance for chosen materials, so called dry sand/rubber wheel abrasion test as an ASTM standard has been used (the paper is published in Croatian.

  6. The peri-implant esthetics: An unforgettable entity

    Science.gov (United States)

    Dhir, Sangeeta

    2011-01-01

    Esthetic demands in today's world of dentistry are scaling new heights, and are driven by the zest to look beautiful. The soft tissue esthetics around implants is the foci of attention, which, if failed to meet, leads to unacceptable esthetic failure. The aim of this article is to give a brief overview of the various vital parameters influencing the esthetics governing the peri-implant area. PMID:21976830

  7. Minimally invasive esthetic ridge preservation with growth-factor enhanced bone matrix.

    Science.gov (United States)

    Nevins, Marc L; Said, Sherif

    2017-12-28

    Extraction socket preservation procedures are critical to successful esthetic implant therapy. Conventional surgical approaches are technique sensitive and often result in alteration of the soft tissue architecture, which then requires additional corrective surgical procedures. This case series report presents the ability of flapless surgical techniques combined with a growth factor-enhanced bone matrix to provide esthetic ridge preservation at the time of extraction for compromised sockets. When considering esthetic dental implant therapy, preservation, or further enhancement of the available tissue support at the time of tooth extraction may provide an improved esthetic outcome with reduced postoperative sequelae and decreased treatment duration. Advances in minimally invasive surgical techniques combined with recombinant growth factor technology offer an alternative for bone reconstruction while maintaining the gingival architecture for enhanced esthetic outcome. The combination of freeze-dried bone allograft (FDBA) and rhPDGF-BB (platelet-derived growth factor-BB) provides a growth-factor enhanced matrix to induce bone and soft tissue healing. The use of a growth-factor enhanced matrix is an option for minimally invasive ridge preservation procedures for sites with advanced bone loss. Further studies including randomized clinical trials are needed to better understand the extent and limits of these procedures. The use of minimally invasive techniques with growth factors for esthetic ridge preservation reduces patient morbidity associated with more invasive approaches and increases the predictability for enhanced patient outcomes. By reducing the need for autogenous bone grafts the use of this technology is favorable for patient acceptance and ease of treatment process for esthetic dental implant therapy. © 2017 Wiley Periodicals, Inc.

  8. Impact of digital prosthodontic planning on dental esthetics: Biometric analysis of esthetic parameters.

    Science.gov (United States)

    Abduo, Jaafar; Bennamoun, Mohammed; Tennant, Marc; McGeachie, John

    2016-01-01

    Improving dental esthetics is a main objective of prosthodontic treatment. Recently, digital diagnostic waxing has been proposed as an alternative to conventional diagnostic waxing; however, the impact on esthetics has not been evaluated. The purpose of this study was to evaluate the impact of diagnostic waxing on biometric esthetic variables and to compare the esthetic outcome achieved by digital waxing with conventional waxing. Three biometric variables were evaluated: perceived frontal proportion (PFP), width/height (W:H) ratio, and symmetry. Maxillary casts of 13 patients were collected. All of them had maxillary anterior teeth that required prosthodontic treatment. Two forms of diagnostic waxing were executed: conventional and digital waxing. Measurements of the esthetic variables were conducted digitally. For the PFP, a frontal image was made and the width of each tooth was measured. Subsequently, the PFP values of the lateral incisor to central incisor and of the canine to central incisor were calculated. In addition, the height and width of each tooth was measured to calculate the W:H ratio. Using the previous measurements, the symmetry between the right and left sides was determined. No consistent or recurrent PFP was detected for any cast. The diagnostic waxing did not alter the PFP of the pretreatment casts. The diagnostic waxing had restored the W:H ratio to what is assumed to be a natural ratio. An improvement in symmetry was detected after the diagnostic waxing and was more prominent after the digital waxing. However, no significant difference was found between the 2 diagnostic waxing methods. The 2 diagnostic waxing methods influenced the esthetic variables of the anterior maxillary teeth and yielded similar outcomes. Digital waxing appears to be a reasonable alternative, but further investigations are needed to ensure its practicality. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights

  9. Black triangle dilemma and its management in esthetic dentistry.

    Science.gov (United States)

    Singh, Vijendra P; Uppoor, Ashita S; Nayak, Dilip G; Shah, Dipen

    2013-05-01

    In recent years, clinician and dentist's esthetic demand in dentistry have increased rapidly, driven by an enhanced awareness of beauty and esthetics. The ultimate goal in modern restorative dentistry is to achieve "white" and "pink" esthetics in esthetically important zones. "White esthetics" is the natural dentition or the restoration of dental hard tissues with suitable materials. "Pink esthetics" refers to the surrounding soft-tissues, which includes the interdental papilla and gingiva that can enhance or diminish the esthetic result. Reconstruction of the lost interdental papilla is one of the most challenging and least predictable problems. Restoration and maintenance of these tissues with adequate surgical and prosthetic techniques are a real challenge in modern esthetic dentistry. Treatment of marginal tissue recession, excessive gingival display, deficient ridges, ridge collapse, and esthetic defects around teeth and implants are some of the esthetic problems associated with the interdental papilla that have to be corrected in todays scenario which has been discussed in this review.

  10. Tracer techniques for the investigation of wear mechanisms in coated or surface-treated machine parts

    International Nuclear Information System (INIS)

    Goedecke, T.; Grosch, J.

    1990-01-01

    Tracer techniques allow wear measurement down to rates of only some μg/h, and these measurements can be done continuously within an inspection test run, not requiring dismantling of the parts to be examined. The measurements revealed the materials pair of a chilled cast iron camshaft and a hard metal coated rocker arm to be superior in terms of wear behaviour over the materials pair of a malleable cast iron camshaft with induction hardening and a rocker arm with hard chromium plating. The total wear of a chilled cast iron camshaft was measured to be approx. 90% less than that of the malleable cast iron camshaft, under equal loading conditions. With the rocker arms, this ratio is approx. 1:3. Another disadvantage of the latter pair is the overall wear ratio of 19:1. The best wear resistance was measured with a TiN-coated rocker arm combined with a chilled cast iron camshaft. (orig./MM) [de

  11. Patient's Perception on the Esthetic Outcome of Anterior Fixed Prosthetic Treatment.

    Science.gov (United States)

    Alshiddi, Ibraheem F; BinSaleh, Saad M; Alhawas, Yasser

    2015-11-01

    Patient's perception to the esthetic result of the treatment received can be different from a dentist opinion. Understanding patient's opinion, demand and expectation is part of successful treatment procedure. The purpose of this study was to investigate patient's opinion about the esthetic result of the fixed prosthetic treatment received in upper anterior teeth. About 90 volunteer subjects, 58 males and 32 females were given a self-evaluation questionnaire with 11 questions to respond as Yes or No. The questions regarded the esthetic result of a fixed prosthodontic treatment received for their upper anterior teeth. The same questioner was completed for each subject by three clinicians through clinical photographs for different views of subject's smile. Agreement between patients and clinicians was calculated for all subjects to evaluate patient's perception to their esthetic results. An agreement of 47.8 to 72.2% was observed between patients and clinicians, and the average agreement was 53.64 to 60%. The highest agreement was related to satisfaction with the color of the crown and/or bridge margin while the least agreement was related to the satisfaction with the natural looking of the restoration. There was variability in the agreement between the patients and the dentists with the satisfaction of the esthetic result of anterior restoration. Factor, such as gender, age and educational level may affect the results of the agreement.

  12. Three-dimensional esthetic analysis in treatment planning for implant-supported fixed prosthesis in the edentulous maxilla: review of the esthetics literature.

    Science.gov (United States)

    Bidra, Avinash S

    2011-08-01

    Fixed implant-supported prosthesis for the edentulous maxilla has gained tremendous popularity over the years. Multiple prosthetic designs have been introduced in order to accommodate a gamut of clinical situations. Irrespective of the design, it is paramount that the esthetics imparted by the prosthesis be uncompromised. Though esthetics is subjective, a common ground exists where all its fundamental principles converge. This article reviews pertinent dental and facial esthetics literature for application of various esthetic concepts involved in diagnosis and treatment planning for an implant-supported fixed prosthesis in the edentulous maxilla. Three-dimensional esthetic analysis involves assessment of various esthetic parameters in superior-inferior, medial-lateral, and anterior-posterior dimensions. The impact of various esthetic parameters such as facial forms, facial profiles, maxillary teeth positions, maxillary teeth proportions, smile lines, lip support, gingival display, facial midline, dental midline, horizontal cant, and smile width are discussed in detail. © 2011 Wiley Periodicals, Inc.

  13. Critical component wear in heavy duty engines

    CERN Document Server

    Lakshminarayanan, P A

    2011-01-01

    The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading.  Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon r

  14. Quality control methods in accelerometer data processing: defining minimum wear time.

    Directory of Open Access Journals (Sweden)

    Carly Rich

    Full Text Available BACKGROUND: When using accelerometers to measure physical activity, researchers need to determine whether subjects have worn their device for a sufficient period to be included in analyses. We propose a minimum wear criterion using population-based accelerometer data, and explore the influence of gender and the purposeful inclusion of children with weekend data on reliability. METHODS: Accelerometer data obtained during the age seven sweep of the UK Millennium Cohort Study were analysed. Children were asked to wear an ActiGraph GT1M accelerometer for seven days. Reliability coefficients(r of mean daily counts/minute were calculated using the Spearman-Brown formula based on the intraclass correlation coefficient. An r of 1.0 indicates that all the variation is between- rather than within-children and that measurement is 100% reliable. An r of 0.8 is often regarded as acceptable reliability. Analyses were repeated on data from children who met different minimum daily wear times (one to 10 hours and wear days (one to seven days. Analyses were conducted for all children, separately for boys and girls, and separately for children with and without weekend data. RESULTS: At least one hour of wear time data was obtained from 7,704 singletons. Reliability increased as the minimum number of days and the daily wear time increased. A high reliability (r = 0.86 and sample size (n = 6,528 was achieved when children with ≥ two days lasting ≥10 hours/day were included in analyses. Reliability coefficients were similar for both genders. Purposeful sampling of children with weekend data resulted in comparable reliabilities to those calculated independent of weekend wear. CONCLUSION: Quality control procedures should be undertaken before analysing accelerometer data in large-scale studies. Using data from children with ≥ two days lasting ≥10 hours/day should provide reliable estimates of physical activity. It's unnecessary to include only children

  15. Esthetic evaluation of dental and gingival asymmetries.

    Science.gov (United States)

    Fernandes, Liliana; Pinho, Teresa

    2015-06-01

    The aim of this study was to determine which smile asymmetries were less esthetic, dental or gingival. Laypeople (297), generalists (223), prosthodontists (50) and orthodontists (49), evaluated the esthetics of digitally-modified images taken from the same frontal intra-oral photograph, using the same lips, simulating upper maxillary midline shift, occlusal plane inclination, asymmetric incisal edge and asymmetric gingival migration. The images were later paired into 3 groups. The only ones considered esthetic were the asymmetric incisal edge of the 0.5 mm shorter upper central incisor and the asymmetric gingival migration (2 mm) of the upper central incisor. In the paired images, upper maxillary midline shift vs. occlusal plane inclination, the former was rated less esthetic, while in the asymmetric incisal edge vs. asymmetric gingival migration pair, the latter was considered to be less esthetic. Laypeople and generalists consider smiles more attractive. The only images considered esthetic were the asymmetric incisal edge of the central incisor shorter by 0.5 mm and the 2 mm asymmetric gingival migration of the upper central incisor. In the horizontal plane (maxillary midline shift vs. occlusal plane cant), the dental asymmetries were considered less esthetic than the gingival asymmetries. However, in the vertical plane (asymmetric incisal edge vs. asymmetric gingival migration) the opposite was recorded. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

  16. Stress analysis and collapse time prediction of nuclear fuel cladding tube with wear scar

    International Nuclear Information System (INIS)

    Lee, J. S.; Kim, O. H.; Kim, H. K.; Hu, Y. H.; Kim, J. I.; Kim, K. T.

    2004-01-01

    In this analysis, the stress and collapse time analysis models for nuclear fuel rod with the fretting wear scar were developed in order to evaluate the effects of the wear depth on the integrity of nuclear fuel rod. The stress analysis result shows that the nuclear fuel rod with approximately 60% deep wear scar of the clad wall thickness, meets the allowable stress criteria and the collapse time analysis indicates that the fuel rod with less than roughly 56% deep wear scar of the clad wall thickness has longer collapse time than the expected fuel life-time. The both stress and collapse time results are evaluated to be very reasonable on considering the comparison with the outputs of existing design code for the simple model. However, the developed analysis models and the results will be confirmed by the tests

  17. Clinical Performance of a Combined Approach for the Esthetic ...

    African Journals Online (AJOL)

    2017-09-14

    Sep 14, 2017 ... leads to mild to severe esthetic problems requiring esthetic ... esthetic management of dental fluorosis, ranging from bleaching ... approaches such involving the use of composite or ceramic .... smoking or poor dental health.

  18. Wear properties of dental ceramics and porcelains compared with human enamel.

    Science.gov (United States)

    D'Arcangelo, Camillo; Vanini, Lorenzo; Rondoni, Giuseppe D; De Angelis, Francesco

    2016-03-01

    Contemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with human enamel and traditional gold based alloys needs to be better investigated. The purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 different dental ceramics, including a recently introduced zirconia-reinforced lithium silicate ceramic (Celtra Duo). Cylindrical specimens were fabricated from a Type III gold alloy (Aurocast8), 2 hot pressed ceramics (Imagine PressX, IPS e.max Press), 2 CAD/CAM ceramics (IPS e.max CAD, Celtra Duo), and a CAD/CAM feldspathic porcelain (Vitablocs Mark II) (n=10). Celtra Duo was tested both soon after grinding and after a subsequent glaze firing cycle. Ten flat human enamel specimens were used as the control group. All specimens were subjected to a 2-body wear test in a dual axis mastication simulator for 120000 loading cycles against yttria stabilized tetragonal zirconia polycrystal cusps. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed with 1-way ANOVA tests (α=.05). The wear depth (0.223 mm) of gold alloy was the closest to that of human enamel (0.217 mm), with no significant difference (P>.05). The greatest wear was recorded on the milled Celtra Duo (wear depth=0.320 mm), which appeared significantly less wear resistant than gold alloy or human enamel (Pceramics did not statistically differ in comparison with the human enamel. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  19. Association of overjet and overbite with esthetic impairments of oral health-related quality of life.

    Science.gov (United States)

    Sierwald, Ira; John, Mike T; Schierz, Oliver; Jost-Brinkmann, Paul-Georg; Reissmann, Daniel R

    2015-09-01

    Esthetics is an important part of quality of life and a frequent reason for orthodontic treatment demand. It was the aim of this study to investigate whether esthetic impairments, related to overjet and overbite, can be assessed with an established oral health-related quality of life instrument. Data from 1968 participants (age: 16-90 years; 69.8% female) from three German surveys were analyzed. Esthetic impairments of oral health-related quality of life were measured with four questions of the Oral Health Impact profile (OHIP), which comprise esthetic aspects of oral health-related quality of life. Higher values represent greater esthetic impairment (sum score: 0-16). Overbite and overjet values were categorized (≤ - 1 mm, 0-1 mm, 2-3 mm, 4-5 mm, ≥ 6 mm). The specific impact of each category on esthetic impairment, in relation to the reference category (2-3 mm), was calculated in linear regression analyses. The type of relationship and the specific impact of overbite and overjet were evaluated in regression analyses with fractional polynomials. Overbite ranged from - 5 to 15 mm (mean: 3.2 mm) and overjet from - 7 to 19 mm (mean: 3.1 mm). Both an increase and a decrease in overjet, in relation to the reference category, resulted in more esthetic-related oral health-related quality of life impairments. However, in this model, only the effect for increased overjet was statistically significant (4-5 mm: + 0.4 OHIP points; ≥ 6 mm: + 0.9 OHIP points). In the regression analysis with fractional polynomials, both an increase and a decrease in overjet resulted in more esthetic impairments, characterized by a U-shaped relationship. No association could be verified for overbite. A substantial increase or decrease of overjet from the reference values is associated with esthetic impairments of oral health-related quality of life, whereas the extent of overbite seems to have no impact on esthetics.

  20. Optical wear monitoring

    Science.gov (United States)

    Kidane, Getnet S; Desilva, Upul P.; He, Chengli; Ulerich, Nancy H.

    2016-07-26

    A gas turbine includes first and second parts having outer surfaces located adjacent to each other to create an interface where wear occurs. A wear probe is provided for monitoring wear of the outer surface of the first part, and includes an optical guide having first and second ends, wherein the first end is configured to be located flush with the outer surface of the first part. A fiber bundle includes first and second ends, the first end being located proximate to the second end of the optical guide. The fiber bundle includes a transmit fiber bundle comprising a first plurality of optical fibers coupled to a light source, and a receive fiber bundle coupled to a light detector and configured to detect reflected light. A processor is configured to determine a length of the optical guide based on the detected reflected light.

  1. Esthetic dental anomalies as motive for bullying in schoolchildren.

    Science.gov (United States)

    Scheffel, Débora Lopes Salles; Jeremias, Fabiano; Fragelli, Camila Maria Bullio; Dos Santos-Pinto, Lourdes Aparecida Martins; Hebling, Josimeri; de Oliveira, Osmir Batista

    2014-01-01

    Facial esthetics, including oral esthetics, can severely affect children's quality-of-life, causing physical, social and psychological impairment. Children and adolescents with esthetic-related dental malformations are potential targets for bullies. This study was aimed to present and discuss patients who suffered from bullying at school and family environment due to esthetic-related teeth anomalies. Providing an adequate esthetic dental treatment is an important step in their rehabilitation when the lack of esthetic is the main source of bullying. After dental treatment, we noted significant improvement in self-esteem, self-confidence, socialization and academic performance of all patients and improvement in parental satisfaction regarding the appearance of their children. It is imperative that both family and school care providers be constantly alert about bullying in order to prevent or interrupt aggressive and discriminatory practices against children and adolescents. Clearly, dental anomalies may be a motive for bullying.

  2. The analysis of mechanism of rhenium-coated tools' wear-resistance rising

    Directory of Open Access Journals (Sweden)

    Daniel Petrosyan

    2017-06-01

    Full Text Available It is proposed to obtain wear-resistant layers on the hard-alloy materials by thermochemical treatment. In the different field of production – mechanical engineering, metallurgy and military technologies, with machine parts demanding high wearproof and corrosion-proof machinery parts on the surfaces of syntheses of diamonds, with metal surface thermal-diffusion with rhenium, to receive diffusion wearing layers for the first time. A method for thermochemical treatment of hard alloy plates has been investigated, allowing to raise the wear-resistance of cutting and mining tools.

  3. Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

    Directory of Open Access Journals (Sweden)

    P. Ilanthirayan

    2017-12-01

    Full Text Available The piston rings are the most important part in engine which controls the lubricating oil consumption and blowby of the gases. The lubricating film of oil is provided to seal of gases towards crankcase and also to give smooth friction free translatory motion between rings and liner. Of the three rings present top ring is more crucial as it does the main work of restricting gases downwards the crankcase. Boundary lubrication is present at the Top dead centre (TDC and Bottom dead centre (BDC of the liner surface. In addition to this, top ring is exposed to high temperature gases which makes the oil present near the top ring to get evaporated and decreasing its viscosity, making metal-metal contact most of the time. Due to this at TDC, excess wear happens on the liner which is termed as Top ring reversal bore wear. The wear rate depends upon many parameters such as lubrication condition, viscosity index, contact type, normal forces acting on ring, geometry of ring face, surface roughness, material property. The present work explores the wear depth for different geometries of barrel ring using Finite Element model with the help of Archard wear law and the same is validated through experimentation. The study reveals that Asymmetric barrel rings have less contact pressure which in turn reduces the wear at Top dead centre.

  4. Cosmetics and the esthetic patient and laboratory communication.

    Science.gov (United States)

    Feeley, R T

    1995-08-01

    With increasing consumer awareness of the innovative procedures available for cosmetic dentistry, this area of practice is growing rapidly and has become an excellent source for patient referrals. Unfortunately, it can also be a large source of stress for the practitioner. Esthetics has been described by The Pocket Oxford Dictionary as "the philosophy of beautiful"; its perception varies from individual to individual. In the field of dentistry, there are criteria which define one tooth as being more esthetic than another and one individual's smile as more pleasing than another. However, that which is esthetically pleasing to the clinician may not be esthetically pleasing to the patient.

  5. [Social and esthetic care in oncology, a part of the patient's journey].

    Science.gov (United States)

    Christ, Dominique; Reaux, Martine

    2013-10-01

    Socio-aesthetic care in oncology, a parenthesis in the patient's journey. Socio-aesthetics, which is an aspect of support care, is carried out within the hospital. The treatments given into the suggestion of paramedical teams or at the request of patients provide relief and well-being to women and men who are treated for cancer. Recourse to services of socio-esthetics at various stages of the cancer treatment helps avoid isolation, regain confidence in one's self image and prepare for life "after cancer".

  6. IMPROVEMENT OF WEAR-RESISTANCE AND SERVICE LIFE OF MULTI-DISK BRAKE MECHANISMS OF «BELARUS» TRACTOR BY LASER THERMAL HARDENING OF FAST WEARING PARTS

    Directory of Open Access Journals (Sweden)

    O. S. Kobjakov

    2008-01-01

    Full Text Available Problems concerning wear resistance improvement of «Belarus» tractor brake mechanism parts are considered in the paper. Properties of ВЧ-50-pig iron are investigated as a result of laser thermal hardening by various technological methods.

  7. Microstructure and Wear Properties of Electron Beam Melted Ti-6Al-4V Parts: A Comparison Study against As-Cast Form

    Directory of Open Access Journals (Sweden)

    Wei Quan Toh

    2016-11-01

    Full Text Available Ti-6Al-4V (Ti64 parts of varying thicknesses were additively manufactured (AM by the powder-bed-based electron beam melting (EBM technique. Microstructure and wear properties of these EBM-built Ti-6Al-4V parts have been investigated in comparison with conventionally cast Ti64 samples. Sliding wear tests were conducted using a ball-on-disc micro-tribometer under ambient conditions. Experimental results reveal that EBM-built Ti64 samples exhibited higher microhardness and an overall larger coefficient of friction as compared to the as-cast counterpart. Of interest is that the corresponding specific wear volumes were lower for EBM-built Ti64 samples, while the as-cast Ti64 showed the poorest wear resistance despite its lower coefficient of friction. Wear mechanisms were provided in terms of quantitative microstructural characterization and detailed analysis on coefficient of friction (COF curves.

  8. Comparative analysis of rationale used by dentists and patient for final esthetic outcome of dental treatment.

    Science.gov (United States)

    Reddy, S Varalakshmi; Madineni, Praveen Kumar; Sudheer, A; Gujjarlapudi, Manmohan Choudary; Sreedevi, B; Reddy, Patelu Sunil Kumar

    2013-05-01

    To compare and evaluate the perceptions of esthetics among dentists and patients regarding the final esthetic outcome of a dental treatment. Esthetics is a matter of perception and is associated with the way different people look at an object. What constitutes esthetic for a particular person may not be acceptable for another. Hence it is subjective in nature. This becomes more obvious during the post-treatment evaluation of esthetics by dentist and the concerned patient. Opinion seldom matches. Hence, the study is a necessary part of the process of understanding the mind of dentist and patient regarding what constitutes esthetics. A survey has been conducted by means of a questionnaire consisting of 10 questions, on two groups of people. First group consists of 100 dentists picked at random in Kanyakumari district of Tamil Nadu, India. Second group consisted of 100 patients who required complete denture prosthesis. The second group was divided into two subgroups A and B. Subgroup A consisting of 50 men and subgroup B consisting of 50 women. In each subgroup 25 patients were selected in age group of 40 to 50 and 25 patients were selected in the age group of 50 to 60. The questionnaire was given to both the groups and asked to fill up, which was then statistically analyzed to look for patterns of thought process among them. Results were subjected to statistical analysis by Student's t-test. Perceptions of esthetics differs from dentist who is educated regarding esthetic principles of treatment and a patient who is not subjected to such education. Since, the questions were formulated such that patients could better understand the underlying problem, the final outcome of survey is a proof that dentists need to take into account what the patient regards as esthetics in order to provide a satisfactory treatment. CLINICAL AND ACADEMIC SIGNIFICANCE: The current study helps the dentist to better educate the patient regarding esthetics so that patient appreciates the final

  9. Malocclusion: esthetic impact and quality of life among Brazilian schoolchildren.

    Science.gov (United States)

    Marques, Leandro Silva; Ramos-Jorge, Maria Letícia; Paiva, Saul Martins; Pordeus, Isabela Almeida

    2006-03-01

    The objectives of this study were to assess the esthetic impact of malocclusion on the daily life of Brazilian schoolchildren and to test the association between esthetic impact due to malocclusion and biopsychosocial variables. The sample comprised 333 randomly selected subjects aged 10 to 14 years. The oral impact on daily performance (OIDP) instrument was used to assess the esthetic impact, and the dental aesthetic index (DAI) was used for clinical assessment. The subjects were further evaluated as to their self-esteem (global self-evaluation) and self-perception of oral esthetics (oral aesthetic subjective impact scale). Other variables were assessed through questionnaires. Multiple logistic regression was used in the data analysis. Twenty-seven percent of the children reported an esthetic impact on their daily lives due to malocclusion. The following variables were independent risk factors for an esthetic impact: female sex, maxillary anterior crowding of 2 mm or more, normative need for treatment considered elective and highly desirable, negative self-perception of oral esthetics, low self-esteem, and intermediate economic level. The esthetic impact of malocclusion significantly affects the quality of life of schoolchildren in Belo Horizonte.

  10. Immediate Restoration of Immediate Implants in the Esthetic Zone of the Maxilla Via the Copy-Abutment Technique: 5-Year Follow-Up of Pink Esthetic Scores.

    Science.gov (United States)

    Fürhauser, Rudolf; Mailath-Pokorny, Georg; Haas, Robert; Busenlechner, Dieter; Watzek, Georg; Pommer, Bernhard

    2017-02-01

    Implant esthetics may benefit from individualized zirconia abutments copying the emergence profile of the natural tooth and delivered within days after immediate implant insertion. To investigate the esthetic outcome of the Copy-Abutment technique using the Pink Esthetic Score (PES). A total of 77 patients with single-tooth implants in the anterior maxilla restored at the day of immediate implant placement using Copy-Abutments and provisional crowns were followed-up after 1 week, 1 month, 4 months, 6 months, 1, 2, 3, 4, and 5 years to assess implant esthetics. PES ranged between 7 and 14 (median: 13) and improved significantly between the 6 month and 1 year follow-up (p esthetic zone show satisfactory long-term esthetic outcomes. © 2016 Wiley Periodicals, Inc.

  11. A method for simultaneous determination of wear-resistance of structurally identical machine parts with mutual friction

    International Nuclear Information System (INIS)

    Valigura, V.; Volyn'ski, A.

    1979-01-01

    There are mechanisms in the technique, boundary state of separate parts of which is determined by the process of wear of three elements of the mechanism, made of the same material (for example antifriction bearings). The main concept of wear determination in the case of such a mechanism is to conduct measurements by means of simultaneous application of three different methods, for example: the method of roentgen-fluorescence; the tracer technique with application of activation by means of irradiation by different elementary particles, practically by means of neutrons and protons; the method of artifical bases application. In the paper the method is presented having been developed in the Institute of Working Machines of the Poznan Polytechnic. This method of simultaneous investigation in the wear process of bearing rings, inner and outer, and rolling elements of roller bearings. All these elements of bearings are made of LX-15 steel. The method developed, permits to determine the wear sufficient for practical purposes sensitivity [ru

  12. Perception of Esthetic Impact of Smile Line in Complete Denture Wearers by Different Age Groups.

    Science.gov (United States)

    Pithon, Matheus Melo; Alves, Leandro Pereira; da Costa Prado, Matheus; Oliveira, Rener Leal; Costa, Matheus Souza Campos; da Silva Coqueiro, Raildo; Gusmão, João Milton Rocha; Santos, Rogério Lacerda

    2016-10-01

    To evaluate esthetic perceptions based on tooth exposure when smiling of patients wearing complete dentures by evaluators in different age groups. Alterations were made to a front view photograph of a smiling patient wearing complete maxillary and mandibular dentures. Alterations in the smile line were simulated to increase or decrease tooth exposure (increments of 0.5 mm). For this purpose, image manipulation software was used. After manipulation, images were printed on photo paper, attached to a questionnaire, and distributed to individuals in three age groups (n = 150). To evaluate the esthetic perception for each image, a visual analog scale was used, with 0 representing least attractive, 5 representing attractive, and 10 representing very attractive. Differences between examiners were analyzed using the Mann-Whitney test. All statistical analyses were performed with a degree of confidence of 95%. Two evaluators did not observe any differences between images. The images given the best and worst scores were E and O (alterations of 2 and 7 mm), respectively, in the 15- to 19-year-old group, B and O (alterations of 0.5 and 7 mm), respectively, in the 35- to 44-year-old group, and A and M (no alteration and 6 mm alteration), respectively, in the 65- to 74-year-old group. When the images were presented together (images 1 and 2), the unaltered image was selected by individuals of different age groups as the best, and the image with a change of 7 mm was selected as the worst. In this study, complete dental prostheses with smile lines that coincided with the cervical margins of the anterior teeth were the most acceptable. Less exposure of the maxillary teeth when smiling corresponded with decreased attractiveness. © 2015 by the American College of Prosthodontists.

  13. Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

    Science.gov (United States)

    Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

    2016-01-01

    Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

  14. Researches concerning the ultasonic energy influence on the resistence to the abrasive wear of loaded welded parts

    Directory of Open Access Journals (Sweden)

    Gh. Amza

    2013-01-01

    Full Text Available The researches presented in the paper refer to the effect of ultrasounds propagation in the liquid metal bath on the process of transferring the additive material through the electric arch and on the crystallization process, and all these effects are analyzed for loaded welded parts solicited at the abrasive wear. All these influences are conferred to these two basic phenomena due to the ultrasounds propagation in liquid environments, namely, ultra-acoustic cavitation and acceleration of the diffusion process. The results concerns the resistance to the wear obtained for the loaded parts through manual welding with electric arch and classically covered electrode and ultrasonically activated.

  15. Guidance flap choice for lip cancer: Principles, timing and esthetic-functional results

    Directory of Open Access Journals (Sweden)

    Attilio Carlo Salgarelli

    2016-01-01

    Conclusion: We share the widespread view that a surgeon who performs a reconstruction using the minimal tissue components required to close the lesion will achieve the best results. Reconstruction does not influence prognosis and overall should be oriented to the defect. Careful, clean, and safe resection of lip carcinoma, with creation of healthy margins, can be followed by functional and esthetic lip reconstruction.

  16. Cutting tool wear monitoring with the use of impedance layers

    OpenAIRE

    Sadílek, Marek; Kratochvíl, Jiří; Petrů, Jana; Čep, Robert; Zlámal, Tomáš; Stančeková, Dana

    2014-01-01

    The article deals with problems of cutting process monitoring in real time. It is focused on tool wear by means of impedance layers applied on ceramic cutting inserts. In the experimental part the cutting process is monitored using electrical resistance measurement. The results are compared and verified using the monitored cutting temperature and tool wear. The testing of impedance layers is reasonable mainly for cutting edge diagnostics. The width of this layer determines the wear allowance ...

  17. Towards Uniform Accelerometry Analysis: A Standardization Methodology to Minimize Measurement Bias Due to Systematic Accelerometer Wear-Time Variation

    Directory of Open Access Journals (Sweden)

    Tarun R. Katapally, Nazeem Muhajarine

    2014-06-01

    Full Text Available Accelerometers are predominantly used to objectively measure the entire range of activity intensities – sedentary behaviour (SED, light physical activity (LPA and moderate to vigorous physical activity (MVPA. However, studies consistently report results without accounting for systematic accelerometer wear-time variation (within and between participants, jeopardizing the validity of these results. This study describes the development of a standardization methodology to understand and minimize measurement bias due to wear-time variation. Accelerometry is generally conducted over seven consecutive days, with participants' data being commonly considered 'valid' only if wear-time is at least 10 hours/day. However, even within ‘valid’ data, there could be systematic wear-time variation. To explore this variation, accelerometer data of Smart Cities, Healthy Kids study (www.smartcitieshealthykids.com were analyzed descriptively and with repeated measures multivariate analysis of variance (MANOVA. Subsequently, a standardization method was developed, where case-specific observed wear-time is controlled to an analyst specified time period. Next, case-specific accelerometer data are interpolated to this controlled wear-time to produce standardized variables. To understand discrepancies owing to wear-time variation, all analyses were conducted pre- and post-standardization. Descriptive analyses revealed systematic wear-time variation, both between and within participants. Pre- and post-standardized descriptive analyses of SED, LPA and MVPA revealed a persistent and often significant trend of wear-time’s influence on activity. SED was consistently higher on weekdays before standardization; however, this trend was reversed post-standardization. Even though MVPA was significantly higher on weekdays both pre- and post-standardization, the magnitude of this difference decreased post-standardization. Multivariable analyses with standardized SED, LPA and

  18. Amelogenesis imperfecta: A challenge to restoring esthetics and function

    Directory of Open Access Journals (Sweden)

    Ranganath V

    2010-01-01

    Full Text Available Rehabilitation of complicated cases poses difficulty in clinical practice, both with respect to restoring function and with esthetics. One such clinical condition where the dentist has to give importance to proper planning of the treatment and execution of the plan is amelogenesis imperfecta (AI, a condition where both function and esthetics are accommodated. This article discusses both the functional and esthetic rehabilitation of a patient with AI. Both the esthetics and function were hampered in this patient due to the condition. As a result, the treatment was properly planned and executed. A number of treatment options are available for us today to treat such a case. There is no one technique to be followed as such. However, the aim was to properly diagnose the case and provide good function and esthetics to the patient.

  19. Bridge esthetic guidelines.

    Science.gov (United States)

    1975-01-01

    As esthetics is not an exact science, differences of opinion occur, even between experts; however, studies had found that in most cases there were statistical preferences. These preferences are presented. For the convenience of the designer, a format...

  20. Photos vs silhouettes for evaluation of African American profile esthetics.

    Science.gov (United States)

    Hockley, Andrew; Weinstein, Martin; Borislow, Alan J; Braitman, Leonard E

    2012-02-01

    Patient photos and silhouettes are commonly used in clinical evaluations and orthodontic research to evaluate profile esthetics. The purpose of this study was to determine whether the use of photos or silhouettes is a more appropriate method of evaluating African American profile esthetics and whether there are different profile esthetic preferences among clinicians when using photos compared with silhouettes. Pretreatment records of 20 adolescent African American patients were selected (10 male, 10 female) from the orthodontic clinic at the Albert Einstein Medical Center in Philadelphia. Each patient's profile photo was digitally changed with imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif) to fabricate a series of 7 photos and 7 silhouettes with lip positions at uniform distances relative to Ricketts' E-line standard. Fifteen raters consisting of orthodontic faculty and residents were asked to select the most esthetically pleasing profile from each patient's photo series and silhouette series. More rater preferences for the photographs (86%) were within the acceptable esthetic range (within 2 mm of the E-line in either direction) than were their preferences for silhouettes (66%) (P esthetic norm were more often preferred in the silhouettes than in the photos. Thirty-one percent of the silhouettes preferred by the raters were flatter than the norm compared with 9% of the photos (P = 0.003). Fuller profiles were preferred in only 3% of the silhouettes and 5% of the photos (P = 0.6). Esthetic attractiveness of faces of African American orthodontic patients is rated differently in photos and silhouettes. When evaluating soft-tissue esthetic profile preferences, rater preferences in the photographs were closer to the established esthetic norm than were their preferences in the silhouettes. Using silhouettes to evaluate patient esthetics could influence clinicians or researchers to select profiles that are flatter than the established

  1. Study of wear performance of deep drawing tooling

    Science.gov (United States)

    Naranje, Vishal G.; Karthikeyan, Ram; Nair, Vipin

    2017-09-01

    One of the most common challenges for many of the mechanical engineers and also in the field of materials science is the issue of occurrences of wear of the material parts which is used in certain applications that involves such surface interactions. In this paper, wear behaviour of particular grade High Carbon High Chromium Steel and many most famously D2, H13, O1 known as the Viking steel has been studied, evaluated and analyzed under certain processing parameters such as speed, load, track diameter and time required for deep drawing process to know it’s the wear rate and coefficient of friction. Also, the significance of the processing parameters which is used for wear testing analysis is also examined.

  2. Comparative evaluation of esthetic changes in nonpitted fluorosis stains when treated with resin infiltration, in-office bleaching, and combination therapies.

    Science.gov (United States)

    Gugnani, Neeraj; Pandit, I K; Gupta, Monika; Gugnani, Shalini; Soni, Sugandhi; Goyal, Virender

    2017-09-01

    Dental fluorosis leads to esthetic deviation and varies from nonpitted white opacities, dark brown stains to pitting or structural breakdown of enamel surface. Treatment for fluorosis depends on the severity of condition and includes both noninvasive methods and invasive methods. Recently resin infiltration has been proposed as an alternative treatment for nonpitted fluorosis. This study was done to evaluate the esthetic changes in nonpitted fluorosis stains when treated with resin infiltration, in-office bleaching and combination therapies. The present study is a randomized, single blinded controlled trial with four parallel arms with 1:1 allocation ratio. The intervention arms included bleaching with 35% hydrogen peroxide, resin infiltration, resin infiltration with increased infiltration time and a combination approach of bleaching and infiltration. Immediate esthetic changes were evaluated for two parameters including, 'Change in esthetics' and 'Improvement in opacities/stains' using a VAS scale by two independent observers. Kruskal-Wallis test and Mann-Whitney U-test were done for intergroup comparisons. Best results for both the parameters were observed among patients treated with resin infiltration with increased infiltration time. Mann-Whitney U test revealed significantly better results for resin infiltration groups (alone or combination with bleaching) as compared to bleaching alone (P esthetics and improvement in stains. White and brown opacities due to fluorosis have always been a concern for esthetics. In our study, resin infiltration technique with tailored etching times and increased infiltration time exhibited best immediate esthetic improvement for nonpitted fluorotic opacities and stains. These esthetic outcomes reaffirm the applicability of RI technique for nonpitted fluorosis, which was originally advocated only for white spot lesions due to early caries. This will in turn help the dentists to plan the esthetic management of nonpitted fluorosis

  3. Wear-Out Sensitivity Analysis Project Abstract

    Science.gov (United States)

    Harris, Adam

    2015-01-01

    During the course of the Summer 2015 internship session, I worked in the Reliability and Maintainability group of the ISS Safety and Mission Assurance department. My project was a statistical analysis of how sensitive ORU's (Orbital Replacement Units) are to a reliability parameter called the wear-out characteristic. The intended goal of this was to determine a worst case scenario of how many spares would be needed if multiple systems started exhibiting wear-out characteristics simultaneously. The goal was also to determine which parts would be most likely to do so. In order to do this, my duties were to take historical data of operational times and failure times of these ORU's and use them to build predictive models of failure using probability distribution functions, mainly the Weibull distribution. Then, I ran Monte Carlo Simulations to see how an entire population of these components would perform. From here, my final duty was to vary the wear-out characteristic from the intrinsic value, to extremely high wear-out values and determine how much the probability of sufficiency of the population would shift. This was done for around 30 different ORU populations on board the ISS.

  4. Esthetics built to last: treatment of functional anomalies may need to precede esthetic corrections.

    Science.gov (United States)

    Bassett, Joyce L

    2014-02-01

    In this case of a 33 year-old male patient seeking a more esthetically pleasing smile, comprehensive restorative treatment planning included recognition of the patient's incisor position and morphology, dentofacial requirements, and appropriate vertical dimension. The accepted treatment plan consisted of orthodontic correction of the patient's anterior constriction, followed by placement of eight maxillary veneers and composite augmentation on the mandibular incisors and canines. Keys to achieving a successful outcome included knowledge of smile design, material selection, and preparation techniques. The case demonstrates how functional problems oftentimes must be addressed before esthetic correction can be made.

  5. The human dimension: esthetics in society and in medicine.

    Science.gov (United States)

    Talarico, Giorgio; Morgante, Ezio

    2013-01-01

    This research has been carried out to transmit a multidisciplinary knowledge of esthetics in society and in the field of science (psychology, sociology, philosophy, medicine, art, ethics). This knowledge is necessary to ensure that esthetic doctors who deal with esthetic medicine may, through their intervention - which is not only analytical, but also creative - respecting human nature, people's esthetic expectations and the rules of social ethics. This is the only way we can best respond to the overall concept referred to as the human dimension. This may be carried out in different ways and contexts that are current and are an expression of the age we are living in.

  6. Esthetics of Flapless Single-Tooth Implants in the Anterior Maxilla Using Guided Surgery: Association of Three-Dimensional Accuracy and Pink Esthetic Score.

    Science.gov (United States)

    Fürhauser, Rudolf; Mailath-Pokorny, Georg; Haas, Robert; Busenlechner, Dieter; Watzek, Georg; Pommer, Bernhard

    2015-10-01

    Flapless implant placement using surgical templates may guarantee predictable and esthetic results provided that preplanned implant positions are transfered precisely into surgical reality. The study aims to investigate the effect of three-dimensional accuracy in guided implant surgery on the esthetic outcome of single-tooth implants in the anterior maxilla. Single-tooth implants for delayed replacement of upper incisors were inserted in 27 patients using stereolithographic templates. Superimposition of postoperative cone beam computed tomography (CBCT) scans allowed assessment of positional inaccuracy at the implant shoulder and apex, as well as angular deviation. Objective evaluation of implant esthetics was performed after a mean follow-up of 2.3 years using the Pink Esthetic Score (PES). Mean deviation between planned and actual implant position was 0.84 mm at the implant shoulder and significantly correlated to average PES of 12 (p = .031). Inaccuracy toward the buccal side was most frequent (70%). Deviations  ≥  0.8  mm resulted in significantly worse implant esthetics (median PES: 9.5, interquartile range [IQR]: 8-11) compared with more accurate implant positions (median PES: 13, IQR: 12-13, p = .039). Positional inaccuracy is low in guided implant surgery, but may however significantly compromise implant esthetics in the anterior maxilla. © 2014 Wiley Periodicals, Inc.

  7. Effects of build parameters on linear wear loss in plastic part produced by fused deposition modeling

    Science.gov (United States)

    Mohamed, Omar Ahmed; Masood, Syed Hasan; Bhowmik, Jahar Lal

    2017-07-01

    Fused Deposition Modeling (FDM) is one of the prominent additive manufacturing technologies for producing polymer products. FDM is a complex additive manufacturing process that can be influenced by many process conditions. The industrial demands required from the FDM process are increasing with higher level product functionality and properties. The functionality and performance of FDM manufactured parts are greatly influenced by the combination of many various FDM process parameters. Designers and researchers always pay attention to study the effects of FDM process parameters on different product functionalities and properties such as mechanical strength, surface quality, dimensional accuracy, build time and material consumption. However, very limited studies have been carried out to investigate and optimize the effect of FDM build parameters on wear performance. This study focuses on the effect of different build parameters on micro-structural and wear performance of FDM specimens using definitive screening design based quadratic model. This would reduce the cost and effort of additive manufacturing engineer to have a systematic approachto make decision among the manufacturing parameters to achieve the desired product quality.

  8. BASES OF SCHOOL CHILDREN'S ESTHETIC JUDGMENT AND ESTHETIC PREFERENCE.

    Science.gov (United States)

    CHILD, IRVIN L.; AND OTHERS

    RESEARCH INTO CHILDREN'S ART PREFERENCES AND THEIR RELATION TO THE ESTHETIC MERIT OF ART AS JUDGED BY EXPERTS WAS DESCRIBED IN THIS REPORT THAT IS MADE UP OF NINE ARTICLES, ORIGINALLY PREPARED FOR PUBLICATION IN SCHOLARLY JOURNALS, AND A SUMMARY OF THE FINDINGS. THE GENERAL TOPICS CONSIDERED WERE (1) REASONS CHILDREN GIVE FOR THEIR PREFERENCES,…

  9. Zirconia crowns for rehabilitation of decayed primary incisors: an esthetic alternative.

    Science.gov (United States)

    Ashima, G; Sarabjot, K Bhatia; Gauba, K; Mittal, H C

    2014-01-01

    Esthetic management of extensively decayed primary maxillary anterior teeth requiring full coronal coverage restoration is usually challenging to the pediatric dentists especially in very young children. Many esthetic options have been tried over the years each having its own advantages, disadvantages and associated technical, functional or esthetic limitations. Zirconia crowns have provided a treatment alternative to address the esthetic concerns and ease of placement of extra-coronal restorations on primary anterior teeth. The present article presents a case where grossly decayed maxillary primary incisors were restored esthetically and functionally with ready made zirconia crowns (ZIRKIZ, HASS Corp; Korea). After endodontic treatment the decayed teeth were restored with zirconia crowns. Over a 30 months period, the crowns have demonstrated good retention and esthetic results. Dealing with esthetic needs in children with extensive loss of tooth structure, using Zirconia crowns would be practical and successful. The treatment described is simple and effective and represents a promising alternative for rehabilitation of decayed primary teeth.

  10. Rod cluster control assemblies and rod cluster control guide tubes: wear and drop time

    International Nuclear Information System (INIS)

    Zbinden, M.

    1997-01-01

    The wear of RCCAs and of RCC guide tubes is due to two quite different mechanisms and the remedies to apply for each case might lead to contradictory solutions: - the impact/sliding wear for the seldom moving RCCAs, namely the shutdown RCCAs, under flow-induced vibrations, - the axial sliding wear for the control rods subjected to the stepping movements ordered by the acting load. In this case the hydraulic sticking forces are those which produce an evolution of the surface states that may increase the drop time. The introduction, an historical survey of the encountered difficulties, is followed by short description of the components and then the paper presents contributions of EDF in the R and D field, which take place in two successive multi-annual projects. Lastly, some information is given about the recent evolutions and new problems as well for impact/sliding wear as for drop time under normal or seismic conditions. (author)

  11. [Gingival health and esthetics--another aspect of objectives of orthodontic treatment].

    Science.gov (United States)

    Ai, Dongqing; Xu, Hui; Bai, Ding

    2013-04-01

    Contemporary orthodontic care should be a team approach to achieve health and esthetics of soft and hard tissue. It should be given enough attention that periodontal health provides the foundation for tooth movement, and that distinct esthetic results can be achieved by subtle changes in tooth alignment and gingival contours. Orthodontic treatment planning should include evaluation of gingival health and esthetics to anticipate the need for interdisciplinary approaches. Studies on the effect of orthodontic treatment on gingiva can provides basis for maintaining gingival health and esthetic. This article will focus primarily on the gingival health and esthetic care in orthodontic treatment.

  12. Two-body wear rate of CAD/CAM resin blocks and their enamel antagonists.

    Science.gov (United States)

    Stawarczyk, Bogna; Özcan, Mutlu; Trottmann, Albert; Schmutz, Felix; Roos, Malgorzata; Hämmerle, Christoph

    2013-05-01

    Computer-aided design and computer-aided manufacturing (CAD/CAM) resins exhibit good mechanical properties and can be used as long-term restorations. The wear rate of such resins and their enamel antagonists is unknown. The purpose of this study was to test and compare the 2-body wear rate of CAD/CAM resin blocks. Wear specimens (N=42, n=6) were made from 5 CAD/CAM resins: ZENO PMMA (ZP), artBloc Temp (AT), Telio CAD (TC), Blanc High-class (HC), CAD-Temp (CT); 1 manually polymerized resin: Integral esthetic press (negative control group, IEP); and 1 glass-ceramic: VITA Mark II (positive control group, VM2). The specimens for the wear resistance were aged in a thermomechanical loading machine (49 N, 1.67 Hz, 5/50°C) with human enamel antagonists. The material loss of all specimens before, during, and after aging was evaluated with a 3DS profilometer. The measured material loss data of all tested groups were statistically evaluated with linear mixed model analysis (a=.05). Manually polymerized resin showed significantly higher material wear (P<.001) than all other tested groups. Glass-ceramic showed significantly lower wear values (P<.001) than CAD/CAM resins ZP, AT, HC, CT, and IES. CAD/CAM resin TC was not significantly different from the positive control group. Glass-ceramic showed the highest enamel wear values (P<.001) of all tested resins. No differences were found in the enamel wear among all resins. The glass-ceramic group showed damage in the form of cracks on the worn enamel surface in 50% of specimens. CAD/CAM resins showed lower wear rates than those conventionally polymerized. Only one CAD/CAM resin, TC, presented material wear values comparable with glass-ceramic. The tested glass-ceramic developed cracks in the enamel antagonist and showed the highest enamel wear values of all other tested groups. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  13. THE WEAR OF INJECTION MOULD FUNCTIONAL PARTS IN CONTACT WITH POLYMER COMPOSITES

    Directory of Open Access Journals (Sweden)

    Janette Brezinová

    2009-02-01

    Full Text Available The paper deals with the evaluation of material wear of injection moulds made of aluminium alloy Alumec 89 and copper alloy Moldmax HH in friction couples with plastomer materials with various filler contents. The friction relations in injection moulding were simulated in an adhesion dry wear test using an Amsler machine, with an area contact of the friction couple materials. The wear intensity was evaluated by determination of friction coefficient and relative wearing by the mass loss. Surface morphology changes of evaluated alloys after wear and the thermal conditions in particular friction couples were analysed simultaneously.

  14. Virtual sensors for on-line wheel wear and part roughness measurement in the grinding process.

    Science.gov (United States)

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A; Cabanes, Itziar; Pombo, Iñigo

    2014-05-19

    Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs) for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor's results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm). In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm). The present approach can be easily generalized to other grinding operations.

  15. Esthetic evaluation of single-tooth implants in the anterior mandible.

    Science.gov (United States)

    Hof, Markus; Tepper, Gabor; Koller, Barbara; Krainhöfner, Martin; Watzek, Georg; Pommer, Bernhard

    2014-09-01

    Single-tooth replacement of anterior mandibular teeth is frequently complicated by insufficient bucco-lingual bone width and limited mesio-distal space available for implant placement. The aim of the present study was to assess implant esthetics in the partially edentulous anterior mandible. Esthetic evaluation of 43 anterior mandibular single-tooth implants in 15 women and 28 men was performed using esthetic indices (PES = Pink Esthetic Score, PI = Papilla Index, SES = Subjective Esthetic Score) as well as subjective patients' Visual Analogue Scale (VAS) ratings. Clinical and radiological parameters (implant and crown dimensions, pocket depth, bleeding on probing, plaque, keratinized mucosa, marginal bone level, and distance to adjacent teeth) were tested for influence. Implant esthetics were judged satisfactory (PES ≤10) in 42% of implants compared with a patient satisfaction rate of 87%. Correlation between objective indices (PES/PI: rs  = 0.62, PES/SES: rs  = -0.73, PI/SES: rs  = -0.48) was highly significant (P ≤ 0.001); however, no association to subjective patients' ratings could be observed. Type of prosthetic restoration (single crown vs. tulip-shaped double crowns), mesio-distal crown width as well as anatomic crown length significantly affected esthetic scores. Patients' judgment, by contrast, could not be associated to any prognostic factor. Subjective patient satisfaction with implant esthetics in the partially edentulous anterior mandible is high, however, remains hard to predict or objectively quantify. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Esthetic Rehabilitation with a Cast Partial Denture

    Directory of Open Access Journals (Sweden)

    Suraksha Shrestha

    2017-01-01

    Full Text Available Removable partial denture is a treatment option where fixed prosthesis is not indicated. Due to its esthetic problems in the anterior region various modifications have been designed for its fabrication. This article describes an esthetic alternative using a round rest distal depression clasp for maxillary anterior teeth abutment while restoring the missing teeth with a cast partial denture.

  17. Use of the ditramax system to communicate esthetic specifications to the laboratory.

    Science.gov (United States)

    Margossian, Patrice; Laborde, Gilles; Koubi, Stephen; Couderc, Gullaume; Mariani, Paul

    2011-01-01

    Prosthetic restoration of the anterior teeth is a major esthetic challenge. Esthetic treatment consists of creating pleasantly proportioned teeth and integrating them harmoniously into the patient's gingiva, lips, and face. The communication of clinical data to the laboratory is critical to the success of any esthetic treatment. The purpose here is to present a straightforward, efficient, and reproducible means of communicating esthetic specifications to ceramists, allowing them to work as though the patient was actually in front of them, with access to all of the major facial esthetic criteria.

  18. Do you like Arcimboldo's? Esthetic appreciation modulates brain activity in solving perceptual ambiguity.

    Science.gov (United States)

    Boccia, M; Nemmi, F; Tizzani, E; Guariglia, C; Ferlazzo, F; Galati, G; Giannini, A M

    2015-02-01

    Esthetic experience is a unique, affectively colored, self-transcending subject-object relationship in which cognitive processing is felt to flow differently than during everyday experiences. Notwithstanding previous multidisciplinary investigations, how esthetic experience modulates perception is still obscure. We used Arcimboldo's ambiguous portraits to assess how the esthetic context organizes ambiguous percepts. The study was carried out using functional magnetic resonance imaging (fMRI) in healthy young volunteers (mean age 25.45; S.D. 4.51; 9 females), during both an explicit esthetic judgment task and an artwork/non-artwork classification task. We show that a distinct neural mechanism in the fusiform gyrus contributes to the esthetic experience of ambiguous portraits, according to the valence of the esthetic experience. Ambiguous artworks eliciting a negative esthetic experience lead to more pronounced activation of the fusiform face areas than ambiguous artworks eliciting a positive esthetic experience. We also found an interaction between task and ambiguity in the right superior parietal lobule. Taken together, our results demonstrate that a neural mechanism in the content-dependent brain regions of face processing underlies the esthetic experience of ambiguous portraits. Furthermore, they suggest that esthetic experience interacts with perceptual qualities of stimuli in the right superior parietal lobe, supporting the idea that esthetic experience arises from the interaction between top-down orienting of attention and bottom-up perceptual facilitation. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Esthetic perception of orthodontic appliances by Brazilian children and adolescents.

    Science.gov (United States)

    Kuhlman, Deise Caldas; Lima, Tatiana Araújo de; Duplat, Candice Belchior; Capelli, Jonas

    2016-01-01

    The objective of this present study was to understand how children and adolescents perceive esthetic attractiveness of a variety of orthodontic appliances. It also analyzed preferences according to patients' age, sex and socioeconomic status. A photograph album consisting of eight photographs of different orthodontic appliances and clear tray aligners placed in a consenting adult with pleasing smile was used. A sample of children or adolescents aged between 8 and 17 years old (n = 276) was asked to rate each image for its attractiveness on a visual analog scale. Comparisons between the appliances attractiveness were performed by means of nonparametric statistics with Friedman's test followed by Dunn's multiple comparison post-hoc test. Correlation between appliances and individuals' socioeconomic status, age, sex, and esthetic perception was assessed by means of Spearman's correlation analysis. Attractiveness ratings of orthodontic appliances varied nonsignificantly for children in the following hierarchy: traditional metallic brackets with green elastomeric ligatures > traditional metallic brackets with gray elastomeric ligatures > sapphire esthetic brackets; and for adolescents, as follows: sapphire esthetic brackets > clear aligner without attachments > traditional metallic brackets with green elastomeric ligatures. The correlation between individuals' socioeconomic status and esthetic perception of a given appliance was negative and statistically significant for appliances such as the golden orthodontic brackets and traditional metallic brackets with green elastomeric ligatures. Metal appliances were considered very attractive, whereas aligners were classified as less attractive by children and adolescents. The correlation between esthetic perception and socioeconomic status revealed that individuals with a higher socioeconomic level judged esthetics as the most attractive attribute. For those with higher economic status, golden orthodontic brackets and

  20. Esthetic outcome for maxillary anterior single implants assessed by different dental specialists.

    Science.gov (United States)

    Al-Dosari, Abdullah; Al-Rowis, Ra'ed; Moslem, Feras; Alshehri, Fahad; Ballo, Ahmed M

    2016-10-01

    The aim of this study was to assess the esthetic outcome of maxillary anterior single implants by comparing the esthetic perception of dental professionals and patients. Twenty-three patients with single implants in the esthetic zone were enrolled in this study. Dentists of four different dental specialties (Three orthodontists, three oral surgeons, three prosthodontists, and three periodontists) evaluated the pink esthetic score (PES)/white esthetic score (WES) for 23 implant-supported single restorations. The satisfactions of the patients on the esthetic outcome of the treatment have been evaluated according to the visual analog scale (VAS). The mean total PES/WES was 12.26 ± 4.76. The mean PES was 6.45 ± 2.78 and mean WES was 5.80 ± 2.82. There was a statistically significant difference among the different specialties for WES ( P esthetic perception, thereby providing rationales for involving patients in the treatment plan to achieve higher levels of patient satisfaction.

  1. Estimating physical activity in children: impact of pedometer wear time and metric.

    Science.gov (United States)

    Laurson, Kelly R; Welk, Gregory J; Eisenmann, Joey C

    2015-01-01

    The purpose of this study was to provide a practical demonstration of the impact of monitoring frame and metric when assessing pedometer-determined physical activity (PA) in youth. Children (N = 1111) were asked to wear pedometers over a 7-day period during which time worn and steps were recorded each day. Varying data-exclusion criteria were used to demonstrate changes in estimates of PA. Steps were expressed using several metrics and criteria, and construct validity was demonstrated via correlations with adiposity. Meaningful fluctuations in average steps per day and percentage meeting PA recommendations were apparent when different criteria were used. Children who wore the pedometer longer appeared more active, with each minute the pedometer was worn each day accounting for an approximate increase of 11 and 8 steps for boys and girls, respectively (P < .05). Using more restrictive exclusion criteria led to stronger correlations between indices of steps per day, steps per minute, steps per leg length, steps per minute per leg length, and obesity. Wear time has a meaningful impact on estimates of PA. This should be considered when determining exclusion criteria and making comparisons between studies. Results also suggest that incorporating wear time per day and leg length into the metric may increase validity of PA estimates.

  2. Use of nuclear techniques for measuring thin wears

    International Nuclear Information System (INIS)

    Jeanneau, B.

    1989-01-01

    Wear measurements with apparatus of classical metrology like profilography or tridimensional analysis, need a certain number of conditions, in particular, dismantling of the machine into parts, which give less of time and money. Radioactive methods permit to avoid such a dismantling, isn't sensitive to the temperature of the part... and according to their sensitivity, reduce the test duration

  3. Influence of the Operational Wear of the Stator Parts of Shroud Seals on the Economic Efficiency of the Steam Turbines

    Science.gov (United States)

    Kostyuk, A. G.; Dmitriev, S. S.; Petrunin, B. N.; Gusev, A. A.

    2018-01-01

    increase approximately 1.7 times slower than under the similar wear of the ridges of conventional straight-through seals with smooth stator parts. However, this gain in efficiency achieved by replacing the standard smooth-wall seals with the honeycomb seals must be necessarily correlated with the measurement data on the nonconservative shroud forces in conventional axial-radial seals with smooth stator surfaces with a radial clearance of 4 mm, which is almost seven times lower than that in the honeycomb seals with a radial clearance of 0.5 mm. From the results obtained in the work, it follows that the installation of honeycomb shroud seals instead of traditional ridge seals in the high-pressure cylinders (HPCs) of the steam turbines for subcritical steam parameters with high-vibration-resistance rotors that have a sufficient margin of resistance to self-oscillations is undoubtedly advisable from the point of view of increasing the economic efficiency of the turbines. However, the use of honeycomb shroud seals with reduced radial clearances in the HPC parts of the steam turbines for supercritical steam parameters requires special cautiousness, since it is in the area of small clearances that the maximum nonconservative shroud forces capable of causing auto-oscillations of the shafting are observed and these forces are maximal precisely at high pressures.

  4. Diagnosis and management of maxillary incisors affected by incisal wear: an interdisciplinary case report.

    Science.gov (United States)

    Bernardo, Jussara Karina; Maia, Elaine A Vilela; Cardoso, Antônio Carlos; de Araújo Júnior, Edson Medeiros; Monteiro Júnior, Sylvio

    2002-01-01

    In the attempt to restore anterior teeth affected by erosion and bruxism, many clinicians have been frustrated with the constant restorative failures. Frequently, these failures are attributed to the restorative materials employed, especially in cases in which composite resins are used. However, some flaws of the restorations are related to the oversight of occlusal principles. The purpose of this article is to discuss the etiology, signs, and symptoms of incisal wear, with special attention to that caused by bruxism and chemical erosion. Relatively simple management techniques (e.g., occlusal adjustment, adhesive restorations) are proposed, and the diagnosis and management of a representative clinical case is presented. In some cases of bruxism and/or dental erosion, it is possible to acquire space to recuperate the esthetics and function of maxillary incisors affected by incisal wear through a conservative treatment associated with the control of the etiologic factors.

  5. Esthetic perception of orthodontic appliances by Brazilian children and adolescents

    Science.gov (United States)

    Kuhlman, Deise Caldas; de Lima, Tatiana Araújo; Duplat, Candice Belchior; Capelli, Jonas

    2016-01-01

    ABSTRACT Objective: The objective of this present study was to understand how children and adolescents perceive esthetic attractiveness of a variety of orthodontic appliances. It also analyzed preferences according to patients' age, sex and socioeconomic status. Methods: A photograph album consisting of eight photographs of different orthodontic appliances and clear tray aligners placed in a consenting adult with pleasing smile was used. A sample of children or adolescents aged between 8 and 17 years old (n = 276) was asked to rate each image for its attractiveness on a visual analog scale. Comparisons between the appliances attractiveness were performed by means of nonparametric statistics with Friedman's test followed by Dunn's multiple comparison post-hoc test. Correlation between appliances and individuals' socioeconomic status, age, sex, and esthetic perception was assessed by means of Spearman's correlation analysis. Results: Attractiveness ratings of orthodontic appliances varied nonsignificantly for children in the following hierarchy: traditional metallic brackets with green elastomeric ligatures > traditional metallic brackets with gray elastomeric ligatures > sapphire esthetic brackets; and for adolescents, as follows: sapphire esthetic brackets > clear aligner without attachments > traditional metallic brackets with green elastomeric ligatures. The correlation between individuals' socioeconomic status and esthetic perception of a given appliance was negative and statistically significant for appliances such as the golden orthodontic brackets and traditional metallic brackets with green elastomeric ligatures. Conclusion: Metal appliances were considered very attractive, whereas aligners were classified as less attractive by children and adolescents. The correlation between esthetic perception and socioeconomic status revealed that individuals with a higher socioeconomic level judged esthetics as the most attractive attribute. For those with higher

  6. Esthetic perception of orthodontic appliances by Brazilian children and adolescents

    Directory of Open Access Journals (Sweden)

    Deise Caldas Kuhlman

    Full Text Available ABSTRACT Objective: The objective of this present study was to understand how children and adolescents perceive esthetic attractiveness of a variety of orthodontic appliances. It also analyzed preferences according to patients' age, sex and socioeconomic status. Methods: A photograph album consisting of eight photographs of different orthodontic appliances and clear tray aligners placed in a consenting adult with pleasing smile was used. A sample of children or adolescents aged between 8 and 17 years old (n = 276 was asked to rate each image for its attractiveness on a visual analog scale. Comparisons between the appliances attractiveness were performed by means of nonparametric statistics with Friedman's test followed by Dunn's multiple comparison post-hoc test. Correlation between appliances and individuals' socioeconomic status, age, sex, and esthetic perception was assessed by means of Spearman's correlation analysis. Results: Attractiveness ratings of orthodontic appliances varied nonsignificantly for children in the following hierarchy: traditional metallic brackets with green elastomeric ligatures > traditional metallic brackets with gray elastomeric ligatures > sapphire esthetic brackets; and for adolescents, as follows: sapphire esthetic brackets > clear aligner without attachments > traditional metallic brackets with green elastomeric ligatures. The correlation between individuals' socioeconomic status and esthetic perception of a given appliance was negative and statistically significant for appliances such as the golden orthodontic brackets and traditional metallic brackets with green elastomeric ligatures. Conclusion: Metal appliances were considered very attractive, whereas aligners were classified as less attractive by children and adolescents. The correlation between esthetic perception and socioeconomic status revealed that individuals with a higher socioeconomic level judged esthetics as the most attractive attribute. For those

  7. Esthetic rhinoplasty as an adjunctive technique in nasal oncoplastic ...

    African Journals Online (AJOL)

    Adham Farouk

    2016-01-15

    Jan 15, 2016 ... Esthetic rhinoplasty;. Oncoplastic surgery nose;. Basal cell carcinoma;. Squamous cell carcinoma;. Nonmelanoma skin cancer;. Nasal reconstruction ... Conclusions: Esthetic rhinoplasty is a useful adjunctive technique in nasal oncoplastic surgery. .... All procedures performed in the study involving human.

  8. Smile esthetics: calculated beauty?

    Science.gov (United States)

    Lecocq, Guillaume; Truong Tan Trung, Lisa

    2014-06-01

    Esthetic demand from patients continues to increase. Consequently, the treatments we offer are moving towards more discreet or invisible techniques using lingual brackets in order to achieve harmonious, balanced results in line with our treatment goals. As orthodontists, we act upon relationships between teeth and bone. And the equilibrium they create impacts the entire face via the smile. A balanced smile is essential to an esthetic outcome and is governed by rules, which guide both the practitioner and patient. A smile can be described in terms of mathematical ratios and proportions but beauty cannot be calculated. For the smile to sit harmoniously within the face, we need to take into account facial proportions and the possibility of their being modified by our orthopedic appliances or by surgery. Copyright © 2014 CEO. Published by Elsevier Masson SAS. All rights reserved.

  9. Gingival-colored Porcelain: A Clinical Report of an Esthetic-prosthetic Paradigm.

    Science.gov (United States)

    Sonune, Shital Jalandar; Kumar, Shiv; Jadhav, Manish Shivaji; Martande, Santosh

    2017-01-01

    Traditionally, periodontics has been instrumental in treating hard- and soft-tissue defect. Surgical and regenerative periodontal procedures can reconstruct the three-dimensional architecture of the hard- and soft-tissue defect. However, at times, these invasive procedures leave the patients with an esthetic problem. In such situations, the defects can be treated by the prosthetic approach. A predictable esthetically pleasing and functional outcome without any surgical procedure is being a choice of treatment for many. This article discusses about the treatment for the defect of excessive hard and soft tissue, using porcelain fused to a metal restoration with gingival-colored porcelain for both tooth-supported and implant-supported fixed prosthesis.

  10. Gingival-colored Porcelain: A Clinical Report of an Esthetic-prosthetic Paradigm

    Science.gov (United States)

    Sonune, Shital Jalandar; Kumar, Shiv; Jadhav, Manish Shivaji; Martande, Santosh

    2017-01-01

    Traditionally, periodontics has been instrumental in treating hard- and soft-tissue defect. Surgical and regenerative periodontal procedures can reconstruct the three-dimensional architecture of the hard- and soft-tissue defect. However, at times, these invasive procedures leave the patients with an esthetic problem. In such situations, the defects can be treated by the prosthetic approach. A predictable esthetically pleasing and functional outcome without any surgical procedure is being a choice of treatment for many. This article discusses about the treatment for the defect of excessive hard and soft tissue, using porcelain fused to a metal restoration with gingival-colored porcelain for both tooth-supported and implant-supported fixed prosthesis. PMID:29308371

  11. Wear studies of engine components using neutron activation techniques

    International Nuclear Information System (INIS)

    Banados Perez, H.E.; Carvalho, G.; Daltro, T.F.L.

    1984-01-01

    The results obtained in a series of tests for determining the wearing rate of some diesel engine components are reported. The pieces investigated were the needles of fuel injection nozzles, that were previously irradiated with a 10 13 nv in the IEA-R1 nuclear reactor, and the wearing rate was established for different types of fuels. Total wear was calculated by measuring the specific activity of 51 Cr present in the fuel and originated by metal particles worn from the needle. Wear were performed using a device that simulated the actual working conditions of the injection nozzles. The system was run during 350 hours and, along that period, 36 fuel samples of 10 ml each, were collected and analysed for cumulative wear calculation. A metal concentration as low as 10- 6 g in 10 ml of fuel sample could be measured by this method. At present time this procedure is being applied for measuring the wear-rate of other nozzle parts, using localized neutron activation techiques. (Author) [pt

  12. Millisecond bearing wear

    International Nuclear Information System (INIS)

    Blatchley, C.; Sioshansi, P.

    1987-01-01

    Radionuclides have been widely used for many purposes in medicine, metals, transportation, manufacturing and research. Approximately 200 artificially produced nuclides are commercially available from reactors or accelerator sources. Another 400 or so have properties which may make them useful if satisfactory methods of production can be developed. One of the most economically important industrial applications of radionuclides has been in wear measurement and condition monitoring in reciprocating engines. The general techniques developed for this purpose have also been applied in a number of other areas besides engine or lubrication studies. The wear of floor wax applied to linoleum, for example, has been measured by mixing shortlived radionuclides in the wax. In those applications where the material is tagged and then followed, the radionuclides are termed ''tracers,'' similar to the medical tracer materials used to measure uptake or metabolism of biologically active chemicals in the body. The alternate function for the radionuclides is to act as ''markers'' which indicate the amount of material which is remaining at the location of the original activation. Both approaches require that the debris removed from the surface must be carried away from the original site. The first application of radioactive tracers as a diagnostic tool in engines was in 1949. In this technique, an entire wearing part such as a piston ring or gear was first exposed to neutrons in a nuclear reactor. This caused the entire volume of the part to become radioactive. The part was next installed and exposed to wear in the operating engine. Detectors placed near the oil line, an oil filter or a sediment trap then determined the amount of debris from the part by counting the gamma rays escaping from the debris

  13. Perception of Laypeople and Dental Professionals of Smile Esthetics

    Directory of Open Access Journals (Sweden)

    Aida Saffarpour

    2016-10-01

    Full Text Available Objectives: This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth.Materials and Methods: A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS chart for scoring (1-10. After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test.Results: No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc.Conclusions: Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments.Keywords: Smiling; Perception; Esthetics, Dental

  14. Reproducibility of the pink esthetic score--rating soft tissue esthetics around single-implant restorations with regard to dental observer specialization.

    Science.gov (United States)

    Gehrke, Peter; Lobert, Markus; Dhom, Günter

    2008-01-01

    The pink esthetic score (PES) evaluates the esthetic outcome of soft tissue around implant-supported single crowns in the anterior zone by awarding seven points for the mesial and distal papilla, soft-tissue level, soft-tissue contour, soft-tissue color, soft-tissue texture, and alveolar process deficiency. The aim of this study was to measure the reproducibility of the PES and assess the influence exerted by the examiner's degree of dental specialization. Fifteen examiners (three general dentists, three oral maxillofacial surgeons, three orthodontists, three postgraduate students in implant dentistry, and three lay people) applied the PES to 30 implant-supported single restorations twice at an interval of 4 weeks. Using a 0-1-2 scoring system, 0 being the lowest, 2 being the highest value, the maximum achievable PES was 14. At the second assessment, the photographs were scored in reverse order. Differences between the two assessments were evaluated with the Spearman's rank correlation coefficient (R). The Wilcoxon signed-rank test was used for comparisons of differences between the ratings. A significance level of p esthetic restorations showed the smallest deviations. Orthodontists were found to have assigned significantly poorer ratings than any other group. The assessment of postgraduate students and laypersons were the most favorable. The PES allows for a more objective appraisal of the esthetic short- and long-term results of various surgical and prosthetic implant procedures. It reproducibly evaluates the peri-implant soft tissue around single-implant restorations and results in good intra-examiner agreement. However, an effect of observer specialization on rating soft-tissue esthetics can be shown.

  15. The validity of compliance monitors to assess wearing time of thoracic-lumbar-sacral orthoses in children with spinal cord injury.

    Science.gov (United States)

    Hunter, Louis N; Sison-Williamson, Mitell; Mendoza, Melissa M; McDonald, Craig M; Molitor, Fred; Mulcahey, M J; Betz, Randal R; Vogel, Lawrence C; Bagley, Anita

    2008-06-15

    Prospective multicenter observation. To determine the validity of 3 commercially available at recording thoracic-lumbar-sacral orthosis (TLSO) wearing time of children with spinal cord injury (SCI) and to assess each monitor's function during daily activities. A major limitation to studies assessing the effectiveness of spinal prophylactic bracing is the patient's compliance with the prescribed wearing time. Although some studies have begun to use objective compliance monitors, there is little documentation of the validity of the monitors during activities of daily life and no comparisons of available monitors. Fifteen children with SCI who wore a TLSO for paralytic scoliosis were observed for 4 days during their rehabilitation stay. Three compliance monitors (2 temperature and 1 pressure sensitive) were mounted onto each TLSO. Time of brace wear from the monitors was compared with the wear time per day recorded in diaries. Observed versus monitored duration of brace wear found the HOBO (temperature sensitive) to be the most valid compliance monitor. The HOBO had the lowest average of difference and variance of difference scores. The correlation between the recorded daily entries and monitored brace wear time was also highest for the HOBO in analysis of dependent and independent scores. Bland-Altman plots showed that the pressure sensitive monitor underestimated wear time whereas the temperature monitors overestimated wear time. Compliance to prescribed wearing schedule has been a barrier to studying TLSO efficacy. All 3 monitors were found to measure TLSO compliance, but the 2 temperature monitors were more in agreement with the daily diaries. Based on its functional advantages compared with the HOBO, the StowAway TidbiT will be used to further investigate the long-term compliance of TLSO bracing in children with SCI.

  16. Implant therapy in the esthetic zone: smile line assessment.

    Science.gov (United States)

    Kourkouta, Stella

    2011-04-01

    Assessment of the smile or lip line is imperative when implant therapy is carried out in the esthetic zone. The smile is generally defined as high, average, or low. Females are reported to have higher lip lines than males, which means that they are at greater risk when placing and restoring implants in the esthetic zone. Maximum upper lip elevation, usually observed during a strained posed smile, should be assessed. This paper discusses some clinical observations and concepts in relation to smile line assessment for implant therapy in the esthetic zone. (Int J Periodontics Restorative Dent 2011;31:195-201.).

  17. Evaluation of mechanical properties of esthetic brackets

    OpenAIRE

    Matsui, Shigeyuki; Umezaki, Eisaku; Komazawa, Daigo; Otsuka, Yuichiro; Suda, Naoto

    2015-01-01

    Plastic brackets, as well as ceramic brackets, are used in various cases since they have excellent esthetics. However, their mechanical properties remain uncertain. The purpose of this study was to determine how deformation and stress distribution in esthetic brackets differ among materials under the same wire load. Using the digital image correlation method, we discovered the following: (1) the strain of the wings of plastic brackets is within 0.2% and that of ceramic and metal brackets is n...

  18. Optimizing the Esthetics of peg-shaped teeth

    OpenAIRE

    Fabia Danielle Sales da Cunha Medeiros e Silva; Rosângela Marques Duarte; Ana Karina Maciel Andrade; Ricardo Jorge Alves Figueiredo

    2008-01-01

    In modern esthetic dentistry, recontouring peg-shaped teeth present the option of a technique for obtaining a harmonious smile. In thiscontext, the advancement of direct dental materials, such as resin composites and adhesive systems, allows this procedure to be performedsimply and efficiently, when compared with other available techniques. Thus, the aim of this report is to present a clinical case with an esthetic solution in peg-shaped lateral incisors (12 and 22). Initially, it was opted f...

  19. Wear resistance of layers hard faced by the high-alloyed filler metal

    Directory of Open Access Journals (Sweden)

    Dušan Arsić

    2016-10-01

    Full Text Available The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by high hardness and wear resistance. In experiments, the sliding speed and the normal loading were varied and the wear scar was monitored, based on which the volume of the worn material was calculated analytically. The contact duration time was monitored over the sliding path of 300 mm. The most intensive wear was established for the loading force of 100 N and the sliding speed of 1 m.s-1, though the significant wear was also noticed in conditions of the small loading and speed of 0.25 m.s-1, which was even greater that at larger speeds.

  20. Ethnicity and perception of dental shade esthetics.

    Science.gov (United States)

    Niaz, Muhammad Omar; Naseem, Mustafa; Elcock, Claire

    2015-01-01

    To determine whether or not people from different ethnic backgrounds have different attitudes towards dental esthetics and chose different dental appearances in terms of tooth shade, and to determine whether the dental professional's choice and the individual's own choice have any relationship with what the individual ideally perceives as esthetically pleasing. For this cross-sectional analytical study, 120 volunteer students from the University of Sheffield (excepting dental students) from various ethnic backgrounds, of different ages, of both genders, and with varying degree/educational levels were recruited from the campus. The volunteers were asked to complete a questionnaire containing 9 adapted attitudinal statements regarding positive or negative dental esthetic perceptions in terms of tooth shade, with responses on a 5-point Likert scale from "Entirely agree" to "Entirely disagree". Scores for all attitudinal statements were summed up to give an attitudinal score. The participants' ideal, perceived, and actual (self-assessed and investigatorassessed) tooth shade was also determined using a shade guide and a facial mirror. No association between ethnicity and attitudinal score was found. However, statistically significant associations were found between the participants' degree/educational level (P=0.004, 95% Confidence Interval (CI)=-4.18 to -0.82) and their ideal tooth shade value (P=0.038, 95% CI=-3.53 to -0.11). There were strong correlations between self-assessed and professionally assessed tooth shade value in all ethnic groups, with Spearman's rank correlation coefficient (rho) being ρ>0.6. Regarding ideally desired and perceived tooth shade value, weak correlations were found in all ethnic groups (Spearman's rho being ρethnicity and attitude towards dental esthetics with regard to tooth shade, both ethnicity and dental esthetics are very diverse terms with multiple dimensions, each of which needs further investigation with regard to their mutual

  1. What women like: influence of motion and form on esthetic body perception

    Directory of Open Access Journals (Sweden)

    Valentina eCazzato

    2012-07-01

    Full Text Available Several studies have shown the distinct contribution of motion and form to the esthetic evaluation of female bodies. Here, we investigated how variations of implied motion and body size interact in the esthetic evaluation of female and male bodies in a sample of young healthy women. Participants provided attractiveness, beauty, and liking ratings for the shape and posture of virtual renderings of human bodies with variable body size and implied motion. The esthetic judgments for both shape and posture of human models were influenced by body size and implied motion, with a preference for thinner and more dynamic stimuli. Implied motion, however, attenuated the impact of extreme body size on the esthetic evaluation of body postures, and body size variations did not affect the preference for more dynamic stimuli. Results show that body form and action cues interact in esthetic perception, but the final esthetic appreciation of human bodies is predicted by a mixture of perceptual and affective evaluative components.

  2. Removable gingival epithesis: esthetic and quick alternative resolution for anterior periodontal tissue replacement

    Directory of Open Access Journals (Sweden)

    Cátia Maria Fonseca Guerral

    2008-01-01

    Full Text Available The gingiva, part of the masticatory mucosa tissue that covers the alveolar process and surrounds the cervical portion of teeth, has a definitive shape and texture associated with the eruption of teeth. Therefore, it must be included in rehabilitative planning, as the absence of papillae induces problems with esthetics, phonetics and food-impaction. The purpose of the present study was to approach the indications, limitations and techniques for making a removable artificial gingiva made of acrylic resin, by reporting on a clinical case. The patient, a 29-year-old woman, with the sequelae of periodontal disease, presented loss of interdental papilla causing “black holes”. She was dissatisfied with the esthetic appearance of her teeth, and also complained of long teeth and air escaping when she spoke. As treatment, prosthetic reconstruction was proposed, by means of a removable artificial gingiva (gingival epithesis to simulate the presence of interdental papillae, providing better esthetics and phonetics. Gingival epithesis is an easily made, inserted and hygienically cleaned appliance that provides a simple and safe alternative solution for cases in which surgical techniques are limited.

  3. Andrew′s Bridge System: An Esthetic Option

    Directory of Open Access Journals (Sweden)

    Prajakta Bhapkar

    2015-01-01

    Full Text Available Loss of teeth often results in loss of a variable amount of adjacent soft and hard tissue. Complete esthetic surgical replacement of the lost tissues is difficult and unpredictable, particularly when a greater degree of the residual ridge has been lost due to trauma, congenital defects or other pathologic process. Fixed-removable partial dentures are particularly indicated for patients with extensive supportive tissue loss and when the alignment of the opposing arches and/or esthetic arch position of the replacement teeth create difficulties for placement of a conventional fixed partial denture. This case report shows the fabrication of a fixed-removable partial denture using the Andrews Bridge philosophy wherein a removable prosthesis is retained by a bar and sleeve attachment to fixed retainers on the either side of the edentulous space. This prosthesis is designed to meet the requirements for esthetics, comfort, phonetics, hygiene, and favorable stress distribution to the abutments and soft tissue.

  4. Optimizing the Esthetics of peg-shaped teeth

    Directory of Open Access Journals (Sweden)

    Fabia Danielle Sales da Cunha Medeiros e Silva

    2008-01-01

    Full Text Available In modern esthetic dentistry, recontouring peg-shaped teeth present the option of a technique for obtaining a harmonious smile. In thiscontext, the advancement of direct dental materials, such as resin composites and adhesive systems, allows this procedure to be performedsimply and efficiently, when compared with other available techniques. Thus, the aim of this report is to present a clinical case with an esthetic solution in peg-shaped lateral incisors (12 and 22. Initially, it was opted first to perform dental bleaching with a home bleaching gel (16% carbamide peroxide associated with an acetate mold duly made for this purpose. The peg-shaped teeth were recontoured with a microhybrid resin composite (shade EA1 and DA1 with the aid of a platinum guide in silicone, obtained after diagnostic waxing on the plaster model. It was concluded that the association of esthetic procedures is of the utmost importance for obtaining good looking, aligned and harmonious teeth.

  5. A Conservative Esthetic Approach Using Enamel Recontouring and Composite Resin Restorations

    OpenAIRE

    Mathias, Paula; da Silva, Emily Vivianne Freitas; Aguiar, Thaiane Rodrigues; Andrade, Aline Silva; Azevedo, Juliana

    2016-01-01

    Conservative clinical solutions, predictable esthetic, and immediate outcomes are important concepts of restorative dentistry. The aim of this case study was to recognize the selective enamel removal as an interesting conservative alternative to achieve optimal esthetic results and discuss the clinical protocol. This clinical report described an alternative esthetic and conservative treatment to transform the long and sharp aspect of the maxillary canines with a slightly aggressive aspect int...

  6. Shaping the breast in secondary microsurgical breast reconstruction: single- vs. two-esthetic unit reconstruction.

    Science.gov (United States)

    Gravvanis, Andreas; Smith, Roger W

    2010-10-01

    The esthetic outcome is dictated essentially not only by the position, size, and shape of the reconstructed breast, but also by the extra scaring involved. In the present study, we conducted a visual analog scale survey to compare the esthetic outcome in delayed autologous breast reconstruction following two different abdominal flaps inset. Twenty-five patients had their reconstruction using the Single-esthetic Unit principle and were compared with 25 patients that their breast was reconstructed using the Two-Esthetic Unit principle. Photographic images were formulated to a PowerPoint presentation and cosmetic outcomes were assessed from 30 physicians, by means of a Questionnaire and a visual analog scale. Our data showed that the single-esthetic unit breast reconstruction presents significant advantages over the traditional two-esthetic units, due to inconspicuous flap reconstruction, better position of the inframammary fold, and more natural transition from native and reconstructed tissues. Moreover, patient self-evaluation of esthetic outcome and quality of life showed that single-esthetic unit reconstruction is associated with higher patient satisfaction, therefore should be considered the method of choice. © 2010 Wiley-Liss, Inc.

  7. Esthetic Evaluation of Anterior Single-Tooth Implants with Different Abutment Designs-Patients' Satisfaction Compared to Dentists' Observations.

    Science.gov (United States)

    Patil, Ratnadeep; Gresnigt, Marco M M; Mahesh, Kavita; Dilbaghi, Anjali; Cune, Marco S

    2017-07-01

    To correlate patients' satisfaction and dentists' observations regarding two abutment designs used for single crowns in the esthetic zone: a divergent one (control) and a curved one (experimental), with special emphasis on muco-gingival esthetics. Twenty-six patients with nonadjacent missing teeth in the esthetic zone were enrolled in a randomized clinical trial (within-subject comparison). Two implants placed in each were restored using abutments of different geometry. Patients' appreciation was assessed on a visual analog scale (VAS) by recording answers to three questions, and dentists' appreciation was determined by means of the Pink Esthetic Score (PES) at T0 (crown cementation, baseline) and at T12 (1 year post-cementation). ANOVA with post hoc analysis was used to identify differences between groups and at different moments in time. Pearson correlations were calculated between all variables, both at T0 and at T12. No statistically significant differences were found at any time between the control and experimental abutment design, either for the PES or for the VAS score. PES slightly improved after 1 year, as did the VAS rating related to functioning with the implant-crown compared to the natural teeth. All PES and VAS scores demonstrated highly significant correlation. Both patient satisfaction and professional appreciation of muco-gingival conditions after single implant treatment in the esthetic zone were high; however, the curved, experimental abutment design performed no better than the conventional, divergent type. Curved abutment design does not significantly impact crown or gingival esthetics as assessed by PES and VAS scored by dentists and patients, respectively. © 2016 by the American College of Prosthodontists.

  8. Soft Tissue Surgical Procedures for Optimizing Anterior Implant Esthetics

    Science.gov (United States)

    Ioannou, Andreas L.; Kotsakis, Georgios A.; McHale, Michelle G.; Lareau, Donald E.; Hinrichs, James E.; Romanos, Georgios E.

    2015-01-01

    Implant dentistry has been established as a predictable treatment with excellent clinical success to replace missing or nonrestorable teeth. A successful esthetic implant reconstruction is predicated on two fundamental components: the reproduction of the natural tooth characteristics on the implant crown and the establishment of soft tissue housing that will simulate a healthy periodontium. In order for an implant to optimally rehabilitate esthetics, the peri-implant soft tissues must be preserved and/or augmented by means of periodontal surgical procedures. Clinicians who practice implant dentistry should strive to achieve an esthetically successful outcome beyond just osseointegration. Knowledge of a variety of available techniques and proper treatment planning enables the clinician to meet the ever-increasing esthetic demands as requested by patients. The purpose of this paper is to enhance the implant surgeon's rationale and techniques beyond that of simply placing a functional restoration in an edentulous site to a level whereby an implant-supported restoration is placed in reconstructed soft tissue, so the site is indiscernible from a natural tooth. PMID:26124837

  9. A method for increase abrasive wear resistance parts by obtaining on methods casting on gasifying models

    Science.gov (United States)

    Sedukhin, V. V.; Anikeev, A. N.; Chumanov, I. V.

    2017-11-01

    Method optimizes hardening working layer parts’, working in high-abrasive conditions looks in this work: bland refractory particles WC and TiC in respect of 70/30 wt. % prepared by beforehand is applied on polystyrene model in casting’ mould. After metal poured in mould, withstand for crystallization, and then a study is carried out. Study macro- and microstructure received samples allows to say that thickness and structure received hardened layer depends on duration interactions blend harder carbides and liquid metal. Different character interactions various dispersed particles and matrix metal observed under the same conditions. Tests abrasive wear resistance received materials of method calculating residual masses was conducted in laboratory’ conditions. Results research wear resistance showed about that method obtaining harder coating of blend carbide tungsten and carbide titanium by means of drawing on surface foam polystyrene model before moulding, allows receive details with surface has wear resistance in 2.5 times higher, than details of analogy steel uncoated. Wherein energy costs necessary for transformation units mass’ substances in powder at obtained harder layer in 2.06 times higher, than materials uncoated.

  10. The assessment of dentofacial esthetics in restorative dentistry: a review of the literature.

    Science.gov (United States)

    Frese, Cornelia; Staehle, Hans Joerg; Wolff, Diana

    2012-05-01

    The authors conducted a literature review to determine how dentofacial esthetics can be evaluated in restorative dentistry and which quantifiable clinical parameters can be used for this assessment of dentofacial esthetics. The authors selected 35 studies that focused on assessment strategies for dental professionals. The primary inclusion criteria were intraoral and extraoral esthetic assessment methods and indexes or rating scales evaluating esthetics in restorative dentistry. The studies' protocols and assessment methods were heterogeneous. The authors grouped the studies into six categories according to topic: golden proportion, soft-tissue measurement, smile and smile line assessment, orofacial indexes and scales, incisor proportion and angulation, and facial esthetics. These categories included various esthetic parameters, including the smile line, lip line, incisal offset, location of dental and facial midline, incisor angulations and width to height ratios of the maxillary anterior teeth, gingival contour, and root coverage and papilla height. These parameters should be considered when providing dental treatment in the anterior area, as they allow for quantification and objective judgment. The findings of this review might increase interest in a comprehensive dental esthetic index that allows for objective quantification and intrastudy and interstudy comparison of dental treatment outcomes.

  11. Esthetic evaluation of single-tooth implants in the anterior maxilla following autologous bone augmentation.

    Science.gov (United States)

    Hof, M; Pommer, B; Strbac, G D; Sütö, D; Watzek, G; Zechner, W

    2013-08-01

    Autologous bone augmentation to rebuild compromised alveolar ridge contour prior to implant placement allows for favorable three-dimensional implant positioning to achieve optimum implant esthetics. The aim of the present study was to evaluate peri-implant soft tissue conditions around single-tooth implants following bone grafts in the esthetic zone of the maxilla. Sixty patients underwent autologous bone augmentation of deficient maxillary sites prior to placement of 85 implants in the esthetic zone. In case of multiple implants per patient, one implant was randomly selected. Objective evaluation of 60 single-tooth implants was performed using the Pink-Esthetic-Score (PES) and Papilla Index (PI) and supplemented by subjective patient evaluation, as well as clinical and radiologic examination. Objective ratings of implant esthetics were satisfactory (median PES: 11, median PI: 2) and significantly correlated with high patient satisfaction (mean VAS score: 80%). Both esthetic indices demonstrated respectable levels of inter- as well as intra-observer agreement. Poor implant esthetics (low PES and PI ratings) were significantly associated with increased anatomic crown height, while no influence of horizontal implant-tooth distance could be found. The present investigation indicates that favorable esthetic results may be achieved in the augmented anterior maxilla. However, bony reconstruction of compromised alveolar ridges does not guarantee optimum implant esthetics. © 2011 John Wiley & Sons A/S.

  12. Wear and breakage monitoring of cutting tools by an optical method: theory

    Science.gov (United States)

    Li, Jianfeng; Zhang, Yongqing; Chen, Fangrong; Tian, Zhiren; Wang, Yao

    1996-10-01

    An essential part of a machining system in the unmanned flexible manufacturing system, is the ability to automatically change out tools that are worn or damaged. An optoelectronic method for in situ monitoring of the flank wear and breakage of cutting tools is presented. A flank wear estimation system is implemented in a laboratory environment, and its performance is evaluated through turning experiments. The flank wear model parameters that need to be known a priori are determined through several preliminary experiments, or from data available in the literature. The resulting cutting conditions are typical of those used in finishing cutting operations. Through time and amplitude domain analysis of the cutting tool wear states and breakage states, it is found that the original signal digital specificity (sigma) 2x and the self correlation coefficient (rho) (m) can reflect the change regularity of the cutting tool wear and break are determined, but which is not enough due to the complexity of the wear and break procedure of cutting tools. Time series analysis and frequency spectrum analysis will be carried out, which will be described in the later papers.

  13. Perception of Laypeople and Dental Professionals of Smile Esthetics.

    Science.gov (United States)

    Saffarpour, Aida; Ghavam, Maryam; Saffarpour, Anna; Dayani, Rozita; Fard, Mohammad Javad Kharazi

    2016-03-01

    This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth. A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran) with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS) chart for scoring (1-10). After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test. No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc. Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments.

  14. Putative golden proportions as predictors of facial esthetics in adolescents.

    NARCIS (Netherlands)

    Kiekens, R.M.A.; Kuijpers-Jagtman, A.M.; Hof, M.A. van 't; Hof, B.E. van 't; Maltha, J.C.

    2008-01-01

    INTRODUCTION: In orthodontics, facial esthetics is assumed to be related to golden proportions apparent in the ideal human face. The aim of the study was to analyze the putative relationship between facial esthetics and golden proportions in white adolescents. METHODS: Seventy-six adult laypeople

  15. Analysis of the Influence of Food Colorings in Esthetic Orthodontic Elastomeric Ligatures.

    Science.gov (United States)

    Dias da Silva, Vanessa; de Lima, Eduardo Martinelli S; Dias, Caroline; Osório, Leandro Berni

    2016-01-01

    The purpose of this study was to evaluate in vitro the color changes of esthetic orthodontic elastomeric ligatures of different shades when exposed to four food colorings commonly found in the diet of patients. The sample consisted of esthetic orthodontic elastomeric ligatures in the colors pearl, pearl blue, pearl white and colorless, which were immersed for 72 hours in five different solutions: distilled water (control group), coffee, tea, Coca-Cola ® and wine. The color changes of the esthetic orthodontic elastomeric ligatures were measured with the aid of a spectrophotometer, at T1 - as provided by the manufacturer; and T2 - after colorings process. The results indicated that the esthetic orthodontic elastomeric ligatures of all initial hues are susceptible to pigmentation. Among the evaluated colors, all changed the finished look and the color of the samples tested. In ascending order, the color of the samples was as follows: distilled water, Coca-Cola ® , black tea, wine and coffee. The substances that have a greater potential for pigmentation in esthetic orthodontic elastomeric ligatures were black tea, wine and coffee, respectively. All shades of esthetic orthodontic elastomeric ligatures are susceptible to color change.

  16. Electrophysiological brain dynamics during the esthetic judgment of human bodies and faces.

    Science.gov (United States)

    Muñoz, Francisco; Martín-Loeches, Manuel

    2015-01-12

    This experiment investigated how the esthetic judgment of human body and face modulates cognitive and affective processes. We hypothesized that judgments on ugliness and beauty would elicit separable event-related brain potentials (ERP) patterns, depending on the esthetic value of body and faces in both genders. In a pretest session, participants evaluated images in a range from very ugly to very beautiful, what generated three sets of beautiful, ugly and neutral faces and bodies. In the recording session, they performed a task consisting in a beautiful-neutral-ugly judgment. Cognitive and affective effects were observed on a differential pattern of ERP components (P200, P300 and LPC). Main findings revealed a P200 amplitude increase to ugly images, probably the result of a negativity bias in attentional processes. A P300 increase was found mostly to beautiful images, particularly to female bodies, consistent with the salience of these stimuli, particularly for stimulus categorization. LPC appeared significantly larger to both ugly and beautiful images, probably reflecting later, decision processes linked to keeping information in working memory. This finding was especially remarkable for ugly male faces. Our findings are discussed on the ground of evolutionary and adaptive value of esthetics in person evaluation. This article is part of a Special Issue entitled Hold Item. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Multi-disciplinary approach for enhancing orthodontic esthetics - case report.

    Science.gov (United States)

    Kalia, Ajit; Mirdehghan, Nasim; Khandekar, Sonali; Patil, Wasu

    2015-01-01

    In contemporary dental care, an increasing number of adult patients are now seeking orthodontic treatment with the primary motive of improvement in appearance and achievement of esthetic smile. Proper recognition of the dental and facial defects at the outset of treatment is the most important key to esthetic success and is essential in satisfying the patient's needs. By following the rules of Golden proportion smiles can be made attractive, harmonious, symmetrical, and proportionate. Consisted of 22-year-old girl who came for treatment of crowding in maxillary and mandibular arches, abnormal overjet and overbite and had unesthetic peg lateral. Non-extraction therapy was carried out since the patient had good soft tissue drape, alignment was achieved by expanding the arches and moving teeth in ideal axial inclination. Esthetic smile was attained using composite buildup of upper right peg lateral and minor adjunctive surgery (full thickness periodontal graft) on lower right central incisor. The present case report orchestrates interrelationship between various branches of dentistry and orthodontics. It exhibits how multidisciplinary approach can be used to achieve ideal dental esthetics in a 22-year-old girl who was successfully treated for peg shaped lateral incisor, gingival recession, and unesthetic smile.

  18. Striving for Normalcy after Lower Extremity Reconstruction with Free Tissue: The Role of Secondary Esthetic Refinements.

    Science.gov (United States)

    Nelson, Jonas A; Fischer, John P; Haddock, Nicholas T; Mackay, Duncan; Wink, Jason D; Newman, Andrew S; Levin, L Scott; Kovach, Stephen J

    2016-02-01

    Many patients with successful lower extremity salvage have postoperative functional and esthetic concerns. Such concerns range from contour irregularity preventing proper shoe-fitting to esthetic concerns involving color, contour, and texture match. The purpose of this study is to determine the overall incidence as well as factors associated with an increased likelihood of undergoing secondary, esthetic refinements of lower extremity free flaps and to review current revision techniques. All patients undergoing lower extremity soft tissue coverage for limb salvage procedures between January 2007 and June 2013 at a single institution were included in the analysis. Patients who underwent secondary refinements for lower extremity free flaps were compared with patients not undergoing secondary procedures. During the study period, 152 patients underwent reconstruction and were eligible for inclusion. Of these, 32 (21.1%) patients underwent secondary, esthetic revisions. Few differences in patient or case characteristics were noted, although revision patients trended toward being younger, having lower body mass index, with defects secondary to acute trauma located below the ankle. The most common revision was complex soft tissue rearrangement or surgical flap debulking/direct excision (87.5% of patients), followed by scar revision (12.5%), suction-assisted lipectomy (3.1%), laser scar revision (3.1%), and tissue expansion with local tissue rearrangement (3.1%). A significant portion of patients desire secondary revisions following the initial procedure. This is especially true of younger patients with below ankle reconstruction. In many patients, an esthetic consideration should not be of secondary concern, but should be part of the ultimate reconstructive algorithm for lower extremity limb salvage. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. Perception of Laypeople and Dental Professionals of Smile Esthetics

    Science.gov (United States)

    Saffarpour, Aida; Ghavam, Maryam; Saffarpour, Anna; Dayani, Rozita; Fard, Mohammad Javad Kharazi

    2016-01-01

    Objectives: This study aimed to assess and compare the perception of laypersons and dental professionals of smile esthetics based on two factors namely gingival display and alignment of teeth. Materials and Methods: A total of 32 females were randomly selected among dental students in the International Campus of School of Dentistry, Tehran University of Medical Sciences (Tehran, Iran) with no previous history of esthetic dental work. Frontal photographs were obtained and cropped from the subnasal to menton areas of subjects to standardize the size of pictures. Three series of slides were prepared of the pictures using Microsoft PowerPoint software. The first series of slides were shown to familiarize the observers with the images. The second and third series were displayed for the observers and they were then asked to fill out a questionnaire. The group of observers included 10 dental specialists and 10 laypersons. Each observer was given a visual analog scale (VAS) chart for scoring (1–10). After completion of the questionnaires, data were transferred to a computer and the differences in judgments of professionals and laypeople were analyzed using the Mann Whitney test. Results: No significant difference was found in the judgments of professionals and laypeople on evaluating overall smile esthetics, gingival display and alignment of teeth except for the slide showing a reverse smile arc. Conclusions: Laypeople and professionals had similar perceptions of smile esthetics. Thus, it appears that clinicians can rely on the judgment of laypersons in esthetic dental treatments. PMID:27928236

  20. Fracture resistance of 3 types of primary esthetic stainless steel crowns.

    Science.gov (United States)

    Beattie, Sean; Taskonak, Burak; Jones, James; Chin, Judith; Sanders, Brian; Tomlin, Angela; Weddell, James

    2011-01-01

    Demand is increasing for esthetic restorations in pediatric dentistry. When full coverage is indicated, one option is to use esthetic stainless steel crowns (SSCs). However, this type of crown is prone to fracture. The purpose of this study was to evaluate the fracture resistance of 3 types of esthetic SSCs. Esthetic SSCs for first primary mandibular molars were cemented to idealized epoxy dies with glass ionomer cement. The die-crown units were fractured on a universal testing machine. The force was delivered by a stainless steel ball fixture, set in a uniaxial lever to replicate a cusp contact, with a crosshead speed of 1 mm/min. The differences among the 3 types of crown, in terms of force required to fracture, were compared statistically by 1-way analysis of variance. Pairwise comparisons were performed with Fisher's protected least significant difference test, at an overall significance level of 5%. The force required to fracture, expressed as average ± standard error, did not differ significantly among the 3 brands of esthetic SSCs: 1730 N ± 50 N, 1826 N ± 62 N and 1671 N ± 68 N, respectively (p = 0.19), well below the maximum bite force of pediatric patients determined in a previous study. Esthetic SSCs should be able to resist occlusal forces over short clinical periods. However, long-term occlusal loading and fatigue failures should be taken into account when evaluating the success of this type of crown.

  1. The Smile Esthetic Index (SEI): A method to measure the esthetics of the smile. An intra-rater and inter-rater agreement study.

    Science.gov (United States)

    Rotundo, Roberto; Nieri, Michele; Bonaccini, Daniele; Mori, Massimiliano; Lamberti, Elena; Massironi, Domenico; Giachetti, Luca; Franchi, Lorenzo; Venezia, Piero; Cavalcanti, Raffaele; Bondi, Elena; Farneti, Mauro; Pinchi, Vilma; Buti, Jacopo

    2015-01-01

    To propose a method to measure the esthetics of the smile and to report its validation by means of an intra-rater and inter-rater agreement analysis. Ten variables were chosen as determinants for the esthetics of a smile: smile line and facial midline, tooth alignment, tooth deformity, tooth dischromy, gingival dischromy, gingival recession, gingival excess, gingival scars and diastema/missing papillae. One examiner consecutively selected seventy smile pictures, which were in the frontal view. Ten examiners, with different levels of clinical experience and specialties, applied the proposed assessment method twice on the selected pictures, independently and blindly. Intraclass correlation coefficient (ICC) and Fleiss' kappa) statistics were performed to analyse the intra-rater and inter-rater agreement. Considering the cumulative assessment of the Smile Esthetic Index (SEI), the ICC value for the inter-rater agreement of the 10 examiners was 0.62 (95% CI: 0.51 to 0.72), representing a substantial agreement. Intra-rater agreement ranged from 0.86 to 0.99. Inter-rater agreement (Fleiss' kappa statistics) calculated for each variable ranged from 0.17 to 0.75. The SEI was a reproducible method, to assess the esthetic component of the smile, useful for the diagnostic phase and for setting appropriate treatment plans.

  2. Zirconium for esthetic rehabilitation: An overview

    Directory of Open Access Journals (Sweden)

    Anjana Raut

    2011-01-01

    Full Text Available The demand for esthetic restorations has resulted in an increased use of dental ceramics for anterior and posterior restorations. A few decades ago, all-ceramic restorations were restricted to treatment in the anterior region, but now all-ceramic restorations can be made anywhere in the dentition. The properties of traditional ceramic materials, however, have limited their use to single crowns; larger restorations have been inadvisable because of insufficient strength. In attempts to meet the requirements for dental materials and improve strength and toughness, several new ceramic materials and techniques have been developed during the past few decades The paper reviews the current literature on dental zirconia with respect to survival, properties, marginal fit, cementation, esthetics and suggests clinical recommendations for their use.

  3. Tooth wear and wear investigations in dentistry.

    Science.gov (United States)

    Lee, A; He, L H; Lyons, K; Swain, M V

    2012-03-01

    Tooth wear has been recognised as a major problem in dentistry. Epidemiological studies have reported an increasing prevalence of tooth wear and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Although the dental literature contains numerous publications related to management and rehabilitation of tooth wear of varying aetiologies, our understanding of the aetiology and pathogenesis of tooth wear is still limited. The wear behaviour of dental biomaterials has also been extensively researched to improve our understanding of the underlying mechanisms and for the development of restorative materials with good wear resistance. The complex nature of tooth wear indicates challenges for conducting in vitro and in vivo wear investigations and a clear correlation between in vitro and in vivo data has not been established. The objective was to critically review the peer reviewed English-language literature pertaining to prevalence and aetiology of tooth wear and wear investigations in dentistry identified through a Medline search engine combined with hand-searching of the relevant literature, covering the period between 1960 and 2011. © 2011 Blackwell Publishing Ltd.

  4. Application of radionuclide techniques to study the wear behaviour of peripherally treated and coated components

    International Nuclear Information System (INIS)

    Hirsch, E.; Mayer, K.H.; Rodrian, U.; Scheidemantel, N.; Schweizer, R.

    1990-07-01

    Technically and economically important machinery components (helical gear wheels, camshafts, rams, valve rockers) were to be optimized with regard to their wear behaviour under operation-oriented load conditions, and the process parameters required both for peripheral layer heating and surface coating were to be determined. Based on earlier experiments, the treatment parameters and the basic materials were varied. The layer structure was studied, characterized and correlated wi the wear behaviour. The wearing parts were activated in the reactor by thermal neutrons, or in the cyclotron by charged particles. By labelling various parts by means of different radioisotopes, up to three components may be measured at the same time in practice, provided that the circumstances are favourable. (BBR) [de

  5. Evaluation of different esthetic smile criteria.

    Science.gov (United States)

    Al-Johany, Sulieman S; Alqahtani, Abdulaziz S; Alqahtani, Fahd Y; Alzahrani, Adel H

    2011-01-01

    The aim of this study was to evaluate the existence of different esthetic smile criteria as determined on the smiles of celebrities, which were considered by lay people to be beautiful. An Internet search for "best smile" and "female celebrities" in the years 2007 and 2008 identified 50 celebrities who were voted to have beautiful smiles. Another search was made for images of these celebrities that showed the entire face with an open smile. The images were analyzed using Digimizer image analysis software for different esthetic smile criteria. Eighty percent of the sample was classified as having an average upper lip position, 62% showed upward upper lip curvature, and 78% had a parallel smile line. Forty-two percent of the images showed the maxillary anterior teeth not touching the lower lip, while 34% were touching, and 24% slightly covered it. Sixty percent displayed up to the second premolar, and 32% displayed up to the first molar when smiling. Midline deviation was detected in 36% of the sample. Diastema and golden proportion were not seen in any of the subjects. Female celebrities voted to have the best smile by lay people showed most of the esthetic smile criteria with slight variations, except for the golden proportion. The opinions and perceptions of lay people about beauty should be studied and evaluated.

  6. Simplified management of anterior worn dentition

    Directory of Open Access Journals (Sweden)

    Haroon Rashid

    2013-01-01

    Full Text Available Tooth wear has started to affect a greater number of younger people. Its precautions, symptoms, and treatment modalities therefore have to be well understood. This case study presents a patient with severe tooth wear that had led to displeasing esthetics. Surgical crown lengthening and composite restorations were performed after the provision of a stabilizing splint. This helped to improve the esthetics considerably leaving the patient satisfied. The aim of this case study is to portray an approach to how even a patient with severe tooth wear can have access to an esthetically pleasing dentition.

  7. Esthetic correction in open bite

    Directory of Open Access Journals (Sweden)

    Swapnil Parlani

    2011-01-01

    Full Text Available Deleterious oral habits, which are persistent, can lead to poor esthetics of a beautiful face. Conventional treatment modalities for an open bite usually include orthodontic treatment and/or skeletal surgery. This article focuses on a different treatment modality for an anterior open bite.

  8. Study of Tool Wear Mechanisms and Mathematical Modeling of Flank Wear During Machining of Ti Alloy (Ti6Al4V)

    Science.gov (United States)

    Chetan; Narasimhulu, A.; Ghosh, S.; Rao, P. V.

    2015-07-01

    Machinability of titanium is poor due to its low thermal conductivity and high chemical affinity. Lower thermal conductivity of titanium alloy is undesirable on the part of cutting tool causing extensive tool wear. The main task of this work is to predict the various wear mechanisms involved during machining of Ti alloy (Ti6Al4V) and to formulate an analytical mathematical tool wear model for the same. It has been found from various experiments that adhesive and diffusion wear are the dominating wear during machining of Ti alloy with PVD coated tungsten carbide tool. It is also clear from the experiments that the tool wear increases with the increase in cutting parameters like speed, feed and depth of cut. The wear model was validated by carrying out dry machining of Ti alloy at suitable cutting conditions. It has been found that the wear model is able to predict the flank wear suitably under gentle cutting conditions.

  9. The Belt voice: Acoustical measurements and esthetic correlates

    Science.gov (United States)

    Bounous, Barry Urban

    This dissertation explores the esthetic attributes of the Belt voice through spectral acoustical analysis. The process of understanding the nature and safe practice of Belt is just beginning, whereas the understanding of classical singing is well established. The unique nature of the Belt sound provides difficulties for voice teachers attempting to evaluate the quality and appropriateness of a particular sound or performance. This study attempts to provide answers to the question "does Belt conform to a set of measurable esthetic standards?" In answering this question, this paper expands on a previous study of the esthetic attributes of the classical baritone voice (see "Vocal Beauty", NATS Journal 51,1) which also drew some tentative conclusions about the Belt voice but which had an inadequate sample pool of subjects from which to draw. Further, this study demonstrates that it is possible to scientifically investigate the realm of musical esthetics in the singing voice. It is possible to go beyond the "a trained voice compared to an untrained voice" paradigm when evaluating quantitative vocal parameters and actually investigate what truly beautiful voices do. There are functions of sound energy (measured in dB) transference which may affect the nervous system in predictable ways and which can be measured and associated with esthetics. This study does not show consistency in measurements for absolute beauty (taste) even among belt teachers and researchers but does show some markers with varying degrees of importance which may point to a difference between our cognitive learned response to singing and our emotional, more visceral response to sounds. The markers which are significant in determining vocal beauty are: (1) Vibrancy-Characteristics of vibrato including speed, width, and consistency (low variability). (2) Spectral makeup-Ratio of partial strength above the fundamental to the fundamental. (3) Activity of the voice-The quantity of energy being produced. (4

  10. Enhancement of Engine Oil Wear and Friction Control Performance Through Titanium Additive Chemistry

    International Nuclear Information System (INIS)

    Guevremont, J.; Guinther, G.; Szemenyei, D.; Devlin, M.; Jao, T.; Jaye, C.; Woicik, J.; Fischer, D.

    2008-01-01

    Traditionally, wear protection and friction modification by engine oil is provided by zinc dithiophosphate (ZDDP) or other phosphorus compounds. These additives provide effective wear protection and friction control on engine parts through formation of a glassy polyphosphate antiwear film. However, the deposition of phosphorus species on automotive catalytic converters from lubricants has been known for some time to have a detrimental effect of poisoning the catalysts. To mitigate the situation, the industry has been making every effort to find ZDDP-replacement additives that are friendly to catalysts. Toward this goal we have investigated a titanium additive chemistry as a ZDDP replacement. Fully formulated engine oils incorporating this additive component have been found to be effective in reducing wear and controlling friction in a high-frequency reciprocating rig (HFRR), 4-ball bench wear, Sequence IIIG, and Sequence IVA engine tests. Surface analysis of the tested parts by Auger electron spectroscopy, secondary ion mass spectrometry (SIMS), and X-ray photoelectron spectroscopy (XPS) have shown that Ti species have been incorporated into the wear tracks and can only be found on the wear tracks. We used synchrotron based near edge X-ray absorption fine structure (NEXAFS) to investigate the chemical bonding mechanism of the Ti additive with the metal surface that affects the wear improvement mechanism. We postulate that Ti provides antiwear enhancement through inclusion in the metal/metal oxide structure of the ferrous surface by forming FeTiO3.

  11. Esthetic Outcomes of Immediately Loaded Locking Taper Implants in the Anterior Maxilla: A Case Series Study.

    Science.gov (United States)

    Lombardo, Giorgio; Corrocher, Giovanni; Pighi, Jacopo; Mascellaro, Anna; Marincola, Mauro; Nocini, Per Francesco

    2016-06-01

    The purpose of this study was to evaluate the esthetic outcome of single-tooth locking taper connection implants placed in the anterior maxilla following a postextractive nonfunctional loading protocol. This preliminary clinical study involving 16 patients evaluated the results of 21 implants placed in areas with high esthetic value. For each implant the pink esthetic score, white esthetic score, cumulative survival rate, and health status of peri-implant tissues were evaluated. The cumulative survival rate was 100% 2 years after prosthetic loading, and the mean total pink esthetic score/white esthetic score was 16.9 ± 1.14 on a maximum value of 20. There was excellent plaque control in all patients, and inflammation indices were within the norm. Within the limits of this study, this immediate nonfunctional loading protocol seems to be a successful procedure esthetically and for the maintenance of peri-implant soft tissues.

  12. Wear of PEEK-OPTIMA® and PEEK-OPTIMA®-Wear Performance articulating against highly cross-linked polyethylene.

    Science.gov (United States)

    East, Rebecca H; Briscoe, Adam; Unsworth, Anthony

    2015-03-01

    The idea of all polymer artificial joints, particularly for the knee and finger, has been raised several times in the past 20 years. This is partly because of weight but also to reduce stress shielding in the bone when stiffer materials such as metals or ceramics are used. With this in mind, pin-on-plate studies of various polyetheretherketone preparations against highly cross-linked polyethylene were conducted to investigate the possibility of using such a combination in the design of a new generation of artificial joints. PEEK-OPTIMA(®) (no fibre) against highly cross-linked polyethylene gave very low wear factors of 0.0384 × 10(-6) mm(3)/N m for the polyetheretherketone pins and -0.025 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates. The carbon-fibre-reinforced polyetheretherketone (PEEK-OPTIMA(®)-Wear Performance) also produced very low wear rates in the polyetheretherketone pins but produced very high wear in the highly cross-linked polyethylene, as might have been predicted since the carbon fibres are quite abrasive. When the fibres were predominantly tangential to the sliding plane, the mean wear factor was 0.052 × 10(-6) mm(3)/N m for the pins and 49.3 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates; a half of that when the fibres ran axially in the pins (0.138 × 10(-6) mm(3)/N m for the pins and 97.5 × 10(-6) mm/ N m for the cross-linked polyethylene plates). PEEK-OPTIMA(®) against highly cross-linked polyethylene merits further investigation. © IMechE 2015.

  13. Destructive investigations of decommissioned guide tubes: characterization of wear

    International Nuclear Information System (INIS)

    Ambard, A.; Lina, A.; Bosselut, D.; Deforge, D.; Robinot, P.; Thebault, Y.; Paulhies, M.; Maingot, S.

    2011-01-01

    The wear of control rods has been a major maintenance concern for EDF since the nineties. Surface treatment of the rods (nitriding, chrome plating) were developed to deal with this issue. However, the question came to know whether the guiding tube in which those new control rods are inserted are also worn. EDF interest into guide tube wear has been renewed by the slow increase of the drop time in B06 position. EDF performed field examinations and some laboratory experiments to answer to this question. Two guide tubes were extracted from various cores. They were chosen due to their different positions within the core and the different nature of their counter bodies (different control rods surface treatment). Their continuous part were sliced to reduce their activity. Their dimensions were measured and compared to the nominal dimensions. Wear was evidenced with a low level. It is mainly concentrated around the notch. Some distinctions could be made depending on the guiding tube examined. Metallographic examinations were performed using SEM. The wear patterns of the guiding tubes appear similar from those of the control rods, which means that similar wear mechanisms must be involved. A tentative explanation of the increase of the rod drop time in position B06 is proposed. A tentative explanation of the low increase of rod drop time is presented. It could result from the conjunction of a larger pressing force in B06 position than in other position of the core as well as the conformal contact observed. The conformal contact in itself could results from the larger pressing force and the use of hardened rods. The findings of these field examinations have comforted EDF strategy concerning B06 guide tubes: they are changed before their drop time reaches a critical value. (authors)

  14. Evaluation of the influence exerted by different dental specialty backgrounds and measuring instrument reproducibility on esthetic aspects of maxillary implant-supported single crown.

    Science.gov (United States)

    Vaidya, Samriddhi; Ho, Yu Lau Elaine; Hao, Jie; Lang, Niklaus P; Mattheos, Nikos

    2015-03-01

    To evaluate the influence exerted by different dental specialty backgrounds as well as the validity and reproducibility of the Pink Esthetic Score/White Esthetic Score (PES/WES) and the modified Implant Crown Aesthetic Index (mod-ICAI) on the assessment of esthetic aspects of maxillary implants supported single-tooth prosthesis. A total of fourteen examiners (Two orthodontists, two prosthodontists, two oral surgeons, two periodontists, two dental technicians, two dental assistants, and two postgraduate students in Implant Dentistry evaluated 20 photographs of single-implant-supported crowns and five photographs of unrestored teeth of esthetic zone in a two part study. The examiners assessed the photographs with each index (Pink Esthetic Score/White Esthetic Score and modified Implant Crown Aesthetic Index), twice with a week's interval. Orders of photographs were rearranged in the second assessment. Kruskal-Wallis test results showed significant differences among all the six specialties (P ≤ 0.001). DAs and periodontists had significantly better ratings than other specialties with both indices. Prosthodontists had the lowest mean rank scores regardless of the index. Interobserver agreement was also lowest between the two prosthodontists (4-28%), rest of the groups had low-to-moderate agreement (20-80%) when limited allowance was accepted. With mod-ICAI, more interobserver agreement was noted within the specialty group than with PES/WES. The PES/WES and the modified ICAI can be reliable estimates of esthetic outcomes. The assessor degree of specialization affected the esthetic evaluation with both the PES/WES and the modified ICAI. DAs and periodontists were identified to provide more favorable ratings than other specialties while prosthodontists were most critical in this study. With modified ICAI, more interobserver agreement within specialty resulted. The interexaminer agreement may be increased if more tolerance of 1-2 points is considered. © 2014 John Wiley

  15. Putative golden proportions as predictors of facial esthetics in adolescents.

    Science.gov (United States)

    Kiekens, Rosemie M A; Kuijpers-Jagtman, Anne Marie; van 't Hof, Martin A; van 't Hof, Bep E; Maltha, Jaap C

    2008-10-01

    In orthodontics, facial esthetics is assumed to be related to golden proportions apparent in the ideal human face. The aim of the study was to analyze the putative relationship between facial esthetics and golden proportions in white adolescents. Seventy-six adult laypeople evaluated sets of photographs of 64 adolescents on a visual analog scale (VAS) from 0 to 100. The facial esthetic value of each subject was calculated as a mean VAS score. Three observers recorded the position of 13 facial landmarks included in 19 putative golden proportions, based on the golden proportions as defined by Ricketts. The proportions and each proportion's deviation from the golden target (1.618) were calculated. This deviation was then related to the VAS scores. Only 4 of the 19 proportions had a significant negative correlation with the VAS scores, indicating that beautiful faces showed less deviation from the golden standard than less beautiful faces. Together, these variables explained only 16% of the variance. Few golden proportions have a significant relationship with facial esthetics in adolescents. The explained variance of these variables is too small to be of clinical importance.

  16. Ethics and marketing in esthetic dentistry

    Directory of Open Access Journals (Sweden)

    Obradović-Đuričić Kosovka

    2017-01-01

    Full Text Available Contemporary dentistry is, first of all, characterized by diverse accelerated development, owing to improvements of information and other technologies, as well as the development of dental materials (shape-memory biomaterials, nanomaterials, biomaterials for application in tissue engineering, etc.. Expert doctrinaire attitudes move from the direction of operative interventions, whereby disease and acute symptoms are primarily treated, towards the strengthening of oral health by minimally invasive procedures. A particular place in patients’ total rehabilitation belongs to numerous esthetic procedures which, to a large extent, make up a wants-based service, led by the patients’ needs and affinities. This paper deals with differences between cosmetic and esthetic dentistry. The complexity of esthetic dentistry, which favors therapy with the change of function parameters in care for the patient, is emphasized. On the other hand, more attention is paid to the need to know and respect ethical and marketing principles that follow any activity of dentists, starting from the first contact with the patient, the selection of certified materials, to the implementation of the appropriate treatment plan. Well-directed communication and comprehensive awareness of the patient, the use of the visual analog scale, consideration of realistic resources in therapy, and the acceptance of de Bono model of adopted parallel thinking are determinants which help dentists define a problem adequately, find quality solutions, open alternative solutions, and reduce the potential risks in patients’ therapy.

  17. Esthetic outcome and alterations of soft tissue around single implant crowns: a 2-year prospective study.

    Science.gov (United States)

    Gu, Ying-Xin; Shi, Jun-Yu; Zhuang, Long-Fei; Qiao, Shi-Chong; Xu, You-You; Lai, Hong-Chang

    2015-08-01

    The aim of this prospective study was to assess the esthetic outcome and alterations of peri-implant soft tissue using tissue-level implants. Furthermore, the influencing factors, including grafting and gingival biotype, of esthetic outcome of peri-implant soft tissue were also evaluated. Of 38 patients with single missing anterior tooth in maxilla were treated with a Straumann (®) Standard Plus SLA implant. Bone augmentation was performed in 24 patients. Follow-up was conducted at 12 and 24 months after definitive crowns placement. Esthetic outcome using the pink esthetic score/white esthetic score (PES/WES) and clinical parameters were evaluated. The mean PES/WES value at baseline, 1-year, and 2-year examination was 13.79, 14.87, and 14.96. Significant improvement was found between baseline and 1-year examination (P esthetic area. Favorable short-term esthetic outcome and stability of soft tissue around single implant crowns can be expected in patients with or without graft. However, graft procedures might have an unfavorable effect on the esthetic outcome. Gingival biotype can be considered as prognostic factor for esthetic outcome. RCTs with long-term follow-up are needed to provide evidence for the long-term stability of peri-implant soft tissue using tissue-level implant systems. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Overcoming esthetic challenges in the smile zone using the "roll flap procedure"

    Directory of Open Access Journals (Sweden)

    Rahul G Wagle

    2010-01-01

    Full Text Available Hard and soft tissue alveolar ridge deformities occur following the extraction of teeth, creating functional and esthetic tooth replacement challenges, especially in the esthetic zone. A surgical technique using a roll flap technique for ridge augmentation is discussed which when combined with conventional fixed partial dentures for tooth replacement creates a template of the labial and interproximal sulcus at the edentulous site, allowing for the molding of an ovate pontic resulting in greatly improved esthetics in an esthetically compromised case. This results in vastly improved restorative emergence profiles with minimal or no change in the height of the labial gingival margin and the form and height of the interproximal papillae with adjacent teeth. This technique enhances soft tissue contours adjacent to the definitive restoration that vary little from those of the original natural tooth.

  19. An Island of Stability: Art Images and Natural Scenes - but Not Natural Faces - Show Consistent Esthetic Response in Alzheimer's-Related Dementia.

    Science.gov (United States)

    Graham, Daniel J; Stockinger, Simone; Leder, Helmut

    2013-01-01

    Alzheimer's disease (AD) causes severe impairments in cognitive function but there is evidence that aspects of esthetic perception are somewhat spared, at least in early stages of the disease. People with early Alzheimer's-related dementia have been found to show similar degrees of stability over time in esthetic judgment of paintings compared to controls, despite poor explicit memory for the images. Here we expand on this line of inquiry to investigate the types of perceptual judgments involved, and to test whether people in later stages of the disease also show evidence of preserved esthetic judgment. Our results confirm that, compared to healthy controls, there is similar esthetic stability in early stage AD in the absence of explicit memory, and we report here that people with later stages of the disease also show similar stability compared to controls. However, while we find that stability for portrait paintings, landscape paintings, and landscape photographs is not different compared to control group performance, stability for face photographs - which were matched for identity with the portrait paintings - was significantly impaired in the AD group. We suggest that partially spared face-processing systems interfere with esthetic processing of natural faces in ways that are not found for artistic images and landscape photographs. Thus, our work provides a novel form of evidence regarding face-processing in healthy and diseased aging. Our work also gives insights into general theories of esthetics, since people with AD are not encumbered by many of the semantic and emotional factors that otherwise color esthetic judgment. We conclude that, for people with AD, basic esthetic judgment of artistic images represents an "island of stability" in a condition that in most other respects causes profound cognitive disruption. As such, esthetic response could be a promising route to future therapies.

  20. Orofacial esthetics and dental anxiety: associations with oral and psychological health.

    Science.gov (United States)

    Carlsson, Viktor; Hakeberg, Magnus; Blomkvist, Klas; Wide Boman, Ulla

    2014-11-01

    Severe dental anxiety (DA) is associated with both oral health and psychosocial consequences in what has been described as a vicious circle of DA. The aim of this study was to investigate self-rated orofacial esthetics in patients with DA and its relationship to psychological and oral health. A consecutive sample of 152 adult patients who were referred or self-referred to a specialized dental anxiety clinic filled out the Orofacial Esthetic Scale (OES) as well as measurements on DA, self-rated oral health and general anxiety and depression. Clinical measures of dental status were also obtained. Compared with the general population, patients with DA had lower ratings of satisfaction on all aspects of their orofacial esthetics, which included the teeth, gingiva, mouth and face, as well as a global orofacial assessment. Furthermore, the perception of the orofacial appearance was related both to dental status and self-rated oral health, as well as to general anxiety and depression. The level of dissatisfaction with the orofacial appearance was similar for both genders, but women reported more regular dental care and better dental status. The results of this study clearly show less satisfaction with dental and facial appearance in patients with DA, and that the self-rating of orofacial esthetics is related to both oral and psychological health. The OES can be used to assess orofacial esthetics in patients with DA.

  1. Craniodentofacial characteristics, dental esthetics-related quality of life, and self-esteem.

    Science.gov (United States)

    Gavric, Anja; Mirceta, Dubravka; Jakobovic, Mario; Pavlic, Andrej; Zrinski, Magda Trinajstic; Spalj, Stjepan

    2015-06-01

    Self-esteem is a psychological trait that may develop in interaction with craniodentofacial esthetics. The aim of this study was to explore the relationship among craniodentofacial characteristics, dental esthetics-related quality of life, and self-esteem in adolescents and young adults. The study was cross-sectional; the sample included 200 pupils and university students (58% female) aged 13 to 33 years. The Rosenberg Self-Esteem Scale and the Psychosocial Impact of Dental Aesthetics Questionnaire were used. Craniodentofacial features were estimated by the method of Martin and Saller, the Index of Orthodontic Treatment Need, and the Index of Complexity, Outcome and Need. When malocclusion severity increases, dental esthetics-related quality of life decreases. The multiple linear regression showed that with the control of all other predictors in the model, the social impact of dental esthetics, borderline dental self-confidence, and facial type contribute the most to explain the variability of self-esteem, accounting for 3.2%, 1.3%, and 1.4%, respectively, of the variability values. The whole model accounts for 24.2% of the variability of self-esteem. In adolescents and young adults, self-esteem appears to be more influenced by the self-perceived psychosocial impacts of dental esthetics than the normative level of malocclusion, craniofacial typology, sex, or age. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  2. Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

    Science.gov (United States)

    Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

    2018-04-01

    Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (edge-loading conditions generated particles that ranged from Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 986-996, 2018. © 2017 Wiley Periodicals, Inc.

  3. Opalescence of human teeth and dental esthetic restorative materials.

    Science.gov (United States)

    Lee, Yong-Keun

    2016-12-01

    Human tooth enamel is opalescent, which renders teeth bluish in reflected and orange in transmitted color. The aim was to review opalescent property of teeth and application and mimetic reproduction in esthetic restorations. A PubMed search for articles published in English till 2015 on the opalescence of teeth and esthetic materials revealed 29 relevant papers. Opalescence was measured with OP-RT index, which was calculated as the difference in the yellow-blue and red-green color coordinates between the reflected and transmitted colors. Mean OP-RT value of human enamel was 22.9. OP-RT values of direct resin composites changed after polymerization, and the range in these materials was 5.7-23.7. OP-RT value ranges were 1.6-6.1 and 2.0-7.1 for the core and veneer ceramics, respectively. Since the OP-RT values of esthetic materials were lower than that of enamel, it is recommended that materials that can reproduce the opalescence of enamel be further designed.

  4. Esthetic periodontal surgery for impacted dilacerated maxillary central incisors.

    Science.gov (United States)

    Wei, Yu-Ju; Lin, Yi-Chun; Kaung, Shou-Shin; Yang, Shue-Fen; Lee, Shyh-Yuan; Lai, Yu-Lin

    2012-10-01

    Clinicians do not frequently see impacted dilacerated maxillary incisors in their patients. When they do, there are several diagnostic and management challenges for correcting root dilacerations. An unfavorable esthetic outcome might occur as a result of soft-tissue complications during surgical eruption procedures. We present 2 patients with an impacted and dilacerated maxillary central incisor. Computed tomography scans with 3-dimensional reformation were used to accurately assess the positions of the dilacerated teeth, the degree of dilaceration, and the stage of root formation. The therapy primarily involved 2-stage crown exposure surgery combined with orthodontic traction. An apicoectomy was performed on 1 dilacerated tooth; the other exhibited pulp vitality. This article highlights the periodontal surgical strategies for the esthetic management of inverted crowns. Through periodontal plastic surgery and interdisciplinary cooperation, the impacted dilacerated central incisors were properly aligned, and successful esthetic results were achieved. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  5. Long-term Stability of Soft Tissue Esthetic Outcomes Following Conventional Single Implant Treatment in the Anterior Maxilla: 10-12 Year Results.

    Science.gov (United States)

    Rokn, A; Bassir, S H; Rasouli Ghahroudi, A A; Kharazifard, M J; Manesheof, R

    2016-01-01

    The present study aimed to evaluate the long-term stability of esthetic outcomes of soft tissue around maxillary anterior single-tooth implants after 10-to-12 years of loading. Patients who had been treated for single-tooth implants in the anterior maxilla between February 2000 and July 2002 were invited to participate in the study. All implants had been placed according to delayed implant placement and conventional loading protocols without any connective tissue graft or papilla preservation flaps. Pink Esthetic Score (PES) was rated using standardized clinical photographs to assess the esthetic outcomes of the implant treatment at the time of crown placement and at time of follow-up examination which was at least 10 years after the crown placement. A total of 19 patients were included. The mean score of PES was 11.63 (SD 1.61; range 7-14) at baseline. After 10-to-12 years of function, a mean PES score of 11.05 (SD 2.09; range 6-14) was recorded. No significant differences were found in the esthetic outcomes, categorized based on clinically relevant levels, between the baseline and follow-up session (p>0.05). Within limitation of the present study, it can be concluded that the esthetic outcomes of soft tissue around the maxillary anterior single-tooth implants placed using conventional implant placement technique remained stable in the long-term.

  6. Testing the Logistics Model of Supplying Military Vehicles with Spare Parts

    Directory of Open Access Journals (Sweden)

    Robert Spudić

    2007-07-01

    Full Text Available The use of advanced transport means understands alsotheir supply by spare and consumable parts. In order to solvethe problem of the required quantities, costs of purchase andstorage of the parts, it is necessary to solve the problem of stocksmanagement. The wear of tyres for military vehicles in extremeexploitation conditions is of random character. How fast thetyres will wear on the all-ten·ain and heavy motor vehicle dependson the driver's skill and the external conditions (weather,terrain. All the conditions are of random character and in orderto determine as accurately as possible the wear of tyres it isnecessary to monitor the wear of tyres within a certain time period,and to find the approximate probability of tyre wear in thefuture period of time. When the probability of tyre wear is determined,stochastic supply management model is used to calculatethe value of the stocks which allows optimal planning ofstocks of spare parts at minimal costs. The stochastic model allowsoptimal calculation for the purchase of consumable partsof transport means whose consumption depends on the randomconditions and events.

  7. Comparison of two measurement techniques for clinical wear

    DEFF Research Database (Denmark)

    Peters, M C; Delong, R; Pintado, M R

    1999-01-01

    Clinical wear of restorations is generally evaluated by marginal integrity over time. In this study, both a subjective and an objective method for wear assessment are compared, and the relative advantages and disadvantages of each are considered.......Clinical wear of restorations is generally evaluated by marginal integrity over time. In this study, both a subjective and an objective method for wear assessment are compared, and the relative advantages and disadvantages of each are considered....

  8. Evaluation of mechanical properties of esthetic brackets.

    Science.gov (United States)

    Matsui, Shigeyuki; Umezaki, Eisaku; Komazawa, Daigo; Otsuka, Yuichiro; Suda, Naoto

    2015-01-01

    Plastic brackets, as well as ceramic brackets, are used in various cases since they have excellent esthetics. However, their mechanical properties remain uncertain. The purpose of this study was to determine how deformation and stress distribution in esthetic brackets differ among materials under the same wire load. Using the digital image correlation method, we discovered the following: (1) the strain of the wings of plastic brackets is within 0.2% and that of ceramic and metal brackets is negligible, (2) polycarbonate brackets having a stainless steel slot show significantly smaller displacement than other plastic brackets, and (3) there is a significant difference between plastic brackets and ceramic and stainless steel brackets in terms of the displacement of the bracket wing.

  9. The friction wear of electrolytic composite coatings

    International Nuclear Information System (INIS)

    Starosta, R.

    2002-01-01

    The article presents the results of investigation of wear of galvanic composite coatings Ni-Al 2 O 3 and Ni-41%Fe-Al 2 O 3 . The diameter of small parts of aluminium oxide received 0.5; 3; 5 μm. Investigations of friction sliding were effected on PT3 device at Technical University of Gdansk. Counter sample constituted a funnel made of steel NC6 (750 HV). Increase of wear coatings together with the rise of iron content in matrix is observed. The rise of sizes of ceramic particles caused decrease of wear of composite coatings, but rise of steel funnel wear. The friction coefficient increased after ceramic particle s were built in coatings. The best wear resistance characterized Ni-41%Fe-Al 2 O 3 coatings containing 2.2x10 6 mm -2 ceramic particles. (author)

  10. Wear, creep, and frictional heating of femoral implant articulating surfaces and the effect on long-term performance--Part II, Friction, heating, and torque.

    Science.gov (United States)

    Davidson, J A; Schwartz, G; Lynch, G; Gir, S

    1988-04-01

    In Part I, (J.A. Davidson and G. Schwartz, "Wear, creep, and frictional heating of femoral implant articulating surfaces and the effect on long-term performance--Part I, A review," J. Biomed. Mater. Res., 21, 000-000 (1987) it was shown that lubrication of the artificial hip joint was complex and that long-term performance is governed by the combined wear, creep, and to a lesser extent, oxidation degradation of the articulating materials. Importantly, it was shown that a tendency for heating exists during articulation in the hip joint and that elevated temperatures can increase the wear, creep, and oxidation degradation rate of UHMWPE. The present study was performed to examine closely the propensity to generate heat during articulation in a hip joint simulator. The systems investigated were polished Co-Cr-Mo alloy articulating against UHMWPE, polished alumina ceramic against UHMWPE, and polished alumina against itself. Frictional torque was also evaluated for each system at various levels of applied loads. A walking load history was used in both the frictional heating and torque tests. The majority of tests were performed with 5 mL of water lubricant. However, the effect of various concentrations of hyaluronic acid was also evaluated. Results showed frictional heating to occur in all three systems, reaching an equilibrium after roughly 30 min articulation time. Ceramic systems showed reduced levels of heating compared to the cobalt alloy-UHMWPE system. The level of frictional torque for each system ranked similar to their respective tendencies to generate heat. Hyaluronic acid had little effect, while dry conditions and the presence of small quantities of bone cement powder in water lubricant significantly increased frictional torque.

  11. Environmental Forces - Some Esthetic Components.

    Science.gov (United States)

    Severino, D. Alexander

    Although our system of mass culture has raised our civilization to an extremely high level of material success and affluence, the fact remains that this system has the inherent flaw of not fully recognizing the esthetic needs of man. To overcome this weakness we need to re-introduce into the system a sizable component of first-hand experience…

  12. Specificity of Esthetic Experience for Artworks: An fMRI Study

    Science.gov (United States)

    Di Dio, Cinzia; Canessa, Nicola; Cappa, Stefano F.; Rizzolatti, Giacomo

    2011-01-01

    In a previous functional magnetic resonance imaging (fMRI) study, where we investigated the neural correlates of esthetic experience, we found that observing canonical sculptures, relative to sculptures whose proportions had been modified, produced the activation of a network that included the lateral occipital gyrus, precuneus, prefrontal areas, and, most interestingly, the right anterior insula. We interpreted this latter activation as the neural signature underpinning hedonic response during esthetic experience. With the aim of exploring whether this specific hedonic response is also present during the observation of non-art biological stimuli, in the present fMRI study we compared the activations associated with viewing masterpieces of classical sculpture with those produced by the observation of pictures of young athletes. The two stimulus-categories were matched on various factors, including body postures, proportion, and expressed dynamism. The stimuli were presented in two conditions: observation and esthetic judgment. The two stimulus-categories produced a rather similar global activation pattern. Direct comparisons between sculpture and real-body images revealed, however, relevant differences, among which the activation of right antero-dorsal insula during sculptures viewing only. Along with our previous data, this finding suggests that the hedonic state associated with activation of right dorsal anterior insula underpins esthetic experience for artworks. PMID:22121344

  13. Effects of Load and Speed on Wear Rate of Abrasive Wear for 2014 Al Alloy

    Science.gov (United States)

    Odabas, D.

    2018-01-01

    In this paper, the effects of the normal load and sliding speed on wear rate of two-body abrasive wear for 2014 Al Alloy were investigated in detail. In order to understand the variation in wear behaviour with load and speed, wear tests were carried out at a sliding distance of 11 m, a speed of 0.36 m/s, a duration of 30 s and loads in the range 3-11 N using 220 grit abrasive paper, and at a speed range 0.09-0.90 m/s, a load of 5 N and an average sliding distance of 11 m using abrasive papers of 150 grit size under dry friction conditions. Before the wear tests, solution treatment of the 2014 Al alloy was carried out at temperatures of 505 and 520 °C for 1 h in a muffle furnace and then quenched in cold water at 15 °C. Later, the ageing treatment was carried out at 185 °C for 8 h in the furnace. Generally, wear rate due to time increased linearly and linear wear resistance decreased with increasing loads. However, the wear rate was directly proportional to the load up to a critical load of 7 N. After this load, the slope of the curves decreased because the excessive deformation of the worn surface and the instability of the abrasive grains began to increase. When the load on an abrasive grain reaches a critical value, the groove width is about 0.17 of the abrasive grain diameter, and the abrasive grains begin to fail. The wear rate due to time increased slightly as the sliding speed increased in the range 0.09-0.90 m/s. The reason for this is that changes arising from strain rate and friction heating are expected with increasing sliding speeds.

  14. Effect of posterior gingival smile on the perception of smile esthetics.

    Science.gov (United States)

    Rodríguez-Martínez, Alicia; Vicente-Hernández, Ascensión; Bravo-González, Luis-Alberto

    2014-01-01

    To evaluate and compare the influence of posterior gummy smile on the perception of smile esthetics by orthodontists, general-dentists and laypersons. A frontal photograph of a smile with normal gum exposure was chosen and manipulated digitally using Adobe Photoshop C3 to generate three further images with posterior gum exposure of 4, 6 and 8mm. These four images were assessed by the three evaluator groups: orthodontists (n=40), general-dentists (n=40) and laypersons (n=40). Both orthodontists and dentists had at least ten years professional experience and laypersons were aged between 40-50 years. The proportion of men to women was 20:20 in each group. Evaluators awarded a score to the smile esthetics of each image: 1=acceptable, 2=moderately acceptable, 3=unacceptable. Afterwards, each evaluator placed the four images in order of esthetic preference. No significant differences (p>0.05) were detected between the three evaluator groups for the photo without posterior gummy smile. The perception of smile esthetics for a the 4mm posterior gummy smile (median for orthodontists=2, general-dentists= 1, laypersons=1), the 6mm (median for orthodontists=2, general-dentists=1, laypersons=1) and the 8mm (median for orthodontists=3, general-dentists=2, laypersons=2) was significantly different between orthodontists and the other two evaluator groups (pesthetic preference. Posterior gummy smile influences the perception of smile esthetics more negatively among orthodontists than the rest of the groups.

  15. Facial profile esthetic preferences: perception in two Brazilian states

    Science.gov (United States)

    de Oliveira, Marina Detoni Vieira; da Silveira, Bruno Lopes; Mattos, Cláudia Trindade; Marquezan, Mariana

    2015-01-01

    OBJECTIVE: The aim of this study was to assess the regional influence on the perception of facial profile esthetics in Rio de Janeiro state (RJ) and Rio Grande do Sul state (RS), Brazil. METHODS: Two Caucasian models, a man and a woman, with balanced facial profiles, had their photographs digitally manipulated so as to produce seven different profiles. First year dental students (laypeople) assessed the images and classified them according to their esthetic preference. RESULTS: The result of the t test for independent samples showed differences among states for certain facial profiles. The female photograph identified with the letter 'G' (mandibular retrusion) received higher scores in RS state (p = 0.006). No differences were found for male photographs (p > 0.007). The evaluators' sex seemed not to influence their esthetic perception (p > 0.007). Considering all evaluators together, ANOVA/Tukey's test showed differences among the profiles (p ≤ 0.05) for both male and female photographs. The female photograph that received the highest score was the one identified with the letter 'F' (dentoalveolar bimaxillary retrusion/ straight profile). For the male profiles, photograph identified with the letter 'E' (dentoalveolar bimaxillary protrusion/ straight profile) received the best score. CONCLUSION: Regional differences were observed regarding preferences of facial profile esthetics. In Rio de Janeiro state, more prominent lips were preferred while in Rio Grande do Sul state, profiles with straight lips were favored. Class III profiles were considered less attractive. PMID:26154461

  16. Does Andrews facial analysis predict esthetic sagittal maxillary position?

    Science.gov (United States)

    Resnick, Cory M; Daniels, Kimberly M; Vlahos, Maryann

    2018-04-01

    Cephalometric analyses have limited utility in planning maxillary sagittal position for orthognathic surgery. In Six Elements of Orofacial Harmony, Andrews quantified maxillary position relative to forehead projection and angulation and proposed an ideal relationship. The purpose of this study was to investigate the ability of this technique to predict esthetic sagittal maxillary position. Survey study including a male and female with straight facial profiles, normal maxillary incisor angulations, and Angle's Class I. Maxillary position was modified on lateral photographs to create 5 images for each participant with incisor-goal anterior limit line (GALL) distances of -4, -2, 0, +2, and +4 mm. A series of health care professionals and laypeople were asked to rate each photo in order of attractiveness. A total of 100 complete responses were received. Incisor-GALL distances of +4 mm (41%) and +2 mm (40%) were most commonly considered "most esthetic" for the female volunteer (P < .001). For the male volunteer, there were 2 peak "most esthetic" responses: incisor-GALL distances of 0 mm (37%) and -4 mm (32%) (P < .001). Respondents considered maxillary incisor position 2 to 4 mm anterior to GALL most attractive in a woman and 0 to 4 mm posterior to GALL most esthetic in a man. Using these modified target distances, this analysis may be useful for orthognathic surgery planning. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Facial profile esthetic preferences: perception in two Brazilian states.

    Science.gov (United States)

    Oliveira, Marina Detoni Vieira de; Silveira, Bruno Lopes da; Mattos, Cláudia Trindade; Marquezan, Mariana

    2015-01-01

    The aim of this study was to assess the regional influence on the perception of facial profile esthetics in Rio de Janeiro state (RJ) and Rio Grande do Sul state (RS), Brazil. Two Caucasian models, a man and a woman, with balanced facial profiles, had their photographs digitally manipulated so as to produce seven different profiles. First year dental students (laypeople) assessed the images and classified them according to their esthetic preference. The result of the t test for independent samples showed differences among states for certain facial profiles. The female photograph identified with the letter 'G' (mandibular retrusion) received higher scores in RS state (p = 0.006). No differences were found for male photographs (p > 0.007). The evaluators' sex seemed not to influence their esthetic perception (p > 0.007). Considering all evaluators together, ANOVA/Tukey's test showed differences among the profiles (p ≤ 0.05) for both male and female photographs. The female photograph that received the highest score was the one identified with the letter 'F' (dentoalveolar bimaxillary retrusion/ straight profile). For the male profiles, photograph identified with the letter 'E' (dentoalveolar bimaxillary protrusion/ straight profile) received the best score. Regional differences were observed regarding preferences of facial profile esthetics. In Rio de Janeiro state, more prominent lips were preferred while in Rio Grande do Sul state, profiles with straight lips were favored. Class III profiles were considered less attractive.

  18. Study on Co-free amorphous material cladding using a laser beam to improve the resistance of primary system parts in NPPs to wear/erosion-corrosion

    International Nuclear Information System (INIS)

    Kim, J. S.; Woo, S. S.; Seo, J. H.

    2001-01-01

    A study on Co-free amorphous material, ARMACOR M, cladding using a laser beam has been performed to improve resistance of the primary system main parts on nuclear power plants to wear/erosion-corrosion. The wear/erosion-corrosion properties of ARMACRO M cladded speciemens were characterized in air at room temperature and 300 .deg. C and in air at room temperature, and compared to those of other hardfacing materials, such as Stellite 6, NOREM 02, Deloro 50, TIG-welde or laer cladded. According to the results, ARMACOR M laser-cladded specimen showed to have the highest resistance to wear/erosion-corrosion

  19. Satisfaction with Dental Appearance and Attitude toward improving Dental Esthetics among Patients attending a Dental Teaching Center.

    Science.gov (United States)

    Maghaireh, Ghada A; Alzraikat, Hanan; Taha, Nessrin A

    2016-01-01

    The aim of this study was to evaluate the factors influencing the satisfaction of dental appearance and attitude toward treatments to improve dental esthetics among patients attending a dental teaching center. A questionnaire was used to collect data of four background variables among 450 patients attended a dental teaching center in the city of Irbid in Jordan. The questionnaire enclosed self-reported questions about the appearance of anterior teeth, received esthetic treatment and desired treatment for improving esthetics. Descriptive, multiple logistic regression and Chi-square tests were used for data analysis (p ≤ 0.05). The 450 participants consisted of (66.2%) male and (33.8%) female. Of these, 69.3% were satisfied with their dental appearance and 58.0% with the color of their teeth. Esthetic restorations were the most received treatment (39.8%) and whitening of teeth was the most desired treatment (55.3%). The patients' satisfaction with dental appearance was influenced by teeth color, crowding and receiving whitening (p < 0.05. r = 0.561, r(2) = 0.315). The most desired esthetic treatments influenced by the satisfaction with dental appearance were esthetic restorations and orthodontics (p < 0.05. r = 0.223, r(2) = 0.05). Significantly more female reported having esthetic restorations and orthodontics (p = 0.008, 0.000) and desired to have orthodontic, crowns or veneers and esthetic restorations (p = 0.000, 0.015, 0.028). Satisfaction with dental appearance was affected by teeth color, feeling teeth are crowded, desire for esthetic restorations and orthodontic treatment. A high percentage of patients were not satisfied with the color of their teeth. Recognizing the factors that affect patients' satisfaction with their present dental appearance and attitude toward treatments to improve dental esthetic can guide clinicians to strategies to improve esthetics.

  20. Dental wear caused by association between bruxism and gastroesophageal reflux disease: a rehabilitation report

    Directory of Open Access Journals (Sweden)

    Naila Aparecida de Godoi Machado

    2007-08-01

    Full Text Available Bruxism is a pathological activity of the stomatognathic system that involves tooth grinding and clenching during parafunctional jaw movements. Clinical signs of bruxism are mostly related to dental wear and muscular and joint discomforts, but a large number of etiological factors can be listed, as local, systemic, psychological and hereditary factors. The association between bruxism, feeding and smoking habits and digestive disorders may lead to serious consequences to dental and related structures, involving dental alterations (wear, fractures and cracks, periodontal signs (gingival recession and tooth mobility and muscle-joint sensivity, demanding a multidisciplinary treatment plan. This paper presents a case report in which bruxism associated with acid feeding, smoking habit and episodes of gastric reflow caused severe tooth wear and great muscular discomfort with daily headache episodes. From the diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow up with counseling on diet and smoking habits and management of the gastric disorders. This was followed by the installation of an interocclusal acrylic device in centric relation of occlusion (CRO for reestablishment of the occlusal stability, vertical dimension of occlusion, anterior guides and return to normal muscle activity (90-day use approximately. After remission of initial symptoms, oral rehabilitation was implemented in CRO by means of full resin composite restorations and new interocclusal device for protection of restorations. Satisfactory esthetics, improved function and occlusal stability were obtained after oral rehabilitation. The patient has attended annual follow-ups for the past 2 years. The multidisciplinary treatment seems to be the key for a successful rehabilitation of severe cases of dental wear involving the association of different health disorders.

  1. Dental wear caused by association between bruxism and gastroesophageal reflux disease: a rehabilitation report.

    Science.gov (United States)

    Machado, Naila Aparecida de Godoi; Fonseca, Rodrigo Borges; Branco, Carolina Assaf; Barbosa, Gustavo Augusto Seabra; Fernandes Neto, Alfredo Júlio; Soares, Carlos José

    2007-08-01

    Bruxism is a pathological activity of the stomatognathic system that involves tooth grinding and clenching during parafunctional jaw movements. Clinical signs of bruxism are mostly related to dental wear and muscular and joint discomforts, but a large number of etiological factors can be listed, as local, systemic, psychological and hereditary factors. The association between bruxism, feeding and smoking habits and digestive disorders may lead to serious consequences to dental and related structures, involving dental alterations (wear, fractures and cracks), periodontal signs (gingival recession and tooth mobility) and muscle-joint sensitivity, demanding a multidisciplinary treatment plan. This paper presents a case report in which bruxism associated with acid feeding, smoking habit and episodes of gastric reflow caused severe tooth wear and great muscular discomfort with daily headache episodes. From the diagnosis, a multidisciplinary treatment plan was established. The initial treatment approach consisted of medical follow up with counseling on diet and smoking habits and management of the gastric disorders. This was followed by the installation of an interocclusal acrylic device in centric relation of occlusion (CRO) for reestablishment of the occlusal stability, vertical dimension of occlusion, anterior guides and return to normal muscle activity (90-day use approximately). After remission of initial symptoms, oral rehabilitation was implemented in CRO by means of full resin composite restorations and new interocclusal device for protection of restorations. Satisfactory esthetics, improved function and occlusal stability were obtained after oral rehabilitation. The patient has attended annual follow-ups for the past 2 years. The multidisciplinary treatment seems to be the key for a successful rehabilitation of severe cases of dental wear involving the association of different health disorders.

  2. Real-Time Estimation for Cutting Tool Wear Based on Modal Analysis of Monitored Signals

    Directory of Open Access Journals (Sweden)

    Yongjiao Chi

    2018-05-01

    Full Text Available There is a growing body of literature that recognizes the importance of product safety and the quality problems during processing. The working status of cutting tools may lead to project delay and cost overrun if broken down accidentally, and tool wear is crucial to processing precision in mechanical manufacturing, therefore, this study contributes to this growing area of research by monitoring condition and estimating wear. In this research, an effective method for tool wear estimation was constructed, in which, the signal features of machining process were extracted by ensemble empirical mode decomposition (EEMD and were used to estimate the tool wear. Based on signal analysis, vibration signals that had better linear relationship with tool wearing process were decomposed, then the intrinsic mode functions (IMFs, frequency spectrums of IMFs and the features relating to amplitude changes of frequency spectrum were obtained. The trend that tool wear changes with the features was fitted by Gaussian fitting function to estimate the tool wear. Experimental investigation was used to verify the effectiveness of this method and the results illustrated the correlation between tool wear and the modal features of monitored signals.

  3. Cost, performance, and esthetic impacts of an experimental forest road in Montana

    Science.gov (United States)

    Rulon B. Gardner

    1978-01-01

    An experimental logging road designed to minimize environmental and esthetic impact was constructed in northwest Montana. The road was single-lane (14-foot finished surface, 3-foot ditch), constructed along the contour. Esthetically, the single-lane experimental road was judged far superior to existing roads on the forest.

  4. Influence of curing rate on softening in ethanol, degree of conversion, and wear of resin composite

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Peutzfeldt, Anne; Asmussen, Erik

    2011-01-01

    PURPOSE: To investigate the effect of curing rate on softening in ethanol, degree of conversion, and wear of resin composites. METHOD: With a given energy density and for each of two different light-curing units (QTH or LED), the curing rate was reduced by modulating the curing mode. Thus......, the irradiation of resin composite specimens (Filtek Z250, Tetric Ceram, Esthet-X) was performed in a continuous curing mode and in a pulse-delay curing mode. Wallace hardness was used to determine the softening of resin composite after storage in ethanol. Degree of conversion was determined by infrared...... exposed to the pulse-delay curing mode were softer than resin composites exposed to continuous cure (Pconversion (P

  5. Esthetic modification of cast dental-ceramic restorations.

    Science.gov (United States)

    Campbell, S D

    1990-01-01

    The advantages and disadvantages of conventional opaque substructures (eg, metal ceramic restorations) used for creating esthetic complete crown restorations are reviewed, and the esthetic advantages of veneering a translucent crown (Dicor) are considered. An appropriate aluminous veneering porcelain was identified (Vitadur Veneer). This veneer porcelain was chosen to match the thermal coefficient of expansion of the cast glass-ceramic substructure. A flexural strength study was then completed and it showed no difference in the strength of the veneered and nonveneered translucent cast glass-ceramic specimens. Scanning electron microscopy revealed that the interface between the porcelain veneer and cast glass-ceramic substructure had no visible porosity and resulted in a continuous-appearing structure. Potential coping designs, as well as the clinical applications and ramifications of this modified crown, are discussed.

  6. Man-made New Orleans: some interactions between the physical and esthetic environments

    Science.gov (United States)

    Ronald F. Lockmann

    1977-01-01

    The relations between the physical environment and esthetic dimensions of the New Orleans cultural landscape are examined. The esthetic characteristics associated with New Orleans urban morphology are examined with respect to possible constraints by the physical environment. Salient townscape features such as street grid system, surface-drainage network, and spatial...

  7. Transparent magnesium aluminate spinel: a prospective biomaterial for esthetic orthodontic brackets.

    Science.gov (United States)

    Krishnan, Manu; Tiwari, Brijesh; Seema, Saraswathy; Kalra, Namitha; Biswas, Papiya; Rajeswari, Kotikalapudi; Suresh, Madireddy Buchi; Johnson, Roy; Gokhale, Nitin M; Iyer, Satish R; Londhe, Sanjay; Arora, Vimal; Tripathi, Rajendra P

    2014-11-01

    Adult orthodontics is recently gaining popularity due to its importance in esthetics, oral and general health. However, none of the currently available alumina or zirconia based ceramic orthodontic brackets meet the esthetic demands of adult patients. Inherent hexagonal lattice structure and associated birefringence limits the visible light transmission in polycrystalline alumina and make them appear white and non transparent. Hence focus of the present study was to assess the feasibility of using magnesium aluminate (MgAl2O4) spinel; a member of the transparent ceramic family for esthetic orthodontic brackets. Transparent spinel specimens were developed from commercially available white spinel powder through colloidal shaping followed by pressureless sintering and hot isostatic pressing at optimum conditions of temperature and pressure. Samples were characterized for chemical composition, phases, density, hardness, flexural strength, fracture toughness and optical transmission. Biocompatibility was evaluated with in-vitro cell line experiments for cytotoxicity, apoptosis and genotoxicity. Results showed that transparent spinel samples had requisite physico-chemical, mechanical, optical and excellent biocompatibility for fabricating orthodontic brackets. Transparent spinel developed through this method demonstrated its possibility as a prospective biomaterial for developing esthetic orthodontic brackets.

  8. Quantification of wear-time adherence of removable appliances in young orthodontic patients in relation to their BMI: a preliminary study.

    Science.gov (United States)

    Schott, Timm Cornelius; Ludwig, Björn

    2014-01-01

    The relationship between unhealthy body mass index (BMI) and adherence to orthodontic treatment with removable appliances has not previously been evaluated. The aim of this study was to quantify the association between BMI and wear time of removable orthodontic appliances and to evaluate BMI changes during orthodontic treatment. Fifty-three normal-weight and 39 overweight/obese children and adolescents (7-15 years old) undergoing orthodontic treatment with removable appliances were enrolled into the study. BMI categories were determined using standardized age-specific and sex-specific BMI criteria, using data measured at the beginning of therapy and once during orthodontic treatment. Wear times of removable appliances were measured at 15-minute intervals over a period of 5 months using implanted microelectronic sensors. Median wear-time values were used in the analysis with the Mann-Whitney U-test used to test statistical differences between groups. The median wear time of removable orthodontic appliances was 9.3 hours for normal-weight patients and 9.2 hours for overweight/obese patients. No statistically significant (P>0.05) or clinically relevant differences in usage or adherence were detected between normal-weight and overweight/obese patients. BMI did not influence wear time or behavior of removable orthodontic appliances by young patients. The majority of patients showed qualitative decreases in BMI during therapy. The orthodontic treatment of young patients with removable devices does not require BMI-dependent changes in the treatment strategy. However, the use of removable appliances during meal times raises the possibility of reducing food intake, and in this way the orthodontist may have an active role to play in weight reduction.

  9. Wear of micro end mills

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    This paper addresses the important issue of wear on micro end mills considering relevant metrological tools for its characterization and quantification. Investigation of wear on micro end mills is particularly difficult and no data are available in the literature. Small worn volumes cause large...... part. For this investigation 200 microns end mills are considered. Visual inspection of the micro tools requires high magnification and depth of focus. 3D reconstruction based on scanning electron microscope (SEM) images and stereo-pair technique is foreseen as a possible method for quantification...

  10. Esthetic Education in Teacher Education (LEEP).

    Science.gov (United States)

    Texas Tech Univ., Lubbock.

    The Lubbock Esthetic Education Program (LEEP) is being offered as a field-based experience which combines theory and practice. As an interdisciplinary arts-education program conducted by teams composed of arts and education faculty and graduate and undergraduate students of Texas Tech University, LEEP is concerned with developing esthetic…

  11. Multi-disciplinary approach for enhancing orthodontic esthetics – case report

    Directory of Open Access Journals (Sweden)

    Kalia A

    2015-08-01

    Full Text Available Ajit Kalia, Nasim Mirdehghan, Sonali Khandekar, Wasu Patil Department of Orthodontics, MA Rangoonwala Dental College, Pune, IndiaBackground: In contemporary dental care, an increasing number of adult patients are now seeking orthodontic treatment with the primary motive of improvement in appearance and achievement of esthetic smile. Proper recognition of the dental and facial defects at the outset of treatment is the most important key to esthetic success and is essential in satisfying the patient's needs. By following the rules of Golden proportion smiles can be made attractive, harmonious, symmetrical, and proportionate. Methodology: Consisted of 22-year-old girl who came for treatment of crowding in maxillary and mandibular arches, abnormal overjet and overbite and had unaesthetic peg lateral.Results: Non-extraction therapy was carried out since the patient had good soft tissue drape, alignment was achieved by expanding the arches and moving teeth in ideal axial inclination. Esthetic smile was attained using composite buildup of upper right peg lateral and minor adjunctive surgery (full thickness periodontal graft on lower right central incisor.Conclusion: The present case report orchestrates interrelationship between various branches of dentistry and orthodontics. It exhibits how multidisciplinary approach can be used to achieve ideal dental esthetics in a 22-year-old girl who was successfully treated for peg shaped lateral incisor, gingival recession, and unaesthetic smile. Keywords: adult orthodontics, peg lateral, gingival recession, golden proportion

  12. Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

    International Nuclear Information System (INIS)

    Zhao, W G; Qi, C X; Li, Y B; He, M Y

    2013-01-01

    Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

  13. Esthetic restorations of maxillary anterior teeth with orthodontic treatment and porcelain laminate veneers: a case report.

    Science.gov (United States)

    Moon, Ji-Eun; Kim, Sung-Hun; Han, Jung-Suk; Yang, Jae-Ho; Lee, Jai-Bong

    2010-06-01

    If orthodontists and restorative dentists establish the interdisciplinary approach to esthetic dentistry, the esthetic and functional outcome of their combined efforts will be greatly enhanced. This article describes satisfying esthetic results obtained by the distribution of space for restoration by orthodontic treatment and porcelain laminate veneers in uneven space between maxillary anterior teeth. It is proposed that the use of orthodontic treatment for re-distribution of the space and the use of porcelain laminate veneers to alter crown anatomy provide maximum esthetic and functional correction for patients with irregular interdental spacing.

  14. Tool wear modeling using abductive networks

    Science.gov (United States)

    Masory, Oren

    1992-09-01

    A tool wear model based on Abductive Networks, which consists of a network of `polynomial' nodes, is described. The model relates the cutting parameters, components of the cutting force, and machining time to flank wear. Thus real time measurements of the cutting force can be used to monitor the machining process. The model is obtained by a training process in which the connectivity between the network's nodes and the polynomial coefficients of each node are determined by optimizing a performance criteria. Actual wear measurements of coated and uncoated carbide inserts were used for training and evaluating the established model.

  15. Condition of esthetic component of motive activity in aerobic gymnastics

    Directory of Open Access Journals (Sweden)

    Valentina Todorova

    2017-02-01

    Full Text Available Purpose: to prove condition of esthetic component of motive activity of sportsmen in aerobic gymnastics at various stages of sports preparation. Material & Methods: analysis of video records, method of expert assessment, methods of mathematical statistics. Results: the level of criteria of esthetic component ("musicality", "dancing", "illustrative expressiveness", and "emotional expressiveness" with use of the offered rating scale is determined. Conclusions: indicators of motive activities of sportsmen for aerobic gymnastics are defined at various stages of sports preparation.

  16. Agave Chewing and Dental Wear: Evidence from Quids.

    Directory of Open Access Journals (Sweden)

    Emily E Hammerl

    Full Text Available Agave quid chewing is examined as a potential contributing behavior to hunter-gatherer dental wear. It has previously been hypothesized that the contribution of Agave quid chewing to dental wear would be observed in communities wherever phytolith-rich desert succulents were part of subsistence. Previous analysis of coprolites from a prehistoric agricultural site, La Cueva de los Muertos Chiquitos in Durango, Mexico, showed that Agave was a consistent part of a diverse diet. Therefore, quids recovered at this site ought to be useful materials to test the hypothesis that dental wear was related to desert succulent consumption. The quids recovered from the site were found to be largely derived from chewing Agave. In this study, the quids were found to be especially rich in phytoliths, and analysis of dental casts made from impressions left in the quids revealed flat wear and dental attrition similar to that of Agave-reliant hunter-gatherers. Based on evidence obtained from the analysis of quids, taken in combination with results from previous studies, it is determined that Agave quid chewing was a likely contributing factor to dental wear in this population. As such, our method provides an additional avenue of dental research in areas where quids are present.

  17. Esthetic evaluation of the facial profile in rehabilitated adults with complete bilateral cleft lip and palate.

    Science.gov (United States)

    Ferrari Júnior, Flávio Mauro; Ayub, Priscila Vaz; Capelozza Filho, Leopoldino; Pereira Lauris, José Roberto; Garib, Daniela Gamba

    2015-01-01

    To assess the facial esthetics of patients with complete bilateral cleft lip and palate, and to compare the judgment of raters related and unrelated to cleft care. The sample comprised 23 adult patients (7 women and 16 men) with a mean age of 26.1 years, rehabilitated at a single center. Standardized photographs of the right and left facial profile were taken of each patient and subjectively evaluated by 25 examiners: 5 orthodontists and 5 plastic surgeons with expertise in oral cleft rehabilitation, 5 orthodontists and 5 plastic surgeons without expertise in oral cleft rehabilitation, and 5 laypersons. The facial profiles were classified into 3 categories: esthetically unpleasant, esthetically acceptable, and esthetically pleasant. Intraexaminer and interexaminer agreements were evaluated with the Spearman correlation coefficient and Kendall coefficient of concordance. The differences between rater categories were analyzed using the Student-Newman-Keuls test (with P esthetically acceptable. Orthodontists and plastic surgeons related to oral cleft rehabilitation gave the best scores to the facial profiles, followed by layperson examiners and by orthodontists and plastic surgeons unrelated to oral cleft rehabilitation. The middle third of the face, the nose, and the upper lip were frequently pointed out as contributors to the esthetic impairment. The facial profile of rehabilitated adult patients with complete bilateral cleft lip and palate was considered esthetically acceptable because of morphologic limitations in the structures affected by the cleft. Laypersons and professionals unrelated to oral cleft rehabilitation seem to be more critical regarding facial esthetics than professionals involved with cleft rehabilitation. Copyright © 2015. Published by Elsevier Inc.

  18. [Esthetic analysis on immediate single-tooth implant restoration in anterior maxilla].

    Science.gov (United States)

    Li, Shao-wei; Wang, Guo-shi; Sha, Yan-zhi

    2015-10-01

    To evaluate the esthetic outcomes of immediate single-tooth implant restoration in anterior maxilla with the pink esthetic score (PES). Nine patients were treated with 9 Straumann implants by immediate single-tooth implant restoration in anterior maxilla. Assessment of PES after crown placement at 1 week (baseline) and 6 months after implantation was conducted. Statistical analysis was performed using SPSS 16.0 software package. Nine implants achieved a retention rate of 100%. PES for single-tooth implant was 10.33 ± 1.50 at 1 week and 11.44 ± 0.88 at 6 months after crown placement. The difference was significant(P=0.021). This study indicates that immediate single-tooth implant restoration in anterior maxilla is predictable. Immediate single-tooth implantation can result in good clinical esthetic results in most patients with single-tooth missing in anterior maxilla.

  19. An Island of Stability: Art Images and Natural Scenes – but Not Natural Faces – Show Consistent Esthetic Response in Alzheimer’s-Related Dementia

    Science.gov (United States)

    Graham, Daniel J.; Stockinger, Simone; Leder, Helmut

    2013-01-01

    Alzheimer’s disease (AD) causes severe impairments in cognitive function but there is evidence that aspects of esthetic perception are somewhat spared, at least in early stages of the disease. People with early Alzheimer’s-related dementia have been found to show similar degrees of stability over time in esthetic judgment of paintings compared to controls, despite poor explicit memory for the images. Here we expand on this line of inquiry to investigate the types of perceptual judgments involved, and to test whether people in later stages of the disease also show evidence of preserved esthetic judgment. Our results confirm that, compared to healthy controls, there is similar esthetic stability in early stage AD in the absence of explicit memory, and we report here that people with later stages of the disease also show similar stability compared to controls. However, while we find that stability for portrait paintings, landscape paintings, and landscape photographs is not different compared to control group performance, stability for face photographs – which were matched for identity with the portrait paintings – was significantly impaired in the AD group. We suggest that partially spared face-processing systems interfere with esthetic processing of natural faces in ways that are not found for artistic images and landscape photographs. Thus, our work provides a novel form of evidence regarding face-processing in healthy and diseased aging. Our work also gives insights into general theories of esthetics, since people with AD are not encumbered by many of the semantic and emotional factors that otherwise color esthetic judgment. We conclude that, for people with AD, basic esthetic judgment of artistic images represents an “island of stability” in a condition that in most other respects causes profound cognitive disruption. As such, esthetic response could be a promising route to future therapies. PMID:23471005

  20. Judgment of Nasolabial Esthetics in Cleft Lip and Palate Is Not Influenced by Overall Facial Attractiveness.

    Science.gov (United States)

    Kocher, Katharina; Kowalski, Piotr; Kolokitha, Olga-Elpis; Katsaros, Christos; Fudalej, Piotr S

    2016-05-01

    To determine whether judgment of nasolabial esthetics in cleft lip and palate (CLP) is influenced by overall facial attractiveness. Experimental study. University of Bern, Switzerland. Seventy-two fused images (36 of boys, 36 of girls) were constructed. Each image comprised (1) the nasolabial region of a treated child with complete unilateral CLP (UCLP) and (2) the external facial features, i.e., the face with masked nasolabial region, of a noncleft child. Photographs of the nasolabial region of six boys and six girls with UCLP representing a wide range of esthetic outcomes, i.e., from very good to very poor appearance, were randomly chosen from a sample of 60 consecutively treated patients in whom nasolabial esthetics had been rated in a previous study. Photographs of external facial features of six boys and six girls without UCLP with various esthetics were randomly selected from patients' files. Eight lay raters evaluated the fused images using a 100-mm visual analogue scale. Method reliability was assessed by reevaluation of fused images after >1 month. A regression model was used to analyze which elements of facial esthetics influenced the perception of nasolabial appearance. Method reliability was good. A regression analysis demonstrated that only the appearance of the nasolabial area affected the esthetic scores of fused images (coefficient = -11.44; P esthetic evaluation can be performed on images of full faces.

  1. Reduction of Erosion Wear of Mean Pressure Cylinder of Steam Turbines Operating Beyond Critical Parameters

    Directory of Open Access Journals (Sweden)

    V. P. Kascheev

    2009-01-01

    Full Text Available The paper considers problems leading to erosion wear of flowing part of a mean pressure turbine cylinder operating beyond critical parameters. Explanation of erosion wear of flowing part of a mean pressure turbine cylinder which is proved in practice and recommendations for wear reduction are given in the paper

  2. Influence of bimaxillary protrusion on the perception of smile esthetics.

    Science.gov (United States)

    Almutairi, Terki K; Albarakati, Sahar F; Aldrees, Abdullah M

    2015-01-01

    To evaluate the impact of bimaxillary protrusion on smile esthetics as perceived by dental professionals and laypersons. One hundred and fifty evaluators, equally distributed into their respective panels (orthodontists, general dentists, and laypersons), participated in this cross-sectional study conducted in April to December 2012 in Riyadh, Saudi Arabia. The patient sample consisted of 14 female patients divided equally into 2 groups: bimaxillary protrusion patients, and patients who have had 4-premolar extraction treatment. Two standardized photographs (frontal and three-quarter close-up smile views), and a lateral cephalogram were taken for each patient. The evaluators were asked to rate the attractiveness of each photo according to a 100-mm visual analog scale. These esthetic ratings were correlated with the patients' cephalometric measurements. The bimaxillary protrusion group was rated significantly as less attractive than the treatment group by each evaluator panel. Panel comparison showed that laypeople were less receptive of bimaxillary protrusion than dental professionals. Frontal and three-quarter views of the same smiles were not similarly rated for esthetic perceptions. Correlational analysis revealed that the dentoalveolar measurement with the highest significant negative correlation to the smile esthetics was the upper incisors to palatal plane (U1-PP) angle. Patients with bimaxillary protrusion were found to be less attractive than patients who were treated for the condition. This was especially evident among the laypersons. An increase in the upper incisor inclination, as well as a decrease in the interincisal angle compounds the bimaxillary effect. 

  3. [Esthetic nutrition: body and beauty enhancement through nutritional care].

    Science.gov (United States)

    Witt, Juliana da Silveira Gonçalves Zanini; Schnider, Aline Petter

    2011-09-01

    Nowadays, there is an increasing quest for beauty and the models proposed by fashion goods and service segments, to achieve the perfect body. The standard of beauty corresponds to a thin body, without considering health aspects. The number of women who go on diets to control weight is increasing; and taking this into consideration the objective of this study is to conduct a bibliographical review and extract data on esthetics and body image to support the practice of nutritional care. Socio-cultural aspects, which motivate the quest for the perfect body, as well as body, beauty, esthetics, nutritional counseling and cognitive behavior therapy were examined in this survey. On the basis of this work, it is possible to conclude that the continuing obsession with the body may lead the person to go on diets and other drastic methods to control weight, such as surgical procedures. In this respect, nutritional care is far more than merely recommending a standard diet or giving information, as it represents providing an effective model for nutritional reeducation, prioritizing improvement in the style and quality of life. This article provides data about enhancing esthetics and beauty by means of appropriate nutrition.

  4. DEVELOPMENT OF SENSITIVITY TO ESTHETIC VALUES.

    Science.gov (United States)

    CHILD, IRVIN L.

    THE OBJECTS OF THIS STUDY WERE (1) TO DETERMINE THE DEVELOPMENT OF AVERAGE ESTHETIC SENSITIVITY TO VISUAL ART THROUGH THE ELEMENTARY AND SECONDARY SCHOOL YEARS AND (2) TO DETERMINE IF APPROPRIATE TRAINING PROCEDURES WOULD LEAD CHILDREN TO DISCRIMINATE BETWEEN WORKS CONSIDERED BETTER OR POORER BY EXPERTS. CHILDREN FROM GRADES 1 TO 12 WERE PRESENTED…

  5. Translucency changes of direct esthetic restorative materials after curing, aging and treatment

    Directory of Open Access Journals (Sweden)

    Yong-Keun Lee

    2016-11-01

    Full Text Available The purpose of this article was to review the changes in translucency of direct esthetic restorative materials after curing, aging and treatment. As a criterion for the evaluation of clinical translucency changes, visual perceptibility threshold in translucency parameter difference (ΔTP of 2 was used. Translucency changes after curing were perceivable depending on experimental methods and products (largest ΔTP in resin composites = 15.9. Translucency changes after aging were reported as either relatively stable or showed perceivable changes by aging protocols (largest ΔTP in resin composites = -3.8. Translucency changes after curing, aging and treatment were perceivable in several products and experimental methods. Therefore, shade matching of direct esthetic materials should be performed considering these instabilities of translucency in direct esthetic materials.

  6. A conservative approach for restoring anterior guidance: a case report.

    Science.gov (United States)

    Pontons-Melo, Juan Carlos; Pizzatto, Eduardo; Furuse, Adilson Yoshio; Mondelli, José

    2012-06-01

    One of the most common dental problems in today's clinics is tooth wear, specifically when related to bruxism. In such cases, the esthetics of anterior teeth may be compromised when excessive wear to the incisal surfaces occurs. Anterior tooth wear resulting from parafunctional bruxism can be conservatively treated with the use of direct resin composite restorations. This restorative approach has the advantages of presenting good predictability, load resistance, acceptable longevity, preservation of healthy dental tissues, and lower cost when compared with indirect restorations. The use of resin composites to solve esthetic problems, however, requires skill and practice. Thus, the present article demonstrates a conservative approach for restoring the esthetics and function of worn anterior teeth with the aid of direct resin composite restorations and selective occlusal adjustment. A conservative approach to restore anterior teeth with excessive wear is possible with direct resin composites. © 2011 Wiley Periodicals, Inc.

  7. Does Wearing Textured Insoles during Non-class Time Improve Proprioception in Professional Dancers?

    Science.gov (United States)

    Steinberg, N; Tirosh, O; Adams, R; Karin, J; Waddington, G

    2015-11-01

    This study sought to determine whether textured insoles inserted in the sports shoes of young dancers improved their inversion and eversion ankle movement discrimination. 26 ballet dancers (14 female, 12 male) from the Australian Ballet School, ages 14-19 years, were divided into 2 groups according to sex and class levels. During the first 4 weeks, the first intervention group (GRP1) was asked to wear textured insoles in their sports shoes during non-class periods, and the second intervention group (GRP2) followed standard practice. In the next 4 weeks, GRP2 was asked to wear the textured insoles and GRP1 did not wear the textured insoles. Participants were tested pre-intervention, after 4 weeks, and at 8 weeks for both inversion and eversion ankle discrimination. In both inversion and eversion testing positions, interaction was found between the 2 groups and the 3 testing times (p<0.001), with significant differences between the first testing and the second testing (p=0.038 and p=0.019, respectively), and between the third testing and the second testing (p=0.003 and p=0.029, respectively). In conclusion, the stimulation to the proprioceptive system arising from textured insoles worn for 4 weeks was sufficient to improve the ankle proprioception of ballet dancers, in both inversion and eversion movements. © Georg Thieme Verlag KG Stuttgart · New York.

  8. Gear Tooth Wear Detection Algorithm

    Science.gov (United States)

    Delgado, Irebert R.

    2015-01-01

    Vibration-based condition indicators continue to be developed for Health Usage Monitoring of rotorcraft gearboxes. Testing performed at NASA Glenn Research Center have shown correlations between specific condition indicators and specific types of gear wear. To speed up the detection and analysis of gear teeth, an image detection program based on the Viola-Jones algorithm was trained to automatically detect spiral bevel gear wear pitting. The detector was tested using a training set of gear wear pictures and a blind set of gear wear pictures. The detector accuracy for the training set was 75 percent while the accuracy for the blind set was 15 percent. Further improvements on the accuracy of the detector are required but preliminary results have shown its ability to automatically detect gear tooth wear. The trained detector would be used to quickly evaluate a set of gear or pinion pictures for pits, spalls, or abrasive wear. The results could then be used to correlate with vibration or oil debris data. In general, the program could be retrained to detect features of interest from pictures of a component taken over a period of time.

  9. Esthetic smile preferences and the orientation of the maxillary occlusal plane.

    Science.gov (United States)

    Kattadiyil, Mathew T; Goodacre, Charles J; Naylor, W Patrick; Maveli, Thomas C

    2012-12-01

    The anteroposterior orientation of the maxillary occlusal plane has an important role in the creation, assessment, and perception of an esthetic smile. However, the effect of the angle at which this plane is visualized (the viewing angle) in a broad smile has not been quantified. The purpose of this study was to assess the esthetic preferences of dental professionals and nondentists by using 3 viewing angles of the anteroposterior orientation of the maxillary occlusal plane. After Institutional Review Board approval, standardized digital photographic images of the smiles of 100 participants were recorded by simultaneously triggering 3 cameras set at different viewing angles. The top camera was positioned 10 degrees above the occlusal plane (camera #1, Top view); the center camera was positioned at the level of the occlusal plane (camera #2, Center view); and the bottom camera was located 10 degrees below the occlusal plane (camera #3, Bottom view). Forty-two dental professionals and 31 nondentists (persons from the general population) independently evaluated digital images of each participant's smile captured from the Top view, Center view, and Bottom view. The 73 evaluators were asked individually through a questionnaire to rank the 3 photographic images of each patient as 'most pleasing,' 'somewhat pleasing,' or 'least pleasing,' with most pleasing being the most esthetic view and the preferred orientation of the occlusal plane. The resulting esthetic preferences were statistically analyzed by using the Friedman test. In addition, the participants were asked to rank their own images from the 3 viewing angles as 'most pleasing,' 'somewhat pleasing,' and 'least pleasing.' The 73 evaluators found statistically significant differences in the esthetic preferences between the Top and Bottom views and between the Center and Bottom views (Pgender, profession, and race. The esthetic preference for the maxillary occlusal plane was influenced by the viewing angle with the

  10. Incisors’ proportions in smile esthetics

    Science.gov (United States)

    Alsulaimani, Fahad F; Batwa, Waeil

    2013-01-01

    Aims: To determine whether alteration of the maxillary central and lateral incisors’ length and width, respectively, would affect perceived smile esthetics and to validate the most esthetic length and width, respectively, for the central and lateral incisors. Materials and Methods: Photographic manipulation was undertaken to produce two sets of photographs, each set of four photographs showing the altered width of the lateral incisor and length of the central length. The eight produced photographs were assessed by laypeople, dentists and orthodontists. Results: Alteration in the incisors’ proportion affected the relative smile attractiveness for laypeople (n=124), dentists (n=115) and orthodontists (n=68); dentists and orthodontists did not accept lateral width reduction of more than 0.5 mm (P<0.01), which suggests that the lateral to central incisor width ratio ranges from 54% to 62%. However, laypeople did not accept lateral width reduction of more than 1 mm (P<0.01), widening the range to be from 48% to 62%. All groups had zero tolerance for changes in central crown length (P<0.01). Conclusion: All participants recognized that the central incisors’ length changes. For lateral incisors, laypeople were more tolerant than dentists and orthodontists. This suggests that changing incisors’ proportions affects the relative smile attractiveness. PMID:24987650

  11. Which Factors Affect Dental Esthetics and Smile Attractiveness in Orthodontically Treated Patients?

    Science.gov (United States)

    Heravi, Farzin; Rashed, Roozbeh; Zarrabi, Mohammad Javad; Setayesh, Yasin

    2015-01-01

    Objectives: This study aimed to find the factors that affect dental esthetics and smile attractiveness in orthodontically treated patients according to laypeople’s judgment, and to determine whether there is any relationship between dental and smile esthetics. Materials and Methods: Using the Q-sort technique, 60 laypersons (30 males, 30 females) rated dental and smile photographs of 48 orthodontically treated patients based on their degree of attractiveness. Dental and smile parameters of each rated image were measured by Smile Analyzer software. The Student’s t-test and chi-square test were used to compare dental and smile parameters between attractive and unattractive images. The logistic regression was used to assess which variables predicted dental and smile esthetics in treated individuals. Results: The philtral to commissural height ratio and gingival display were significantly different in attractive and unattractive smiles (P=0.003 and P=0.02, respectively). None of the dental variables were found to be a determinant of dental esthetics at the end of the orthodontic treatment (P>0.05). According to the judgment of all raters (female and male) and the male raters’ judgment, smile attractiveness could be predicted by philtral to commissural height ratio and buccal corridor ratio (Pesthetics and smile attractiveness in orthodontically treated patients (P>0.05). Conclusion: The philtral to commissural height ratio and buccal corridor ratio can be considered as predictors of smile attractiveness in orthodontically treated patients. Achieving dental esthetics at the end of orthodontic treatment does not guarantee smile attractiveness. PMID:26877739

  12. IMPACT OF DENTAL TRAUMA AND ESTHETIC IMPAIRMENT ON THE QUALITY OF LIFE OF PRESCHOOL CHILDREN

    Science.gov (United States)

    Gonçalves, Bruna Miroski; Dias, Loraine Fernandes; Pereira, Carla da Silva; Ponte, Marcos Ximenes; Konrath, Andréa Cristina; Bolan, Michele da Silva; Cardoso, Mariane

    2017-01-01

    ABSTRACT Objective: To evaluate the impact of dental trauma and impaired esthetics on the quality of life (QoL) of preschool children and their relatives. Methods: Study conducted with 192 children aged 2 to 5 years in 11 preschools in Florianópolis, Santa Catarina, South of Brazil. Parents/caregivers completed a questionnaire on quality of life (Brazilian version of the Early Childhood Oral Health Impact Scales - B-ECOHIS), a socioeconomic survey, and then answered specific questions related to dental trauma. The subjects were examined by three accordant examiners (Kappa>0.7). Dental trauma was evaluated on the basis of indexes adopted by the World Health Organization, and esthetic impairment was then classified. Data were descriptively analyzed and put to bivariate analysis by chi-square and Fisher tests, with significance level at 5%. Results: The prevalence of dental trauma was 62.5% with 15.6% of esthetic impairment. Almost 12% of parents reported impact on the quality of life of their children. Dental trauma was not significantly associated with gender, age or QoL. Crown color change by trauma was associated with esthetic impairment. Also esthetic impairment had a negative impact on QoL (pEsthetic impairment had a negative impact on children’s quality of life, while dental trauma was not associated to it. PMID:28977132

  13. The esthetic preference of Chinese typefaces--an event-related potential study.

    Science.gov (United States)

    Li, Rui; Qin, Ruilin; Zhang, Junsong; Wu, Junjie; Zhou, Changle

    2015-02-19

    Emotional stimuli such as pictures, logos, geometric shapes, etc can evoke human esthetic preference from previous neuroesthetic studies. Chinese characters can be considered as emotional stimuli as they have an important property: typeface. Intuitively, the emotional meaning of Chinese characters can cause esthetic preference. However, whether a typeface can cause esthetic preference or not from an empirical perspective is still unknown. To address this issue, participants׳ event-related potential (ERP) waves are recorded while they are presented a series of Chinese characters in different typefaces. Participants are asked to distinguish specific target from the others. Afterwards, from the Chinese characters presented in this task, participants are asked individually to select the characters they like the most and dislike the most. By recording the ERP responses (a response of implicit preference to Chinese characters themselves) during the experiment to different typefaces of Chinese characters, we find a significant difference between disliked and all characters in the frontal-central area in the 200-300 ms window after the stimulus׳ onset. In the 400-600 ms window, after the stimulus׳ onset, a significant bias for disliked characters emerges in frontal, central, parietal and occipital areas. Our results suggest that people could make a rapid, implicit esthetic preference for the typefaces of Chinese characters. Copyright © 2014. Published by Elsevier B.V.

  14. Comparison of White and Chinese perception of esthetic Chinese lip position.

    Science.gov (United States)

    Chong, Hui Theng; Thea, Kim Wei; Descallar, Joseph; Chen, Yong; Dalci, Oyku; Wong, Ricky; Darendeliler, M Ali

    2014-03-01

    To compare the esthetic preference of White and Chinese judges with regard to Chinese lip position. The profile images of a dental and skeletal Class I Chinese adult male and female were digitally adjusted to Chinese mean values. The lip profile was adjusted with the upper and lower lip at the mean distance from the Ricketts' E-line. These images were used as baseline images and were further digitally manipulated to generate six additional images with the upper and lower lip such that they lay 0.5, 1.0, and 2.0 standard deviations (SDs) in front of or behind the E-line. An additional image was modified based on a White mean value. The images were viewed and ranked by 251 White and Chinese judges (dentists and laypersons) in Australia and China. Significantly more Chinese judges ranked the retrusive profiles higher than the White judges. The White judges also ranked the profile image adjusted to -0.5 SD as the most esthetic for both the female and male, while the Chinese judges ranked the -1.0 SD profile as the most esthetic. The ethnicity of the judges is a significant factor influencing the perception of esthetic lip position. The Chinese judges prefer a more retrusive profile and are more likely to rate a protrusive profile as unacceptable, compared with the White judges.

  15. Effects of Art/Design Education on Meta-Esthetics Consciousness of Fine Arts Students

    Science.gov (United States)

    Tataroglu, Eylem

    2015-01-01

    The objectives of the present study were to determine the consciousness and sensitivity levels of Fine Arts students about the meta-esthetics as a consumer and producer and to determine the effects of the courses they took on their meta-esthetic consciousness. The research universe was composed of fine art faculties of the foundation universities…

  16. A Study on Optimal Wear Design for a Gerotor Pump

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Soon Man; Nam, Hyoung Chul; Lu, Lei; Shin, Joong Ho [Changwon National University, Changwon (Korea, Republic of)

    2009-01-15

    A disadvantage in the design of gerotor pump is a lack of parts that can be adjusted to compensate for wear in the rotor set, and as a consequence, it causes a sharp reduction of efficiency. In this paper, an attempt has been made to reduce the wear rate between the rotors of a gerotor pump. To do this, floating genetic algorithm (FGA) is used as an optimization technique for minimizing the wear rate proportional factor (WRPF). The result shows that the wear rate can be reduced considerably, e.g. approximately 8% in this paper, throughout the optimization using FGA.

  17. Efficacy of split hours part-time patching versus continuous hours part-time patching for treatment of anisometropic amblyopia in children: a pilot study.

    Science.gov (United States)

    Sachdeva, Virender; Mittal, Vaibhev; Kekunnaya, Ramesh; Gupta, Amit; Rao, Harsha L; Mollah, Joseph; Sontha, Anand; Gunturu, Rekha; Rao, B Venkateshwar

    2013-07-01

    To compare efficacy of 'split hours part-time patching' and 'continuous hours part-time patching' for the treatment of anisometropic amblyopia. We designed a prospective, interventional, non-randomised, comparative pilot study involving children between 4 and 11 years of age with anisometropic amblyopia who were treated with either continuous wear (Group A) or split hours part-time patching (Group B) as per parents wish, after appropriate discussion with the parents. Children were followed-up for the improvement in visual acuity and the compliance at each follow-up visit. 44 and 24 children were recruited in Group A and Group B, respectively (mean ± SD baseline BCVA of the amblyopic eye: 0.99 ± 0.32 and 0.95 ± 0.23 logMAR, respectively). BCVA (adjusted for baseline BCVA and age) at 3 months in Group A (0.59 ± 0.24) was comparable (p=0.08) with that in Group B (0.71 ± 0.24). This was same even at 6 months (0.51 ± 0.25 in Group A and 0.59 ± 0.25 in Group B, p=0.25). The improvement in BCVA at 3 months was also comparable (p=0.06) in Group A (0.39 ± 0.23) and Group B (0.26 ± 0.23). The improvement in BCVA at 6 months was also comparable (p=0.14) in Group A (0.47 ± 0.26) and Group B (0.37 ± 0.26). Both patching regimens lead to significant and comparable improvement in BCVA in anisometropic amblyopia up to 6 months of follow-up.

  18. Wear behavior of pressable lithium disilicate glass ceramic.

    Science.gov (United States)

    Peng, Zhongxiao; Izzat Abdul Rahman, Muhammad; Zhang, Yu; Yin, Ling

    2016-07-01

    This article reports effects of surface preparation and contact loads on abrasive wear properties of highly aesthetic and high-strength pressable lithium disilicate glass-ceramics (LDGC). Abrasive wear testing was performed using a pin-on-disk device in which LDGC disks prepared with different surface finishes were against alumina pins at different contact loads. Coefficients of friction and wear volumes were measured as functions of initial surface finishes and contact loads. Wear-induced surface morphology changes in both LDGC disks and alumina pins were characterized using three-dimensional laser scanning microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results show that initial surface finishes of LDGC specimens and contact loads significantly affected the friction coefficients, wear volumes and wear-induced surface roughness changes of the material. Both wear volumes and friction coefficients of LDGC increased as the load increased while surface roughness effects were complicated. For rough LDGC surfaces, three-body wear was dominant while for fine LDGC surfaces, two-body abrasive wear played a key role. Delamination, plastic deformation, and brittle fracture were observed on worn LDGC surfaces. The adhesion of LDGC matrix materials to alumina pins was also discovered. This research has advanced our understanding of the abrasive wear behavior of LDGC and will provide guidelines for better utilization and preparation of the material for long-term success in dental restorations. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 968-978, 2016. © 2015 Wiley Periodicals, Inc.

  19. Effect and sustainability of part-time occlusion therapy for patients with anisometropic amblyopia aged > or =8 years.

    Science.gov (United States)

    Hwang, D J; Kim, Y J; Lee, J Y

    2010-09-01

    To study the effect and long-term sustainability of part-time occlusion therapy for anisometropic amblyopia after 8 years of age. A total of 41 anisometropic amblyopes aged > or =8 years were analysed. In six patients, best-corrected visual acuity (BCVA) of amblyopic eye improved more than two lines within 2 weeks of full-time spectacle wear. The remaining patients were assigned to perform part-time patching during out-of-school hours. Long-term results were assessed in patients who were observed over 1 year after the end of the treatment. Among 35 patients, four dropped out, refusing further treatment, and one changed to atropine penalisation. The part-time patching schedule was completed in 30 patients. 90% of patients (27/30) complied well. Mean BCVA in the amblyopic eye improved significantly (ppart-time occlusion treatment in school-aged amblyopes, which had been carried out after school hours, was successful and the effect was sustained in most cases.

  20. Influence of ageing time on hardness, microstructure and wear behaviour of AISI2507 super duplex stainless steel

    Science.gov (United States)

    Davanageri, Mahesh; Narendranath, S.; Kadoli, Ravikiran

    2017-08-01

    The effect of ageing time on hardness, microstructure and wear behaviour of super duplex stainless AISI 2507 is examined. The material was solution treated at 1050 °C and water quenched, further the ageing has been carried out at 850 °C for 30 min, 60 min and 90 min. The chromium (Cr) and molybdenum (Mo) enriched intermetallic sigma phase (σ) were found to precipitate at the ferrite/austenite interface and within the ferrite region. The concentration of intermetallic sigma phase (σ), which was quantified by a combination of scanning electron microscopy and image analysis, increases with increasing ageing time, leading to significant increase in the hardness. The x-ray diffraction (XRD) and energy dispersive x-ray (EDX) was employed to investigate the element distribution and phase identification. Wear characterstics of the aged super duplex stainless steel were measured by varying normal loads, sliding speeds, sliding distance and compared with solution treated (as-cast) specimens. Scanning electron microscopy was used to assist in analysis of worn out surfaces. The outcomes suggested that the increase in percentage of sigma phase increases hardness and wear resistance in heat-treated specimens compared to solution treated specimens (as-cast).

  1. 3D FEM Simulation of Flank Wear in Turning

    Science.gov (United States)

    Attanasio, Aldo; Ceretti, Elisabetta; Giardini, Claudio

    2011-05-01

    This work deals with tool wear simulation. Studying the influence of tool wear on tool life, tool substitution policy and influence on final part quality, surface integrity, cutting forces and power consumption it is important to reduce the global process costs. Adhesion, abrasion, erosion, diffusion, corrosion and fracture are some of the phenomena responsible of the tool wear depending on the selected cutting parameters: cutting velocity, feed rate, depth of cut, …. In some cases these wear mechanisms are described by analytical models as a function of process variables (temperature, pressure and sliding velocity along the cutting surface). These analytical models are suitable to be implemented in FEM codes and they can be utilized to simulate the tool wear. In the present paper a commercial 3D FEM software has been customized to simulate the tool wear during turning operations when cutting AISI 1045 carbon steel with uncoated tungsten carbide tip. The FEM software was improved by means of a suitable subroutine able to modify the tool geometry on the basis of the estimated tool wear as the simulation goes on. Since for the considered couple of tool-workpiece material the main phenomena generating wear are the abrasive and the diffusive ones, the tool wear model implemented into the subroutine was obtained as combination between the Usui's and the Takeyama and Murata's models. A comparison between experimental and simulated flank tool wear curves is reported demonstrating that it is possible to simulate the tool wear development.

  2. A new methodology for predictive tool wear

    Science.gov (United States)

    Kim, Won-Sik

    An empirical approach to tool wear, which requires a series of machining tests for each combination of insert and work material, has been a standard practice for industries since early part of the twentieth century. With many varieties of inserts and work materials available for machining, the empirical approach is too experiment-intensive that the demand for the development of a model-based approach is increasing. With a model-based approach, the developed wear equation can be extended without additional machining experiments. The main idea is that the temperatures on the primary wear areas are increasing such that the physical properties of the tool material degrade substantially and consequently tool wear increases. Dissolution and abrasion are identified to be the main mechanisms for tool wear. Flank wear is predominantly a phenomenon of abrasion as evident by the presence of a scoring mark on the flank surface. Based on this statement, it is reasonable to expect that the flank-wear rate would increase with the content of hard inclusions. However, experimental flank wear results did not necessary correspond to the content of cementite phase present in the steels. Hence, other phenomena are believed to significantly affect wear behavior under certain conditions. When the cutting temperature in the flank interface is subjected to high enough temperatures, pearlitic structure austenizes. During the formation of a new austenitic phase, the existing carbon is dissolved into the ferrite matrix, which will reduce the abrasive action. To verify the austenitic transformation, turning tests were conducted with plain carbon steels. The machined surface areas are imaged using X-ray diffraction the Scanning Electron Microscope (SEM) and the Transmission Electron Microscope (TEM). On the other hand, crater wear occurs as a result of dissolution wear and abrasive wear. To verify the wear mechanisms of crater wear, various coating inserts as well as uncoated inserts were

  3. Probabilistic Analysis of Wear of Polymer Material used in Medical Implants

    Directory of Open Access Journals (Sweden)

    T. Goswami

    2016-05-01

    Full Text Available Probabilistic methods are applied to the study of fatigue wear of sliding surfaces. A variance of time to failure (to occurrence of maximum allowable wear depth is evaluated as a function of a mean wear rate of normal wear and a size of wear particles. A method of estimating probability of failure-free work during a certain time interval (reliability is presented. An effect of the bedding-in phase of wear on the reliability is taken into account. Experimental data for Ultra High Molecular Weight Polyethylene (UHMWPE cups of artificial hip implants is used to make numerical calculations.

  4. Tool Wear Analysis on Five-Axis Flank Milling for Curved Shape Part – Full Flute and Ground Shank End Mill

    Directory of Open Access Journals (Sweden)

    Syahrul Azwan Sundi

    2017-01-01

    Full Text Available This paper is a study on full flute (extra-long tool and ground shank end mill wear analysis by utilizing five-axis CNC to implement flank milling strategy on curved shape part. Five-axis machining eases the user to implement variations of strategy such as flank milling. Flank milling is different from point milling. Point milling cuts materials by using the tip of the tool whereas the flank milling uses the cutting tool body to cut material. The type of cutting tool used was end mill 10 mm diameter with High Speed Steel (HSS material. One factor at a time was utilized to analyze the overall data. Feed rate and spindle speed were the two main factors that been set up equally for both full flute and ground shank end mill. At the end of this research, the qualitative analysis based on tool wear between full flute and ground shank end mill is observed. Generally, both types of cutting tools showed almost the same failure indication such as broken edge or chipped off edge, formation of pinned hole on the surface and serration formation or built-up edge (BUE on the primary flute. However, the results obtained from the enlarged images which were captured by Optical Microscope indicated that, the ground shank end mill is better than the full flute end mill.

  5. Crowns to create esthetics for mal-aligned central incisors: a case report.

    Science.gov (United States)

    Savadi, Ravindra C; Savadi, Anupama R; Kumar, Preeti Satheesh

    2011-06-01

    This case report describes the smile design of crowded upper central anteriors in a female patient aged 25 years. The patient wanted the correction to be completed in a short period of time. A smile design schedule was drawn up involving root canal treatment of the central incisors and placing posts in both the teeth. All ceramic crowns were then fabricated to establish a very satisfactory and pleasing esthetics.

  6. Crowns to Create Esthetics for Mal-Aligned Central Incisors: A Case Report

    OpenAIRE

    Savadi, Ravindra C.; Savadi, Anupama R.; Kumar, Preeti Satheesh

    2011-01-01

    This case report describes the smile design of crowded upper central anteriors in a female patient aged 25 years. The patient wanted the correction to be completed in a short period of time. A smile design schedule was drawn up involving root canal treatment of the central incisors and placing posts in both the teeth. All ceramic crowns were then fabricated to establish a very satisfactory and pleasing esthetics.

  7. Investigation of machining damage and tool wear resulting from drilling powder metal aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Fell, H.A. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

    1997-05-01

    This report documents the cutting of aluminum powder metallurgy (PM) parts for the North Carolina Manufacturing Extension Partnership. The parts, an aluminum powder metal formulation, were supplied by Sinter Metals Inc., of Conover, North Carolina. The intended use of the alloy is for automotive components. Machining tests were conducted at Y-12 in the machine shop of the Skills Demonstration Center in Building 9737. Testing was done on June 2 and June 3, 1997. The powder metal alloy tested is very abrasive and tends to wear craters and produce erosion effects on the chip washed face of the drills used. It also resulted in huge amounts of flank wear and degraded performance on the part of most drills. Anti-wear coatings on drills seemed to have an effect. Drills with the coating showed less wear for the same amount of cutting. The usefulness of coolants and lubricants in reducing tool wear and chipping/breakout was not investigated.

  8. Dental wear, wear rate, and dental disease in the African apes.

    Science.gov (United States)

    Elgart, Alison A

    2010-06-01

    The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

  9. Tooth wear

    Directory of Open Access Journals (Sweden)

    Tušek Ivan

    2014-01-01

    surfaces. Attrition of teeth (attritio dentium represents teeth wear during mastication, friction on the tooth or teeth during parafunctional mandibular movements (bruxism, but without the abrasive effect. Dental erosion (erosio dentium or corrosive wear is a progressive, irreversible loss of dental hard tissue resulting from the effect of acids and /or chelation in the mouth, but without the participation of bacteria. Acids, of either exogenous or endogenous origin (peptic ulcer, gastritis, or bulimia, anoreksia nervosa, that come into the mouth can lead to different clinical manifestations of erosion depending on the time of exposure, the microstructure of teeth, buffering capacity, the amount of saliva and other factors. The changes are visible on the palatal surfaces of upper anterior teeth and, in severe cases, the lingual surfaces of posterior teeth. Occupational dental erosion occurs during exposure to industrial gases that contain hydrochloric or sulfuric acids, as well as the acids used in galvanizing and manufacture of battery and weapons. Due to the multifactorial nature of erosive tooth wear preventive measures must be applied taking into account chemical and biological factors as well as the patient's behavior associated with the etiology and pathogenesis of erosion. It is recommended to consume food and drinks that stimulate the secretion of large amounts of saliva base; to use neutral or alkaline mouthwash, and to chew sugar-free gum; to apply adequate oral hygiene (soft brushes, non-abrasive tooth paste, proper washing technique and not to consume aciding food and carbonated soft drinks and fizzy drinks in a great amount and frequently. It is necessary to apply preparations with high content of fluoride, and lubricant of tooth wear (powder CaF, CaF mixture and olive oil, and asset-based titanium tetrafluoride and casein-calcium phosphate. Commercial tooth paste that contains CPP-ACP (casein phosphopeptide-amorphous calcium phosphate and calcium phosphate

  10. Reliability modelling for wear out failure period of a single unit system

    OpenAIRE

    Arekar, Kirti; Ailawadi, Satish; Jain, Rinku

    2012-01-01

    The present paper deals with two time-shifted density models for wear out failure period of a single unit system. The study, considered the time-shifted Gamma and Normal distributions. Wear out failures occur as a result of deterioration processes or mechanical wear and its probability of occurrence increases with time. A failure rate as a function of time deceases in an early failure period and it increases in wear out period. Failure rates for time shifted distributions and expression for m...

  11. Width/Length Ratio in Maxillary Anterior Teeth. Comparative Study of Esthetic Preferences among Professionals and Laypersons.

    Science.gov (United States)

    Álvarez-Álvarez, Lorena; Orozco-Varo, Ana; Arroyo-Cruz, Gema; Jiménez-Castellanos, Emilio

    2017-05-17

    Many studies have examined the esthetic preferences of professionals in the maxillary anterior region; however, only a few have taken into account the ratios that are more frequent within the population or other ratios suggested in the literature as ideal. Previous studies also failed to compare them with the esthetic preferences of the lay population with regards to the smile. The purpose of this study is to highlight the differences when perceiving the esthetics of smiles between general dentists and laypersons, and linking them with the width/length of the maxillary anterior teeth. Photographs of the full face of a female subject were modified with Photoshop CS regarding the length/width relationships of the 6 maxillary anterior teeth. The three modifications made were: (a) 80% length/width, (b) 85%, length/width, and (c) 85% length/width in central incisors, 80% length/width in lateral incisors and canines. Three sequences of photograph pairs were created with different ratios and presented in PowerPoint to a sample of 100 general dentists and 100 laypersons. The ratio considered as the most esthetic by the majority of the judges was 85% for central incisors and 80% for lateral incisors and canines, with a statistically significant difference (p esthetic preferences of the studied populations either due to gender or professional experience of the dentists (p > 0.01). According to the results obtained in this study, professionals and laypersons considered a width/length ratio of 85% for maxillary central incisors and 80% for lateral incisors and canines as the most esthetic for maxillary anterior teeth. These results do not support findings from other studies previously published with similar ratios in central incisors, lateral incisors, and canines. Today clinicians practice in a treatment environment where not only function and utility but also esthetics is demanded in almost every procedure. Restoring/maintaining function is considered essential in any

  12. Vibration and wear prediction for steam generator tubes: Final report

    International Nuclear Information System (INIS)

    Rao, M.S.M.; Gupta, G.D.; Eisinger, F.L.

    1988-06-01

    As part of the overall EPRI program to develop a mechanistic model for tube fretting and wear prediction, Foster Wheeler Development Corporation undertook the responsibility of developing analytical models to predict structural response and wear in a multispan tube. The project objective was to develop the analytical capability to simulate the time-dependent motion of a multispan steam generator tube in the presence of the clearance gaps at each tube baffle or support. The models developed were to simulate nonlinear tube-to-tube support interaction by determining the impact force, the sliding distance, and the resultant tube wear. Other objectives of the project included: validate the models by comparing the analytical results with the EPRI tests done at Combustion Engineering (C-E) on single multispan tubes; test the models for simulating the U-bend region of the steam generator tube, including the antivibration bars; and develop simplified methods to treat the nonlinear dynamic problem of a multispan tube so that computing costs could be minimized. 15 refs., 53 figs., 27 tabs

  13. Systematic Review of Soft Tissue Alterations and Esthetic Outcomes Following Immediate Implant Placement and Restoration of Single Implants in the Anterior Maxilla.

    Science.gov (United States)

    Khzam, Nabil; Arora, Himanshu; Kim, Paul; Fisher, Anthony; Mattheos, Nikos; Ivanovski, Saso

    2015-12-01

    The aim of this review is to assess the outcome of single-tooth immediate implant placement and restoration (IPR) in the maxillary anterior region, with a particular emphasis on soft tissue and esthetic outcomes. An electronic search in Medline, EBSCOhost, and Ovid (PubMed) was performed to identify studies that reported on soft tissue outcomes following immediate placement and restoration of implants in the maxillary esthetic region with a mean follow-up of ≥1 year. Nineteen studies on single implants inserted immediately into fresh extraction sockets and provisionally restored in the maxillary esthetic region were included. Soft tissue changes were found to be acceptable, with most studies reporting mean gingival recession of 0.27 ± 0.38 mm and mean papillary height loss of 0.23 ± 0.27 mm after follow-up of ≥1 year. Advanced buccal recession (>1 mm) occurred in 11% of cases. Long-term follow-up studies (>2 years) reported that the interdental papillae, in particular, showed a tendency to rebound over time. The few studies that reported on patient-centered outcomes showed a high level of patient satisfaction with the outcomes of IPR treatment. The IPR protocol resulted in generally acceptable soft tissue and esthetic outcomes, with suboptimal results reported in ≈11% of low-risk cases. Factors such as preoperative tissue biotype or use of a flap or connective tissue graft did not significantly influence soft tissue and esthetic outcomes. Long-term prospective controlled clinical trials are necessary to identify factors that may influence the esthetic outcomes associated with IPR.

  14. Esthetic and cosmetic dermatology.

    Science.gov (United States)

    Wollina, Uwe; Goldman, Alberto; Berger, Uwe; Abdel-Naser, Mohammed Badawy

    2008-01-01

    The field of esthetic and cosmetic dermatology has gained remarkable interest all over the world. The major advantage of recent years is the high scientific levels of the most significant new developments in techniques and pharmacotherapy and other nonsurgical approaches. The present paper reviews selected fields of interest under this view. Sexual hormones are involved in the aging process of men and women. Skin function, in particular the epidermal barrier, is affected by a loss of endocrine activity. Hormone replacement therapy has only recently been introduced in treatment of aging males. This is an area of gender-medicine in dermatology with a strong well-aging attempt. Botulinum toxin therapy for hyperfunctional lines has become not only well-established but evidence-based medicine on its highest level. Recent advantages were gained in objective evaluation and monitoring the effect. Digital imaging techniques with various facets have been introduced to assess the achievements of treatment in the most objective way. This may become an example for other techniques as peeling, laser therapy, or radiofrequency in esthetic and cosmetic dermatology. Botulinum toxin has become a valuable tool for brow lifts. Details of the technique are discussed. Cellulite is a strongly female gender-related condition. During the past decades numerous treatments had been recommended but only recently a more critical scientific approach led to improvements in therapy of this common and disfiguring condition. Three major approaches are developed: (a) skin loosing with techniques such as subcision, (b) skin tightening with radiofrequency and other approaches, and (c) improving circulation in blood and lymphatic microvasculature using both physical treatments and pharmacotherapy. The last two chapters are devoted to body sculpturing by lipotransfer and lipolysis. Lipotransfer for facial or body sculpturing has a history of about 100 years. Nevertheless, recently the role of adult stem

  15. Wear-Time Compliance with a Dual-Accelerometer System for Capturing 24-h Behavioural Profiles in Children and Adults

    Directory of Open Access Journals (Sweden)

    Scott Duncan

    2018-06-01

    Full Text Available To advance the field of time-use epidemiology, a tool capable of monitoring 24 h movement behaviours including sleep, physical activity, and sedentary behaviour is needed. This study explores compliance with a novel dual-accelerometer system for capturing 24 h movement patterns in two free-living samples of children and adults. A total of 103 children aged 8 years and 83 adults aged 20-60 years were recruited. Using a combination of medical dressing and purpose-built foam pouches, participants were fitted with two Axivity AX3 accelerometers—one to the thigh and the other to the lower back—for seven 24 h periods. AX3 accelerometers contain an inbuilt skin temperature sensor that facilitates wear time estimation. The median (IQR wear time in children was 160 (67 h and 165 (79 h (out of a maximum of 168 h for back and thigh placement, respectively. Wear time was significantly higher and less variable in adults, with a median (IQR for back and thigh placement of 168 (1 and 168 (0 h. A greater proportion of adults (71.6% achieved the maximum number of complete days when compared to children (41.7%. We conclude that a dual-accelerometer protocol using skin attachment methods holds considerable promise for monitoring 24-h movement behaviours in both children and adults.

  16. Design improvement for fretting-wear reduction of HANARO fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yeong Garp; Chae, H. T.; Ryu, J. S.; Kim, H. R

    2000-06-01

    In the course of the visual inspection of the fuel assemblies un-loaded from the reactor core in December 1996, it was observed that many of fuel assemblies had mechanical damages on some components. The major damage was the freting-wear on spacer plates and endplates due to the flow induced vibration of the fuel assembly in the flow tube. Since the reactor is activated and the system modification for complete removal of the driving factors of the vibration of fuel assemblies is practically very difficult, the focus has been on the design change of the fuel assemblies. Consequently, various design changes were proposed to strengthen the wear resistance of the components based on the evaluation of the visual inspection results. The validity of the proposals was verified through the performance tests for the modified components, and the vibration test and endurance test for the fuel assemblies using the single-channel test rig(SCTR) in AECL.The subsequent design changes were additionally proposed based on the visual inspections for the fuel assemblies that had been fabricated according to the first design change and loaded in the core. As the effects of the first design change, the fretting-wear of spacer plates was remarkably reduced and the period until fretting-wear damage was extended by 60% for the first modified 36-rod fuel assembly. It is too early to say the endurance life time for the first modified 18-rod fuel assembly because of insufficient statistical data of only two bundles damaged, but the fretting-wear at the bottom endplate slot was reduced to about 50%. The second modified fuel assemblies, that were not loaded into the core yet, are expected to meet the design requirements for the core residence time due to strengthening the weak parts from the fretting-wear point of view. This report describes design changes and tests for fuel assemblies of HANARO to reduce the fretting-wear, and estimates the effects of design improvement quantitatively compared

  17. Design improvement for fretting-wear reduction of HANARO fuel assembly

    International Nuclear Information System (INIS)

    Cho, Yeong Garp; Chae, H. T.; Ryu, J. S.; Kim, H. R.

    2000-06-01

    In the course of the visual inspection of the fuel assemblies un-loaded from the reactor core in December 1996, it was observed that many of fuel assemblies had mechanical damages on some components. The major damage was the freting-wear on spacer plates and endplates due to the flow induced vibration of the fuel assembly in the flow tube. Since the reactor is activated and the system modification for complete removal of the driving factors of the vibration of fuel assemblies is practically very difficult, the focus has been on the design change of the fuel assemblies. Consequently, various design changes were proposed to strengthen the wear resistance of the components based on the evaluation of the visual inspection results. The validity of the proposals was verified through the performance tests for the modified components, and the vibration test and endurance test for the fuel assemblies using the single-channel test rig(SCTR) in AECL.The subsequent design changes were additionally proposed based on the visual inspections for the fuel assemblies that had been fabricated according to the first design change and loaded in the core. As the effects of the first design change, the fretting-wear of spacer plates was remarkably reduced and the period until fretting-wear damage was extended by 60% for the first modified 36-rod fuel assembly. It is too early to say the endurance life time for the first modified 18-rod fuel assembly because of insufficient statistical data of only two bundles damaged, but the fretting-wear at the bottom endplate slot was reduced to about 50%. The second modified fuel assemblies, that were not loaded into the core yet, are expected to meet the design requirements for the core residence time due to strengthening the weak parts from the fretting-wear point of view. This report describes design changes and tests for fuel assemblies of HANARO to reduce the fretting-wear, and estimates the effects of design improvement quantitatively compared

  18. The role of complete overdentures in esthetic rehabilitation of the adolescent oligodontia patient. A case report.

    Science.gov (United States)

    Thalji, Ghadeer N; Cooper, Lyndon F

    2010-08-01

    Dental agenesis is a common developmental anomaly among human populations. It presents with varying degrees of severity. Oligodontia present in the permanent dentition may have significant esthetic, psychosocial, as well as functional implications. A case of oligodontia in an adolescent patient treated with conventional overdentures is presented in this article. A thorough medical and dental history were taken. Comprehensive clinical and radiographic examinations were made. Diagnostic casts were mounted. The prosthetic denture teeth were set and followed by esthetic and phonetic evaluation. Following approval by the patient, the overdentures were processed in heat cure resin using the conventional techniques. Good esthetic results were achieved. Patient was satisfied with the final prostheses. Simple prosthodontic solutions can be utilized to aid patients with dental agenesis. These have great implications for the patient's self image. Oligodontias are common. The literature frequently addresses esthetic rehabilitation using fixed prostheses and dental implants. This case report illustrates the value of removable prosthodontic procedures as one approach to fulfilling the requirements of esthetic rehabilitation of a young oligodontia patient.

  19. Esthetic management of anterior dental anomalies: A clinical case.

    Science.gov (United States)

    Chafaie, Amir

    2016-09-01

    Many types of dental abnormality can be observed in the anterior sectors, where they can cause genuine esthetic problems for our patients. While conventional prosthetic treatments offer the best solutions in terms of esthetic result and durability, they involve the sacrifice of significant quantities of mineralized dental material and cannot be undertaken before the periodontal tissues are mature. Other less invasive alternatives should be envisaged as transitional, or sometimes even permanent, solutions for the management of these anomalies in children and adolescents. This article discusses these options and presents a clinical case where composite resin veneers and microabrasion of the enamel were used to treat dental agenesis and enamel dysplasia. Copyright © 2016 CEO. Published by Elsevier Masson SAS. All rights reserved.

  20. Modified hyrax splint for rapid maxillary expansion in esthetically concerned patients

    Directory of Open Access Journals (Sweden)

    Sarabjeet Singh Sandhu

    2015-01-01

    Full Text Available The orthodontic treatment of Class III malocclusion with a maxillary deficiency is often treated with maxillary protraction either with or without maxillary expansion. The routine procedure for rapid maxillary expansion includes banding on first premolars/first deciduous molars and the permanent first molars. However in some patients who are esthetically very conscious, banding of the first premolar would not be a good esthetic option. So for such circumstances we have designed a modified hyrax splint, which does not need the first premolars to be banded.

  1. Functional and Esthetic Comparison of Metal-Ceramic and All-Ceramic Posterior Three-Unit Fixed Dental Prostheses.

    Science.gov (United States)

    Nicolaisen, Maj H; Bahrami, Golnosh; Schropp, Lars; Isidor, Flemming

    2016-01-01

    The aim of this study was to assess functional and esthetic satisfaction plus evaluate changes in oral health-related quality of life (OHRQoL) using the Oral Health Impact Profile (OHIP-14) after insertion of a metal-ceramic (MC-FDP) or a veneered zirconia all-ceramic (AC-FDP) posterior three-unit fixed dental prosthesis (FDP). Additionally, patients' and professionals' esthetic evaluations were compared. A convenience sample of 34 patients was randomized to receive a MC-FDP (n = 17) or an AC-FDP (n = 17). Patients were assessed using the OHIP-14 and also answered a questionnaire regarding satisfaction with function and esthetics using visual analog scales (VAS) before treatment and after 2 weeks, after 3 months, and after 1, 2, and 3 years. A fully dentate control group (n = 20) was also assessed using the OHIP-14. The operator and another observer evaluated the esthetics of the FDPs using VAS. The patients assessed the two FDP types similarly for all parameters. In contrast, there was a statistically significant difference in OHIP-14 results between the treated patients and the control group before treatment. After treatment, a statistically significant improvement in OHIP-14 was observed at all examinations. Patients were highly satisfied with the function and esthetics of the FDPs. The overall satisfaction with esthetics was statistically significantly higher among the patients than among the professionals at three out of five examinations. The patients experienced improved OHRQoL and increased satisfaction with function and esthetics after receiving a posterior three-unit FDP. No important differences were observed between the two types of FDPs when evaluated by the patient or the professionals.

  2. Predicting railway wheel wear under uncertainty of wear coefficient, using universal kriging

    International Nuclear Information System (INIS)

    Cremona, Marzia A.; Liu, Binbin; Hu, Yang; Bruni, Stefano; Lewis, Roger

    2016-01-01

    Railway wheel wear prediction is essential for reliability and optimal maintenance strategies of railway systems. Indeed, an accurate wear prediction can have both economic and safety implications. In this paper we propose a novel methodology, based on Archard's equation and a local contact model, to forecast the volume of material worn and the corresponding wheel remaining useful life (RUL). A universal kriging estimate of the wear coefficient is embedded in our method. Exploiting the dependence of wear coefficient measurements with similar contact pressure and sliding speed, we construct a continuous wear coefficient map that proves to be more informative than the ones currently available in the literature. Moreover, this approach leads to an uncertainty analysis on the wear coefficient. As a consequence, we are able to construct wear prediction intervals that provide reasonable guidelines in practice. - Highlights: • Wear prediction is of outmost importance for reliability of railway systems. • Wear coefficient is essential in prediction through Archard's equation. • A novel methodology is developed to predict wear and RUL. • Universal kriging is used for wear coefficient and uncertainty estimation. • A simulation study and a real case application are provided.

  3. Cephalometric norms and esthetic profile preference for the Japanese: a systematic review.

    Science.gov (United States)

    Bronfman, Caroline Nemetz; Janson, Guilherme; Pinzan, Arnaldo; Rocha, Thais Lima

    2015-01-01

    To determine the cephalometric parameters and esthetic preferences of a pleasant face for the Japanese population. For the present study, the following databases were accessed: PubMed, Embase, Scopus and Web of Science. Initial inclusion criteria comprised studies written in English and quoting cephalometric norms and/or facial attractiveness in Japanese adults. No time period of publication was determined. The quality features evaluated were sample description, variables analyzed and how cephalometric standards or facial profile were evaluated. Initially, 60 articles were retrieved. From the selected studies, 13 abstracts met the initial inclusion criteria. They were divided into two groups; seven articles were included in Group I and six articles in Group II, according to the criteria of evaluation: cephalometric or facial analyses. Japanese are characterized by having a less convex skeletal profile, bilabial protrusion, less prominent nose, more retruded chin and protruded mandibular incisor. Despite living in a society with homogeneous patterns, they seem to get an esthetic preference for white-like features. Therefore, in addition to ethnic normative values, patient's preferences to establish individual treatment plans should always be considered.

  4. The importance of being 'well-placed': the influence of context on perceived typicality and esthetic appraisal of product appearance.

    Science.gov (United States)

    Blijlevens, Janneke; Gemser, Gerda; Mugge, Ruth

    2012-01-01

    Earlier findings have suggested that esthetic appraisal of product appearances is influenced by perceived typicality. However, prior empirical research on typicality and esthetic appraisal of product appearances has not explicitly taken context effects into account. In this paper, we investigate how a specific context influences perceived typicality and thus the esthetic appraisal of product appearances by manipulating the degree of typicality of a product's appearance and its context. The findings of two studies demonstrate that the perceived typicality of a product appearance and consequently its esthetic appraisal vary depending on the typicality of the context in which the product is presented. Specifically, contrast effects occur for product appearances that are perceived as typical. Typical product appearances are perceived as more typical and are more esthetically appealing when presented in an atypical context compared to when presented in a typical context. No differences in perceived typicality and esthetic appraisal were found for product appearances that are perceived as atypical. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. A review on real time physical measurement techniques and their attempt to predict wear-out status of IGBT

    DEFF Research Database (Denmark)

    Ghimire, Pramod; Beczkowski, Szymon; Munk-Nielsen, Stig

    2013-01-01

    Insulated Gate Bipolar Transistors (IGBTs) are key component in power converters. Reliability of power converters depend on wear-out process of power modules. A physical parameter such as the on-state collector-emitter voltage (Vce) shows the status of degradation of the IGBT after a certain cycles...... of difficulties in the measurement, the offline and online Vce measurement topologies are implemented to study the reliability of the power converters. This paper presents a review in wear-out prediction methods of IGBT power modules and freewheeling diodes based on the real time Vce measurement. The measurement...

  6. Soft tissue development in the esthetic zone : a clinical trial on abutment geometry and it's effect on muco-gingival esthetics

    NARCIS (Netherlands)

    Patil, Ratnadeep Chandrakant

    2016-01-01

    Dental implants have been offered as favorable options the world over to replace missing teeth and with increasing human life expectancy the need for long-term maintenance of implant- teeth for esthetics and function has become ever so important, especially the soft tissue (gums)formation around

  7. Abdominoplasty for Ladd's procedure: optimizing access and esthetics

    African Journals Online (AJOL)

    Abdominoplasty for Ladd's procedure: optimizing access and esthetics. Rachel Aliotta, Neilendu Kundu, Anthony Stallion, Christi Cavaliere. Abstract. Rotational anomalies occur when there is an abnormal arrest of rotation in the embryonic gut during development. The characteristic population affected is considered to be ...

  8. Development and validation of a new condition-specific instrument for evaluation of smile esthetics-related quality of life.

    Science.gov (United States)

    Saltovic, Ema; Lajnert, Vlatka; Saltovic, Sabina; Kovacevic Pavicic, Daniela; Pavlic, Andrej; Spalj, Stjepan

    2018-03-01

    Orofacial esthetics raises psychosocial issues. The purpose was to create and validate new short instrument for psychosocial impacts of altered smile esthetics. A team of an orthodontist, two prosthodontists, psychologist, and a dental student generated items that could draw up specific hypothetical psychosocial dimensions (69 items initially, 39 in final analysis). The sample consisted of 261 Caucasian subjects attending local high schools and university (26% male) aged 14 to 28 years that have self-administrated the designed questionnaire. Factorial analysis, Cronbach's alpha, Pearson correlation, paired samples t-test and analysis of variance were used for analyses of internal consistency, construct validity, responsiveness, and test-retest. Three dimensions of psychosocial impacts of altered smile esthetics were identified: dental self-consciousness, dental self-confidence and social contacts that can be best fitted by 12 items, 4 items in each dimension. Internal consistency was good (α in range 0.85-0.89). Good stability in test-retest was confirmed. In responsiveness testing, tooth whitening induced increase in dental self-confidence (P = 0.002), but no significant changes in other dimensions. The new instrument, Smile Esthetics-Related Quality of Life (SERQoL), is short and has proven to be a good indicator of psychosocial dimensions related to perception of smile esthetics. Smile Esthetics-Related Quality of Life questionnaire might have practical validity when applied in esthetic dental clinical procedures. © 2017 Wiley Periodicals, Inc.

  9. Occlusal wear of provisional implant-supported restorations.

    Science.gov (United States)

    Santing, Hendrik J; Kleverlaan, Cornelis J; Werner, Arie; Feilzer, Albert J; Raghoebar, Gerry M; Meijer, Henny J A

    2015-02-01

    Implant-supported provisional restorations should be resistant to occlusal wear. The purpose of this laboratory study was to evaluate three-body wear of three indirect laboratory composite resins, five chair side bis-acryl resin-based materials, and two chair side methacrylate-based materials used to fabricate provisional implant-supported restorations. The materials were handled and cured according to the manufacturers' instructions. The three-body wear was measured 1 day, 3 days, 7 days, 4 weeks, and 8 weeks after curing using the ACTA wear device. Wear rate decreased significantly after 8 weeks compared with the first day for all tested materials, except for Estenia C&B. The three-body wear of two indirect laboratory composite resins, that is, Estenia C&B and Solidex, was significantly less compared with all other tested materials used for fabricating provisional implant-supported restorations. Of the chair side materials, the wear rate of Protemp Crown Paste was significantly less compared with the others materials used to fabricate chair side provisional implant-supported restorations. The methacrylate-based materials, Temdent Classic and Trim, showed extreme high wear rates. Based on the results of this laboratory study on long-term wear, the use of indirect composite resin is preferred over chair side methacrylate-based materials when the provisional implant-supported restoration has to be in service for a long period of time. Of the investigated materials, only Estenia C&B and Solidex showed wear rate comparable with posterior resin composites. © 2013 Wiley Periodicals, Inc.

  10. Immediate provisionalization of immediate implants in the esthetic zone: a prospective case series evaluating implant survival, esthetics, and bone maintenance.

    Science.gov (United States)

    Levin, Barry P; Wilk, Brian L

    2013-05-01

    This prospective study evaluates immediately placed and immediately provisionalized implants in the esthetic zone. All implants were TiO2-blasted, fluoride-modified, grade 4 titanium, with a coronal microthread design. Bone grafting and guided bone regeneration (GBR) was performed at all sites, and screw-retained temporary restorations were delivered on the day of surgery. All of the provisional crown(s) were out of occlusal function and remained in place for at least 8 weeks prior to initiation of definitive restorative therapy. Bone maintenance (BM) was considered successful if radiographs demonstrated proximal bone levels even or coronal to the implant platform. Of the 29 implants placed, 25 (86 percent) achieved bone maintenance at least 12 months post-loading with the final restorations. This study was considered successful, with 100 percent implant survival after at least 1 year loading of the final restoration, and 100 percent of patients were satisfied with the esthetics of their implant treatment.

  11. Assessment of wear dependence parameters in complex model of cutting tool wear

    Science.gov (United States)

    Antsev, A. V.; Pasko, N. I.; Antseva, N. V.

    2018-03-01

    This paper addresses wear dependence of the generic efficient life period of cutting tools taken as an aggregate of the law of tool wear rate distribution and dependence of parameters of this law's on the cutting mode, factoring in the random factor as exemplified by the complex model of wear. The complex model of wear takes into account the variance of cutting properties within one batch of tools, variance in machinability within one batch of workpieces, and the stochastic nature of the wear process itself. A technique of assessment of wear dependence parameters in a complex model of cutting tool wear is provided. The technique is supported by a numerical example.

  12. Esthetic, occlusal, and periodontal rehabilitation of anterior teeth with minimum thickness porcelain laminate veneers.

    Science.gov (United States)

    da Cunha, Leonardo Fernandes; Pedroche, Lorena Oliveira; Gonzaga, Carla Castiglia; Furuse, Adilson Yoshio

    2014-12-01

    Ceramic veneers of minimum thickness provide satisfactory esthetic outcomes while preserving the dental structure. Dental ceramics can both improve the esthetic appearance and reestablish the strength and function of teeth. In worn anterior teeth, functional surfaces, for example, anterior and lateral guidance, can be restored effectively. The characteristics of dental ceramics, such as color stability and mechanical and optical properties, make this material a good choice for indirect restorations, especially when optimum function and esthetics are required. This clinical report presents an occlusal, periodontal, and restorative solution with minimum thickness glass ceramic veneers for worn anterior teeth with multiple diastemas. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  13. Esthetic considerations in management of shortleaf pine

    Science.gov (United States)

    Robert H. Stignani

    1986-01-01

    Application of esthetic concerns in the management of shortleaf pine or any species should be predicated on a systematic approach. Many mitigation techniques are available, but those selected will need to be carefully tailored to the specific situation and to the unique characteristics of plant communities and landforms involved. Some additional costs should be...

  14. Epidemiology of Shoe Wearing Patterns Over Time in Older Women: Associations With Foot Pain and Hallux Valgus.

    Science.gov (United States)

    Menz, Hylton B; Roddy, Edward; Marshall, Michelle; Thomas, Martin J; Rathod, Trishna; Peat, George M; Croft, Peter R

    2016-12-01

    Foot problems are prevalent in older women and are thought to be associated with footwear. This study examined women's shoe wearing patterns over time and evaluated associations between footwear characteristics and foot pain and hallux valgus. Women aged 50-89 years (n = 2,627) completed a survey that included drawings of four toe-box shapes and four heel heights. For each life decade, participants indicated which footwear style they wore most of the time. Foot pain in the past 12 months and hallux valgus were documented by self-report. Logistic regression examined associations between heel height, toe-box shape, foot pain and hallux valgus. Wearing shoes with a high heel and very narrow toe box between the ages of 20 and 29 was common, but decreased to less than 10% by the age of 40. Compared with women who had worn shoes with a very wide toe box, the likelihood of hallux valgus increased in those who had worn shoes with a wide (odds ratio [OR] 1.96, 95% CI 1.03-3.71), narrow (2.39, 1.29-4.42) and very narrow (2.70, 1.46-5.00) toe box between the ages of 20 and 29 and those who wore shoes with a very narrow toe box (1.93, 1.10-3.39) between the ages of 30 and 39. Women wear shoes with a lower heel and broader toe box as they age. Wearing constrictive footwear between the ages of 20 and 39 may be critical for developing hallux valgus in later life. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America.

  15. A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

  16. A Comparative Study on the Formation Mechanism of Wear Scars during the Partial and Full Scale Fretting Wear Tests of Spacer Grids

    International Nuclear Information System (INIS)

    Lee, Young Ho; Shin, Chang Hwan; Oh, Dong Seok; Kang, Heung Seok

    2012-01-01

    Fretting wear studies for evaluating the contact damages of nuclear fuel rods have been focused on the contact shape, rod motion, contact condition, environment, etc.. However, fretting wear mechanism was dramatically changed with slight variation of test variables such as test environments and contact shapes. For example, in an unlubricated condition, effects of wear debris and/or its layer on the fretting wear mechanism showed that the formation of a well-developed layer on the contact surfaces has a beneficial effect for decreasing a friction coefficient. Otherwise, a severe wear was happened due to a third body abrasion. In addition, in water lubrication condition, some of wear debris was remained on worn surface of fuel rod specimens at both sliding and impacting loading conditions. So, it is apparent that a wear rate of fuel rod specimen was easily accelerated by the third-body abrasion. This is because the restrained agglomeration behavior between generated wear particles results in rapid removal of wear debris and its layer. In case of contact shape effects, previous studies show that wear debris are easily trapped between contact surfaces and its debris layer was well developed in a localized area especially in a concave spring rather than a convex spring shape. Consequently, localized wear was happened at both ends of a concave spring and center region of a convex spring. So, it is useful for determining the fretting wear resistance of spacer gird spring and dimple by using part unit in the various lubricated conditions. It is well known that the fretting wear phenomenon of nuclear fuel rod is originated from a flow-induced vibration (FIV) due to the rapid primary coolant. This means that both rod vibration and debris removal behavior were affected by flow fields around the contact regions between fuel rod and spring/dimple. However, all most of the fretting tests were performed by simulating rod vibrating motions such as axial vibration, conservative rod

  17. Friction and wear methodologies for design and control

    CERN Document Server

    Straffelini, Giovanni

    2015-01-01

    This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professi...

  18. Treatment Outcome and Patient Satisfaction with Two Adjacent Implant-Supported Restorations in the Esthetic Zone

    NARCIS (Netherlands)

    Tymstra, Nynke; Meijer, Henny J. A.; Stellingsma, Kees; Raghoebar, Gerry M.; Vissink, Arjan

    2010-01-01

    The purpose of this study was to evaluate the clinical and radiographic parameters as well as the esthetic outcome of two adjacent implant-supported restorations and the surrounding peri-implant mucosa in the maxillary esthetic zone. Ten patients were treated with two adjacent implants in the

  19. Part-Time Faculty Satisfaction at Two-Year Public Postsecondary Institutions: A Comparison of Involuntary Part-Time, Voluntary Part-Time, and Full-Time Faculty

    Science.gov (United States)

    Kinchen, Nancy Huval

    2010-01-01

    Part-time faculty members represent the majority of faculty at public two-year postsecondary institutions. Utilizing part-time faculty enables two-year institutions to control their instructional costs and maintain scheduling flexibility. However, part-time faculty are diverse in regards to their employment preference, some prefer part-time…

  20. Factors determining esthetic outcome after breast cancer conservative treatment

    DEFF Research Database (Denmark)

    Cardoso, Maria J; Cardoso, Jaime; Santos, Ana C

    2007-01-01

    with lower body mass index (BMI) and premenopausal status obtained better cosmetic results. In the group of tumor- and treatment-related factors, larger removed specimens, clearly visible scars, the use of chemotherapy and longer follow-up period were associated with less satisfactory results......The aim of this study was to evaluate the factors that determine esthetic outcome after breast cancer conservative treatment, based on a consensual classification obtained with an international consensus panel. Photographs were taken from 120 women submitted to conservative unilateral breast cancer...... surgery (with or without axillary surgery) and radiotherapy. The images were sent to a panel of observers from 13 different countries and consensus on the classification of esthetic result (recorded as excellent, good, fair or poor) was obtained in 113 cases by means of a Delphi method. For each patient...

  1. Esthetic Rehabilitation of Primary Anterior Teeth using Temporization Material: A Novel Approach

    Science.gov (United States)

    Pandit, IK; Gupta, Monika; Nagpal, Jyoti

    2017-01-01

    Pediatric dentists should always aim for esthetic and functional rehabilitation of decayed/traumatized primary teeth. The most common method for restoring such teeth involves the use of “strip crowns” with composites, while the recent trend is toward using other extracoronal restorations including preve-neered stainless steel crowns and zirconia crowns. All these restorative options have shown good success rates, but also have some limitations. This case series depicts novel clinical technique of using a temporization material for full-coronal restoration(s) in primary anterior teeth. This included the chair-side custom fabrication of full-coronal restoration using temporization material, which has resulted in good immediate esthetics and might be a cost-effective alternative for restoring primary anterior teeth in future. How to cite this article Gugnani N, Pandit IK, Gupta M, Nagpal J. Esthetic Rehabilitation of Primary Anterior Teeth using Temporization Material: A Novel Approach. Int J Clin Pediatr Dent 2017;10(1):111-114. PMID:28377667

  2. Hardness and microstructure analysis of damaged gear caused by adhesive wear

    Science.gov (United States)

    Mahendra, Rizky Budi; Nugroho, Sri; Ismail, Rifky

    2018-03-01

    This study was a result from research on repairing project of damaged elevator gear box. The objective of this research is to analyze the failure part on elevator gearbox at flourmill factory. The equipment was damaged after one year installed and running on factory. Severe wear was occurred on high speed helical gear. These helical gear was one of main part of elevator gearbox in flour mill manufacture. Visually, plastic deformation didn't occurred and not visible on the failure helical gear shaft. Some test would be performed to check the chemical composition, microstructure and hardness of failure helical gear. The material of failure helical gear shaft was a medium carbon steel alloy. The microstructure was showed a martensitic phase formed on the surface to the center area of gear shaft. Otherwise, the depth of hardness layer slight formed on surface and lack depth of hardness layer was a main trigger of severe wear. It was not enough to resist wear due to friction caused by rolling and sliding on surface between high speed gear and low speed gear. Enhancement of hardness layer on surface and depth of hardness layer will make the component has more long life time. Furthermore, to perform next research is needed to analyze the reliability of enhanced hardness on layer and depth of hardness layer on helical gear shaft.

  3. Tibiofemoral wear in standard and non-standard squat: implication for total knee arthroplasty.

    Science.gov (United States)

    Fekete, Gusztáv; Sun, Dong; Gu, Yaodong; Neis, Patric Daniel; Ferreira, Ney Francisco; Innocenti, Bernardo; Csizmadia, Béla M

    2017-01-01

    Due to the more resilient biomaterials, problems related to wear in total knee replacements (TKRs) have decreased but not disappeared. In the design-related factors, wear is still the second most important mechanical factor that limits the lifetime of TKRs and it is also highly influenced by the local kinematics of the knee. During wear experiments, constant load and slide-roll ratio is frequently applied in tribo-tests beside other important parameters. Nevertheless, numerous studies demonstrated that constant slide-roll ratio is not accurate approach if TKR wear is modelled, while instead of a constant load, a flexion-angle dependent tibiofemoral force should be involved into the wear model to obtain realistic results. A new analytical wear model, based upon Archard's law, is introduced, which can determine the effect of the tibiofemoral force and the varying slide-roll on wear between the tibiofemoral connection under standard and non-standard squat movement. The calculated total wear with constant slide-roll during standard squat was 5.5 times higher compared to the reference value, while if total wear includes varying slide-roll during standard squat, the calculated wear was approximately 6.25 times higher. With regard to non-standard squat, total wear with constant slide-roll during standard squat was 4.16 times higher than the reference value. If total wear included varying slide-roll, the calculated wear was approximately 4.75 times higher. It was demonstrated that the augmented force parameter solely caused 65% higher wear volume while the slide-roll ratio itself increased wear volume by 15% higher compared to the reference value. These results state that the force component has the major effect on wear propagation while non-standard squat should be proposed for TKR patients as rehabilitation exercise.

  4. Comparison of Dental Esthetic Perceptions of Young Adolescents and Their Parents

    Science.gov (United States)

    Kavand, Golnaz; Broffitt, Barbara; Levy, Steven M.; Warren, John J.

    2012-01-01

    Objective To compare dental esthetic perceptions of adolescents at age 13 with those of parents and to assess associations with dental fluorosis. Methods As part of the Iowa Fluoride Study, 550 adolescents aged 13 underwent dental examinations for fluorosis on maxillary anterior teeth using the Fluorosis Risk Index. Adolescents and parents completed questionnaires concerning satisfaction with the adolescents’ dental appearance. McNemar and Bowker tests of symmetry were used for comparisons of esthetics ratings between parents and adolescents. Comparison of satisfaction between fluorosis and non-fluorosis subjects was made using Cochran-Armitage Trend and Fisher’s Exact tests. Results Excluding subjects with orthodontic treatment, 376 adolescents were included and 26% of them had definitive fluorosis, mostly at a mild level. Fifteen percent of adolescents were dissatisfied with dental appearance, and concerns were mainly about the tooth color (45%) and alignment (35%). Adolescents were less satisfied with overall dental appearance (P0.05). Parents of subjects with fluorosis were more dissatisfied with dental appearance (P=0.014) and color (P<0.001) than other parents. The number of maxillary anterior zones exhibiting fluorosis was negatively associated with both adolescent (P=0.03) and parent (P=0.002) satisfaction. Conclusion Adolescents generally had less satisfaction with dental appearance and color and they were more concerned with tooth shape than parents. For both parents and adolescents, decreased satisfaction was associated with the number of zones with definitive fluorosis. PMID:22364682

  5. Systemic embolism produced by subcutaneous injections of liquid silicone for esthetic purposes

    International Nuclear Information System (INIS)

    Falconi, Guillermo

    2003-01-01

    Even though its use is not recommended, liquid silicone is a substance that has been used illegally for esthetic purposes for a long time. A case report is presented in which a young woman was injected subcutaneously, by an uncertified practitioner, industrial fluid silicone and subsequently developed a case of systemic embolism with pulmonary, skin and ocular complications. This article explains the physiopathology and the different manifestations of systemic embolism produced by fluid silicone. TAC was used. (The author)

  6. A wavelet filtering method for cumulative gamma spectroscopy used in wear measurements

    International Nuclear Information System (INIS)

    Bianchi, Davide; Lenauer, Claudia; Betz, Gerhard; Vernes, András

    2017-01-01

    Continuous ultra-mild wear quantification using radioactive isotopes involves measuring very low amounts of activity in limited time intervals. This results in gamma spectra with poor signal-to-noise ratio and hence very scattered wear data, especially during running-in, where wear is intrinsically low. Therefore, advanced filtering methods reducing the wear data scattering and making the calculation of the main peak area more accurate are mandatory. An energy-time dependent threshold for wavelet detail coefficients based on Poisson statistics and using a combined Barwell law for the estimation of the average photon counting rate is then introduced. In this manner, it was shown that the accuracy of running-in wear quantification is enhanced. - Highlights: • Time-dependent Poisson statistics. • Wavelet-based filtering of cumulative gamma spectra. • Improvement of low wear analysis.

  7. Esthetic management of compromised ridge in the anterior maxilla, a modified prosthetic approach

    Directory of Open Access Journals (Sweden)

    R Lambodharan

    2017-01-01

    Full Text Available Replacing a missing tooth with an implant, especially in the esthetic zone has been increasing demand for the patient. Placing dental implants in the esthetic zone, especially in the compromised ridge with thin gingival thin biotype is considered to be the ultimate challenge for many dentists. This case report illustrates the implant placement in the traumatic anterior maxilla with thin gingival biotype (Class IV and a modified approach in prosthetic placement.

  8. Evaluation of smile esthetics by photographic assessment of the dento-labio-gingival complex

    OpenAIRE

    Mundoor Manjunath Dayakar; Anna Shipilova; M Rekha

    2015-01-01

    Context: The esthetics of a smile is determined by various factors including symmetry, anatomy and position of teeth, periodontal visibility, and musculoskeletal relationships. Aim: This study analyzed the dento-labio-gingival esthetic components of the smile, evaluating: (a) Amount of gingiva visible during natural smile and forced smile, (b) relationship between incisal edges of maxillary anterior teeth and upper border of lower lip, (c) deviation of dental midline from facial midline to ri...

  9. Radioactive wear tests of four cylinder liner materials

    International Nuclear Information System (INIS)

    Sylte, G.

    1976-01-01

    An investigation on the wear properties of various liner materials, financed by a research grant from NTNF (Royal Norwegian Council for Scientific and Industrial Research), is reported. The investigation was carried out by the Division of Internal Combustion Engines, Trondheim, Univ.,Norway, on a two-stroke, turbocharged, medium speed diesel engine (Wichmann 2ACAT, 280 by 420 mm). Thin pearlitic cast iron inserts of various compositions were pressed into the upper part of a specially machined cylinder liner. These inserts were activated in a nuclear reactor, and tracer techniques employed to measure the wear rate. Gas oil was used as a fuel throughout all tests. The insert technique employed, and the handling methods devised, were satisfactory. This part of the project must be characterised as being very successful. Originally, six different liner materials were specified, but due to misunderstandings duplications resulted in only four different materials finally being received at the laboratory. The engine tests disclosed that the wear rates of all four materials were low under laboratory conditions, and therefore difficult to measure accurately. Nevertheless, the wear properties of the inserts clearly fell into two distinct classes, which may be termed good and excellent. The relative values inside each group are, however, more uncertain due to the cumulative effects of errors, instrument drift, measurement statistics, etc. (Auth.)

  10. Modified Lip Repositioning with Esthetic Crown Lengthening: A Combined Approach to Treating Excessive Gingival Display.

    Science.gov (United States)

    Sánchez, Isis M; Gaud-Quintana, Sadja; Stern, Jacob K

    Lip repositioning surgery to address excessive gingival display induced by different etiologies has received major attention recently. Several techniques and variations have been reported, including myotomy or repositioning of the levator labii superioris muscle, Le Fort impaction, maxillary gingivectomies, botulinum toxin injections, and lip stabilization. This study reports a case of excessive gingival display treated by a modified combined approach. A 25-year-old woman with a 4- to 8-mm gingival display when smiling caused by a combination of short clinical crowns induced by an altered passive eruption and hypermobility of the upper lip underwent a staged esthetic crown-lengthening procedure followed by a modified lip repositioning technique. A description of the technique and a comparison with other modes of therapy is discussed. This modified approach for treating the hypermobile lip included a bilateral removal of a partial-thickness strip of mucosa from the maxillary buccal vestibule without severing the muscle, leaving the midline frenum intact and suturing the lip mucosa to the mucogingival line. The narrower vestibule and increased tooth length resulted in a symmetric and pleasing gingival display when smiling that remained stable over time. With proper diagnosis and sequence of therapy, modified lip repositioning surgery combined with esthetic crown lengthening can be used predictably to treat excessive gingival display and enhance smile esthetics.

  11. Immediate implant placement and provisionalization with simultaneous guided bone regeneration in the esthetic zone

    Directory of Open Access Journals (Sweden)

    Chih-Long Chen

    2011-03-01

    Full Text Available The procedure for immediate implant placement and provisionalization is time-saving, possibly with only one surgical intervention required, although allowing maximal preservation of peri-implant tissues. In this case, we extracted a fractured maxillary right central incisor of a 46-year-old woman with high esthetic expectations, and a transmucosal implant was immediately installed. Simultaneous guided bone regeneration was performed to correct the defects at the facial side of the socket and augment the alveolar ridge horizontally. Primary stability of the implant body and wound closure without tension were confirmed. Connection of a 15° angled abutment and fabrication of a provisional acrylic resin crown without occlusal contact were also completed in the same appointment. After intensive follow-up and soft-tissue molding for 6 months, the customized zirconia abutment and all-ceramic crown were definitively fabricated. During the 18-month follow-up period, the patient was satisfied with the esthetic and functional results.

  12. An expert system for the esthetic rating of bridges.

    Science.gov (United States)

    1990-01-01

    The expert system presented should facilitate the in-depth analysis of bridge esthetics and encourage high standards for the appearance of bridges. The procedure described systematically evaluates features of a target bridge in relation to a similar ...

  13. Influence of dental esthetics on social perceptions of adolescents judged by peers.

    Science.gov (United States)

    Henson, Scott T; Lindauer, Steven J; Gardner, W Graham; Shroff, Bhavna; Tufekci, Eser; Best, Al M

    2011-09-01

    The relationship between physical appearance and social attractiveness is well established in the literature. The purpose of this study was to determine whether dental esthetics influenced the perceptions of teens when judging a peer's athletic, social, leadership, and academic abilities. The frontal-face smiling photographs of 10 teenage volunteers were each altered to create 1 image with an ideal arrangement of teeth and 1 with a nonideal arrangement. Two parallel surveys were constructed with 1 photo displaying either an ideal or a nonideal smile image of each subject. If the ideal smile image appeared in 1 survey, then the nonideal smile appeared in the other. Two hundred twenty-one peer evaluators successfully rated the pictures in 1 of the surveys by indicating their perception of each subject's athletic, social, leadership, and academic abilities. The subjects' photographs with ideal smile esthetics were consistently rated higher on average than the same subjects' images with nonideal smile esthetics. The differences in ratings between ideal and nonideal smiles were significant for perceptions of athletic performance (P = 0.0141), popularity (P academic performance (P = 0.0548). On average, ratings for the ideal smiles in perceived athletic, social, and leadership skills were about 10% higher than those given for images with nonideal smiles. Based on these findings, it would be expected that orthodontic treatment resulting in improved smile esthetics can provide modest social benefits for adolescent patients. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  14. Transcultural Similarity in Personal Significance of Esthetic Interests

    Science.gov (United States)

    Haritos-Fatouros, M.; Child, Irvin L.

    1977-01-01

    Individual differences in esthetic preferences in visual art is correlated in Greece as in the U.S. with food and drink preferences suggestive of liking for oral change and with a pattern of self-characterization that indicates a liking for autonomy, variety, and intellectual and perceptual challenge. (Author/AM)

  15. Wear Performance of Bionic Dimpled-Shape Pistons of Mud Pump

    Directory of Open Access Journals (Sweden)

    Xuejing Cheng

    2017-01-01

    Full Text Available The piston is one of the parts that most easily become worn out and experience failure in mud pumps for well drilling. By imitating the body surface morphology of the dung beetle, this paper proposed a new type (BW-160 of mud pump piston that had a dimpled shape in the regular layout on the piston leather cup surface and carried out a performance test on the self-built test rig. Firstly, the influence of different dimple diameters on the service life of the piston was analyzed. Secondly, the analysis of the influence of the dimple central included angle on the service life of the piston under the same dimple area density was obtained. Thirdly, the wear of the new type of piston under the same wear time was analyzed. The experimental results indicated that the service life of the piston with dimples on the surface was longer than that of L-Standard pistons, and the maximum increase in the value of service life was 92.06%. Finally, the Workbench module of the software ANSYS was used to discuss the wear-resisting mechanism of the new type of piston.

  16. Implant prostheses for convertibility, stress control, esthetics, and hygiene.

    Science.gov (United States)

    Garfield, R E

    1988-07-01

    A method of connecting "fixed partial denture" prostheses to osseointegrated implant fixtures has been described. The advantages of this system of restoration for partially and fully edentulous mouths are that it is more effective in addressing the problems of (1) stress-control on abutments, (2) a back-up system for abutment failures, (3) esthetics, and (4) control of bacterial plaques around abutments. To accomplish this procedure, the application of convertible periodontal prosthesis techniques with modifications to some existing implant systems is undertaken. The disadvantages of this method seem insignificant when one considers the complexities and risks involved with the present array of implant prosthesis alternatives. Some patients and dentists might consider the necessity of the prosthesis being detachable as one disadvantage. In reality, the prosthesis can be used as a fixed restoration until the patient has fully adapted to the new proprioception and appearance. A large percentage of patients feel uncomfortable with the word "removable" because it immediately creates a perception of unsightly metallic clasp display, palatal coverage, tongue interference, and negative body image. The use of the term "detachable" coupled with the doctor's offer to perform this task for the patient "whenever necessary" will usually relieve the patient's anxiety and allow the treatment to proceed. Once neuromuscular and esthetic adaptation have occurred and the patient has accepted the prosthesis, daily detaching and home-care hygiene by the patient will follow without incident. Esthetic improvement is obvious (Fig. 3).

  17. In vitro biocompatibility of nickel-titanium esthetic orthodontic archwires.

    Science.gov (United States)

    Rongo, Roberto; Valletta, Rosa; Bucci, Rosaria; Rivieccio, Virginia; Galeotti, Angela; Michelotti, Ambrosina; D'Antò, Vincenzo

    2016-09-01

    To investigate the cytotoxicity of nickel-titanium (NiTi) esthetic orthodontic archwires with different surface coatings. Three fully coated, tooth-colored NiTi wires (BioCosmetic, Titanol Cosmetic, EverWhite), two ion-implanted wires (TMA Purple, Sentalloy High Aesthetic), five uncoated NiTi wires (BioStarter, BioTorque, Titanol Superelastic, Memory Wire Superelastic, and Sentalloy), one β-titanium wire (TMA), and one stainless steel wire (Stainless Steel) were considered for this study. The wire samples were placed at 37°C in airtight test tubes containing Dulbecco's Modified Eagle's Medium (0.1 mg/mL) for 1, 7, 14, and 30 days. The cell viability of human gingival fibroblasts (HGFs) cultured with this medium was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by a two-way analysis of variance (α  =  .05). The highest cytotoxic effect was reached on day 30 for all samples. The archwires exhibited a cytotoxicity on HGFs ranging from "none" to "slight," with the exception of the BioTorque, which resulted in moderate cytotoxicity on day 30. Significant differences were found between esthetic archwires and their uncoated pairs only for BioCosmetic (P  =  .001) and EverWhite (P < .001). Under the experimental conditions, all of the NiTi esthetic archwires resulted in slight cytotoxicity, as did the respective uncoated wires. For this reason their clinical use may be considered to have similar risks to the uncoated archwires.

  18. An experimental modeling and acoustic emission monitoring of abrasive wear in a steel/diabase pair

    Science.gov (United States)

    Korchuganov, M. A.; Filippov, A. V.; Tarasov, S. Yu.; Podgornyh, O. A.; Shamarin, N. N.; Filippova, E. O.

    2016-11-01

    The earthmoving of permafrost soil is a critical task for excavation of minerals and construction on new territories. Failure by abrasive wear is the main reason for excavation parts of earthmoving and soil cutting machines. Therefore investigation of this type of wear is a challenge for developing efficient and wear resistant working parts. This paper is focused on conducting tribological experiments with sliding the steel samples over the surface of diabase stone sample where abrasive wear conditions of soil cutting are modeled experimentally. The worn surfaces of all samples have been examined and transfer of metal and stone particles revealed. The acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. he acoustic emission (AE) signals have been recorded and related to the results of worn surface analysis. As shown the wear intensity correlates to that of acoustic emission. Both acoustic emission signal median frequency and energy are found to be sensitive to the wear mode.

  19. Development, validation and psychometric properties of the Arabic version of the Orofacial Esthetic Scale: OES-Ar.

    Science.gov (United States)

    Alhajj, Mohammed Nasser; Amran, Abdullah Ghalib; Halboub, Esam; Al-Basmi, Abdulghani Ali; Al-Ghabri, Fawaz Abdullah

    2017-07-01

    This study aimed at developing the Arabic version of the Orofacial Esthetic Scale (OES-Ar) and to investigate its psychometric properties among Arabic-speaking population with and without esthetic impairments. Translation and cross-cultural adaptation was done according to the standard guidelines. Internal consistency was assessed on 230 participants. For test-retest reliability, 50 subjects with natural teeth were recalled within a period of 2 weeks. Validity of the OES-Ar was tested by construct, convergent, and discriminant validity tests. Responsiveness to esthetic changes was assessed in 60 patients. The results showed excellent internal consistency with Cronbach's alpha value of 0.92 and inter-item correlation average value of 0.60. The ICC values ranged from 0.87 to 0.96 which indicated excellent agreement. Construct validity of the OES-Ar was confirmed to be one-factor structure (one-dimensional). For convergent validity, a significant correlation was found between OES summary score and overall impression of the orofacial esthetic as well as between OES summary score and the summary score of the three questions of the OHIP-49Ar related to esthetic. The discriminant validity test revealed significant differences between different study groups (Pesthetics in Arabic-speaking patients. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  20. A study on die wear model of warm and hot forgings

    Science.gov (United States)

    Kang, J. H.; Park, I. W.; Jae, J. S.; Kang, S. S.

    1998-05-01

    Factors influencing service lives of tools in warm and hot forging processes are wear, mechanical fatigue, plastic deformation and thermal fatigue, etc. Wear is the predominant factor for tool failure among these. To predict tool life by wear, Archard's model where hardness is considered as constant or function of temperature is generally applied. Usually hardness of die is a function of not only temperature but operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of temperature and time. In this study wear coefficients were measured for various temperatures and heat treatment for H13 tool steel. Also by experiment of reheating of die, die softening curves were obtained. From experimental results, relationships between tempering parameters and hardness were established to investigate effects of hardness decrease by the effect of temperatures and time. Finally modified Archard's wear model in which hardness is considered to be a function of main tempering curve was proposed. And finite element analyses were conducted by adopting suggested wear model. By comparisons of simulations and real profiles of worn die, proposed wear model was verified.

  1. The role of the posed smile in overall facial esthetics.

    Science.gov (United States)

    Havens, David C; McNamara, James A; Sigler, Lauren M; Baccetti, Tiziano

    2010-03-01

    To evaluate the role of the posed smile in overall facial esthetics, as determined by laypersons and orthodontists. Twenty orthodontists and 20 lay evaluators were asked to perform six Q-sorts on different photographs of 48 white female subjects. The six Q-sorts consisted of three different photographs for each of two time points (pre- and posttreatment), as follows: (1) smile-only, (2) face without the smile, and (3) face with the smile. The evaluators determined a split-line for attractive and unattractive images at the end of each Q-sort. The proportions of attractive patients were compared across Q-sorts using a Wilcoxon signed-rank test for paired data. The evaluators also ranked nine facial/dental characteristics at the completion of the six Q-sorts. Evaluators found the pretreatment face without the smile to be significantly more attractive than the face with the smile or the smile-only photographs. Dissimilar results were seen posttreatment; there was not a significant difference between the three posttreatment photographs. The two panels agreed on the proportion of "attractive" subjects but differed on the attractiveness level of each individual subject. The presence of a malocclusion has a negative impact on facial attractiveness. Orthodontic correction of a malocclusion affects overall facial esthetics positively. Laypeople and orthodontists agree on what is attractive. Overall facial harmony is the most important characteristic used in deciding facial attractiveness.

  2. Using stamping punch force variation for the identification of changes in lubrication and wear mechanism

    Science.gov (United States)

    Voss, B. M.; Pereira, M. P.; Rolfe, B. F.; Doolan, M. C.

    2017-09-01

    The growth in use of Advanced High Strength Steels in the automotive industry for light-weighting and safety has increased the rates of tool wear in sheet metal stamping. This is an issue that adds significant costs to production in terms of manual inspection and part refinishing. To reduce these costs, a tool condition monitoring system is required and a firm understanding of process signal variation must form the foundation for any such monitoring system. Punch force is a stamping process signal that is widely collected by industrial presses and has been linked closely to part quality and tool condition, making it an ideal candidate as a tool condition monitoring signal. In this preliminary investigation, the variation of punch force due to different lubrication conditions and progressive wear are examined. Linking specific punch force signature changes to developing lubrication and wear events is valuable for die wear and stamping condition monitoring. A series of semi-industrial channel forming trials were conducted under different lubrication regimes and progressive die wear. Punch force signatures were captured for each part and Principal Component Analysis (PCA) was applied to determine the key Principal Components of the signature data sets. These Principal Components were linked to the evolution of friction conditions over the course of the stroke for the different lubrication regimes and mechanism of galling wear. As a result, variation in punch force signatures were correlated to the current mechanism of wear dominant on the formed part; either abrasion or adhesion, and to changes in lubrication mechanism. The outcomes of this study provide important insights into punch force signature variation, that will provide a foundation for future work into the development of die wear and lubrication monitoring systems for sheet metal stamping.

  3. Reorienting Esthetic Knowing as an Appropriate "Object" of Scientific Inquiry to Advance Understanding of a Critical Pattern of Nursing Knowledge in Practice.

    Science.gov (United States)

    Bender, Miriam; Elias, Dina

    The esthetic pattern of knowing is critical for nursing practice, yet remains weakly defined and understood. This gap has arguably relegated esthetic knowing to an "ineffable" creativity that resists transparency and understanding, which is a barrier to articulating its value for nursing and its importance in producing beneficial health outcomes. Current philosophy of science developments are synthesized to argue that esthetic knowing is an appropriate "object" of scientific inquiry. Examples of empirical scholarship that can be conceived as scientific inquiry into manifestations of esthetic knowing are highlighted. A program of research is outlined to advance a science of esthetic knowing.

  4. Surface Roughness and Tool Wear on Cryogenic Treated CBN Insert on Titanium and Inconel 718 Alloy Steel

    International Nuclear Information System (INIS)

    Thamizhmanii, S; Mohideen, R; Zaidi, A M A; Hasan, S

    2015-01-01

    Machining of materials by super hard tools like cubic boron nitride (cbn) and poly cubic boron nitride (pcbn) is to reduce tool wear to obtain dimensional accuracy, smooth surface and more number of parts per cutting edge. wear of tools is inevitable due to rubbing action between work material and tool edge. however, the tool wear can be minimized by using super hard tools by enhancing the strength of the cutting inserts. one such process is cryogenic process. this process is used in all materials and cutting inserts which requires wear resistance. the cryogenic process is executed under subzero temperature -186° celsius for longer period of time in a closed chamber which contains liquid nitrogen. in this research, cbn inserts with cryogenically treated was used to turn difficult to cut metals like titanium, inconel 718 etc. the turning parameters used is different cutting speeds, feed rates and depth of cut. in this research, titanium and inconel 718 material were used. the results obtained are surface roughness, flank wear and crater wear. the surface roughness obtained on titanium was lower at high cutting speed compared with inconel 718. the flank wear was low while turning titanium than inconel 718. crater wear is less on inconel 718 than titanium alloy. all the two materials produced saw tooth chips. (paper)

  5. Hypohidrotic ectodermal dysplasia: a felicitous approach to esthetic and prosthetic management.

    Science.gov (United States)

    Singh, Tapan; Singh, Ronauk; Singh, Gurendra Pal; Singh, Jitender Pal

    2013-05-01

    Ectodermal dysplasia is a hereditary disease characterized by congenital dysplasia of one or more ectodermal structure and other accessory appendages. The oral manifestations are anodontia and poor bony foundation which impairs both esthetic as well as the masticatory function. The prosthodontic management of patients with such dysplastic condition necessitates a multidisciplinary approach. This case report describes the prosthodontic oral rehabilitation of a 16 years old female pediatric patient with ectodermal dysplasia. How to cite this article: Singh T, Singh R, Singh GP, Singh JP. Hypohidrotic Ectodermal Dysplasia: A Felicitous Approach to Esthetic and Prosthetic Management. Int J Clin Pediatr Dent 2013;6(2):140-145.

  6. Part-time occlusion therapy for anisometropic amblyopia detected in children eight years of age and older.

    Science.gov (United States)

    Lee, Young Rok; Lee, Ju Youn

    2006-09-01

    To determine the outcome of part-time occlusion therapy in children with anisometropic amblyopia detected after they were 8 years of age. We analyzed 29 eyes with anisometropic amblyopia in children 8 years of age and older. The mean age was 8.79 +/- 0.98 (range 8-12) years old. The subjects whose best-corrected visual acuity (BCVA) did not improve by two lines or better within 2 weeks of wearing glasses full-time were prescribed occlusion therapy for 6 hours a day outside of school hours, along with the instruction to wear glasses full-time. Subjects who complied with occlusion for more than 3 hours a day were considered to comply well. The major component of the anisometropia was hyperopia in 51.7% of the subjects, and hyperopia plus astigmatism was found in 24.1%. The mean pretreatment BCVA score was 0.51 0.23 (LogMAR). Compliance was 89.66%. The mean posttreatment BCVA was 0.03 +/- 0.01 (LogMAR), and the success rate, based on a posttreatment BCVA of 0.1 (LogMAR) and better, was 96.43%. It took an average of 4.79 +/- 3.35 months to reach the desired posttreatment BCVA. The mean posttreatment stereopsis was 79.78 +/- 37.61 seconds of arc. The recurrence rate was 8%. The visual improvement was related to the degree of compliance (p = 0.000). The time taken to reach the posttreatment BCVA was shorter in subjects with a better pretreatment BCVA (p = 0.019), but it did not relate to the compliance (p = 0.366). The most common component of anisometropia detected after 8 years of age was hyperopia. The part-time occlusion therapy, which had been carried out after school hours, was successful in most cases.

  7. Esthetic Evaluation of Implant Crowns and Peri-Implant Soft Tissue in the Anterior Maxilla: Comparison and Reproducibility of Three Different Indices.

    Science.gov (United States)

    Tettamanti, Sandro; Millen, Christopher; Gavric, Jelena; Buser, Daniel; Belser, Urs C; Brägger, Urs; Wittneben, Julia-Gabriela

    2016-06-01

    A successful implant reconstruction with optimal esthetics consists of a visually pleasing prosthesis and complete and healthy surrounding soft tissue. In the current literature, numerous indices used to qualitatively assess esthetics have been described. However, studies comparing the indices and their reproducibility are scarce. The aim of this study was to compare three different esthetic indices for the evaluation of single implant-supported crowns. A total of 10 prosthodontists (P), 10 orthodontists (O), 10 general dentists (G), and 10 lay people (L) independently performed the same assessment using 30 photographs and corresponding casts with three different esthetic indices (Peri-Implant and Crown Index [PICI], Implant Crown Aesthetic Index [ICAI], "Pink Esthetic Score/White Esthetic Score [PES/WES]) and repeated the evaluations 4 weeks later. The PES/WES and the PICI showed significantly higher esthetic scores (pink, white, total) and clinical acceptance compared with the ICAI in all four groups and in both assessments. The highest intraobserver agreement was achieved using the PES/WES and the least with the ICAI. The mean Kappa per group ranged from 0.18 (group L with ICAI) to 0.63 (group G with PICI). In comparison with the ICAI, the PES/WES and PICI were more reproducible. Therefore, PES/WES and PICI seem to be more suitable as esthetic indices for single implant crowns. © 2015 Wiley Periodicals, Inc.

  8. Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  9. [Individualized restorative designs and clinical evaluation for dental implants in the anterior esthetic zone with inappropriate conditions].

    Science.gov (United States)

    Dai, Wen-yong; Zhou, Guo-xing; Zhang, Xiao-zhen; Zhao, Yi; Wang, Jie; Yang, Yi; Zhu, Zhi-jun; Tang, Chun-bo

    2014-08-01

    To offer individualized restorative strategies for patients receiving dental implants in the anterior esthetic zone but with inappropriate available conditions and evaluate the clinical outcomes. Forty-six patients with 58 implants were recruited for the study in accordance with the criteria and received individualized implant prostheses in the anterior esthetic zone. The patients were followed up for 3-24 months, and the clinical outcomes were evaluated by pink and white esthetic scores (PES/WES). The patients were from 18 to 69 years old, and followed up for 12.6 months in average. According to the third month follow-up esthetic scores, for PES, 1.72% of the patients got low scores, 44.83% got medium scores and 53.45% got high scores; For WES, 0% got low scores, 20.69% got medium scores and 79.31% got high scores. No implant failure or peri-implantitis occurred. Individualized restorative designs for implants in the esthetic zone can effectively improve the appearance of the prostheses which originally have no appropriate available space. Close follow-up and monitoring of the peri-implant soft tissue and proper oral hygiene instructions are important to ensure the conditions of the prostheses.

  10. Assessment of wear facets produced by the ACTA wear machine

    DEFF Research Database (Denmark)

    Benetti, Ana R; Larsen, Liselotte; Dowling, Adam H

    2016-01-01

    . The mean wear depth was measured using the traditionally employed 2D and compared with the 3D profilometric (digital) techniques. Data were submitted to analyses of variance, Tukey's post hoc tests and Independent Samples Student's t-tests (where appropriate) at p...OBJECTIVE: To investigate the use of a three-dimensional (3D) digital scanning method in determining the accuracy of the wear performance parameters of resin-based composites (RBCs) determined using a two-dimensional (2D) analogue methodology following in-vitro testing in an Academisch Centrum...... for Tandheelkunde Amsterdam (ACTA) wear machine. METHODS: Specimens compatible with the compartments of the ACTA wear machine specimen wheel (n=10) were prepared from one commercial and four experimental RBCs. The RBC specimens were rotated against an antagonist wheel in a food-like slurry for 220,000 wear cycles...

  11. Influence of the cutting parameters on flank wear of coated inserts during turning of AISI 316L

    Directory of Open Access Journals (Sweden)

    Yusimit Zamora Hernández

    2015-03-01

    Full Text Available (Received: 2015/01/20 - Accepted: 2015/03/25The continuous improvement of manufacturing processes is critical to achieve optimum levels of productivity, quality and cut production of components and products. This research aims to determine the cutting tool flank wearing progression, during a high speed dry turning, for AISI 316L steel parts. Experimental data were acquired using two cutting feed levels, two material levels, three cutting speeds, and four principal cutting times. A scanning electron microscope (SEM was used to measure and analyze the wear of the cutting tools. Results were compared using analysis of variance and multiple regression for describing the relation between the variables used in the study. The analysis showed that the three layers coating insert did not exceed the end of life wearing criterion, while the one layer insert suffered a catastrophic wearing at the highest cutting speed. It was found that a relation exists between the experimental data and the predicted values for flank wear with a general average error of 4.1182%.

  12. Psychosocial impact of anterior dental esthetics on periodontal health, dental caries, and oral hygiene practices in young adults.

    Science.gov (United States)

    Solomon, Deborah; Katz, Ralph V; Bush, Anneke C; Farley, Victoria K; McGerr, Trevor J; Min, Hoon; Carbonella, Anthony M; Kayne, Joseph D

    2016-01-01

    This study sought to determine whether the self-perceived image of a young adult's anterior dental esthetics is linked with periodontal health, dental caries, and oral hygiene practices. Two hundred subjects were assessed via a clinical examination, including intraoral photographs. The subjects were questioned about their demographics and oral hygiene practices and given the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) to measure their self-perceived variables related to dental esthetics. A high PIDAQ score indicates a negative image of one's own dental esthetics, while a low PIDAQ score indicates a positive outlook. A self-perceived negative psychosocial impact of anterior dental esthetics was detected in subjects with higher levels of dental caries and visible gingival inflammation in the anterior region of the mouth.

  13. A study of wear in refrigerating machines using thin layer activation

    International Nuclear Information System (INIS)

    Hammer, P.; Eichhorn, K.; Eifrig, C.

    1986-01-01

    Wear is studied in a ball-and-socket joint of a newly developed refrigerating machine. Using deuteron activation a 15 μm deep Co-57 layer is generated at the ring-shaped friction area in the steel socket of the joint. The measurement of the Co-57 intensity of the wear particles held back on an oil filter provides information about the wear rate of the socket during machine operation. The measurement of the Co-57 contaminations occuring in the individual parts of the machine at the end of the test gives information about the distribution of the wear particles in the machine and about the material transfer in the ball-and-socket joint. (author)

  14. Assessment of the progression of tooth wear on dental casts

    NARCIS (Netherlands)

    Vervoorn-Vis, G.M.G.J.; Wetselaar, P.; Koutris, M.; Visscher, C.M.; Evälahti, M.; Ahlberg, J.; Lobbezoo, F.

    2015-01-01

    Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection

  15. Abrasive wear of ceramic wear protection at ambient and high temperatures

    Science.gov (United States)

    Varga, M.; Adam, K.; Tumma, M.; Alessio, K. O.

    2017-05-01

    Ceramic wear protection is often applied in abrasive conditions due to their excellent wear resistance. This is especially necessary in heavy industries conveying large amounts of raw materials, e.g. in steel industry. Some plants also require material transport at high temperatures and velocities, making the need of temperature stable and abrasion resistant wear protection necessary. Various types and wear behaviour of ceramic protection are known. Hence, the goal of this study is to identify the best suitable ceramic materials for abrasive conditions in harsh environments at temperatures up to 950°C and severe thermal gradients. Chamottes, known for their excellent thermal shock resistance are compared to high abrasion resistant ceramic wear tiles and a cost efficient cement-bounded hard compound. Testing was done under high-stress three-body abrasion regime with a modified ASTM G65 apparatus enabling for investigations up to ~950°C. Thereto heated abrasive is introduced into the wear track and also preheated ceramic samples were used and compared to ambient temperature experiments. Results indicate a significant temperature influence on chamottes and the hard compound. While the chamottes benefit from temperature increase, the cement-bounded hard compound showed its limitation at abrasive temperatures of 950°C. The high abrasion resistant wear tiles represented the materials with the best wear resistance and less temperature influence in the investigated range.

  16. Gingival esthetics and oral health-related quality of life in patients with cleft lip and palate.

    Science.gov (United States)

    Stelzle, F; Rohde, M; Oetter, N; Krug, K; Riemann, M; Adler, W; Neukam, F W; Knipfer, C

    2017-08-01

    While the oral health-related quality of life (OHRQoL) is known to be reduced in patients with cleft lip and palate (CLP), its inter-dependency with the soft tissue characteristics of the CLP area remains unclear. This study aimed to evaluate the soft tissue characteristics in the treated cleft area in order to investigate whether gingival esthetics correlate with OHRQoL. Thirty-six patients with unilateral or bilateral CLP (46 cleft areas) were investigated after secondary/tertiary alveolar bone grafting and orthodontic/prosthetic implant treatment using an adapted score to rate gingival esthetics (clinical esthetic score, CES). The patient's OHRQoL was determined using the German short version of the Oral Health Impact Profile questionnaire (OHIP-G14). The results showed a significantly better rating in patients with their own teeth in situ (12.05±1.10) than in patients with implants (6.95±4.78) or prosthetics (4.00±3.58). The best OHRQoL values were achieved by patients with their own teeth integrated into the cleft area (1.32±2.31), followed by patients with implants (2.33±2.33) and prosthetics (3.75±5.87). A significant (P=0.017) correlation was found between OHIP-G14 and CES scores, suggesting an increased OHRQoL in cases with higher oral esthetics in the cleft area. The therapeutic strategy contributes to both gingival esthetics and OHRQoL. The patient's subjective perception of OHRQoL can be attributed to objective gingival esthetic ratings. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Perception of smile esthetics by laypeople of different ages.

    Science.gov (United States)

    Sriphadungporn, Chompunuch; Chamnannidiadha, Niramol

    2017-12-01

    Age is a factor affecting smile esthetics. Three variables of smile esthetics associated with the maxillary anterior teeth and age-related changes have recently received considerable attention: (i) the incisal edge position of the maxillary central incisors, (ii) the maxillary gingival display, and (iii) the presence of a black triangle between the maxillary central incisors. The aim of this study was to evaluate the influence of age on smile esthetic perception based on these three variables in a group of Thai laypeople. The smiles were constructed from a photograph of a female smile. Smile photographs were altered in various increments using three variables: the incisal edge position of the maxillary incisors, gingival display, and a black triangle between the maxillary central incisors. The photographs were shown to a group of 240 Thai laypeople. The subjects were divided into two groups: a younger group, 15-29 years old (n = 120) and an older group, 36-52 years old (n = 120). Each subject was asked to score the attractiveness of each smile separately using a visual analog scale. Smile attractiveness scores concerning the incisal edge positions of the maxillary central incisors were similar between the two groups. However, upper lip coverage was rated as unattractive by the younger group. A gingival display of 0 and 2 mm was rated as most attractive by the younger group. Upper lip coverage and gingival display of 0 and 2 mm were considered attractive by the older group. Excessive gingival display (6 mm) was scored as unattractive by both groups. A black triangle ranging from 1 to 2.5 mm between the maxillary central incisors was scored differently between the two groups. The older group was more tolerant of the black triangle size. Age impacts smile perception based on maxillary gingival display and the presence of a black triangle between the maxillary central incisors, but not of the incisal edge position of the maxillary central incisors. Due to

  18. Wear resistance of polypropylene-SiC composite

    Science.gov (United States)

    Abenojar, J.; Enciso, B.; Martínez, MA; Velasco, F.

    2017-05-01

    In this work, the wear resistance of thermoplastic composites with a high amount of ceramic is evaluated. Composites made of polypropylene (PP) and silicon carbide (SiC) powder at 50 wt% were used with the final objective of manufacturing ablative materials. This is the first part of a project studying the wear resistance and the mechanical properties of those composites, to be used in applications like habitat industry. In theory, the exposure to high temperature of ablative materials involves the elimination of thermal energy by the sacrifice of surface polymer. In our case, PP will act as a heat sink, up to the reaction temperature (melting or sublimation), where endothermic chemical decomposition into charred material and gaseous products occurs. As the surface is eroded, it is formed a SiC like-foam with improved insulation performance. Composites were produced by extrusion and hot compression. The wear characterization was performed by pin-on-disk test. Wear test was carried out under standard ASTM G99. The parameters were 120 rpm speed, 15 N load, a alumina ball with 6 mm as pin and 1000 m sliding distance. The tracks were also observed by opto-digital microscope.

  19. Wear resistance of polypropylene-SiC composite

    International Nuclear Information System (INIS)

    Abenojar, J; Enciso, B; Martínez, MA; Velasco, F

    2017-01-01

    In this work, the wear resistance of thermoplastic composites with a high amount of ceramic is evaluated. Composites made of polypropylene (PP) and silicon carbide (SiC) powder at 50 wt% were used with the final objective of manufacturing ablative materials. This is the first part of a project studying the wear resistance and the mechanical properties of those composites, to be used in applications like habitat industry. In theory, the exposure to high temperature of ablative materials involves the elimination of thermal energy by the sacrifice of surface polymer. In our case, PP will act as a heat sink, up to the reaction temperature (melting or sublimation), where endothermic chemical decomposition into charred material and gaseous products occurs. As the surface is eroded, it is formed a SiC like-foam with improved insulation performance. Composites were produced by extrusion and hot compression. The wear characterization was performed by pin-on-disk test. Wear test was carried out under standard ASTM G99. The parameters were 120 rpm speed, 15 N load, a alumina ball with 6 mm as pin and 1000 m sliding distance. The tracks were also observed by opto-digital microscope. (paper)

  20. Development and validation of the German version of the Orofacial Esthetic Scale.

    Science.gov (United States)

    Reissmann, Daniel R; Benecke, Andreas W; Aarabi, Ghazal; Sierwald, Ira

    2015-07-01

    This study aimed to develop the German version of the Orofacial Esthetic Scale (OES-G) and to assess its psychometric properties. The OES is an eight-item instrument with seven items directly addressing esthetic impacts of the orofacial region and an eighth item for a global assessment. It applies an 11-point ordinal rating scale, with summary scores ranging from 0 (worst) to 70 (best). The original OES items were translated into German using a forward-backward method. A de novo development of German items (n = 21 patients) and a cross-cultural adaptation after pilot testing (n = 15 patients) established content validity. Internal consistency and construct validity (structural, convergent, known-groups) of the OES-G were assessed in a sample of 165 prosthodontic patients. The OES was applied in 42 patients on two occasions, with a temporal distance of 2-4 weeks apart to determine test-retest reliability. Internal consistency of the OES-G was considered as satisfactory (Cronbach's alpha 0.94; average inter-item correlation 0.64). Intraclass correlation coefficient of 0.95 (95 % confidence interval 0.92-0.98) indicated excellent test-retest reliability. Correlation matrix and exploratory factor analysis provided support for unidimensionality of the measured construct. The OES-G summary score was correlated with the patients' global assessment of their esthetics (r = 0.87) and external ratings of the expert group (r = 0.55) and discriminated patients with treatment need (39.4 points) from patients without (58.4 points; p esthetics.

  1. Esthetic, Functional, and Everyday Life Assessment of Individuals with Cleft Lip and/or Palate.

    Science.gov (United States)

    Gkantidis, Nikolaos; Papamanou, Despina A; Karamolegkou, Marina; Dorotheou, Domna

    2015-01-01

    To evaluate the level of satisfaction of individuals with cleft lip and/or palate (CLP) and their parents concerning the esthetic and functional treatment outcomes, the impact of the cleft on everyday life, and potential associations with treatment outcome satisfaction. The sample consisted of 33 patients (7 CP, 20 unilateral CLP, and 6 bilateral CLP; median age: 17.1, range: 9.0-33.1 years) and 30 parents, who responded to a questionnaire in an interview-guided session. All participants received their orthodontic treatment at the Department of Orthodontics in the University of Athens. Patients and their parents were quite satisfied with esthetics and function. Patients with UCLP primarily were concerned about nose esthetics (BCLP about lip esthetics and CP about speech). Increased satisfaction was associated with decreased influence of the cleft in everyday life (0.35 < rho < 0.64, P < 0.05). Parents reported significant influence of the cleft on family life, while patients did not. Despite the limited sample size of subgroups, the main concerns of patients with different cleft types and the importance of satisfying lip, nose, and speech outcomes for an undisturbed everyday life were quite evident. Thus, the need for targeted treatment strategies is highlighted for individuals with cleft lip and/or palate.

  2. Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

    NARCIS (Netherlands)

    Ligterink, D.J.

    1975-01-01

    The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

  3. Stochastic Distribution of Wear of Carbide Tools during Machining ...

    African Journals Online (AJOL)

    Journal of the Nigerian Association of Mathematical Physics ... The stochastic point model was used to determine the rate of wear distribution of the carbide tool ... Keywords: cutting speed, feed rate, machining time, tool life, reliability, wear.

  4. Esthetic Evaluation of Anterior Single-Tooth Implants with Different Abutment Designs - Patients' Satisfaction Compared to Dentists' Observations

    NARCIS (Netherlands)

    Patil, Ratnadeep; Gresnigt, Marco M M; Mahesh, Kavita; Dilbaghi, Anjali; Cune, Marco S

    Purpose: To correlate patients' satisfaction and dentists' observations regarding two abutment designs used for single crowns in the esthetic zone: a divergent one (control) and a curved one (experimental), with special emphasis on muco-gingival esthetics. Materials and Methods: Twenty-six patients

  5. Replacement of missing tooth in esthetic zone with implant-supported fixed prosthesis

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Full Text Available In the anterior region, the common reason for tooth loss is due to traumatic injury or congenital anomaly. Loss of a single tooth may cause functional and esthetic deficits to the patient. There are different treatment options available for replacing a missing incisor. Implant dentistry should be considered as first treatment alternative for replace a missing tooth. This case report presents the replacement of a missing maxillary left central incisor in a compromised site with dental implants along with bone graft followed by frenectomy to obtain a good clinical result and for better function and esthetics of the patient.

  6. Consequences of wear interruption for discomfort with contact lenses.

    Science.gov (United States)

    Papas, Eric B; Tilia, Daniel; Tomlinson, Daniel; Williams, Josh; Chan, Eddy; Chan, Jason; Golebiowski, Blanka

    2014-01-01

    To establish whether increased end-of-day discomfort during soft contact lens wear is associated with short-term changes occurring to the lens itself. Twenty-seven subjects wore hydrogel lenses (Focus Dailies; Alcon) bilaterally for 10 hours on two separate days. Comfort was reported using 1-100 numerical rating scales (1 = intolerable discomfort, 100 = lens cannot be felt). Day 1 ratings were taken before lens insertion and at 0.05, 5, and 10 hours post-insertion. Day 2 ratings occurred at similar times, but lenses were removed after the 5-hour assessment and either reinserted (n = 14) or newly replaced (n = 12). An additional rating was taken 5 minutes after re-insertion. Wear then continued to the 10-hour point. In a separate study, 24 different subjects repeated these procedures using a silicone hydrogel lens (AirOptix Aqua; Alcon) with wear taking place on 3 days to permit lens replacement to be with existing as well as new lenses in all subjects. For hydrogel lenses, comfort scores (mean ± 95% CI) reported after 10 hours were 79.4 ± 8.3 when lenses were worn un-replaced, compared with 73.2 ± 9.2 for replacement with the existing lens. When replacement was with a brand new lens, the corresponding values were 72.9 ± 10.9 (un-replaced) versus 69.2 ± 12.8 (new lens replacement). For silicone hydrogel lenses, 10-hour comfort was 90.3 ± 3.2 (un-replaced) versus 92.2 ± 2.9 (replacement with existing lens) versus 90.0 ± 3.3 (replacement with new lens). Differences between replacement conditions were not significant in any case (analysis of variance, p > 0.05). Final comfort was not influenced by replacing lenses midway through the wearing period. Comfort decrements experienced by users of these daily contact lenses towards the later part of the wearing period are not caused by changes occurring to the lenses on this time scale. Possible alternative etiological factors include a fatigue-like response in one or more ocular tissues or stimulation of ocular

  7. Gaussian process regression for tool wear prediction

    Science.gov (United States)

    Kong, Dongdong; Chen, Yongjie; Li, Ning

    2018-05-01

    To realize and accelerate the pace of intelligent manufacturing, this paper presents a novel tool wear assessment technique based on the integrated radial basis function based kernel principal component analysis (KPCA_IRBF) and Gaussian process regression (GPR) for real-timely and accurately monitoring the in-process tool wear parameters (flank wear width). The KPCA_IRBF is a kind of new nonlinear dimension-increment technique and firstly proposed for feature fusion. The tool wear predictive value and the corresponding confidence interval are both provided by utilizing the GPR model. Besides, GPR performs better than artificial neural networks (ANN) and support vector machines (SVM) in prediction accuracy since the Gaussian noises can be modeled quantitatively in the GPR model. However, the existence of noises will affect the stability of the confidence interval seriously. In this work, the proposed KPCA_IRBF technique helps to remove the noises and weaken its negative effects so as to make the confidence interval compressed greatly and more smoothed, which is conducive for monitoring the tool wear accurately. Moreover, the selection of kernel parameter in KPCA_IRBF can be easily carried out in a much larger selectable region in comparison with the conventional KPCA_RBF technique, which helps to improve the efficiency of model construction. Ten sets of cutting tests are conducted to validate the effectiveness of the presented tool wear assessment technique. The experimental results show that the in-process flank wear width of tool inserts can be monitored accurately by utilizing the presented tool wear assessment technique which is robust under a variety of cutting conditions. This study lays the foundation for tool wear monitoring in real industrial settings.

  8. Biotribocorrosion-an appraisal of the time dependence of wear and corrosion interactions: I. The role of corrosion

    International Nuclear Information System (INIS)

    Yan, Y; Neville, A; Dowson, D

    2006-01-01

    With the increasing interest in metal-on-metal (MoM) joint implants, studies have been focused on their wear and corrosion behaviour. Integrated electrochemical tests have been conducted and are reported in this paper. The corrosion, wear and wear-corrosion behaviour for three materials (high carbon CoCrMo, low carbon CoCrMo and UNS S31603) have been discussed. Corrosion effects on the overall performance for the three materials are analysed. Two distinct regimes have been found for the three materials: (a) the running-in regime and (b) the steady state regime, in line with other research. Even in the steady state regime, 20%-30% of the material degradation can be attributed to corrosion-related damage. High carbon CoCrMo showed excellent corrosion, wear and corrosion-wear resistance and therefore it delivered the best overall performance in terms of a lower wear rate, a lower friction coefficient and a higher resistance to corrosion

  9. The application of parameters for comprehensive smile esthetics by digital smile design programs: A review of literature

    Directory of Open Access Journals (Sweden)

    Doya Omar

    2018-01-01

    Full Text Available Cosmetic dentistry is increasingly becoming an issue of concern to patients who hope to improve their smile. A systematic and comprehensive dentofacial analysis must be performed before commencing esthetic treatment. Several computer software programs have been developed for digital smile design (DSD to assist clinicians in this process. This article compares DSD programs commonly used in cosmetic dentistry and their ability to assess esthetic parameters. A literature review was performed of current dentofacial aesthetic parameters and clinical applications of computer technology to assess facial, dentogingival and dental esthetics. Eight DSD programs (Photoshop CS6, Keynote, Planmeca Romexis Smile Design, Cerec SW 4.2, Aesthetic Digital Smile Design, Smile Designer Pro, DSD App and VisagiSMile were compared. Photoshop, Keynote and Aesthetic Digital Smile Design included the largest number of esthetic analysis parameters. Other studied DSD programs presented deficiencies in their ability to analyze facial esthetic parameters but included comprehensive dentogingival and dental esthetic functions. The DSD App, Planmeca Romexis Smile Design, and Cerec SW 4.2 were able to perform 3D analysis; furthermore, Cerec SW 4.2 and PRSD could be used jointly with CAD/CAM. The DSD App and Smile Designer Pro are available as mobile phone applications. It can be concluded that despite the fact that they were not specifically designed for dental diagnosis, Photoshop CS6 and Keynote provide a more comprehensive smile analysis than most specialized DSD programs. However, other program functions should also be considered when deciding which DSD program is applicable to individual clinical setups.

  10. Adhesion and wear properties of boro-tempered ductile iron

    International Nuclear Information System (INIS)

    Kayali, Yusuf; Yalcin, Yilmaz; Taktak, Suekrue

    2011-01-01

    Highlights: → In this study, the wear and adhesion properties of BDI were investigated. → Boro-tempering process under several heat treatment conditions was examined. → Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure. → It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons. -- Abstract: In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 o C for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 o C for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe 2 B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al 2 O 3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

  11. Radioactive ion implantation as a tool for wear measurements

    International Nuclear Information System (INIS)

    Bagger, C.; Soerensen, G.

    1979-01-01

    The present paper deals with ion implantation of radioactive krypton ions in surfaces with aim of measuring wear of different magnetic materials in sound-heads. The technique is especially suited for a relatively fast comparison of wear-characteristics of materials of varying composition in small inaccessible areas. In the present case utilisation of a 60 KeV accelerator allows determination of a total wear as small as 0.05 μm with an accuracy of 10%. Further the technique yields information of the time dependence of the wear process with an accuracy less than 0.001 μm. (author)

  12. The influence of professional competence on the inter- and intra-individual esthetic evaluation of implant-supported crowns in the anterior maxilla.

    Science.gov (United States)

    Petsos, Hari; Trimpou, Georgia; Eickholz, Peter; Lauer, Hans-Christoph; Weigl, Paul

    2017-04-01

    Evaluation of the influence of professional competence on esthetic predictability of implant-supported crowns in the anterior maxilla and identification of objective factors allowing predictable planning for esthetic results. Sixty patients with 82 implants in the esthetic zone were included in this study. Width of keratinized mucosa, biotype, recessions, and papilla index according to Jemt as well as radiological bone loss were assessed. Study casts and photographs were obtained. Each patient as well as people with different level of expertise (laypersons, students and dentists) rated the esthetic satisfaction after final restoration on a scale (1-10). Correlations between esthetic assessments and previously documented clinical parameters were tested. The study failed to show a significant relationship between the raters' level of dental expertise and their subjective esthetic evaluation. However, patients rated themselves much more favorable than the three evaluator groups did. A comparison of the clinical parameters with the esthetic evaluation revealed significantly more favorable ratings by the lay group in the presence of a wide attached gingiva (P = 0.021) than by the other groups and by the laypersons (P = 0.002), the dentists (P = 0.003), and students (P = 0.009) in the absence of recessions. The ratio of the implant crown length to the length of the contralateral crown had a negative effect on ratings for all three groups ([laypersons P esthetic predictability of implant-supported crowns in the anterior maxilla in laypersons' ratings. Furthermore, there is an association between the discrepancy of lengths of implant-supported single crowns to their contralateral natural teeth and esthetic satisfaction for all expertise levels. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Anthropology, tooth wear, and occlusion ab origine.

    Science.gov (United States)

    Young, W G

    1998-11-01

    The purpose of this essay is to emphasize that anthropology, the study of man in his environments, is a potent tool for scientific discovery and inspiration in dental science. It attempts to capture flashes of creative anthropological insight which have illuminated studies of tooth wear and occlusion in the past. While it documents contributions, understandings, and misunderstandings from Australian and New Zealand dentists, it is not a hagiography. The real saint of this essay is the Australian aborigine. For when men and women are understood in their environments, much is learned from them which challenges preconceptions of our dental science culture. The essay concludes that new, contemporary Australian culture needs to be studied by anthropological approaches if we are to understand how dental erosion is exacerbating tooth wear and damaging the occlusions of contemporary Australians. Much remains to be discovered about contemporary lifestyles, habits, and diets that lead to dental erosion, the principal cause of contemporary tooth wear in this part of the world.

  14. Research on Oxidation Wear Behavior of a New Hot Forging Die Steel

    Science.gov (United States)

    Shi, Yuanji; Wu, Xiaochun

    2018-01-01

    Dry sliding tests for the hot forging die steel DM were performed in air under the test temperature at 400-700 °C and the time of 0.5-4 h by a UMT-3 high-temperature wear tester. The wear behavior and characteristics were studied systematically to explore the general characters in severe oxidation conditions. The results showed that a mild-to-severe oxidation wear transition occurred with an increase in the test temperature and duration. The reason was clarified as the unstable M6C carbides coarsening should be responsible for the severe delamination of tribo-oxide layer. More importantly, an intense oxidation wear with lower wear rates was found when the experimental temperature reaches 700 °C or after 4 h of test time at 600 °C, which was closely related to the degradation behavior during wear test. Furthermore, a new schematic diagram of oxidation wear of DM steel was proposed.

  15. [Application of target restoration space quantity and quantitative relation in precise esthetic prosthodontics].

    Science.gov (United States)

    Haiyang, Yu; Tian, Luo

    2016-06-01

    Target restoration space (TRS) is the most precise space required for designing optimal prosthesis. TRS consists of an internal or external tooth space to confirm the esthetics and function of the final restoration. Therefore, assisted with quantitive analysis transfer, TRS quantitative analysis is a significant improvement for minimum tooth preparation. This article presents TRS quantity-related measurement, analysis, transfer, and internal relevance of three TR. classifications. Results reveal the close bond between precision and minimally invasive treatment. This study can be used to improve the comprehension and execution of precise esthetic prosthodontics.

  16. [Reciprocal relationships between orthodontics and periodontics in esthetic treatments].

    Science.gov (United States)

    Monnet-Corti, Virginie; Barrin, Arnaud; Goubron, Cyril

    2012-06-01

    The objective of this article is to review various unsightly periodontal defects and the treatments that have previously been used to eliminate them in order to establish guidelines for future therapy. The inter-relationship between orthodontic and periodontal disciplines is well established and needs no defense here. Periodontal tissues change throughout life and the same is true for the smile. The periodontium is an essential component of the appearance of the face as well as the lips. These are dynamic esthetic criteria while the gingiva and the static character of the dentition also contribute to the character of an individual's smile. In order to conduct orthodontic therapy most effectively it is essential that orthodontists and periodontists utilize a coordinated approach. From the beginning, they must establish an etiological diagnosis of any esthetic defects that will insure that their joint therapy is conducted appropriately and at the proper moment. © EDP Sciences, SFODF, 2012.

  17. Towards the effective tool wear control in micro-EDM milling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Valentincic, J.; Hansen, Hans Nørgaard

    2010-01-01

    The electrode wear in micro-electrical discharge milling (micro-EDM milling) is one of the main problems to be solved in order to improve machining accuracy. This paper presents an investigation on wear and material removal in micro-EDM milling for selected process parameter combinations typical...... of the accuracy of volume measurements on the electrode wear per discharge and on the material removal per discharge are discussed, and the issues limiting the applicability of real time wear sensing in micro-EDM milling are presented....

  18. Carbon-Based Wear Coatings: Properties and Applications

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2003-01-01

    and friction; thermal conductivity; chemical and thermal inertness; corrosion and wear resistance; radiation resistance and biocompatibility; electronic, acoustic, and electrochemical characteristics; and environmental compatibility. These properties make diamond attractive for a wide range of diverse applications. In particular, chemical-vapor-deposited (CVD) diamond coatings offer a broad potential, since size and cost are not as limiting. The production of large, superhard diamond films or sheets at low cost make designer materials possible. This presentation is divided into two sections: properties and applications of hard coatings. The first section is concerned with the fundamental properties of the surfaces of CVD diamonds and related materials. The surface properties of hard coatings with favorable coefficients of friction (less than or equal to 0.1) and dimensional wear coefficients (less than or equal to 10(exp -6) cubic millimeters/N.m) in specific environments are discussed. The second section is devoted to applications. Examples of actual, successful applications and of potential challenging applications of the coatings.such as CVD diamond, diamondlike carbon, and cubic boron nitride-are described. Cutting tools coated with CVD diamond are of immediate commercial interest. Other applications, such as microelectromechanical systems (MEMS), valves, and bearings of CVD diamond, are being developed, but at a slow pace. There is a continually growing interest in commercializing diamondlike carbon for wear parts applications, such as biomedical parts and implants, forming dies, transport guides, magnetic tapes and disks, valves, and gears. Cubic boron nitride films are receiving attention because they can be used on tools to machine ferrous materials or on wear parts in sliding contact with ferrous materials.

  19. Abrasive wear of intermetallics

    International Nuclear Information System (INIS)

    Hawk, J.A.; Alman, D.E.; Wilson, R.D.

    1995-01-01

    The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

  20. Influence of restorative materials on color of implant-supported single crowns in esthetic zone: A spectrophotometric evaluation

    DEFF Research Database (Denmark)

    M., Peng; W.-J., Zhao; M., Hosseini

    2017-01-01

    of the esthetic outcome of soft tissue around implant-supported single crowns in the anterior zone, and the crown color match score was used for subjective evaluation of the esthetic outcome of implant-supported restoration. ANOVA analysis was used to compare the differences among groups and Spearman correlation...

  1. The role of hardness and microstructure in high temperature pitting in the impact wear of 9Cr boiler material. Part 1

    International Nuclear Information System (INIS)

    Morri, J.

    1987-11-01

    This report describes impact wear experiments on 9Cr1Mo finned boiler tube specimens in 3 different heat treated forms. The objective of the tests was to establish whether a high temperature, high wear rate, pitting form of wear was dependent upon the residual microstructure and hardness. Although a x2 reduction in specific wear rate was achieved for the martensitic structure, the pitting characteristic remained. It is concluded that modifying the as-received 9Cr microstructure has not suppressed the high temperature severe form of wear. (author)

  2. Pushing for Part Time.

    Science.gov (United States)

    Geber, Beverly

    1987-01-01

    More employees are choosing to work part time. Although this trend started because of working women, some men are choosing part-time positions. Part-time employees forfeit salary and promotion potential, yet most feel the trade is fair and that they are more productive during their working hours. (CH)

  3. Friction and wear in hot forging of steels

    International Nuclear Information System (INIS)

    Daouben, E.; Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A.; Truong-Dinh, N.; Lazzarotto, L.

    2007-01-01

    In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200 deg. C. A nitrided contactor representing the tool is heated at 200 deg. C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants

  4. Guidelines for patient-specific jawline definition with titanium implants in esthetic, deformity, and malformation surgery

    OpenAIRE

    Mommaerts, Maurice Yves

    2016-01-01

    Context: Asymmetry and unfavorable esthetics of the jawline have become possible to correct in three dimensions using computer aided design and computer aided manufacturing. Aims: The aim of this study was to provide esthetic, technical, and operative guidelines for mandibular angle and border augmentation using patient-specific titanium implants made by selective laser melting. Settings and Design: University hospital - prospective registry. Subjects and Methods: Twelve patients and 17 impla...

  5. Longevity, Esthetic Perception, and Psychosocial Impact of Teeth Bleaching by Low (6%) Hydrogen Peroxide Concentration for In-office Treatment: A Randomized Clinical Trial.

    Science.gov (United States)

    Fernández, E; Bersezio, C; Bottner, J; Avalos, F; Godoy, I; Inda, D; Vildósola, P; Saad, Jrc; Oliveira, O B; Martín, J

    The aim was to evaluate the color longevity after nine months of in-office bleaching with gel (6% hydrogen peroxide), to compare this to a control concentration of 35% in a split-mouth study model, and to assess the dental confidence and psychosocial impact on patients. Twenty-seven patients were assessed at the nine-month recall. The bleaching procedure with 6% or 35% hydrogen peroxide gel was performed randomly in the upper hemi-arch of each patient. The color was measured at baseline and at one week, one month, and nine months after the procedure, using the Vita Easyshade spectrophotometer, the Vita classical shade guide organized by value, and Vita Bleach Guide 3DMaster. Moreover, two surveys, OHIP-Esthetics and PIDAQ, were used to assess the esthetic self-perception and psychosocial impact of the bleaching procedure. During the nine-month recall, the color was assessed before and after dental prophylaxis. Twenty-seven patients participated in the nine-month recall. There was a significant difference in ΔE between the two groups at all times assessed (p0.20). There was no significant difference in ΔSGU at all times (p>0.05). There was a significant difference in OHIP-Esthetics and PIDAQ sums compared with baseline scores (p<0.03). The two compounds remained effective at nine months, with a slight rebound of color, and maintained their objective color difference but not the subjective color difference. Patients were satisfied with the bleaching procedure, and this had a positive impact on esthetic perception and a positive psychosocial impact at the nine-month recall.

  6. High-risk esthetically driven restoration: begin with the end in mind.

    Science.gov (United States)

    Ricciardi, Michael T; Pizzi, Peter

    2013-03-01

    A high-risk esthetically driven restorative case requires the dental team, along with the patient, to have a clear vision of the final outcome. In this case of a 33-year-old woman who wanted to improve her smile, esthetic problems stemmed from a retained deciduous maxillary left canine along with an impacted tooth No. 11. Among a number of concerns was the shape and color of the deciduous canine and the uneven length of the maxillary central incisors. A treatment plan that included orthodontics with removable aligners, occlusal adjustment, composite restorations, extraction and implant placement, indirect porcelain veneers, and a custom abutment and PFM crown was successfully executed in four phases over the course of more than 4 years.

  7. Effect of prophylactic polishing protocols on the surface roughness of esthetic restorative materials.

    Science.gov (United States)

    Neme, A L; Frazier, K B; Roeder, L B; Debner, T L

    2002-01-01

    Many polishing protocols have been evaluated in vitro for their effect on the surface roughness of restorative materials. These results have been useful in establishing protocols for in vivo application. However, limited research has focused on the subsequent care and maintenance of esthetic restorations following their placement. This investigation evaluated the effect of five polishing protocols that could be implemented at recall on the surface roughness of five direct esthetic restorative materials. Specimens (n=25) measuring 8 mm diameter x 3 mm thick were fabricated in an acrylic mold using five light-cured resin-based materials (hybrid composite, microfilled composite, packable composite, compomer and resin-modified glass ionomer). After photopolymerization, all specimens were polished with Sof-Lex Disks to produce an initial (baseline) surface finish. All specimens were then polished with one of five prophylactic protocols (Butler medium paste, Butler coarse paste, OneGloss, SuperBuff or OneGloss & SuperBuff). The average surface roughness of each treated specimen was determined from three measurements with a profilometer (Surface 1). Next, all specimens were brushed 60,000 times at 1.5 Hz using a brush-head force of 2 N on a Manly V-8 cross-brushing machine in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness of each specimen was measured after brushing (Surface 2) followed by re-polishing with one of five protocols, then final surface roughness values were determined (Surface 3). The data were analyzed using repeated measures ANOVA. Significant differences (p=0.05) in surface roughness were observed among restorative materials and polishing protocols. The microfilled and hybrid resin composite yielded significantly rougher surfaces than the other three materials following tooth brushing. Prophylactic polishing protocols can be used to restore a smooth surface on resin-based esthetic restorative materials following simulated tooth

  8. User experiences of wearable activity monitor among 3-6-year-old preschool children – Are children willing to wear monitor 7 days 24 hours per day?

    Directory of Open Access Journals (Sweden)

    Suvi Määttä

    2015-10-01

    This study was conducted as a part of long-term DAGIS project that aims to improve the health behaviors and diminish socioeconomic inequalities in health behaviors among preschool children in Finland. A large cross-sectional survey is conducted in autumn 2015. Children (N=800, aged 3-6 years wear Actigraph WGT3X-BT accelerometer for seven days, 24 hours per day. Simultaneously with accelerometer use, parents fill in diary with informing the user experiences of accelerometer and possible non-wearing times. Parents are advised that the child wears accelerometer 24 hours and remove the belt only when in water (e.g. in shower. The accelerometer data are checked straight after data collection. Choi (2011 wear time analyses are conducted for data. The device acceptability, compliance for wearing times and reported barriers for using accelerometer 24 hours in seven days among 3-6-year-old children are reported. Conclusions This study provides new information about the usability of wearable activity monitors among 3-6-year-old children, an age group that is less studied.

  9. Analysis of mechanism of carbide tool wear and control by wear process

    Directory of Open Access Journals (Sweden)

    Pham Hoang Trung

    2017-01-01

    Full Text Available The analysis of physic-mechanical and thermal physic properties of hard alloys depending on their chemical composition is conducted. The correlation of cutting properties and regularities of carbide tool wear with cutting conditions and thermal physic properties of tool material are disclosed. Significant influence on the tool wear of not only mechanical, but, in the first place, thermal physic properties of tool and structural materials is established by the researches of Russian scientists, because in the range of industrial used cutting speeds the cause of tool wear are diffusion processes. The directions of intensity decreasing of tool wear by determining rational processing conditions, the choice of tool materials and wear-resistant coating on tool surface are defined.

  10. From observation to understanding: Approach to analysis of wear mechanisms, Case of RCCAs and CRDM latch arms

    International Nuclear Information System (INIS)

    Hertz, D.

    2004-01-01

    Component wear can affect the ability of a component to fulfill its required function. For a designer or user, it is reasonable to expect possible wear occurrence as soon as parts are in relative motion. It is less obvious to extend this possibility to motions with small or very small amplitudes and loads. However, it has to be admitted that such cases exist. It then becomes imperative to determine the wear mechanisms so that the lifetime of the components and the optimum date of their replacement can be predicted or the degradation can be remedied. For this purpose, standard and widely accepted practice is to carry out simulator tests. Through examples of wear from nuclear reactor components such as the RCCAs (Rod Cluster Control Assembly) and the CRDM (Control Rod Drive Mechanism) latch arms, an approach for understanding the wear mechanisms and controlling their effects can be undertaken. Cases of wear have been observed on real-life parts, but the first simulator tests have shown deviations from in-reactor behaviour. Comparative examination of the wear facies of actual parts which have operated in reactor or simulators, both control rods and CRDM latch arms, was the key starting point for a new analytical approach, incorporating the formulation of wear mechanism hypotheses which can account for the observed facies. Expert assessment thus highlighted the importance of the environment by revealing that the wear featured a large component linked to friction-assisted corrosion. By including this tribo-corrosion aspect, it became possible to reach understanding of the mechanisms and account for the wear observed in reactor and on simulators. Further well-controlled simulator tests then made it possible to verify the importance of the tribo-corrosion processes in a pressurized water medium. Analysis of the physical chemical behaviour of the original materials (austenitic stainless steel) also explains why these surface modifications limit or remedy wear

  11. Influence of nitrogen ion implantation on wear studied by a new laboratory wear test

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, E.; Paszti, F.; Vertessy, Z. (Central Research Inst. for Physics, Hungarian Academy of Sciences, Budapest (Hungary))

    1991-05-01

    A new laboratory wear test is developed in which the wear trace is measured by Rutherford backscattering spectrometry. The advantage of the new test is that the wear rate is directly determinable. The new test setup has been used to study the effects of nitrogen implantation on the wear processes on 115CrV3 steel. The wear rate decreases by a factor of 2 at 4x10{sup 17} N{sup +}/cm{sup 2} implanted dose. (orig.).

  12. Wear resistance of layers hard faced by the high-alloyed filler metal

    OpenAIRE

    Dušan Arsić; Vukić Lazić; Ruzica R. Nikolic; Milan Mutavdžić; Srbislav Aleksandrović; Milan Djordjević

    2016-01-01

    The objective of this work was to determine the wear resistance of layers hard faced by the high-alloyed filler metal, with or without the austenite inter-layer, on parts that operate at different sliding speeds in conditions without lubrication. The samples were hard faced with the filler metal E 10-UM-60-C with high content of C, Cr and W. Used filler metal belongs into group of alloys aimed for reparatory hard facing of parts damaged by abrasive and erosive wear and it is characterized by ...

  13. Recognition of patient-reported impairment in oral aesthetics

    DEFF Research Database (Denmark)

    Dannemand Jensen, Katrine; Øzhayat, Esben Boeskov

    2014-01-01

    Scale (OES). Background variables were: gender, age, work-situation, education-level, marital status, number and location of teeth, wearing a removable dental prosthesis (RDP), and smile line. Results: A significant correlation was found between the overall professional evaluation and the OHIP-Aes score...... of prosthodontic replacements. The oral esthetics was professionally evaluated using the Prosthetic Esthetic Index (PEI), compiling 13 different esthetic aspects and an overall evaluation. The patient-reported impairment was evaluated using the Oral Health Impact Profile Aesthetic (OHIP-Aes) and the Oral Esthetic...

  14. Overview of PVD wear resistant coatings

    International Nuclear Information System (INIS)

    Teeter, F.J.

    1999-01-01

    The combined functionality of wear-resistant and low-friction multilayer coatings has widened application possibilities for a new generation of coated tools. For the first time tool wear mechanisms are comprehensively addressed both at the cutting edge and contact areas away from the edge where chip evacuation is facilitated. Since its recent market introduction a combined TiA1N and WC/C PVD coating has been proven to increase cutting performance in various metal cutting operations, notably drilling and tapping of steels and aluminum alloys. Significant improvements have been obtained under dry as well as with coolant conditions. The results of laboratory metal cutting tests and field trials to date will be described. Correlations between chip formation / wear mechanisms and coating properties are given to explain the effectiveness of this coating. (author)

  15. Investigation of wear land and rate of locally made HSS cutting tool

    Science.gov (United States)

    Afolalu, S. A.; Abioye, A. A.; Dirisu, J. O.; Okokpujie, I. P.; Ajayi, O. O.; Adetunji, O. R.

    2018-04-01

    Production technology and machining are inseparable with cutting operation playing important roles. Investigation of wear land and rate of cutting tool developed locally (C=0.56%) with an HSS cutting tool (C=0.65%) as a control was carried out. Wear rate test was carried out using Rotopol -V and Impact tester. The samples (12) of locally made cutting tools and one (1) sample of a control HSS cutting tool were weighed to get the initial weight and grit was fixed at a point for the sample to revolve at a specific time of 10 mins interval. Approach of macro transfer particles that involved mechanism of abrasion and adhesion which was termed as mechanical wear to handle abrasion adhesion processes was used in developing equation for growth wear at flank. It was observed from the wear test that best minimum wear rate of 1.09 × 10-8 and 2.053 × 10-8 for the tools developed and control were measured. MATLAB was used to simulate the wear land and rate under different conditions. Validated results of both the experimental and modeling showed that cutting speed has effect on wear rate while cutting time has predicted measure on wear land. Both experimental and modeling result showed best performances of tools developed over the control.

  16. Adhesive Bonding to Computer-aided Design/ Computer-aided Manufacturing Esthetic Dental Materials: An Overview.

    Science.gov (United States)

    Awad, Mohamed Moustafa; Alqahtani, H; Al-Mudahi, A; Murayshed, M S; Alrahlah, A; Bhandi, Shilpa H

    2017-07-01

    To review the adhesive bonding to different computer-aided design/computer-aided manufacturing (CAD/CAM) esthetic restorative materials. The use of CAD/CAM esthetic restorative materials has gained popularity in recent years. Several CAD/ CAM esthetic restorative materials are commercially available. Adhesive bonding is a major determinant of success of CAD/ CAM restorations. Review result: An account of the currently available bonding strategies are discussed with their rationale in various CAD/ CAM materials. Different surface treatment methods as well as adhesion promoters can be used to achieve reliable bonding of CAD/CAM restorative materials. Selection of bonding strategy to such material is determined based on its composition. Further evidence is required to evaluate the effect of new surface treatment methods, such as nonthermal atmospheric plasma and self-etching ceramic primer on bonding to different dental ceramics. An understanding of the currently available bonding strategies to CA/CAM materials can help the clinician to select the most indicated system for each category of materials.

  17. Allowable stem nut wear and diagnostic monitoring for MOVs

    International Nuclear Information System (INIS)

    Swinburne, P.

    1994-01-01

    After a motor-operated valve (MOV) stem nut failure in 1991 that contributed to a forced plant shutdown, the FitzPatrick Plant staff developed criteria to check for excessive stem nut wear in MOVs. Allowable stem nut wear monitoring uses both direct dimensional measurement and diagnostic test data interpretation. The wear allowance is based on the recommended permitted backlash discussed in the Electric Power Research Institute/Nuclear Maintenance Assistance Center Technical Repair Guideline for the Limitorque SMB-000 Motor Actuator. The diagnostic analysis technique measures the time at zero load and compares this with a precalculated allowable zero force time. Excessive zero force time may be the result of other MOV problems, such as a loose stem nut lock nut or excessive free play in the drive sleeve bearing. Stress levels for new or nominal stem nuts and stem nuts with the full wear allowance were compared. Bending and shear stresses at the thread root increase for the maximum wear condition when compared with a open-quotes newclose quotes stem nut. These stresses are directly related to the thread root thickness. For typical MOV loading and common stem threading (with two diameters of thread engagement), the thread stresses are well within acceptable limits for ASTM B584-C86300 (formerly B147-863) manganese bronze (typical stem nut material)

  18. Immediate Reconstruction of Failed Implants in the Esthetic Zone Using a Flapless Technique and Autogenous Composite Tuberosity Graft

    NARCIS (Netherlands)

    Raghoebar, Gerry M; Meijer, Henny J A; van Minnen, Baucke; Vissink, Arjan

    We describe a technique for immediate reconstruction of bone after removal of failed dental implants in the esthetic region to optimize the esthetic outcome of retreatment. We conducted a study of 16 consecutive patients in whom the bony defect resulting from implant removal was immediately

  19. Esthetic management of mucogingival defects after excision of epulis using laterally positioned flaps.

    Science.gov (United States)

    Xie, Yu-feng; Shu, Rong; Qian, Jie-lei; Lin, Zhi-kai; Romanos, Georgios E

    2015-03-01

    Epulis is a benign hyperplasia of the oral soft tissues. Surgical excision always extends to the periosteum and includes scaling of adjacent teeth to remove any possible irritants. The esthetics of the soft tissues may be compromised, however. This article studies three cases in which an immediate laterally positioned flap (LRF) was used to repair mucogingival defects after epulis biopsies. After 24 months, the color and shape of the surgical areas were healthy and stable, nearly complete root coverage was evident, and no lesions reoccurred. For repairing gingival defects after biopsy, LRF appears to be minimally traumatic while promoting esthetic outcomes.

  20. Wear resistance of TiB/sub 2/-Fe cermets

    International Nuclear Information System (INIS)

    Champagne, B.; Dallaire, S.

    1985-01-01

    A material which consists of TiB/sub 2/ dispersed in an iron matrix was synthesized by the exothermic reaction of ferrotitanium and boron. The as-reacted products were hot isostatically pressed to produce TiB/sub 2/-Fe cermets. The influence of HIP variables on the density and total fractional porosity of specimens is presented. Density above 95% is obtained by HIPping at temperatures below 1300 0 C. Increasing the temperature and the time of HIPping enhance the mechanical properties and wear resistance of TiB/sub 2/-Fe cermets by reducing their residual porosity. Relations obtained by regression analysis showed that the porosity strongly affects the properties of parts. Regression analysis point out that the wear loss of a 5% porosity TiB/sub 2/-Fe cermet is 270% higher than a dense HIPped cermet. Low stress and high stress abrasion resistance tests utilizing various abrasive media were carried out on dense HIPped cermets and results were compared with those obtained from WC-Co cermets and 1020 steel

  1. Steam generator fretting-wear damage: A summary of recent findings

    International Nuclear Information System (INIS)

    Guerout, F.M.; Fisher, N.J.

    1999-01-01

    Flow-induced vibration of steam generator (SG) tubes may sometimes result in fretting-wear damage at the tube-to-support locations. Fretting-wear damage predictions are largely based on experimental data obtained at representative test conditions. Fretting-wear of SG materials has been studied at the Chalk River Laboratories for two decades. Tests are conducted in fretting-wear test machines that simulate SG environmental conditions and tube-to-support dynamic interactions. A new high-temperature force and displacement measuring system was developed to monitor tube-to-support interaction (i.e., work-rate) at operating conditions. This improvement in experimental fretting-wear technology was used to perform a comprehensive study of the effect of various environment and design parameters on SG tube wear damage. This paper summarizes the results of tests performed over the past 4 yr to study the effect of temperature, water chemistry, support geometry, and tube material on fretting-wear. The results show a significant effect of temperature on tube wear damage. Therefore, fretting-wear tests must be performed at operating temperatures in order to be relevant. No significant effect of the type of water treatment on tube wear damage was observed. For predominantly impacting motion, the wear of SG tubes in contact with 410 stainless steel is similar regardless of whether Alloy 690 or Alloy 800 is used as tubing material or whether lattice bars or broached hole supports are used. Based on results presented in this paper, an average wear coefficient value is recommended that is used for the prediction of SG tube wear depth versus time

  2. Visibility of gingiva - An important determinant for an esthetic smile.

    Science.gov (United States)

    Sepolia, Shipra; Sepolia, Gaurav; Kaur, Rupinder; Gautam, Devendar Kumar; Jindal, Vikas; Gupta, Subhash Chander

    2014-07-01

    Need for having better esthetics is the new emerging trend seen in patients' demands and expectations. Various periodontal procedures including the mucogingival procedures have been designed to enhance the esthetics. The amount of gingival display of the patient is also an important parameter while considering the esthetics of the patient. Till date, very few studies have been done in which the amount of gingival visibility have been determined. So, the aim of this study was to evaluate the amount of visibility of gingiva during natural smile and forced smile in the patients visiting Himachal Dental College and Hospital. A total of 400 patients (242 females and 158 males), aged between 18 to 49 years, attending the outpatient department of Himachal Dental College, were included in this study. Patients were divided into two groups according to age and gender. Clinical photographs of the patients were taken and analyzed according to the following classification: (1) Very high smile line that is more than 2 mm of marginal gingiva visible or more than 2 mm apical to the cementoenamel junction visible for the reduced but healthy periodontium, (2) high smile line that is between 0 and 2 mm of marginal gingiva visible or between 0 and 2 mm apical to the cementoenamel junction visible for the reduced but healthy periodontium, (3) average smile line in which only gingival embrasures are visible, (4) low smile line in which gingival embrasures and cementoenamel junction not visible. Examination of the gingiva was done for both natural smile and forced smile. During smile analysis, the following results were revealed for Natural smile and forced smile. Natural smile analysis revealed following: C1: 1%, C2: 6%, C3: 43.50% and C4 was 49.50%. Forced smile analysis revealed the following: C1: 1%, C2: 15.50%, C3: 59% and C4: 24.50%. Excessive gingival display is an esthetic concern both to the patient and clinician. Therefore, understanding the etiology and treatment options is

  3. Visibility of gingiva - An important determinant for an esthetic smile

    Directory of Open Access Journals (Sweden)

    Shipra Sepolia

    2014-01-01

    Full Text Available Background: Need for having better esthetics is the new emerging trend seen in patients′ demands and expectations. Various periodontal procedures including the mucogingival procedures have been designed to enhance the esthetics. The amount of gingival display of the patient is also an important parameter while considering the esthetics of the patient. Till date, very few studies have been done in which the amount of gingival visibility have been determined. So, the aim of this study was to evaluate the amount of visibility of gingiva during natural smile and forced smile in the patients visiting Himachal Dental College and Hospital. Materials and Methods: A total of 400 patients (242 females and 158 males, aged between 18 to 49 years, attending the outpatient department of Himachal Dental College, were included in this study. Patients were divided into two groups according to age and gender. Clinical photographs of the patients were taken and analyzed according to the following classification: (1 Very high smile line that is more than 2 mm of marginal gingiva visible or more than 2 mm apical to the cementoenamel junction visible for the reduced but healthy periodontium, (2 high smile line that is between 0 and 2 mm of marginal gingiva visible or between 0 and 2 mm apical to the cementoenamel junction visible for the reduced but healthy periodontium, (3 average smile line in which only gingival embrasures are visible, (4 low smile line in which gingival embrasures and cementoenamel junction not visible. Examination of the gingiva was done for both natural smile and forced smile. Results: During smile analysis, the following results were revealed for Natural smile and forced smile. Natural smile analysis revealed following: C1: 1%, C2: 6%, C3: 43.50% and C4 was 49.50%. Forced smile analysis revealed the following: C1: 1%, C2: 15.50%, C3: 59% and C4: 24.50%. Conclusions: Excessive gingival display is an esthetic concern both to the patient and

  4. Assessment of fretting wear in Hanaro fuel

    International Nuclear Information System (INIS)

    Chae, Hee Taek; Lim, Kyeong Hwan; Kim, Hark Rho

    1999-06-01

    Since the first fuel loading on Feb. 1995, various zero-power tests were performed in HANARO and power ascending tests followed. After the initial fuel loading, Hanaro operation staffs inspected only two fuel bundles which were evaluated to have the highest power at the end of each cycle and they did not recognize anything peculiar in the inspected bundles. At the end of 1996, Hanaro staffs found severe wear damages in the fuel components. After that, the 4th cycle core was re-arranged with fresh fuels only to investigate wear phenomena on the fuel components. The fuel inspections have been performed 25 times periodically since the core re-configuration. In this report, fretting wear characteristics of the fuel assemblies were evaluated and summarized. Wear damages of the improved fuel assembly to resolve the wear problem were compared with those of the original fuel assembly. Based on the results of the fuel inspections, we suggest that fuel inspection need not be done for the first 60 pump operation days in order to reduce the potential of damage by a fuel handling error and an operator's burden of the fuel inspection. (author). 6 refs., 10 tabs., 5 figs

  5. Clinician assessments and patient perspectives of single-tooth implant restorations in the esthetic zone of the maxilla: A systematic review.

    Science.gov (United States)

    Arunyanak, Sirikarn P; Pollini, Adrien; Ntounis, Athanasios; Morton, Dean

    2017-07-01

    Esthetic outcomes associated with implant dentistry are important to both clinicians and patients. However, esthetic satisfaction may vary between the 2 groups. In order to evaluate the current publications relating to this topic, the following focused question was developed, "what are the quantitative and qualitative differences between clinician evaluations and patient perspectives in the assessment of single-tooth implant outcomes in the esthetic zone?" The purpose of this systematic review was to identify differences in esthetic satisfaction between clinicians and patients when evaluating single-tooth implant-supported restorations. An electronic search of the Medline database and Cochrane Central Register of Controlled Trials (2000 to 2014) was performed. The search was supplemented by a manual search of specific journals. A quality assessment of full-text articles was performed according to Cochrane Collaboration's tool and Newcastle-Ottawa scale for risk of bias assessment. Information regarding outcomes was collected and compared. The search term combinations identified 555 titles. Subsequent to further review, 11 publications, including 2 randomized controlled trials, were selected for inclusion. Because of the heterogeneity of the study designs, study interventions, and esthetic assessment methods, no meta-analysis was performed. The clinicians identified a satisfactory outcome in 51% to 100% for peri-implant soft tissue and 62% to 90% for implant restorations. Patients showed a mean range score of 43% to 93% for peri-implant soft tissue and 81% to 96% for implant restorations. The visual analog scale score of the dentists was always lower than that of the patients. The review identified correlations between subjective and objective assessments for the Pink Esthetic Score (PES), the Papilla Index (PI), the Implant Crown Aesthetic Index (ICAI), and the modified (mod-ICAI) indices. Clinicians are more critical of esthetic outcomes than patients. The PES and

  6. Objective measurements for grading the nasal esthetics on Basal view in individuals with secondary cleft nasal deformity.

    Science.gov (United States)

    He, Xing; Li, Hua; Shao, Yan; Shi, Bing

    2015-01-01

    The purpose of this study is to ascertain objective nasal measurements from the basal view that are predictive of nasal esthetics in individuals with secondary cleft nasal deformity. Thirty-three patients who had undergone unilateral cleft lip repair were retrospectively reviewed in this study. The degree of nasal deformity was subjectively ranked by seven surgeons using standardized basal-view measurements. Nine physical objective parameters including angles and ratios were measured. Correlations and regressions between these objective and subjective measurements were then analyzed. There was high concordance in subjective measurements by different surgeons (Kendall's harmonious coefficient = W = .825, P = .006). The strongest predictive factors for nasal aesthetics were the ratio of length of nasal alar (r = .370, P = .034) and the degree of deviation of the columnar axis (r = .451, P = .008). The columellar angle had a more powerful effect in rating nasal esthetics. There was reliable concordance in subjective ranking of nasal esthetics by surgeons. Measurement of the columnar angle may serve as an independent, objective predictor of esthetics of the nose.

  7. Autogenous bone grafts in the esthetic zone: optimizing the procedure using piezosurgery.

    Science.gov (United States)

    Majewski, Piotr

    2012-12-01

    Soft and hard tissue defects pose a therapeutic challenge in modern implant dentistry. There are a multitude of surgical techniques available, and it is necessary to match the problem with the solution. This report describes the reconstruction of the alveolar ridge in the esthetic zone with the help of autogenous bone blocks harvested from the chin that were shaped to fit and stabilized at the recipient site. The procedures were performed using Piezosurgery, which made it possible to introduce surgical modifications and had a significant impact on the accuracy of the procedure. An observation period of 2 to 7 years showed positive stable results for treatment in terms of function and esthetics.

  8. Dry sliding wear behaviour of organo-modified montmorillonite filled epoxy nanocomposites using Taguchi's techniques

    International Nuclear Information System (INIS)

    Rashmi; Renukappa, N.M.; Suresha, B.; Devarajaiah, R.M.; Shivakumar, K.N.

    2011-01-01

    Highlights: → Successful fabrication of OMMT filled epoxy nanocomposites by high-shear mixing mehod. → Systematic tribological behaviour of the nanocomposites was made using Taguchi method. → Worn surface morphologies of the samples were discussed for different wear mechanisms. → Generation of wear data for sliding/bearing parts for different industries. -- Abstract: The aim of the research article is to study the dry sliding wear behaviour of epoxy with different wt.% of organo-modified montmorillonite (OMMT) filled nanocomposites. An orthogonal array (L 9 ) was used to investigate the influence of tribological parameters. The results indicate that the sliding distance emerges as the most significant factor affecting wear rate of epoxy nanocomposites. Experimental results showed that the inclusion of 5 wt.% OMMT nanofiller increased the wear resistance of the epoxy nanocomposite significantly. Furthermore, the worn surfaces of the samples were analyzed by scanning electron microscopy (SEM) to study the wear mechanisms and to correlate them with the wear test results.

  9. Aging and service wear of diesel engines used for emergency power at nuclear power stations

    International Nuclear Information System (INIS)

    Dingee, P.A.; Johnson, A.B.

    1985-01-01

    Aging and wear problems associated with emergency standby diesel generators are under study as part of the US Nuclear Regulatory Commission Nuclear Plant Aging Research program. Aging/wear factors identified in this study to date include chemical, mechanical, electrochemical, and bacterial mechanisms. The study also examines the potential of excessive engine testing as a cause of premature wear. To date, the results of this effort are not conclusive. An assessment of current wear mitigation measures such as engine maintenance and surveillance procedures suggests the need for their further development within the nuclear industry

  10. Thin layer activation: measuring wear and corrosion

    International Nuclear Information System (INIS)

    Delvigne, T.; Leyman, D.; Oxorn, K.

    1995-01-01

    The technique known as thin layer activation (TLA) is explained and assessed in this article. Widely used, in for example the automotive industry, TLA allows on-line monitoring of the loss of matter from a critical surface, by wear erosion and corrosion. The technique offers extremely high sensitivity thus leading to reduced test times. On-line wear phenomena can be assessed during operation of a mechanical process, even through thick engine walls. (UK)

  11. Esthetic and Clinical Performance of Implant-Supported All-Ceramic Crowns Made with Prefabricated or CAD/CAM Zirconia Abutments: A Randomized, Multicenter Clinical Trial.

    Science.gov (United States)

    Wittneben, J G; Gavric, J; Belser, U C; Bornstein, M M; Joda, T; Chappuis, V; Sailer, I; Brägger, U

    2017-02-01

    Patients' esthetic expectations are increasing, and the options of the prosthetic pathways are currently evolving. The objective of this randomized multicenter clinical trial was to assess and compare the esthetic outcome and clinical performance of anterior maxillary all-ceramic implant crowns (ICs) based either on prefabricated zirconia abutments veneered with pressed ceramics or on CAD/CAM zirconia abutments veneered with hand buildup technique. The null hypothesis was that there is no statistically significant difference between the 2 groups. Forty implants were inserted in sites 14 to 24 (FDI) in 40 patients in 2 centers, the Universities of Bern and Geneva, Switzerland. After final impression, 20 patients were randomized into group A, restored with a 1-piece screw-retained single crown made of a prefabricated zirconia abutment with pressed ceramic as the veneering material using the cut-back technique, or group B using an individualized CAD/CAM zirconia abutment (CARES abutment; Institut Straumann AG) with a hand buildup technique. At baseline, 6 mo, and 1 y clinical, esthetic and radiographic parameters were assessed. Group A exhibited 1 dropout patient and 1 failure, resulting in a survival rate of 94.7% after 1 y, in comparison to 100% for group B. No other complications occurred. Clinical parameters presented stable and healthy peri-implant soft tissues. Overall, no or only minimal crestal bone changes were observed with a mean DIB (distance from the implant shoulder to the first bone-to-implant contact) of -0.15 mm (group A) and 0.12 mm (group B) at 1 y. There were no significant differences at baseline, 6 mo, and 1 y for DIB values between the 2 groups. Pink esthetic score (PES) and white esthetic score (WES) values at all 3 examinations indicated stability over time for both groups and pleasing esthetic outcomes. Both implant-supported prosthetic pathways represent a valuable treatment option for the restoration of single ICs in the anterior maxilla

  12. Interdisciplinary management for restoration of function and esthetics in a patient with hereditary amelogenesis imperfecta

    Directory of Open Access Journals (Sweden)

    Sushma Dhiman

    2015-01-01

    Full Text Available Amelogenesis imperfecta (AI is a type of the hereditary disorder which is expressed as a group of conditions causing developmental alterations in the structure of enamel. It is associated with a reduction of oral health-related quality-of-life, has an impact on psychological well-being, and leads to various physiological problems. Children or adults with AI express varying degree of malocclusions either in the form of crowding, impacted teeth, spacing, retained teeth, reduced vertical height due to abnormal tooth structure or undue tooth loss. Orthodontic treatment should precede esthetic rehabilitation. Proper diagnosis of the case is quintessential to provide durable functional and esthetic result to these patients, improving the quality of their lives. We present a case of interdisciplinary management for restoring function and esthetics in a patient with hereditary AI of the hypoplastic type accompanied with tooth impaction and some other dental anomalies.

  13. Analysis of the growth poles in esthetic dentistry

    Directory of Open Access Journals (Sweden)

    Andreea Dana Tudose

    2015-05-01

    Full Text Available Growth poles are considered dynamic elements of economic growth, responsible for economical technogical, ideological, spiritual and moral integration.Bioeconomy is currently an area of great and mighty power development. High complexity of this field is to combine the use of technologies that use biological resources in the range of human values involved. This study requires that objective SWOT analysis applied in dental esthetics with strict reference to the quality of work in relation to aesthetic and functional effectiveness of the treatment, the life, the method of reconstruction, working technique, the degree of invasiveness of treatment in relation to conservation dental tissues ,execution costs, costs of resources used in dental anterior segment reconstruction and economic analysis of the modalities of treatment techniques reported the need and level of understanding of patients on treatment aesthetic-functional complexity. As material and method took into account the interaction of four factors: Strenghts-Weaknesses-Opportunities -Hazards. In group “Strengths” we have included successful treatment aesthetic-functional execution moderate cost, short time working on the seat, which shows limited use of natural resources. In group “Weaknesses” I included invasiveness of biological treatment, increased during execution of the work, aesthetic-functional failure , lack of training practitioners in dental aesthetics, lack of existant cabinets to promote interest in aesthetic dental medicine. “Opportunities” referred to the minimally invasive treatment of dental tissue in existing clinical context with predictable results, as higher interest of patients for dental esthetics, raising the standard of care internationally. In group “Risks” (threats I listed: low resistance while works (weak predictability, decreasing purchasing power, changing customer preferences, increase service quality standards. In the second chapter we

  14. A new strategy for wear and corrosion measurements using ion beam based techniques

    International Nuclear Information System (INIS)

    Dudu, D.; Popa, V.; Racolta, P.M.; Voiculescu, Dana

    2001-01-01

    An efficient and precise method for wear testing is Thin Layer Activation (TLA), which is based on the production of a thin layer of radioisotopes in the component surface by bombardment with a charged particle beam. These radioisotopes decay by emitting a characteristic gamma radiation that can be detected with thallium activated sodium iodide NaI(Tl) detectors. Since the material loss due to wear or corrosion is directly proportional to the loss in radioactivity of the activated surface, the wear/corrosion can be monitored in real time. Alternatively, the increase of the activity of the removed material debris collected in an oil bath of engine or in a filter also gives a measure of wear. The application of TLA and UTLA (ultra TLA - by recoil implantation) techniques presupposes establishing the optimum working and measuring conditions for the following steps: irradiation, post irradiation, and 'in situ' measurements. Having in view the diversity of components subjected to wear or corrosion to TLA-based investigations, dedicated beam lines for in-air or vacuum irradiation and translating/rotating target holders were developed by the U-120 Cyclotron of IFIN-HH. The modified IFIN-HH U-120 cyclotron from Bucharest is a classical variable energy machine that can accelerate protons up to 14 MeV, deuterons up to 13.5 MeV, and alpha particles up to 27 MeV. At this machine, TLA has mainly been used for studies of various parts of running machines on test benches such as piston - rings and linear cylinders. Also lubricant characterization studies were conducted here. The main advantage of TLA compared to conventional techniques for wear measurements is its ability to perform continuous in situ wear measurements of engine components, such as cylinder liners and piston rings, without the need to dismantle the components investigated. In addition high wear sensitivity and resolution of wear down to nano meters dimensions is guaranteed. Although the level of activity used in

  15. Esthetic assessment of immediately restored implants combined with GBR and free connective tissue graft.

    Science.gov (United States)

    Kolerman, Roni; Nissan, Joseph; Mijiritsky, Eitan; Hamoudi, Nasreen; Mangano, Carlo; Tal, Haim

    2016-11-01

    Esthetic assessment of immediately restored implants combined with GBR and free connective tissue (CT) graft METHODS: A case-control, retrospective study involving 34 patients treated with maxillary anterior single implants, immediately placed and restored. Clinical and esthetic results were analyzed using standard clinical examination and a comprehensive index, comprising pink esthetic and white esthetic scores (PES/WES). The height of the implant crown and the corresponding height of the contralateral tooth crown were measured to identify mucosal recessions. The distance from the mucosal margin to the implant shoulder (DIM) was measured on the master model. Thirty of 34 implants fulfilled the strict success criteria set for dental implants with regard to osseointegration. Success was defined as implants with bone loss not exceeding 1.5 mm during the first year and loosing not more than 0.2 for each successive year. The other four implants were stable but did not meet the bone loss criteria mentioned above and defined as survived implants. Mean PES/WES was 14.44 ± 2.34 (range: 9-20). Mean PES was 7.12 ± 1.89 (range: 1-10). The highest mean values were achieved for the variable of root convexity/soft tissue color and texture (1.71 ± 0.46) whereas the mesial papilla (1.09 ± 0.62) proved to be the least pleasing. The mean WES was 7.32 ± 1.25 (range: 5-10). The difference between IC and contralateral TC was 0.54 mm. The mean value for the facial DIM was 3.82 ± 0.87 mm. An evaluation of soft and hard tissue augmentation in immediately restored immediate implant procedures was employed to obtain stable hard and soft tissues. The combined GBR and CT graft procedure achieved favorable peri-implant soft tissue condition and esthetic results. However, recession and incomplete papillas were frequently observed. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Friction measurement in a hip wear simulator.

    Science.gov (United States)

    Saikko, Vesa

    2016-05-01

    A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown to sense only a minor part of the total frictional torque. With the present method, the total frictional torque of the prosthetic hip was measured. This was shown to consist of the torques about the vertical axis above the joint and about the leaning axis. Femoral heads made from different materials were run against conventional and crosslinked polyethylene acetabular cups in serum lubrication. Regarding the femoral head material and the type of polyethylene, there were no categorical differences in frictional torque with the exception of zirconia heads, with which the lowest values were obtained. Diamond-like carbon coating of the CoCr femoral head did not reduce friction. The friction factor was found to always decrease with increasing load. High wear could increase the frictional torque by 75%. With the present system, friction can be continuously recorded during long wear tests, so the effect of wear on friction with different prosthetic hips can be evaluated. © IMechE 2016.

  17. Consideration of wear rates at high velocity

    Science.gov (United States)

    Hale, Chad S.

    The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models

  18. Immediate Single-Tooth Implant Placement in Bony Defects in the Esthetic Zone : A 1-Year Randomized Controlled Trial

    NARCIS (Netherlands)

    Slagter, Kirsten W.; Meijer, Henny J. A.; Bakker, Nicolaas A.; Vissink, Arjan; Raghoebar, Gerry M.

    Background: This study aims to assess, with regard to marginal bone level (MBL), whether the outcome of immediate implant placement in bony defects in the esthetic zone was non-inferior to delayed implant placement after 1 year. Methods: Forty patients with a failing tooth in the esthetic zone and a

  19. Development of friction and wear full-scale testing for TKR prostheses with reliable low cost apparatus

    Science.gov (United States)

    Suwandi, Agri; Soemardi, Tresna P.; Kiswanto, Gandjar; Kusumaningsih, Widjajalaksmi; I. Gusti Agung I. G., W.

    2018-02-01

    Prostheses products must undergo simulation and physical testing, before clinical testing. Finite element method is a preliminary simulation for in vivo test. The method visualizes the magnitude of the compressive force and the critical location of the Total Knee Replacement (TKR) prostheses design. In vitro testing is classified as physical testing for prostheses product. The test is conducted to evaluate the potential failure of the product and the characteristics of the prostheses TKR material. Friction and wear testing are part of the in vivo test. Motion of knee joints, which results in the phenomena of extension and deflection in the femoral and tibia insert, is represented by friction and wear testing. Friction and wear tests aim to obtain an approximate lifetime in normal and extreme load patterns as characterized by the shape of the friction surface area. The lifetime estimation requires friction and wear full-scale testing equipments for TKR prostheses products. These are necessary in obtaining initial data on potential product failures and characterizing of the material based on the ASTM F2724-08 standards. Based on the testing result and statistical analysis data, the average wear rate value per year is 2.19 × 10-3 mg/MC, with a 10 % safety limit of volume and 14,400 cycles times, for 15 hours moving nonstop then the prediction of wear life of the component tibia insert is ± 10 years.

  20. Infrared spectroscopy, nano-mechanical properties, and scratch resistance of esthetic orthodontic coated archwires.

    Science.gov (United States)

    da Silva, Dayanne Lopes; Santos, Emanuel; Camargo, Sérgio de Souza; Ruellas, Antônio Carlos de Oliveira

    2015-09-01

    To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires. The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test. The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm(-1). The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches. The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.

  1. Rapid Analyses of Polyetheretherketone Wear Characteristics by Accelerated Wear Testing with Microfabricated Surfaces for Artificial Joint Systems.

    Science.gov (United States)

    Su, Chen-Ying; Kuo, Chien-Wei; Fang, Hsu-Wei

    2017-01-01

    Wear particle-induced biological responses are the major factors resulting in the loosening and then failure of total joint arthroplasties. It is feasible to improve the lubrication and reduce the wear of artificial joint system. Polyetheretherketone (PEEK) is considered as a potential bearing material due to its mechanical characteristics of resistance to fatigue strain. The PEEK wear particles have been indicated to be involved in biological responses in vitro, and further studies regarding the wear phenomena and wear particle generation are needed. In this study, we have established an accelerated wear testing system with microfabricated surfaces. Various contact pressures and lubricants have been utilized in the accelerated wear tests. Our results showed that increasing contact pressure resulted in an increase of wear particle sizes and wear rate, and the size of PEEK wear particles can be controlled by the feature size of microfabricated surfaces. These results provided the information rapidly about factors that affect the morphology and amount of PEEK wear particles and can be applied in the future for application of PEEK on the biological articulation system.

  2. Minimal guided bone regeneration procedure for immediate implant placement in the esthetic zone

    Directory of Open Access Journals (Sweden)

    Nettemu Sunil Kumar

    2013-01-01

    Full Text Available The anterior maxilla presents a challenging milieu interior for ideal placement of implants because of the compromised bone quality. With the advent of intraoral bone harvesting and augmentation techniques, immediate implant placement into fresh extraction sockets have become more predictable. Immediate implant placement has numerous advantages compared to the delayed procedure including superior esthetic and functional outcomes, maintenance of soft and hard tissue integrity and increased patient compliance. This case report exhibits immediate implant placement in the maxillary esthetic zone by combining a minimal invasive autogenous block bone graft harvest technique for ensuring successful osseointegration of the implant at the extraction site.

  3. Covering the screw-access holes of implant restorations in the esthetic zone: a clinical report.

    Directory of Open Access Journals (Sweden)

    Abolfazl Saboury

    2014-12-01

    Full Text Available Screw-retained implant restorations have an advantage of predictable retention as well as retrievability, and obviate the risk of excessive sub-gingival cement commonly associated with cement retained implant restorations. Screw-retained restorations generally have screw access holes, which can compromise esthetics and weaken the porcelain around the holes. The purpose of this study is to describe the use of a separate overcasting crown design to cover the screw access hole of implant screw-retained prosthesis for improved esthetics.

  4. Esthetic impact of gingival plastic surgery from the dentistry students’ perspective

    Science.gov (United States)

    Ayyildiz, Erdem; Tan, Enes; Keklik, Hakan; Demirtag, Zulfikar; Celebi, Ahmet Arif; Pithon, Matheus Melo

    2016-01-01

    Objective: The aim of the this study was to evaluate the perception of smile esthetics and alterations in cases of gingival plastic surgery for correction of a gummy smile, by means of alterations in smile photograph among dentistry degree students. Materials and Methods: A frontal smile photograph of a 40-year-old woman having normal occlusion was used with diverse compositions of gingival exposure level and crown length of maxillary teeth. The eight photographs were evaluated by 216 dentistry students in five class groups (1st, 2nd, 3rd, 4th and 5th classes). Results: The results revealed that almost all of the class’ students perceived differences between images, additionally, the highest percentage of students that answered “no difference” was 12% at 1st class’ students. 1st and 2nd class’ students most liked photograph which is 2.5 mm gingival display and 3rd class students liked two different photographs which are 2.5 mm gingival display and 2 mm gingival display whereas 4th class students preferred two different photographs which are 1.5 mm gingival display and 1 mm gingival display, 5th class students preferred photograph which is 1.5 mm gingival display as the most. Conclusion: Esthetic perception of smile improve as a student passes to higher study classes in terms of gingival exposure. The harmonious display of gingiva exhibits an important effect in the smile esthetics rather than reduced or excessive display. PMID:27403061

  5. Esthetic smile rehabilitation of anterior teeth by treatment with biomimetic restorative materials: a case report

    Directory of Open Access Journals (Sweden)

    Gouveia TH

    2017-05-01

    Full Text Available Thayla Hellen Nunes Gouveia, Jéssica Dias Theobaldo, Waldemir Francisco Vieira-Junior, Débora Alves Nunes Leite Lima, Flávio Henrique Baggio Aguiar Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Campinas, SP, Brazil Background: In daily clinical practice, esthetics of anterior teeth is a common presenting complaint of patients.Objective: This case report discusses the management of asymmetric smile associated with unsatisfactory extensive composite restorations and describes a clinical protocol using the direct composite resin for smile enhancement to restore the dental harmony of anterior teeth.Methods: The treatment planning was based on a diagnostic wax-up and cosmetic mock-up. After clinical and patient approvals were obtained, the patient was subjected to direct and indirect restorative treatment.Conclusion: Nanocomposites are an effective alternative for anterior teeth restorations. Additionally, good planning enables satisfactory esthetic results, leading to the correction of an inappropriate axial inclination of incisors. Keywords: composite, adhesive, smile, esthetic, restoration

  6. Effect of oxidation on the wear behavior of a ZrN coating

    Energy Technology Data Exchange (ETDEWEB)

    Atar, E. [Gebze Inst. of Tech., Material Science and Engineering Dept., Kocaeli (Turkey); Cimenoglu, H.; Kayali, E.S. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Engineering, Azazaga, Istanbul (Turkey)

    2005-07-01

    In the present study tribological performance of ZrN coatings deposited on hardened AISI D2 quality cold work tool steel by arc-physical vapor deposition technique has been examined in as-deposited and oxidized conditions. ZrN coatings were oxidized at 400 C for various times up to 12 h. Reciprocating wear tests carried out by rubbing Al{sub 2}O{sub 3} balls on the coatings, revealed significant improvement in wear resistance of ZrN coating upon oxidation. Oxidation treatment at 400 C for 12 h yielded seven times higher wear resistance than as-deposited ZrN coating, beside significant reduction in the wear of counterface (Al{sub 2}O{sub 3} ball). (orig.)

  7. Effect of oxidation on the wear behavior of a ZrN coating

    International Nuclear Information System (INIS)

    Atar, E.; Cimenoglu, H.; Kayali, E.S.

    2005-01-01

    In the present study tribological performance of ZrN coatings deposited on hardened AISI D2 quality cold work tool steel by arc-physical vapor deposition technique has been examined in as-deposited and oxidized conditions. ZrN coatings were oxidized at 400 C for various times up to 12 h. Reciprocating wear tests carried out by rubbing Al 2 O 3 balls on the coatings, revealed significant improvement in wear resistance of ZrN coating upon oxidation. Oxidation treatment at 400 C for 12 h yielded seven times higher wear resistance than as-deposited ZrN coating, beside significant reduction in the wear of counterface (Al 2 O 3 ball). (orig.)

  8. Sliding Wear and Fretting Wear of DLC-Based, Functionally Graded Nanocomposite Coatings

    Science.gov (United States)

    Miyoshi, K.; Pohlchuck, B.; Street, Kenneth W.; Zabinski, J. S.; Sanders, J. H.; Voevodin, A. a.; Wu, R. L. C.

    1999-01-01

    Improving the tribological functionality of diamondlike carbon (DLC) films--developing, good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbon-diamondlike carbon (Ti-Ti(sub x) C(sub y)-DLC) underlayer were produced on AISI 440C stainless steel substrates by the hybrid technique of magnetron sputtering and pulsed-laser deposition. The resultant DLC films were characterized by Raman spectroscopy, scanning electron microscopy, and surface profilometry. Two types of wear experiment were conducted in this investioation: sliding friction experiments and fretting wear experiments. Unidirectional ball-on-disk sliding friction experiments were conducted to examine the wear behavior of an a-DLC/Ti-Ti(sub x) C(sub y)-DLC-coated AISI 440C stainless steel disk in sliding contact with a 6-mm-diameter AISI 440C stainless steel ball in ultrahigh vacuum, dry nitrogen, and humid air. Although the wear rates for both the coating and ball were low in all three environments, the humid air and dry nitrogen caused mild wear with burnishing, in the a-DLC top layer, and the ultrahigh vacuum caused relatively severe wear with brittle fracture in both the a-DLC top layer and the Ti-Ti(sub x) C(sub y)-DLC underlayer. For reference, amorphous hydrogenated carbon (H-DLC) films produced on a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coatings by using an ion beam were also examined in the same manner. The H-DLC films markedly reduced friction even in ultrahigh vacuum without sacrificing wear resistance. The H-DLC films behaved much like the a-DLC/Ti-Ti(sub x) C(sub y)-DLC nanocomposite coating in dry nitrogen and humid air, presenting low friction and low wear. Fretting wear experiments were conducted in humid air (approximately 50% relative humidity) at a frequency of 80 Hz and an amplitude of 75 micron on an a

  9. Wear calculation possibility of slide-friction pair "shaft-plain bearing" for four-stroke engines

    Science.gov (United States)

    Springis, Guntis; Rudzitis, Janis; Avisane, Anita; Kumermanis, Maris

    2013-12-01

    The issues of the service life and its prediction for main four stroke engine parts such as shaft-plain bearing have always been of particular importance. The article determines the most suitable mathematical calculation model allowing considering the set of parameters needed for the slide-friction pair's calculation, thus achieving a result as precise as possible. Since the wear process is variable and many-sided it is influenced by very many different parameters, for example, the surface geometry (roughness, waviness, form deviation, etc.), the physical and mechanical conditions of the upper layer, component material, wear regime, wear temperature, etc. The offered wear calculation model taking into consideration as much as possible wear affecting parameters is based on the fatigue theory regularities of the friction surface's destroying, using the approach of probability theory.

  10. Wearing ambidextrous vinyl gloves does not impair manual dexterity.

    Science.gov (United States)

    Drabek, Tomas; Boucek, Charles D; Buffington, Charles W

    2013-01-01

    Universal precautions mandate that health care workers wear gloves to prevent the unintended spread of bloodborne pathogens. Gloves may affect manual dexterity, generally delaying task completion. Our previous study showed that wearing the wrong size latex surgical glove degraded manual dexterity. The use of non-sterile and non-latex gloves may limit certain risks and be more cost-effective. However, such gloves may produce different results. We hypothesized that ambidextrous vinyl examination gloves would degrade manual dexterity compared with bare hands. We studied 20 random subjects from a medical environment. Subjects performed a standard battery of Grooved Pegboard tasks while bare-handed, wearing ambidextrous non-sterile vinyl gloves that were their preferred size, a size too small, and a size too large. The order was randomized with a Latin Square design to minimize the effects of time, boredom, and fatigue on the subjects. Subjects were also invited to comment on the fit of different size gloves. Wearing vinyl gloves of both the preferred size and a size up or down failed to affect manual dexterity vs. bare hands on time to insert pegs, and pegs dropped during insertion or removal. In contrast, the time to remove pegs was reduced by wearing preferred size vinyl gloves compared with performing the task with bare hands (Pgloves that were too small caused significant hand discomfort. Vinyl gloves surprisingly do not degrade manual dexterity even when worn in ill-fitting sizes. Wearing a preferred size vinyl glove vs. bare hands may improve dexterity in selected tasks. Choosing a comfortable, large size seems the best strategy when the preferred size is unavailable. Thinner vinyl gloves may improve grip and may not degrade touch as much as latex surgical gloves and may thus represent a reasonable choice for selected tasks.

  11. The influence of nominal stress on wear factors of carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA® Wear Performance) against zirconia toughened alumina (Biolox® delta ceramic).

    Science.gov (United States)

    Evans, Andrew; Horton, Henrietta; Unsworth, Anthony; Briscoe, Adam

    2014-06-01

    Carbon fibre-reinforced polyetheretherketone is an attractive alternative to ultra-high-molecular-weight polyethylene in artificial joints, but little has been published on the influence of stress on the wear factor. We know that in ultra-high-molecular-weight polyethylene, the wear factor reduces as the normal stress increases, which is counter-intuitive but very helpful in the case of non-conforming contacts. In this study, carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA ® Wear Performance) has been investigated in a pin-on-plate machine under steady loads and under stresses typical of hip and knee joints. At stresses below about 6 MPa, wear factors are between 10 and a 100 times lower than for ultra-high-molecular-weight polyethylene but at higher stresses the wear factors increase substantially. © IMechE 2014.

  12. Pediatricians Working Part-Time Has Plateaued.

    Science.gov (United States)

    Cull, William L; Frintner, Mary Pat; O'Connor, Karen G; Olson, Lynn M

    2016-04-01

    To examine trends in pediatricians working part-time and residents seeking part-time work and to examine associated characteristics. The American Academy of Pediatrics (AAP) Periodic Survey of Fellows and the AAP Annual Survey of Graduating Residents were used to examine part-time employment. Fourteen periodic surveys were combined with an overall response rate of 57%. Part-time percentages were compared for surveys conducted from 2006-2009 and 2010-2013. The AAP Annual Surveys of Graduating Residents (combined response rate = 60%) from 2006-2009 were compared with 2010-2013 surveys for residents seeking and obtaining part-time positions following training. Multivariable logistic regression models identified characteristics associated with part-time work. Comparable percentages of pediatricians worked part-time in 2006-2009 (23%) and 2010-2013 (23%). There was similarly no statistically significant difference in residents seeking part-time work (30%-28%), and there was a slight decline in residents accepting part-time work (16%-13%, aOR .75, 95% CI .56-.96). Increases in working part-time were not found for any subgroups examined. Women consistently were more likely than men to work part-time (35% vs 9%), but they showed different patterns of part-time work across age. Women in their 40s (40%) were more likely than other women (33%) and men in their 60s (20%) were more likely than other men (5%) to work part-time. There has been a levelling off in the number of pediatricians working part-time and residents seeking part-time work. Overall, women remain more likely to work part-time, although 1 in 5 men over 60 work part-time. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Testing of a Fiber Optic Wear, Erosion and Regression Sensor

    Science.gov (United States)

    Korman, Valentin; Polzin, Kurt A.

    2011-01-01

    The nature of the physical processes and harsh environments associated with erosion and wear in propulsion environments makes their measurement and real-time rate quantification difficult. A fiber optic sensor capable of determining the wear (regression, erosion, ablation) associated with these environments has been developed and tested in a number of different applications to validate the technique. The sensor consists of two fiber optics that have differing attenuation coefficients and transmit light to detectors. The ratio of the two measured intensities can be correlated to the lengths of the fiber optic lines, and if the fibers and the host parent material in which they are embedded wear at the same rate the remaining length of fiber provides a real-time measure of the wear process. Testing in several disparate situations has been performed, with the data exhibiting excellent qualitative agreement with the theoretical description of the process and when a separate calibrated regression measurement is available good quantitative agreement is obtained as well. The light collected by the fibers can also be used to optically obtain the spectra and measure the internal temperature of the wear layer.

  14. Wear analysis of disc cutters of full face rock tunnel boring machine

    Science.gov (United States)

    Zhang, Zhaohuang; Meng, Liang; Sun, Fei

    2014-11-01

    Wear is a major factor of disc cutters' failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians' experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters' life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.

  15. A Study on Corrosion and Fretting Wear Resistance of Alloy 690 Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Won, Ju Jin; Min, Su Jung; Kim, Myeong Su; Kim, Kyu Tae [Dongguk Univ., Gyeongju (Korea, Republic of)

    2013-10-15

    In this article, the effects of such failures have on the materials of alloy 690 are assessed. The corroded volume variation and mass decreased continuously with time. However, the oxide volume changes in an irregular pattern since the oxide formed on the alloy 690 metal may be detached due to the flake formation. The amount of the fretting wear increased with time. It can be seen that the wear rate increased with time and reduced at the later time. The test results show that the ductility decreased as corrosion increases. Alloy 690 is broadly used as a material of nuclear power plant's steam generator tubes because of its excellent mechanical strength, corrosion properties, wear properties and stability at a high temperature. However, the tubes for nuclear power plant's steam generators become a major threat for lifetime management and efficient operation of nuclear power plant due to various corrosion and fretting wear failures caused by flow-induced vibration (FIV) that occurs between tubes.

  16. Patient satisfaction with single-tooth implant therapy in the esthetic zone

    NARCIS (Netherlands)

    den Hartog, Laurens; Meijer, Henny J. A.; Santing, Hendrik J.; Vissink, Arjan; Raghoebar, Gerry M.

    2014-01-01

    This prospective study assessed patient satisfaction before and after single-tooth implant therapy in the esthetic zone. Before implant therapy, patients wore an acrylic resin tissue-supported removable partial denture (RPD). A total of 153 patients were included. Self-administered questionnaires

  17. The Effect of Subepithelial Connective Tissue Graft Placement on Esthetic Outcomes After Immediate Implant Placement: Systematic Review.

    Science.gov (United States)

    Lee, Chun-Teh; Tao, Chih-Yun; Stoupel, Janet

    2016-02-01

    Immediate implantation, despite many advantages, carries a risk of gingival recession, papilla loss, collapse of ridge contour, and other esthetic complications. Soft tissue graft placement combined with immediate implantation may be used to reduce these concerns. This review aims to systematically analyze clinical esthetic outcomes of the immediate implant combined with soft tissue graft (IMITG). The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews were used. The electronic search was conducted using MEDLINE (PubMed), EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) from January 1980 to October 2014. Quality assessments of selected articles were performed. Mid-buccal gingival level, interproximal gingival level, facial gingival thickness, gingival ridge dimension, and width of keratinized gingiva were the esthetic outcomes reviewed. Weighted mean difference of mid-buccal gingival level (WDBGL), papilla index score (WDPIS), and width of keratinized gingiva (WDKG) between initial and last measurements were calculated. Other esthetic outcomes were assessed by the descriptive analysis. Ten studies with a minimum of 6-month follow-up were included, and reported esthetic outcomes were analyzed. Mid-buccal gingival level (WDBGL, 0.07 mm; 95% confidence interval [CI] = -0.44 to 0.59; P = 0.12) and interproximal gingival level did not significantly change after IMITG (WDPIS in the mesial site, 0.31; 95% CI = -0.01 to 0.64; P = 0.06; and WDPIS in the distal site, 0.29; 95% CI = -0.06 to 0.65; P = 0.11). Width of keratinized gingiva significantly increased after IMITG (WDKG, 1.27 mm; 95% CI = -0.08 to 2.46; P = 0.04). Facial gingival thickness and gingival ridge dimension could be increased after IMITG. Because of the heterogeneity and limited number of selected studies, no conclusive statement could be made regarding the benefit of IMITG on esthetic outcomes. More randomized controlled trials

  18. Psychological well-being, dental esthetics, and psychosocial impacts in adolescent orthodontic patients: A prospective longitudinal study.

    Science.gov (United States)

    Deng, Xiao; Wang, Yun-Ji; Deng, Feng; Liu, Pang-Li; Wu, Yan

    2018-01-01

    We examined the role of adolescent orthodontic patients' psychological well-being attributes (self-esteem, general body image, and positive and negative affects) and the clinical indicators of dental esthetics (orthodontists' ratings on the Index of Orthodontic Treatment Need-Aesthetic Component [IOTN-AC]), and their changes from pretreatment to posttreatment as predictors of the psychosocial impact of dental esthetics. In this prospective longitudinal study, 1090 adolescent orthodontic patients seeking treatment at the Stomatological Hospital of Chongqing Medical University in China (mean age, 14.25 years; SD, 2.03 years) were assessed before treatment, and 68.99% (n = 752) were assessed after treatment. All subjects completed a questionnaire measuring psychological well-being attributes and 3 components of the Psychosocial Impact of Dental Aesthetics (perceptive, cognitive-affective, and social-functional). Clinical indicators of dental esthetics were measured by 3 orthodontists using the IOTN-AC. Substantial enhancement from pretreatment to posttreatment was found in all 3 Psychosocial Impacts of Dental Aesthetics components, confirming the positive effects of orthodontic treatment on oral health-related quality of life. Psychosocial impact of dental esthetics at baseline and improvement from pretreatment to posttreatment were found to be predicted by the patients' psychological well-being attributes (self-esteem, general body image, and negative affect) and the clinical indicators (orthodontists' rating on the IOTN-AC) at baseline, as well as their pretreatment to posttreatment change. Psychological well-being attributes had comparable or greater contribution to the Psychosocial Impact of Dental Aesthetics at baseline as well as greater improvement after treatment than the clinical indicators. These biopsychological models explained 29% to 43% of the variances in psychosocial impacts of dental esthetics outcome at baseline and about 33% of the variance in

  19. Immediate versus Delayed Treatment in the Anterior Maxilla Using Single Implants with a Laser-Microtextured Collar: 3-Year Results of a Case Series on Hard- and Soft-Tissue Response and Esthetics.

    Science.gov (United States)

    Guarnieri, Renzo; Belleggia, Fabrizio; Grande, Maurizio

    2016-02-01

    To compare peri-implant marginal bone loss, soft tissue response, and esthetics following single immediate implant treatment (IIT) and delayed implant treatment (DIT) in the esthetic zone of the maxilla in well-selected patients. Adequate bone volume and ideal soft tissue level/contour were considered requirements for implant therapy, with additional prerequisites for IIT of residual alveolar bone wall integrity and a thick gingival biotype. IIT included immediate placement and provisionalization, while DIT included extraction socket preservation followed by implant placement and provisionalization 4 months later. Cortical bone levels and peri-implant mucosal conditions were evaluated at regular intervals. The esthetic outcome was objectively rated after 3 years using the pink esthetic score (PES) and white esthetic score (WES). Twelve patients received an immediate Laser-Lok® implant, and 13 patients received a delayed Laser-Lok® implant. No significant differences were found between the study groups regarding survival rate (100%). The mean bone level from the implant/abutment interface was 0.35 ± 0.18 mm for IIT and 0.42 ± 0.21 mm for DIT after 3 years (p > 0.05). Mesial and distal papillae remained stable over time in DIT. A tendency for regrowth of mesial and distal papillae was found following IIT (p esthetics, DIT and IIT with single Laser-Lok® implants in the anterior maxilla are comparable and predictable options for well-selected patients. © 2015 by the American College of Prosthodontists.

  20. Objective assessment of the contribution of dental esthetics and facial attractiveness in men via eye tracking.

    Science.gov (United States)

    Baker, Robin S; Fields, Henry W; Beck, F Michael; Firestone, Allen R; Rosenstiel, Stephen F

    2018-04-01

    Recently, greater emphasis has been placed on smile esthetics in dentistry. Eye tracking has been used to objectively evaluate attention to the dentition (mouth) in female models with different levels of dental esthetics quantified by the aesthetic component of the Index of Orthodontic Treatment Need (IOTN). This has not been accomplished in men. Our objective was to determine the visual attention to the mouth in men with different levels of dental esthetics (IOTN levels) and background facial attractiveness, for both male and female raters, using eye tracking. Facial images of men rated as unattractive, average, and attractive were digitally manipulated and paired with validated oral images, IOTN levels 1 (no treatment need), 7 (borderline treatment need), and 10 (definite treatment need). Sixty-four raters meeting the inclusion criteria were included in the data analysis. Each rater was calibrated in the eye tracker and randomly viewed the composite images for 3 seconds, twice for reliability. Reliability was good or excellent (intraclass correlation coefficients, 0.6-0.9). Significant interactions were observed with factorial repeated-measures analysis of variance and the Tukey-Kramer method for density and duration of fixations in the interactions of model facial attractiveness by area of the face (P models was eye, mouth, and nose, but for men of average attractiveness, it was mouth, eye, and nose. For dental esthetics by area, at IOTN 7, the mouth had significantly more visual attention than it did at IOTN 1 and significantly more than the nose. At IOTN 10, the mouth received significantly more attention than at IOTN 7 and surpassed the nose and eye. These findings were irrespective of facial attractiveness levels. For rater sex by area in visual density, women showed significantly more attention to the eyes than did men, and only men showed significantly more attention to the mouth over the nose. Visual attention to the mouth was the greatest in men of

  1. Standard test method for ranking resistance of plastics to sliding wear using block-on-ring wear test—cumulative wear method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of plastics to sliding wear. The test utilizes a block-on-ring friction and wear testing machine to rank plastics according to their sliding wear characteristics against metals or other solids. 1.2 An important attribute of this test is that it is very flexible. Any material that can be fabricated into, or applied to, blocks and rings can be tested. Thus, the potential materials combinations are endless. In addition, the test can be run with different gaseous atmospheres and elevated temperatures, as desired, to simulate service conditions. 1.3 Wear test results are reported as the volume loss in cubic millimetres for the block and ring. Materials of higher wear resistance will have lower volume loss. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with it...

  2. Esthetics with prosthetics in case of maxillary canine transposition: A ...

    African Journals Online (AJOL)

    Esthetics with prosthetics in case of maxillary canine transposition: A clinical report. ... provides a helpful Frequently Asked Questions about PDFs. Alternatively, you can download the PDF file directly to your computer, from where it can be opened using a PDF reader. To download the PDF, click the Download link above.

  3. A guide for recording esthetic and biologic changes with photographs

    Science.gov (United States)

    Arthur W. Magill; R.H. Twiss

    1965-01-01

    Photography has long been a useful tool for recording and analyzing environmental conditions. Permanent camera points can be established to help detect ,and analyze changes in the esthetics and ecology of wildland resources. This note describes the usefulness of permanent camera points and outlines procedures for establishing points and recording data.

  4. Guidelines for patient-specific jawline definition with titanium implants in esthetic, deformity, and malformation surgery.

    Science.gov (United States)

    Mommaerts, Maurice Yves

    2016-01-01

    Asymmetry and unfavorable esthetics of the jawline have become possible to correct in three dimensions using computer aided design and computer aided manufacturing. The aim of this study was to provide esthetic, technical, and operative guidelines for mandibular angle and border augmentation using patient-specific titanium implants made by selective laser melting. University hospital - prospective registry. Twelve patients and 17 implantation sites were documented and prospectively registered. Malformational, deformational, and purely esthetic indications were encountered. Descriptive. Patient satisfaction was high, probably because the patients had input into the planned dimensions and shape. A serious infection with implant removal occurred in one patient who had six previous surgeries at the same sites. Technical and surgical guidelines were developed including splitting implants into two segments when the mental nerve was at risk, using a three-dimensional (3D) puzzle connection, providing at least two screw holes per segment, using scaffolds at the bony contact side, using a "satin" finish at the periosteal side, referring to anatomical structures where possible, making provisions for transbuccal and transoral fixation, using a high vestibular incision, and using a double-layer closure. Esthetic guidelines are discussed but could not be upgraded. Mirroring techniques and 3D print accuracy up to 0.1 mm allow precise planning of jaw angle implants. Patients are pleased when given preoperative renderings for their consideration. Infections can be managed using technical and operative recommendations and careful patient selection.

  5. Facial and occlusal esthetic improvements of an adult skeletal Class III malocclusion using surgical, orthodontic, and implant treatment

    Science.gov (United States)

    de Almeida Cardoso, Mauricio; de Avila, Erica Dorigatti; Guedes, Fabio Pinto; Battilani Filho, Valter Antonio Ban; Capelozza Filho, Leopoldino; Correa, Marcio Aurelio; Nary Filho, Hugo

    2016-01-01

    The aim of this clinical report is to describe the complex treatment of an adult Class III malocclusion patient who was disappointed with the outcome of a previous oral rehabilitation. Interdisciplinary treatment planning was performed with a primary indication for implant removal because of marginal bone loss and gingival recession, followed by orthodontic and surgical procedures to correct the esthetics and skeletal malocclusion. The comprehensive treatment approach included: (1) implant removal in the area of the central incisors; (2) combined orthodontic decompensation with mesial displacement and forced extrusion of the lateral incisors; (3) extraction of the lateral incisors and placement of new implants corresponding to the central incisors, which received provisional crowns; (4) orthognathic surgery for maxillary advancement to improve occlusal and facial relationships; and finally, (5) orthodontic refinement followed by definitive prosthetic rehabilitation of the maxillary central incisors and reshaping of the adjacent teeth. At the three-year follow-up, clinical and radiographic examinations showed successful replacement of the central incisors and improved skeletal and esthetic appearances. Moreover, a Class II molar relationship was obtained with an ideal overbite, overjet, and intercuspation. In conclusion, we report the successful esthetic anterior rehabilitation of a complex case in which interdisciplinary treatment planning improved facial harmony, provided gingival architecture with sufficient width and thickness, and improved smile esthetics, resulting in enhanced patient comfort and satisfaction. This clinical case report might be useful to improve facial esthetics and occlusion in patients with dentoalveolar and skeletal defects. PMID:26877982

  6. Laser engineered net shaping of quasi-continuous network microstructural TiB reinforced titanium matrix bulk composites: Microstructure and wear performance

    Science.gov (United States)

    Hu, Yingbin; Ning, Fuda; Wang, Hui; Cong, Weilong; Zhao, Bo

    2018-02-01

    Titanium (Ti) and its alloys have been successfully applied to the aeronautical and biomedical industries. However, their poor tribological properties restrict their fields of applications under severe wear conditions. Facing to these challenges, this study investigated TiB reinforced Ti matrix composites (TiB-TMCs), fabricated by in-situ laser engineered net shaping (LENS) process, through analyzing parts quality, microstructure formation mechanisms, microstructure characterizations, and workpiece wear performance. At high B content areas (original B particle locations), reaction between Ti and B particles took place, generating flower-like microstructure. At low B content areas, eutectic TiB nanofibers contacted with each other with the formation of crosslinking microstructure. The crosslinking microstructural TiB aggregated and connected at the boundaries of Ti grains, forming a three-dimensional quasi-continuous network microstructure. The results show that compared with commercially pure Ti bulk parts, the TiB-TMCs exhibited superior wear performance (i.e. indentation wear resistance and friction wear resistance) due to the present of TiB reinforcement and the innovative microstructures formed inside TiB-TMCs. In addition, the qualities of the fabricated parts were improved with fewer interior defects by optimizing laser power, thus rendering better wear performance.

  7. The impact of tool wear on the functionality of replicated polymer surface with micro structures

    DEFF Research Database (Denmark)

    Li, Dongya; Zhang, Yang; Regi, Francesco

    Wear happened frequently in the tooling process of mold for polymer production. The scope of this paper is to understand how the wear of the milling tool affected the function of the replicated polymer surface. This study is part of the process chain of fabrication of optical functional surfaces ...

  8. Evaluation of late effects, esthetic results and quality of life after conservative treatment of breast cancer?

    International Nuclear Information System (INIS)

    Geffrelot, J.; Toudic-Emily, F.; Delozier, T.; Switsers, O.; Allouache, D.; Delcambre, C.; Segura, C.; Levy, C.; Dupont, M.; Joly, F.

    2009-01-01

    Purpose: to evaluate the delayed toxicity of two patterns of adjuvant radiotherapy including a breast irradiation, at the dose of 48 Gy in 20 seances and five weeks or 57.60 Gy in 24 seances and six weeks in case of majored factors of local recurrence risk. The secondary objective were the auto evaluation by the patient of the esthetic result and the influence of this last one on the quality of life. Conclusion: the delayed toxicity was dominated by the fibrosis low to moderated one, without any significant difference between the doses of 48 Gy and 57.60 Gy. The esthetic result evaluated by the patient, globally good, seemed however, damaged with the last pattern. A bad esthetic result, without affected the global quality of life was associated to more specific breast symptoms and damaged the perception of the body image. (N.C.)

  9. Assessment of thermal spray coatings for wear and abrasion resistance applications

    Science.gov (United States)

    Karode, Ishaan Nitin

    Thermal spray cermet and metallic coatings are extensively used for wear, abrasion and corrosion control in a variety of industries. The first part of the thesis focuses mainly on testing of sand erosion resistance of thermal spray coatings on carbon composites used in the manufacture of helicopter rotor blades. The test set-up employed is a sand blasting machine and is an effort to duplicate the in-flight conditions especially those encountered in hot arid conditions. The technique adopted follows the Department of Defence test method standard. Carbon Composites have excellent stiffness, strength and low weight/density. The strength to weight ratio is high. Hence, these are used in aerospace applications to a large extent. However, the biggest problem encountered with carbon composites is its low abrasion resistance as its surface is very weak. Hence, thermal spray coatings are used to improve the surface properties of CFRP. Zinc bond coats and WC-Co coatings were tested. However, high amount of thermal stresses were developed between the substrate and the coating due to large differences in the CTE's of the both, leading to high mass losses within two minutes and just 130 grams of sand sprayed on to the coatings with the sand blasting machine built; and hence the coatings with CC as a substrate could not qualify for the application. The second part of the thesis focuses on the assessment of different thermal spray coatings used for manufacture of mechanical seals in pumps and analyze the best coating material for the wear resistance application through detail quantification of material loss by block-on-ring test set-up. A machine based on Block-on-ring test set-up following ASTM G77 (Measurement of Adhesive wear resistance of thermal spray coatings) standards was built to duplicate the pump conditions. Thermally sprayed coated materials were tested in different conditions (Load, time, abrasive). WC-Co had the highest wear resistance (lower volume losses) and

  10. Wear Behavior of Selected Nuclear Grade Graphites at Room Temperature in Ambient Air Environment

    International Nuclear Information System (INIS)

    Kim, Eung-Seon; Park, Kwang-Seok; Kim, Yong-Wan

    2008-01-01

    In a very high temperature reactor (VHTR), graphite will be used not only for as a moderator and reflector but also as a major structural component due to its excellent neutronic, thermal and mechanical properties. In the VHTR, wear of graphite components is inevitable due to a neutron irradiation-induced dimensional change, thermal gradient, relative motions of graphite components and a shock load such as an earthquake. Large wear particles accumulated at the bottom of a reactor can influence the cooling of the lower part and small wear particles accumulated on the primary circuit and heat exchanger tube can make it difficult to inspect the equipment, and also decrease the heat exchange rate. In the present work, preliminary wear tests were performed at room temperature in ambient air environment to understand the basic wear characteristics of selected nuclear grade graphites for the VHTR

  11. Microstructure and wear behavior of austempered high carbon high silicon steel

    Directory of Open Access Journals (Sweden)

    Acharya Palaksha

    2018-01-01

    Full Text Available In the present investigation, the influence of austempering temperature and time on the microstructure and dry sliding wear behavior of high silicon steel was studied. The test specimens were initially austenitised at 900°C for 30 minutes, thereafter austempered at various temperatures 280°C, 360°C and 400°C, for varying duration from 30 to 120 minutes. These samples after austempering heat treatment were subsequently air cooled to room temperature, to generate typical ausferritic microstructures and then correlated with the wear property. The test outcomes demonstrate the slight increase in specific wear rate with increase in both austempering temperature and time. Specific wear rate was found to be minimum at an austempering temperature of 280°C, that exhibits lower bainite microstructure with high hardness, on the other hand specific wear rate was found to be slightly high at increased austempering temperatures at 360°C and 400°C, due to the upper bainite structure that offered lower hardness to the matrix. The sample austempered at 280°C for 30 minutes offered superior wear resistance when compared to other austempering conditions, mainly due to the presence of fine acicular bainitic ferrite along with stabilized retained austenite and also some martensite in the microstructure.

  12. Thermal Conductivity and Wear Behavior of HVOF-Sprayed Fe-Based Amorphous Coatings

    Directory of Open Access Journals (Sweden)

    Haihua Yao

    2017-10-01

    Full Text Available To protect aluminum parts in vehicle engines, metal-based thermal barrier coatings in the form of Fe59Cr12Nb5B20Si4 amorphous coatings were prepared by high velocity oxygen fuel (HVOF spraying under two different conditions. The microstructure, thermal transport behavior, and wear behavior of the coatings were characterized simultaneously. As a result, this alloy shows high process robustness during spraying. Both Fe-based coatings present dense, layered structure with porosities below 0.9%. Due to higher amorphous phase content, the coating H-1 exhibits a relatively low thermal conductivity, reaching 2.66 W/(m·K, two times lower than the reference stainless steel coating (5.85 W/(m·K, indicating a good thermal barrier property. Meanwhile, the thermal diffusivity of amorphous coatings display a limited increase with temperature up to 500 °C, which guarantees a steady and wide usage on aluminum alloy. Furthermore, the amorphous coating shows better wear resistance compared to high carbon martensitic GCr15 steel at different temperatures. The increased temperature accelerating the tribological reaction, leads to the friction coefficient and wear rate of coating increasing at 200 °C and decreasing at 400 °C.

  13. ON ASSESSMNENT OF PHYSICAL WEAR IN ELEMENTS OF TECHNICAL DEVICES

    Directory of Open Access Journals (Sweden)

    S. N. Osipov

    2015-01-01

    Full Text Available Real assessment of wear in technical devices, construction structures, minings, their elements and connections is of great importance for provision of operational security and efficiency. Natural properties of the overwhelming majority of materials follow to probabilistic (stochastic laws due to various reasons (external influence, processing technologies and others. An assessment of physical wear rate of buildings and structures and their elements is carried out in the former republics of the USSR mainly in accordance with external physical signs (deflections, cracks, layer separations, etc. but wear percentage is often calculated on the basis of replacement cost in comparison with the initial one even without taking into account inflation which did not officially exist in the USSR. In this case destruction or failure of structure or their elements are considered as 100 % wear.The paper proposes a new methodology for assessment of physical wear rate in accordance with probability ratio of nofailure operation (reliability, minimum ratio is assigned to admissible limit value in conformity with technical requirements for the technical devices, construction structures, minings in question, their elements and connections. In this context minimum permissible wear probability (reliability is taken as 100 % wear rate and its initial index is considered as 0 % wear rate. That is why wear intensity in time depends on type of value probability distribution while determining the rate of physical property. The proposed methodology is intended for probabilistic wear assessment in case of relatively simple changes in strength properties of materials (for example, within the elastic limit.

  14. Esthetic Reconstruction of Diastema with Adhesive Tooth-Colored Restorations and Hyaluronic Acid Fillers

    Directory of Open Access Journals (Sweden)

    Supawadee Naorungroj

    2017-01-01

    Full Text Available Objective. This report presents a comprehensive esthetic treatment with adhesive tooth-colored restorations in a combination with hyaluronic acid (HA fillers of diastema in an orthodontic patient with relapse. Case Report. A 36-year-old female patient consulted about 1.5–2 mm midline diastema after an orthodontic relapse of replacing missing central incisors with lateral incisors and dark-colored gingival tissue as a result of a metal post and core with porcelain fused to a metal (PFM crown at the left lateral incisor. Restorative treatments included replacing the PFM with all-ceramic material and placing a ceramic veneer on the right lateral incisor. To close the space, crown forms of both lateral incisors were altered. A direct resin composite was then used to reform right and left canines to a more ideal lateral incisor shape. An HA fillers injection was used to fill the remaining open gingival embrasure. Eighteen months after treatment, the interdental papilla remained stable and the patient was satisfied with the result. Conclusion. Esthetic reconstruction of diastema and open gingival embrasure in this case can be accomplished without orthodontic retreatment. Tooth-colored restorations and HA filler injection appear as a promising modality to address this patient’s esthetic concern.

  15. Commentary: the right time to rethink part-time careers.

    Science.gov (United States)

    Palda, Valerie A; Levinson, Wendy

    2009-01-01

    The demand for part-time academic positions is bound to increase because of the changing demographics of medicine and the needs of both women and men faculty. One of the main benefits of working part-time is the freedom to shape a career that is tailored to one's individualized life needs. Studies indicate that part-time faculty may enhance quality of care, patient satisfaction, resource utilization, and productivity. Division chiefs and department chairs who have flexible hiring policies to meet the needs of part-time faculty are likely to be more successful in recruitment and retention. The authors describe some of the benefits and drawbacks of part-time work, and they offer advice for faculty members seeking part-time careers and for leaders seeking to employ them.

  16. Investigation of friction and wear characteristics of cast iron material under various conditions

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Ji Hoon; Kim, Chang Lae; Oh, Jeong Taek; Kim, Dae Eun [Yonsei University, Seoul (Korea, Republic of); Nemati, Narguess [School of Materials and Metallurgy, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-08-15

    Cast iron is widely used in fields such as the transport and heavy industries. For parts where contact damage is expected to occur, it is necessary to understand the friction and wear characteristics of cast iron. In this study, we use cast iron plates as the specimens to investigate their friction and wear characteristics. We perform various experiments using a reciprocating type tribotester. We assess the frictional characteristics by analyzing the friction coefficient values that were obtained during the sliding tests. We observe the wear surfaces of cast iron and steel balls using a scanning electron microscope, confocal microscope, and 3D profiler. We investigate the friction and wear characteristics of cast iron by injecting sand and alumina particles having various sizes. Furthermore, we estimate the effect of temperature on the friction and wear characteristics. The results obtained are expected to aid in the understanding of the tribological characteristics of cast iron in industry.

  17. Radioisotopic measurement methods for determining the wear railway brake shoe and its rim wearing effect

    International Nuclear Information System (INIS)

    Doman, P.

    1979-01-01

    Under operating conditions the wear of brake shoe was tested by a measuring method based on the principle of radioisotopic thickness measurement. It is characteristic to the sensitivity of the method that the wear caused by the fast braking of a train (speed: 100 km/h) as well as the uneven wear distribution were determinable. Surface activating methods assuring the periodic and continuous evaluation were also developed. A test was performed with galvanic surface activation under operating conditions to determine the rim wearing effect of the brake shoe. Apart from the operational tests a new method based on activated wear measurement was also developed. (author)

  18. Natural Tooth Pontic: An Instant Esthetic Option for Periodontally Compromised Teeth—A Case Series

    Directory of Open Access Journals (Sweden)

    Rishi Raj

    2016-01-01

    Full Text Available Sudden tooth loss in the esthetic zone of the maxillary or mandibular anterior region can be due to trauma, periodontal disease, or endodontic failure. The treatment options for replacing the missing tooth can vary between removable prosthesis, tooth-supported prosthesis, and implant-supported prosthesis. Irrespective of the final treatment, the first line of management would be to provisionally restore the patient’s esthetic appearance at the earliest, while functionally stabilizing the compromised arch. Using the patient’s own natural tooth as a pontic offers the benefits of being the right size, shape, and color and provides exact repositioning in its original intraoral three-dimensional position. Additionally, using the patient’s platelet concentrate (platelet rich fibrin facilitates early wound healing and preservation of alveolar ridge shape following tooth extraction. The abutment teeth can also be preserved with minimal or no preparation, thus keeping the technique reversible, and can be completed at the chair side thereby avoiding laboratory costs. This helps the patient better tolerate the effect of tooth loss psychologically. The article describes a successful, immediate, and viable technique for rehabilitation of three different patients requiring replacement of a single periodontally compromised tooth in an esthetic region.

  19. Improvement in smile esthetics following orthodontic treatment: a retrospective study utilizing standardized smile analysis.

    Science.gov (United States)

    Maganzini, Anthony L; Schroetter, Sarah B; Freeman, Kathy

    2014-05-01

    To quantify smile esthetics following orthodontic treatment and determine whether these changes are correlated to the severity of the initial malocclusion. A standardized smile mesh analysis that evaluated nine lip-tooth characteristics was applied to two groups of successfully treated patients: group 1 (initial American Board of Orthodontics Discrepancy Index [DI] score20). T-tests were used to detect significant differences between the low-DI and high-DI groups for baseline pretreatment measurements, baseline posttreatment measurements, and changes from pre- to posttreatment. A Spearman correlation test compared the initial DI values with the changes in the nine smile measurements. Five of the smile measurements were improved in both groups following orthodontic treatment. Both groups demonstrated improved incisor exposure, an improved gingival smile line, an increase in smile width, a decreased buccal corridor space, and an improvement in smile consonance. Spearman correlation tests showed that initial DI value was not correlated to changes in any of the individual smile measurements. Smile esthetics is improved by orthodontic treatment regardless of the initial severity of the malocclusion. In other words, patients with more complex orthodontic issues and their counterparts with minor malocclusions benefitted equally from treatment in terms of their smile esthetics.

  20. Wear behavior of AA 5083/SiC nano-particle metal matrix composite: Statistical analysis

    Science.gov (United States)

    Hussain Idrisi, Amir; Ismail Mourad, Abdel-Hamid; Thekkuden, Dinu Thomas; Christy, John Victor

    2018-03-01

    This paper reports study on statistical analysis of the wear characteristics of AA5083/SiC nanocomposite. The aluminum matrix composites with different wt % (0%, 1% and 2%) of SiC nanoparticles were fabricated by using stir casting route. The developed composites were used in the manufacturing of spur gears on which the study was conducted. A specially designed test rig was used in testing the wear performance of the gears. The wear was investigated under different conditions of applied load (10N, 20N, and 30N) and operation time (30 mins, 60 mins, 90 mins, and 120mins). The analysis carried out at room temperature under constant speed of 1450 rpm. The wear parameters were optimized by using Taguchi’s method. During this statistical approach, L27 Orthogonal array was selected for the analysis of output. Furthermore, analysis of variance (ANOVA) was used to investigate the influence of applied load, operation time and SiC wt. % on wear behaviour. The wear resistance was analyzed by selecting “smaller is better” characteristics as the objective of the model. From this research, it is observed that experiment time and SiC wt % have the most significant effect on the wear performance followed by the applied load.

  1. Esthetic Assessment of the Effect of Gingival Exposure in the Smile of Patients with Unilateral and Bilateral Maxillary Incisor Agenesis.

    Science.gov (United States)

    Pinho, Teresa; Bellot-Arcís, Carlos; Montiel-Company, José María; Neves, Manuel

    2015-07-01

    The aim of this study was to determine the dental esthetic perception of the smile of patients with maxillary lateral incisor agenesis (MLIA); the perceptions were examined pre- and post-treatment. Esthetic determinations were made with regard to the gingival exposure in the patients' smile by orthodontists, general dentists, and laypersons. Three hundred eighty one people (80 orthodontists, 181 general dentists, 120 laypersons) rated the attractiveness of the smile in four cases before and after treatment, comprising two cases with unilateral MLIA and contralateral microdontia and two with bilateral MLIA. For each case, the buccal photograph was adjusted using a computer to apply standard lips to create high, medium, and low smiles. A numeric scale was used to measure the esthetic rating perceived by the judges. The resulting arithmetic means were compared using an ANOVA test, a linear trend, and a Student's t-test, applying a significance level of p esthetic perception of smiles in post-treatment cases. © 2014 by the American College of Prosthodontists.

  2. Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

    OpenAIRE

    Shibe, Vineet; Chawla, Vikas

    2016-01-01

    Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 ste...

  3. Provision of wear resistance and fatigue strength of surfaces during electroerosive processing

    Science.gov (United States)

    Fedonin, O. N.; Syanov, S. Yu; Papikyan, A. M.

    2018-03-01

    This article is a generalization of the results of theoretical studies of the effect of erosion control regimes on the operational properties of mold-forming parts of molds. The main problem is the provision of wear resistance and fatigue strength in the electroerosion processing of these types of products. The analysis showed that the fatigue strength is affected by the processing regimes and the coefficient after the erosion treatment. The index of wear resistance is determined both by the treatment modes and by the physical-mechanical properties of the billet materials. To ensure the operational performance of products, it is necessary to establish the physical picture of the processing of complex profile parts by finding the optimum eroding regime.

  4. An esthetics rehabilitation with computer-aided design/ computer-aided manufacturing technology.

    Science.gov (United States)

    Mazaro, Josá Vitor Quinelli; de Mello, Caroline Cantieri; Zavanelli, Adriana Cristina; Santiago, Joel Ferreira; Amoroso, Andressa Paschoal; Pellizzer, Eduardo Piza

    2014-07-01

    This paper describes a case of a rehabilitation involving Computer Aided Design/Computer Aided Manufacturing (CAD-CAM) system in implant supported and dental supported prostheses using zirconia as framework. The CAD-CAM technology has developed considerably over last few years, becoming a reality in dental practice. Among the widely used systems are the systems based on zirconia which demonstrate important physical and mechanical properties of high strength, adequate fracture toughness, biocompatibility and esthetics, and are indicated for unitary prosthetic restorations and posterior and anterior framework. All the modeling was performed by using CAD-CAM system and prostheses were cemented using resin cement best suited for each situation. The rehabilitation of the maxillary arch using zirconia framework demonstrated satisfactory esthetic and functional results after a 12-month control and revealed no biological and technical complications. This article shows the important of use technology CAD/CAM in the manufacture of dental prosthesis and implant-supported.

  5. Surface chemical modification for exceptional wear life of MEMS materials

    Directory of Open Access Journals (Sweden)

    R. Arvind Singh

    2011-12-01

    Full Text Available Micro-Electro-Mechanical-Systems (MEMS are built at micro/nano-scales. At these scales, the interfacial forces are extremely strong. These forces adversely affect the smooth operation and cause wear resulting in the drastic reduction in wear life (useful operating lifetime of actuator-based devices. In this paper, we present a surface chemical modification method that reduces friction and significantly extends the wear life of the two most popular MEMS structural materials namely, silicon and SU-8 polymer. The method includes surface chemical treatment using ethanolamine-sodium phosphate buffer, followed by coating of perfluoropolyether (PFPE nanolubricant on (i silicon coated with SU-8 thin films (500 nm and (ii MEMS process treated SU-8 thick films (50 μm. After the surface chemical modification, it was observed that the steady-state coefficient of friction of the materials reduced by 4 to 5 times and simultaneously their wear durability increased by more than three orders of magnitude (> 1000 times. The significant reduction in the friction coefficients is due to the lubrication effect of PFPE nanolubricant, while the exceptional increase in their wear life is attributed to the bonding between the -OH functional group of ethanolamine treated SU-8 thin/thick films and the -OH functional group of PFPE. The surface chemical modification method acts as a common route to enhance the performance of both silicon and SU-8 polymer. It is time-effective (process time ≤ 11 min, cost-effective and can be readily integrated into MEMS fabrication/assembly processes. It can also work for any kind of structural material from which the miniaturized devices are/can be made.

  6. Isolation of coagulase-negative staphylococci from extended-wear soft contact lenses in asymptomatic patients.

    Science.gov (United States)

    Faghri, Jamshid

    2008-05-01

    Coagulase-negative staphylococci and diphtheroids are normal inhabitants of the outer surface of the human eye. These microorganisms serve as part of the defense mechanism of the ocular anatomy in preventing colonization and infection by pathogenic bacteria. Nevertheless, infections associated with contaminated solutions and cases became serious problems for people who wear soft contact lenses. The aim of this study is to isolate and identify aerobic bacteria, particularly, gram-negative species associated with the use of extended-wear soft contact lenses. Extended-wear contact lenses were collected, using aseptic technique, from the eyes of individuals after 30 days of extended wear (5-7 day intermittent periods) and were examined for adhered aerobic bacteria. Coagulase-negative staphylococci were isolated from 74% of the lenses. Serratia marcescens was found at an incidence of 10% and Pseudomonas aeruginosa at an incidence of 6%. The presence of species of bacteria, including P. aeruginosa and S. marcescens, which have been associated with daily wear soft contact lenses, solutions, and cases also seem to be associated with extended-wear lenses.

  7. Chinua Achebe and the Post-colonial Esthetic: Writing, Identity, and National Formation

    Directory of Open Access Journals (Sweden)

    Simon Gikandi

    1991-01-01

    Full Text Available Chinua Achebe is recognized as one of Africa's most important and influential writers, and his novels have focused on the ways in which the European tradition of the novel and African modes of expression relate to each other in both complementary and contesting ways. Achebe's novels are informed by an important theory of writing which tries to mediate the politics of the novel as a form of commentary on the emergence and transformation of nationalism which constitutes the African writer's epistemological context. Achebe's esthetic has been overdetermined by the changing discourse on representation and national identity in colonial and post-colonial Africa. His anxious quest for a post-colonial esthetic is predicated on the belief that narrative can enable the writer to express an alternative order of things opposed to realities imprisoned by imperialism and Western domination.

  8. Friction and wear calculation methods

    CERN Document Server

    Kragelsky, I V; Kombalov, V S

    1981-01-01

    Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

  9. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  10. Investigation of Wear Behavior of Aluminum Matrix Composite Reinforced by Al2O3 and Produced by Hot Pressing Process

    Directory of Open Access Journals (Sweden)

    Halil ARIK

    2017-12-01

    Full Text Available In this study, Al powder produced by gas atomization technique has 72.06 µm average particle size and 99 % purity was mixed with as a reinforcement Al2O3 has 99.52% purity and 45 submicron particle size in a high energy ball mill for two hours. In order to obtain disk samples with 30 mm diameter and 6 mm thick mixed powders, after the characterization of particle size and morphology, were compacted in a single action press. Compaction process were carried out from mixed powders by hot pressing at 200 MPa pressure and 550 °C temperature for two hours. Then microstructural analysis, hardness and density measurements of powder metal composite parts were performed. After, the characterization of samples abrasion wear tests were performed according to ASTM-G99-05 by using TRIBOMETER T10/20 ball-on-disk abrasive wearing device. After the abrasive wear test of aluminum and composite powder metal parts produced under the identical test parameters, test results were compared and effect of Al2O3 on the wear properties of composite materials was exhibited. The test results showed that the composite parts have 62 % extra harness and better abrasion wear performance according to aluminum powder metal parts produced and tested under the identical conditions

  11. Wear Micro-Mechanisms of Composite WC-Co/Cr - NiCrFeBSiC Coatings. Part I: Dry Sliding

    Directory of Open Access Journals (Sweden)

    D. Kekes

    2014-12-01

    Full Text Available The influence of the cermet fraction in cermet/ metal composite coatings developed by High-Velocity Oxyfuel Flame (HVOF spraying on their tribological behaviour was studied. Five series of coatings, each one containing different proportion of cermet-metal components, prepared by premixing commercially available feedstocks of NiCrFeBSiC metallic and WC-Co/Cr cermet powders were deposited on AISI 304 stainless steel substrate. The microstructure of as-sprayed coatings was characterized by partial decomposition of the WC particles, lamellar morphology and micro-porosity among the solidified splats. Tribological behavior was studied under sliding friction conditions using a Si3N4 ball as counterbody and the friction coefficient and volume loss were determined as a function of the cermet fraction. Microscopic examinations of the wear tracks and relevant cross sections identified the wear mechanisms involved. Coatings containing only the metallic phase were worn out through a combination of ploughing, micro-cracking and splat exfoliation, whilst those containing only the cermet phase primarily by micro-cracking at the individual splat scale. The wear mechanisms of the composite coatings were strongly affected by their randomly stratified structure. In-depth cracks almost perpendicular to the coating/ substrate interface occurring at the wear track boundaries resulted in cermet trans-splat fracture.

  12. The esthetic metal-ceramic margin: a comparison of techniques.

    Science.gov (United States)

    Prince, J; Donovan, T

    1983-08-01

    Metal-ceramic crowns with all-porcelain labial margins may have esthetic and biologic advantages. Several techniques for making these restorations have been described in the prosthodontic literature. The authors used all the techniques and compared the results in terms of quality and degree of difficulty in construction. Clinically acceptable results can be achieved with all described techniques. The advantages and disadvantages of each method are summarized in Table I.

  13. Use of modified lip repositioning technique associated with esthetic crown lengthening for treatment of excessive gingival display: A case report of multiple etiologies

    Science.gov (United States)

    Mantovani, Matheus Bortoluzzi; Souza, Eduardo Clemente; Marson, Fabiano Carlos; Corrêa, Giovani Oliveira; Progiante, Patrícia Saram; Silva, Cléverson Oliveira

    2016-01-01

    Excessive gingival display during smile can result in compromised esthetics. This study aims to report a case of excessive gingival display with multiple etiologies treated by means of modified lip repositioning technique associated with esthetic crown lengthening. A 23-year-old female patient, with 5-mm gingival display during smile caused by altered passive eruption and hypermobility of the upper lip, underwent the modified lip repositioning technique associated with gingivectomy followed by flap elevation and ostectomy/osteoplasty. Seven months after the second procedure, the patient had her esthetic complaint solved appearing stable in the observation period. The modified lip repositioning technique is an effective procedure employed to reduce gingival display and when associated with esthetic clinical crown lengthening, can appropriately treat cases of gummy smile. PMID:27041845

  14. Part-time vs. full-time occlusion for amblyopia: evidence for part-time patching.

    Science.gov (United States)

    Matta, Noelle S; Silbert, David I

    2013-01-01

    Amblyopia is characterized by a decreased uncorrectable visual acuity in a structurally normal eye. Occlusion therapy has been used for years to improve acuity, and, traditionally, practitioners have utilized full-time patching. This article will explore more recent research looking at using part-time patching in the treatment of amblyopia.

  15. Perceptual Veridicality in Esthetic Communication: A Model, General Procedure, and Illustration.

    Science.gov (United States)

    Holbrook, Morris B.; Bertges, Stephen A.

    1981-01-01

    Developed a model and tested the following hypotheses: (1) esthetic features--tempo, rhythm, dynamics, and phrasing in piano performance--are accurately perceived by audience members and (2) such perceptual veridicality does not depend upon one's degree of education/training and is therefore shared by critics and audience members. (PD)

  16. Multi technical analysis of wear mechanisms in axial piston pumps

    Science.gov (United States)

    Schuhler, G.; Jourani, A.; Bouvier, S.; Perrochat, J.-M.

    2017-05-01

    Axial piston pumps convert a motor rotation motion into hydraulic or pneumatic power. Their compactness and efficiency of approximately 0.9 make them suitable for actuation applications especially in aeronautics. However, they suffer a limited life due to the wear of their components. In the literature, studies of axial piston pumps deal with contact between its different elements under lubrication conditions. Nevertheless, they are more focused on analytic or numerical approaches. This study consists in an experimental analysis of worn pump components to highlight and understand wear mechanisms. Piston shoes are central components in the axial piston pump since they are involved in three tribological contacts. These three contacts are thereby studied: piston shoes/swashplate, piston shoes/pistons and piston shoes/shoes hold down plate (SHDP). To perform this analysis, helicopter hydraulic pumps after different operating times have been studied. The wear damage mechanisms and wear debris are analysed using SEM observations. 3D surface roughness measurements are then used to characterize worn surfaces. The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse carbides removal. Between shoes and pistons, wear occurs in a less severe way and is mainly due to the debris generated in the first contact and conveyed by the lubricating fluid. In the third contact, the debris are also the prime cause of the abrasive wear and the generation of deep craters in the piston shoes.

  17. Wear-resistant ball bearings for space applications

    Science.gov (United States)

    Boving, H.; Hintermann, H. E.; Hanni, W.; Bondivenne, E.; Boeto, M.; Conde, E.

    1977-01-01

    Ball bearings consisting of steel parts of which the rings are coated with hard, wear resistant, chemical vapor deposited TiC are described. Experiments conducted in ultrahigh vacuum, using cages of various materials with self-lubricating properties, show that such bearings are suitable for space applications. The results of laboratory tests on the ESA Meteosat Radiometer Focalizing mechanism, which contains six coated bearings, are summarized.

  18. Esthetic evaluation of timber harvesting in the Northern Rockies - a progressive report

    Science.gov (United States)

    Dennis L. Schweitzer; James R. Ullrich; Robert E. Benson

    1976-01-01

    Panels of judges have been evaluating the esthetic dimension of harvested areas in the Northern Rockies. Studies conducted in Wyoming and Montana agree with intuition in that forest scenes are generally liked less as the evidence of man's activities increases.

  19. Esthetic perception and economic value of orthodontic appliances by lay Brazilian adults

    Directory of Open Access Journals (Sweden)

    Daniela Feu

    2012-10-01

    Full Text Available OBJECTIVE: To evaluate the esthetic perception of different appliances by Brazilian lay adults and its influence in the attributed value of orthodontic treatment, considering evaluators' socioeconomic status, age and gender. METHODS: Eight different combinations of orthodontic appliances and clear tray aligners were placed in a consenting adult with pleasing smile. Standardized frontal photographs were captured and incorporated into a research album. A sample of adults (n = 252, median = 26 years old were asked to rate each image for (1 its attractiveness on a visual analog scale and (2 the willingness to pay (WTP for a cosmetic appliance when compared to a standard metalic appliance and a clear tray aligner. Comparisons between the appliances' attractiveness were performed using the Friedman's test and Dann's post-hoc test. Correlation between appliances' attributed value, socioeconomic status, age, gender, and esthetic perception was assessed using Spearman's correlation analysis. RESULTS: Attractiveness ratings of orthodontic appliances varied significantly in the following hierarchy: Clear aligners>sapphire brackets>self-ligating/conventional stainless steel brackets>and golden metal appliances. The correlation between WTP and esthetic perception was week. However, for individuals with better socioeconomic status and aged between 17-26 years old significantly, a significantly higher WTP was found. CONCLUSION: Clear aligners and sapphire brackets with esthetic archwire were considered better esthetic options in this sample. Nevertheless, patients were not willing to pay more money for appliances they deemed more esthetic, however, they were significantly influenced by their socioeconomic level and age.OBJETIVO: avaliar a percepção de brasileiros adultos leigos para diferentes aparelhos ortodônticos e sua influência na valorização econômica do tratamento, considerando o nível socioeconômico, idade e sexo dos avaliadores. M

  20. Gingival zenith and its role in redefining esthetics: A clinical study

    Directory of Open Access Journals (Sweden)

    Babita Pawar

    2011-01-01

    Full Text Available Background: The purpose of this study was to quantify some clinical parameters useful as esthetic guidelines when gingival contour is modified and to compare the left and right sides of six maxillary anterior teeth. Materials and Methods: Maxillary casts mounted on an articulator according to the axis orbital plane were photographed from 35 young adults. The angle formed between the gingival line and maxillary midline (GLA and the distance between the gingival zenith of the lateral incisor and the gingival line were measured (LID using a flexible protractor and digital vernier caliper, respectively. The asymmetry was evaluated using a paired t test for the left vs right measurements of GLA and LID. The descriptive statistics for GLA and LID were calculated. Results: The GLA measurements of the left side (86.7΀΁4.2΀ were significantly greater than those of the right side (84.6΀΁5.4΀, and the mean absolute symmetry for GLA was 1.7΀΁4.4΀. The mean LID measurement was 0.92΁0.11. Conclusions: The gingival zenith of the canine is apical to the gingival zenith of the incisors (GLA <90΀ and the gingival zenith of the lateral incisor is below or on (17% the gingival line when head is oriented on the axis orbital plane. A directional asymmetry was shown with the right side higher than the left side. Along with the other parameters related to dental esthetics, these clinical parameters may serve as esthetic guidelines and may enable us to obtain a more predictable outcome.

  1. Determination of a Wear Initiation Cycle by using a Contact Resistance Measurement in Nuclear Fuel Fretting

    International Nuclear Information System (INIS)

    Lee, Young Ho; Kim, Hyung Kyu

    2008-01-01

    In nuclear fuel fretting, the improving of the contact condition with a modified spring shape is a useful method for increasing the wear resistance of the nuclear fuel rod. This is because the fretting wear resistance between the fuel rod and grid spring is mainly affected by the grid spring shape rather than the environment, the contact modes, etc. In addition, the wear resistance is affected by the wear debris behavior between contact surfaces. So, it is expected that the wear initiation of each spring shape should be determined in order to evaluate a wear resistance. However, it is almost impossible to measure the wear behavior in contact surfaces on a real time basis because the contact surfaces are always hidden. Besides, the results of the worn surface observation after the fretting wear tests are restricted to archive the information on the wear debris behavior and the formation mechanism of the wear scar. In order to evaluate the wear behavior during the fretting wear tests, it is proposed that the contact resistance measurement is a useful method for examining the wear initiation cycle and modes. Generally, fretting wear damages are rapidly progressed by a localized plastic deformation between the contact surfaces, crack initiation and fracture of the deformed surface with a strain hardening difference between a surface and a subsurface and finally a detachment of wear debris. After this, wear debris is easily oxidized by frictional heat, test environment, etc. At this time, a small amount of electric current applied between the contact surfaces will be influenced by the wear debris, which could be an obstacle to an electric current flow. So, it is possible to archive the information on the wear behavior by measuring the contact resistance. In order to determine the wear initiation cycle during the fretting wear tests, in this study, fretting wear tests have been performed by applying a constant electric current in room temperature air

  2. Corrosion-wear of β-Ti alloy TMZF (Ti-12Mo-6Zr-2Fe) in simulated body fluid.

    Science.gov (United States)

    Yang, Xueyuan; Hutchinson, Christopher R

    2016-09-15

    Titanium alloys are popular metallic implant materials for use in total hip replacements. Although, α+β titanium alloys such as Ti-6Al-4V have been the most commonly used alloys, the high Young's modulus (∼110GPa) leads to an undesirable stress shielding effect. An alternative is to use β titanium alloys that exhibit a significantly lower Young's modulus (∼70GPa). Femoral stems made of a β titanium alloy known as TMZF (Ti-12Mo-6Zr-2Fe (wt.%)) have been used as part of modular hip replacements since the early 2000's but these were recalled in 2011 by the US Food & Drug Administration (FDA) due to unacceptable levels of 'wear debris'. The wear was caused by small relative movement of the stem and neck at the junction where they fit together in the modular hip replacement design. In this study, the corrosion and wear properties of the TMZF alloy were investigated in simulated body fluid to identify the reason for the wear debris generation. Ti64 was used as a control for comparison. It is shown that the interaction between the surfaces of Ti64 and TMZF with simulated body fluid is very similar, both from the point of view of the products formed and the kinetics of the reaction. The dry wear behaviour of TMZF is also close to that of Ti64 and consistent with expectations based on Archard's law for abrasive wear. However, wear of Ti64 and TMZF in simulated body fluid show contrasting behaviours. A type of time-dependent wear test is used to examine the synergy between corrosion and wear of TMZF and Ti64. It is shown that the wear of TMZF accelerated rapidly in SBF whereas that of Ti64 is reduced. The critical role of the strain hardening capacity of the two materials and its role in helping the surface resist abrasion by hydroxyapatite particles formed as a result of the reaction with the SBF is discussed and recommendations are made for modifications that could be made to the TMZF alloy to improve the corrosion-wear response. TMZF is a low modulus β-Ti alloy

  3. Alternate paddle configuration for improved wear resistance in the saltstone mixer

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2013-09-23

    The Saltstone Production Facility has a 10-inch Readco-Kurimoto continuous mixer that mixes the premix dry feeds and low-level waste salt solution to make fresh (uncured) saltstone. Inspection of the mixer in January 2013 showed significant wear on the third, fourth and fifth paddle pairs after the conveying augers. A 2-inch Readco-Kurimoto continuous mixer was used to test alternate paddle configurations for use in the 10-inch mixer to decrease the wear rate on the paddles. Two wear tests were conducted to investigate a method of reducing wear on the mixer paddles. The first test (wear test 2a) had a paddle configuration similar to the currently installed 10-inch mixer in the SPF. This test established baseline wear. The second test (wear test 2b) had a reconfigured paddle arrangement that replaced the flat paddles with helical paddles for paddle pairs 2 - 6 and aligned paddle pair 1 with the augers. The intent of the reconfiguration was to more effectively convey the partially wetted dry feeds through the transition region and into the liquid feed where paddle wear is reduced due to dry feeds and salt solution being mixed at the intended water to premix ratio. The design of the helical paddles provides conveyance through the transition region to the liquid feed inlet. The alignment with the auger is aimed to provide a smoother transition (minimizing the discontinuity between the auger and paddle pair 1) into the downstream paddles. A soft metal with low wear resistance (6000 series aluminum) was used for the wear testing paddles to determine wear patterns while minimizing run time and maximizing wear rate. For the two paddle configurations tested using the scaled 2-inch Readco-Kurimoto continuous mixer, with the first six paddles after the augers replaced by the wear paddles and the remaining paddles were stainless steel. Since the 10-inch SPF mixer is designed with the liquid inlet centered over paddle pairs 5 and 6, the scaled 2-inch mixer was configured the

  4. Wear mechanisms in ceramic hip implants.

    Science.gov (United States)

    Slonaker, Matthew; Goswami, Tarun

    2004-01-01

    The wear in hip implants is one of the main causes for premature hip replacements. The wear affects the potential life of the prosthesis and subsequent removals of in vivo implants. Therefore, the objective of this article is to review various joints that show lower wear rates and consequently higher life. Ceramics are used in hip implants and have been found to produce lower wear rates. This article discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations.

  5. Wear of control rod cluster assemblies and of instrumentation thimbles: first results obtained with the vibrateau wear simulator

    International Nuclear Information System (INIS)

    Zbinden, M.; Hersant, D.

    1993-07-01

    Several REP components are affected by a particular sort of damage called impact/sliding wear. This kind of wear, originating from flow induced vibrations, affects loosely supported tubular structures. The main involved components are: - the RCCAs claddings and the guides tubes, - the instrumentation thimbles, - the fuel rods claddings, - the SG tubes. The R and D Division is concerned with studies aiming to understand and to master the phenomena leading to this wear. The MTC Branch is charged of the study of the wear itself. Tests are carried out on wear rigs to understand and to model wear mechanisms. The following work is related to the two first wear tests campaigns on the VIBRATEAU wear simulator: - a reproducibility test series in order to assess the spreading of the experimental results, - a comparative test series on surface treatments used to improve the components war resistance. (authors). 7 figs., 2 tabs., 4 refs

  6. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mike L. Fulcher; Kenneth L. Knittel

    2004-06-08

    The work performed on this program was to develop wear resistant, tough FM composite materials with efforts focused on WC-Co based FM systems. The materials were developed for use in mining industry wear applications. Components of interest were drill bit inserts for drilling blast holes. Other component applications investigated included wear plates for a variety of equipment such as pit shovels, wear surfaces for conveyors, milling media for ball milling operations, hydrocyclone cones, grader blades and dozer teeth. Cross-cutting technologies investigated included hot metal extrusion dies, drill bits for circuit board fabrication, cutting tools for cast iron and aluminum machining. An important part of the work was identification of the standard materials used in drilling applications. A materials trade study to determine those metals and ceramics used for mining applications provided guidance for the most important materials to be investigated. WC-Co and diamond combinations were shown to have the most desirable properties. Other considerations such as fabrication technique and the ability to consolidate shifted the focus away from diamond materials and toward WC-Co. Cooperating partners such as Kennametal and Kyocera assisted with supplies, evaluations of material systems, fabricated parts and suggestions for cross-cutting technology applications for FM architectures. Kennametal provided the raw materials (WC-Co and Al-TiCN powders) for the extent of the material evaluations. Kyocera shared their research into various FM systems and provided laboratory testing of fabricated materials. Field testing provided by partners Superior Rock Bit and Brady Mining and Construction provided insight into the performance of the fabricated materials under actual operational conditions. Additional field testing of cross-cutting technology, the extrusion of hot metals, at Extruded Metals showed the potential for additional market development.

  7. Esthetic enhancement of a traumatized anterior tooth with a combination of forced eruption and tooth alignment: a case report

    Science.gov (United States)

    Kang, So-Hee; Jin, Myoung-Uk; Kim, Sung-Kyo

    2016-01-01

    Exposing sound structure of a subgingivally fractured tooth using orthodontic extrusion is considered to be a conservative way to re-establish biologic width without sacrificing esthetics or jeopardizing periodontal support of neighboring teeth. When a misaligned tooth is traumatically involved, a more comprehensive approach combining tooth extrusion and re-alignment may be necessary for a successful restorative outcome. This case report describes a successful esthetic management of a patient with complicated crown-root fracture on the maxillary right central incisor and pre-existing malocclusion in the maxillary anterior region. Forced eruption along with re-alignment of teeth by orthodontic movement seems to allow re-positioning of the fracture line to a favorable position and correction of crowding, providing a better esthetic result. PMID:27508163

  8. On-line monitoring of wear and/or corrosion processes by thin layer activation technique

    International Nuclear Information System (INIS)

    Alexandreanu, B.; Popa-Simil, L.; Voiculescu, D.; Racolta, P.M.

    1995-01-01

    The Thin Layer Activation (TLA) principle consists in creating a radioactive layer by ion beam irradiation of a machine part subjected to wear. The method is based on the determination of the increasing radioactivity in the lubricant due to suspended wear particles and has a sensitivity threshold of about 40 μ g / cm 2 . The most used radioactive markers are 56 Co, 57 Co, 65 Zn, 51 Cr, 48 V, 124 Sb. In this paper, we have chosen to present an on-line wear level determination experiment performed for a thermal engine. The study of possible influence of a SR3 added lubricant upon the wear level of a Dacia 1410 car engine is presented, illustrating the on-line TLA based monitoring of wear for industrial uses. The examples presented outline the advantages of this method over the conventional one, like the fast response and the high sensitivity, while no dismantling of the engine is implied. (author)

  9. Autotransplantation of a Strange Positioned Impacted Central Incisor in a surgically Prepared Socket: A Miracle Esthetic Concept.

    Science.gov (United States)

    Jaiswara, Chandresh; Srivastava, Vinay K; Dhiman, Neeraj

    2016-01-01

    Esthetics is a prime concern for a young lady. Any anomaly in the anterior tooth may create anxiety and depression. This anxiety and depression may hamper her married life and overall personality. This case report reveals an unerupted right central incisor situated in a strange position, creating space in the maxillary anterior region and giving an unesthetic appearance. Autotransplantation is a method of choice for a strangely positioned impacted central incisor in a new appropriate site. This method offers a new treatment option for some clinical situations if orthodontic approach is not possible. It permits tooth movement to a distant or the opposite side of the same dental arch as well as to the opposite jaw. This procedure also offers potential benefits of reestablishment of normal alveolar process development, esthetics, functions, and arch integrity. This procedure has the potential to become a viable alternative treatment plan for young patients of low socioeconomic status, allowing the reestablish-ment and restoration of a missing tooth and their functions. This article discusses methods of auto-reimplantation of a tooth in a fresh surgically prepared socket, its biological principle, and establishment of functions, esthetics, and phonetics. Jaiswara C, Srivastava VK, Dhiman N. Autotransplantation of a Strange Positioned Impacted Central Incisor in a surgically Prepared Socket: A Miracle Esthetic Concept. Int J Clin Pediatr Dent 2016;9(3):269-272.

  10. Numerical modelling of tool wear in turning with cemented carbide cutting tools

    Science.gov (United States)

    Franco, P.; Estrems, M.; Faura, F.

    2007-04-01

    A numerical model is proposed for analysing the flank and crater wear resulting from the loss of material on cutting tool surface in turning processes due to wear mechanisms of adhesion, abrasion and fracture. By means of this model, the material loss along cutting tool surface can be analysed, and the worn surface shape during the workpiece machining can be determined. The proposed model analyses the gradual degradation of cutting tool during turning operation, and tool wear can be estimated as a function of cutting time. Wear-land width (VB) and crater depth (KT) can be obtained for description of material loss on cutting tool surface, and the effects of the distinct wear mechanisms on surface shape can be studied. The parameters required for the tool wear model are obtained from bibliography and experimental observation for AISI 4340 steel turning with WC-Co cutting tools.

  11. Numerical modelling of tool wear in turning with cemented carbide cutting tools

    International Nuclear Information System (INIS)

    Franco, P.; Estrems, M.; Faura, F.

    2007-01-01

    A numerical model is proposed for analysing the flank and crater wear resulting from the loss of material on cutting tool surface in turning processes due to wear mechanisms of adhesion, abrasion and fracture. By means of this model, the material loss along cutting tool surface can be analysed, and the worn surface shape during the workpiece machining can be determined. The proposed model analyses the gradual degradation of cutting tool during turning operation, and tool wear can be estimated as a function of cutting time. Wear-land width (VB) and crater depth (KT) can be obtained for description of material loss on cutting tool surface, and the effects of the distinct wear mechanisms on surface shape can be studied. The parameters required for the tool wear model are obtained from bibliography and experimental observation for AISI 4340 steel turning with WC-Co cutting tools

  12. Optimization of turning process through the analytic flank wear modelling

    Science.gov (United States)

    Del Prete, A.; Franchi, R.; De Lorenzis, D.

    2018-05-01

    In the present work, the approach used for the optimization of the process capabilities for Oil&Gas components machining will be described. These components are machined by turning of stainless steel castings workpieces. For this purpose, a proper Design Of Experiments (DOE) plan has been designed and executed: as output of the experimentation, data about tool wear have been collected. The DOE has been designed starting from the cutting speed and feed values recommended by the tools manufacturer; the depth of cut parameter has been maintained as a constant. Wear data has been obtained by means the observation of the tool flank wear under an optical microscope: the data acquisition has been carried out at regular intervals of working times. Through a statistical data and regression analysis, analytical models of the flank wear and the tool life have been obtained. The optimization approach used is a multi-objective optimization, which minimizes the production time and the number of cutting tools used, under the constraint on a defined flank wear level. The technique used to solve the optimization problem is a Multi Objective Particle Swarm Optimization (MOPS). The optimization results, validated by the execution of a further experimental campaign, highlighted the reliability of the work and confirmed the usability of the optimized process parameters and the potential benefit for the company.

  13. A new production technique for wear resistant ring-hammers

    Directory of Open Access Journals (Sweden)

    Li Shifeng

    2011-11-01

    Full Text Available Based on a great number of laboratory experiments, a new technique has been developed for producing wear resistant ring-hammers. In this technology, lost foam casting with iron sand was combined to make mold; a special alloy was used to inoculate the molten steel, and proper heat treatment was used to further improve mechanical properties of wear resistant ring-hammers. The influence of this new production technology on the microstructure and mechanical properties of wear resistant ring-hammers was studied. Results show that iron sand molding, having the inherent characteristic of sand molding, changes the type of metallic compounds, refines crystal grains and increases the fineness of microstructure. Practical experience verified that the properties of the ring-hammers produced with this new technique are as follows: tensile strength (Rm 720 MPa, impact toughness (ak > 210 J•cm-2 and hardness > 200 HB. After water quenching from 1,080℃ (holding for 4 h and tempering at 320℃ for 3 h, the best wear resistance is obtained, and the wear resistance is 1.6 times higher than that of common high manganese ring-hammers.

  14. Color changes of esthetic orthodontic ligatures evaluated by orthodontists and patients: a clinical study

    Directory of Open Access Journals (Sweden)

    Edilene Kawabata

    Full Text Available ABSTRACT Objective: To evaluate in vivo changes in the color of esthetic elastomeric ligatures from different manufacturers. Methods: Four widely used commercial brands of elastomeric ligatures were selected and used in 20 adult patients in a split-mouth design. The ligatures were evaluated by orthodontists and patients in a double-blind manner on the day the ligatures were placed (T0 and 30 days after intraoral exposure (T1 by means of a system of staining scores. Groups were compared by Friedman test with p 0.05. Results showed that all brands underwent significant staining when exposed to the intraoral environment. Modular-crystal MorelliTM (Sorocaba, SP, Brazil showed the highest degree of staining with the median reaching the maximum value (3; while the other brands (3M UnitekTM, American OrthodonticsTM and GAC DentsplyTM showed the median equal to 1 (p < 0.001. A large individual variability in the degree of staining was also found for all brands. Conclusions: All four brands of esthetic ligatures showed significant staining, which appeared to be more pronounced for the MorelliTM brand. Changes in color of the elastomeric ligatures were perceived similarly by patients and orthodontists. The industry needs to improve the color stability of esthetic ligatures.

  15. Effect of tooth profile modification on wear in internal gears

    Science.gov (United States)

    Tunalioglu, M. S.; Tuc, B.

    2018-05-01

    Internal gears are often used in the automotive industry when two gears are required to rotate in the same direction. Tooth shapes, slippage speeds at the beginning and end of meshing are different according to the external gears. Manufacturing of internal gears is more difficult than external gears. Thus, it is necessary to determine the working conditions and wear behavior of internal gears carefully. The profile modification method in terms of strength and surface tension of the gear mechanism are performed in order to increase the load-carrying capability. In this study, profile modification method was performed in the internal gears to reduce the wear on the teeth. For this purpose, the wear of the internal gears was theoretically investigated by adapting the Archard wear equation to the internal gears. Closed circuit power circulation system was designed and manufactured to experimentally investigate the wear in internal gears. With this system, wear tests of gears made of St 50 material without profile modification and different profile modifications were made and the results were compared. Experimental study was performed in the same loading and cycle time conditions to validate the theoretical results and it was seen that the results are compatible. According to the experimental results, it is seen that in the internal gears, when profile modification done the wear is decreased in the teeth tip region.

  16. Optimizing anterior esthetics of a single-tooth implant through socket augmentation and immediate provisionalization: A case report with 7-year follow-up

    Directory of Open Access Journals (Sweden)

    Po-Sung Fu

    2012-10-01

    Full Text Available Tooth extraction inevitably accompanies alveolar ridge resorption with loss of pre-existing tissue morphology. Replacing missing teeth with dental implants has become popular, but restoring anterior teeth with implant-supported restorations is a technique-sensitive task and poses challenges for dentists. With the progress of implant dentistry, the demand for optimal esthetics has become linked with the desire for faster, easier techniques that shorten treatment time and also satisfy patients. Immediate provisionalization of a single-tooth implant provides significant benefits compared with traditional delayed protocols, such as aiding the contouring of peri-implant soft tissue and enhancing patient comfort and satisfaction. This article describes a meticulous approach to a hopeless maxillary central incisor with root fracture. The defect in the extraction socket was reconstructed using autogenous bone harvested from the chin. Four months later, an implant was installed and immediately restored. After another healing period of 6 months, the peri-implant soft tissue had been shaped and matured according to the contours of the provisional restoration. The emergence profile was used to duplicate the definitive restoration. Peri-implant esthetics was achieved through socket augmentation and immediate provisionalization of the implant. This treatment modality attained predictable and maintainable outcomes, both functionally and esthetically.

  17. The Importance of Perceptual Experience in the Esthetic Appreciation of the Body

    Science.gov (United States)

    Mele, Sonia; Cazzato, Valentina; Urgesi, Cosimo

    2013-01-01

    Several studies suggest that sociocultural models conveying extreme thinness as the widespread ideal of beauty exert an important influence on the perceptual and emotional representation of body image. The psychological mechanisms underlying such environmental influences, however, are unclear. Here, we utilized a perceptual adaptation paradigm to investigate how perceptual experience modulates body esthetic appreciation. We found that the liking judgments of round bodies increased or decreased after brief exposure to round or thin bodies, respectively. No change occurred in the liking judgments of thin bodies. The results suggest that perceptual experience may shape our esthetic appreciation to favor more familiar round body figures. Importantly, individuals with more deficits in interoceptive awareness were less prone to increase their liking ratings of round bodies after exposure, suggesting a specific risk factor for the susceptibility to the influence of the extreme thin vs. round body ideals of beauty portrayed by the media. PMID:24324689

  18. The importance of perceptual experience in the esthetic appreciation of the body.

    Science.gov (United States)

    Mele, Sonia; Cazzato, Valentina; Urgesi, Cosimo

    2013-01-01

    Several studies suggest that sociocultural models conveying extreme thinness as the widespread ideal of beauty exert an important influence on the perceptual and emotional representation of body image. The psychological mechanisms underlying such environmental influences, however, are unclear. Here, we utilized a perceptual adaptation paradigm to investigate how perceptual experience modulates body esthetic appreciation. We found that the liking judgments of round bodies increased or decreased after brief exposure to round or thin bodies, respectively. No change occurred in the liking judgments of thin bodies. The results suggest that perceptual experience may shape our esthetic appreciation to favor more familiar round body figures. Importantly, individuals with more deficits in interoceptive awareness were less prone to increase their liking ratings of round bodies after exposure, suggesting a specific risk factor for the susceptibility to the influence of the extreme thin vs. round body ideals of beauty portrayed by the media.

  19. Changes in quality of life and impact on patients′ perception of esthetics after orthognathic surgery

    Science.gov (United States)

    Kavin, Thangavelu; Jagadesan, Anbuselvan Gobichetty Palayam; Venkataraman, Siva Subramaniam

    2012-01-01

    Objectives: The aim of our study is to determine the changes in quality of life and patient′s perception of esthetic improvement after anterior maxillary osteotomy. Materials and Methods: Our prospective study consisted of 14 patients who had been diagnosed of skeletal orthodontic deformity and underwent anterior maxillary osteotomy, along with orthodontic correction. The quality of life was evaluated using questionnaires based on Oral Health Impact Profile-14 questionnaire (OHIP-14) and a 22-item orthognathic quality of life questionnaire. They were evaluated at baseline pre-surgical, 8 weeks postoperatively, and 24 weeks postoperatively. Results: Our results showed mild improvement in generic health related quality of life immediately following surgery, while condition-specific quality of life and patient′s perception of esthetic improvement were noted only at 24 weeks following anterior maxillary osteotomy. Conclusion: We conclude that anterior maxillary osteotomy had a positive impact on the quality of life. The improvement in patient's perception of esthetics is seen only 2 months after surgery, while improvements in oral health and function were seen within 2 months following surgery. The acceptance and satisfaction of patient toward surgery was more positive 2 months after surgery. PMID:23066273

  20. Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings

    Directory of Open Access Journals (Sweden)

    Vineet Shibe

    2016-01-01

    Full Text Available Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

  1. Wear-resistance of Aluminum Matrix Microcomposite Materials

    Directory of Open Access Journals (Sweden)

    M. Kandeva

    2011-03-01

    Full Text Available A procedure is developed for the study of wear of aluminum alloys AlSi7 obtained by casting, reinforced by TiC microparticles, before and after heat treatment. Tribological study is realized under conditions of friction on counterbody with fixed abrasive. Experimental results were obtained for mass wear, wear rate, wear intensity and wear-resistance of the alloys with different wt% of microparticles.

  2. State of art report for high temperature wear test of SMART MCP and CEDM bearing material

    International Nuclear Information System (INIS)

    Cho, Yong Hu; Lee, Jae Seon; Park, Jin Seok; Kim, Ji Ho; Kim, Jong In

    2000-03-01

    Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

  3. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  4. Corrosive wear. Evaluation of wear and corrosive resistant materials; Noetningskorrosion. Utvaerdering av noetnings- och korrosionsbestaendiga material

    Energy Technology Data Exchange (ETDEWEB)

    Persson, H.; Hjertsen, D.; Waara, P.; Prakash, B.; Hardell, J.

    2007-12-15

    With a new purchase of a waste conveyer screw at hand, for the 'A-warehouse' at the combined power and heating plant at E.ON Norrkoeping, the request for improved construction materials was raised. The previous screw required maintenance with very short intervals due to the difficult operation conditions. With the new screw the expectation is to manage 6 months of operation without interruption. The environment for the screw has two main components that sets the demand on the materials, on one hand the corrosive products that comes along and which forms at digestion of the waste and on the other hand the abrasive content in the waste. The term of the mechanism is wear-corrosion and can give considerably higher material loss than the two mechanisms wear and corrosion separately. Combination of a strong corrosive environment together with extensive wear is something that we today have limited knowledge about. The overall objective of the project has been to establish better wear and corrosive resistant construction materials for a waste conveyer screw that will lead to reduced operational disturbance costs. The evaluation has been performed in both controlled laboratory environments and in field tests, which has given us a better understanding of what materials are more suitable in this tough environment and has given us a tool for future predictions of the wear rate of the different material. The new conveyer screw, installed in February 2007 and with which the field test have been performed, has considerably reduced the wear of the construction and the target of 6 month maintenance-free operation is met with this screw for all the evaluated materials. The wear along the screw varies very much and with a clear trend for all the materials to increase towards the feeding direction of the screw. As an example, the wear plate SS2377 (stainless duplex steel) has a useful life at the most affected areas that is calculated to be 1077 days of operation with the

  5. Partial-coverage posterior ceramic restorations. Part 1: a return to diligence.

    Science.gov (United States)

    Liebenberg, W H

    2001-01-01

    The application of multisurfaced tooth-colored restorations in the posterior dentition is an exercise in risk tolerance when dentin occupies the bulk of the tooth substrate. Not only is interfacial integrity capricious, but also a recent in vivo study has confirmed that dentin bond strengths deteriorate with time. Although the literature is replete with esthetic guidelines for posterior restitution, most practicing clinicians appreciate the prime tenet that clinical success involves more than esthetic realism in the posterior dentition. Success with indirect ceramic restorations is dependent on interfacial integrity, which, although multitudinous, is contingently related to operative competence. Innovative clinical techniques are described in this two-part article, along with a discussion of the probationary status of current adhesive options and the need for excellence in all phases of this demanding restorative sequence. Restorative success in the posterior dentition is profoundly influenced by the variability of operative competence and diligence. This article discusses the precincts of posterior indirect ceramic restorations and submits a number of innovative solutions to the clinical challenge.

  6. Edge loading has a paradoxical effect on wear in metal-on-polyethylene total hip arthroplasties.

    Science.gov (United States)

    Harris, William H

    2012-11-01

    Edge wear is an adverse factor that can negatively impact certain THAs. In some metal-on-metal THAs, it can lead to adverse tissue reactions including aseptic lymphocytic vasculitis-associated lesions and even to pseudotumor formation. In some ceramic-on-ceramic THAs, it can lead to squeaking and/or stripe wear. Edge wear in metal-on-metal and ceramic-on-ceramic THAs can also be associated with accelerated wear across the articulation of these joints. I asked: Does edge wear occur in metal-on-polyethylene (MOP) articulations? And if so, does it increase joint wear? I examined the evidence in the literature for edge wear occurring in MOP THA and then assessed the evidence in the literature for data supporting the concept that edge wear in MOP hips could accelerate wear across the articulation over time. Extensive data in the literature confirm edge wear is common in MOP THA. Surprisingly, the evidence does not support that it accelerates wear across the articulation. In fact, substantial data support the concept that it does not. These observations suggest, in terms of edge wear accelerating overall wear, MOP articulation may have a privileged position compared to hard-on-hard THA articulations.

  7. Wear mechanisms of toughened zirconias

    International Nuclear Information System (INIS)

    Becker, P.C.; Libsch, T.A.; Rhee, S.K.

    1985-01-01

    The dry friction and wear behavior of toughened zirconias against hardened steel was studied using the falex ring and block technique. Three experimental ZrO 2 -Y 2 O 3 ceramics and two commerical ZrO 2 -MgO ceramics were investigated. Each ceramic was tested at 500 and 2000 rpm at normal loads in the range 2.3 to 40.8 kg. Significant trends in the friction and wear data were found correlating composition, test speeds, and loads. Microstructural examination of the ring, ceramic block, and wear debris has shown that the wear process is very complex and incorporates a number of mechanisms

  8. Radiation tagging measures wear at speed

    International Nuclear Information System (INIS)

    Barrett, Jon.

    1994-01-01

    A new non-invasive technique for performing accelerated wear and corrosion analysis is particularly relevant to power transmission systems. Wear tests that would normally take days or weeks to complete can now be performed in hours. A tiny patch of the wearing component is made mildly radioactive and the drop in activity as material is worn away is monitored. Known as Thin Layer Activation (TLA), the technology was originally developed and pioneered in-house by the Atomic Energy Authority. Since then, the dominant partner has been the automotive sector where TLA has been used extensively for engine wear and lubrication performance analysis. However, TLA could be used in any wear or corrosion environment. Applications include wear analysis of machine tool cutting surfaces, pump impellers and brake linings to the corrosion monitoring of process plant and pipelines. (author)

  9. Wear performance of laser processed tantalum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Dittrick, Stanley; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

    2011-12-01

    This first generation investigation evaluates the in vitro tribological performance of laser-processed Ta coatings on Ti for load-bearing implant applications. Linear reciprocating wear tests in simulated body fluid showed one order of magnitude less wear rate, of the order of 10{sup -4} mm{sup 3}(N.m){sup -1}, for Ta coatings compared to Ti. Our results demonstrate that Ta coatings can potentially minimize the early-stage bone-implant interface micro-motion induced wear debris generation due to their excellent bioactivity comparable to that of hydroxyapatite (HA), high wear resistance and toughness compared to popular HA coatings. Highlights: {yields} In vitro wear performance of laser processed Ta coatings on Ti was evaluated. {yields} Wear tests in SBF showed one order of magnitude less wear for Ta coatings than Ti. {yields} Ta coatings can minimize early-stage micro-motion induced wear debris generation.

  10. VULNERABILITY OF PART TIME EMPLOYEES

    Directory of Open Access Journals (Sweden)

    Raluca Dimitriu

    2015-11-01

    Full Text Available The employee who concluded a part-time contract is the employee whose normal working hours, calculated weekly or as monthly average, is lower than the number of normal working hours of a comparable full-time employee. Part-time workers generally have the same legal status as full time workers. In fact, the vulnerability of this category of workers is not necessarily legal but rather economic: income - in proportion to the work performed, may be insufficient to cover the needs of living. However, such vulnerability may also have a certain cultural component: in some societies, professional identity is determined by the length of working hours. Also, part time work may hide many types of indirect discrimination.As a result, the part-time contract requires more than a protective legislation: it requires a strategy. This paper proposes a number of milestones of such a strategy, as well as some concrete de lege ferenda proposals.

  11. Fluoridation and tooth wear in Irish adults.

    LENUS (Irish Health Repository)

    Burke, F M

    2010-10-01

    The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

  12. Backside wear in modern total knee designs.

    Science.gov (United States)

    Jayabalan, Prakash; Furman, Bridgette D; Cottrell, Jocelyn M; Wright, Timothy M

    2007-02-01

    Although modularity affords various options to the orthopedic surgeon, these benefits come at a price. The unintended bearing surface between the back surface of the tibial insert and the metallic tray results in micromotion leading to polyethylene wear debris. The objective of this study was to examine the backside wear of tibial inserts from three modern total knee designs with very different locking mechanisms: Insall-Burstein II (IB II), Optetrak, and Advance. A random sample of 71 inserts were obtained from our institution's retrieval collection and examined to assess the extent of wear, depth of wear, and wear damage modes. Patient records were also obtained to determine patient age, body mass index, length of implantation, and reason for revision. Modes of wear damage (abrasion, burnishing, scratching, delamination, third body debris, surface deformation, and pitting) were then scored in each zone from 0 to 3 (0 = 0%, 1 = 0-10%, 2 = 10-50%, and 3 = >50%). The depth of wear was subjectively identified as removal of manufacturing identification markings stamped onto the inferior surface of the polyethylene. Both Advance and IB II polyethylene inserts showed significantly higher scores for backside wear than the Optetrak inserts. All IB II and Advance implants showed evidence of backside wear, whereas 17% (5 out of 30) of the retrieved Optetrak implants had no observable wear. There were no significant differences when comparing the depth of wear score between designs. The locking mechanism greatly affects the propensity for wear and should be considered when choosing a knee implant system.

  13. Wear mechanisms and friction parameters for sliding wear of micron-scale polysilicon sidewalls

    NARCIS (Netherlands)

    Alsem, D. H.; van der Hulst, R.; Stach, E. A.; Dugger, M. T.; De Hosson, J. Th. M.; Ritchie, R. O.

    As tribological properties are critical factors in the reliability of silicon-based microelectromechanical systems, it is important to understand what governs wear and friction. Average dynamic friction, wear volumes and morphology have been studied for polysilicon devices fabricated using the

  14. WEAR OF THE FRICTION SURFACES PARTS IN THE PRESENSE OF SOLID PARTICLES CONTACTING ZONE

    Directory of Open Access Journals (Sweden)

    B. M. Musaibov

    2015-01-01

    Full Text Available The problems of intensity of wear of details of the cars working in the oil polluted by abrasive particles, depending on mechanical properties of material of details and abrasive particles, their sizes, a form and concentration, loading, temperature of a surface of friction, speed of sliding, quality of lubricant are considered. 

  15. Study on the engine oil's wear based on the flash point

    Science.gov (United States)

    Niculescu, R.; Iorga-Simăn, V.; Trică, A.; Clenci, A.

    2016-08-01

    Increasing energy performance of internal combustion engines is largely influenced by frictional forces that arise between moving parts. Thus, in this respect, the nature and quality of the engine oil used is an important factor. Equally important is the effect of various engine injection strategies upon the oil quality. In other words, it's of utmost importance to maintain the quality of engine oil during engine's operation. Oil dilution is one of the most common causes that lead to its wear, creating lubrication problems. Moreover, at low temperatures operating conditions, the oil dilution with diesel fuel produces wax. When starting the engine, this may lead to lubrication deficiencies and even oil starvation with negative consequences on the engine mechanism parts wear (piston, rings and cylinders) but also crankcase bearings wear.Engine oil dilution with diesel fuel have several causes: wear of rings and/or injectors, late post-injection strategy for the sake of particulate filter regeneration, etc.This paper presents a study on the degree of deterioration of engine oils as a result of dilution with diesel fuel. The analysed oils used for this study were taken from various models of engines equipped with diesel particulate filter. The assessment is based on the determination of oil flash point and dilution degree using the apparatus Eraflash produced by Eralytics, Austria. Eraflash measurement is directly under the latest and safest standards ASTM D6450 & D7094), which are in excellent correlation with ASTM D93 Pensky - Martens ASTM D56 TAG methods; it uses the Continuous Closed Cup method for finding the Flash Point (CCCFP).

  16. [Application of digital design of orthodontic-prosthodontic multidisciplinary treatment plan in esthetic rehabilitation of anterior teeth].

    Science.gov (United States)

    Liu, Y S; Li, Z; Zhao, Y J; Ye, H Q; Zhou, Y Q; Hu, W J; Liu, Y S; Xun, C L; Zhou, Y S

    2018-02-18

    To develop a digital workflow of orthodontic-prosthodontic multidisciplinary treatment plan which can be applied in complicated anterior teeth esthetic rehabilitation, in order to enhance the efficiency of communication between dentists and patients, and improve the predictability of treatment outcome. Twenty patients with the potential needs of orthodontic-prosthodontic multidisciplinary treatment to solve their complicated esthetic problems in anterior teeth were recruited in this study. Digital models of patients' both dental arches and soft tissues were captured using intra oral scanner. Direct prosthodontic (DP) treatment plan and orthodontic-prosthodontic (OP) treatment plan were carried out for each patient. For DP treatment plans, digital wax-up models were directly designed on original digital models using prosthodontic design system. For OP treatment plans, virtual-setups were performed using orthodontic analyze system according to orthodontic and esthetic criteria and imported to prosthodontic design system to finalize the digital wax-up models. These two treatment plans were shown to the patients and demonstrated elaborately. Each patient rated two treatment plans using visual analogue scales and the medians of scores of two treatment plans were analyzed using signed Wilcoxon test. Having taken into consideration various related factors, including time, costs of treatment, each patient chose a specific treatment plan. For the patients chose DP treatment plans, digital wax-up models were exported and printed into resin diagnostic models which would be utilized in the prosthodontic treatment process. For the patients chose OP treatment plans, virtual-setups were used to fabricate aligners or indirect bonding templates and digital wax-up models were also exported and printed into resin diagnostic models for prosthodontic treatment after orthodontic treatment completed. The medians of scores of DP treatment plan and OP treatment plan were calculated and

  17. Surgical removal of coronal fragment of tooth embedded in lower lip and esthetic management of fractured crown segment.

    Science.gov (United States)

    Avinash, Alok; Dubey, Alok; Singh, Rajeev Kumar; Prasad, Swati

    2014-01-01

    Dental fractures of the permanent maxillary anterior teeth are relatively frequent accidents during childhood. The Efficient diagnosis and treatment of dental injury are important elements in clinical dentistry. This article describes a case of trauma in permanent right central maxillary incisors with tooth fragments embedded in the lower lip. Thorough clinical examination followed by soft tissue radiographs confirmed the presence of a fractured incisal fragment, which was surgically retrieved under local anesthesia. Direct composite restoration was placed. After finishing and polishing, an esthetic and natural-looking restoration was achieved; this completely satisfied the functional and esthetic expectation of the patient and dental team. How to cite this article: Avinash A, Dubey A, Singh RK, Prasad S. Surgical Removal of Coronal Fragment of Tooth Embedded in Lower Lip and Esthetic Management of Fractured Crown Segment. Int J Clin Pediatr Dent 2014;7(1):65-68.

  18. Perception of altered smile esthetics among Moroccan professionals and lay people.

    Science.gov (United States)

    Ousehal, L; Aghoutan, H; Chemlali, S; Anssari, I Filali; Talic, N

    2016-10-01

    To evaluate and compare the impact of altered smile characteristics on the perception of smile esthetics between Moroccan dentists and lay people. Thirty-four digital smile photographs displaying alterations in crown length and width, lateral incisor gingival margin position, gingival exposition, midline diastema, and upper midline deviation were presented to a sample of 30 dentists and 30 lay people. The ratings were assessed with a visual analog scale. Compared to that of lay people, Moroccan dentists' evaluation of the gingival smile was more critical when the decrease in central incisor crown length was 2.5 mm ( p  lay people similarly evaluated irregularities in the incisor gingival margin position. Increases in the midline diastema were judged critically by both Moroccan dentists and lay people. In this sample, Moroccan dentists evaluate smile esthetic alterations more critically than Moroccan lay people. This difference in perception of smile discrepancies must be taken into account during the finishing phases of orthodontic treatment and restoration of the anterior teeth in Moroccan patients.

  19. Is networking different with doctors working part-time? Differences in social networks of part-time and full-time doctors.

    Science.gov (United States)

    Heiligers, Phil J M; de Jong, Judith D; Groenewegen, Peter P; Hingstman, Lammert; Völker, Beate; Spreeuwenberg, Peter

    2008-10-04

    Part-time working is a growing phenomenon in medicine, which is expected to influence informal networks at work differently compared to full-time working. The opportunity to meet and build up social capital at work has offered a basis for theoretical arguments. Twenty-eight teams of medical specialists in the Netherlands, including 226 individuals participated in this study. Interviews with team representatives and individual questionnaires were used. Data were gathered on three types of networks: relationships of consulting, communication and trust. For analyses, network and multilevel applications were used. Differences between individual doctors and between teams were both analysed, taking the dependency structure of the data into account, because networks of individual doctors are not independent. Teams were divided into teams with and without doctors working part-time. Contrary to expectations we found no impact of part-time working on the size of personal networks, neither at the individual nor at the team level. The same was found regarding efficient reachability. Whereas we expected part-time doctors to choose their relations as efficiently as possible, we even found the opposite in intended relationships of trust, implying that efficiency in reaching each other was higher for full-time doctors. But we found as expected that in mixed teams with part-time doctors the frequency of regular communication was less compared to full-time teams. Furthermore, as expected the strength of the intended relationships of trust of part-time and full-time doctors was equally high. From these findings we can conclude that part-time doctors are not aiming at efficiency by limiting the size of networks or by efficient reachability, because they want to contact their colleagues directly in order to prevent from communication errors. On the other hand, together with the growth of teams, we found this strategy, focussed on reaching all colleagues, was diminishing. And our data

  20. Modeling wear of cast Ti alloys.

    Science.gov (United States)

    Chan, Kwai S; Koike, Marie; Okabe, Toru

    2007-05-01

    The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

  1. Part-time work among pediatricians expands.

    Science.gov (United States)

    Cull, William L; O'Connor, Karen G; Olson, Lynn M

    2010-01-01

    The objective of this study was to track trends in part-time employment among pediatricians from 2000 to 2006 and to examine differences within subgroups of pediatricians. As part of the Periodic Survey of Fellows, national random samples of American Academy of Pediatrics members were surveyed in 2000, 2003, and 2006. These surveys shared questions concerning working part-time and other practice characteristics. Roughly 1600 pediatricians were included in each random sample. Totals of 812 (51%), 1020 (63%), and 1013 (62%) pediatricians completed the surveys in 2000, 2003, and 2006, respectively. Analyses were limited to nonretired, posttrainee pediatricians. The number of pediatricians who reported that they work part-time increased from 15% in 2000, to 20% in 2003, to 23% in 2006. The pattern of increased part-time work from 2000 to 2006 held for many subgroups, including men, women, pediatricians who were younger than 40 years, pediatricians who were aged >or=50 years, pediatricians who worked in an urban inner city, pediatricians who worked in suburban areas, general pediatricians, and subspecialist pediatricians. Those who were working part-time were more satisfied within their professional and personal activities. Part-time pediatricians worked on average 14.3 fewer hours per week in direct patient care. Increases in part-time work are apparent throughout pediatrics. The possible continued growth of part-time is an important trend within the field of pediatrics that will need to be monitored.

  2. Wear of Spur Gears Having a Dithering Motion and Lubricated with a Perfluorinated Polyether Grease

    Science.gov (United States)

    Krantz, Timothy; Oswald, Fred; Handschuh, Robert

    2007-01-01

    Gear contact surface wear is one of the important failure modes for gear systems. Dedicated experiments are required to enable precise evaluations of gear wear for a particular application. The application of interest for this study required evaluation of wear of gears lubricated with a grade 2 perfluorinated polyether grease and having a dithering (rotation reversal) motion. Experiments were conducted using spur gears made from AISI 9310 steel. Wear was measured using a profilometer at test intervals encompassing 10,000 to 80,000 cycles of dithering motion. The test load level was 1.1 GPa maximum Hertz contact stress at the pitch-line. The trend of total wear as a function of test cycles was linear, and the wear depth rate was approximately 1.2 nm maximum wear depth per gear dithering cycle. The observed wear rate was about 600 times greater than the wear rate for the same gears operated at high speed and lubricated with oil.

  3. Hard- and soft-tissue contributions to the esthetics of the posed smile in growing patients seeking orthodontic treatment.

    Science.gov (United States)

    McNamara, Laurie; McNamara, James A; Ackerman, Marc B; Baccetti, Tiziano

    2008-04-01

    The purpose of this investigation was to broaden the understanding of how various skeletal, dental, and soft-tissue relationships are related to the esthetics of the smile in patients with malocclusions before orthodontic treatment. Images of the posed smile were captured from digital video clips of 60 growing patients (33 girls, 27 boys) seeking orthodontic treatment; they were judged by panels of laypersons and orthodontists. Discriminant analysis identified determinants of the "pleasing smile" from the results of a visual analog scale. Quantitative measurements of the soft and hard tissues were made by using the smile images, cephalometric radiographs, and study models. The esthetics of the smile were correlated with specific skeletal, dental, and soft-tissue structures in the anteroposterior, vertical, and transverse dimensions (Pearson test on non-topographic correlations). The esthetic smile judgments of orthodontists agreed with those of laypersons (r >0.93). The vertical thicknesses of the lips were the most significant component of a pleasant smile, for both the orthodontists (upper lip) and laypersons (lower lip) (discriminant power: 75%). The vertical thickness of the upper lip had a significant positive correlation with the position of the maxillary incisor. Vertical lip thickness proved to be the most influential variable in smile esthetics. The significant relationship of incisor protrusion with the vertical thickness of the vermilion border of the upper lip must be considered when planning orthodontic treatment.

  4. Prevalence of dental developmental anomalies of permanent teeth in children and their influence on esthetics.

    Science.gov (United States)

    Fekonja, Anita

    2017-07-08

    The aim of this study was to determine the prevalence of dental developmental anomalies in permanent teeth and their influence on esthetics. The records of 473 subjects, which comprised of orthopantomograms, clinical examination, and anamnestic data, were explored for dental developmental anomalies. Subjects with dental anomalies completed the modified questionnaire. Data on reasons for seeking the treatment as well as factors affecting the patients' satisfaction were collected. The data were processed using the Chi-square test. It was found that 79 subjects (16.7%) had at least 1 dental developmental anomaly. The most common anomalies were hypodontia (7.2%), followed by talon cusps (3.4%), and microdontia (2.5%). Hypodontia, microdontia, and talon cusps were found more prevalent in females than males, whereas hyperdontia and macrodontia were more common in males. The reason for dissatisfaction with their smile in most cases was due to missing teeth or spacing between anterior teeth (excess space 2.9 mm ± 1.1 mm), followed by crowding of anterior teeth (lack of space 3.1 mm ± 0.8mm), difficulty maintaining oral hygiene and midline asymmetry (1.8 mm ± 0.9 mm). All subjects were treated using a fixed orthodontic appliance and 30 (37.9%) of them had additional dental specialists included to achieve good esthetics and function. Overall, 92.4% of subjects were satisfied with their resulting appearance after treatment. Dental developmental anomalies are clinically evident abnormalities. They may be the cause of various dental problems and can influence esthetics and the development of orthodontic problems. This paper evaluates the distribution of dental developmental anomalies and their influence on esthetics and function. Careful observation and appropriate investigation are required to diagnose the condition and institute treatment. The therapeutic approach to some dental anomalies should be interdisciplinary. © 2017 Wiley Periodicals, Inc.

  5. A biological approach to crown fracture: Fracture reattachment - A report of two cases

    Directory of Open Access Journals (Sweden)

    K Vijayaprabha

    2012-01-01

    Full Text Available The development of adhesive dentistry has allowed dentists to use the patient′s own fragment to restore the fractured tooth, which is considered to be the most conservative method of treatment of crown fracture allowing restoration of original dental anatomy, thus rehabilitating function and esthetics in a short time by preserving dental tissues. The tooth fragment reattachment is preferred over full coverage crowns or composite resin restoration because it conserves sound tooth structure, and is more esthetic, maintaining the original anatomy and translucency, and the rate of incisal wear also matches that of original tooth structure. Presented here is a report of two cases of crown fracture managed by reattachment procedures.

  6. Wear and Degradation Modes in Selected Vehicle Tribosystems

    Directory of Open Access Journals (Sweden)

    G. Pantazopoulos

    2015-03-01

    Full Text Available The wear and degradation mechanisms of two principle vehicle tribosystems are presented to elucidate the main causes of their premature failure. The first case study concerns the malfunction of an automotive cast iron pressure plate operated in an automobile clutch system. The second is related to the unexpected failure of a stainless steel brake disk of a high performance motorcycle. Both components are designed to function under sliding friction conditions that lead to the severe wear of consumable non-metallic parts of the tribosystems: the clutch disk and the brake pad, respectively. However, in both cases it was the unexpected failure of the conjugate metallic parts that resulted in terminal system damage. The experimental approach to identify the root cause of failure involved both microstructure characterization, as well as observations of the metallic contact surfaces by means of optical and scanning electron microscopy, in conjunction with microhardness and surface topography measurements. For the case of the stainless steel brake disk in particular, Finite Element Analysis was employed to simulate the operating tribosystem, identify the site(s prone for crack initiation and validate the failure mechanisms hypotheses.

  7. Comparative short-term in vitro analysis of mutans streptococci adhesion on esthetic, nickel-titanium, and stainless-steel arch wires.

    Science.gov (United States)

    Kim, In-Hye; Park, Hyo-Sang; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub

    2014-07-01

    To test the hypothesis that there are no differences in mutans streptococci (MS) adhesion between esthetic and metallic orthodontic arch wires based on their surface characteristics. Surface roughness (Ra) and apparent surface free energy (SFE) were measured for six wires-four esthetic, one nickel-titanium (NiTi), and one stainless-steel (SS)-using profilometry and dynamic contact angle analysis, respectively. The amount of MS (Streptococcus mutans and Streptococcus sobrinus) adhering to the wires was quantified using the colony-counting method. The surfaces, coating layers, and MS adhesion were also observed by scanning electron microscopy. Statistical significance was set at P wires were significantly different from one another depending on the coating method (P wire showed the highest SFE, followed by the SS wire and then the four esthetic wires. The NiTi wires produced a significantly higher MS adhesion than did the SS wires (P wires showed significantly lower MS adhesions than did the NiTi wire (P < .05). Pearson correlation analyses found moderate significant positive correlations between the SFE and the S mutans and S sobrinus adhesions (r  =  .636/.427, P < .001/P  =  .001, respectively). The hypothesis is rejected. This study indicates that some esthetic coatings on NiTi alloy might reduce MS adhesion in vitro in the short term.

  8. Patient-Reported Esthetic and Functional Outcomes of Primary Total Laparoscopic Intestinal Vaginoplasty in Transgender Women With Penoscrotal Hypoplasia.

    Science.gov (United States)

    Bouman, Mark-Bram; van der Sluis, Wouter B; van Woudenberg Hamstra, Leonora E; Buncamper, Marlon E; Kreukels, Baudewijntje P C; Meijerink, Wilhelmus J H J; Mullender, Margriet G

    2016-09-01

    Puberty-suppressing hormonal treatment may result in penoscrotal hypoplasia in transgender women, making standard penile inversion vaginoplasty not feasible. For these patients, intestinal vaginoplasty is a surgical alternative, but knowledge on patient-reported postoperative outcomes and quality of life is lacking. To assess patient-reported functional and esthetic outcomes, quality of life, satisfaction, and sexual well-being after primary total laparoscopic intestinal vaginoplasty in transgender women. A survey study was performed on transgender women who underwent primary total laparoscopic intestinal vaginoplasty with at least 1 year of clinical follow-up. Thirty-one transgender women completed the questionnaires (median age at time of surgery = 19.1 years, range = 18.3-45.0) after a median clinical follow-up of 2.2 years (range = 0.8-7.5). Consenting women were asked to complete a combined questionnaire of the Subjective Happiness Scale, the Satisfaction With Life Scale, Cantril's Ladder of Life Scale, the Female Sexual Function Index, the Female Genital Self-Imaging Scale, the Amsterdam Hyperactive Pelvic Floor Scale-Women, and a questionnaire addressing postoperative satisfaction. Patient-reported functional and esthetic outcomes and postoperative quality of life. Patients graded their life satisfaction a median of 8.0 (range = 4.0-10.0) on Cantril's Ladder of Life Scale. Patients scored a mean total score of 27.7 ± 5.8 on the Satisfaction With Life Scale, which indicated high satisfaction with life, and a mean total score of 5.6 ± 1.4 on the Subjective Happiness Scale. Functionality was graded a median score of 8.0 of 10 (range = 1.0-10.0) and esthetics a score of 8.0 out of 10 (range = 3.0-10.0). The mean Female Sexual Function Index total score of sexually active transgender women was 26.0 ± 6.8. This group of relatively young transgender women reported satisfactory functional and esthetic results of the neovagina and a good quality of life

  9. New methodology for fast prediction of wheel wear evolution

    Science.gov (United States)

    Apezetxea, I. S.; Perez, X.; Casanueva, C.; Alonso, A.

    2017-07-01

    In railway applications wear prediction in the wheel-rail interface is a fundamental matter in order to study problems such as wheel lifespan and the evolution of vehicle dynamic characteristic with time. However, one of the principal drawbacks of the existing methodologies for calculating the wear evolution is the computational cost. This paper proposes a new wear prediction methodology with a reduced computational cost. This methodology is based on two main steps: the first one is the substitution of the calculations over the whole network by the calculation of the contact conditions in certain characteristic point from whose result the wheel wear evolution can be inferred. The second one is the substitution of the dynamic calculation (time integration calculations) by the quasi-static calculation (the solution of the quasi-static situation of a vehicle at a certain point which is the same that neglecting the acceleration terms in the dynamic equations). These simplifications allow a significant reduction of computational cost to be obtained while maintaining an acceptable level of accuracy (error order of 5-10%). Several case studies are analysed along the paper with the objective of assessing the proposed methodology. The results obtained in the case studies allow concluding that the proposed methodology is valid for an arbitrary vehicle running through an arbitrary track layout.

  10. Esthetic judgments of palatally displaced canines 3 months postdebond after surgical exposure with either a closed or an open technique.

    Science.gov (United States)

    Parkin, Nicola A; Freeman, Jennifer V; Deery, Chris; Benson, Philip E

    2015-02-01

    The aim of this study was to compare the esthetic judgments of orthodontists and laypeople regarding the appearance of palatally displaced canines 3 months after treatment with either a closed or an open surgical exposure and orthodontic alignment. A multicenter randomized controlled trial was undertaken in 3 hospitals in the United Kingdom. Patients with unilateral palatally displaced canines were randomly allocated to receive either a closed or an open surgical exposure. The teeth were aligned with fixed appliances, and 3 months after debond, intraoral photographs were taken. The photographs were projected in random order to 2 panels of judges (orthodontists and laypeople), who completed a questionnaire. The images of 67 participants (closed, 33; open, 34) were included. The laypeople were able to identify the operated tooth only 49.7% of the time (95% CI, 45.3%-54.0%); this was no better than chance (P = 0.880). The orthodontists were more successful but still identified the treated canine with certainty only 60.7% of the time (95% CI, 53.7%-67.8%; P = 0.003). Both panels more frequently assessed the unoperated canine to have a better appearance than the contralateral operated canine; however, there were no differences between the closed and open groups (proportion preferring unoperated canine-laypeople: closed, 58.7%; open, 57.0%; P = 0.43; and orthodontists: closed, 60.9%; open, 60.6%; P = 0.27). There is an esthetic impact to aligning a palatally displaced canine, but it is mostly minor and unlikely to be detectable by laypeople. The esthetic impact was the same, whether the canine was exposed with a closed or an open surgical technique. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  11. Creating Esthetic Harmony with Nonloading, Fixed Provisional Restoration using Extracted Teeth after Immediate Implant Placement.

    Science.gov (United States)

    Satwalekar, Parth; Satwalekar, Tanushree; Bondugula, Vasanthi; Bhuvaneshwari, B; Harshavardhan, K V; Pasula, Kiran

    2016-04-01

    To make use of fiber-reinforced composite and the patient's own extracted teeth in fabricating a provisional restoration following immediate implant placement. Fiber-reinforced composites offer various possibilities in temporization of osseointegrating implants in the esthetic zone. In this chairside technique, the patient's own extracted teeth with fiber-reinforced composite were used to fabricate a provisional restoration after immediate implant placement. A putty index was made before extracting the teeth and placing the implants as planned. The index and crowns of the extracted teeth were used to make a nonloading, esthetic, chair-side provisional restoration after immediate implant placement. By using the patient's own teeth for pro-visionalization immediately after implant placement, acceptance is greatly enhanced.

  12. Rat silicone hydrogel contact lens model: effects of high- versus low-Dk lens wear.

    Science.gov (United States)

    Zhang, Yunfan; Gabriel, Manal M; Mowrey-McKee, Mary F; Barrett, Ronald P; McClellan, Sharon; Hazlett, Linda D

    2008-11-01

    This study used a rat contact lens (CL) model to test if high- versus low-Dk lens wear caused changes in (1) conjunctival Langerhans cell (LC) number or location; (2) Bcl-2 expression; and (3) infection risk. Female, Lewis rats wore a high- or low-Dk CL continuously for 2 weeks. Afterward, corneas were harvested and processed for ADPase activity to identify LCs, for immunostaining and for real time-polymerase chain reaction. Contact lens-wearing rats also were challenged with Pseudomonas aeruginosa by placing a bacterial-soaked CL on the eye followed by topical delivery of bacteria. After 48 hrs, slit lamp examination and real time-polymerase chain reaction were used to evaluate the corneal response. Conjunctival LC were significantly increased after low- versus high-Dk CL wear (PDk lens wearing group. Bcl-2 mRNA levels were significantly decreased in low- versus high-Dk CL wearing rats, while Bax, FasL, caspase 3, and caspase 9 levels were unchanged. Immunostaining for Bcl-2 showed fewer positively stained epithelial cells in the low- versus high-Dk lens wearing group. After bacterial challenge, 30% of low- versus none of the high-Dk CL wearing corneas became infected and showed increased mRNA levels for several proinflammatory cytokines/chemokines, inducible nitric oxide synthase and matrix metalloproteinase-9. Low- versus high-Dk or non-CL wear led to an increased number of conjunctival LC, decreased Bcl-2 levels, and increased the risk of bacterial infection.

  13. Wear mechanism of CBN cutting tool during high-speed machining of mold steel

    International Nuclear Information System (INIS)

    Farhat, Z.N.

    2003-01-01

    Wear behavior of cubic boron nitride (CBN) cutting tool when cutting P20 tool steel was investigated. Oblique cutting tests were performed on a CNC lathe using five speeds, namely, 240, 600 and 1000 m min -1 . The CBN cutting tools were found to be superior to tungsten carbide (WC) tools. Fourfold increase in productivity and significant reduction in chipping and cratering was achieved for CBN as compared to WC. Wear, as the width of the wear land (VB), was monitored at selected time intervals; furthermore, topography of worn surfaces was performed, using a profilometer. Wear characterization of the rake and the flank surfaces as well as of the collected chips was conducted using a scanning electron microscopy (SEM), backscattered electron imaging and energy depressive X-ray (EDX). It was found that deformation in the chips occurs by localized shear deformation and the dominant wear mechanism at all speeds used was identified to be diffusive wear. At a 1000 m min -1 cutting speed, a secondary wear mechanism was identified, which is melt wear, i.e., formation of low melting point Cr and Mn compounds with the tool material and the subsequent ejection from the cutting zone

  14. Part-time jobs : What women want?

    NARCIS (Netherlands)

    Booth, A.L.; van Ours, J.C.

    2013-01-01

    Part-time jobs are common among partnered women in many countries. There are two opposing views on the efficiency implications of so many women working part-time. The negative view is that part-time jobs imply wastage of resources and underutilization of investments in human capital since many

  15. Wear mechanisms of Al2O3/TiC/Mo/Ni ceramic wire-drawing dies

    International Nuclear Information System (INIS)

    Deng Jianxin; Yang Xuefeng; Wang Jinghai

    2006-01-01

    Al 2 O 3 /TiC/Mo/Ni ceramic composites were produced by hot-pressing for the use of wire drawing dies. The fundamental properties of these ceramic die materials were examined. Wire drawing tests were carried out on the 65Mn steel wire with these ceramic dies. Finite element method (FEM) was used as a means of numerically evaluating stress and its distribution inside the ceramic drawing dies. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy (SEM). The wear mechanisms of the ceramic drawing dies were investigated. Detailed observations and analyses of the die wear surface have revealed that the most common failure of the ceramic drawing die is the wear at its approach zone. FEM analysis showed that the compressive stresses on both sides of the corners at the approach zone are higher than those of other parts of the ceramic drawing die. Abrasive and adhesive wear were found to be the predominant wear mechanisms through the whole approach zone owing to the greater compressive stresses. Examination of the center bore surface at the die bearing zone of the ceramic drawing dies demonstrated that the wear occurred by light abrasive, no adhesion wear was observed

  16. [Part-time residency training in Israel].

    Science.gov (United States)

    Fishbain, Dana; Levi, Baruch; Borow, Malke; Ashkenazi, Shai; Lindner, Arie

    2012-08-01

    Full-time work has long been perceived as a cornerstone of medical residency, the consensus being that a resident must apply the bulk of his time and attention to his professional training. Demographic and cultural changes that have taken place over the last several years, specifically the rise in the number of female doctors and the importance of leisure time to the younger generation, have intensified the need to find new and innovative ways to deal with the plight of the resident population. One idea, already in effect in many Western countries, is the institution of part-time residency programs. The possibility of fulfilling residency requirements on a part-time basis is intended to assist medical residents in integrating their professional development with their personal and family life, without compromising the quality of their training. A number of research studies conducted over the last several years in countries that allow part-time residency, among them the United States, England and Switzerland, aimed to examine the quality of part-time training. The various studies evinced a high level of satisfaction from the program both by the residents themselves and their supervisors, and in many aspects those doing residency part-time received higher appraisals than their full-time colleagues. Some of the residents polled noted that they would have totally foregone the practice of medicine had there not been an option to complete residency part-time. In light of the experience throughout the world and the changing landscape in Israel, the Scientific Council of the Israeli Medical Association decided to examine the issue and its various aspects, and weighed all the considerations in favor and against part-time residency. Recently, the Scientific Council approved the launch of a pilot program to allow part-time residency in several fields that were carefully selected according to specific criteria. Once the Ministry of Health completes the LegisLation process, part-time

  17. A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2009-11-01

    run for hundreds of hours in heavy-duty diesels provided insights into the kinds of complexity that the contact conditions in engines can produce, and suggested the physical basis for the current approach to modeling. The model presented here involves four terms, two representing the valve response and two for its mating seat material. The model's structure assumes that wear that takes place under a complex combination of plastic deformation, tangential shear, and oxidation. Tribolayers form, are removed, and may reform. Layer formation affects the friction forces in the interface, and in turn, the energy available to do work on the materials to cause wear. To provide friction data for the model at various temperatures, sliding contact experiments were conducted from 22 to 850 C in a pin-on-disk apparatus at ORNL. In order to account for the behavior of different materials and engine designs, parameters in all four terms of the model can be adjusted to account for wear-in and incubation periods before the dominant wear processes evolve to their steady-state rates. For example, the deformation rate is assumed to be maximum during the early stages of operation, and then, due to material work-hardening and the increase in nominal contact area (which reduces the load per unit area), decreases to a lower rate at long times. Conversely, the rate of abrasion increases with time or number of cycles due to the build-up of oxides and tribo-layers between contact surfaces. The competition between deformation and abrasion results in complex, non-linear behavior of material loss per cycle of operation. Furthermore, these factors are affected by valve design features, such as the angle of incline of the valve seat. Several modeling scenarios are presented to demonstrate how the wear profile versus number of cycles changes in response to: (a) different relative abrasion rates of the seat and valve materials, (b) the friction coefficient as a function of temperature, (c) the

  18. Do different vertical positions of maxillary central incisors influence smile esthetics perception?

    Science.gov (United States)

    Menezes, Erica Bretas Cabral; Bittencourt, Marcos Alan Vieira; Machado, Andre Wilson

    2017-01-01

    The purpose of this study was to determine the perception of smile esthetics among orthodontists and layperson, with respect to different maxillary central incisors vertical positions in full-face and close-up smile analyses. Frontal photographs of the smiles of two adult women were used. Images were altered to create a symmetrical image with the gingival margin levels of the maxillary canines matching the central incisors and a 1.0-mm central-to-lateral incisal step. Later, the images were altered in order to create six different central incisor vertical positions in 0.5-mm increments. The images were randomly assembled in an album, which was given to 114 judges, 57 orthodontists and 57 laypersons, who were asked to evaluate the attractiveness of the images using the visual analog scale. The data collected were statistically analyzed by means of 1-way analysis of variance with the Tukey post-hoc test and the Student t test. The highest rated smiles showed two notable characteristics: a) the central incisor gingival margins matched or were 0.5 mm below the line of the canine gingival margins and; b) the central-to-lateral incisal step was 1.0 to 1.5 mm. The worst smiles showed two notable characteristics: a) the central incisor gingival margins were 1.0 mm above or 1.5 mm below the canine gingival margins and; b) no step between the centrals and laterals or a 2.5-mm step. The vertical position of the maxillary central incisors significantly affected the perception of the smile esthetics, whereas slightly extruded central incisors were more esthetically preferred than intruded.

  19. Do different vertical positions of maxillary central incisors influence smile esthetics perception?

    Directory of Open Access Journals (Sweden)

    Erica Bretas Cabral Menezes

    Full Text Available ABSTRACT INTRODUCTION: The purpose of this study was to determine the perception of smile esthetics among orthodontists and layperson, with respect to different maxillary central incisors vertical positions in full-face and close-up smile analyses. METHODS: Frontal photographs of the smiles of two adult women were used. Images were altered to create a symmetrical image with the gingival margin levels of the maxillary canines matching the central incisors and a 1.0-mm central-to-lateral incisal step. Later, the images were altered in order to create six different central incisor vertical positions in 0.5-mm increments. The images were randomly assembled in an album, which was given to 114 judges, 57 orthodontists and 57 laypersons, who were asked to evaluate the attractiveness of the images using the visual analog scale. The data collected were statistically analyzed by means of 1-way analysis of variance with the Tukey post-hoc test and the Student t test. RESULTS: The highest rated smiles showed two notable characteristics: a the central incisor gingival margins matched or were 0.5 mm below the line of the canine gingival margins and; b the central-to-lateral incisal step was 1.0 to 1.5 mm. The worst smiles showed two notable characteristics: a the central incisor gingival margins were 1.0 mm above or 1.5 mm below the canine gingival margins and; b no step between the centrals and laterals or a 2.5-mm step. CONCLUSION: The vertical position of the maxillary central incisors significantly affected the perception of the smile esthetics, whereas slightly extruded central incisors were more esthetically preferred than intruded.

  20. Part-time Jobs : What Women Want?

    NARCIS (Netherlands)

    Booth, A.L.; van Ours, J.C.

    2010-01-01

    Part-time jobs are popular among partnered women in many countries. In the Netherlands the majority of partnered working women have a part-time job. Our paper investigates, from a supply-side perspective, if the current situation of abundant part-time work in the Netherlands is likely to be a

  1. Customized Cheek Plumper with Friction Lock Attachment for a Completely Edentulous Patient to Enhance Esthetics: A Clinical Report.

    Science.gov (United States)

    Bhushan, Prem; Aras, Meena A; Coutinho, Ivy; Rajagopal, Praveen; Mysore, Ashwin R; Kumar, Swati

    2017-01-25

    Prosthetic rehabilitation of a completely edentulous patient should never be restricted to the replacement of missing teeth. The ultimate aim of complete denture treatment should be restoration of the full range of oral functions and esthetics. Slumped cheeks are always a concern for esthetically demanding complete denture patients. This article describes a simple, scientific, cost-effective technique to improve facial esthetics in a completely edentulous patient with the help of a cheek plumper. The technique used here implements the concept of neutral zone to precisely determine the amount of space available for the cheek plumper. The simple friction lock attachments that retained the cheek plumpers on the prosthesis were also fabricated after determining the space available in the appropriate areas. Thus an effort was made to keep the cheek plumpers unobtrusive yet effective to ensure complete integration of the prosthesis into the stomatognathic system. © 2017 by the American College of Prosthodontists.

  2. Wear Behavior of Medium Carbon Steel with Biomimetic Surface Under Starved Lubricated Conditions

    Science.gov (United States)

    Zhang, Zhihui; Shao, Feixian; Liang, Yunhong; Lin, Pengyu; Tong, Xin; Ren, Luquan

    2017-07-01

    Friction and wear under starved lubrication condition are both key life-related factors for mechanical performance of many structural parts. In this paper, different surface morphologies on medium carbon steel were fabricated using laser, inspired by the surface coupling effect of biological system. The friction and sliding wear behaviors of biomimetic specimens (characterized by convex and concave units on the specimen surface) were studied under starved lubrication condition. The stress distribution on different sliding surfaces under sliding friction was studied using finite element method. The results showed that the tribological performance of studied surfaces under starved lubrication condition depended not only on the surface morphology but also on the structure of biomimetic units below surface (subsurface structure). The friction coefficient of biomimetic surface was effectively reduced by the concave unit depth, while the refined microstructure with higher hardness led to the much better wear resistance. In addition to lubricant reserving and wear debris trapping effect derived from the surface concave morphology, it was believed that the well-formed subsurface structure of biomimetic units could carry much heavy loads against tribopair, which enhanced the function of surface topography and resulted in complementary lubrication in the wear contact area. The uniform stress distribution on the entire biomimetic surface also played an important role in stabilizing the friction coefficient and reducing the wear cracks.

  3. Improving esthetic results in benign parotid surgery: statistical evaluation of facelift approach, sternocleidomastoid flap, and superficial musculoaponeurotic system flap application.

    Science.gov (United States)

    Bianchi, Bernardo; Ferri, Andrea; Ferrari, Silvano; Copelli, Chiara; Sesenna, Enrico

    2011-04-01

    The purpose of this article was to analyze the efficacy of facelift incision, sternocleidomastoid muscle flap, and superficial musculoaponeurotic system flap for improving the esthetic results in patients undergoing partial parotidectomy for benign parotid tumor resection. The usefulness of partial parotidectomy is discussed, and a statistical evaluation of the esthetic results was performed. From January 1, 1996, to January 1, 2007, 274 patients treated for benign parotid tumors were studied. Of these, 172 underwent partial parotidectomy. The 172 patients were divided into 4 groups: partial parotidectomy with classic or modified Blair incision without reconstruction (group 1), partial parotidectomy with facelift incision and without reconstruction (group 2), partial parotidectomy with facelift incision associated with sternocleidomastoid muscle flap (group 3), and partial parotidectomy with facelift incision associated with superficial musculoaponeurotic system flap (group 4). Patients were considered, after a follow-up of at least 18 months, for functional and esthetic evaluation. The functional outcome was assessed considering the facial nerve function, Frey syndrome, and recurrence. The esthetic evaluation was performed by inviting the patients and a blind panel of 1 surgeon and 2 secretaries of the department to give a score of 1 to 10 to assess the final cosmetic outcome. The statistical analysis was finally performed using the Mann-Whitney U test for nonparametric data to compare the different group results. P less than .05 was considered significant. No recurrence developed in any of the 4 groups or in any of the 274 patients during the follow-up period. The statistical analysis, comparing group 1 and the other groups, revealed a highly significant statistical difference (P esthetic results in benign parotid surgery. The evaluation of functional complications and the recurrence rate in this series of patients has confirmed that this technique can be safely

  4. Effect of work material composition on the wear life of TiN-coated tools

    Energy Technology Data Exchange (ETDEWEB)

    Harju, E. [Helsinki Univ. of Technol., Espoo (Finland). Dept. of Materials Science and Engineering; Korhonen, A.S. [Helsinki Univ. of Technol., Espoo (Finland). Dept. of Materials Science and Engineering; Jiang Laizhu [Dept. of Mechanical Engineering, Helsinki Univ. of Technology, Espoo (Finland); Ristolainen, E. [Centre for Chemical Analysis, Helsinki Univ. of Technology, Espoo (Finland)

    1996-11-15

    Three commercially available quenched and tempered steels corresponding approximately to AISI 4140 were compared in dry turning using both uncoated and TiN-coated high-speed steel (HSS) inserts. Of three steels A, B and C, steel A did not contain added calcium, while both B and C were calcium-treated. In dry turning with uncoated HSS inserts steel B was best. It gave over 2 times longer wear life than steel A and 1 1/2 times longer than steel C. When the inserts were coated with TiN, the cutting speed could be increased and the order of performance changed dramatically. Steel C was then best, giving nearly 26 times longer wear life than steel A and 9 times longer wear life than steel B. Based on secondary ion mass spectroscopy measurements, the enrichment of alloying elements was studied on the tool surface. The formation of an adherent protective layer on the rake face during turning of steel C is proposed as a mechanism explaining the observed differences in wear lives. (orig.)

  5. Effect of work material composition on the wear life of TiN-coated tools

    International Nuclear Information System (INIS)

    Harju, E.; Ristolainen, E.

    1996-01-01

    Three commercially available quenched and tempered steels corresponding approximately to AISI 4140 were compared in dry turning using both uncoated and TiN-coated high-speed steel (HSS) inserts. Of three steels A, B and C, steel A did not contain added calcium, while both B and C were calcium-treated. In dry turning with uncoated HSS inserts steel B was best. It gave over 2 times longer wear life than steel A and 1 1/2 times longer than steel C. When the inserts were coated with TiN, the cutting speed could be increased and the order of performance changed dramatically. Steel C was then best, giving nearly 26 times longer wear life than steel A and 9 times longer wear life than steel B. Based on secondary ion mass spectroscopy measurements, the enrichment of alloying elements was studied on the tool surface. The formation of an adherent protective layer on the rake face during turning of steel C is proposed as a mechanism explaining the observed differences in wear lives. (orig.)

  6. A long-term laboratory test on staining susceptibility of esthetic composite resin materials

    NARCIS (Netherlands)

    Ardu, S.; Braut, V.; Gutemberg, D.; Krejci, I.; Dietschi, D.; Feilzer, A.J.

    2010-01-01

    Objective: To evaluate the color stability of composite resin types designed for esthetic anterior restorations when continuously exposed to various staining agents. Method and Materials: Thirty-six disk-shaped specimens were made of each of 12 composite materials (1 microfilled and 11 hybrid

  7. The model of the dependence of the abrasive wear value on the maximal linear wear

    Directory of Open Access Journals (Sweden)

    О.А. Вишневський

    2004-01-01

    Full Text Available  The relation of the contact area of the rubber roll with a sample and the maximal linear wear value is found. The mathematical model of the dependence of the wear volume weight value on the maximal dimple depth is presented with the friction on abrasive particles fixed nonrigidly. The relation of volume weight wear with the rubber roll contact surface area with a sample with the friction on abrasive particles fixed nonrigidly is established.

  8. Part-time labour in retailing

    NARCIS (Netherlands)

    A.R. Thurik (Roy); N. van der Wijst (Nico)

    1984-01-01

    textabstractRetailers have to deal with a fluctuating demand for labor. The use of part-time employees is one of their instruments to cope with these fluctuations. This article gives theoretical considerations regarding the use of part-time labor in the retail trade and empirical evidence regarding

  9. Some Aspects of Part-Time Work.

    Science.gov (United States)

    Australian Dept. of Labour and National Service, Melbourne. Women's Bureau.

    Of major importance to many married women seeking employment in Australia is the availability of part-time work. To describe the economic aspects of part-time employment for women, a review was made of statistics published by the Commonwealth Bureau of Census and Statistics and of research on part-time employment in overseas countries, and a…

  10. Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

    Science.gov (United States)

    Teeter, Matthew G.; Seslija, Petar; Milner, Jaques S.; Nikolov, Hristo N.; Yuan, Xunhua; Naudie, Douglas D. R.; Holdsworth, David W.

    2013-05-01

    An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements.

  11. Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

    International Nuclear Information System (INIS)

    Teeter, Matthew G; Naudie, Douglas D R; Holdsworth, David W; Seslija, Petar; Milner, Jaques S; Nikolov, Hristo N; Yuan Xunhua

    2013-01-01

    An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm 3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements. (paper)

  12. Esthetic Rehabilitation in a Patient with Mesiodens

    Directory of Open Access Journals (Sweden)

    Leena Verma

    2012-01-01

    Full Text Available Supernumerary tooth is one that is additional to the normal series and can be found in almost any region of the dental arch. They may be single, multiple, unilateral or bilateral erupted or unerupted and in one or both jaws. Mesiodens is the most common type of supernumerary tooth found in the premaxilla between two central incisors. Presented here is a case of ten year old male child with supplemental mesiodens with talons cusp erupted in the oral cavity causing malocclusion and an another horizontally impacted mesiodens near the nasal floor. Mesiodens was extracted and esthetic reconstruction of the patient was done by bringing left maxillary central incisor to correct position by orthodontic treatment.

  13. Thin Layer Activation (TLA) Analysis for Wear Study of Automotive Component

    International Nuclear Information System (INIS)

    Hendiko, E.B.; Nur, M.; Priyono; Suryanto; Silakhuddin

    2000-01-01

    The measurement of surface losses of motor cycle piston ring, the automotive component was carried out. The piston ring is activated by proton beam from cyclotron with energy 12.5 MeV and beam current 1 μA for 30 minutes. The piston ring was installed to the machine and then operated for several times. The method to measured surface loss of piston ring due to wear by concentration, i.e. measured the activity of wear products in the lubricant oil with gamma spectrometry. The measurement the depth layer surface losses used the calibration curve from The Calibration Software Wear, Corrosion And Degradation Monitoring With TLA by Utaja of Iron (Fe) foil was activated by energy proton 12.5 MeV. The surface losses level of piston ring to be 50 hours operated was be 45.0 μm before half-life time correction and 57.0 μm after half-life time correction, its corresponding with count rate lubricant oil activity is 9.04 x 10 -4 μCi before half-life time correction and 1.12 x 10 -3 μCi after half-life time correction. (author)

  14. Quantitive dynamical wear analysis and the convergent quest for significant wear reduction

    International Nuclear Information System (INIS)

    Sellschop, F.; Kirsch, J.; Derry, T.; Marcus, R.

    1984-01-01

    The maturing of nuclear physics has made the development of ion beam modification of materials possible, bringing new skills and prospects to the world of materials science. In the following paper an outline is given of the history of ion beam modification of materials (IBMM) and its use for altering the surface of metals to combat wear and friction, and monitoring wear in engines

  15. Q-sort assessment vs visual analog scale in the evaluation of smile esthetics.

    Science.gov (United States)

    Schabel, Brian J; McNamara, James A; Franchi, Lorenzo; Baccetti, Tiziano

    2009-04-01

    This study was designed to compare the reliability of the Q-sort and visual analog scale (VAS) methods for the assessment of smile esthetics. Furthermore, agreement between orthodontists and parents of orthodontic patients, and between male and female raters, was assessed in terms of subjective evaluation of the smile. Clinical photographs and digital video captures of 48 orthodontically treated patients were rated by 2 panels: 25 experienced orthodontists (15 men, 10 women) and 20 parents of the patients (8 men, 12 women). Interrater reliability of the Q-sort and VAS methods was evaluated by using single-measure and average-measure intraclass correlation (ICC). Kappa agreement and the McNemar test were used to evaluate agreement between orthodontists and parents, and between men and women, for "attractive" and "unattractive" images of smiles captured with clinical photography. The single-measure ICC coefficients showed fair to good reliability of the Q-sort and poor reliability of the VAS for measuring esthetic preferences of an individual orthodontist or parent. Both rating groups agreed significantly (P >0.05) on the total percentage of "attractive" images of smiles captured with clinical photography. Men and women, however, significantly disagreed on the total percentages of "attractive" and "unattractive" smiles. Women rated higher percentages of both image groups as "attractive" than did their male counterparts. The Q-sort was more reliable than the VAS for measuring smile esthetics. Orthodontists and parents of orthodontic patients agreed with respect to "attractive" and "unattractive" smiles. Men and women agreed poorly with respect to "attractive" and "unattractive" smiles.

  16. A probabilistic-based approach to monitoring tool wear state and assessing its effect on workpiece quality in nickel-based alloys

    Science.gov (United States)

    Akhavan Niaki, Farbod

    The objective of this research is first to investigate the applicability and advantage of statistical state estimation methods for predicting tool wear in machining nickel-based superalloys over deterministic methods, and second to study the effects of cutting tool wear on the quality of the part. Nickel-based superalloys are among those classes of materials that are known as hard-to-machine alloys. These materials exhibit a unique combination of maintaining their strength at high temperature and have high resistance to corrosion and creep. These unique characteristics make them an ideal candidate for harsh environments like combustion chambers of gas turbines. However, the same characteristics that make nickel-based alloys suitable for aggressive conditions introduce difficulties when machining them. High strength and low thermal conductivity accelerate the cutting tool wear and increase the possibility of the in-process tool breakage. A blunt tool nominally deteriorates the surface integrity and damages quality of the machined part by inducing high tensile residual stresses, generating micro-cracks, altering the microstructure or leaving a poor roughness profile behind. As a consequence in this case, the expensive superalloy would have to be scrapped. The current dominant solution for industry is to sacrifice the productivity rate by replacing the tool in the early stages of its life or to choose conservative cutting conditions in order to lower the wear rate and preserve workpiece quality. Thus, monitoring the state of the cutting tool and estimating its effects on part quality is a critical task for increasing productivity and profitability in machining superalloys. This work aims to first introduce a probabilistic-based framework for estimating tool wear in milling and turning of superalloys and second to study the detrimental effects of functional state of the cutting tool in terms of wear and wear rate on part quality. In the milling operation, the

  17. effect of turning parameters on metal removal and tool wear rates

    African Journals Online (AJOL)

    user

    2 SCHOOL OF AEROSPACE, TRANSPORT AND MANUFACTURING, CRANFIELD UNIV., ... AISI 1018 low carbon steel during turning operation to reduce tooling costs as a result of tool wear and achieve optimum metal ... performance of a system, part or component while ... traditional and experimental design methods of.

  18. Experiences in applying surface activation and the thin-layer difference method in comparative wear measurements of motor car components

    International Nuclear Information System (INIS)

    Sturm, H.

    1981-01-01

    On the basis of wear studies of valve rockers and valves of diesel engines the radiometric methods applied are presented. Measuring requirements to be met are discussed. Evaluation of the results ranges from determination of wear depths to standardized and specific wear intensities. The latter may be used for comparing wear rates under any conditions at any times, for determining the most important wear mechanisms and for taking measures aimed at improving the wear behaviour

  19. Plasma nitrocarburizing process - a solution to improve wear and corrosion resistance

    International Nuclear Information System (INIS)

    Joseph, Alphonsa J.; Ghanshyam, J.; Mukherjee, S.

    2015-01-01

    To prevent wear and corrosion problems in steam turbines, coatings have proved to have an advantage of isolating the component substrate from the corrosive environment with minimal changes in turbine material and design. Diffusion based coatings like plasma nitriding and plasma nitrocarburizing have been used for improving the wear and corrosion resistance of components undergoing wear during their operation. In this study plasma nitrocarburizing process was carried out on ferritic alloys like ASTM A182 Grade F22 and ATM A105 alloy steels and austenitic stainless steels like AISI 304 and AISI 316 which are used to make trim parts of control valves used for high pressure and high temperature steam lines to enhance their wear and corrosion resistance properties. The corrosion rate was measured by a potentiodynamic set up and salt spray unit in two different environments viz., tap water and 5% NaCl solutions. The Tafel plots of ferritic alloys and austenitic stainless steels show that plasma nitrocarburizing process show better corrosion resistance compared to that of the untreated steel. It was found that after plasma nitrocarburizing process the hardness of the alloy steels increased by a factor of two. The corrosion resistance of all the steels mentioned above improved in comparison to the untreated steels. This improvement can be attributed to the nitrogen and carbon incorporation in the surface of the material. This process can be also applied to components used in nuclear industries to cater to the wear and corrosion problems. (author)

  20. Identification of the neural correlates of cyclothymic temperament using an esthetic judgment for paintings task in fMRI.

    Science.gov (United States)

    Mizokami, Yoshinori; Terao, Takeshi; Hatano, Koji; Kodama, Kensuke; Kohno, Kentaro; Makino, Mayu; Hoaki, Nobuhiko; Araki, Yasuo; Izumi, Toshihiko; Shimomura, Tsuyoshi; Fujiki, Minoru; Kochiyama, Takanori

    2014-12-01

    There is a well-known association between artistic creativity and cyclothymic temperament but the neural correlates of cyclothymic temperament have not yet been fully identified. Recently, we showed that the left lingual gyrus and bilateral cuneus may be associated with esthetic judgment of representational paintings, we therefore sought to investigate brain activity during esthetic judgment of paintings in relation to measures of cyclothymic temperament. Regions of interest (ROI) were set at the left lingual gyrus and bilateral cuneus using automated anatomical labeling, and percent signal changes of the ROIs were measured by marsbar toolbox. The associations between percent signal changes of the ROIs during esthetic judgments of paintings and cyclothymic temperament scores were investigated by Pearson׳s coefficient. Moreover, the associations were further analyzed using multiple regression analysis whereby cyclothymic temperament scores were a dependent factor and percent signal changes of the 3 ROIs and the other 4 temperament scores were independent factors. There was a significantly negative association of cyclothymic temperament scores with the percent signal changes of the left lingual gyrus during esthetic judgments of paintings, but not with those of bilateral cuneus. Even after adjustment using multiple regression analysis, this finding remained unchanged. The number of subjects was relatively small and the task was limited to appreciation of paintings. The present findings suggest that cyclothymic temperament may be associated with the left lingual gyrus. Copyright © 2014 Elsevier B.V. All rights reserved.