DENTAL MATERIAL BIOCOMPATIBILITY: A CROSS-SECTIONAL STUDY

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Carmen SAVIN

2017-06-01

Full Text Available The aim of this study is to assess the knowledge of the students in the Faculty of Dental Medicine of Iasi on the biocompatibility of the dental materials used in current practice. To this end, we elaborated our own questionnaire, including 10 questions to which 92 students from the last 2 years of study answered. The questionnaire cotains assertions on the potential toxic reactions of the most frequently used dental materials. The students answered correctly to the questions related to the biocompatibility of certain dental materials, such as glass-ionomer cement and calcium hydroxide, and they recognized that allergic reactions determined by acrylic resins may occur. We also noticed the lack of knowledge referring to the irreversible modifications produced by the tooth whitening substances on the enamel and dentin, as well as to the side effects produced by dental amalgam.

Advances in dental materials.

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Fleming, Garry J P

2014-05-01

The dental market is replete with new resorative materials marketed on the basis of novel technological advances in materials chemistry, bonding capability or reduced operator time and/or technique sensitivity. This paper aims to consider advances in current materials, with an emphasis on their role in supporting contemporary clinical practice.

Investigation of contact allergy to dental materials by patch testing

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Reena Rai

2014-01-01

Full Text Available Background: Dental products are widely used by patients and dental personnel alike and may cause problems for both. Dental materials could cause contact allergy with varying manifestations such as burning, pain, stomatitis, cheilitis, ulcers, lichenoid reactions localized to the oral mucosa in patients, and hand dermatitis in dental personnel. Patch testing with the dental series comprising commonly used materials can be used to detect contact allergies to dental materials. Aim: This study aimed to identify contact allergy among patients who have oral mucosal lesions after dental treatment and among dental personnel who came in contact with these materials. Materials and Methods: Twenty patients who had undergone dental procedures with symptoms of oral lichen planus, oral stomatitis, burning mouth, and recurrent aphthosis, were included in the study. Dental personnel with history of hand dermatitis were also included in the study. Patch testing was performed using Chemotechnique Dental Series and results interpreted as recommended by the International Contact Dermatitis Research Group (ICDRG. Results: Out of 13 patients who had undergone dental treatment/with oral symptoms, six patients with stomatitis, lichenoid lesions, and oral ulcers showed positive patch tests to a variety of dental materials, seven patients with ulcers had negative patch tests, seven dental personnel with hand dermatitis showed multiple allergies to various dental materials, and most had multiple positivities. Conclusion: The patch test is a useful, simple, noninvasive method to detect contact allergies among patients and among dental personnel dealing with these products. Long term studies are necessary to establish the relevance of these positive patch tests by eliminating the allergic substances, identifying clinical improvement, and substituting with nonallergenic materials.

[Dental implant restoration abutment selection].

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Bin, Shi; Hao, Zeng

2017-04-01

An increasing number of implant restoration abutment types are produced with the rapid development of dental implantology. Although various abutments can meet different clinical demands, the selection of the appropriate abutment is both difficult and confusing. This article aims to help clinicians select the appropriate abutment by describing abutment design, types, and selection criteria.

Anisotropic local physical properties of human dental enamel in comparison to properties of some common dental filling materials.

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Raue, Lars; Hartmann, Christiane D; Rödiger, Matthias; Bürgers, Ralf; Gersdorff, Nikolaus

2014-11-01

A major aspect in evaluating the quality of dental materials is their physical properties. Their properties should be a best fit of the ones of dental hard tissues. Manufacturers give data sheets for each material. The properties listed are characterized by a specific value. This assumes (but does not prove) that there is no direction dependence of the properties. However, dental enamel has direction-dependent properties which additionally vary with location in the tooth. The aim of this paper is to show the local direction dependence of physical properties like the elastic modulus or the thermal expansion in dental hard tissues. With this knowledge the 'perfect filling/dental material' could be characterized. Enamel sections of ∼400-500 μm thickness have been cut with a diamond saw from labial/buccal to palatal/lingual (canine, premolar and molar) and parallel to labial (incisor). Crystallite arrangements have been measured in over 400 data points on all types of teeth with x-ray scattering techniques, known from materials science. X-ray scattering measurements show impressively that dental enamel has a strong direction dependence of its physical properties which also varies with location within the tooth. Dental materials possess only little or no property direction dependence. Therefore, a mismatch was found between enamel and dental materials properties. Since dental materials should possess equal (direction depending) properties, worthwhile properties could be characterized by transferring the directional properties of enamel into a property 'wish list' which future dental materials should fulfil. Hereby the 'perfect dental material' can be characterized.

The Historical Evolution of Dental Impression Materials.

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Papadiochos, Ioannis; Papadiochou, Sofia; Emmanouil, Ioannis

The concept of impression making process in dentistry began in the mid 1800s. Dentists realized that the construction of a prosthetic restoration required both a detailed capture of the oral tissues along with stone cast fabrications. To accomplish these goals, impression materials were essential. Beeswax represents the first impression material, while important bechmarks during the historical evolution of dental impression materials are considered to be the introduction of dental trays in the early 1800s and the invention of the gutta-percha, thermoplastic resins and plaster of Paris. The double (corrective) impression technique, along with the functional impression concept that was established after mid 1800s, are also identified as pivotal innovations. During the 20th century, the advances in material development slowed significantly since the majority of the current impression materials had already been invented. However, the introduction of elastomeric impression materials in the field of prosthodontics that offered the advantages of accuracy and dimensional stability substantially upgraded both the impression accuracy and the quality of the final restoration. Presently, the dental practitioner has access to a variety of impression materials and should be aware of their properties, indications and limitations as well. Futhermore, while continuous attempts are being made to enhance these materials, the ideal impression material has yet to be developed. The purpose of this article was to provide a comprehensive review about the historical development of impression dental materials. Copyright American Academy of the History of Dentistry.

Mechanical behaviour of dental composite filling materials using digital holography

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Monteiro, J.M.; Lopes, H.; Vaz, M.A.P.; Campos, J.C. Reis

2010-01-01

One of the most common clinical problems in dentistry is tooth decay. Among the dental filling materials used to repair tooth structure that has been destroyed by decay are dental amalgam and composite materials based on acrylics. Dental amalgam has been used by dentists for the past 150 years as a dental restorative material due to its low cost, ease of application, strength, durability, and bacteriostatic effects. However its safety as a filling material has been questioned due to th...

Evaluation of patients with oral lichenoid lesions by dental patch testing and results of removal of the dental restoration material

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Emine Buket Şahin

2016-12-01

Full Text Available Background and Design: Oral lichenoid lesions (OLL are contact stomatitis characterized by white reticular or erosive patches, plaque-like lesions that are clinically and histopathologically indistinguishable from oral lichen planus (OLP. Amalgam dental fillings and dental restoration materials are among the etiologic agents. In the present study, it was aimed to evaluate the standard and dental series patch tests in patients with OLL in comparison to a control group and evaluate our results. Materials and Methods: Thirty-three patients with OLL or OLP and 30 healthy control subjects, who had at least one dental restoration material and/or dental filling, were included in the study. Both groups received standard series and dental patch test and the results were evaluated simultaneously. Results: The most frequent allergens in the dental series patch test in the patient group were palladium chloride (n=4; 12.12% and benzoyl peroxide (n=2, 6.06%. Of the 33 patients with OLL; 8 had positive reaction to allergents in the standard patch test series and 8 had positive reaction in the dental patch test series. There was no significant difference in the rate of patch test reaction to the dental and standard series between the groups. Ten patients were advised to have the dental restoration material removed according to the results of the patch tests. The lesions improved in three patients [removal of all amalgam dental fillings (n=1, replacement of all amalgam dental fillings with an alternative filling material (n=1 and replacement of the dental prosthesis (n=1] following the removal or replacement of the dental restoration material. Conclusion: Dental patch test should be performed in patients with OLL and dental restoration material. Dental filling and/or prosthesis should be removed/replaced if there is a reaction against a dental restoration material-related allergen.

Role of dental restoration materials in oral mucosal lichenoid lesions

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Rajneesh Sharma

2015-01-01

Full Text Available Background: Dental restorative materials containing silver-mercury compounds have been known to induce oral lichenoid lesions. Objectives: To determine the frequency of contact allergy to dental restoration materials in patients with oral lichenoid lesions and to study the effect of removal of the materials on the lesions. Results: Forty-five patients were recruited in three groups of 15 each: Group A (lesions in close contact with dental materials, Group B (lesions extending 1 cm beyond the area of contact and Group C (no topographic relationship. Thirty controls were recruited in two groups of 15 individuals each: Group D (oral lichenoid lesions but no dental material and Group E (dental material but no oral lichenoid lesions. Patch tests were positive in 20 (44.5% patients. Mercury was the most common allergen to elicit a positive reaction in eight patients, followed by nickel (7, palladium (5, potassium dichromate (3, balsam of Peru, gold sodium thiosulphate 2 and tinuvin (2 and eugenol (1, cobalt chloride (1 and carvone (1. Seven patients elicited positive response to more than one allergen. In 13 of 20 patients who consented to removal of the dental material, complete healing was observed in 6 (30%, marked improvement in 7 (35% and no improvement in 7 (35% patients. Relief of symptoms was usually observed 3 months after removal. Limitations: Limited number of study subjects and short follow up after removal/replacement of dental restoration materials are the main limitations of this study. Conclusion: Contact allergy to amalgam is an important etiologic factor in oral lichenoid lesions and removal of restorative material should be offered to patients who have lesions in close proximity to the dental material.

Developing a flexible core Dental Public Health curriculum for predoctoral dental and dental hygiene schools.

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Atchison, Kathryn; Mascarenhas, Ana Karina; Bhoopathi, Vinodh

2015-01-01

The curriculum for graduating dental and dental hygiene students must prepare them to contribute to the improvement or maintenance of health for individual patient's and the public's health. The objective is to describe the background for and the process used to develop a core Dental Public Health Curriculum for such students. The process used was to solicit and review existing dental public health curriculum in dental and dental hygiene schools; review curriculum for other health professionals; identify the themes needed to frame the curriculum; select usable materials and identify gaps in existing curricular materials; and develop appropriate curriculum materials that would embody the competencies developed for undergraduate dental and dental hygiene education. Twenty-three topics were identified as embodying the eight competencies. Based on these topics, six courses, Principles of Dental Public Health, Evidence-Based Dentistry, Ethics and Dental Public Health, Dental Public Health Policy and Advocacy, Oral Health Promotion and Disease Prevention, and Oral Health Literacy and Dental Public Health, were prepared. Each course includes syllabus, PowerPoint presentations, student assignments and activities, instructor guide, and classroom discussion points. Depending on the hours available in the existing curriculum at the dental or hygiene school, lecture presentations and take home assignments/discussions may be used independently or in combination with presentations from other courses. In addition, individual discussions and activities may be used to integrate dental public health materials into other courses. A flexible curriculum is available at the AAPHD website to enable the incorporation of DPH topics into the curriculum. © 2015 American Association of Public Health Dentistry.

[Influence of the fluoride releasing dental materials on the bacterial flora of dental plaque].

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Płuciennik, Małgorzata; Sakowska, Danuta; Krzemiński, Zbigniew; Piatowska, Danuta

2008-01-01

The assessment of influence of silver-free, fluor releasing dental materials on dental plaque bacteria quantity. 17 patients were included into the study. 51 restorations were placed following manufacturers recommendations. Following materials were used: conventional glassionomer Ketac-Molar ESPE, resin modified glassionomer Fuji II LC GC and fluor containing composite Charisma Heraeus Kulzer Class V restorations were placed in following teeth of upper and lower jaw: canines, first bicuspids, second bicuspids. Sound enamel was a control. After 10 weeks the 72 hours old dental plaque was collected from surface of restorations and control using sterile probe. Total amount of 68 dental plaques were investigated. Each plaque was placed on scaled and sterile aluminum foil. The moist weight of dental plaque was scaled. Dental plaque was moved into 7 ml 0.85% NaCl solution reduced by cystein chlorine hydrogen and disintegrated by ultrasounds (power:100 Watt, wave amplitude: 5 micorm). The suspension of dental plaque was serially diluted from 10(-4) to 10(-5) in sterile 0,85% NaCl solution, and seeded with amount of 0.1 ml on appropriate base. In dental plaque trials the amount of cariogenic bacteria was calculated--Streptococcus mutans, Streptococcus, Lactobacillus, Veillonella and Neisseria, and also total amount of aerobic and anaerobic bacteria was measured. Microbiologic studies were performed in Institute of Microbiology, Medical University, Łódź. Statistical analysis of collected data was accomplished. In 72 hours old dental plaques collected from the surfaces of Ketac -Molar, Fuji II LC, Charisma after 10 weeks since being placed into the class V cavity, results show no statistically significant differences in the amount of Streptococcus mutans, Streptococcus spp., Lactobacillus spp., Veillonella spp., Neisseria spp, in total amount of aerobic and anaerobic bacteria and in the quantity proportion of Streptococcus mutans versus Streptococcus spp. in comparison

Dentist Material Selection for Single-Unit Crowns: Findings from The National Dental Practice-Based Research Network

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Makhija, Sonia K.; Lawson, Nathaniel C.; Gilbert, Gregg H.; Litaker, Mark S.; McClelland, Jocelyn A.; Louis, David R.; Gordan, Valeria V.; Pihlstrom, Daniel J.; Meyerowitz, Cyril; Mungia, Rahma; McCracken, Michael S.

2016-01-01

Objectives Dentists enrolled in the National Dental Practice-Based Research Network completed a study questionnaire about techniques and materials used for single-unit crowns and an enrollment questionnaire about dentist/practice characteristics. The objectives were to quantify dentists’ material recommendations and test the hypothesis that dentist’s and practice’s characteristics are significantly associated with these recommendations. Methods Surveyed dentists responded to a contextual scenario asking what material they would use for a single-unit crown on an anterior and posterior tooth. Material choices included: full metal, porcelain-fused-to-metal (PFM), all-zirconia, layered zirconia, lithium disilicate, leucite-reinforced ceramic, or other. Results 1,777 of 2,132 eligible dentists responded (83%). The top 3 choices for anterior crowns were lithium disilicate (54%), layered zirconia (17%), and leucite-reinforced glass ceramic (13%). There were significant differences (p<0.05) by dentist’s gender, race, years since graduation, practice type, region, practice busyness, hours worked/week, and location type. The top 3 choices for posterior crowns were all-zirconia (32%), PFM (31%), and lithium disilicate (21%). There were significant differences (p<0.05) by dentist’s gender, practice type, region, practice busyness, insurance coverage, hours worked/week, and location type. Conclusions Network dentists use a broad range of materials for single-unit crowns for anterior and posterior teeth, adopting newer materials into their practices as they become available. Material choices are significantly associated with dentist’s and practice’s characteristics. Clinical Significance Decisions for crown material may be influenced by factors unrelated to tooth and patient variables. Dentists should be cognizant of this when developing an evidence-based approach to selecting crown material. PMID:27693778

Adhesive dental materials

International Nuclear Information System (INIS)

Unlu, N.

2005-01-01

Two main classes of material are involved, the glass-ionomer cements and the composite resins. This investigation describes the way they are bonded to the tooth and highlights their differences. Glass ionomers develop a zone of interaction with the tooth as they age which ultimately gives an extremely strong bond, and results in excellent retention rates. By contrast, bonding of composite resins is more complicated and possibly less effective, though these materials have better wear resistance and better aesthetics than glass ionomers. Assessment of bond durability is difficult. This is because a dental restorative can fail by a number of mechanisms apart from de bonding: for example, through wear or fracture

An evaluation of dental operative simulation materials.

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He, Li-Hong; Foster Page, Lyndie; Purton, David

2012-01-01

The study was to evaluate the performance of different materials used in dental operative simulation and compare them with those of natural teeth. Three typical phantom teeth materials were compared with extracted permanent teeth by a nanoindentation system and evaluated by students and registered dentists on the drilling sensation of the materials. Moreover, the tool life (machinability) of new cylindrical diamond burs on cutting the sample materials was tested and the burs were observed. Although student and dentist evaluations were scattered and inconclusive, it was found that elastic modulus (E) and hardness (H) were not the main factors in determining the drilling sensation of the materials. The sensation of drilling is a reflection of cutting force and power consumption.An ideal material for dental simulation should be able to generate similar drilling resistance to that of natural tooth, which is the machinability of the material.

Influence of metal dental materials on MR imaging

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Tsuchihashi, Toshio; Chiba, Michiko; Yoshizawa, Satoshi; Sasaki, Sadayuki; Maki, Toshio; Kitagawa, Matsuo; Suzuki, Takeshi [Nippon Medical School, Tokyo (Japan). Main Hospital; Nakata, Minoru; Fujita, Isao

1998-11-01

Differences in magnetic susceptibility produce artifacts and signal loss in magnetic resonance imaging (MRI). This study was undertaken to compare the degree of artifacts on MRI caused by metallic dental materials. The influence on MRI of six types of dental alloys, a dental implant, orthodontic appliance, and magnetic attachment was investigated. Among the dental metals, nickel-chromium alloy and cobalt-chromium alloy, which have ferromagnetism, caused significant metal artifacts. Gold-platinum alloy, gold-silver-palladium alloy, silver alloy, and amalgam alloy produced slight metal artifacts. The orthodontic appliance mainly consisted of iron, and the keeper for its magnetic attachment was made of stainless steel. For these reasons, marked metal artifacts and signal loss could be seen in both of them owing to their ferromagnetism. These results suggest that orthodontic appliances and magnetic attachments impair evaluation of the GRE and EPI techniques. It is therefore preferable to use predominantly diamagnetic or paramagnetic dental materials for MRI of the head and neck. Removable keepers should be used more widely to prevent metal artifacts and enhance safety on MRI. (author)

Influence of metal dental materials on MR imaging

International Nuclear Information System (INIS)

Tsuchihashi, Toshio; Chiba, Michiko; Yoshizawa, Satoshi; Sasaki, Sadayuki; Maki, Toshio; Kitagawa, Matsuo; Suzuki, Takeshi; Nakata, Minoru; Fujita, Isao

1998-01-01

Differences in magnetic susceptibility produce artifacts and signal loss in magnetic resonance imaging (MRI). This study was undertaken to compare the degree of artifacts on MRI caused by metallic dental materials. The influence on MRI of six types of dental alloys, a dental implant, orthodontic appliance, and magnetic attachment was investigated. Among the dental metals, nickel-chromium alloy and cobalt-chromium alloy, which have ferromagnetism, caused significant metal artifacts. Gold-platinum alloy, gold-silver-palladium alloy, silver alloy, and amalgam alloy produced slight metal artifacts. The orthodontic appliance mainly consisted of iron, and the keeper for its magnetic attachment was made of stainless steel. For these reasons, marked metal artifacts and signal loss could be seen in both of them owing to their ferromagnetism. These results suggest that orthodontic appliances and magnetic attachments impair evaluation of the GRE and EPI techniques. It is therefore preferable to use predominantly diamagnetic or paramagnetic dental materials for MRI of the head and neck. Removable keepers should be used more widely to prevent metal artifacts and enhance safety on MRI. (author)

Optical investigations of various polymeric materials used in dental technology

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Negrutiu, Meda Lavinia; Sinescu, Cosmin; Topala, Florin Ionel; Ionita, Ciprian; Goguta, Luciana; Marcauteanu, Corina; Rominu, Mihai; Podoleanu, Adrian Gh.

2011-10-01

Dental prosthetic restorations have to satisfy high stress as well as aesthetic requirements. In order to avoid deficiencies of dental prostheses, several alternative systems and procedures were imagined, directly related to the material used and also to the manufacturing technology. Increasing the biomechanical comportment of polymeric materials implies fiber reinforcing. The different fibers reinforcing products made very difficult the evaluation of their performances and biomechanical properties analysis. There are several known methods which are used to assess the quality of dental prostheses, but most are invasive. These lead to the destruction of the samples and often no conclusion could be drawn in the investigated areas of interest. Using a time domain en-face OCT system, we have recently demonstrated real time thorough evaluation of quality of various dental treatments. The aim of this study was to assess the quality of various polymeric materials used in dental technology and to validate the en face OCT imagistic evaluation of polymeric dental prostheses by using scanning electron microscopy (SEM) and microcomputer tomography (μCT). SEM investigations evidenced the nonlinear aspect of the interface between the polymeric material and the fiber reinforcement and materials defects in some samples. The results obtained by microCT revealed also some defects inside the polymeric materials and at the interfaces with the fiber reinforcement. The advantages of the OCT method consist in non-invasiveness and high resolution. In addition, en face OCT investigations permit visualization of the more complex stratified structure at the interface between the polymeric material and the fiber reinforcement.

Recent Advances in Material and Geometrical Modelling in Dental Applications

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Waleed M. S. Al Qahtani

2018-06-01

Full Text Available This article touched, in brief, the recent advances in dental materials and geometric modelling in dental applications. Most common categories of dental materials as metallic alloys, composites, ceramics and nanomaterials were briefly demonstrated. Nanotechnology improved the quality of dental biomaterials. This new technology improves many existing materials properties, also, to introduce new materials with superior properties that covered a wide range of applications in dentistry. Geometric modelling was discussed as a concept and examples within this article. The geometric modelling with engineering Computer-Aided-Design (CAD system(s is highly satisfactory for further analysis or Computer-Aided-Manufacturing (CAM processes. The geometric modelling extracted from Computed-Tomography (CT images (or its similar techniques for the sake of CAM also reached a sufficient level of accuracy, while, obtaining efficient solid modelling without huge efforts on body surfaces, faces, and gaps healing is still doubtable. This article is merely a compilation of knowledge learned from lectures, workshops, books, and journal articles, articles from the internet, dental forum, and scientific groups' discussions.

A useful and non-invasive microanalysis method for dental restoration materials

International Nuclear Information System (INIS)

Hosoki, M.; Satsuma, T.; Nishigawa, K.; Takeuchi, H.; Asaoka, K.

2012-01-01

Highlights: ► This method for the microanalysis of dental alloys is beneficial for patients with allergies to dental materials. ► This metal sample is easy to mail it for inspection at specialist institutes. ► This method can be also be used in general dental clinics. - Abstract: The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 μg. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

A useful and non-invasive microanalysis method for dental restoration materials

Energy Technology Data Exchange (ETDEWEB)

Hosoki, M., E-mail: hosoki@tokushima-u.ac.jp [Department of Fixed Prosthodontics, Institute of Health Biosciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan); Satsuma, T.; Nishigawa, K.; Takeuchi, H. [General Dentistry, Tokushima University Hospital, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan); Asaoka, K. [Department of Biomaterials and Bioengineering, Institute of Health Biosciences, University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8504 (Japan)

2012-12-01

Highlights: Black-Right-Pointing-Pointer This method for the microanalysis of dental alloys is beneficial for patients with allergies to dental materials. Black-Right-Pointing-Pointer This metal sample is easy to mail it for inspection at specialist institutes. Black-Right-Pointing-Pointer This method can be also be used in general dental clinics. - Abstract: The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 {mu}g. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

Various Effects of Sandblasting of Dental Restorative Materials.

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Goro Nishigawa

Full Text Available Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials.We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC group and non-ultrasonic cleaning (NUSC group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength.For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group.Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials.

Evaluation of Survival Time of Tooth Color Dental Materials in Primary Anterior Teeth

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Behjat-Al-Molook Ajami

2013-01-01

Full Text Available Introduction: In restorative dentistry, selecting the proper material is an important factor for clinical success. The objective of this study was clinical evaluation of survival time of three tooth color materials in primary anterior teeth. Methods: In this interventional clinical trial study, 94 deciduous anterior teeth (36 teeth in boys, 58 teeth in girls belonging to 3-5 year old children in Pediatric Department of Mashhad Faculty of Dentistry, Iran were selected. Selective dental materials included compoglass, glass-ionomer Fuji II LC, and composite resin. The data were analyzed with Kaplan–Meyer and Log rank test. Results: compoglass had the highest survival time in comparison with composite and glass-ionomer. Nine months retention rate for teeth restored with compoglass, composite resin and glass-ionomer were estimated: 95%, 21%, and 12.5%, respectively. Conclusion: Compoglass can be a suitable material for anterior primary teeth restoration

Evaluation of Survival Time of Tooth Color Dental Materials in Primary Anterior Teeth

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Taraneh Movahhed

2012-09-01

Full Text Available Introduction: In restorative dentistry, selecting the proper material is an important factor for clinical success. The objective of this study was clinical evaluation of survival time of three tooth color materials in primary anterior teeth. Methods: In this interventional clinical trial study, 94 deciduous anterior teeth (36 teeth in boys, 58 teeth in girls belonging to 3-5 year old children in Pediatric Department of Mashhad Faculty of Dentistry, Iran were selected. Selective dental materials included compoglass, glass-ionomer Fuji II LC, and composite resin. The data were analyzed with Kaplan–Meyer and Log rank test. Results: compoglass had the highest survival time in comparison with composite and glass-ionomer. Nine months retention rate for teeth restored with compoglass, composite resin and glass-ionomer were estimated: 95%, 21%, and 12.5%, respectively. Conclusion: Compoglass can be a suitable material for anterior primary teeth restoration.

A useful and non-invasive microanalysis method for dental restoration materials

Science.gov (United States)

Hosoki, M.; Satsuma, T.; Nishigawa, K.; Takeuchi, H.; Asaoka, K.

2012-12-01

The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

Perceived Visual Deterioration among a Selected Group of Dental ...

African Journals Online (AJOL)

To assess the perceived visual deterioration and the determinants among selected dental surgeons in Nigeria. A cross-sectional survey of Resident doctors attending the Revision course of Faculty of Dental Surgery of the National Postgraduate Medical College of Nigeria in Lagos University Teaching Hospital, Lagos, ...

The relative patient costs and availability of dental services, materials and equipment in public oral care facilities in Tanzania.

Science.gov (United States)

Nyamuryekung'e, Kasusu K; Lahti, Satu M; Tuominen, Risto J

2015-07-01

Patient charges and availability of dental services influence utilization of dental services. There is little available information on the cost of dental services and availability of materials and equipment in public dental facilities in Africa. This study aimed to determine the relative cost and availability of dental services, materials and equipment in public oral care facilities in Tanzania. The local factors affecting availability were also studied. A survey of all district and regional dental clinics in selected regions was conducted in 2014. A total of 28/30 facilities participated in the study. A structured interview was undertaken amongst practitioners and clinic managers within the facilities. Daily resources for consumption (DRC) were used for estimation of patients' relative cost. DRC are the quantified average financial resources required for an adult Tanzanian's overall consumption per day. Tooth extractions were found to cost four times the DRC whereas restorations were 9-10 times the DRC. Studied facilities provided tooth extractions (100%), scaling (86%), fillings (79%), root canal treatment (46%) and fabrication of removable partial dentures (32%). The ratio of tooth fillings to extractions in the facilities was 1:16. Less than 50% of the facilities had any of the investigated dental materials consistently available throughout the year, and just three facilities had all the investigated equipment functional and in use. Dental materials and equipment availability, skills of the practitioners and the cost of services all play major roles in provision and utilization of comprehensive oral care. These factors are likely to be interlinked and should be taken into consideration when studying any of the factors individually.

Nano materials for Medical and Dental Applications

International Nuclear Information System (INIS)

Yub Kwon, T.; Oh, D.S.; Narayanan, R.

2015-01-01

Welcome to this special issue. Nano science and nano technology concepts are applicable across all fields of science and a more widespread application of nano materials and nano technologies is imminent or already occurring in many areas, including health care. Today is scientists take those cutting-edge technologies and concepts and apply them to medicine and dentistry. They are finding a wide variety of ways to make medical and dental materials at the nano scale to take advantage of their enhanced physical and biological properties.The purpose of this special issue is to publish high-quality research papers as well as review articles addressing recent advances in the field of nano materials for medical and dental applications. A particular interest is given to papers exploring or discussing nano materials and nano technologies related to delivery system, bonding substitutes, and surface modification techniques applicable in these areas. For this special issue, several investigators were invited to contribute original research findings that can stimulate continuing efforts to understand the cutting-edge applications of nano materials in medicine and dentistry.

Amino acid derivative-mediated detoxification and functionalization of dual cure dental restorative material for dental pulp cell mineralization.

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Minamikawa, Hajime; Yamada, Masahiro; Iwasa, Fuminori; Ueno, Takeshi; Deyama, Yoshiaki; Suzuki, Kuniaki; Yawaka, Yasutaka; Ogawa, Takahiro

2010-10-01

Current dental restorative materials are only used to fill the defect of hard tissues, such as dentin and enamel, because of their cytotoxicity. Therefore, exposed dental pulp tissues in deep cavities must be first covered by a pulp capping material like calcium hydroxide to form a layer of mineralized tissue. However, this tissue mineralization is based on pathological reaction and triggers long-lasting inflammation, often causing clinical problems. This study tested the ability of N-acetyl cysteine (NAC), amino acid derivative, to reduce cytotoxicity and induce mineralized tissue conductivity in resin-modified glass ionomer (RMGI), a widely used dental restorative material having dual cure mechanism. Rat dental pulp cells were cultured on untreated or NAC-supplemented RMGI. NAC supplementation substantially increased the percentage of viable cells from 46.7 to 73.3% after 24-h incubation. Cell attachment, spreading, proliferative activity, and odontoblast-related gene and protein expressions increased significantly on NAC-supplemented RMGI. The mineralization capability of cells, which was nearly suppressed on untreated RMGI, was induced on NAC-supplemented RMGI. These improved behaviors and functions of dental pulp cells on NAC-supplemented RMGI were associated with a considerable reduction in the production of intracellular reactive oxygen species and with the increased level of intracellular glutathione reserves. These results demonstrated that NAC could detoxify and functionalize RMGIs via two different mechanisms involving in situ material detoxification and antioxidant cell protection. We believe that this study provides a new approach for developing dental restorative materials that enables mineralized tissue regeneration.

Wear measurement of dental tissues and materials in clinical studies: A systematic review.

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Wulfman, C; Koenig, V; Mainjot, A K

2018-06-01

This study aims to systematically review the different methods used for wear measurement of dental tissues and materials in clinical studies, their relevance and reliability in terms of accuracy and precision, and the performance of the different steps of the workflow taken independently. An exhaustive search of clinical studies related to wear of dental tissues and materials reporting a quantitative measurement method was conducted. MedLine, Embase, Scopus, Cochrane Library and Web of Science databases were used. Prospective studies, pilot studies and case series (>10 patients), as long as they contained a description of wear measurement methodology. Only studies published after 1995 were considered. After duplicates' removal, 495 studies were identified, and 41 remained for quantitative analysis. Thirty-four described wear-measurement protocols, using digital profilometry and superimposition, whereas 7 used alternative protocols. A specific form was designed to analyze the risk of bias. The methods were described in terms of material analyzed; study design; device used for surface acquisition; matching software details and settings; type of analysis (vertical height-loss measurement vs volume loss measurement); type of area investigated (entire occlusal area or selective areas); and results. There is a need of standardization of clinical wear measurement. Current methods exhibit accuracy, which is not sufficient to monitor wear of restorative materials and tooth tissues. Their performance could be improved, notably limiting the use of replicas, using standardized calibration procedures and positive controls, optimizing the settings of scanners and matching softwares, and taking into account unusable data. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Matching the optical properties of direct esthetic dental restorative materials to those of human enamel and dentin

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Ragain, James Carlton, Jr.

One of the goals of the restorative dentist is to restore the appearance of the natural dentition. Clinical matching of teeth and restorative materials are seldom accurate and shade selection techniques are subjective. The first specific aim of this research was to characterize the optical absorption and scattering that occurs within enamel, dentin, and composite resin and compomer restorative materials and to relate those phenomena to translucency and color. The second aim was to evaluate small color differences among composite restorative materials which would be detectable by humans. The last aim was to lay the foundation for developing an improved model of specifying layers of dental restorative materials in order to match the translucency and color to those of human enamel. The Kubelka-Munk theory was validated for enamel, dentin, and the restorative materials. These tissues and materials were then characterized in terms of their color parameters. Tooth cores were also characterized in terms of color space parameters. Human subjects were evaluated for their abilities to discriminate small color differences in the dental composite resin materials. The following conclusions were derived from this study: (1) Kubelka-Munk theory accurately predicts the diffuse reflectance spectra of enamel, dentin, and the direct esthetic dental restorative materials studied. (2) Scattering and absorption coefficients of the dental tissues and esthetic restorative materials can be directly calculated from diffuse reflectance measurements of a uniformly thick slab of tissue/material using black and white backings and the appropriate refractive index. (3) For tooth cores, there is a positive correlation between L* and b* and a negative correlation between L* and a*. (4) The range of translucency parameters for the restorative materials studied does not match those of enamel and dentin. (5) None of the shades of the dental composite resin restorative materials studied fit into the

Effects of hydrogen peroxide bleaching strip gels on dental restorative materials in vitro: surface microhardness and surface morphology.

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Duschner, Heinz; Götz, Hermann; White, Donald J; Kozak, Kathleen M; Zoladz, James R

2004-01-01

This study examined the effects of peroxide tooth bleaching, including Crest Whitestrips hydrogen peroxide gel treatments, on the surface hardness and morphology of common dental restorative treatments. American Dental Association (ADA) recommended dental restorative materials, including amalgam, dental gold, porcelain, glass ionomer, and composites, were prepared according to manufacturers' instructions. A cycling treatment methodology was employed which alternated ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching gels, which utilize hydrogen peroxide as the in situ bleaching source, and several commercial carbamide peroxide bleaching gels. Control treatments included placebo gels and an untreated group. Crest Whitestrips bleaching included treatment exposures simulating recommended clinical exposures (14 hours), along with excess bleaching simulating exposure to five times suggested Crest Whitestrips use. At the conclusion of treatments, surface microhardness measures and surface morphological assessments with standard and variable pressure (VP-) SEMs were conducted to assess the effects of bleaching exposure on the surface morphology and structural integrity of the restoratives. Surface microhardness and SEM measures revealed no significant deleterious effects on the restoration surfaces from Whitestrips gels. These results confirm that tooth bleaching from the selected commercial hydrogen peroxide or carbamide peroxide bleaching systems does not produce changes in surface morphology or microhardness of common dental restorative materials. These results support the clinical safety of the selected commercial bleaching systems to the oral environment, matching results obtained from long-term use of these ingredients applied in dental offices and available in commercial formulations.

DEGREE OF AWARENESS OF SOFT RELINING MATERIALS BY DENTAL TECHNICIANS

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Ilian Hristov

2017-10-01

Full Text Available The aim of the current investigation is to analyze the dental-technicians’ awareness of the soft relining materials, their characteristics, advantages, shortcomings and methods for relining. Materials and methods: For the purpose of this investigation a standard questionnaire has been presented. A direct survey method, documentary and statistical method, as well as graphical methods, including tables, charts, graphics and figures, were used. Data were analysed with the help of IBM SPSS Statistics (ver. 19. Results: One hundred and eight dental technicians were included in the survey, evenly distributed by gender. Removable and fixed prosthodontics is the most commonly mentioned spheres of dental activities. Almost all included in the investigation point out the laboratory relining method as the most frequently used. Acrylic and silicone SRM are the most used groups of relining materials. Change of colour and hardness are the most frequently noticed shortcomings of these materials. The majority of the dental technicians declare that they have never done replacement of SRM or the relining has lasted more than a year. Discussion: The correlation between the age and the years of labour service among the participants is quite obvious. Most of them start working soon after their graduation. Removable prosthodontics is among the priorities for the majority of the labs. Conclusion: Although their unambiguous advantages, the soft relining materials have lots of shortcomings as well. The major problems are connected with their change of colour and hardness. Nevertheless, the dental technicians find them useful and reliable in overcoming specific prosthetic problems.

Advances in Dental Materials through Nanotechnology: Facts, Perspectives and Toxicological Aspects.

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Padovani, Gislaine C; Feitosa, Victor P; Sauro, Salvatore; Tay, Franklin R; Durán, Gabriela; Paula, Amauri J; Durán, Nelson

2015-11-01

Nanotechnology is currently driving the dental materials industry to substantial growth, thus reflecting on improvements in materials available for oral prevention and treatment. The present review discusses new developments in nanotechnology applied to dentistry, focusing on the use of nanomaterials for improving the quality of oral care, the perspectives of research in this arena, and discussions on safety concerns regarding the use of dental nanomaterials. Details are provided on the cutting-edge properties (morphological, antibacterial, mechanical, fluorescence, antitumoral, and remineralization and regeneration potential) of polymeric, metallic and inorganic nano-based materials, as well as their use as nanocluster fillers, in nanocomposites, mouthwashes, medicines, and biomimetic dental materials. Nanotoxicological aspects, clinical applications, and perspectives for these nanomaterials are also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

The presence of antimony in various dental filling materials

International Nuclear Information System (INIS)

Molokhia, Anat; Combe, E.C.; Lilley, J.D.

1985-01-01

Antimony was determined in a number of non-metallic dental materials currently used for tooth restoration. The method applied was instrumental neutron activation analysis. The concentration of antimony in some of the brands tested was found to be as high as 900 fold that in the normal hard dental tissues. (author)

On stress/strain shielding and the material stiffness paradigm for dental implants.

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Korabi, Raoof; Shemtov-Yona, Keren; Rittel, Daniel

2017-10-01

Stress shielding considerations suggest that the dental implant material's compliance should be matched to that of the host bone. However, this belief has not been confirmed from a general perspective, either clinically or numerically. To characterize the influence of the implant stiffness on its functionality using the failure envelope concept that examines all possible combinations of mechanical load and application angle for selected stress, strain and displacement-based bone failure criteria. Those criteria represent bone yielding, remodeling, and implant primary stability, respectively MATERIALS AND METHODS: We performed numerical simulations to generate failure envelopes for all possible loading configurations of dental implants, with stiffness ranging from very low (polymer) to extremely high, through that of bone, titanium, and ceramics. Irrespective of the failure criterion, stiffer implants allow for improved implant functionality. The latter reduces with increasing compliance, while the trabecular bone experiences higher strains, albeit of an overall small level. Micromotions remain quite small irrespective of the implant's stiffness. The current paradigm favoring reduced implant material's stiffness out of concern for stress or strain shielding, or even excessive micromotions, is not supported by the present calculations, that point exactly to the opposite. © 2017 Wiley Periodicals, Inc.

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

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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.

Beyond food: The multiple pathways for inclusion of materials into ancient dental calculus.

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Radini, Anita; Nikita, Efthymia; Buckley, Stephen; Copeland, Les; Hardy, Karen

2017-01-01

Dental calculus (mineralized dental plaque) was first recognised as a potentially useful archaeological deposit in the 1970s, though interest in human dental calculus as a resource material has increased sharply in the past few years. The majority of recent research has focused on the retrieval of plant microfossils embedded in its matrix and interpretation of these finds as largely the result of deliberate consumption of plant-derived food. However, while most of the material described in published works does represent food, dental calculus is in fact a "depositional environment" as material can enter the mouth from a range of sources. In this respect, it therefore represents an archaeological deposit that can also contain extensive non-dietary debris. This can comprise a wide variety of cultural and environmental material which reaches the mouth and can become embedded in dental calculus through alternative pathways. Here, we explore the human behaviors and activities besides eating that can generate a flux of particles into the human mouth, the broad range of additional cultural and environmental information that can be obtained through the analysis and contextualisation of this material, and the implications of the additional pathways by which material can become embedded in dental calculus. © 2017 American Association of Physical Anthropologists.

Effect of dental restorative materials on total antioxidant capacity and calcium concentration of unstimulated saliva.

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Ramezani, Gholam H; Moghadam, Mona-Momeni; Saghiri, Mohammad-Ali; Garcia-Godoy, Franklin; Asatourian, Armen; Aminsobhani, Mohsen; Scarbecz, Mark; Sheibani, Nader

2017-01-01

To evaluate the effect of dental amalgam and composite restorations on total antioxidant capacity (TAC) and calcium (Ca) ion concentration of unstimulated saliva. Forty-eight children aged 6-10 years selected and divided into three groups of sixteen (8 males, 8 females). In group A and B, samples consisted of two class II dental composite or amalgam restorations, while in group C samples were caries-free (control group). Unstimulated saliva from all samples was collected and TAC was measured by spectrophotometry using an adaptation of 2, 2'-azino-di-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assay. The Ca ion level was estimated by an auto- analyzer. Data were analyzed with one- and two-way ANOVA test, at a p difference between groups ( p differences within and between groups ( p Gender is an effective factor in changes induced in oral cavity as females showed more emphatic reaction to dental filling materials than males. Patients who have dental restorations, especially dental composites, should pay more attention to their dental hygiene, because dental restorations can increase oxidative stress and decrease Ca ion level in saliva, which might jeopardize remineralization process of tooth structures after demineralization. Key words: Amalgam, caries, composite, saliva, total antioxidant capacity.

Titanium Nitride and Nitrogen Ion Implanted Coated Dental Materials

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David W. Berzins

2012-07-01

Full Text Available Titanium nitride and/or nitrogen ion implanted coated dental materials have been investigated since the mid-1980s and considered in various applications in dentistry such as implants, abutments, orthodontic wires, endodontic files, periodontal/oral hygiene instruments, and casting alloys for fixed restorations. Multiple methodologies have been employed to create the coatings, but detailed structural analysis of the coatings is generally lacking in the dental literature. Depending on application, the purpose of the coating is to provide increased surface hardness, abrasion/wear resistance, esthetics, and corrosion resistance, lower friction, as well as greater beneficial interaction with adjacent biological and material substrates. While many studies have reported on the achievement of these properties, a consensus is not always clear. Additionally, few studies have been conducted to assess the efficacy of the coatings in a clinical setting. Overall, titanium nitride and/or nitrogen ion implanted coated dental materials potentially offer advantages over uncoated counterparts, but more investigation is needed to document the structure of the coatings and their clinical effectiveness.

The radiological installation in dental office: selection and performance

International Nuclear Information System (INIS)

Cirre, Christian

2010-01-01

This thesis for a PhD in dental surgery aimed at identifying and analysing different ways to optimise radiographs. In a first part, the author presents the characteristics of X rays, and dosimetric values used in dental offices. He describes the interaction of X rays with living cells by recalling the discovery of biological effects and the emergence of radiation protection, and by discussing the consequences for the patient as well as for the practician. In the next part, the author comments technological advances of devices, and means available to practicians to improve their performance. He presents X ray tubes, discusses factors which influence ray production, and selection criteria, indicates additional devices (beam application tubes, filtration, collimation), discusses the selection of the receiver (types of receivers used in intra-oral radiology, digital or silver film-based sensors), and describes the picture-taking process (radiological techniques, use of angulators and lead shielding). He finally discusses how to optimise intra-oral dental imagery through good practices which comprise optimisation, selection of apparatuses and devices, performance of the radiological act with a patient sitting in the armchair, and maintenance of a good image quality [fr

Artifacts by dental materials on magnetic resonance imaging

International Nuclear Information System (INIS)

Hong, Hyun Sook; Choi, Deuk Lin; Kim, Ki Jung; Suh, Won Hyuck

1992-01-01

Magnetic resonance imaging (MRI) has proved to be a valuable method for evaluation of the head and neck. Unfortunately, metallic devices associated with certain dental fillings and appliances often cause variable artifacts that can obscure normal or pathologic conditions on MR and computed tomography. In this work, we assessed the MR appearance of dental prosthetic materials in vitro and in vivo including precious alloys, nonprecions alloys, resin, amalgam and titanium alloy. For in vivo studies, these materials were placed in healthy volunteer's mouths and then images were assessed. Analysis of the appearance of shape and extent of artifact, and observed influence of these artifacts on the image interpretation at 0.2 Tesla permanent type MR scanner were valuated. Material used as temporary or permanent filling of crowns such as amalgam, precious alloy and, microfilled resin did not cause artifact on the image. The size of the artifact produced by the nonprecious alloys was influenced by the ferromagnetism of the object and the volume prosthesis, and was related to the scanning sequence. Nonprecious alloys produced minimal local signal distortion, where precious alloys, and dental resin had no effect on the MR images in vivo. These results were mainly from a low field strength MR scanner used in this study

SU-E-T-89: Characterization of Dental Restoration Material for Cs-137 Radiation Dosimetry.

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Ratliff, S; Gustafson, B; Barry, K

2012-06-01

The purpose of this work is to characterize the radiation-induced thermoluminescence properties of a dental restoration material and to see if the material might be feasible for use in retrospective radiation dosimetry. Retrospective, or accidental, dosimetry is the study of using nearby materials to measure radiation received by individuals. In this project we obtained samples of Ivoclar Vivadent e.max CAD material, a glass-ceramic used for making dental restorations such as full or partial crowns. The samples were machined into square chips .32 cm × .32 cm × .089 cm and annealed in the same furnace used by the dentist. The samples were exposed to a Cs-137 source using a PMMA source holder and then read in a Harshaw 3500 TLD reader. The samples were read without nitrogen gas flux using heating rates of 5 degrees C/s or 10 degrees C/s up to a maximum temperature of 400 degrees Celsius. The glow curves were analyzed using Systat PeakFIT peak-fitting software and Microsoft Excel spreadsheets. The authors gratefully thank Dr. Aaron Imdieke and the staff of River City Dental, St. Cloud, MN for the dental restoration materials and the use of their dental furnace. A sample subjected to a radiation exposure of .04 C/kg exhibits a glow curve with a prominent peak at approximately 140 degrees Celsius, which is well-modeled by the first order glow curve deconvolution formula developed by Kitis, Gomez-Ros, and Tuyn. The activation energy corresponding to this peak is approximately 1 eV. The thermoluminescent signal fades with time after exposure. Ivoclar Vivadent e.max CAD dental restoration material has the potential to be used as a material for retrospective Cs-137 radiation dosimetry. Future work could look at its thermoluminescent dosimetry properties in more detail and also at other dental restoration materials. The authors would like to thank Dr. Aaron Imdieke and the staff of River City Dental, St. Cloud, MN, for the donation of scrap dental restoration materials and

Synthetic Light-Curable Polymeric Materials Provide a Supportive Niche for Dental Pulp Stem Cells.

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Vining, Kyle H; Scherba, Jacob C; Bever, Alaina M; Alexander, Morgan R; Celiz, Adam D; Mooney, David J

2018-01-01

Dental disease annually affects billions of patients, and while regenerative dentistry aims to heal dental tissue after injury, existing polymeric restorative materials, or fillings, do not directly participate in the healing process in a bioinstructive manner. There is a need for restorative materials that can support native functions of dental pulp stem cells (DPSCs), which are capable of regenerating dentin. A polymer microarray formed from commercially available monomers to rapidly identify materials that support DPSC adhesion is used. Based on these findings, thiol-ene chemistry is employed to achieve rapid light-curing and minimize residual monomer of the lead materials. Several triacrylate bulk polymers support DPSC adhesion, proliferation, and differentiation in vitro, and exhibit stiffness and tensile strength similar to existing dental materials. Conversely, materials composed of a trimethacrylate monomer or bisphenol A glycidyl methacrylate, which is a monomer standard in dental materials, do not support stem cell adhesion and negatively impact matrix and signaling pathways. Furthermore, thiol-ene polymerized triacrylates are used as permanent filling materials at the dentin-pulp interface in direct contact with irreversibly injured pulp tissue. These novel triacrylate-based biomaterials have potential to enable novel regenerative dental therapies in the clinic by both restoring teeth and providing a supportive niche for DPSCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interpenetrating network ceramic-resin composite dental restorative materials.

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Swain, M V; Coldea, A; Bilkhair, A; Guess, P C

2016-01-01

This paper investigates the structure and some properties of resin infiltrated ceramic network structure materials suitable for CAD/CAM dental restorative applications. Initially the basis of interpenetrating network materials is defined along with placing them into a materials science perspective. This involves identifying potential advantages of such structures beyond that of the individual materials or simple mixing of the components. Observations from a number of recently published papers on this class of materials are summarized. These include the strength, fracture toughness, hardness and damage tolerance, namely to pointed and blunt (spherical) indentation as well as to burr adjustment. In addition a summary of recent results of crowns subjected to simulated clinical conditions using a chewing simulator are presented. These results are rationalized on the basis of existing theoretical considerations. The currently available ceramic-resin IPN material for clinical application is softer, exhibits comparable strength and fracture toughness but with substantial R-curve behavior, has lower E modulus and is more damage tolerant than existing glass-ceramic materials. Chewing simulation observations with crowns of this material indicate that it appears to be more resistant to sliding/impact induced cracking although its overall contact induced breakage load is modest. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Legal analysis of information displayed on dental material packages: An exploratory research

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Bhumika Rathore

2016-01-01

Full Text Available Introduction: Some of the dental materials possess occupational hazards, preprocedural errors, and patient allergies as suggested by evidence. With due consideration to safety of the patients and dental professionals, it is essential that the trade of these materials is in conformity with the law. Aim: To perform the legal analysis of the information displayed on the packaging of dental materials. Materials and Methods: The Bureau of Indian Standards sets guidelines for packaging and marketing of dental products in India. An exploratory cross-sectional study was performed using various search engines and websites to access the laws and regulations existing pertaining to dental materials packaging. Based on the data obtained, a unique packaging standardization checklist was developed. Dental laboratory and impression plasters, alginates, and endodontic instruments were surveyed for all the available brands. This study considered 16 brands of plasters and alginates and 42 brands of endodontic instruments for legal analysis. Legal analysis was performed using the direct observation checklist. Descriptive statistics were obtained using SPSS version 19. Results: The guidelines set by the Bureau of Indian Standards do exist but are not updated and stand as oblivious guards for marketing standards. Overall compliance to the guidelines was reported to be 18.5% by brands of alginates, 4.1% by plaster of Paris, and 11.11% by endodontic instruments. Wave One™ File reported maximum adherence with the guidelines as 66.7%. Conclusion: This study found lower rate of adherence to the guidelines, thus indicating insufficient information being disclosed to the consumers.

Dental ceramics: a review of new materials and processing methods.

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Silva, Lucas Hian da; Lima, Erick de; Miranda, Ranulfo Benedito de Paula; Favero, Stéphanie Soares; Lohbauer, Ulrich; Cesar, Paulo Francisco

2017-08-28

The evolution of computerized systems for the production of dental restorations associated to the development of novel microstructures for ceramic materials has caused an important change in the clinical workflow for dentists and technicians, as well as in the treatment options offered to patients. New microstructures have also been developed by the industry in order to offer ceramic and composite materials with optimized properties, i.e., good mechanical properties, appropriate wear behavior and acceptable aesthetic characteristics. The objective of this literature review is to discuss the main advantages and disadvantages of the new ceramic systems and processing methods. The manuscript is divided in five parts: I) monolithic zirconia restorations; II) multilayered dental prostheses; III) new glass-ceramics; IV) polymer infiltrated ceramics; and V) novel processing technologies. Dental ceramics and processing technologies have evolved significantly in the past ten years, with most of the evolution being related to new microstructures and CAD-CAM methods. In addition, a trend towards the use of monolithic restorations has changed the way clinicians produce all-ceramic dental prostheses, since the more aesthetic multilayered restorations unfortunately are more prone to chipping or delamination. Composite materials processed via CAD-CAM have become an interesting option, as they have intermediate properties between ceramics and polymers and are more easily milled and polished.

A concise overview of dental implantology

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Olanrewaju Abdurrazaq Taiwo

2015-01-01

Full Text Available Background: The emergence of osseointegrated dental implants has resulted in several applications in diverse clinical settings. Hence, has contributed to the suitable replacement of missing teeth and the realization of an optimal facial appearance. This paper describes the benefits, applications, contraindications, and complications of dental implants in contemporary dental practice. Materials and Methods: An electronic search was undertaken in PUBMED without time restriction for appropriate English papers on dental implants based on a series of keywords in different combinations. Results: Fifty-eight acceptable, relevant articles were selected for review. The review identified the various components of dental implants, classification, and brands. It also looked at osseointegration and factors promoting and inimical to it. It also explored primary and secondary stability; and patients' selection for a dental implant. Complications of dental implants were also highlighted. Conclusion: With over 95% success rate, dental implants remain the gold standard for achieving aesthetic and functional oral rehabilitation.

Special cluster issue on tribocorrosion of dental materials

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Mathew, Mathew T.; Stack, Margaret M.

2013-10-01

Tribocorrosion affects all walks of life from oil and gas conversion to biomedical materials. Wear can interact with corrosion to enhance it or impede it; conversely, corrosion can enhance or impede wear. The understanding of the interactions between physical and chemical phenomena has been greatly assisted by electrochemical and microscopic techniques. In dentistry, it is well recognized that erosion due to dissolution (a term physicists use to denote wear) of enamel can result in tooth decay; however, the effects of the oral environment, i.e. pH levels, electrochemical potential and any interactions due to the forces involved in chewing are not well understood. This special cluster issue includes investigations on the fundamentals of wear-corrosion interactions involved in simulated oral environments, including candidate dental implant and veneer materials. The issue commences with a fundamental study of titanium implants and this is followed by an analysis of the behaviour of commonly used temporomandibular devices in a synovial fluid-like environment. The analysis of tribocorrosion mechanisms of Ti6Al4V biomedical alloys in artificial saliva with different pHs is addressed and is followed by a paper on fretting wear, on hydroxyapatite-titanium composites in simulated body fluid, supplemented with protein (bovine serum albumin). The effects of acid treatments on tooth enamel, and as a surface engineering technique for dental implants, are investigated in two further contributions. An analysis of the physiological parameters of intraoral wear is addressed; this is followed by a study of candidate dental materials in common beverages such as tea and coffee with varying acidity and viscosity and the use of wear maps to identify the safety zones for prediction of material degradation in such conditions. Hence, the special cluster issue consists of a range of tribocorrosion contributions involving many aspects of dental tribocorrosion, from analysis of physiological

The Mechanical Behaviors of Various Dental Implant Materials under Fatigue

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Fatma Bayata

2018-01-01

Full Text Available The selection of materials has a considerable role on long-term stability of implants. The materials having high resistance to fatigue are required for dental implant applications since these implants are subjected to cyclic loads during chewing. This study evaluates the performance of different types of materials (AISI 316L stainless steel, alumina and its porous state, CoCr alloys, yttrium-stabilized zirconia (YSZ, zirconia-toughened alumina (ZTA, and cp Ti with the nanotubular TiO2 surface by finite element analysis (FEA under real cyclic biting loads and researches the optimum material for implant applications. For the analysis, the implant design generated by our group was utilized. The mechanical behavior and the life of the implant under biting loads were estimated based on the material and surface properties. According to the condition based on ISO 14801, the FEA results showed that the equivalent von Mises stress values were in the range of 226.95 MPa and 239.05 MPa. The penetration analysis was also performed, and the calculated penetration of the models onto the bone structure ranged between 0.0037389 mm and 0.013626 mm. L-605 CoCr alloy-assigned implant model showed the least penetration, while cp Ti with the nanotubular TiO2 surface led to the most one. However, the difference was about 0.01 mm, and it may not be evaluated as a distinct difference. As the final numerical evaluation item, the fatigue life was executed, and the results were achieved in the range of 4 × 105 and 1 × 109 cycles. These results indicated that different materials showed good performance for each evaluation component, but considering the overall mechanical performance and the treatment process (implant adsorption by means of surface properties, cp Ti with the nanotubular TiO2 surface material was evaluated as the suitable one, and it may also be implied that it displayed enough performance in the designed dental implant model.

Liquid crystalline epoxy nanocomposite material for dental application

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Yun-Yuan Tai

2015-01-01

Conclusion: The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment.

Dental ceramics: a review of new materials and processing methods

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Lucas Hian da SILVA

2017-08-01

Full Text Available Abstract The evolution of computerized systems for the production of dental restorations associated to the development of novel microstructures for ceramic materials has caused an important change in the clinical workflow for dentists and technicians, as well as in the treatment options offered to patients. New microstructures have also been developed by the industry in order to offer ceramic and composite materials with optimized properties, i.e., good mechanical properties, appropriate wear behavior and acceptable aesthetic characteristics. The objective of this literature review is to discuss the main advantages and disadvantages of the new ceramic systems and processing methods. The manuscript is divided in five parts: I monolithic zirconia restorations; II multilayered dental prostheses; III new glass-ceramics; IV polymer infiltrated ceramics; and V novel processing technologies. Dental ceramics and processing technologies have evolved significantly in the past ten years, with most of the evolution being related to new microstructures and CAD-CAM methods. In addition, a trend towards the use of monolithic restorations has changed the way clinicians produce all-ceramic dental prostheses, since the more aesthetic multilayered restorations unfortunately are more prone to chipping or delamination. Composite materials processed via CAD-CAM have become an interesting option, as they have intermediate properties between ceramics and polymers and are more easily milled and polished.

Investigation on adhering properties of dental materials by means of radioactively labelled bacteria

International Nuclear Information System (INIS)

Pfister, W.; Kleinert, P.; Sandig, H.C.; Wutzler, P.; Ruschitschka, A.; Schaefer, U.

1987-01-01

Bacteria of the species Streptococcus mutans were radioactively labelled with 113 In-oxinate. Different dental materials were incubated with the labelled bacteria. Counts per minute of the dental materials could be determined as proportion of the quantity of adhering microorganisms. Silver-palladium-alloy had a lower adherence than silver-tin-alloy. Finest polished alloys had lower adhering properties than unpolished surfaces of materials. (author)

Does a selection interview predict year 1 performance in dental school?

Science.gov (United States)

McAndrew, R; Ellis, J; Valentine, R A

2017-05-01

It is important for dental schools to select students who will complete their degree and progress on to become the dentists of the future. The process should be transparent, fair and ethical and utilise selection tools that select appropriate students. The interview is an integral part of UK dental schools student selection procedures. This study was undertaken in order to determine whether different interview methods (Cardiff with a multiple mini interview and Newcastle with a more traditional interview process) along with other components used in selection predicted academic performance in students. The admissions selection data for two dental schools (Cardiff and Newcastle) were collected and analysed alongside student performance in academic examinations in Year 1 of the respective schools. Correlation statistics were used to determine whether selection tools had any relevance to academic performance once students were admitted to their respective Universities. Data was available for a total of 177 students (77 Cardiff and 100 Newcastle). Examination performance did not correlate with admission interview scores at either school; however UKCAT score was linked to poor academic performance. Although interview methodology does not appear to correlate with academic performance it remains an integral and very necessary part of the admissions process. Ultimately schools need to be comfortable with their admissions procedures in attracting and selecting the calibre of students they desire. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Potentiometric stripping analysis of lead and cadmium leaching from dental prosthetic materials and teeth

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GORAN M. NIKOLIC

2004-07-01

Full Text Available Potentiometric stipping analysis (PSA was applied for the determination of lead and cadmium leaching from dental prosthetic materials and teeth. The soluble lead content in finished dental implants was found to be much lower than that of the individual components used for their preparation. Cadmium was not detected in dental implants and materials under the defined conditions. The soluble lead and cadmium content of teeth was slightly lower than the lead and cadmium content in whole teeth (w/w reported by other researchers, except in the case of a tooth with removed amalgam filling. The results of this work suggest that PSA may be a good method for lead and cadmium leaching studies for investigation of the biocompatibility of dental prosthetic materials.

3D printed versus conventionally cured provisional crown and bridge dental materials.

Science.gov (United States)

Tahayeri, Anthony; Morgan, MaryCatherine; Fugolin, Ana P; Bompolaki, Despoina; Athirasala, Avathamsa; Pfeifer, Carmem S; Ferracane, Jack L; Bertassoni, Luiz E

2018-02-01

To optimize the 3D printing of a dental material for provisional crown and bridge restorations using a low-cost stereolithography 3D printer; and compare its mechanical properties against conventionally cured provisional dental materials. Samples were 3D printed (25×2×2mm) using a commercial printable resin (NextDent C&B Vertex Dental) in a FormLabs1+ stereolithography 3D printer. The printing accuracy of printed bars was determined by comparing the width, length and thickness of samples for different printer settings (printing orientation and resin color) versus the set dimensions of CAD designs. The degree of conversion of the resin was measured with FTIR, and both the elastic modulus and peak stress of 3D printed bars was determined using a 3-point being test for different printing layer thicknesses. The results were compared to those for two conventionally cured provisional materials (Integrity ® , Dentsply; and Jet ® , Lang Dental Inc.). Samples printed at 90° orientation and in a white resin color setting was chosen as the most optimal combination of printing parameters, due to the comparatively higher printing accuracy (up to 22% error), reproducibility and material usage. There was no direct correlation between printing layer thickness and elastic modulus or peak stress. 3D printed samples had comparable modulus to Jet ® , but significantly lower than Integrity ® . Peak stress for 3D printed samples was comparable to Integrity ® , and significantly higher than Jet ® . The degree of conversion of 3D printed samples also appeared higher than that of Integrity ® or Jet ® . Our results suggest that a 3D printable provisional restorative material allows for sufficient mechanical properties for intraoral use, despite the limited 3D printing accuracy of the printing system of choice. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

PEEK with Reinforced Materials and Modifications for Dental Implant Applications

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Fitria Rahmitasari

2017-12-01

Full Text Available Polyetheretherketone (PEEK is a semi-crystalline linear polycyclic thermoplastic that has been proposed as a substitute for metals in biomaterials. PEEK can also be applied to dental implant materials as a superstructure, implant abutment, or implant body. This article summarizes the current research on PEEK applications in dental implants, especially for the improvement of PEEK surface and body modifications. Although various benchmark reports on the reinforcement and surface modifications of PEEK are available, few clinical trials using PEEK for dental implant bodies have been published. Controlled clinical trials, especially for the use of PEEK in implant abutment and implant bodies, are necessary.

Longevity of dental amalgam in comparison to composite materials

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Windisch, Friederike

2008-11-01

fillings in posterior teeth is difficult. Apart from the difficulties in conducting a randomized, controlled long-term study comparing the longevity of direct fillings, the fact that composites and adhesives used in a study have often already been replaced by the next generation of the product at the time of study publication presents an additional problem. Not only the filling material, but also patient parameters and local, intraoral factors (e. g. localisation of the filling as well as the treating dentist have an impact on the longevity of dental fillings. In evaluating economic studies, one has to refer to the heterogeneity of data on longevity in the medical evaluation. The only effect parameter used in the studies is longevity, other aspects (e. g. long-term functionality are only referred to in discussions. Extensive counselling of patients regarding the selection of the appropriate filling material is important. Conclusions: Amalgam fillings show a longer longevity than composite fillings. Two out of six systematic reviews conclude that the expected survival time of composite fillings can be comparable to amalgam fillings. However, these conclusions are based on the results of short-term studies which usually overestimate the longevity of filling materials. From an economic standpoint, amalgam is the more economic filling material compared to direct composite fillings in posterior teeth when considering longevity as the only result parameter. Other aspects than longevity need to be considered in individually choosing the appropriate dental filling material. For future studies aiming to compare the longevity of amalgam and composite fillings, a sufficient sample size and study period, preferably in the setting of a private dental practice, should be aimed for. An evaluation of the cost-effectiveness of amalgam and composite fillings should take the functionality of teeth over a longer time period into account, as well as patients’ preferences. The rapid

Equity in children's dental caries before and after cessation of community water fluoridation: differential impact by dental insurance status and geographic material deprivation.

Science.gov (United States)

McLaren, Lindsay; McNeil, Deborah A; Potestio, Melissa; Patterson, Steve; Thawer, Salima; Faris, Peter; Shi, Congshi; Shwart, Luke

2016-02-11

One of the main arguments made in favor of community water fluoridation is that it is equitable in its impact on dental caries (i.e., helps to offset inequities in dental caries). Although an equitable effect of fluoridation has been demonstrated in cross-sectional studies, it has not been studied in the context of cessation of community water fluoridation (CWF). The objective of this study was to compare the socio-economic patterns of children's dental caries (tooth decay) in Calgary, Canada, in 2009/10 when CWF was in place, and in 2013/14, after it had been discontinued. We analyzed data from population-based samples of schoolchildren (grade 2) in 2009/10 and 2013/14. Data on dental caries (decayed, missing, and filled primary and permanent teeth) were gathered via open mouth exams conducted in schools by registered dental hygienists. We examined the association between dental caries and 1) presence/absence of dental insurance and 2) small area index of material deprivation, using Poisson (zero-inflated) and logistic regression, for both time points separately. For small-area material deprivation at each time point, we also computed the concentration index of inequality for each outcome variable. Statistically significant inequities by dental insurance status and by small area material deprivation were more apparent in 2013/14 than in 2009/10. Results are consistent with increasing inequities in dental caries following cessation of CWF. However, further research is needed to 1) confirm the effects in a study that includes a comparison community, and 2) explore possible alternative reasons for the findings, including changes in treatment and preventive programming.

Liquid crystalline epoxy nanocomposite material for dental application.

Science.gov (United States)

Tai, Yun-Yuan; Hsu, Sheng-Hao; Chen, Rung-Shu; Su, Wei-Fang; Chen, Min-Huey

2015-01-01

Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment. Copyright © 2014. Published by Elsevier B.V.

Presence and leaching of bisphenol a (BPA) from dental materials

Science.gov (United States)

Becher, Rune; Wellendorf, Hanne; Sakhi, Amrit Kaur; Samuelsen, Jan Tore; Thomsen, Cathrine; Bølling, Anette Kocbach; Kopperud, Hilde Molvig

2018-01-01

Abstract BPA has been reported to leach from some resin based dental restorative materials and materials used for orthodontic treatment. To confirm and update previous findings, especially in light of the new temporary lower threshold value for tolerable daily BPA intake, we have investigated the leaching of BPA from 4 composite filling materials, 3 sealants and 2 orthodontic bonding materials. The materials were either uncured and dissolved in methanol or cured. The cured materials were kept in deionized water for 24 hours or 2 weeks. Samples were subsequently analyzed by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS-MS). The composite filling material Tetric EvoFlow® and the fissure sealant DELTON® showed significantly higher levels of BPA leaching compared to control samples for all test conditions (uncured, 24 h leaching and 2 weeks leaching). There were no significant differences in amount of leached BPA for any of the tested materials after 24 hours compared to 2 weeks. These results show that BPA is still released from some dental materials despite the general concern about potential adverse effects of BPA. However, the amounts of BPA were relatively low and most likely represent a very small contribution to the total BPA exposure. PMID:29868625

Bioactive and inert dental glass-ceramics.

Science.gov (United States)

Montazerian, Maziar; Zanotto, Edgar Dutra

2017-02-01

The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017. © 2016 Wiley Periodicals, Inc.

Endocrine disruptors and dental materials: health implications associated with their use in Brazil

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Coelho Antonio Jorge Molinário

2002-01-01

Full Text Available This study analyzes international historical trends in the use of different types of materials in dental practice. The author describes the chemical properties of their ingredients and the potential and observed adverse effects in patients and dental technicians resulting from clinical or occupational exposure to various metals like beryllium, used to produce metal alloys. The growing use of various products (resin cements, ionomer cements, aesthetic restorative materials, resins, endodontal cements, and others based on the compound bisphenol-A, whose chemical structure is similar to that of estrogen. Considering the demographic and contemporary work force characteristics of those involved in dental practice in the Brazil, the study highlights the possible effect of the use of these materials in both male and female patients and all age strata, as well as in health professionals with occupational exposure to products containing bisphenol-A.

Failure analysis of various monolithic posterior aesthetic dental crowns using finite element method

Science.gov (United States)

Porojan, Liliana; Topală, Florin

2017-08-01

The aim of the study was to assess the effect of material stiffness and load on the biomechanical performance of the monolithic full-coverage posterior aesthetic dental crowns using finite element analysis. Three restorative materials for monolithic dental crowns were selected for the study: zirconia; lithium disilicate glass-ceramic, and resin-based composite. Stresses were calculated in the crowns for all materials and in the teeth structures, under different load values. The experiments show that dental crowns made from all this new aesthetic materials processed by CAD/CAM technologies would be indicated as monolithic dental crowns for posterior areas.

Assessing the causes for the dentistry selection as a job by Iranian dental students: A Questionnaire Survey

Science.gov (United States)

Hamissi, J; Bairami, P; Hamissi, Z

2015-01-01

Objective: The purpose of the current research is to discover the causes for the dentistry selection as a profession by senior dental scholars in Iran. Materials & Methods: Surveys are distributed between the first-year to the sixth-year senior dental scholars at the Scholl of Dentistry in Medical Sciences Qazvin University in Iran. The survey presented in a lecture hall at the terminal of the secondary term in the 2011-2012 academic years. The survey included 30 parts, and the pupils asked to measure the significance of any part for choosing dentistry as a profession, on a 10-points scale. In addition, T-test and ANOVA utilized for the data analysis. Results: The answering ratio in the research is 55% (out of 100%) of the pupils delivered. Ninety-six students (93.2%) selected it as an initial selection. Dentistry as a job which is “insurer of financial independence” was gained a most rate via 82.5% of the pupils raised and a comparable amount of the students (75.7%), assigned a highest rate to the parameter “I love to enhance many money”. Dentistry as a “science-based job” was also given a score by 80.6% of the pupils. Conclusion: There are no variations in the motivation between men and women students. It obtained that “insurer of financial independence” and “I love to enhance many money” are critical action parameters in the dental pupils population. PMID:28316683

Performance of dental impression materials: Benchmarking of materials and techniques by three-dimensional analysis.

Science.gov (United States)

Rudolph, Heike; Graf, Michael R S; Kuhn, Katharina; Rupf-Köhler, Stephanie; Eirich, Alfred; Edelmann, Cornelia; Quaas, Sebastian; Luthardt, Ralph G

2015-01-01

Among other factors, the precision of dental impressions is an important and determining factor for the fit of dental restorations. The aim of this study was to examine the three-dimensional (3D) precision of gypsum dies made using a range of impression techniques and materials. Ten impressions of a steel canine were fabricated for each of the 24 material-method-combinations and poured with type 4 die stone. The dies were optically digitized, aligned to the CAD model of the steel canine, and 3D differences were calculated. The results were statistically analyzed using one-way analysis of variance. Depending on material and impression technique, the mean values had a range between +10.9/-10.0 µm (SD 2.8/2.3) and +16.5/-23.5 µm (SD 11.8/18.8). Qualitative analysis using colorcoded graphs showed a characteristic location of deviations for different impression techniques. Three-dimensional analysis provided a comprehensive picture of the achievable precision. Processing aspects and impression technique were of significant influence.

Osteogenic differentiation of dental pulp stem cells under the influence of three different materials

DEFF Research Database (Denmark)

Ajlan, S. A.; Ashri, N. Y.; Aldahmash, Abdullah M.

2015-01-01

Background: Regeneration of periodontal tissues is a major goal of periodontal therapy. Dental pulp stem cells (DPSCs) show mesenchymal cell properties with the potential for dental tissue engineering. Enamel matrix derivative (EMD) and platelet-derived growth factor (PDGF) are examples of materi......Background: Regeneration of periodontal tissues is a major goal of periodontal therapy. Dental pulp stem cells (DPSCs) show mesenchymal cell properties with the potential for dental tissue engineering. Enamel matrix derivative (EMD) and platelet-derived growth factor (PDGF) are examples...

The Relative Patient Costs and Availability of Dental Services, Materials and Equipment in Public Oral Care Facilities in Tanzania.

OpenAIRE

Nyamuryekung'e, Kasusu K; Lahti, Satu M; Tuominen, Risto J

2015-01-01

Background Patient charges and availability of dental services influence utilization of dental services. There is little available information on the cost of dental services and availability of materials and equipment in public dental facilities in Africa. This study aimed to determine the relative cost and availability of dental services, materials and equipment in public oral care facilities in Tanzania. The local factors affecting availability were also studied. Methods A survey of all dis...

Dimensional changes of alginate dental impression materials.

Science.gov (United States)

Nallamuthu, N; Braden, M; Patel, M P

2006-12-01

The weight loss and corresponding dimensional changes of two dental alginate impression materials have been studied. The weight loss kinetics indicate this to be a diffusion controlled process, but with a boundary condition at the surface of the concentration decreasing exponentially with time. This is in marked contrast to most desorption processes, where the surface concentration becomes instantaneously zero. The appropriate theory has been developed for an exponential boundary condition, and its predictions compared with experimental data; the agreement was satisfactory. The diffusion coefficients for two thicknesses of the same material were not identical as predicted by theory; the possible reasons for this are discussed.

75 FR 16511 - Pentron Clinical Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental...

Science.gov (United States)

2010-04-01

... produce dental materials such as dental prosthetics, dental composites, dental impressions, dental... materials such as dental prosthetics, dental composites, dental impressions, dental adhesives, and other... Technologies, a Wholly-Owned Subsidiary of Kerr Dental/Sybron Dental Specialities, Formally Known as Customedix...

Determination of dose rates from natural radionuclides in dental materials

International Nuclear Information System (INIS)

Veronese, I.; Guzzi, G.; Giussani, A.; Cantone, M.C.; Ripamonti, D.

2006-01-01

Different types of materials used for dental prosthetics restoration, including feldspathic ceramics, glass ceramics, zirconia-based ceramics, alumina-based ceramics, and resin-based materials, were investigated with regard to content of natural radionuclides by means of thermoluminescence beta dosimetry and gamma spectrometry. The gross beta dose rate from feldspathic and glass ceramics was about ten times higher than the background measurement, whereas resin-based materials generated negligible beta dose rate, similarly to natural tooth samples. The specific activity of uranium and thorium was significantly below the levels found in the period when addition of uranium to dental porcelain materials was still permitted. The high-beta dose levels observed in feldspathic porcelains and glass ceramics are thus mainly ascribable to 4 K, naturally present in these specimens. Although the measured values are below the recommended limits, results indicate that patients with prostheses are subject to higher dose levels than other members of the population. Alumina- and zirconia-based ceramics might be a promising alternative, as they have generally lower beta dose rates than the conventional porcelain materials. However, the dosimetry results, which imply the presence of inhomogeneously distributed clusters of radionuclides in the sample matrix, and the still unsuitable structural properties call for further optimization of these materials

Dental Amalgam

Science.gov (United States)

... Products and Medical Procedures Dental Devices Dental Amalgam Dental Amalgam Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Dental amalgam is a dental filling material which is ...

Prevalence and distribution of selected dental anomalies among saudi children in Abha, Saudi Arabia.

Science.gov (United States)

Yassin, Syed M

2016-12-01

Dental anomalies are not an unusual finding in routine dental examination. The effect of dental anomalies can lead to functional, esthetic and occlusal problems. The Purpose of the study was to determine the prevalence and distribution of selected developmental dental anomalies in Saudi children. The study was based on clinical examination and Panoramic radiographs of children who visited the Pediatric dentistry clinics at King Khalid University College of Dentistry, Saudi Arabia. These patients were examined for dental anomalies in size, shape, number, structure and position. Data collected were entered and analyzed using statistical package for social sciences version. Of the 1252 children (638 Boys, 614 girls) examined, 318 subjects (25.39%) presented with selected dental anomalies. The distribution by gender was 175 boys (27.42%) and 143 girls (23.28%). On intergroup comparison, number anomalies was the most common anomaly with Hypodontia (9.7%) being the most common anomaly in Saudi children, followed by hyperdontia (3.5%). The Prevalence of size anomalies were Microdontia (2.6%) and Macrodontia (1.8%). The prevalence of Shape anomalies were Talon cusp (1.4%), Taurodontism (1.4%), Fusion (0.8%).The prevalence of Positional anomalies were Ectopic eruption (2.3%) and Rotation (0.4%). The prevalence of structural anomalies were Amelogenesis imperfecta (0.3%) Dentinogenesis imperfecta (0.1%). A significant number of children had dental anomaly with Hypodontia being the most common anomaly and Dentinogenesis imperfecta being the rare anomaly in the study. Early detection and management of these anomalies can avoid potential orthodontic and esthetic problems in a child. Key words: Dental anomalies, children, Saudi Arabia.

Fatigue Testing of Dental Bridges on Selected Examples

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Urban Dariusz

2017-03-01

Full Text Available The paper presents example tests of the functional quality of selected designs of dental bridges. These were: porcelain bridges on a metal base (cobalt based alloy, porcelain bridges on a zirconia base (zirconia ceramic – Zirkon Zahn, and full zirconia bridges (Zirkon Zahn. For the purpose of the study, durability of bridges in cyclic fatigue testing was adopted as a measure of their quality. The tests were carried out on a Zwick Roell Z010 universal testing machine. They consisted in cyclic loading and unloading of dental bridges mounted on gypsum models at a loading force of F= 400 [N] and a frequency of load of f= 1 [Hz]. Each bridge was subjected to a cycle of 7200 loads. The results show that there are no significant differences in the functional quality of the bridges.

IN VITRO TESTING – AN ESENTIAL METHOD FOR EVALUATING THE PERFORMANCE OF DENTAL MATERIALS AND DEVICES

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Anca VIŢALARIU

2015-06-01

Full Text Available Dentistry is unique among biomaterials specialties as to the large variety of materials used, and nature of the challenges they must resist. Intra-oral service demands materials adapted to a warm and moist environment, resisting the attack of digestive acids and enzymes. The materials subjected to mechanical forces should preserve their strength, fatigue and wear characteristics, for accomplishing their function. The wide range of materials available for restorative dentistry demands knowledge of their relative strengths and trade-offs, and offers the opportunity for many interesting lines of research. The spectrum extensively ranges from elastic impression materials to extremely stiff metal and ceramic appliances, so that familiarity with a variety of mechanical testing situations is required from a well-rounded dental materials laboratory. Evaluating the mechanical and wear characteristics of dental restorative materials and analyzing the durability of adhesives is critical to the development of improved dental devices

[Clinical and microbiological study regarding surface antibacterial properties of bioactive dental materials].

Science.gov (United States)

Târcă, T; Bădescu, Aida; Topoliceanu, C; Lăcătuşu, St

2010-01-01

In the new era of dentistry the coronal restoration materials must possess "bio-active" features represented by fluor ions release, chemical adhesion and antibacterial agents. Our study aims to determine the surface antibacterial properties of glassionomer cements and compomers. The study group included 64 patients with high cariogenic risk with 80 teeth with acute and chronic dental caries affecting proximal and occlusal dental surfaces. The teeth with cariogenic lesions were restored with zinc-oxide-eugenol (n=20), glassionomer cement GC Fuji Triage (n=20), glassionomer cement modified with resins Fuji II LC (n=20), compomer Dyract (n=20). DENTOCULT SM test (Orion Diagnostica, Finland) was used for bacterial analyses. The samples from bacterial biofilm were collected from the restorated dental surfaces (study group) and intact enamel surfaces (control group). The recorded data were processed using non-parametrical statistical tests. The lowest mean value of bacterial indices was recorded for glassionomer cement Fuji Triage (0.4), and Fuji II LC (1.2), material with highest surface antibacterial properties. The highest value (1.5) was recorded for compomer Dyract. The Kruskal-Wallis test proves the significant statistical differences between the three bioactive materials. The materials with bioactive features have the ability to inhibate the growth of Streptococcus mutans in bacterial biofilm to the surfaces of coronal restoration.

Syllabus of Dental Materials

Science.gov (United States)

1984-07-01

Rubberloid Van R Dental Prod. Surgident Lactona Corp. Alginates Coe Alginate Coe Labs o Jeltrate L.D. Caulk Kerr Alginate Kerr/Sybron Alginate S.S. White Co...Surgident- Alginate Lactona Corp. Unijel II Unitek Corp. O Combination Agar/a ig inate Colloid 80 U.S. Shiza Corp. Dentloid Denterials, Ltd...66061 (215) 277-3800 (913) 782-2200 Shofu Dental Corp. Lactona Corp. (subsidary of 4025 Bohannon Dr. Warner-Lambert Co.) Menlo Park, CA 94025 . Academy

Why do adults entitled to free or highly subsidized dental services select fully out-of-pocket-paid care?

Science.gov (United States)

Bayat, Fariborz; Vehkalahti, Miira M; Murtomaa, Heikki; Tala, Heikki

2010-02-01

To investigate patients' reasons for selecting a dental clinic given their choice of free or highly-subsidized dental services. The study was based on cross-sectional data obtained through phone interviews with adults in Tehran, Iran. The present study included those entitled to free or highly-subsidized dental services (n = 726). The data covered the patients' awareness of subsidized dental services and type of dental clinic for their most recent visit and their reasons for selecting that clinic. Awareness of subsidized dental services was dichotomized as being either aware or unaware of such subsidy. The type of clinic was dichotomized as providing either free or highly-subsidized (FHS) or fully out-of-pocket paid (FOP) services. Free format answers about the subjects' reasons for selecting a particular clinic were later sub-grouped as: convenient access, good technical aspects, good interpersonal aspects, low or reasonable fees, recommendation by a friend, and no reason. Socio-demographic status was based on background. Data analysis included the chi-square test and logistic regression model. Of the subjects (n = 726), 60% were women and 58% were under 35 years of age. The subjects' mean age was 33.5 years with no difference by gender (P = 0.24) and the majority had public insurance (91%). Of all the subjects, 60% selected FOP. Good interpersonal aspects were the strongest reason for selecting FOP (OR = 4.6), follow by good technical aspects (OR = 2.3). Those subjects who were unaware of their benefit had 4.6 times the odds of selecting FOP. Despite the opportunity to use highly-subsidized dental services, good interpersonal and good technical aspects lead patients to select private dentists and to pay fully out of pocket.

Two- and three-dimensional accuracy of dental impression materials: effects of storage time and moisture contamination.

Science.gov (United States)

Chandran, Deepa T; Jagger, Daryll C; Jagger, Robert G; Barbour, Michele E

2010-01-01

Dental impression materials are used to create an inverse replica of the dental hard and soft tissues, and are used in processes such as the fabrication of crowns and bridges. The accuracy and dimensional stability of impression materials are of paramount importance to the accuracy of fit of the resultant prosthesis. Conventional methods for assessing the dimensional stability of impression materials are two-dimensional (2D), and assess shrinkage or expansion between selected fixed points on the impression. In this study, dimensional changes in four impression materials were assessed using an established 2D and an experimental three-dimensional (3D) technique. The former involved measurement of the distance between reference points on the impression; the latter a contact scanning method for producing a computer map of the impression surface showing localised expansion, contraction and warpage. Dimensional changes were assessed as a function of storage times and moisture contamination comparable to that found in clinical situations. It was evident that dimensional changes observed using the 3D technique were not always apparent using the 2D technique, and that the former offers certain advantages in terms of assessing dimensional accuracy and predictability of impression methods. There are, however, drawbacks associated with 3D techniques such as the more time-consuming nature of the data acquisition and difficulty in statistically analysing the data.

Evaluation of simulation learning materials use to fill the gap in Japanese dental English education.

Science.gov (United States)

Seki, Naoko; Moross, Janelle; Sunaga, Masayo; Hobo, Koki; Miyoshi, Tomoe; Nitta, Hiroshi; Kinoshita, Atsuhiro; Morio, Ikuko

2016-01-01

Even though English is most frequently the common language when the patient's native language differs from that of a dentist, the opportunities for Japanese undergraduate dental students to learn dental English are now quite limited. The purposes of our study were to investigate: the effectiveness and feasibility of the computer-assisted simulation materials as one solution strategy for dental English education in Japan, and the needs and demands for dental English from the learners' side. Interactive simulation materials for medical interviews in English and clinical cases which were translated to English, were delivered via Learning Management System (LMS) to nineteen trainee residents of dentistry (residents). Evaluation for the materials, learners' knowledge and interests in the contents, and ease of operation were obtained by post-questionnaire (response rates were 100% and 95%, respectively). Both questionnaire-surveys received positive feedback toward the materials, yet 47% answered that they lacked the level of knowledge about contents of the medical interview in English. Results were sufficient to suggest that the residents would like to have the opportunity to study or practice medical interview in English, or English related to dentistry, and that the simulation materials could be one of the solution strategies for opportunity provision.

Defects-tolerant Co-Cr-Mo dental alloys prepared by selective laser melting.

Science.gov (United States)

Qian, B; Saeidi, K; Kvetková, L; Lofaj, F; Xiao, C; Shen, Z

2015-12-01

CrCoMo alloy specimens were successfully fabricated using selective laser melting (SLM). The aim of this study was to carefully investigate microstructure of the SLM specimens in order to understand the influence of their structural features inter-grown on different length scales ranging from nano- to macro-levels on their mechanical properties. Two different sets of processing parameters developed for building the inner part (core) and the surface (skin) of dental prostheses were tested. Microstructures were characterized by SEM, EBSD and XRD analysis. The elemental distribution was assessed by EDS line profile analysis under TEM. The mechanical properties of the specimens were measured. The microstructures of both specimens were characterized showing formation of grains comprised of columnar sub-grains with Mo-enrichment at the sub-grain boundaries. Clusters of columnar sub-grains grew coherently along one common crystallographic direction forming much larger single crystal grains which are intercrossing in different directions forming an overall dendrite-like microstructure. Three types of microstructural defects were occasionally observed; small voids (10 μm). Despite the presence of these defects, the yield and the ultimate tensile strength (UTS) were 870 and 430MPa and 1300MPa and 1160MPa, respectively, for the skin and core specimens which are higher than casted dental alloy. Although the formation of microstructural defects is hard to be avoided during the SLM process, the SLM CoCrMo alloys can achieve improved mechanical properties than their casted counterparts, implying they are "defect-tolerant". Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Measurement of absorbed doses near metal and dental material interfaces irradiated by x- and gamma-ray therapy beams

International Nuclear Information System (INIS)

Farahani, M.; Eichmiller, F.C.; McLaughlin, W.L.

1990-01-01

Soft-tissue damage adjacent to dental restorations is a deleterious side effect of radiation therapy associated with low-energy electron scatter from dental materials of high electron density. This study was designed to investigate the enhancement of dose to soft tissue (or water) close to high electron-density materials and to measure the detailed lateral and depth-dose profiles in soft-tissue-simulating polymer adjacent to planar interfaces of several higher atomic-number materials: 18-carat gold dental casting alloy; Ag-Hg dental amalgam alloy; Ni-Cr dental casting alloy; and natural human tooth structure. Results indicate that the dose-enhancement in 'tissue' is as great as a factor of 2 on the backscatter side adjacent to gold and a factor of 1.2 adjacent to tooth tissue, but is insignificant on the forward-scatter side because of the predominant effect of attenuation by the high-density, high atomic-number absorbing material. (author)

Shade selection performed by novice dental professionals and colorimeter.

Science.gov (United States)

Klemetti, E; Matela, A-M; Haag, P; Kononen, M

2006-01-01

The objective of this study was to test inter-observer variability in shade selection for porcelain restorations, using three different shade guides: Vita Lumin Vacuum, Vita 3D-Master and Procera. Nineteen young dental professionals acted as observers. The results were also compared with those of a digital colorimeter (Shade Eye Ex; Shofu, Japan). Regarding repeatability, no significant differences were found between the three shade guides, although repeatability was relatively low (33-43%). Agreement with the colorimetric results was also low (8-34%). In conclusion, shade selection shows moderate to great inter-observer variation. In teaching and standardizing the shade selection procedure, a digital colorimeter may be a useful educational tool.

Considerations for services from dental technicians in fabrication of fixed prostheses: A survey of commercial dental laboratories in Thessaloniki, Greece.

Science.gov (United States)

Hatzikyriakos, Andreas; Petridis, Haralampos P; Tsiggos, Nikolaos; Sakelariou, Sotirios

2006-11-01

Effective communication and cooperation between dentists and dental technicians are essential in providing quality services. There has been a lack of information regarding dentist-dental technician communications and current methods and materials used for the fabrication of fixed partial dentures (FPDs). This cross-sectional study identified the materials and techniques used for fabrication of FPDs, as well as the status of communication between dentists and dental technicians in Thessaloniki, Greece. A questionnaire was developed with 7 sections pertaining to procedures and materials used for the fabrication of fixed prostheses: general questions, infection control, impressions/interocclusal records, die technique/mounting, information from final casts, prostheses design/materials, and communication/shade selection. The questionnaire was anonymous and distributed by the Association of Dental Technicians of Thessaloniki to all member laboratories (228) in the wider province of Thessaloniki, Greece. Due to the absence of normal distribution of the results, frequencies and medians were reported. Ninety-six of 228 dental laboratories responded (42.1% response rate). Twenty-six percent of dental laboratories did not routinely disinfect incoming items. The dental technicians considered 30% of incoming final impressions and 20% of interocclusal registrations as inadequate. Half of the time (55%) final casts were mounted by technicians on simple hinge articulators. Only 20% of tooth preparations had adequate finish lines. The majority (70%) of fixed restorations were metal-ceramic. Fifty-seven percent of dental technicians considered the delivery time requested by dentists as insufficient. The information provided in this study indicates areas of weakness in communication between dentists and dental technicians, along with areas where both parties should use greater care during clinical and laboratory procedures.

The dosimetric impact of dental implants on head-and-neck volumetric modulated arc therapy

International Nuclear Information System (INIS)

Lin, Mu-Han; Li Jinsheng; Price, Robert A Jr; Wang Lu; Ma, C-M; Lee, Chung-Chi

2013-01-01

This work aims to investigate the dosimetric impact of dental implants on volumetric modulated arc therapy (VMAT) for head-and-neck patients and to evaluate the effectiveness of using the material's electron-density ratio for the correction. An in-house Monte Carlo (MC) code was utilized for the dose calculation to account for the scattering and attenuation caused by the high-Z implant material. Three different dental implant materials were studied in this work: titanium, Degubond®4 and gold. The dose perturbations caused by the dental implant materials were first investigated in a water phantom with a 1 cm 3 insert. The per cent depth dose distributions of a 3 × 3 cm 2 photon field were compared with the insert material as water and the three selected dental implant materials. To evaluate the impact of the dental implant on VMAT patient dose calculation, four head-and-neck cases were selected. For each case, the VMAT plan was designed based on the artifact-corrected patient geometry using a treatment planning system (TPS) that was typically utilized for routine patient treatment. The plans were re-calculated using the MC code for five situations: uncorrected geometry, artifact-corrected geometry and artifact-corrected geometry with one of the three different implant materials. The isodose distributions and the dose–volume histograms were cross-compared with each other. To evaluate the effectiveness of using the material's electron-density ratio for dental implant correction, the implant region was set as water with the material's electron-density ratio and the calculated dose was compared with the MC simulation with the real material. The main effect of the dental implant was the severe attenuation in the downstream. The 1 cm 3 dental implant can lower the downstream dose by 10% (Ti) to 51% (Au) for a 3 × 3 cm 2 field. The TPS failed to account for the dose perturbation if the dental implant material was not precisely defined. For the VMAT patient dose

Novel surface coating materials for endodontic dental implant

International Nuclear Information System (INIS)

Fathi, M.H.; Mortazavi, V.; Moosavi, S.B.

2003-01-01

The aim of this study was to design and produce novel coating materials in order to obtain two goals including; improvement of the corrosion behavior of metallic dental endodontic implant and the bone osteointegration simultaneously. Stainless steel 316L (SS) was used as a metallic substrate and a novel Hydroxyapatite/Titanium (HA/Ti) composite coating was prepared on it. Structural characterization techniques including XRD, SEM and EDX were utilized to investigate the microstructure and morphology of the coating. Electrochemical tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. Two types of endodontic implants including; SS with and without (HA/Ti) composite coating were prepared and subsequently implanted in the mandibular canine of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, osteointegration evaluation and histopathological interpretation was carried out using SEM and optical microscopy. Results indicate that the novel HA/Ti composite coating improves the corrosion behavior and biocompatibility of SS endodontic dental implant. The clinical evaluation (in vivo test) results showed that there was significant difference in osteointegration between coated and uncoated endodontic dental implants and average bone osteointegration of coated implants were more than uncoated implants. The histopathological results and bone tissue response to the coated implants was acceptable and it was concluded that HA/Ti composite coated SS could be used as well as an endodontic dental implant. (author)

Effect of Dental Restorative Material Type and Shade on Characteristics of Two-Layer Dental Composite Systems

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Atefeh Karimzadeh

Full Text Available Abstract The purpose of this study was to investigate the effects of shade and material type and shape in dental polymer composites on the hardness and shrinkage stress of bulk and two-layered restoration systems. For this purpose, some bulk and layered specimens from three different shades of dental materials were prepared and light-cured. The experiments were carried out on three types of materials: conventional restorative composite, nanohybrid composite and nanocomposite. Micro-indentation experiment was performed on the bulk and also on each layer of layered restoration specimens using a Vicker's indenter. The interface between the two layers was studied by scanning electron microscopy (SEM. The results revealed significant differences between the values of hardness for different shades in the conventional composite and also in the nanohybrid composite. However, no statistically significant difference was observed between the hardness values for different shades in the nanocomposite samples. The layered restoration specimens of different restorative materials exhibited lower hardness values with respect to their bulk specimens. The reduction in the hardness value of the layered conventional composite samples was higher than those of the nanocomposite and nanohybrid composite specimens indicating more shrinkage stresses generated in the conventional composite restorations. According to the SEM images, a gap was observed between the two layers in the layered restorations.

SU-F-T-426: Measurement of Dose Enhancement Due to Backscatter From Modern Dental Materials

International Nuclear Information System (INIS)

Hurwitz, M; Margalit, D; Williams, C; Tso, T; Lee, S; Rosen, E

2016-01-01

Purpose: High-density materials used in dental restoration can cause significant localized dose enhancement due to electron backscatter in head-and-neck radiotherapy, increasing the risk of mucositis. The materials used in prosthetic dentistry have evolved in the last decades from metal alloys to ceramics. We aim to determine the dose enhancement caused by backscatter from currently-used dental materials. Methods: Measurements were performed for three different dental materials: lithium disilicate (Li 2 Si 2 O 5 ), zirconium dioxide (ZrO 2 ), and gold alloy. Small thin squares (2×2×0.15 cm 3 ) of the material were fabricated, and placed into a phantom composed of tissue-equivalent material. The phantom was irradiated with a single 6 MV photon field. A thin-window parallel-plate ion chamber was used to measure the dose at varying distances from the proximal interface between the material and the plastic. Results: The dose enhancement at the interface between the high-density and tissue-equivalent materials, relative to a homogeneous phantom, was 54% for the gold alloy, 31% for ZrO 2 , and 9% for Li 2 Si 2 O 5 . This enhancement decreased rapidly with distance from the interface, falling to 11%, 5%, and 0.5%, respectively, 2 mm from the interface. Comparisons with the modeling of this effect in treatment planning systems are performed. Conclusion: While dose enhancement due to dental restoration is smaller with ceramic materials than with metal alloys, it can still be significant. A spacer of about 2–3 mm would be effective in reducing this enhancement, even for metal alloys.

SU-F-T-426: Measurement of Dose Enhancement Due to Backscatter From Modern Dental Materials

Energy Technology Data Exchange (ETDEWEB)

Hurwitz, M; Margalit, D; Williams, C [Brigham and Women’s Hospital / Harvard Medical School, Boston, MA (United States); Tso, T; Lee, S; Rosen, E [Harvard School of Dental Medicine, Boston, MA (United States)

2016-06-15

Purpose: High-density materials used in dental restoration can cause significant localized dose enhancement due to electron backscatter in head-and-neck radiotherapy, increasing the risk of mucositis. The materials used in prosthetic dentistry have evolved in the last decades from metal alloys to ceramics. We aim to determine the dose enhancement caused by backscatter from currently-used dental materials. Methods: Measurements were performed for three different dental materials: lithium disilicate (Li{sub 2}Si{sub 2}O{sub 5}), zirconium dioxide (ZrO{sub 2}), and gold alloy. Small thin squares (2×2×0.15 cm{sup 3}) of the material were fabricated, and placed into a phantom composed of tissue-equivalent material. The phantom was irradiated with a single 6 MV photon field. A thin-window parallel-plate ion chamber was used to measure the dose at varying distances from the proximal interface between the material and the plastic. Results: The dose enhancement at the interface between the high-density and tissue-equivalent materials, relative to a homogeneous phantom, was 54% for the gold alloy, 31% for ZrO{sub 2}, and 9% for Li{sub 2}Si{sub 2}O{sub 5}. This enhancement decreased rapidly with distance from the interface, falling to 11%, 5%, and 0.5%, respectively, 2 mm from the interface. Comparisons with the modeling of this effect in treatment planning systems are performed. Conclusion: While dose enhancement due to dental restoration is smaller with ceramic materials than with metal alloys, it can still be significant. A spacer of about 2–3 mm would be effective in reducing this enhancement, even for metal alloys.

Backscattering from dental restorations and splint materials during therapeutic radiation

International Nuclear Information System (INIS)

Farman, A.G.; Sharma, S.; George, D.I.; Wilson, D.; Dodd, D.; Figa, R.; Haskell, B.

1985-01-01

Models were constructed to simulate as closely as possible the human oral cavity. Radiation absorbed doses were determined for controls and various test situations involving the presence of dental restorative and splint materials during cobalt-60 irradiation of the models. Adjacent gold full crowns and adjacent solid dental silver amalgam cores both increased the dose to the interproximal gingivae by 20%. Use of orthodontic full bands for splinting the jaws increased the dose to the buccal tissues by an average of 10%. Augmentation of dose through backscatter radiation was determined to be only slight for intracoronal amalgam fillings and stainless steel or plastic bracket splints

Graduate and Undergraduate Geriatric Dentistry Education in a Selected Dental School in Japan

Science.gov (United States)

Kitagawa, Noboru; Sato, Yuji; Komabayashi, Takashi

2010-01-01

Geriatric dentistry and its instruction are critical in a rapidly aging population. Japan is the world’s fastest-aging society, and thus geriatric dentistry education in Japan can serve as a global model for other countries that will soon encounter the issues that Japan has already confronted. This study aimed to evaluate geriatric dental education with respect to the overall dental education system, undergraduate geriatric dentistry curricula, mandatory internships, and graduate geriatric education of a selected dental school in Japan. Bibliographic data and local information were collected. Descriptive and statistical analyses (Fisher and Chi-square test) were conducted. Japanese dental schools teach geriatric dentistry in 10 geriatric dentistry departments as well as in prosthodontic departments. There was no significant differences found between the number of public and private dental schools with geriatric dentistry departments (p = 0.615). At Showa University School of Dentistry, there are more didactic hours than practical training hours; however, there is no significant didactic/practical hour distribution difference between the overall dental curriculum and fourth-year dental students’ geriatric dental education curriculum (p=0.077). Graduate geriatric education is unique because it is a four-year Ph.D. course of study; there is neither a Master’s degree program nor a certificate program in Geriatric Dentistry. Overall, both undergraduate and graduate geriatric dentistry curricula are multidisciplinary. This study contributes to a better understanding of geriatric dental education in Japan; the implications of this study include developing a clinical/didactic curriculum, designing new national/international dental public health policies, and calibrating the competency of dentists in geriatric dentistry. PMID:21985207

An in vitro study of dental enamel wear by restorative materials using radiometric method

International Nuclear Information System (INIS)

Adachi, Lena Katekawa

2000-01-01

There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

Advances in dental veneers: materials, applications, and techniques.

Science.gov (United States)

Pini, Núbia Pavesi; Aguiar, Flávio Henrique Baggio; Lima, Débora Alves Nunes Leite; Lovadino, José Roberto; Terada, Raquel Sano Suga; Pascotto, Renata Corrêa

2012-01-01

Laminate veneers are a conservative treatment of unaesthetic anterior teeth. The continued development of dental ceramics offers clinicians many options for creating highly aesthetic and functional porcelain veneers. This evolution of materials, ceramics, and adhesive systems permits improvement of the aesthetic of the smile and the self-esteem of the patient. Clinicians should understand the latest ceramic materials in order to be able to recommend them and their applications and techniques, and to ensure the success of the clinical case. The current literature was reviewed to search for the most important parameters determining the long-term success, correct application, and clinical limitations of porcelain veneers.

Potential countersample materials for in vitro simulation wear testing.

Science.gov (United States)

Shortall, Adrian C; Hu, Xiao Q; Marquis, Peter M

2002-05-01

Any laboratory investigation of the wear resistance of dental materials needs to consider oral conditions so that in vitro wear results can be correlated with in vivo findings. The choice of the countersample is a critical factor in establishing the pattern of tribological wear and in achieving an efficient in vitro wear testing system. This research investigated the wear behavior and surface characteristics associated with three candidate countersample materials used for in vitro wear testing in order to identify a possible suitable substitute for human dental enamel. Three candidate materials, stainless steel, steatite and dental porcelain were evaluated and compared to human enamel. A variety of factors including hardness, wear surface evolution and frictional coefficients were considered, relative to the tribology of the in vivo situation. The results suggested that the dental porcelain investigated bore the closest similarity to human enamel of the materials investigated. Assessment of potential countersample materials should be based on the essential tribological simulation supported by investigations of mechanical, chemical and structural properties. The selected dental porcelain had the best simulating ability among the three selected countersample materials and this class of material may be considered as a possible countersample material for in vitro wear test purposes. Further studies are required, employing a wider range of dental ceramics, in order to optimise the choice of countersample material for standardized in vitro wear testing.

Effects of Ceramic Density and Sintering Temperature on the Mechanical Properties of a Novel Polymer-Infiltrated Ceramic-Network Zirconia Dental Restorative (Filling) Material.

Science.gov (United States)

Li, Weiyan; Sun, Jian

2018-05-10

BACKGROUND Polymer-infiltrated ceramic-network (PICN) dental material is a new and practical development in orthodontics. Sintering is the process of forming a stable solid mass from a powder by heating without melting. The aim of this study was to evaluate the effects of sintering temperature on the mechanical properties of a PICN zirconia dental material. MATERIAL AND METHODS A dense zirconia ceramic and four PICN zirconia dental materials, with varying porosities, were sintered at three different temperatures; 12 PICN zirconia dental materials based on these porous ceramics were prepared, as well as a pure polymer. After the specimen preparation, flexural strength and elastic modulus values were measured using the three-point bending test, and fracture toughness were determined by the single-edge notched beam (SENB) method. The Vickers hardness test method was used with an indentation strength (IS) test. Scanning electron microscopy (SEM) was used to examine the microstructure of the ceramic surface and the fracture surface. RESULTS Mechanical properties of the PICN dental materials, including flexural strength, elastic modulus, fracture toughness, and hardness, were more similar to the properties of natural teeth when compared with traditional dental ceramic materials, and were affected by the density and sintering temperature. SEM showed that the porous ceramic network became cohesive and that the length of cracks in the PICN dental material was reduced. CONCLUSIONS PICN zirconia dental materials were characterized by similar mechanical properties to natural dental tissues, but further studies are required continue to improve the similarities with natural human enamel and dentin.

Patients' satisfaction with dental care provided by public dental ...

African Journals Online (AJOL)

Background: In Tanzania, patient satisfaction with dental services has received only minor attention. Objective: To assess patients' satisfaction with public dental health services in Dar es Salaam. Design: A cross-sectional study. Setting: Five public dental clinics randomly selected from a list of all the nine public dental ...

Chemical Differentiation of Osseous, Dental, and Non-skeletal Materials in Forensic Anthropology using Elemental Analysis.

Science.gov (United States)

Zimmerman, Heather A; Meizel-Lambert, Cayli J; Schultz, John J; Sigman, Michael E

2015-03-01

Forensic anthropologists are generally able to identify skeletal materials (bone and tooth) using gross anatomical features; however, highly fragmented or taphonomically altered materials may be problematic to identify. Several chemical analysis techniques have been shown to be reliable laboratory methods that can be used to determine if questionable fragments are osseous, dental, or non-skeletal in nature. The purpose of this review is to provide a detailed background of chemical analysis techniques focusing on elemental compositions that have been assessed for use in differentiating osseous, dental, and non-skeletal materials. More recently, chemical analysis studies have also focused on using the elemental composition of osseous/dental materials to evaluate species and provide individual discrimination, but have generally been successful only in small, closed groups, limiting their use forensically. Despite significant advances incorporating a variety of instruments, including handheld devices, further research is necessary to address issues in standardization, error rates, and sample size/diversity. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Dental Glass Ionomer Cements as Permanent Filling Materials? – Properties, Limitations and Future Trends

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Ulrich Lohbauer

2009-12-01

Full Text Available Glass ionomer cements (GICs are clinically attractive dental materials that have certain unique properties that make them useful as restorative and luting materials. This includes adhesion to moist tooth structures and base metals, anticariogenic properties due to release of fluoride, thermal compatibility with tooth enamel, biocompatibility and low toxicity. The use of GICs in a mechanically loaded situation, however, has been hampered by their low mechanical performance. Poor mechanical properties, such as low fracture strength, toughness and wear, limit their extensive use in dentistry as a filling material in stress-bearing applications. In the posterior dental region, glass ionomer cements are mostly used as a temporary filling material. The requirement to strengthen those cements has lead to an ever increasing research effort into reinforcement or strengthening concepts.

Recent advances and developments in composite dental restorative materials.

Science.gov (United States)

Cramer, N B; Stansbury, J W; Bowman, C N

2011-04-01

Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance.

Could situational judgement tests be used for selection into dental foundation training?

Science.gov (United States)

Patterson, F; Ashworth, V; Mehra, S; Falcon, H

2012-07-13

To pilot and evaluate a machine-markable situational judgement test (SJT) designed to select candidates into UK dental foundation training. Single centre pilot study. UK postgraduate deanery in 2010. Seventy-four candidates attending interview for dental foundation training in Oxford and Wessex Deaneries volunteered to complete the situational judgement test. The situational judgement test was developed to assess relevant professional attributes for dentistry (for example, empathy and integrity) in a machine-markable format. Test content was developed by subject matter experts working with experienced psychometricians. Evaluation of psychometric properties of the pilot situational judgement test (for example, reliability, validity and fairness). Scores in the dental foundation training selection process (short-listing and interviews) were used to examine criterion-related validity. Candidates completed an evaluation questionnaire to examine candidate reactions and face validity of the new test. Forty-six candidates were female and 28 male; mean age was 23.5-years-old (range 22-32). Situational judgement test scores were normally distributed and the test showed good internal reliability when corrected for test length (α = 0.74). Situational judgement test scores positively correlated with the management, leadership and professionalism interview (N = 50; r = 0.43, p fair. This initial pilot study suggests that a situational judgement test is an appropriate and innovative method to measure professional attributes (eg empathy and integrity) for selection into foundation training. Further research will explore the long-term predictive validity of the situational judgement test once candidates have entered training.

Study of filling material of dental composites. An analytical approach using radio-activation

Energy Technology Data Exchange (ETDEWEB)

Eke, Canel [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Akdeniz Univ., Antalya (Turkey). Div. of Physics Education; Er, Kursat [Akdeniz Univ., Antalya (Turkey). Dept. of Endodontics; Segebade, Christian [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Boztosun, Ismail [Akdeniz Univ., Antalya (Turkey). Nuclear Sciences Application and Research Center; Akdeniz Univ., Antalya (Turkey). Dept. of Physics

2018-04-01

The aim of this study is to carry out elemental analyses of dental composites acquired from different producers using photoactivation analysis (PAA). High energy electrons produced by an electron linear accelerator are absorbed by a tungsten disk (Bremsstrahlung converter) thereby producing high energy X-rays (bremsstrahlung). The dental composite materials under study were exposed to the bremsstrahlung radiation whereby radionuclides were produced through photonuclear reactions. Their radioactivities were measured using high resolution semiconductor spectrometers equipped with high purity germanium detectors (HPGe). The spectra were analysed using appropriate computer software. As a result, photonuclear reactions of 12 stable elements were detected in different dental composite species, and the elemental concentrations were calculated. For comparison, the dental composites were also investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray fluorescence spectrometry (EDXRF). Various sizes and shapes of dental composites were observed using SEM. However, contents of dental composites, e.g. Mg, Ni, Ba and Sr were obtained by PAA whilst C, O, Al, S, Ba and Sr were detected by EDXRF spectrometry. The results for Ba and Sr obtained using the two techniques show considerable difference.

About Dental Amalgam Fillings

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... and Medical Procedures Dental Devices Dental Amalgam About Dental Amalgam Fillings Share Tweet Linkedin Pin it More ... should I have my fillings removed? What is dental amalgam? Dental amalgam is a dental filling material ...

Readability of pediatric health materials for preventive dental care

Directory of Open Access Journals (Sweden)

Riedy Christine A

2006-11-01

Full Text Available Abstract Background This study examined the content and general readability of pediatric oral health education materials for parents of young children. Methods Twenty-seven pediatric oral health pamphlets or brochures from commercial, government, industry, and private nonprofit sources were analyzed for general readability ("usability" according to several parameters: readability, (Flesch-Kincaid grade level, Flesch Reading Ease, and SMOG grade level; thoroughness, (inclusion of topics important to young childrens' oral health; textual framework (frequency of complex phrases, use of pictures, diagrams, and bulleted text within materials; and terminology (frequency of difficult words and dental jargon. Results Readability of the written texts ranged from 2nd to 9th grade. The average Flesch-Kincaid grade level for government publications was equivalent to a grade 4 reading level (4.73, range, 2.4 – 6.6; F-K grade levels for commercial publications averaged 8.1 (range, 6.9 – 8.9; and industry published materials read at an average Flesch-Kincaid grade level of 7.4 (range, 4.7 – 9.3. SMOG readability analysis, based on a count of polysyllabic words, consistently rated materials 2 to 3 grade levels higher than did the Flesch-Kincaid analysis. Government sources were significantly lower compared to commercial and industry sources for Flesch-Kincaid grade level and SMOG readability analysis. Content analysis found materials from commercial and industry sources more complex than government-sponsored publications, whereas commercial sources were more thorough in coverage of pediatric oral health topics. Different materials frequently contained conflicting information. Conclusion Pediatric oral health care materials are readily available, yet their quality and readability vary widely. In general, government publications are more readable than their commercial and industry counterparts. The criteria for usability and results of the analyses

Does 6 Hours of Contact With Alginate Impression Material Affect Dental Cast Properties?

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Ibrahim, Amna Adam; Alhajj, Mohammed Nasser; Khalifa, Nadia; Gilada, Magdi Wadie

2017-06-01

Alginate impression (irreversible hydrocolloid) material is commonly used in dental practice because it is easy to mix, low in cost, and well tolerated by patients. The material is not dimensionally stable, however; thus, it is necessary to pour the impression immediately after the molding is accomplished, or within 60 minutes if the impression is kept in 100% humidity. Excessive contact of the alginate impression with the cast model over time may affect the model's properties. In this study, the authors tested the effect of contact time between an alginate impression and type III dental stone on cast model properties. Sixty-seven cast models were obtained from a stainless steel cylinder by using irreversible hydrocolloid impression material and type III dental stone. Thirty-seven cast models were separated from the impression after 1 hour (control group) and 30 cast models were separated after 6 hours (study group). The samples were evaluated under light microscope for surface details and measured by digital caliper for dimensional stability. An indentation on the cast was made and the depth of the indentation was then measured with a digital caliper to measure hardness. The dimensional stability of the cast models was not affected when contact time was increased from 1 hour to 6 hours (P = .507). Surface details did not deteriorate when contact time was increased, as all of the samples could reproduce all details after the 1-hour and 6-hour interval periods. However, hardness was greater after 1 hour of contact time (P = .001) than after 6 hours of contact time. In conclusion, contact between alginate impression material and type III dental stone up to 6 hours did not affect the dimensional stability and richness of the surface; hardness, though, was significantly affected.

Occupational exposure to contaminated biological material: perceptions and feelings experienced among dental students

Directory of Open Access Journals (Sweden)

Camila PINELLI

Full Text Available INTRODUCTION: Dental students may be a particularly vulnerable group exposed to the risk of acquiring infections through occupational injuries.OBJECTIVE: To investigate the perceptions with regard to their occupational exposure to potentially infectious biologic materials.MATERIAL AND METHOD: Interviews were conducted by means of a script with open questions. The speeches were recorded, transcribed and qualitative analysis was performed with the aid of QUALIQUANTISOFT® software. The Collective Subject Discourse (CSD was obtained.RESULT: The feeling most frequently experienced was related to the fear of contagion. Most accidents occurred during the handling of sharp dental instruments. Respondents attributed the occurrence of accidents especially the lack of attention, carelessness while handling sharp instruments, and lack of use of Personal Protective Equipment. As regards the measures taken right after the exposure, they "washed the local area". Other respondents reported they "continued the dental treatment". They complained mostly about the fear of having been infected, and because they had to leave the faculty to take blood exams for HIV screening. As part of the learning experience the injured reported they paid more attention when handling sharp instruments. The students informed that any type of injury due to contact with contaminated material must be notified. However, they were neglectful about reporting their own injury.CONCLUSION: Education strategies for preventive measures related to occupational exposure must be restructured, because the knowledge and the fear of contagion among dental students were not always sufficient for a complete adherence to treatment protocols and notification.

Mechanical characterization of materials for dental applications

International Nuclear Information System (INIS)

Pajares, A.; Miranda, P.; Guiberteau, F.; Cumbrera, F. I.

2001-01-01

An study of the damage induced in dental materials and model multilayer systems by masticatory contact stresses, simulated by hertz ian indentation test, have been performed. In particular, the nature of induced damage has been identified, and quantified from stress-strain curves and critical loads for yielding or crack initiation. For multilayer systems, test have been numerically simulated using finite element techniques (FEM). FEM simulations complement indentation test, allowing to justify the observed fracture modes from calculated stress fields. Practical implications can be derived from our results, relevant to the design of multilayer structures tolerant to contact damage. (Author) 34 refs

A survey of U.S. prosthodontists and dental schools on the current materials and methods for final impressions for complete denture prosthodontics.

Science.gov (United States)

Petrie, Cynthia S; Walker, Mary P; Williams, Karen

2005-12-01

The purpose of this study was to survey members of The American College of Prosthodontists (ACP) to evaluate current materials and methods for final impressions for complete denture prosthodontics in the United States. In addition, those methods were compared with methods and materials taught in U.S. dental schools via a second survey sent to the chairpersons of prosthodontic/restorative departments. An anonymous questionnaire was mailed to all 1762 active ACP members in the United States in 2003. A slightly modified questionnaire was also distributed to chairpersons of prosthodontic/restorative departments in the 54 U.S. dental schools. Data analysis was performed via frequency distribution and chi-square statistics. Nine hundred and forty-five questionnaires were returned by members of the ACP (54% return rate) and 42 questionnaires were returned by the U.S. dental schools (78% return rate). The majority of the reporting prosthodontists (88%) and dental schools (98%) use a border-molded custom tray for final impressions for complete denture prosthodontics. The most popular material for border molding was plastic modeling compound (67% of reporting ACP members, and 95% of the responding dental schools). Variability of the materials used for final impressions was observed, with the most popular materials being polyvinylsiloxane for the ACP members (36%) and polysulfide for the dental schools (64%). Statistically significant differences were found in the materials used for border molding by prosthodontists based on the time elapsed since completion of prosthodontic training. No differences were found in the materials used for impression of edentulous arches based on years of experience. Geographic location did not influence the materials and methods used by prosthodontists for complete denture final impressions. There was variability of the materials and techniques used for final impressions by ACP members and dental schools; however, overall there was an agreement

Study of the luminescence properties of dental materials for their use in accidental dosimetry

International Nuclear Information System (INIS)

Veronese, Ivan; Cantone, Marie C.; Guzzi, Gianpaolo

2008-01-01

Full text: The current social and political situation in many world areas and the increasing hostilities between countries and cultures have accentuated the risk of a malicious use of ionising radiations. Terrorist attacks with the intentional disseminations of radioactive materials in urban settlements may involve a large number of persons, and a rapid estimation of the severity of the exposure is required for undertaking suitable protective actions and supporting decision making. Promising methodologies for a prompt dose evaluation, are those exploiting the luminescence and dosimetric properties of objects and materials which can be easily found in the contaminated area. Among these objects, dental materials have the advantage to be on contact with human body and they could therefore represent individual dosimeters in case of accidental exposure to ionising radiation. The interest in the use of dental ceramics for dosimetric purposes dates back to late 1970, however, it is only through the use of high-sensitive experimental techniques and instrumentation today available, that the potentiality of such materials as accidental dosimeters can be exploited. Moreover, innovative materials are being continuously introduced into the market, containing new additives and pigments with peculiar optical properties. In this study, Thermally Stimulated Luminescence (TSL) and Optically Stimulated Luminescence (OSL) techniques are applied to investigate the luminescence and dosimetric properties of several dental materials, including resins, glass and feldspatic ceramics, and also zirconia and alumina based ceramics, being their use widely increased in the recent years in substitution of metal cores. (author)

Metallurgical and interfacial characterization of PFM Co-Cr dental alloys fabricated via casting, milling or selective laser melting.

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Al Jabbari, Y S; Koutsoukis, T; Barmpagadaki, X; Zinelis, S

2014-04-01

Bulk and interfacial characterization of porcelain fused to metal (PFM) Co-Cr dental alloys fabricated via conventional casting, milling and selective laser melting. Three groups of metallic specimens made of PFM Co-Cr dental alloys were prepared using casting (CST), milling (MIL) and selective laser sintering (SLM). The porosity of the groups was evaluated using X-ray scans. The microstructures of the specimens were evaluated via SEM examination, EDX and XRD analysis. Vickers hardness testing was utilized to measure the hardness of the specimens. Interfacial characterization was conducted on the porcelain-covered specimens from each group to test the elemental distribution with and without the application of INmetalbond. The elemental distribution of the probed elements was assessed using EDX line profile analysis. Hardness results were statistically analyzed using one-way ANOVA and Holm-Sidak's method (α=0.05). X-ray radiography revealed the presence of porosity only in the CST group. Different microstructures were identified among the groups. Together with the γ phase matrix, a second phase, believed to be the Co3Mo phase, was also observed by SEM and subsequent XRD analysis. Cr7C3 and Cr23C6 carbides were also identified via XRD analysis in the CST and MIL groups. The hardness values were 320±12 HV, 297±5 HV and 371±10 HV, and statistically significant differences were evident among the groups. The microstructure and hardness of PFM Co-Cr dental alloys are dependent on the manufacturing technique employed. Given the differences in microstructural and hardness properties among the tested groups, further differences in their clinical behavior are anticipated. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Hard tissue formation of STRO-1-selected rat dental pulp stem cells in vivo.

NARCIS (Netherlands)

Yang, X.; Walboomers, X.F.; Beucken, J.J.J.P van den; Bian, Z.; Fan, M.; Jansen, J.A.

2009-01-01

The objective of this study was to examine hard tissue formation of STRO-1-selected rat dental pulp-derived stem cells, seeded into a calcium phosphate ceramic scaffold, and implanted subcutaneously in mice. Previously, STRO-1 selection was used to obtain a mesenchymal stem cell progenitor

Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Merghni, Abderrahmen, E-mail: abderrahmen_merghni@yahoo.fr [Laboratoire des Maladies Transmissibles et Substances biologiquement actives (LR99ES27) Faculté de Pharmacie de Monastir, Université de Monastir (Tunisia); Kammoun, Dorra [Laboratoire de Biomatériaux et Biotechnologie, Faculté de Médecine Dentaire, Monastir (Tunisia); Hentati, Hajer [Laboratoire de Recherche en Santé Orale et Réhabilitation Bucco-Faciale (LR12ES11), Faculté de Médecine Dentaire de Monastir, Université de Monastir (Tunisia); Janel, Sébastien [BioImaging Center Lille-FR3642, Lille (France); Popoff, Michka [Cellular Microbiology and Physics of Infection-CNRS UMR8204, INSERM U1019, Institut Pasteur de Lille, Lille University (France); Lafont, Frank [BioImaging Center Lille-FR3642, Lille (France); Cellular Microbiology and Physics of Infection-CNRS UMR8204, INSERM U1019, Institut Pasteur de Lille, Lille University (France); Aouni, Mahjoub [Laboratoire des Maladies Transmissibles et Substances biologiquement actives (LR99ES27) Faculté de Pharmacie de Monastir, Université de Monastir (Tunisia); Mastouri, Maha [Laboratoire des Maladies Transmissibles et Substances biologiquement actives (LR99ES27) Faculté de Pharmacie de Monastir, Université de Monastir (Tunisia); Laboratoire de Microbiologie, CHU Fattouma Bourguiba de Monastir (Tunisia)

2016-08-30

Highlights: • 4 dental restorative materials were characterized for roughness, angle contact water and surface free energy. • AFM adhesion forces of S. aureus to tested materials were achieved in presence and absence of salivary conditioning film. • S. aureus initial adhesion is dependent on the surface free energy and roughness. - Abstract: In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

International Nuclear Information System (INIS)

Merghni, Abderrahmen; Kammoun, Dorra; Hentati, Hajer; Janel, Sébastien; Popoff, Michka; Lafont, Frank; Aouni, Mahjoub; Mastouri, Maha

2016-01-01

Highlights: • 4 dental restorative materials were characterized for roughness, angle contact water and surface free energy. • AFM adhesion forces of S. aureus to tested materials were achieved in presence and absence of salivary conditioning film. • S. aureus initial adhesion is dependent on the surface free energy and roughness. - Abstract: In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

Moldable setting time evaluation between sodium alginate and bovine gelatine of glutinous rice mixture as dental putty materials

Science.gov (United States)

Takarini, V.; Hasratiningsih, Z.; Karlina, E.; Febrida, R.; Asri, L. A. T. W.; Purwasasmita, BS

2017-02-01

Putty elastomeric material is a viscous, moldable material that can be used as a dental impression to record and duplicate the tooth structure. Commercially available putty materials are hardly found in the Indonesian market. The aim of this work is to develop an alternative putty dental material from glutinous rice with two different gelling agents; sodium alginate and bovine gelatine. A commercially putty material was used as a control. The length of time required for the putty materials to set (setting time) was evaluated with compression set test. The result showed that sodium alginate and bovine gelatine gelling agents resulted in moldable putty materials that comparable to the commercial product. Glutinous rice mixed with sodium alginate gelling agent demonstrated longer setting time (more than 1 hours) compared to bovine gelatine (6 minutes). These may occur due to heat treatment applied to the bovine gelatine, while sodium alginate mixture has a chemical reaction since CaCl2 crosslink agent had been added to the mixture. Glutinous rice with bovine gelatine mixture is a promising candidate to be used as a dental putty material.

Materials selection in mechanical design

International Nuclear Information System (INIS)

Ashby, M.F.; Cebon, D.

1993-01-01

A novel materials-selection procedure has been developed and implemented in software. The procedure makes use of Materials Selection Charts: a new way of displaying material property data; and performance indices: combinations of material properties which govern performance. Optimisation methods are employed for simultaneous selection of both material and shape. (orig.)

Materials selection in mechanical design

OpenAIRE

Ashby , M.; Cebon , D.

1993-01-01

A novel materials-selection procedure has been developed and implemented in software. The procedure makes use of Materials Selection Charts: a new way of displaying material property data; and performance indices: combinations of material properties which govern performance. Optimisation methods are employed for simultaneous selection of both material and shape.

Micro energy-dispersive X-ray fluoresence mapping of enamel and dental materials after chemical erosion.

Science.gov (United States)

Soares, Luís Eduardo Silva; de Oliveira, Rodrigo; Nahórny, Sídnei; Santo, Ana Maria do Espírito; Martin, Airton Abrahão

2012-10-01

Energy-dispersive X-ray fluorescence was employed to test the hypothesis that beverage consumption or mouthwash utilization will change the chemical properties of dental materials and enamel mineral content. Bovine enamel samples (n = 45) each received two cavity preparations (n = 90), each pair filled with one of three dental materials (R: nanofilled composite resin; GIC: glass-ionomer cement; RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: saliva; E: erosion/Pepsi Twist®; or EM: erosion+mouthwash/Colgate Plax®). It was found that mineral loss in enamel was greater in GICE samples than in RE > RMGICE > RMGICEM > REM > GICEM. An increased percentage of Zr was found in REM indicating organic matrix degradation. Dental materials tested (R, GIC, and RMGIC) were not able to protect adjacent enamel from acid erosion by the soft drink tested. The use of mouthwash promoted protection of enamel after erosion by the soft drink. To avoid chemical dissolution by mouthwashes, protection by resin composites with surface sealants is recommended.

Prevalence and distribution of selected developmental dental anomalies in an Indian population.

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Gupta, Saurabh K; Saxena, Payal; Jain, Sandhya; Jain, Deshraj

2011-06-01

The purpose of this study was to determine the prevalence of developmental dental anomalies in an Indian population and to statistically analyze the distribution of these anomalies. The study was based on clinical examination, evaluation of dental casts, and panoramic radiographs of 1123 Indian subjects (572 males, 551 females), who visited the outpatient clinic at Government Dental College, Indore between November 2009 and September 2010, after obtaining their informed consent. These patients were examined for the following developmental dental anomalies: shape anomalies (microdontia, talon cusp, dens evaginatus, fusion, taurodontism), number anomalies (hypodontia, oligodontia, anodontia), structural anomalies (amelogenesis imperfecta, dentinogenesis imperfecta) and positional anomalies (ectopic eruption, rotation, impaction). The percentages of these anomalies were assessed for the whole group and compared using statistical analysis. Among the 1123 subjects, a total of 385 individuals (34.28%) presented with the selected developmental dental anomalies. The distribution by sex was 197 males (34.44%), and 188 females (34.06%). Out of the total 1123 individuals, 351 (31.26%) exhibited at least one anomaly, 28 (2.49 %) showed two anomalies and 6 (0.53%) displayed more than two anomalies. P values indicated that the dental anomalies were statistically independent of sex. On intergroup comparison, positional anomalies were significantly most prevalent (P dental anomaly was rotation (10.24%), followed by ectopic eruption (7.93%). The next common group was number anomalies. The most common number anomaly was hypodontia (4.19%), which had a higher frequency than hyperdontia (2.40%). Analyzing the next prevalent group of shape anomalies, microdontia (2.58%) was found to be the most common, followed by taurodontism (2.49%), dens evaginatus (2.40%) and talon cusp (0.97%). Dentinogenesis imperfecta (0.09%) was the rarest, followed by amelogenesis imperfecta (0.27%) and fusion

Knowledge and attitude towards preventive dental care among dental faculties in Bangalore city

Directory of Open Access Journals (Sweden)

Nikhil Ahuja

2014-01-01

Full Text Available Background and Objectives: Preventive approach in dental practice has been cited as a reason for the decline in oral diseases and as a predominant part of the service-mix of dental practices in the future. Dental faculty′s knowledge and attitude toward prevention are important, since they have exceptionally important direct and indirect roles in shaping student′s preventive orientation and also potentially influencing their patient′s ability to take care of their teeth. Thus, this study was conducted to assess knowledge and attitudes toward preventive dental care among dental faculties and their relation to demographic and professional characteristics. Materials and Methods: A cross-sectional study was conducted among dental faculties in Bangalore city. Of 17 dental colleges, 4 were selected by simple random sampling. A total of 218 dental faculties was individually asked to complete a pretested questionnaire. The questionnaire requested information on dental faculty′s demographic and professional characteristics and their knowledge and attitudes toward preventive dental care. Descriptive, Chi-square tests, and ANOVA were used to analyze the data. Results: The highest knowledge was seen among dental faculties regarding prevention of malocclusion (3.51 ± 1.02 followed by oral cancer (2.95 ± 1.09 and periodontal diseases (2.86 ± 1.02. The least knowledge was seen for the prevention of caries (2.63 ± 1.35. The most positive attitudes regarding preventive dentistry was characterized as being essential (6.34 ± 1.05, useful (6.32 ± 1.07 and valuable (6.27 ± 1.00. Statistically significant differences were found in relation to knowledge and attitudes for all demographic and professional characteristics except for gender and Department of Teaching. Conclusion: Dental faculty seems to have differing levels of knowledge regarding oral diseases with positive attitudes seen regarding preventive dentistry. Continuing education activities and

Morphological characterization of ceramic fillers made from Indonesian natural sand as restorative dental materials

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Karlina, E.; Susra, S.; Fatmala, Y.; Hartoyo, H. M.; Takarini, V.; Usri, K.; Febrida, R.; Djustiana, N.; Panatarani, C.; Joni, I. M.

2018-02-01

Dental composite as restorative dental materials can be reinforced using ceramic fillers. Homogeneous distribution of filler particles shall improve its mechanical properties. This paper presents the results of the preliminary study on the ZrO2-Al2O3-SiO2 ceramic fillers made from Indonesian natural sand that can increase the mechanical properties of dental composite. The synthesis was done using zirconium silicate sand (ZrSiO4) and aluminium oxide (Al2O3) precursors, which dissolved together with 70:30 weight ratios. Two types of sand were used: (1) manufactured sand (mesh #80) and (2) natural sand (mesh #400). The samples then heated in the furnace at 1100 °C for 8 hours. The morphological characterization was then evaluated using JEOL Scanning Electron Microscope (SEM) for the surface structure that analyze particles size and distribution. Ceramic fillers made from natural sand is homogenous, well distributed with average particle size of 5-10 µm. Comparably, ceramic filler made from the manufactured sand is heterogeneous, poorly distributed and appear as agglomerates with average particle size are 30-50 µm. The results suggest that ceramic fillers made from natural sand demonstrate better character to represent as a functional restorative dental material.

Evaluation of accuracy of multiple dental implant impressions using various splinting materials.

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Hariharan, Rasasubramanian; Shankar, Chitra; Rajan, Manoj; Baig, Mirza Rustum; Azhagarasan, N S

2010-01-01

The aim of the present study was to compare the accuracy of casts obtained from nonsplinted and splinted direct impression techniques employing various splinting materials for multiple dental implants. A reference model with four Nobel Replace Select implant replicas in the anterior mandible was fabricated with denture base heat-curing acrylic resin. Impressions of the reference model were made using polyether impression material by direct nonsplinted and splinted techniques. Impressions were divided into four groups: group A: nonsplinted technique; group B: acrylic resin-splinted technique; group C: bite registration addition silicone-splinted technique; and group D: bite registration polyether-splinted technique. Four impressions were made for each group and casts were poured in type IV dental stone. Linear differences in interimplant distances in the x-, y-, and z-axes and differences in interimplant angulations in the z-axis were measured on the casts using a coordinate measuring machine. The interimplant distance D1y showed significant variations in all four test groups (P = .043), while D3x values varied significantly between the acrylic resin-splinted and silicone-splinted groups. Casts obtained from the polyether-splinted group were the closest to the reference model in the x- and y-axes. In the z-axis, D2z values varied significantly among the three test groups (P = .009). Casts from the acrylic resin-splinted group were the closest to the reference model in the z-axis. Also, one of the three angles measured (angle 2) showed significant differences within three test groups (P = .009). Casts from the nonsplinted group exhibited the smallest angular differences. Casts obtained from all four impression techniques exhibited differences from the reference model. Casts obtained using the bite registration polyether-splinted technique were the most accurate versus the reference model, followed by those obtained via the acrylic resin-splinted, nonsplinted, and

Dental records of forensic odontological importance: Maintenance pattern among dental practitioners of Pune city

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Sarode, Gargi S; Sarode, Sachin C; Choudhary, Shakira; Patil, Shankargouda; Anand, Rahul; Vyas, Himadri

2017-01-01

Context: Forensic odontology plays a pivotal role in the identification of victims in mass disasters with the help of “Preserved dental records” available with the general dental practitioners (GDPs). However, the status of such dental records of forensic importance has not been studied extensively. Aim: To study the current status of awareness and practice of dental record maintenance by GDPs of Pune. Materials and Methods: A cross-sectional study was conducted among 100 randomly selected GDPs from Pune. Data was collected in a personalized manner by means of a questionnaire. Results: Six percent of GDPs do not maintain any records of the patient, 11% of them do not record about developmental dental anomalies, and 22% GDPs do not retain radiographs. Sixty-seven percent GDPs mention about the use of abbreviations while recording history. Only 17% of GDPs record denture marking and 11% take conformity certificate for the denture. Thirty percent GDPs do not mention the serial number of an implant whereas 17% of them do not mention about the prescribed medication. Five percent GDPs handover original dental record to the patient and 91% said that they discard casts and models immediately after treatment. Conclusion: There was inadequate knowledge and lack of practice regarding proper record maintenance among GDPs. PMID:28584484

Evaluation of dental solid waste in Hamedan

Directory of Open Access Journals (Sweden)

Nabizadeh R.

2009-08-01

Full Text Available "nBackground and Aim: Today, one of the most important environmental issues is dental solid wastes which are of great importance because of the presence of hazardous, toxic and pathogen agents. In this survey, solid waste produced in Hamedan general dental offices is evaluated. "nMaterials and Methods: In this descriptive study, from 104 general dental offices in Hamedan , 10 offices were selected in simple random way. From each offices, 3 sample at the end of successive working day (Sunday, Monday and Tuesday were analyzed. Samples were manually sorted into different 74 components and measured by means of laboratory scale. Then, measured components were classified in the basis of characteristic and hazardous potential as well as material type. "nResults: Total annual waste produced in general dental offices in Hamadan is 14662.67 Kg (9315.45>95.0% Confidence Interval>20009.88. Production percentages of infectious, domestic type, chemical and pharmaceutical and toxic wastes were 51.93, 38.16, 9.47, 0.44 respectively. Main components of produced dental waste were 14 components that consist of more than 80 percents of total dental solid waste. So, waste reduction, separation and recycling plans in the offices must be concentrated on these main components. "nConclusion: In order to dental waste proper management, it is suggested that in addition to educate dentists for waste reduction, separation and recycling in the offices, each section of dental waste(toxic,chemical and pharmaceutical, infectious and domestic type wastes separately and according to related criteria should be managed.

Magnetic susceptibility and electrical conductivity of metallic dental materials and their impact on MR imaging artifacts

Czech Academy of Sciences Publication Activity Database

Starčuková, Jana; Starčuk jr., Zenon; Hubálková, H.; Linetskiy, I.

2008-01-01

Roč. 24, č. 6 (2008), s. 715-723 ISSN 0109-5641 R&D Projects: GA MZd NR8110 Institutional research plan: CEZ:AV0Z20650511 Keywords : metallic dental materials * dental alloys * amalgams * MR imaging * magnetic susceptibility * electric conductivity * image artifact Subject RIV: FF - HEENT, Dentistry Impact factor: 2.941, year: 2008

Biocompatibility of dental alloys

Energy Technology Data Exchange (ETDEWEB)

Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

2001-10-01

Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

Students' perceptions of materials and techniques used at European dental schools in the education of fixed prosthodontics

NARCIS (Netherlands)

Brand, H.S.; Kamell, H.; Kharbanda, A.; Dozic, A.

2013-01-01

The aim of this study was to explore the materials and procedures used by students in dental schools across Europe for teaching fixed prosthodontics. An online questionnaire, containing twenty-eight dichotomous, multiple-choice, and Likert scale rating questions, was sent to students in forty dental

Characterization of Human Dental Pulp Tissue Under Oscillatory Shear and Compression.

Science.gov (United States)

Ozcan, Burak; Bayrak, Ece; Erisken, Cevat

2016-06-01

Availability of material as well as biological properties of native tissues is critical for biomaterial design and synthesis for regenerative engineering. Until recently, selection of biomaterials and biomolecule carriers for dental pulp regeneration has been done randomly or based on experience mainly due to the absence of benchmark data for dental pulp tissue. This study, for the first time, characterizes the linear viscoelastic material functions and compressive properties of human dental pulp tissue harvested from wisdom teeth, under oscillatory shear and compression. The results revealed a gel-like behavior of the pulp tissue over the frequency range of 0.1-100 rps. Uniaxial compression tests generated peak normal stress and compressive modulus values of 39.1 ± 20.4 kPa and 5.5 ± 2.8 kPa, respectively. Taken collectively, the linear viscoelastic and uniaxial compressive properties of the human dental pulp tissue reported here should enable the better tailoring of biomaterials or biomolecule carriers to be employed in dental pulp regeneration.

Dental Calculus Arrest of Dental Caries

Science.gov (United States)

Keyes, Paul H.; Rams, Thomas E.

2016-01-01

Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

In vitro biocompatibility of CoCrMo dental alloys fabricated by selective laser melting.

Science.gov (United States)

Hedberg, Yolanda S; Qian, Bin; Shen, Zhijian; Virtanen, Sannakaisa; Wallinder, Inger Odnevall

2014-05-01

Selective laser melting (SLM) is increasingly used for the fabrication of customized dental components made of metal alloys such as CoCrMo. The main aim of the present study is to elucidate the influence of the non-equilibrium microstructure obtained by SLM on corrosion susceptibility and extent of metal release (measure of biocompatibility). A multi-analytical approach has been employed by combining microscopic and bulk compositional tools with electrochemical techniques and chemical analyses of metals in biologically relevant fluids for three differently SLM fabricated CoCrMo alloys and one cast CoCrMo alloy used for comparison. Rapid cooling and strong temperature gradients during laser melting resulted in the formation of a fine cellular structure with cell boundaries enriched in Mo (Co depleted), and suppression of carbide precipitation and formation of a martensitic ɛ (hcp) phase at the surface. These features were shown to decrease the corrosion and metal release susceptibility of the SLM alloys compared with the cast alloy. Unique textures formed in the pattern of the melting pools of the three different laser melted CoCrMo alloys predominantly explain observed small, though significant, differences. The susceptibility for corrosion and metal release increased with an increased number (area) of laser melt pool boundaries. This study shows that integrative and interdisciplinary studies of microstructural characteristics, corrosion, and metal release are essential to assess and consider during the design and fabrication of CoCrMo dental components of optimal biocompatibility. The reason is that the extent of metal release from CoCrMo is dependent on fabrication procedures. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Competitive light absorbers in photoactive dental resin-based materials.

Science.gov (United States)

Hadis, Mohammed A; Shortall, Adrian C; Palin, William M

2012-08-01

The absorbance profile of photoinitiators prior to, during and following polymerization of light curable resin-based materials will have a significant effect on the cure and color properties of the final material. So-called "colorless" photoinitiators are used in some light-activated resin-based composite restorative materials to lessen the yellowing effect of camphoroquinone (CQ) in order to improve the esthetic quality of dental restorations. This work characterizes absorption properties of commonly used photoinitiators, an acylphosphine oxide (TPO) and CQ, and assesses their influence on material discoloration. Dimethacrylate resin formulations contained low (0.0134 mol/dm(3)), intermediate (0.0405 mol/dm(3)) or high (0.0678 mol/dm(3)) concentrations of the photoinitiators and the inhibitor, butylated hydroxytoluene (BHT) at 0, 0.1 or 0.2% by mass. Disc shaped specimens (n = 3) of each resin were polymerized for 60s using a halogen light curing unit. Dynamic measurements of photoinitiator absorption, polymer conversion and reaction temperature were performed. A spectrophotometer was used to measure the color change before and after cure. GLM three-way analysis of variance revealed significant differences (pphotoinitiator type (df = 1; F = 176.12)>% BHT (df = 2, F = 13.17). BHT concentration affected the rate of polymerization and produced lower conversion in some of the CQ-based resins. Significant differences between photoinitiator type and concentrations were seen in color (where TPO resins became yellower and camphoroquinone resins became less yellow upon irradiation). Reaction temperature, kinetics and conversion also differed significantly for both initiators (presins producing a visually perceptible color change upon polymerization, the color change was significantly less than that produced with CQ-based resins. Although some photoinitiators such as TPO may be a more esthetic alternative to CQ, they may actually cause significant color contamination when

Synthesis, characterization and antibacterial activity of copper, nickel and bimetallic Cu–Ni nanoparticles for potential use in dental materials

Directory of Open Access Journals (Sweden)

Liliana Argueta-Figueroa

2014-08-01

Full Text Available The antibacterial effect is a desirable property in dental materials. Development of simple methods for the preparation of nanosized metal particles has attracted significant attention because of their future applications due to unusual size-dependent antibacterial properties. Copper (Cu, Nickel (Ni and bimetallic Cu–Ni nanoparticles were prepared by a simple chemical method and their antibacterial activity was tested against the widely used standard human pathogens Staphylococcus aureus (gram-negative and Escherichia coli (gram-positive. Additionally, these nanoparticles were tested against the dental pathogen Streptococcus mutans. Our results are promising for potential use in dental materials science.

Hand hygiene amongst dental professionals in a tertiary dental clinic ...

African Journals Online (AJOL)

Objective: To evaluate hand washing attitude and practices among Dentists and Dental Students treating patients in a Nigerian Tertiary Dental Clinic. Materials and Methods: A cross-sectional survey of Dentists and Dental Students treating patients in University of Benin Teaching Hospital was conducted between February ...

Influence of dental filling material type on the concentration of interleukin 9 in the samples of gingival crevicular fluid

Directory of Open Access Journals (Sweden)

Stefanović Vladimir

2016-01-01

Full Text Available Background/Aim. Several cytokines and lymphokines (IL1β, ENA78, IL6, TNFα, IL8 and S100A8 are expressed during dental pulp inflammation. Analysis of gingival crevicu-lar fluid (GCF offers a non-invasive means of studying gen-eral host response in oral cavity. Although GCF levels of various mediators could reflect the state of inflammation both in dental pulp and gingiva adjacent to a tooth, GCF samples of those without significant gingivitis could be inter-preted as reflection of pulpal process. The aim of this study was to investigate IL9 GCF values in patients with dental car-ies and to assess possible influence of various dental fillings materials on local IL9 production. Methods. The study group included 90 patients, aged 18–70, with inclusion and exclusion criteria in the prospective clinical study. Of the 6 types of material used for the restoration of prepared cavities, 3 were intended for temporary and 3 for definitive restora-tion. According to dental fillings weight, all the participants were divided into 3 groups: those with fillings lighter than 0.50 g, those with 0.50–1.00 g, and those with fillings heavier than 1.00 g. Samples were taken from gingival sulcus using the filter paper technique. Clinical parameters were deter-mined by bleeding index, plaque index (Silness-Lou, 0–3, gingival index (0–3, and gingival sulcus depth. Cytokine con-centrations were assessed using commercially available cy-tomix. Results. According to the weight of dental fillings, there was a clear decreament trend of IL9 values meaning that dental defects greater than 1.00 g of dental filling were associated with lower GCF IL9 concentration. The IL9 val-ues correlated with the degree of gingival index and depth of gingival sulcus, being higher with more advanced gingivitis and more pronounced anatomical changes in the tooth edge. Different filling materials exerted various local IL9 responses. Zink polycarbonate cement and amalgam fillings induced

Radiation-induced dental caries, prevention and treatment - A systematic review.

Science.gov (United States)

Gupta, Nishtha; Pal, Manoj; Rawat, Sheh; Grewal, Mandeep S; Garg, Himani; Chauhan, Deepika; Ahlawat, Parveen; Tandon, Sarthak; Khurana, Ruparna; Pahuja, Anjali K; Mayank, Mayur; Devnani, Bharti

2015-01-01

Treatment of head and neck cancers (HNCs) involves radiotherapy. Patients undergoing radiotherapy for HNCs are prone to dental complications. Radiotherapy to the head and neck region causes xerostomia and salivary gland dysfunction which dramatically increases the risk of dental caries and its sequelae. Radiation therapy (RT) also affects the dental hard tissues increasing their susceptibility to demineralization following RT. Postradiation caries is a rapidly progressing and highly destructive type of dental caries. Radiation-related caries and other dental hard tissue changes can appear within the first 3 months following RT. Hence, every effort should be focused on prevention to manage patients with severe caries. This can be accomplished through good preoperative dental treatment, frequent dental evaluation and treatment after RT (with the exception of extractions), and consistent home care that includes self-applied fluoride. Restorative management of radiation caries can be challenging. The restorative dentist must consider the altered dental substrate and a hostile oral environment when selecting restorative materials. Radiation-induced changes in enamel and dentine may compromise bonding of adhesive materials. Consequently, glass ionomer cements have proved to be a better alternative to composite resins in irradiated patients. Counseling of patients before and after radiotherapy can be done to make them aware of the complications of radiotherapy and thus can help in preventing them.

MIND--a five-state regional approach to continuing dental education.

Science.gov (United States)

Watkins, F

1975-08-01

MIND has finished two years of operation as a regional center for continuing dental education. The responses from viewing cards, and the number of credit hours given, indicate that approximately 20% of the potential audience participated in the course offerings. Previous experience from a two-year study in South Dakota has shown that there are three major factors that are essential for effective use of television as a dissemination medium. These are as follows: 1) the program should establish effective use of the communication system to maintain an audience; 2) the quality of thr programming material that is televised must be high; 3) the program should be televised on a regular basis to develop viewer habits or expectations. With a potential audience of 11,000 persons, MIND has had to depend heavily on a bulk-rate mailing system to communicate with members of the dental profession. This has caused problems such as reminders not being received on time, or being lost in the mail, or not being read, so that the individual is unaware that the courses are being telecast. Another problem of mailing system is maintaining an up-to-date list of addresses. The names and addresses of the dental assistants are impossible to keep up to date. We use the lists of licensed dentists and dental hygienists issued each July and a list of the certified dental assistants, which, of course, does not include all the dental assistants in our five-state area. A system providing more direct contact with the individual needs to be developed. Quality of televised courses is determined by the clinician's style of presentation as well as by the content and organization of the course material. The selection of dental information aimed toward the dentist in general practice results in loss of some members of the viewing audience, particularly specialists and generalpractitioners who have confined their practice to a particular area of dentistry. Quality is also judged by the technical aspects

An in vitro study of dental enamel wear by restorative materials using radiometric method; Estudo in vitro do desgaste do esmalte dental pelos materiais restauradores utilizando metodo radiometrico

Energy Technology Data Exchange (ETDEWEB)

Adachi, Lena Katekawa

2000-07-01

There is an increasing demand and interest to study the dental materials wear as well as about the abrasion effect on antagonistic teeth. Due to the fact that the existent restorative materials have no specifications about their abrasiveness, it is necessary the establishment of degrees of comparison among them to support clinical application. In this work, the radiometric method was applied to study the enamel wear caused by another enamel and by restorative materials (Ceramco II, Noritake and Finesse porcelains, Artglass and Targis). The dental enamel made radioactive by irradiation at the IEA-R1m nuclear research reactor under a thermal neutron flux was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with this radioactive enamel. The enamel wear was evaluated by measuring beta activity of {sup 32}P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another enamel or by resin materials. Resin materials caused less enamel wear than another enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. This study allowed to conclude that the radiometric method proposed can be used satisfactorily in the evaluation of enamel wear by restorative materials. This method presents advantages due to quick responses and ease of analyses There is (author)

Materials Selection for Aerospace Systems

Science.gov (United States)

Arnold, Steven M.; Cebon, David; Ashby, Mike

2012-01-01

A systematic design-oriented, five-step approach to material selection is described: 1) establishing design requirements, 2) material screening, 3) ranking, 4) researching specific candidates and 5) applying specific cultural constraints to the selection process. At the core of this approach is the definition performance indices (i.e., particular combinations of material properties that embody the performance of a given component) in conjunction with material property charts. These material selection charts, which plot one property against another, are introduced and shown to provide a powerful graphical environment wherein one can apply and analyze quantitative selection criteria, such as those captured in performance indices, and make trade-offs between conflicting objectives. Finding a material with a high value of these indices maximizes the performance of the component. Two specific examples pertaining to aerospace (engine blades and pressure vessels) are examined, both at room temperature and elevated temperature (where time-dependent effects are important) to demonstrate the methodology. The discussion then turns to engineered/hybrid materials and how these can be effectively tailored to fill in holes in the material property space, so as to enable innovation and increases in performance as compared to monolithic materials. Finally, a brief discussion is presented on managing the data needed for materials selection, including collection, analysis, deployment, and maintenance issues.

An in vitro investigation of human enamel wear by restorative dental materials

International Nuclear Information System (INIS)

Adachi, L.K.; Saiki, M.; De Campos, T.N.

2001-01-01

A radiometric method was applied to asses enamel wear by another enamel and by restorative materials. The radioactive enamel was submitted to wear in a machine which allows sliding motion of an antagonistic surface in contact with the radioactive enamel. The enamel wear was evaluated by measuring the beta-activity of 32 P transferred to water from this irradiated tooth. Results obtained indicated that dental porcelains cause pronounced enamel wear when compared with that provoked by another natural enamel or by resin materials. Resin materials caused less enamel wear than another natural enamel. Vickers microhardness data obtained for antagonistic materials showed a correlation with the wear caused to the enamel. (author)

A novel laser-based method for controlled crystallization in dental prosthesis materials

Science.gov (United States)

Cam, Peter; Neuenschwander, Beat; Schwaller, Patrick; Köhli, Benjamin; Lüscher, Beat; Senn, Florian; Kounga, Alain; Appert, Christoph

2015-02-01

Glass-ceramic materials are increasingly becoming the material of choice in the field of dental prosthetics, as they can feature both high strength and very good aesthetics. It is believed that their color, microstructure and mechanical properties can be tuned such as to achieve an optimal lifelike performance. In order to reach that ultimate perfection a controlled arrangement of amorphous and crystalline phases in the material is required. A phase transformation from amorphous to crystalline is achieved by a heat treatment at defined temperature levels. The traditional approach is to perform the heat treatment in a furnace. This, however, only allows a homogeneous degree of crystallization over the whole volume of the parent glass material. Here a novel approach using a local heat treatment by laser irradiation is presented. To investigate the potential of this approach the crystallization process of SiO2-Li2O-Al2O3-based glass has been studied with laser systems (pulsed and continuous wave) operating at different wavelengths. Our results show the feasibility of gradual and partial crystallization of the base material using continuous laser irradiation. A dental prosthesis machined from an amorphous glassy state can be effectively treated with laser irradiation and crystallized within a confined region of a few millimeters starting from the body surface. Very good aesthetics have been achieved. Preliminary investigation with pulsed nanosecond lasers of a few hundreds nanoseconds pulse width has enabled more refinement of crystallization and possibility to place start of phase change within the material bulk.

A review of nanostructured surfaces and materials for dental implants: surface coating, patterning and functionalization for improved performance.

Science.gov (United States)

Rasouli, Rahimeh; Barhoum, Ahmed; Uludag, Hasan

2018-05-10

The emerging field of nanostructured implants has enormous scope in the areas of medical science and dental implants. Surface nanofeatures provide significant potential solutions to medical problems by the introduction of better biomaterials, improved implant design, and surface engineering techniques such as coating, patterning, functionalization and molecular grafting at the nanoscale. This review is of an interdisciplinary nature, addressing the history and development of dental implants and the emerging area of nanotechnology in dental implants. After a brief introduction to nanotechnology in dental implants and the main classes of dental implants, an overview of different types of nanomaterials (i.e. metals, metal oxides, ceramics, polymers and hydrides) used in dental implant together with their unique properties, the influence of elemental compositions, and surface morphologies and possible applications are presented from a chemical point of view. In the core of this review, the dental implant materials, physical and chemical fabrication techniques and the role of nanotechnology in achieving ideal dental implants have been discussed. Finally, the critical parameters in dental implant design and available data on the current dental implant surfaces that use nanotopography in clinical dentistry have been discussed.

Effectiveness of school dental screening on stimulating dental attendance rates in Vikarabad town: A randomized controlled trial

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Gadde Praveen

2014-01-01

Full Text Available Background: The school dental screening program has been in existence from the beginning of 20 th century. Its value in encouraging attendance among school children is not fully established. Aim: The aim was to determine the effectiveness of school dental screening on stimulating dental attendance rates among school children in Vikarabad town. Objectives: (a To compare the dental attendance rates between 6-9 and 10-13 years old age groups, among male and female school children in Vikarabad town. (b To identify the type of dental treatment received by the school children. Materials and Methods: A randomized controlled trial was conducted among school children aged 6-13 years old from 16 schools that were randomly selected and divided into two groups. Eight schools had a dental screening program (study group = 300 children and had blanket referral cards and 8 schools that did not have the intervention (control group = 300. The dental attendance rates were determined after 3 months of follow-up period by evaluating the blanket referral cards for the study group and by an oral questionnaire for the control group. Results: The dental attendance rate was 27% for the study group and 18% for the control group which is statistically significant. The attendance rate was higher among 10-13 years of children both in test group and control groups. Among the children who visited the dentist, 53% in the control group and 69% from the test group got simple amalgam and glass ionomer cement restorations. Conclusion: The dental attendance rates were improved following school dental screening.

Prevalence of manufacturing defects in latex examination gloves used in selected dental practices in central Saudi Arabia.

Science.gov (United States)

Al-Swuailem, Abdullah S

2014-07-01

To assess the defect rates in latex examination gloves used in selected dental practices in Riyadh, Saudi Arabia. In this cross-sectional study, a total of 796 latex examination gloves were collected from 5 governmental hospitals and 5 private dental practices between April 2012 and May 2012. The gloves were assessed for presence of defects visually (VT) and using water inflation test (WIT). One and 2 sample t-tests were used to assess significant differences in defect rates among each latex brand, and between governmental hospitals and private dental practices. Defects in latex gloves were more likely to be identified using WIT compared with VT (20.2% versus 4.3%, p=0.000). Using WIT, examined latex gloves had a defect rate approximately 8 times the acceptable quality level of 2.5% (20.2%, p=0.000). Using WIT, gloves used in private dental practices had significantly higher defect rates compared with governmental dental clinics (25.6% versus 14.6%, p=0.006). Most latex examination gloves used in the sampled governmental dental clinics and private dental practices in Riyadh had significantly higher preexisting defect rates than acceptable standard levels.

Dental restorative materials from a work environmental perspective

OpenAIRE

Lönnroth, Emma-Christin

1999-01-01

The main occupational health hazard for dental personnel is muscle-skeletal problem, followed by symptoms caused by exposure to chemicals. Clinical dental work includes exposure to a number of products like soap, detergents, disinfectants, amalgam, mono- and oligomers, catalysts, inhibitors, solvents and adhesives. Some are chemically very active. The aims of this thesis have been to survey the occurrence of symptoms from skin, eyes and respiratory tract among dental personnel working in gene...

Ultrashort pulse laser processing of hard tissue, dental restoration materials, and biocompatibles

Science.gov (United States)

Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

2007-07-01

During the last few years, ultra-short laser pulses have proven their potential for application in medical tissue treatment in many ways. In hard tissue ablation, their aptitude for material ablation with negligible collateral damage provides many advantages. Especially teeth representing an anatomically and physiologically very special region with less blood circulation and lower healing rates than other tissues require most careful treatment. Hence, overheating of the pulp and induction of microcracks are some of the most problematic issues in dental preparation. Up till now it was shown by many authors that the application of picosecond or femtosecond pulses allows to perform ablation with very low damaging potential also fitting to the physiological requirements indicated. Beside the short interaction time with the irradiated matter, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of the required quality. One main reason for this can be seen in the fact that during scanning the time period between two subsequent pulses incident on the same spot is so much extended that no heat accumulation effects occur and each pulse can be treated as a first one with respect to its local impact. Extension of this advantageous technique to biocompatible materials, i.e. in this case dental restoration materials and titanium plasma-sprayed implants, is just a matter of consequence. Recently published results on composites fit well with earlier data on dental hard tissue. In case of plaque which has to be removed from implants, it turns out that removal of at least the calcified version is harder than tissue removal. Therefore, besides ultra-short lasers, also Diode and Neodymium lasers, in cw and pulsed modes, have been studied with respect to plaque removal and sterilization. The temperature increase during laser exposure has been experimentally evaluated in parallel.

Evaluation of effects of ionizing radiation on materials used in dental restorations

International Nuclear Information System (INIS)

Maio, Mireia Florencio

2009-01-01

This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were submitted to X-ray beams of 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. The sample were submitted to Geiger-Mueller detectors and the ionization chambers in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a Germanium detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

Dental Pulp Defence and Repair Mechanisms in Dental Caries.

Science.gov (United States)

Farges, Jean-Christophe; Alliot-Licht, Brigitte; Renard, Emmanuelle; Ducret, Maxime; Gaudin, Alexis; Smith, Anthony J; Cooper, Paul R

2015-01-01

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Dental Pulp Defence and Repair Mechanisms in Dental Caries

Directory of Open Access Journals (Sweden)

Jean-Christophe Farges

2015-01-01

Full Text Available Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Knowledge and Perceptions Regarding Nicotine Replacement Therapy among Dental Students in Karnataka

OpenAIRE

Ajagannanavar, Sunil Lingaraj; Alshahrani, Obaid Abdullah; Jhugroo, Chitra; Tashery, Hamed Mohammed; Mathews, Jacob; Chavan, Khechari

2015-01-01

Background: Organized dentistry has recognized the role of oral health professionals in discouraging tobacco use. Unexplored level of knowledge regarding the benefits and prescription of nicotine replacement therapy (NRT) have aroused interest among us which initiated us to assess the knowledge and perception of dental students toward NRT among various dental colleges in Karnataka, South India. Materials and Methods: A questionnaire survey was done among 16 selected colleges in Karnataka. It ...

Hydrogen peroxide bleaching induces changes in the physical properties of dental restorative materials: Effects of study protocols.

Science.gov (United States)

Yu, Hao; Zhang, Chang-Yuan; Wang, Yi-Ning; Cheng, Hui

2018-03-01

The purpose of this study was to evaluate the influence of study protocols on the effects of bleaching on the surface roughness, substance loss, flexural strength (FS), flexural modulus (FM), Weibull parameters, and color of 7 restorative materials. The test materials included 4 composite resins, 1 glass-ionomer cement, 1 dental ceramic, and 1 polyacid-modified composite. The specimens were randomly divided into 4 groups (n = 20) according to different study protocols: a bleaching group at 25°C (group 25B), a bleaching group at 37°C (group 37B), a control group at 25°C (group 25C), and a control group at 37°C (group 37C). The specimens in the bleaching group were treated with 40% hydrogen peroxide for 80 min at the respective environmental temperatures. The surface roughness, substance loss, FS, FM, and color of the specimens were measured before and after treatment. FS data were also subjected to Weibull analysis, which was used to estimate of the Weibull modulus (m) and the characteristic strength (σ 0 ). Surface roughness increased and significant color changes were observed for all tested specimens after bleaching treatment, except for the ceramic. After bleaching at 37°C, the polyacid-modified composite showed significantly reduced FS, FM, m, and σ 0 values in comparison to the control specimens stored at 37°C in whole saliva. Significant differences were also found between the 37B and 25B polyacid-modified composite groups in terms of surface roughness, FS, m, σ 0 , and color changes. Varying effects of bleaching on the physical properties of dental restorative materials were observed, and the influences of the study protocols on bleaching effects were found to be material-dependent. The influence of study protocols on the effects of bleaching on the surface roughness, flexural properties, and color of dental restorative materials are material-dependent and should be considered when evaluating the effects of bleaching on dental restorative

Materials selection for cutting tools

International Nuclear Information System (INIS)

Burkhis, Adel M.

2008-01-01

The selection of proper tool steel for a given application is a difficult task. So; the most important selection factors in choosing cutting tool materials are based on their tool material requirements, cutting tool design and service conditions which is mainly considered as functional requirements. The processability requirements concerns in heat treat ability of the material tool. The classification of these tool materials were discussed with their properties requirement and percent of alloying element which is added to give best properties with a little increase in cost that highly appear in comparison of the selection. The cutting tool materials were evaluated based on two cases; The first was in case of rough surface; the high speed steels is the best material and the other was the ceramic material is the highest performance in cutting of soft or high rate of metal removal. (author)

[The effects of topical fluoridation of Ketac Molar Aplicap glass-ionomer material on the growth of cariogenic bacteria contained in the dental plaque].

Science.gov (United States)

Płuciennik-Stronias, Małgorzata; Zarzycka, Beata; Bołtacz-Rzepkowska, Elzbieta

2013-01-01

Dental caries is a bacterial disease. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. Modern fluoride-containing restorative materials are capable of releasing fluoride to the environment. Fluoride can be also accumulated in glass-ionomer cements, thus an attempt was made to saturate these materials with fluoride. The aim of the study was to evaluate the effect of topical fluoridation of Ketac Molar Aplicap glass-ionomer cement on the growth of Lactobacillus spp. in the dental plaque. The study was carried out in 15 patients with good oral hygiene, in whom 35 fillings with conventional glass-ionomer material, Ketac Molar Aplicap, were performed. After 6 months, three-day dental plaque from these fillings was examined. Next, fluoride was rubbed on the glass-ionomer surface and the examination of three-day dental plaque was repeated. No statistically significant differences (p = 0.143) in the amounts of Lactobacillus spp. in the plaque collected prior to and after topical fluoridation were revealed. Fluoride rubbed in the conventional glass-ionomer cement, Ketac Molar Aplicap, did not affect the amount of Lactobacillus spp. in the dental plaque growing on this material.

Determining the complex modulus of alginate irreversible hydrocolloid dental material.

Science.gov (United States)

King, Shalinie; See, Howard; Thomas, Graham; Swain, Michael

2008-11-01

The aim of the study is to investigate the visco-elastic response of an alginate irreversible hydrocolloid dental impression material during setting. A novel squeeze film Micro-Fourier Rheometer (MFR, GBC Scientific Equipment, Australia) was used to determine the complex modulus of an alginate irreversible hydrocolloid dental impression material (Algident, ISO 1563 Class A Type 1, Dentalfarm Australia Pty. Ltd.) during setting after mixing. Data was collected every 30s for 10 min in one study and every 10 min for a total of 60 min in another study. A high level of repeatability was observed. The results indicate that the MFR is capable of recording the complex shear modulus of alginate irreversible hydrocolloid for 60 min from the start of mixing and to simultaneously report the changing visco-elastic parameters at all frequencies between 1 Hz and 100 Hz. The storage modulus shows a dramatic increase to 370% of its starting value after 6 min and then reduces to 55% after 60 min. The loss modulus increases to a maximum of 175% of its starting value after 10 min and then reduces to 94% after 60 min. The MFR enables the changes in the complex modulus through the complete setting process to be followed. It is anticipated this approach may provide a better method to compare the visco-elastic properties of impression materials and assist with identification of optimum types for different clinical requirements. The high stiffness of the instrument and the use of band-limited pseudo-random noise as the input signal are the main advantages of this technique over conventional rheometers for determining the changes in alginate visco-elasticity.

Selection criteria for dental radiography

International Nuclear Information System (INIS)

1998-01-01

The Faculty of General Dental Practitioners (UK) has a declared commitment to 'improving the standards of patient care'. By the provision of standards and guidelines it aims to help the profession to achieve this goal. Standards and guidelines are simply tools a dentist may use to improve treatment planning and care outcomes. The Self-Assessment Manual and Standards, SAMS, first published in 1991, is now well known to the profession and has become a frequently quoted source in clinical audit and quality assurance initiatives. Since its publication the scientific methodology of systematic reviews of the literature has progressed dramatically and this book is based on these developments. Evidence-based care is well established in medicine and dentistry and these selection criteria and guidelines follow these established protocols by basing advice on the available scientific evidence wherever possible. This book's purpose is a practical one, it is not intended to be limiting or restrictive but to be useful in the decision-making process. This is the first in a series of standards documents from the FGDP(UK) which are based on reviews of the scientific literature and employ the Scottish Intercollegiate Guideline Network (SIGN) methodology for guideline production. They are not constraints but an aid to effective treatment planning and patient care

Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

Directory of Open Access Journals (Sweden)

Ning Zhang

2016-11-01

Full Text Available A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1 develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2 investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC; the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU, and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1, and much greater than RMGI (p < 0.05. Composite with 3% MPC had protein adsorption that was only 1/10 that of control composites (p < 0.05. Composite with 3% MPC had biofilm CFU and lactic acid much lower than control composites (p < 0.05. Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI (p > 0.1. In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

The importance of dental aesthetics among dental students assessment of knowledge

OpenAIRE

Manipal, Sunayana; Mohan, C. S. Anand; Kumar, D. Lokesh; Cholan, Priyanka K.; Ahmed, Adil; Adusumilli, Preethi

2014-01-01

Objective: The aim of this study is to assess the dental esthetics awareness among dental students in a private university in Chennai as none is available in Chennai, Tamil Nadu. Materials and Methods: The dental esthetics awareness questionnaire consisting of a battery of 19 questions under five aspects that is, physical, functional, social, knowledge, and psychological aspects was administered to a sample of 100 dental college students aged between 18 and 27 years in a private college in Ch...

Reduction of metal artifact in three-dimensional computed tomography (3D CT) with dental impression materials.

Science.gov (United States)

Park, W S; Kim, K D; Shin, H K; Lee, S H

2007-01-01

Metal Artifact still remains one of the main drawbacks in craniofacial Three-Dimensional Computed Tomography (3D CT). In this study, we tried to test the efficacy of additional silicone dental impression materials as a "tooth shield" for the reduction of metal artifact caused by metal restorations and orthodontic appliances. 6 phantoms with 4 teeth were prepared for this in vitro study. Orthodontic bracket, bands and amalgam restorations were placed in each tooth to reproduce various intraoral conditions. Standardized silicone shields were fabricated and placed around the teeth. CT image acquisition was performed with and without silicone shields. Maximum value, mean, and standard deviation of Hounsfield Units (HU) were compared with the presence of silicone shields. In every situation, metal artifacts were reduced in quality and quantity when silicone shields are used. Amalgam restoration made most serious metal artifact. Silicone shields made by dental impression material might be effective way to reduce the metal artifact caused by dental restoration and orthodontic appliances. This will help more excellent 3D image from 3D CT in craniofacial area.

A rare allergy to a polyether dental impression material.

Science.gov (United States)

Mittermüller, Pauline; Szeimies, Rolf-Markus; Landthaler, Michael; Schmalz, Gottfried

2012-08-01

Polyether impression materials have been used in dentistry for more than 40 years. Allergic reactions to these materials such as reported in the 1970s ceased after replacement of a catalyst. Very recently, however, patients have started to report symptoms that suggest a new allergic reaction from polyether impression materials. Here, we report on the results of allergy testing with polyether impression materials as well as with its components. Eight patients with clinical symptoms of a contact allergy (swelling, redness or blisters) after exposure to a polyether impression material were subjected to patch tests, two of them additionally to a prick test. A further patient with atypical symptoms of an allergy (nausea and vomiting after contact with a polyether impression material in the oral cavity) but with a history of other allergic reaction was also patch tested. The prick tests showed no immediate reactions in the two patients tested. In the patch tests, all eight patients with typical clinical symptoms showed positive reactions to the mixed polyether impression materials, to the base paste or to a base paste component. The patient with the atypical clinical symptoms did not show any positive patch test reactions. Polyether impression materials may evoke type IV allergic reactions. The causative agent was a component of the base paste. In consideration of the widespread use of this impression material (millions of applications per year) and in comparison to the number of adverse reactions from other dental materials, the number of such allergic reactions is very low. In very scarce cases, positive allergic reactions to polyether impression materials are possible.

A survey of collection development for United States Medical Licensing Examination (USMLE) and National Board Dental Examination (NBDE) preparation material.

Science.gov (United States)

Hendrix, Dean; Hasman, Linda

2008-07-01

The research sought to ascertain medical and dental libraries' collection development policies, evaluation methods, purchase decisions, and issues that relate to print and electronic United States Medical Licensing Examination (USMLE) and National Board Dental Examination (NBDE) preparation materials. The investigators surveyed librarians supporting American Association of Medical Colleges (AAMC)-accredited medical schools (n = 58/125) on the USMLE and librarians supporting American Dental Association (ADA)-accredited dental schools (n = 23/56) on the NBDE. The investigators analyzed the data by cross-tabulating and filtering the results using EFM Continuum web survey software. Investigators also surveyed print and electronic USMLE and NBDE preparation materials from 2004-2007 to determine the number of publications and existence of reviews. A majority of responding AAMC libraries (62%, n = 58) provide at least 1 electronic or online USMLE preparation resource and buy an average of 11.6 print USMLE titles annually. Due to a paucity of NBDE print and electronic resources, ADA libraries bought significantly fewer print resources, and only 1 subscribed to an electronic resource. The most often reported evaluation methods for both populations were feedback from medical or dental students, feedback from medical or dental faculty, and online trials. Some AAMC (10%, n = 58) and ADA libraries (39%, n = 23) libraries reported that no evaluation of these materials occured at their libraries. From 2004-2007, publishers produced 45 USMLE preparation resources (total n = 546) to every 1 NBDE preparation resource (total n = 12). Users' needs, institutional missions and goals, financial status, and official collection policies most often underlie decisions to collect or not collect examination preparation materials. Evaluating the quality of examination preparation materials can be problematic due to lack of published reviews, lack of usability testing by libraries, and

Dental Anomalies and Dental Age Assessment in Treated Children with Acute Lymphoblastic Leukemia

OpenAIRE

Khojastepour, L; Zareifar, S; Ebrahimi, M

2014-01-01

Background This cross sectional study was performed to evaluate dental ages and incidence of dental anomalies in children treated for acute lymphoblastic leukemia (ALL). Methods and materials A total of 25 ALL patient who passed at least 2 years of chemotherapy and 25 healthy sex and age matched children were evaluated. Dental age as well as dental anomalies in shape, size, number, and structure was recorded based on their panoramic radiographies which were taken for dental purposes. Results ...

Economic impact of dental hygienists on solo dental practices.

Science.gov (United States)

Lazar, Vickie F; Guay, Albert H; Beazoglou, Tryfon J

2012-08-01

The fact that a significant percentage of dentists employ dental hygienists raises an important question: Are dental practices that utilize a dental hygienist structurally and operationally different from practices that do not? This article explores differences among dental practices that operate with and without dental hygienists. Using data from the American Dental Association's 2003 Survey of Dental Practice, a random sample survey of U.S. dentists, descriptive statistics were used to compare selected characteristics of solo general practitioners with and without dental hygienists. Multivariate regression analysis was used to estimate the effect of dental hygienists on the gross billings and net incomes of solo general practitioners. Differences in practice characteristics--such as hours spent in the practice and hours spent treating patients, wait time for a recall visit, number of operatories, square feet of office space, net income, and gross billings--were found between solo general practitioners who had dental hygienists and those who did not. Solo general practitioners with dental hygienists had higher gross billings. Higher gross billings would be expected, as would higher expenses. However, net incomes of those with dental hygienists were also higher. In contrast, the mean waiting time for a recall visit was higher among dentists who employed dental hygienists. Depending on personal preferences, availability of qualified personnel, etc., dentists who do not employ dental hygienists but have been contemplating that path may want to further research the benefits and opportunities that may be realized.

Some aspects of the formulation of alginate dental impression materials--setting characteristics and mechanical properties.

Science.gov (United States)

Nallamuthu, Navina A; Braden, Michael; Patel, Mangala P

2012-07-01

To study the role of the various components of alginate dental impression materials. Experimental materials were formulated and their physical properties characterized and compared to commercially available counterparts (Neocolloid, Palgat Plus and Blueprint Cremix). Properties examined were: dimensional stability and weight change in water and artificial saliva; setting behavior; Shore A hardness and tear energy. The role of magnesium oxide was also investigated. Weight changes in water and artificial saliva can be attributed to an initial thermodynamic potential owing to the ionic content of the alginate, causing water to diffuse into the material. Water is then driven back out following a reversal of this potential. Hardness results for experimental materials were within the range obtained from the commercial materials. The hardness value for an experimental formulation that did not contain magnesium oxide was lower than values from the other experimental materials that did. Tear energies for all three experimental materials were greater than those of the commercial products. There were statistically significant differences between the two experimental materials that contained magnesium oxide and one that did not. With regard to setting time, statistically significant differences were seen between commercial materials and two of the experimental materials. The experimental material that did not contain magnesium oxide had a considerably longer setting time than all of the other materials tested. The key role of magnesium oxide in the setting reaction and the effect on hardness have been demonstrated and discussed. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Synthesis of partial stabilized cement-gypsum as new dental retrograde filling material

Energy Technology Data Exchange (ETDEWEB)

Sadhasivam, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China); Chen, Jung-Chih [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan,Taiwan (China); Savitha, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Hsu, Ming-Xiang; Hsu, Chung-King [Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Lin, Chun-Pin [School of Dentistry and Graduate Institute of Clinical Dentistry, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei, Taiwan (China); Lin, Feng-Huei, E-mail: double@ntu.edu.tw [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China)

2012-10-01

The study describes the sol-gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)-gypsum by adding different weight percentage of gypsum (25% PSC + 75% gypsum, 50% PSC + 50% gypsum and 75% PSC + 25% gypsum) to the PSC. The crystalline phase and hydration products of PSC-gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC + 25% gypsum. The developed PSC-gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC-gypsum also had a remarkable antibacterial activity. - Highlights: Black-Right-Pointing-Pointer A new dental retrograde filling material PSC-gypsum was developed. Black-Right-Pointing-Pointer PSC-gypsum cement has shown excellent initial and final setting time as 15-35 min. Black-Right-Pointing-Pointer It not only improved the setting time but also retain the viscosity, 2 Pa{center_dot}s. Black-Right-Pointing-Pointer High alkaline pH of the cement had a remarkable antibacterial activity. Black-Right-Pointing-Pointer Cytotoxicity studies revealed that the synthesized material is highly biocompatible.

Photoabalation in dental hard substances and atheromatous plaques - The efficiency and selectivity criteria for surgery

International Nuclear Information System (INIS)

Jean, B.

1995-01-01

The basic principals of IR photoabalation are relatively easy to understand as long as water is the predominant absorber in the target tissue (e.g. brain tissue, cornea). Dental hard substances are typical target materials for the study of biological materials with low water content (30%) Its main constituent is hydroxyapatit (50%) with maximal absorption at 9.5 μm wavelength. The photoablation efficiency, the collateral thermal damage and the resultant formation of thermally induced surface cracks were investigated. Unlike the 2.95 μm of the Er:YAG, already in use, the 9.5 μm radiation minimizes the penetration depth; as a consequence, the volume of heated material per pulse is minimal too and thus thermal cracks - a potential source of caries are avoided. Furthermore at 9.5 μm, the ablation threshold requires a minimal fluence; this is an element of selectivity, limiting photoablation to dentin and enamel, while neighboring gingiva cannot be ablated accidentally. Removal of atherosclerotic plaques for recanalization of obliterated cardiac vessels (laser angioplasty) is a minimally invasive surgical procedure of highest socioeconomic relevance. The rather inhomogeneous composition of apatit and colesterol (both absorbing at 9.5 μm) make plaques a particularly complex target material; while the ablation efficiency has to be high, the related shock wave should be minimal. The open-quote selectivity close-quote criterion of the ablation process must avoid accidental perforation of the underlying vessel walls (composed of connective tissue with high water content), a deadly complication exclamation point Experimental results with FELIX will be demonstrated. Photoacoustic spectroscopy in a recently developed non contact mode has been proved to provide various informations (on line) about the IR-photoablation process

Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

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Alejandro Victoria-Escandell

2017-01-01

Full Text Available Human dental pulp stem cells (HDPSCs are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white, an epoxy resin sealant (AH-Plus cement, and an MTA-based cement sealer (MTA-Fillapex. Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed.

Factors Influencing The Selection Of Dental Nursing As A Profession ...

African Journals Online (AJOL)

Objective: To provide a current description of dental nursing students and to assess the reasons for choosing the dental nursing career. Methods: Between 2008 and 2009, a questionnaire survey was administered to 85 dental nursing students from 3 Colleges of Health Technology undergoing external clinical posting in ...

Disparity in dental attendance among older adult populations: a comparative analysis across selected European countries and the USA.

Science.gov (United States)

Manski, Richard; Moeller, John; Chen, Haiyan; Widström, Eeva; Listl, Stefan

2016-02-01

The current study addresses the extent to which diversity in dental attendance across population subgroups exists within and between the USA and selected European countries. The analyses relied on 2006/2007 data from the Survey of Health, Ageing and Retirement in Europe (SHARE) and 2004-2006 data from the Health and Retirement Study (HRS) in the USA for respondents≥51 years of age. Logistic regression models were estimated to identify impacts of dental-care coverage, and of oral and general health status, on dental-care use. We were unable to discern significant differences in dental attendance across population subgroups in countries with and without social health insurance, between the USA and European countries, and between European countries classified according to social welfare regime. Patterns of diverse dental use were found, but they did not appear predominately in countries classified according to welfare state regime or according to the presence or absence of social health insurance. The findings of this study suggest that income and education have a stronger, and more persistent, correlation with dental use than the correlation between dental insurance and dental use across European countries. We conclude that: (i) higher overall rates of coverage in most European countries, compared with relatively lower rates in the USA, contribute to this finding; and that (ii) policies targeted to improving the income of older persons and their awareness of the importance of oral health care in both Europe and the USA can contribute to improving the use of dental services. © 2015 FDI World Dental Federation.

21 CFR 872.3240 - Dental bur.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental bur. 872.3240 Section 872.3240 Food and... DENTAL DEVICES Prosthetic Devices § 872.3240 Dental bur. (a) Identification. A dental bur is a rotary... materials intended for use in the fabrication of dental devices. (b) Classification. Class I (general...

Effect of fluoride addition on the properties of dental alginate impression materials.

Science.gov (United States)

Lee, Yong-Keun; Lim, Bum-Soon; Kim, Cheol-We

2004-03-01

Fluoride-containing dental alginate impression materials can exert a considerable reduction in enamel solubility. The objective was to evaluate the effects of fluoride addition in the alginate impression materials on the properties and subsequent release of fluoride. Four experimental alginate impression materials were studied. Materials were mixed with distilled water (control) or 100-ppm fluoride solution. One or two percent NaF, or 1% SnF2 was added to the materials, which were mixed with distilled water. Fluoride release, flexibility, recovery from deformation, setting time, compressive strength and elastic modulus were determined in accordance with the ISO 1563 and ANSI/ADA Spec. 18. Fluoride release increased after addition of fluoride, and the released amount was 0.762-14.761 ppm. Addition of NaF or SnF2 resulted in higher fluoride release than the control group (p alginate impression material may result in effective release of fluoride without deteriorating the properties of material itself.

[An application of electrochemical detector to dental pharmacology].

Science.gov (United States)

Sakai, J

1990-03-01

The electrochemical detection (ECD) is highly sensitive and can distinguish selectively electrochemically active materials. A sensitive and selective ECD is widely used for high-performance liquid chromatography (HPLC) of phenolic compounds, such as catecholamines, indoleamines and phenolic steroids in biological materials. In the present study, the HPLC/ECD system was applied for the simultaneous determination of various dental drugs, such as phenol, guaiacol, m-cresol, o-chlorophenol, p-chlorophenol, m-chlorophenol, eugenol, pyrogallol and resorcin. As a compromise between sensitivity and stability, the applied voltage was set at 1.2 V vs the reference electrode. These drugs were rapidly and selectively separated on a reversed-phase column using 10 mM acetate buffer (pH 4.0)-methanol (7:3, v/v) as a mobile phase. The detection limits of these drugs were determined to be 0.25 pmol per injection. These results imply that the HPLC/ECD method should be capable of determining these dental drugs with high sensitivity. The ECD was also applied to determine the enzyme activity. A highly sensitive and specific assay for alkaline and acid phosphatases and N-acetyl-beta-glucosaminidase in biological materials, such as plasma, saliva and bone, has been established. Phenol, formed enzymatically from the substrate, was determined by HPLC/ECD. The retention time of phenol was 7 min and no other peaks were observed. The method is rapid and sensitive with a detection limit for phenol of as little as 0.5 pmol. Thus, as little as 0.5 microliters of rat plasma or 10 microliters of human saliva is all that is required for both alkaline and acid phosphatase assays. The assay is accurate and reproducible. Using this assay, alkaline and acid phosphatase activities in human saliva and in rat saliva elicited by pilocarpine and isoproterenol were determined. It will be possible to apply this new assay method to extremely small biological samples. Thus, the application of the HPLC

Evaluation of dental erosion prevalence and contributing factors in patients referring to yazd dental school in 2012-2013

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Farnaz Farahat

2016-03-01

Full Text Available Background and Aims: Dental erosion refers to the loss of tooth structure by being scratched chemically without bacterial involvement which needs to care about due to its prevalence and treatment problems. This study was designed with the aim of evaluation of the frequency of dental erosion and its causing factors in patients referring to yazd dental school in 2012-2013. Materials and Methods: In this cross-sectional study, 400 patients referring to yazd dental school were randomly selected. All of their teeth were evaluated in three surfaces (buccal, lingual and occlusal. The BEWE score was used for classification the extent of damages. Also, patients were given a questionnaire that included patient demographic information and questions to investigate the causes of dental erosion. Data were analyzed using SPSS version 17 and Mann-Whiney, Fisher exact, and Chi-square tests. Results: In this study, 138 men and 261 women were participated with the mean age of 33.26±10.83. 84 persons (21.1% had erosion. There was a direct and significant relationship between the dental erosion and patient's age (P >0.001. Also, there was a direct relationship between the dental erosion and reflux and consumption of lemon and pickle, beverages, soft beer and juice (P>0.001. Conclusion: Consumption of lemon and pickle, beverages, soft beer and juice increases the risk of erosion. Considering the prevalence of dental erosion in about 21% of patients, it is necessary to pay more attention to the knowledge of the causes of erosion and reduction strategies of it.

Material selection for an aerospace component

OpenAIRE

Jönsson, Gustav

2015-01-01

In the world of today there is a drive for lighter and more effective products for various reasons e.g. reduced environmental impact, higher payload, fuel efficiency etc. There is also an expanding development of new materials for a large number of different applications. This makes it more and more difficult for engineers to make good material selections. This has led to the development of a large amount of material selection methods that require more or less effort to select material. An ef...

Study on frequency of dental developmental alterations in a MEXICAN school-based population

OpenAIRE

Ledesma Montes, Constantino; Garcés Ortíz, Maricela; Salcido García, Juan Francisco; Hernández Flores, Florentino

2016-01-01

Background The aim of this study was to know the distribution of dental developmental alterations in the population requesting stomatological attention at the Admission and Diagnosis Clinic of our institution in Mexico City. Material and Methods We reviewed the archives and selected those files with developmental dental alterations. Analyzed data were diagnoses, age, gender, location and number of involved teeth. Results Of the 3.522 patients reviewed, 179 (5.1%) harbored 394 developmental de...

Finite element analysis (FEA) of dental implant fixture for mechanical stability and rapid osseointegration

Science.gov (United States)

Tabassum, Shafia; Murtaza, Ahmar; Ali, Hasan; Uddin, Zia Mohy; Zehra, Syedah Sadaf

2017-10-01

For rapid osseointegration of dental implant fixtures, various surface treatments including plasma spraying, hydroxyapatite coating, acid-etching, and surface grooving are used. However undesirable effects such as chemical modifications, loss of mechanical properties, prolonged processing times and post production treatment steps are often associated with these techniques. The osseointegration rate of the dental implants can be promoted by increasing the surface area of the dental implant, thus increasing the bone cells - implant material contact and allow bone tissues to grow rapidly. Additive Manufacturing (AM) techniques can be used to fabricate dental implant fixtures with desirable surface area in a single step manufacturing process. AM allows the use of Computer Aided Designing (CAD) for customised rapid prototyping of components with precise control over geometry. In this study, the dental implant fixture that replaces the tooth root was designed on commercially available software COMSOL. Nickel - titanium alloy was selected as build materials for dental implant. The geometry of the dental fixture was varied by changing the interspacing distance (thread pitch) and number of threads to increase the total surface area. Three different microstructures were introduced on the surface of dental implant. The designed models were used to examine the effect of changing geometries on the total surface area. Finite Element Analysis (FEA) was performed to investigate the effect of changing geometries on the mechanical properties of the dental implant fixtures using stress analysis.

Nordic dentists' opinions on the safety of amalgam and other dental restorative materials.

Science.gov (United States)

Widström, E; Haugejorden, O; Sundberg, H; Birn, H

1993-08-01

The safety of amalgam and other restorative materials has caused concern among dental patients in recent years. The aim of this study was to obtain information on dentists' perceived competence in handling different filling materials and their opinions on the safety of these. A random sample of practising dentists in Denmark, Finland, Norway, and Sweden received a mail questionnaire in spring 1990. Answers were received from 1732 dentists (65%). The study showed that the respondents believed that their theoretic knowledge and clinical skills were generally at a high level regarding restorative materials. The risks of the side-effects of gold, ceramic materials, and glass ionomer were considered to be low by about 90% of the respondents. Amalgam was considered to be significantly more hazardous by the Swedish respondents than the others. Interestingly, composite was considered to be associated with a high risk of side-effects by about half of the dentists in all Nordic countries. The dentists' opinions were not found to be greatly influenced by their sex, age, or place of residence but rather by their country and service sector. Against the background of the present lack of scientific evidence on the hazardousness of amalgam or other restorative materials for patients' general health, these findings indicate that dentists are influenced by discussions in the mass media about dental treatment and materials and, of course, by the guidelines given by the health authorities in their own countries. Few dentists were shown to be concerned about occupational risks associated with the use of amalgam, and they had not had their own amalgam fillings replaced.(ABSTRACT TRUNCATED AT 250 WORDS)

THE PREVALENCE OF DENTAL ANOMALIES IN A TURKISH POPULATION

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Gamze Aren

2015-10-01

Full Text Available Purpose: The aim of the present study was to investigate the prevalence of dental anomalies in a Turkish population according to the gender and age. Materials and Methods: A retrospective study was performed using panoramic radiographs of 2025 patients (885 males and 1140 females ranging in age from 9 to 35 (mean age 25.61±10.04 years attending Department of Oral Radiology, University of Istanbul, Faculty of Dentistry. These patients were examined to determine the presence of developmental dental anomalies involving hypodontia, hyperdontia, microdontia, taurodontism and other root anomalies. The incidence of these anomalies were assessed according to the gender and age. Results: Among the 2025 subjects, a total of 96 individuals (42 males and 54 females showed at least one of the selected dental anomalies (4.74%. Tooth agenesis was the most common dental abnormality (1.77% followed by taurodontism (1.18%, hyperdontia (0.79%, microdontia (0.54% and root anomalies (0.44%, respectively. Conclusion: Tooth agenesis is the most common developmental dental anomaly in the studied Turkish population followed by taurodontism.

Dental neglect among college going adolescents in Virajpet, India

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Sunil Lingaraj Ajagannanavar

2014-01-01

Full Text Available Introduction: Dental neglect (DN has been defined as behavior and attitudes which are likely to have detrimental consequences for the individual′s oral health, or more specifically as failure to take precautions to maintain oral health, failure to obtain needed dental care, and physical neglect of the oral cavity. Aim: The aim was to assess the association of DN with dental caries and oral hygiene among adolescents in Virajpet, India. Materials and Methods: A total of six hundred adolescents aged 15-18 years were selected. DN was recorded using self-administered questionnaire. Oral health status was clinically assessed using simplified oral hygiene index (OHI-S and dental caries through dentition status as per WHO criteria. Results: The mean DN score for this population was 10.18. Sociodemographic variables and Dental Attendance pattern were significantly associated with DN. Mean decayed missing filled value and OHI-S values were also significantly associated with DN. Conclusion: The present study revealed that variations in DN exist in relation to sociodemographic characteristics and pattern of dental attendance. In addition, oral health status was significantly associated with DN among adolescents.

The Validity of Subjects in Korean Dental Technicians' Licensing Examination

Directory of Open Access Journals (Sweden)

Woong-chul Kim

2005-06-01

Full Text Available This study prepared a basic framework for the development and improvement of Korean Dental Technicians' Licensing Examination, based on actual test questions. A peer review was conducted to ensure relevance to current practices in dental technology. For the statistical analysis, 1000 dental laboratory technicians were selected; specialists in dental laboratory technology (laboratory owners, educators, etc. were involved in creating valid and reliable questions. Results indicated that examination subjects should be divided into three categories: basic dental laboratory theory, dental laboratory specialties, and a practical examination. To ensure relevance to current practice, there should be less emphasis on basic dental laboratory theory, including health-related laws, and more emphasis on dental laboratory specialties. Introduction to dental anatomy should be separated from oral anatomy and tooth morphology; and fixed prosthodontics should be separated from crown and bridge technology and dental ceramics technology. Removable orthodontic appliance technology should be renamed 'orthodontic laboratory technology'. There should be less questions related to health related law, oral anatomy, dental hygiene, dental materials science and inlay, while the distribution ratio of questions related to tooth morphology should be maintained. There should be a decrease in the distribution ratio of questions related to crown and bridge technology, dental ceramics technology, complete dentures and removable partial dentures technology, and orthodontic laboratory technology. In the practical examination, the current multiple choice test should be replaced with tooth carving using wax or plaster. In dental laboratory specialties, subjects related to contemporary dental laboratory technology should be included in the test items.

A Deep Morphological Characterization and Comparison of Different Dental Restorative Materials

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R. Condò

2017-01-01

Full Text Available Giomer is a relatively new class of restorative material with aesthetics, handling and physical properties of composite resins, and benefits of glass ionomers: high radiopacity, antiplaque effect, fluoride release, and recharge. To verify the superior properties of Giomers, in this study, a deep morphological characterization has been performed with an in vitro comparative study among a Giomer (Beautifil® II by Shofu Dental Corporation, Osaka, Japan, a Compomer (Dyract Extra by Dentsply, Caulk, Germany, glass ionomer cement (Ketac fil plus by 3M ESPE, and a composite resin (Tetric Evoceram by Ivoclar. In particular, mechanical and optical properties and ageing effects have been compared to investigate materials similarities and differences. Indentation tests, UV-Visible spectroscopy, Raman spectroscopy, and weight loss after storage in saliva or sugary drink have been carried out to analyze materials behavior in real conditions. The results confirm the high quality of Giomer material and indicate possible improvements in their usage.

The performance of human dental pulp stem cells on different three-dimensional scaffold materials.

NARCIS (Netherlands)

Zhang, W.; Walboomers, X.F.; Kuppevelt, A.H.M.S.M. van; Daamen, W.F.; Bian, Z.; Jansen, J.A.

2006-01-01

The aim of this study was to investigate the in vitro and in vivo behavior of human dental pulp stem cells (DPSCs) isolated from impacted third molars, when seeded onto different 3-dimensional (3-D) scaffold materials: i.e. a spongeous collagen, a porous ceramic, and a fibrous titanium mesh.

The effects of selected dietary bioflavonoid supplementation on dental caries in young rats fed a high-sucrose diet.

Science.gov (United States)

Wood, Nelson

2007-12-01

Recent evidence suggests that certain bioflavonoids reduce dental caries and cariogenic bacteria incidence. The present study evaluates two separate, but related, dietary trials -- trial 1, 0.09%, 0.18%, 0.36%, and 0.72% dietary naringenin (NAR) supplementation; and trial 2, 0.57% dietary rutin (R), quercetin (Q), and naringin (N) supplementation-on dental caries formation in 40 different male albino rats, at the expense of dextrose, for periods of 42 days. All rats were fed 40% sucrose. In dietary trial 1, rats were evaluated for dental caries, dental plaque accumulation, and saliva flow rates using oneway analysis of variance, post hoc Tukey's test, Kruskal-Wallis test, and Spearman's correlations. In dietary trial 2, rats were evaluated for occlusal dental caries only using a Kruskal-Wallis H test and analysis of variance. A 5% level of statistical significance was adopted throughout. In dietary trial 1, NAR showed a statistically significant effect on dental caries, plaque, and saliva flow rate reduction compared with the control group (P < .05-.01). An inverse dose-dependent relationship was established among the NAR experimental groups and control group. Dietary NAR supplementation significantly reduced dental caries formation, possibly because of reduced dental plaque accumulation. In dietary trial 2, statistically significant reductions in occlusal caries were observed for R, Q, and N in the maxillary molars and for Q and N in the mandibular molars compared with the control group (P < .05). Significant associations were observed among the experimental groups and maxillary (P < .05) and mandibular (P < .01) occlusal dental caries. Hence, selected bioflavonoids may show promise as an alternative means of reducing dental caries.

Viscoelastic Properties of Dental Pulp Tissue and Ramifications on Biomaterial Development for Pulp Regeneration.

Science.gov (United States)

Erisken, Cevat; Kalyon, Dilhan M; Zhou, Jian; Kim, Sahng G; Mao, Jeremy J

2015-10-01

A critical step in biomaterial selection effort is the determination of material as well as the biological properties of the target tissue. Previously, the selection of biomaterials and carriers for dental pulp regeneration has been solely based on empirical experience. In this study, first, the linear viscoelastic material functions and compressive properties of miniature pig dental pulp were characterized using small-amplitude oscillatory shear and uniaxial compression at a constant rate. They were then compared with the properties of hydrogels (ie, agarose, alginate, and collagen) that are widely used in tissue regeneration. The comparisons of the linear viscoelastic material functions of the native pulp tissue with those of the 3 hydrogels revealed the gel-like behavior of the pulp tissue over a relatively large range of time scales (ie, over the frequency range of 0.1-100 rps). At the constant gelation agent concentration of 2%, the dynamic properties (ie, storage and loss moduli and the tanδ) of the collagen-based gel approached those of the native tissue. Under uniaxial compression, the peak normal stresses and compressive moduli of the agarose gel were similar to those of the native tissue, whereas alginate and collagen exhibited significantly lower compressive properties. The linear viscoelastic and uniaxial compressive properties of the dental pulp tissue reported here should enable the more appropriate selection of biogels for dental pulp regeneration via the better tailoring of gelation agents and their concentrations to better mimic the dynamic and compressive properties of native pulp tissue. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of Glove Damage during Dental Procedures among Dental Specialists in Tabriz

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Saeed Nezafati

2007-08-01

Full Text Available

Background and aims. Dental practitioners are prone to occupational risk of infection. This can be prevented in part by wearing gloves. However, for this to be effective, gloves should be intact during the entire course of dental procedure. Leaky surgical latex gloves have been seen in 0.9% of cases before use. As much as 1.9% of latex gloves have been reported to be damaged during dental procedures. In this study, we decided to assess glove damage during dental procedures among dental specialists in Tabriz.

Materials and methods. Thirty-six dental specialists were selected for this study. Each practitioner received 40 pairs of intact powdered latex gloves. Upon the completion of dental procedures, the gloves were retrieved and any tears were evaluated separately for right and left hands. Data was analyzed using chi-square test.

Results. 159 punctures were detected in 144 gloves (5% out of 2880 unpaired gloves used by practitioners. They noticed the tear(s in 60 cases (2%, however, 99 cases (3% of tear(s were not noted during the procedure. The highest rate of glove damage was observed in the prosthodontists’ group (12.3%, which was statistically significant comparing to other groups (p=0.048. The lowest rate of the damage was observed in the oral surgeons’ group (2% which showed no significant difference (p=0.134. The highest rate of punctures in the gloves was observed in the first and second fingers of the non-dominant hand.

Conclusion. The damage to 5% of the gloves is highly significant, with a potential role in occupational hazards. The higher rate of leaks in the prosthodontists’ group compared to other groups demands for greater prudence in this field. The high rate of leaks in the first and second fingers of the non-dominant hand requires more attention to this area during daily practice.

Neurological symptoms among dental assistants: a cross-sectional study.

Science.gov (United States)

Moen, Be; Hollund, Be; Riise, T

2008-05-18

Dental assistants help the dentist in preparing material for filling teeth. Amalgam was the filling material mostly commonly used in Norway before 1980, and declined to about 5% of all fillings in 2005. Amalgam is usually an alloy of silver, copper, tin and mercury. Copper amalgam, giving particularly high exposure to mercury was used in Norway until 1994. Metallic mercury is neurotoxic. Few studies of the health of dental assistants exist, despite their exposure to mercury. There are questions about the existence of possible chronic neurological symptoms today within this working group, due to this exposure. The aim of this study was to compare the occurrence of neurological symptoms among dental assistants likely to be exposed to mercury from work with dental filling material, compared to similar health personnel with no such exposure. All dental assistants still at work and born before 1970 registered in the archives of a trade union in Hordaland county of Norway were invited to participate (response rate 68%, n = 41), as well as a similar number of randomly selected assistant nurses (response rate 87%, n = 64) in the same age group. The participants completed a self-administered, mailed questionnaire, with questions about demographic variables, life-style factors, musculoskeletal, neurological and psychosomatic symptoms (Euroquest). The dental assistants reported significant higher occurrence of neurological symptoms; psychosomatic symptoms, problems with memory, concentration, fatigue and sleep disturbance, but not for mood. This was found by analyses of variance, adjusting for age, education, alcohol consumption, smoking and personality traits. For each specific neurological symptom, adjusted logistic regression analyses were performed, showing that these symptoms were mainly from arms, hands, legs and balance organs. There is a possibility that the higher occurrence of neurological symptoms among the dental assistants may be related to their previous work

Neurological symptoms among dental assistants: a cross-sectional study

Directory of Open Access Journals (Sweden)

Hollund BE

2008-05-01

Full Text Available Abstract Background Dental assistants help the dentist in preparing material for filling teeth. Amalgam was the filling material mostly commonly used in Norway before 1980, and declined to about 5% of all fillings in 2005. Amalgam is usually an alloy of silver, copper, tin and mercury. Copper amalgam, giving particularly high exposure to mercury was used in Norway until 1994. Metallic mercury is neurotoxic. Few studies of the health of dental assistants exist, despite their exposure to mercury. There are questions about the existence of possible chronic neurological symptoms today within this working group, due to this exposure. The aim of this study was to compare the occurrence of neurological symptoms among dental assistants likely to be exposed to mercury from work with dental filling material, compared to similar health personnel with no such exposure. Methods All dental assistants still at work and born before 1970 registered in the archives of a trade union in Hordaland county of Norway were invited to participate (response rate 68%, n = 41, as well as a similar number of randomly selected assistant nurses (response rate 87%, n = 64 in the same age group. The participants completed a self-administered, mailed questionnaire, with questions about demographic variables, life-style factors, musculoskeletal, neurological and psychosomatic symptoms (Euroquest. Results The dental assistants reported significant higher occurrence of neurological symptoms; psychosomatic symptoms, problems with memory, concentration, fatigue and sleep disturbance, but not for mood. This was found by analyses of variance, adjusting for age, education, alcohol consumption, smoking and personality traits. For each specific neurological symptom, adjusted logistic regression analyses were performed, showing that these symptoms were mainly from arms, hands, legs and balance organs. Conclusion There is a possibility that the higher occurrence of neurological symptoms

Radiographic Assessment of Dental Maturation in Children With Dental Agenesis.

Science.gov (United States)

Medina, Aida Carolina; Pozo, Rodrigo Del; de Cedres, Lucila Blanco

Dental agenesis is the most common developmental anomaly in humans, frequently associated with disorders in dental development and maturation. The purpose of this study is to determine radiographic variations in dental maturation in a group of Venezuelan children with dental agenesis. 1,188 panoramic radiographs, from healthy patients ages 5 to 12 years old were studied for agenesis of permanent teeth. Dental maturation was assessed by relative eruption and dental age according to Nolla, comparing children affected with dental agenesis to a stratified control group selected from the same population, excluding children with premature loss of primary teeth in the left quadrants and unclear radiographs. Descriptive analysis, and differences between means and medians (Student t test, Kruskall-Wallis p=0.05) were performed. Medians for Nolla stages were similar between groups, with delay in tooth formation in the agenesis group for second molars (p<0.05) and maxillary lateral incisors and second premolars. Dental age was significantly underestimated for both groups, -0.89 (±0.78) for the control group and -1.20 (±0.95) for the study group. Tooth eruption was similar between groups. Dental age was significantly delayed in Venezuelan children with dental agenesis, with variable significance for tooth formation of studied teeth.

Suitability of Different Natural and Synthetic Biomaterials for Dental Pulp Tissue Engineering.

Science.gov (United States)

Galler, Kerstin M; Brandl, Ferdinand P; Kirchhof, Susanne; Widbiller, Matthias; Eidt, Andreas; Buchalla, Wolfgang; Göpferich, Achim; Schmalz, Gottfried

2018-02-01

Dental pulp tissue engineering is possible after insertion of pulpal stem cells combined with a scaffold into empty root canals. Commonly used biomaterials are collagen or poly(lactic) acid, which are either difficult to modify or to insert into such a narrow space. New hydrogel scaffolds with bioactive, specifically tailored functions could optimize the conditions for this approach. Different synthetic and natural hydrogels were tested for their suitability to engineer dental pulp. Two functionalized modifications of polyethylene glycol were developed in this study and compared to a self-assembling peptide, as well as to collagen and fibrin. Cell viability of dental pulp stem cells in test materials was assessed over two weeks. Cells in selected test materials laden with dentin-derived growth factors were inserted into human tooth roots and implanted subcutaneously into immunocompromised mice. In vitro cell culture exhibited distinct differences between scaffold types, where viability was significantly higher in natural compared to synthetic materials. In vivo experiments showed considerable differences regarding scaffold degradation, soft tissue formation, vascularization, and odontoblast-like cell differentiation. Fibrin appeared most suitable to enable generation of a pulp-like tissue and differentiation of cells into odontoblasts at the cell-dentin interface. In conclusion, natural materials, especially fibrin, proved to be superior compared to synthetic scaffolds regarding cell viability and dental pulp-like tissue formation.

Dental Sealants: Knowledge, Value, Opinion, and Practice among Dental Professionals of Bathinda City, India

OpenAIRE

Asawa, Kailash; Gupta, Vivek V.; Tak, Mridula; Nagarajappa, Ramesh; Chaturvedi, Pulkit; Bapat, Salil; Mishra, Prashant; Roy, Santanu Sen

2014-01-01

Objective. The purpose of the study was to assess the knowledge, value, opinion, and practice regarding use of dental sealants among private dental practitioners in Bathinda City, Punjab, India. Materials and Methods. A cross-sectional survey was conducted among all private dental practitioners in Bathinda City, Punjab. A self-administered structured questionnaire consisting of 28 items was used to assess their knowledge, value, opinion, and practice regarding dental sealants. One-way analysi...

Surface texture measurement for dental wear applications

Science.gov (United States)

Austin, R. S.; Mullen, F.; Bartlett, D. W.

2015-06-01

The application of surface topography measurement and characterization within dental materials science is highly active and rapidly developing, in line with many modern industries. Surface measurement and structuring is used extensively within oral and dental science to optimize the optical, tribological and biological performance of natural and biomimetic dental materials. Although there has historically been little standardization in the use and reporting of surface metrology instrumentation and software, the dental industry is beginning to adopt modern areal measurement and characterization techniques, especially as the dental industry is increasingly adopting digital impressioning techniques in order to leverage CAD/CAM technologies for the design and construction of dental restorations. As dental treatment becomes increasingly digitized and reliant on advanced technologies such as dental implants, wider adoption of standardized surface topography and characterization techniques will become evermore essential. The dental research community welcomes the advances that are being made in surface topography measurement science towards realizing this ultimate goal.

Child dental anxiety, parental rearing style and dental history reported by parents

NARCIS (Netherlands)

Krikken, J.B.; van Wijk, A.J.; ten Cate, J.M.; Veerkamp, J.S.

2013-01-01

AIM: To examine the relationship between self-reported parental rearing style, parent's assessment of their child's dental anxiety and the dental history of children. MATERIALS AND METHODS: Parents of primary school children were asked to complete questionnaires about their parenting style, using

An interview study of persons who attribute health problems to dental filling materials--part two in a triangulation study on 65 and 75 years old Swedes.

Science.gov (United States)

Ståhlnacke, Katri; Söderfeldt, Björn

2013-01-01

Dental materials are perceived as a health problem by some people, although scientists do not agree about possible causes of such problems. The aim of this paper was to gain a deeper knowledge and understanding of experiences from living with health problems attributed to dental materials. Addressed topics were the type of problem, both as to general and oral health, perceived causes of the problems,their experienced effect on life, and reception by health professionals. Persons, who in a previous large questionnaire study had answered that they had experienced troubles from dental materials and also agreed to answer follow-up questions, were contacted with a request to take part in an interview study. Eleven individual interviews were held.The interviews were transcribed verbatim and the material was analysed according to the Qualitative Content Analysis method. Meaning units were extracted and condensed into a number of codes, which were combined into subcategories, categories, and themes. Four themes were identified: 1) Long-term oral, mental, and somatic difficulties of varying character, caused by dental amalgam. 2) Problems treated mainly by replacement of dental material in fillings. 3) Powerful effects on life, mostly negative. 4) The reception by health professionals was generally good, but with elements of encounters where they felt treated with nonchalance and lack of respect. In conclusion, people who attributed their health difficulties to dental materials had a complex range of problems and the perception was that amalgam/mercury was the cause of the troubles. The reception from health professionals was perceived as generally good, although with occasional negative experiences.

Entrepreneurship in continuing dental education: a dental school perspective.

Science.gov (United States)

Liberto, Vincent N

2005-01-01

The definition of continuing dental education is presented, along with its benefits to the profession. The preeminence of dental schools in providing lifelong learning opportunities and freedom from commercial involvement that existed even twenty years ago has changed. Less than a quarter of CE takes place in school, and the focus there is increasingly on material with deep scientific background and hands-on learning. The newest innovations and those with the greatest commercial potential are taught elsewhere. Proposed changes in the ADA CERP standards would take on a "purist" approach that could place dental schools at a severe disadvantage while allowing "for profit" institutes to flourish and thus further undermine the role dental schools can play in providing quality professional development experiences.

Dental Caries (Tooth Decay)

Science.gov (United States)

... Materials Contact Us Home Research Data & Statistics Dental Caries (Tooth Decay) Dental caries (tooth decay) remains the most prevalent chronic disease ... adults, even though it is largely preventable. Although caries has significantly decreased for most Americans over the ...

Eco-Material Selection for Auto Bodies

Energy Technology Data Exchange (ETDEWEB)

Mayyas, Ahmad T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Omar, Mohammed [Masdar Institute of Science & Technology; Hayajneh, Mohammed T. [Jordan University of Science and Technology

2017-09-25

In the last decades, majority of automakers started to include lightweight materials in their vehicles to meet hard environmental regulations and to improve fuel efficiency of their vehicles. As a result, eco-material selection for vehicles emerged as a new discipline under design for environment. This chapter will summarize methods of eco-material selections for automotive applications with more emphasis into auto-bodies. A set of metrics for eco-material selection that takes into account all economic, environmental and social factors will be developed using numerical and qualitative methods. These metrics cover products' environmental impact, functionality and manufacturability, in addition to the economic and societal factors.

Spectrally selective solar energy materials

International Nuclear Information System (INIS)

Sikkens, M.

1981-01-01

The performance and properties of spectrally selective materials are considered and, in particular, the selective absorption of solar radiation by free electrons is discussed, both in a homogeneous material in which these electrons are strongly scattered, and in a composite material consisting of small metal particles in a dielectric host. Such materials can be used as selective absorbers if they are deposited as a thin film onto a metal substrate, the latter providing the required low emittance. This type of selective surfaces is produced by reactive sputtering of Ni in an Ar/CH 4 gas mixture. This method can yield Ni films with a considerable carbon concentration. The carbon concentration can be varied over a wide range by adjusting the partial methane pressure. The associated experimental techniques are discussed. As the carbon concentration increases, the structure of the films changes from a Ni phase in which carbon is dissolved, via an intermediate Ni 3 C phase into an amorphous carbon phase with a high electrical resistivity in which small nickel particles are embedded. Both mechanisms of selective absorption by free electrons are observed and are found to be well described by rather simple models. The best selectivity is obtained at high carbon concentrations where the films consist of nickel particles in carbon. Depending on the film thickness and the substrate material, the solar absorptance varies between 0.78 and 0.90, while the thermal emittance varies between 0.025 and 0.04. Since the films are found to be stable at 400 0 C in vacuum, it appears that these films are good candidates for application in photothermal solar energy conversion at temperature levels around 200 0 C and higher. (Auth.)

Selective interference with pacemaker activity by electrical dental devices.

Science.gov (United States)

Miller, C S; Leonelli, F M; Latham, E

1998-01-01

We sought to determine whether electromagnetic interference with cardiac pacemakers occurs during the operation of contemporary electrical dental equipment. Fourteen electrical dental devices were tested in vitro for their ability to interfere with the function of two Medtronics cardiac pacemakers (one a dual-chamber, bipolar Thera 7942 pacemaker, the other a single-chamber, unipolar Minix 8340 pacemaker). Atrial and ventricular pacemaker output and electrocardiographic activity were monitored by means of telemetry with the use of a Medtronics 9760/90 programmer. Atrial and ventricular pacing were inhibited by electromagnetic interference produced by the electrosurgical unit up to a distance of 10 cm, by the ultrasonic bath cleaner up to 30 cm, and by the magnetorestrictive ultrasonic scalers up to 37.5 cm. In contrast, operation of the amalgamator, electric pulp tester, composite curing light, dental handpieces, electric toothbrush, microwave oven, dental chair and light, ENAC ultrasonic instrument, radiography unit, and sonic scaler did not alter pacing rate or rhythm. These results suggest that certain electrosurgical and ultrasonic instruments may produce deleterious effects in medically fragile patients with cardiac pacemakers.

Disparity in Dental Attendance Among Older Adult Populations: A Comparative Analysis Across Selected European Countries and the United States

Science.gov (United States)

Manski, Richard; Moeller, John; Chen, Haiyan; Widström, Eeva; Listl, Stefan

2015-01-01

Background The current study addresses the extent to which diversity in dental attendance across population subgroups exists within and between the United States and selected European countries. Method The analyses relied on 2006/2007 data from the Survey of Health, Ageing, and Retirement in Europe (SHARE) and 2004–2006 data from of the Health and Retirement Study (HRS) in the United States for respondents aged 51 years and older. Logistic regression models were estimated to identify impacts of dental care coverage and oral as well as general health status on dental care use. Results We were unable to discern significant differences in dental attendance across population subgroups in countries with and without social health insurance, between the USA and European countries, and between European countries classified by social welfare regime. Patterns of diverse dental use were found, but they did not appear predominately in countries classified by welfare state regime or by presence or absence of social health insurance. Conclusions Findings of this study suggest that income and education have stronger and more persistent correlation with dental use than the correlation between dental insurance and dental use across European countries. We conclude that (1) higher overall rates of coverage in most European countries, compared to relatively lower rates in the USA, contribute to this finding and that (2) policies targeted to improving the income of older persons and their awareness of the importance of oral health care in both Europe and the USA can contribute to improving the use of dental services. PMID:26465093

Imaging of dental material by polarization-sensitive optical coherence tomography

Science.gov (United States)

Dichtl, Sabine; Baumgartner, Angela; Hitzenberger, Christoph K.; Moritz, Andreas; Wernisch, Johann; Robl, Barbara; Sattmann, Harald; Leitgeb, Rainer; Sperr, Wolfgang; Fercher, Adolf F.

1999-05-01

Partial coherence interferometry (PCI) and optical coherence tomography (OCT) are noninvasive and noncontact techniques for high precision biometry and for obtaining cross- sectional images of biologic structures. OCT was initially introduced to depict the transparent tissue of the eye. It is based on interferometry employing the partial coherence properties of a light source with high spatial coherence ut short coherence length to image structures with a resolution of the order of a few microns. Recently this technique has been modified for cross section al imaging of dental and periodontal tissues. In vitro and in vivo OCT images have been recorded, which distinguish enamel, cemento and dentin structures and provide detailed structural information on clinical abnormalities. In contrast to convention OCT, where the magnitude of backscattered light as a function of depth is imaged, polarization sensitive OCT uses backscattered light to image the magnitude of the birefringence in the sample as a function of depth. First polarization sensitive OCT recordings show, that changes in the mineralization status of enamel or dentin caused by caries or non-caries lesions can result in changes of the polarization state of the light backscattered by dental material. Therefore polarization sensitive OCT might provide a new diagnostic imaging modality in clinical and research dentistry.

Accuracy of a new elastomeric impression material for complete-arch dental implant impressions.

Science.gov (United States)

Baig, Mirza R; Buzayan, Muaiyed M; Yunus, Norsiah

2018-05-01

The aim of the present study was to assess the accuracy of multi-unit dental implant casts obtained from two elastomeric impression materials, vinyl polyether silicone (VPES) and polyether (PE), and to test the effect of splinting of impression copings on the accuracy of implant casts. Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant-abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z-axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non-parametrical Kruskal-Wallis and Mann-Whitney tests at α = .05. The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non-splinting and splinting groups were also not significantly different for both PE and VPES (P>.05). The accuracy of VPES impression material seemed comparable with PE for multi-implant abutment-level impressions. Splinting had no effect on the accuracy of implant impressions. © 2018 John Wiley & Sons Australia, Ltd.

Dental Trauma Guide

DEFF Research Database (Denmark)

Andreasen, Jens Ove; Lauridsen, Eva; Gerds, Thomas Alexander

2012-01-01

Diagnosis and treatment for traumatic dental injuries are very complex owing to the multiple trauma entities represented by six luxation types and nine fracture types affecting both the primary and the permanent dentition. When it is further considered that fracture and luxation injuries are often...... problems in selecting proper treatment for some of these trauma types. To remedy this situation, an Internet-based knowledge base consisting of 4000 dental trauma cases with long-term follow up is now available to the public and the professions on the Internet using the address http://www.Dental...

Effect of aromatherapy on dental patient anxiety: A randomized controlled trial

Directory of Open Access Journals (Sweden)

M Venkataramana

2016-01-01

Full Text Available Introduction: Dental anxiety is a common and potentially distressing problem, both for the patients and for dental practitioners. It is considered to be the main barrier and affects the working lives of dental professional potentially compromising their performance. Aim: To know the effect of aromatherapy in the reduction of dental anxiety and to compare the anxiety levels of dental patients with the control group. Materials and Methods: A randomized controlled trial design was used. Of 40 dental clinics in Khammam town, 10 dental clinics were selected by simple random sampling method. A total of 100 patients attending the dental clinic for the first time were included in the study. Ambient odor of lavender was maintained with a candle warmer. A questionnaire comprising demographic information, smoking status, Modified dental anxiety scale (Humphries et al. in 1995, was given to the patients when they were waiting in the waiting room. Student's t-test and ANOVA test were used for data analysis. The level of significance was set at 0.05. Results: Considerable decrease in anxiety scores in 3 age groups was observed. A statistically significant (P = 0.002 decrease with age in mean anxiety score. A significant difference in anxiety scores of lavender group, a significant decrease of anxiety scores with an increase of age. Conclusion: Lavender decreased the current anxiety scores of patients effectively.

Perspectives on providing good access to dental services for elderly people: patient selection, dentists' responsibility and budget management.

Science.gov (United States)

Grytten, Jostein; Holst, Dorthe

2013-06-01

To suggest a model for organizing and financing dental services for elderly people so that they have good access to services. There are few studies on how dental services for elderly people should be organized and financed. This is surprising if we take into consideration the fact that the proportion of elderly people is growing faster than any other group in the population, and that elderly people have more dental diseases and poorer access to dental services than the rest of the adult population. In several countries, dental services are characterized by private providers who often operate in a market with competition and free price-setting. Private dentists have no community responsibility, and they are free to choose which patients they treat. Literature review and critical reasoning. In order to avoid patient selection, a patient list system for elderly people is recommended, with per capita remuneration for the patients that the dentist is given responsibility for. The patient list system means that the dentist assumes responsibility for a well-defined list of elderly people. Our model will lead to greater security in the dentist/patient relationship, and patients with great treatment needs will be ensured access to dental services. © 2012 John Wiley & Sons A/S and The Gerodontology Society. Published by John Wiley & Sons Ltd.

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

OpenAIRE

Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin; Hwang, Hyeon-Shik

2016-01-01

Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions wer...

Predictors of Job Satisfaction in Dental Professionals of the Bosnia and Herzegovina Federation

Directory of Open Access Journals (Sweden)

Vlatka Lajnert

2016-01-01

Full Text Available Introduction: Working in a healthy work environment is the ultimate goal of every employee. Dentistry is a stressful career, and the reasons for dissatisfaction are numerous. Aim: The aim of this study was to determine the factors of work satisfaction in dental professionals of the Bosnia and Herzegovina Federation. Materials and methods: A total of 134 dental professionals selected randomly from the Registry of Dental Chamber of Bosnia and Herzegovina Federation were included in the study. All of them filled out the Demographic Questionnaire and Job Satisfaction Scale (JSS. Results: An increase in the influence of work on the quality of life as well as an increase in its frequency results in leaving the job and significantly reducing the overall job satisfaction. General dental practitioners are significantly more satisfied as compared with specialists. Significant predictors of the job satisfaction are employment status, type of the practice, and availability of dental assistants. General dental practitioners with a dental assistant employed at a private practice are more likely to be satisfied with their jobs. Conclusions: Employment status, practice type and availability of dental assistants are significant predictors of job satisfaction. General dental practitioners working in a private practice with a dental assistant are most likely to be satisfied.

Image Processing Techniques for Assessment of Dental Trays

Science.gov (United States)

2001-10-25

170 patients having Angle Class I molar relationships with minor malocclusions and teeth including second molars fully erupted without loss of tooth...Abstract-A tray selected for the dental patient must adapt to the curvature of the teeth and allow the impression material to be in appropriate...brands of perforated metal trays with 170 lower arch cast models collected from patients having Angle Class 1 type occlusion with minor malocclusions

21 CFR 872.3640 - Endosseous dental implant.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant. 872.3640 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3640 Endosseous dental implant. (a) Identification. An endosseous dental implant is a device made of a material such as titanium or titanium alloy, that...

How does duration of curing affect the radiopacity of dental materials?

Energy Technology Data Exchange (ETDEWEB)

Bejeh Mir, Arash Poorsattar [School of Dentistry, Babol University of Medical Sciences, Babol (Iran, Islamic Republic of); Bejeh Mir, Morvarid Poorsattar [Private Practice of Orthodontics, Montreal (Canada)

2012-06-15

Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs. One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm{sup 2} irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA. Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05). These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

How does duration of curing affect the radiopacity of dental materials?

International Nuclear Information System (INIS)

Bejeh Mir, Arash Poorsattar; Bejeh Mir, Morvarid Poorsattar

2012-01-01

Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs. One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm 2 irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA. Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05). These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.

Unilateral and bilateral dental transpositions in the maxilla

DEFF Research Database (Denmark)

Danielsen, Jakob Christian; Karimian, K; Ciarlantini, R

2015-01-01

and lateral incisor (Type 2). The dentitions were analysed regarding agenesis and dental morphological anomalies on panoramic radiographs, and craniofacial aspects were cephalometrically analysed on profile images The results were statistically evaluated. RESULTS: All groups demonstrated increased occurrences......AIM: This was to elucidate dental and skeletal findings in individuals with unilateral and bilateral maxillary dental transpositions. MATERIAL AND METHODS: The sample comprised of radiographic materials from 63 individuals with maxillary dental transpositions from the Departments of Odontology...... retrognathia (more pronounced in Type 1B). Type 2 showed a significant posterior inclination of the maxilla. CONCLUSION: Transpositions of maxillary canines involve dental and skeletal deviations. Dental deviations were predominantly taurodontic root morphology and agenesis. Regarding skeletal deviations...

Biological evaluation of dental materials, in vitro and in vivo

International Nuclear Information System (INIS)

Kawahara, H.

1982-01-01

In this paper, the correlation between the user of tissue culture for in vitro tests and the tissue irritability and pupal response observed in in vitro tests, will be discussed. It would produce confusion if dental materials were standardised with the unreliable parameter of the living system in dynamic balance. Biological tests, both in vitro and in vivo, should be used for pre-standards testing, without any political control to establish physicochemical standards. As a first step, corrosion tests and the dissolution dosje of toxic components from the material in the tissue culture medium and/or artificial salvia should be standardised under conditions simulating the oral environment. The CNC method and photo-pattern analysis are used for the interpretation of cytotoxicity. The need for biological testing, both in vitro and in vivo, definitely exists in order to obtain physicochemical standards, with a biological simulation depending upon the feedback obtained from the results of in vitro and in vivo tests

Skateboard deck materials selection

Science.gov (United States)

Liu, Haoyu; Coote, Tasha; Aiolos; Charlie

2018-03-01

The goal of this project was to identify the ideal material for a skateboard deck under 200 in price, minimizing the weight. The material must have a fracture toughness of 5 MPa/m2, have a minimum lifetime of 10, 000 cycles and must not experience brittle fracture. Both single material and hybrid solutions were explored. When further selecting to minimize weight, woods were found to be the best material. Titanium alloy-wood composites were explored to determine the optimal percentage composition of each material.A sandwich panel hybrid of 50% titanium alloy and 50% wood (Ti-Wood) was found to be the optimum material, performing better than the currently used plywood.

Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

Science.gov (United States)

Wananuruksawong, R.; Jinawath, S.; Padipatvuthikul, P.; Wasanapiarnpong, T.

2011-10-01

Silicon nitride (Si3N4) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si3N4 ceramic as a dental core material. The white Si3N4 was prepared by pressureless sintering at relative low sintering temperature of 1650 °C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si3N4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si3N4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (tube furnace between 1000-1200°C. The veneered specimens fired at 1100°C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98×10-6 °C-1, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

Composition of Mineral Produced by Dental Mesenchymal Stem Cells.

Science.gov (United States)

Volponi, A A; Gentleman, E; Fatscher, R; Pang, Y W Y; Gentleman, M M; Sharpe, P T

2015-11-01

Mesenchymal stem cells isolated from different dental tissues have been described to have osteogenic/odontogenic-like differentiation capacity, but little attention has been paid to the biochemical composition of the material that each produces. Here, we used Raman spectroscopy to analyze the mineralized materials produced in vitro by different dental cell populations, and we compared them with the biochemical composition of native dental tissues. We show that different dental stem cell populations produce materials that differ in their mineral and matrix composition and that these differ from those of native dental tissues. In vitro, BCMP (bone chip mass population), SCAP (stem cells from apical papilla), and SHED (stem cells from human-exfoliated deciduous teeth) cells produce a more highly mineralized matrix when compared with that produced by PDL (periodontal ligament), DPA (dental pulp adult), and GF (gingival fibroblast) cells. Principal component analyses of Raman spectra further demonstrated that the crystallinity and carbonate substitution environments in the material produced by each cell type varied, with DPA cells, for example, producing a more carbonate-substituted mineral and with SCAP, SHED, and GF cells creating a less crystalline material when compared with other dental stem cells and native tissues. These variations in mineral composition reveal intrinsic differences in the various cell populations, which may in turn affect their specific clinical applications. © International & American Associations for Dental Research 2015.

Relationship Among Dental Students' Class Lecture Attendance, Use of Online Resources, and Performance.

Science.gov (United States)

Azab, Ehab; Saksena, Yun; Alghanem, Tofool; Midle, Jennifer Bassett; Molgaard, Kathleen; Albright, Susan; Karimbux, Nadeem

2016-04-01

This study aimed to evaluate the relationship among dental students' attendance at class lectures, use of online lecture materials, and performance in didactic courses. The study was conducted with second-year predoctoral students at Tufts University School of Dental Medicine during the fall semester of 2014. Three basic science and three preclinical dental courses were selected for evaluation. Online usage for each participant was collected, and a survey with questions about attendance and online behavior was conducted. The final grade for each participant in each selected course was obtained and matched with his or her online usage and attendance. Out of a total 190 students, 146 (77%) participated. The results showed no significant relationship between students' grades and their class attendance or online usage except for a weak negative relationship between class attendance and online usage for the Epidemiology course (pattendance, online usage, and course grades, most of the students reported that having the online resources in addition to the lectures was helpful.

Prevalence of dental erosion in 12-year-old schoolchildren of Lucknow city

Directory of Open Access Journals (Sweden)

Pooja Sinha

2016-01-01

Full Text Available Introduction: Dental erosion is tooth surface loss caused by chemical processes without bacterial involvement, which can affect children because of various dietary and other lifestyle factors. Aims: The aim of this study was to assess the prevalence of dental erosion in 12-year-old schoolchildren in Lucknow city. Materials and Methods: A total of 212 schoolchildren were selected through multistage cluster random sampling method. A pretested self-administered pro forma was used to record demographic data, medical history, and dietary habits. The clinical examination was done to evaluate dental erosion of children using dental erosion index by O'Sullivan. Descriptive analytical tests were used including distribution of erosion, its extent and severity. The findings were compared across the study participants using Chi-square test. Results: The overall prevalence of dental erosion was 34.12% with no significant sex difference. Dental erosion was significantly related to the frequency of consumption of fruit juices (67.07% followed by carbonated drinks (64.47%. In most of the cases, more than half of their surfaces were diagnosed as affected by erosion (26.25% central incisors, 4.83% lateral incisors. Conclusions: Dental erosion among the study group was found to be 34.12%, providing evidence that dental erosion is becoming a significant problem in Lucknow schoolchildren.

Solid waste production and its management in dental clinics in Gorgan, northern Iran.

Science.gov (United States)

Nabizadeh, R; Faraji, H; Mohammadi, A A

2014-10-01

Waste produced in dental clinics has been the topic of investigations for many years. These waste materials have important health impacts and are hazardous to humans and the environment. To investigating solid waste production and its management in dental clinics in Gorgan, northern Iran. In this cross-sectional study, 45 of 143 public dental practices and 5 of 25 private dental practices were selected and studied. From each clinic, 3 samples were taken and analyzed at the end of successive working days (Tuesday and Wednesday). Samples were manually sorted into 50 components. The measured components were then classified on the basis of their characteristics, hazard potentials, and WHO classification. The total annual amount of dental waste produced in public and private dental practices in Gorgan was 12 015.1 and 3135.0 kg, respectively. Production percentages of infectious, domestic, chemical and pharmaceutical, and toxic waste in public dental practices were 38.4%, 33.7%, 6.6%, and 0.6%, respectively. The percentages for private practices were 8.7%, 10.6%, 1.1%, and 0.1%, respectively. Dental waste management in Gorgan is inadequate; dental waste is not properly segregated, collected, and disposed, as demanded by the WHO. Employees in dentist offices must be trained in correct handling of waste products and the associated risks.

The effect of orthodontic bonding materials on dental plaque accumulation and composition in vitro.

Science.gov (United States)

Badawi, H; Evans, R D; Wilson, M; Ready, D; Noar, J H; Pratten, J

2003-08-01

The aim of this study was to investigate the accumulation and composition of microcosm dental plaque on different orthodontic bonding materials using an in vitro model. Microcosm plaques were grown on discs of a range of bonding materials in a constant depth film fermentor. The biofilms were derived from human saliva and supplied with artificial saliva as a source of nutrients. The number of viable bacteria in the biofilms was determined and the streptococci present were identified to species level. The results showed that there was no significant difference in bacterial accumulation between different bonding materials, however, biofilms grown on materials which were fluoride releasing, did not contain Streptococcus mutans. This in vitro study has shown that the use of fluoride-releasing bonding materials may support the growth of supragingival plaque, which does not contain S. mutans.

Dental image replacement on cone beam computed tomography with three-dimensional optical scanning of a dental cast, occlusal bite, or bite tray impression.

Science.gov (United States)

Kang, S-H; Lee, J-W; Lim, S-H; Kim, Y-H; Kim, M-K

2014-10-01

The goal of the present study was to compare the accuracy of dental image replacement on a cone beam computed tomography (CBCT) image using digital image data from three-dimensional (3D) optical scanning of a dental cast, occlusal bite, and bite tray impression. A Bracket Typodont dental model was used. CBCT of the dental model was performed and the data were converted to stereolithography (STL) format. Three experimental materials, a dental cast, occlusal bite, and bite tray impression, were optically scanned in 3D. STL files converted from the CBCT of the Typodont model and the 3D optical-scanned STL files of the study materials were image-registered. The error range of each methodology was measured and compared with a 3D optical scan of the Typodont. For the three materials, the smallest error observed was 0.099±0.114mm (mean error±standard deviation) for registering the 3D optical scan image of the dental cast onto the CBCT dental image. Although producing a dental cast can be laborious, the study results indicate that it is the preferred method. In addition, an occlusal bite is recommended when bite impression materials are used. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Process Development of Porcelain Ceramic Material with Binder Jetting Process for Dental Applications

Science.gov (United States)

Miyanaji, Hadi; Zhang, Shanshan; Lassell, Austin; Zandinejad, Amirali; Yang, Li

2016-03-01

Custom ceramic structures possess significant potentials in many applications such as dentistry and aerospace where extreme environments are present. Specifically, highly customized geometries with adequate performance are needed for various dental prostheses applications. This paper demonstrates the development of process and post-process parameters for a dental porcelain ceramic material using binder jetting additive manufacturing (AM). Various process parameters such as binder amount, drying power level, drying time and powder spread speed were studied experimentally for their effect on geometrical and mechanical characteristics of green parts. In addition, the effects of sintering and printing parameters on the qualities of the densified ceramic structures were also investigated experimentally. The results provide insights into the process-property relationships for the binder jetting AM process, and some of the challenges of the process that need to be further characterized for the successful adoption of the binder jetting technology in high quality ceramic fabrications are discussed.

Wear of MgO-CaO-SiO2-P2O5-F-Based Glass Ceramics Compared to Selected Dental Ceramics

Directory of Open Access Journals (Sweden)

Jongee Park

2007-01-01

Full Text Available Wear of a glass-ceramic produced through controlled crystallization of a glass in the MgO-CaO-SiO2-P2O5-F system has been evaluated and compared to various commercial dental ceramics including IPS Empress 2, Cergo Pressable Ceramic, Cerco Ceram, and Super porcelain EX-3. Wear tests were performed in accord with the ASTM G99 for wear testing with a pin-on-disk apparatus. The friction coefficient and specific wear rate of the materials investigated were determined at a load of 10 N and at ambient laboratory conditions. Microhardness of the materials was also measured to elucidate the appropriateness of these materials for dental applications.

FACTORS INFLUENCING THE SELECTION OF DENTAL NURSING ...

African Journals Online (AJOL)

drclement

to 85 dental nursing students from 3. Colleges ... products of mixed school. Teaching was the commonest job among 27.1% .... Social Science (SPSS version 15.0) ... Frequency Percent. Educational status. Father. Informal. 6. 7.1. Primary. 10.

Concentration Levels of Particulate Matter of Common Dental Lab Materials in a Military Dental Lab

Science.gov (United States)

2016-05-01

technician.” British Dental Journal 1999, 186:380-381 22 Suvarna SR. “Allergy to methyl methacrylate: a review.” Clinical Dentistry Vol 6, Issue 9...Health Organization , Geneva, Web, 1998. 24 Marquardt W, Seiss M, Hickel R, Reichl FX. “Volatile methacrylates in dental practices” Journal of... International Journal for Quality Research 5 th IQC, May 20 2011:595-602 35 Cimrin A, Nuray K, Canan K, Tertemiz KC. “Pneumoconiosis

Mechanical fatigue degradation of ceramics versus resin composites for dental restorations.

Science.gov (United States)

Belli, Renan; Geinzer, Eva; Muschweck, Anna; Petschelt, Anselm; Lohbauer, Ulrich

2014-04-01

For posterior partial restorations an overlap of indication exists where either ceramic or resin-based composite materials can be successfully applied. The aim of this study was to compare the fatigue resistance of modern dental ceramic materials versus dental resin composites in order to address such conflicts. Bar specimens of five ceramic materials and resin composites were produced according to ISO 4049 and stored for 14 days in distilled water at 37°C. The following ceramic materials were selected for testing: a high-strength zirconium dioxide (e.max ZirCAD, Ivoclar), a machinable lithium disilicate (e.max CAD, Ivoclar), a pressable lithium disilicate ceramic (e-max Press, Ivoclar), a fluorapatite-based glass-ceramic (e.max Ceram, Ivoclar), and a machinable color-graded feldspathic porcelain (Trilux Forte, Vita). The composite materials selected were: an indirect machinable composite (Lava Ultimate, 3M ESPE) and four direct composites with varying filler nature (Clearfil Majesty Posterior, Kuraray; GrandioSO, Voco; Tetric EvoCeram, Ivoclar-Vivadent; and CeramX Duo, Dentsply). Fifteen specimens were tested in water for initial strength (σin) in 4-point bending. Using the same test set-up, the residual flexural fatigue strength (σff) was determined using the staircase approach after 10(4) cycles at 0.5 Hz (n=25). Weibull parameters σ0 and m were calculated for the σin specimens, whereas the σff and strength loss in percentage were obtained from the fatigue experiment. The zirconium oxide ceramic showed the highest σin and σff (768 and 440 MPa, respectively). Although both lithium disilicate ceramics were similar in the static test, the pressable version showed a significantly higher fatigue resistance after cyclic loading. Both the fluorapatite-based and the feldspathic porcelain showed equivalent initial and cyclic fatigue properties. From the composites, the highest filled direct material Clearfil Majesty Posterior showed superior fatigue performance

Dental anomalies in children with cleft lip and palate in Western Australia

Science.gov (United States)

Nicholls, Wendy

2016-01-01

Objective: The purpose of this paper was to describe the prevalence and type of dental anomalies in the primary and permanent dentition in children with a cleft condition at Princess Margaret Hospital in Perth, Western Australia. Materials and Methods: The details of 162 current dental patients extracted from the main dental database through their year of birth for the period 1998–2001 were selected consecutively. Dental records and X-rays were examined by one examiner (WN) and verified by a second examiner (RB) to determine dental development. The mean age of the subjects was 10.8 years with equal numbers of males and females. Subjects were further divided into cleft type; unilateral cleft lip (UCL) and palate, bilateral cleft lip (BCL) and palate, UCL, BCL, and cleft palate. Results: One hundred sixty-two subjects were grouped into 21 categories of anomaly or abnormality. Prevalence rates for the categories were calculated for the overall group and for gender and cleft type. Conclusion: Overall, 94% of patients were found to have at least one dental anomaly, with fifty-six (34%) patients having more than one anomaly or abnormality. PMID:27095907

Bridging the gap in 1(st) year dental material curriculum: A 3 year randomized cross over trial.

Science.gov (United States)

Gali, Sivaranjani; Shetty, Vibha; Murthy, N S; Marimuthu, P

2015-01-01

Case-oriented small group discussions (COSGDs) can help students to correlate and integrate the basic science of dental materials into clinical application. We used COSGDs along with didactic lectures in dental material curriculum and hypothesized that case-oriented group discussions would be more effective than traditional lecture alone in terms of performance of students, student perception on the above two teaching methodologies and the feasibility in classes of 2010, 2011 and 2012. A total of 170 students were taught using both COSGD and didactic lecture in a randomized controlled crossover trial design. Their performance was assessed through multiple-choice questions (MCQs) as part of the formative assessment, and their perception was assessed through Likert scale questionnaire. The mean difference in the scores between case-oriented group discussions with lecture and didactic lecture showed significant difference only in few topics. Around 94-96% of students perceived COSGD with didactic lecture help them understand theory better; 76-92% of students feel more comfortable asking questions in a group discussion; 89-98% of students feel such discussions motivate them and 91-100% of students agree that discussions make the subject interesting in the respective years of 2010, 2011 and 2012. Effectiveness of COSGD in terms of scores through MCQs is comparable to traditional lecture. However, most of the students perceive COSGD help them understand the theory better; co-relate clinically; more motivating and interesting than a traditional lecture. Feasibility in institution needs more time and resources to conduct COSGD within the dental material curriculum.

Selective ablation of dental calculus with a frequency-doubled Alexandrite laser

Science.gov (United States)

Rechmann, Peter; Hennig, Thomas

1996-01-01

The aim of the study was the selective removal of dental calculus by means of pulsed lasers. In a first approach the optical characteristics of subgingival calculus were calculated using fluorescence emission spectroscopy (excitation laser: N2-laser, wavelength 337 nm, pulse duration 4 ns). Subgingival calculus seems to absorb highly in the ultraviolet spectral region up to 420 nm. According to these measurements a frequency doubled Alexandrite-laser (wavelength 377 nm, pulse duration 100 ns, repetition rate 110 Hz) was used to irradiate calculus located on enamel, at the cementum enamel junction and on the root surface (located on dentin or on cementum). Irradiation was performed perpendicular to the root surface with a laser fluence of 1 Jcm-2. During the irradiation procedure an effective water cooling-system was engaged. Histological investigations were done on undecalcified sections. As a result, engaging low fluences allows a fast and strictly selective removal of subgingival calculus. Even more the investigations revealed that supragingival calculus can be removed in a strictly selective manner engaging a frequency doubled Alexandrite-laser. No adverse side effects to the surrounding tissues could be found.

Selective removal of esthetic composite restorations with spectral guided laser ablation

Science.gov (United States)

Yi, Ivana; Chan, Kenneth H.; Tsuji, Grant H.; Staninec, Michal; Darling, Cynthia L.; Fried, Daniel

2016-02-01

Dental composites are used for a wide range of applications such as fillings for cavities, adhesives for orthodontic brackets, and closure of gaps (diastemas) between teeth by esthetic bonding. Anterior restorations are used to replace missing, diseased and unsightly tooth structure for both appearance and function. When these restorations must be replaced, they are difficult to remove mechanically without causing excessive removal or damage to enamel because dental composites are color matched to teeth. Previous studies have shown that CO2 lasers have high ablation selectivity and are well suited for removal of composite on occlusal surfaces while minimizing healthy tissue loss. A spectral feedback guidance system may be used to discriminate between dental composite and dental hard tissue for selective ablation of composite material. The removal of composite restorations filling diastemas is more challenging due to the esthetic concern for anterior teeth. The objective of this study is to determine if composite spanning a diastema between anterior teeth can be removed by spectral guided laser ablation at clinically relevant rates with minimal damage to peripheral healthy tissue and with higher selectivity than a high speed dental handpiece.

Biological Effects of Provisional Resin Materials on Human Dental Pulp Stem Cells.

Science.gov (United States)

Jun, S-K; Mahapatra, C; Lee, H-H; Kim, H-W; Lee, J-H

This study investigated the in vitro cytotoxicity as well as the proinflammatory cytokine expression of provisional resin materials on primary cultured human dental pulp stem cells (hDPSCs). Five commercially available provisional resin materials were chosen (SNAP [SN], Luxatemp [LT], Jet [JE], Revotek LC [RL], and Vipi block [VB]). Eluates that were either polymerizing or already set were added to hDPSCs under serially diluted conditions divided into three different setting times (25% set, 50% set, and 100% set) and incubated for 24 hours with 2× concentrated culture media. Cell cytotoxicity tests were performed by LDH assay and live and dead confocal microscope images. The expression of proinflammatory cytokines in SN and VB was measured using cytokine antibody arrays. Data were analyzed using repeated measures analysis of variance (ANOVA) or ANOVA followed by the Tukey post hoc test at a significance level of pprovisional resin materials during polymerization (SN, LT, and JE) were cytotoxic to hDPSCs and may adversely affect pulp tissue.

Research in dental practice: a 'SWOT' analysis.

Science.gov (United States)

Burke, F J T; Crisp, R J; McCord, J F

2002-03-01

Most dental treatment, in most countries, is carried out in general dental practice. There is therefore a potential wealth of research material, although clinical evaluations have generally been carried out on hospital-based patients. Many types of research, such as clinical evaluations and assessments of new materials, may be appropriate to dental practice. Principal problems are that dental practices are established to treat patients efficiently and to provide an income for the staff of the practice. Time spent on research therefore cannot be used for patient treatment, so there are cost implications. Critics of practice-based research have commented on the lack of calibration of operative diagnoses and other variables; however, this variability is the stuff of dental practice, the real-world situation. Many of the difficulties in carrying out research in dental practice may be overcome. For the enlightened, it may be possible to turn observations based on the volume of treatment carried out in practice into robust, clinically related and relevant research projects based in the real world of dental practice.

The effect of bleaching agents on the microhardness of dental aesthetic restorative materials.

Science.gov (United States)

Türker, S B; Biskin, T

2002-07-01

This study investigated the effects of three home bleaching agents on the microhardness of various dental aesthetic restorative materials. The restorative materials were: feldspatic porcelain, microfilled composite resin and light-cured modified glass-ionomer cement and the bleaching agents Nite-White (16% carbamide peroxide), Opalescence (10% carbamide peroxide and carbapol jel) and Rembrandt (10% carbamide peroxide jel). A total of 90 restorative material samples were prepared 1 cm diameter and 6 mm thick and kept in distilled water for 24 h before commencing bleaching which was carried out for 8 h day-1 for 4 weeks. Microhardness measurements were then made using a Tukon tester. Statistically significant differences with respect to unbleached controls were found only for the feldspatic porcelain and microfilled composite resins (P light cured modified glass-ionomer cement. For the composite resin, whereas Nite-White increased its microhardness, the other bleaching agents decreased it. There were no significant differences between the bleaching agents for any of the restorative materials.

Surface deterioration of dental materials after simulated toothbrushing in relation to brushing time and load.

Science.gov (United States)

Heintze, S D; Forjanic, M; Ohmiti, K; Rousson, V

2010-04-01

(1) To evaluate the changes in surface roughness and gloss after simulated toothbrushing of 9 composite materials and 2 ceramic materials in relation to brushing time and load in vitro; (2) to assess the relationship between surface gloss and surface roughness. Eight flat specimens of composite materials (microfilled: Adoro, Filtek Supreme, Heliomolar; microhybrid: Four Seasons, Tetric EvoCeram; hybrid: Compoglass F, Targis, Tetric Ceram; macrohybrid: Grandio), two ceramic materials (IPS d.SIGN and IPS Empress polished) were fabricated according to the manufacturer's instructions and optimally polished with up to 4000 grit SiC. The specimens were subjected to a toothbrushing (TB) simulation device (Willytec) with rotating movements, toothpaste slurry and at three different loads (100g/250g/350g). At hourly intervals from 1h to 10h TB, mean surface roughness Ra was measured with an optical sensor and the surface gloss (Gl) with a glossmeter. Statistical analysis was performed for log-transformed Ra data applying two-way ANOVA to evaluate the interaction between load and material and load and brushing time. There was a significant interaction between material and load as well as between load and brushing time (pgloss was the parameter which discriminated best between the materials, followed by mean surface roughness Ra. There was a strong correlation between surface gloss and surface roughness for all the materials except the ceramics. The evaluation of the deterioration curves of individual specimens revealed a more or less synchronous course suspecting hinting specific external conditions and not showing the true variability in relation to the tested material. The surface roughness and gloss of dental materials changes with brushing time and load and thus results in different material rankings. Apart from Grandio, the hybrid composite resins were more prone to surface changes than microfilled composites. The deterioration potential of a composite material can be

New ion selective materials. Application to the selective extraction of caesium

International Nuclear Information System (INIS)

Favre-Reguillon, Alain

1996-01-01

This research thesis addresses the synthesis and assessment of ion selective materials. The first part reports the development of a general method of assessment of ion selective materials. In the second part, the author describes different methods used to insolubilize macro-cycles on hydrophilic polymers. The obtained polyurethanes are synthesised. These hydrophilic polymers display interesting complexing properties and selectivities with respect to cations of alkali metals. Then the author addresses the improvement of selectivity with respect to caesium of ion exchange resorcinol-formaldehyde resins. Different factors affecting selectivity are identified, and the concept of molecular print is used to study the improvement of selectivity. The effect of macro-cyclic structures on phenolic resins with respect to caesium is highlighted [fr

Urea dimethacrylates functionalized with bisphosphonate/bisphosphonic acid for improved dental materials

OpenAIRE

Güven, Melek Naz; Guven, Melek Naz; Akyol, Ece; Duman, Fatma Demir; Acar, Havva Yağcı; Acar, Havva Yagci; Karahan, Özlem; Karahan, Ozlem; Avcı, Duygu; Avci, Duygu

2017-01-01

Incorporation of bisphosphonate/bisphosphonic acid groups in dental monomer structures should increase interaction of these monomers with dental tissue as these groups have strong affinity for hydroxyapatite. Therefore, new urea dimethacrylates functionalized with bisphosphonate (1a, 1b) and bisphosphonic acid (2a, 2b) groups are synthesized and evaluated for dental applications. Monomers 1a and 1b are synthesized from 2isocyanatoethyl methacrylate (IEM) and two bisphosphonated amines (BPA1 a...

Solid Waste Production and Its Management in Dental Clinics in Gorgan, Northern Iran

Directory of Open Access Journals (Sweden)

R Nabizadeh

2014-09-01

Full Text Available Background: Waste produced in dental clinics has been the topic of investigations for many years. These waste materials have important health impacts and are hazardous to humans and the environment. Objective: To investigating solid waste production and its management in dental clinics in Gorgan, northern Iran. Methods: In this cross-sectional study, 45 of 143 public dental practices and 5 of 25 private dental practices were selected and studied. From each clinic, 3 samples were taken and analyzed at the end of successive working days (Tuesday and Wednesday. Samples were manually sorted into 50 components. The measured components were then classified on the basis of their characteristics, hazard potentials, and WHO classification. Results: The total annual amount of dental waste produced in public and private dental practices in Gorgan was 12 015.1 and 3135.0 kg, respectively. Production percentages of infectious, domestic, chemical and pharmaceutical, and toxic waste in public dental practices were 38.4%, 33.7%, 6.6%, and 0.6%, respectively. The percentages for private practices were 8.7%, 10.6%, 1.1%, and 0.1%, respectively. Conclusion: Dental waste management in Gorgan is inadequate; dental waste is not properly segregated, collected, and disposed, as demanded by the WHO. Employees in dentist offices must be trained in correct handling of waste products and the associated risks.

Resin-composite blocks for dental CAD/CAM applications.

Science.gov (United States)

Ruse, N D; Sadoun, M J

2014-12-01

Advances in digital impression technology and manufacturing processes have led to a dramatic paradigm shift in dentistry and to the widespread use of computer-aided design/computer-aided manufacturing (CAD/CAM) in the fabrication of indirect dental restorations. Research and development in materials suitable for CAD/CAM applications are currently the most active field in dental materials. Two classes of materials are used in the production of CAD/CAM restorations: glass-ceramics/ceramics and resin composites. While glass-ceramics/ceramics have overall superior mechanical and esthetic properties, resin-composite materials may offer significant advantages related to their machinability and intra-oral reparability. This review summarizes recent developments in resin-composite materials for CAD/CAM applications, focusing on both commercial and experimental materials. © International & American Associations for Dental Research.

A review of the strength properties of dental ceramics.

Science.gov (United States)

Hondrum, S O

1992-06-01

New ceramic materials for restorative dentistry have been developed and introduced in recent years. This article reviews advantages and disadvantages of dental ceramics, concentrating on strength properties. Included are factors affecting the strength of dental ceramic materials and the most common mechanisms for increasing the strength of dental ceramics. The properties of presently available materials such as dispersion-strengthened ceramics, cast ceramics, and foil-reinforced materials are discussed. Current research efforts to improve the fracture resistance of ceramic restorative materials are reviewed. A description of methods to evaluate the strength of ceramics is included, as a caution concerning the interpretation of strength data reported in the literature.

Surgical stent for dental implant using cone beam CT images

International Nuclear Information System (INIS)

Choi, Hyung Soo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan

2010-01-01

The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

Paraclinical Effects of Miswak Extract on Dental Plaque

Directory of Open Access Journals (Sweden)

Hamid Reza Poureslami

2007-01-01

Full Text Available Introduction: The Persian toothbrush tree or Miswak (Salvadora Persica L. has been used as a brushing stick for more than 1,300 years. Pharmacological studies indicated antibacterial and antiinflammatory activities of Miswak extract. The present study was performed to determine antibacterial effects of Miswak extract.Material and Methods: The present experimental research involved three in vitro studies including: 1 in vitro testing of the effect of Miswak extract on selected bacteria; 2 comparing the paraclinical effects of Iranian toothpaste containing Miswak extract and placebo toothpaste on dental plaque; and 3 comparing the antibacterial effect of Iranian toothpaste with Swiss toothpaste(Quail Miswak on dental plaque. The disc diffusion method was used to test bacterial sensitivity of toothpastes. Data were analyzed by paired t-test and ANOVA.Results: In the first study, Miswak extract inhibited the growth of some dental plaque bacteria. In the second study, antibacterial effect of the herbal toothpaste was significantly greater than that of the placebo (P =0.002. In the third study, four samples of dental plaque bacteria were used and there was no difference between the antibacterial effects of Swiss and Iranian herbal toothpastes (P =0.66.Conclusion: Due to antimicrobial effects of Miswak extract, its use in mouth rinses and toothpastes is highly recommended.

Chronic Cutaneous Draining Sinus of Dental Origin

African Journals Online (AJOL)

Endodontics, JSS Dental College and Hospital, Mysore, Karnataka, India. Abstract ... Keywords: Dental fistula, Localized drug delivery, Root canal treatment. Access this article ... combination of intra-canal irrigants was selected. Hypochlorite.

The materials selection in ITER and the first materials workshop

International Nuclear Information System (INIS)

Matera, R.; Barabash, V.; Kalinin, G.; Tanaka, S.

1998-01-01

The selection of materials and joining technologies to be used in ITER is a trade-off between multiple and often conflicting requirements derived from the unique features of the fusion environment. Materials selection must encompass a total engineering approach, by considering not only physical and mechanical properties, but also the components' manufacturing, their maintainability and reliability, and, finally, how they can be recycled or disposed of at the end of machine operation

Systemic Assessment of Patients Undergoing Dental Implant ...

African Journals Online (AJOL)

Background: Procedure‑related and patient‑related factors influence the prognosis of dental implants to a major extent. Hence, we aimed to evaluate and analyze various systemic factors in patients receiving dental implants. Materials and Methods: Fifty‑one patients were included in the study, in which a total of 110 dental ...

Dental amalgam: effects of alloy/mercury mixing ratio, uses and waste management

International Nuclear Information System (INIS)

Kefi, I.; Maria, A.; Sana, J.; Afreen, J.; Adel, S.; Iftikhar, A.; Yawer, A.; Kaleem, M.

2011-01-01

Background: Silver dental amalgam is one of the oldest filling materials used in dentistry. The American Dental Association (ADA) has estimated that billions of amalgam restorations have been placed in patients in the last 150 years. Due to the presence of mercury and mishandling during the filling make it more controversial. The objective of this study was to conduct a survey of the use of different brands and to assess any deviations in practice from the hand mixing manual method of elemental mercury and alloy in a pestle/mortar and encapsulated form. Methods: A questionnaire was sent to 250 of randomly selected dental practitioner in various localities of Karachi. Data was analysed to record the specified brands used along with their powder/liquid (P/L) ratio and the different methods for disposing off mercury in this study. Results: The most commonly used form of dispensing method was hand mixing (57%) and only 30% of the dentists followed the manufacturer instruction for hand mixing ratio. Eighty-seven percent of dental amalgam restoration was performed and 13% removed by the dentist per month and the method of disposing the amalgam wastage that 55%, 25%, and 20% dentists were used the sink, bin and other methods respectively in their dental clinics. Conclusion: Amalgam restoration is still popular filling material in the posterior region of the mouth but we need to create awareness among the dentists who do not follow the ADA specifications. (author)

Dental fear and caries in 6-12 year old children in Greece. Determination of dental fear cut-off points.

Science.gov (United States)

Boka, V; Arapostathis, K; Karagiannis, V; Kotsanos, N; van Loveren, C; Veerkamp, J

2017-03-01

To present: the normative data on dental fear and caries status; the dental fear cut-off points of young children in the city of Thessaloniki, Greece. Study Design: This is a cross-sectional study with two independent study groups. A first representative sample consisted of 1484 children from 15 primary public schools of Thessaloniki. A second sample consisted of 195 randomly selected age-matched children, all patients of the Postgraduate Paediatric Dental Clinic of Aristotle University of Thessaloniki. First sample: In order to select data on dental fear and caries, dental examination took place in the classroom with disposable mirrors and a penlight. All the children completed the Dental Subscale of the Children's Fear Survey Schedule (CFSS-DS). Second sample: In order to define the cut-off points of the CFSS-DS, dental treatment of the 195 children was performed at the University Clinic. Children⁁s dental fear was assessed using the CFSS-DS and their behaviour during dental treatment was observed by one calibrated examiner using the Venham scale. Statistical analysis of the data was performed with IBM SPSS Statistics 20 at a statistical significance level of fear. Mean differences between boys and girls were not significant. Caries was not correlated with dental fear. Second sample: CFSS-DSfear', scores 33-37 as 'borderline' and scores > 37 as 'dental fear'. In the first sample, 84.6% of the children did not suffer from dental fear (CFSS-DSfear was correlated to age and not to caries and gender. The dental fear cut-off point for the CFSS-DS was estimated at 37 for 6-12 year old children (33-37 borderlines).

Human Cadaver Material in Preclinical Oral Surgery.

Science.gov (United States)

Barber, H. Dexter; And Others

1993-01-01

A University of Michigan dental school curriculum for oral surgery that uses human cadaver heads is described. Selection, preparation, and laboratory use of the materials are outlined. Faculty and students have received the sequence well and found it prepared them for clinical rotation. (MSE)

Organisational aspects of dental practices: do dental students think like patients or like general dental practitioners?

Science.gov (United States)

Sonneveld, R E; Brands, W G; Bronkhorst, E M; Welie, J V M; Truin, G J

2013-02-01

In view of transparency in health care, the widespread desire for more patient-centred care, and in an attempt to facilitate educational programmes that effectively respond to these changes, two research questions are formulated: (i) How do dental students rate the importance of various organisational aspects of dental practices compared with dental patients and general dental practitioners (GDPs), and what prescripts, defined as specific operational responsibilities of GDPs in these matters, do dental students propose? and (ii) In doing so, do students resemble patients or GDPs? In two survey studies, dental students (n = 198), patients (n = 3127) and GDPs (n = 303) were asked to rate by questionnaire the importance of 41 organisational aspects of a general dental practice and proposed specific operational responsibilities ('prescripts'). Seven of 41 aspects were rated as important by the majority of the students. Although in a different rank order, three aspects were predominantly selected by all three groups: continuing education, accessibility by telephone and Dutch-speaking GDP. For most aspects, significant differences were found between the prescripts proposed by students and those proposed by patients, and few differences were found between students and GDPs. The findings do not permit the general conclusion that the views of dental students resemble those of patients or GPDs. Looking at the overall rank order, the three respondent groups showed a great resemblance although significant differences were found for specific aspects. With regard to the proposed prescripts, students showed realistic views and the majority wants to participate in continuing education and work with protocols and guidelines. In this, they tend to resemble GDPs more than they resemble patients. © 2012 John Wiley & Sons A/S.

Dental Chairside Technique. Student's Manual.

Science.gov (United States)

Apfel, Maura; Weaver, Trudy Karlene

This manual is part of a series dealing with skills and information needed by students in dental assisting. The individualized student materials are suitable for classroom, laboratory, or cooperative training programs. This student manual contains four units covering the following topics: local anesthesia; dental office emergencies; oral hygiene;…

Nonlinear finite element analyses: advances and challenges in dental applications.

Science.gov (United States)

Wakabayashi, N; Ona, M; Suzuki, T; Igarashi, Y

2008-07-01

To discuss the development and current status of application of nonlinear finite element method (FEM) in dentistry. The literature was searched for original research articles with keywords such as nonlinear, finite element analysis, and tooth/dental/implant. References were selected manually or searched from the PUBMED and MEDLINE databases through November 2007. The nonlinear problems analyzed in FEM studies were reviewed and categorized into: (A) nonlinear simulations of the periodontal ligament (PDL), (B) plastic and viscoelastic behaviors of dental materials, (C) contact phenomena in tooth-to-tooth contact, (D) contact phenomena within prosthodontic structures, and (E) interfacial mechanics between the tooth and the restoration. The FEM in dentistry recently focused on simulation of realistic intra-oral conditions such as the nonlinear stress-strain relationship in the periodontal tissues and the contact phenomena in teeth, which could hardly be solved by the linear static model. The definition of contact area critically affects the reliability of the contact analyses, especially for implant-abutment complexes. To predict the failure risk of a bonded tooth-restoration interface, it is essential to assess the normal and shear stresses relative to the interface. The inclusion of viscoelasticity and plastic deformation to the program to account for the time-dependent, thermal sensitive, and largely deformable nature of dental materials would enhance its application. Further improvement of the nonlinear FEM solutions should be encouraged to widen the range of applications in dental and oral health science.

Purified Human Dental Pulp Stem Cells Promote Osteogenic Regeneration.

Science.gov (United States)

Yasui, T; Mabuchi, Y; Toriumi, H; Ebine, T; Niibe, K; Houlihan, D D; Morikawa, S; Onizawa, K; Kawana, H; Akazawa, C; Suzuki, N; Nakagawa, T; Okano, H; Matsuzaki, Y

2016-02-01

Human dental pulp stem/progenitor cells (hDPSCs) are attractive candidates for regenerative therapy because they can be easily expanded to generate colony-forming unit-fibroblasts (CFU-Fs) on plastic and the large cell numbers required for transplantation. However, isolation based on adherence to plastic inevitably changes the surface marker expression and biological properties of the cells. Consequently, little is currently known about the original phenotypes of tissue precursor cells that give rise to plastic-adherent CFU-Fs. To better understand the in vivo functions and translational therapeutic potential of hDPSCs and other stem cells, selective cell markers must be identified in the progenitor cells. Here, we identified a dental pulp tissue-specific cell population based on the expression profiles of 2 cell-surface markers LNGFR (CD271) and THY-1 (CD90). Prospectively isolated, dental pulp-derived LNGFR(Low+)THY-1(High+) cells represent a highly enriched population of clonogenic cells--notably, the isolated cells exhibited long-term proliferation and multilineage differentiation potential in vitro. The cells also expressed known mesenchymal cell markers and promoted new bone formation to heal critical-size calvarial defects in vivo. These findings suggest that LNGFR(Low+)THY-1(High+) dental pulp-derived cells provide an excellent source of material for bone regenerative strategies. © International & American Associations for Dental Research 2015.

Investigation into the optimum beam shape and fluence for selective ablation of dental calculus at lambda = 400 nm.

Science.gov (United States)

Schoenly, Joshua E; Seka, Wolf; Rechmann, Peter

2010-01-01

A frequency-doubled Ti:sapphire laser is shown to selectively ablate dental calculus. The optimal transverse shape of the laser beam, including its variability under water-cooling, is determined for selective ablation of dental calculus. Intensity profiles under various water-cooling conditions were optically observed. The 400-nm laser was coupled into a multimode optical fiber using an f = 2.5-cm lens and light-shaping diffuser. Water-cooling was supplied coaxially around the fiber. Five human tooth samples (four with calculus and one pristine) were irradiated perpendicular to the tooth surface while the tooth was moved back and forth at 0.3 mm/second, varying between 20 and 180 iterations. The teeth were imaged before and after irradiation using light microscopy with a flashing blue light-emitting diode (LED). An environmental scanning electron microscope imaged each tooth after irradiation. High-order super-Gaussian intensity profiles are observed at the output of a fiber coiled around a 4-in. diameter drum. Super-Gaussian beams have a more-homogenous fluence distribution than Gaussian beams and have a higher energy efficiency for selective ablation. Coaxial water-cooling does not noticeably distort the intensity distribution within 1 mm from the optical fiber. In contrast, lasers focused to a Gaussian cross section (Calculus is preferentially ablated at high fluences (> or =2 J/cm(2)); below this fluence, stalling occurs because of photo-bleaching of the calculus. Healthy dental hard tissue is not removed at fluences calculus with a frequency-doubled Ti:sapphire laser. Fluences over 2 J/cm(2) are required to remove calculus efficiently since photo-bleaching stalls calculus removal below that value.

Quantity and quality of solid wastes produced in dental offices of babol city

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Abdoliman Amouei

2016-09-01

Full Text Available Introduction: Dental wastes due to having bacterial disease-causing agents and toxic chemicals are categorized in hazardous wastes. The aim of this study was to evaluate the quantity and composition of dental waste produced by general and specialized dental offices in babol city. Materials &Methods: From all dental offices (170 and 40 dental offices were related to general and specialized respectively in Babol city, 20 general and 5 specialized offices were randomly selected. Waste samples were collected three times a week (Sunday, Monday and Tuesday, 50 sub-groups were separated and weighted by a digital scale with accuracy of 0.01 gram. The data were presented by excel and word software in figures and tables. Results: The total wastes of general and specialized offices were 11829 and 2831.5 kg/year, respectively. The percentages of domestic-type, infectious, pharmaceutical and toxic wastes in general dental offices were 52.5%, 42.5%, 4.7% and 0.3%; and in specialized offices were 42.5%, 50%, 7% and 0.5%, respectively. Most components in a variety of dental waste included plastic, paper, plaster molds, glass and metal. Conclusion: Due to the large contents of plastic, paper, plaster molds, glass and metals in domestic- type and infectious wastes produced in the general and specialized dental offices, it is necessary to manage the wastes and their separation and recycling in source place.

An overview of dental radiology: a primer on dental radiology

International Nuclear Information System (INIS)

Manny, E.F.; Carlson, K.C.; McClean, P.M.; Rachlin, J.A.; Segal, P.

1980-01-01

To provide medical and scientific background on certain selected technologies generally considered to be of particular significance, the National Center for Health Care Technology (NCHCT) has commissioned a series of overview papers. This is one of several projects entered into jointly by the Bureau of Radiological Health (BRH) and NCHCT relating to the use of radiation for health care. Dental radiation protection has been a long-time interest of BRH. Both past and on-going efforts to minimize population radiation exposure from electronic products have included specific action programs directed at minimizing unnecessary radiation exposure to the population from dental radiology. Current efforts in quality assurance and referral criteria are two aspects of NCHCT's own assessment of this technology which are described within the larger picture presented in this overview. The issues considered in this document go beyond the radiation exposure aspects of dental x-ray procedures. To be responsive to the informational needs of NCHCT, the assessment includes various other factors that influence the practice of dental radiology. It is hoped this analysis will serve as the basis for planning and conducting future programs to improve the practice of dental radiology

Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

International Nuclear Information System (INIS)

Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T; Padipatvuthikul, P

2011-01-01

Silicon nitride (Si 3 N 4 ) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si 3 N 4 ceramic as a dental core material. The white Si 3 N 4 was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si 3 N 4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si 3 N 4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder ( 2 O 3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si 3 N 4 specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10 -6 deg. C -1 , rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

Regenerative medicine in dental and oral tissues: Dental pulp mesenchymal stem cell

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Janti Sudiono

2017-08-01

Full Text Available Background. Regenerative medicine is a new therapeutic modality using cell, stem cell and tissue engineering technologies. Purpose. To describe the regenerative capacity of dental pulp mesenchymal stem cell. Review. In dentistry, stem cell and tissue engineering technologies develop incredibly and attract great interest, due to the capacity to facilitate innovation in dental material and regeneration of dental and oral tissues. Mesenchymal stem cells derived from dental pulp, periodontal ligament and dental follicle, can be isolated, cultured and differentiated into various cells, so that can be useful for regeneration of dental, nerves, periodontal and bone tissues. Tissue engineering is a technology in reconstructive biology, which utilizes mechanical, cellular, or biological mediators to facilitate regeneration or reconstruction of a particular tissue. The multipotency, high proliferation rates and accessibility, make dental pulp as an attractive source of mesenchymal stem cells for tissue regeneration. Revitalized dental pulp and continued root development is the focus of regenerative endodontic while biological techniques that can restore lost alveolar bone, periodontal ligament, and root cementum is the focus of regenerative periodontic. Conclucion. Dentin-derived morphogens such as BMP are known to be involved in the regulation of odontogenesis. The multipotency and angiogenic capacity of DPSCs as the regenerative capacity of human dentin / pulp complex indicated that dental pulp may contain progenitors that are responsible for dentin repair. The human periodontal ligament is a viable alternative source for possible primitive precursors to be used in stem cell therapy.

Dental occlusion and temporomandibular disorders.

Science.gov (United States)

Stone, J Caitlin; Hannah, Andrew; Nagar, Nathan

2017-10-27

Data sourcesMedline, Scopus and Google Scholar.Study selectionTwo reviewers selected studies independently. English language clinical studies assessing the association between temporomandibular disorders (TMD) and features of dental occlusion were considered.Data extraction and synthesisStudy quality was assessed based on the Newcastle-Ottawa Scale (NOS) and a narrative synthesis was presented.ResultsIn all 25 studies (17 case-control, eight comparative) were included. Overall there was a high variability between occlusal features and TMD diagnosis. Findings were consistent with a lack of clinically relevant association between TMD and dental occlusion. Only two studies were associated with TMD in the majority (≥50%) of single variable analyses in patient populations. Only mediotrusive interferences are associated with TMD in the majority of multiple variable analyses.ConclusionsThe findings support the absence of a disease-specific association, there is no ground to hypothesise a major role for dental occlusion in the pathophysiology of TMDs. Dental clinicians are thus encouraged to move forward and abandon the old-fashioned gnathological paradig.

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions.

Science.gov (United States)

Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin; Hwang, Hyeon-Shik

2016-05-01

To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken.

Toxicity testing of restorative dental materials using brine shrimp larvae (Artemia salina).

Science.gov (United States)

Milhem, Manar M; Al-Hiyasat, Ahmad S; Darmani, Homa

2008-01-01

This study investigated the effect of extracts of different composites, glass ionomer cement (GIC)s and compomers on the viability of brine shrimp larvae. Ethanolic extracts of four dental composites (Z-100; Solitaire 2; Filtek P60 and Synergy), a conventional GIC (Ketac-Fil), a resin-modified glass ionomer cement (Vitremer), two compomers (F2000; Dyract AP), and a flowable compomer (Dyract Flow) were prepared from each material. Following evaporation of the ethanol, the extracts were resuspended in distilled water, which was then used to test the effects on the viability of brine shrimp larvae. For the composites, the extract of Synergy was the least toxic (88% viability) followed by the extracts of Solitaire 2, Z100 and P60 (75%, 67.5% and 50% viability, respectively). One-way ANOVA revealed highly significant differences between the resin composite materials (plarvae for the extracts of Ketac-Fil, and Vitremer were 32.3%, and 37.0%, respectively. One-way ANOVA revealed highly significant differences between the groups of materials (pshrimp larvae followed by GICs and then composites.

A retrospective comparison of dental treatment under general ...

African Journals Online (AJOL)

Purpose: The purpose of this study is to determine the properties of the dental procedures performed on children with dental problems under general anesthesia and compared between the patterns of dental treatment provided for intellectual disability and non.cooperate healthy child. Materials and Methods: In this ...

The Management of Dental Waste in Dental Offices and Clinics in Shiraz, Southern Iran

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M Danaei

2014-01-01

Full Text Available Background: Dental waste can be hazardous to humans and the environment. Objective: To determine the current status of dental waste management in private and public dental clinics and private dental offices in Shiraz, southern Iran. Methods: This cross-sectional study was conducted at the Shiraz University of Medical Sciences from February through June 2013. A stratified random sampling method was used to study 86 private offices, 14 private clinics and 10 public clinics. Types of waste studied included mercury and amalgam, lead foil packets, sharps, infectious tissues and fluids, pharmaceuticals and domestic waste materials. Compliance with established standards by the monitored dental offices and clinics and public clinics were compared. Results: 89.1% of dental offices and clinics disposed their infectious waste with domestic waste. Only 60% of centers used standard method for sharps disposal. None of the dental centers disposed their pharmaceutical waste and x-ray fixer waste by standard methods. Less than 10% of centers recycled the amalgam and lead foil pockets waste to the manufacture. Conclusion: Government agencies should establish monitoring programs for all dental offices and clinics to identify noncompliant activity and enforce recommended regulations.

Complex layered dental restorations: Are they recognizable and do they survive extreme conditions?

Science.gov (United States)

Soon, Alistair S; Bush, Mary A; Bush, Peter J

2015-09-01

Recent research has shown that restorative dental materials can be recognized by microscopy and elemental analysis (scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray fluorescence; SEM/EDS and XRF) and that this is possible even in extreme conditions, such as cremation. These analytical methods and databases of dental materials properties have proven useful in DVI (disaster victim identification) of a commercial plane crash in 2009, and in a number of other victim identification cases. Dental materials appear on the market with ever expanding frequency. With their advent, newer methods of restoration have been proposed and adopted in the dental office. Methods might include placing multiple layers of dental materials, where they have different properties including adhesion, viscosity, or working time. These different dental materials include filled adhesives, flowable resins, glass ionomer cements, composite resins, liners and sealants. With possible combinations of different materials in these restorations, the forensic odontologist is now confronted with a new difficulty; how to recognize each individual material. The question might be posed if it is even possible to perform this task. Furthermore, an odontologist might be called upon to identify a victim under difficult circumstances, such as when presented with fragmented or incinerated remains. In these circumstances the ability to identify specific dental materials could assist in the identification of the deceased. Key to use of this information is whether these new materials and methods are detailed in the dental chart. Visual or radiographic inspection may not reveal the presence of a restoration, let alone the possible complex nature of that restoration. This study demonstrates another scientific method in forensic dental identification. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Dental tissue as a thermoluminescence dosimetry dosimeter

International Nuclear Information System (INIS)

Solaimani, F.; Zahmatkesh, M.H.; Akhlaghpoor, Sh.

2003-01-01

Background: Thermoluminescence dosimetry is one of the dosimetry procedures used widely as routine and personal dosimeters. In order to extend this kind of dosimeters, dental tissue has been examined and was found promising as a Thermoluminescence Dosimetry dosimeter. Materials and Methods: In this study, 70 health teeth were collected. The only criterion, wich was considered for selection of the teeth, was the healthiness of them regardless of age and gender of the donors. All collected samples were washed and cleaned and milled uniformly. The final powder had a uniform grain size between 100-300 micrometer. The sample was divided into four groups. Group A and B were used for measurement of density and investigation of variation of thermoluminescent characteristics with temperature respectively. Groups C and D were used for investigation of variation of thermoluminescent intensity with dose and fading of this intensity with time. In all cases the results obtained with dental tissue were compared to a standard LiF, thermoluminescence dosimetry dosimeter. Results: It was found that, average density of the dental tissue was 1.570 g/cm 3 , which is comparable to density of LiF, which is 1.612g/cm 3 . It was also concluded that the range of 0-300 d ig C , dental tissue has a simple curve with two specific peaks at 140 and 25 d ig C respectively. The experiment also showed that, the variation of relative intensity versus dose is linear in the range of 0.04-0.1 Gy. The fading rate of dental tissue is higher than LiF but still in the acceptable range (14% per month in compare to 5.2% per month). Conclusion: Dental tissue as a natural dosimeter is comparable with Thermoluminescence Dosimetry and can be used in accidental events with a good approximation

Caries dental en escolares del Distrito Federal Dental caries in school children in Mexico City

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MARÍA ESTHER IRIGOYEN-CAMACHO

1997-03-01

Full Text Available Objetivo. Presentar las estimaciones de la prevalencia y la severidad de caries dental, así como las necesidades de tratamiento de la población escolar del Distrito Federal examinada en la encuesta de caries dental que se llevó a cabo en 1988 con la finalidad de obtener datos basales sobre caries en los escolares al inicio del Programa Nacional de Fluoruración de la Sal en México. Material y métodos. La población de estudio fue seleccionada empleando un marco muestral basado en el listado de las escuelas primarias y los jardines de niños registrados por la Secretaría de Educación Pública en 1988. En el examen de la cavidad bucal de los escolares se utilizaron los criterios diagnósticos señalados por la Organización Mundial de la Salud. Resultados. Un total de 4 475 escolares de 5 a 12 años de edad participaron en el estudio. La prevalencia de caries dental en la población alcanzó 90.5%. El índice de necesidades de tratamiento fue elevado (79.6%. El promedio de los índices de caries en los escolares de 12 años de edad fue CPOD= 4.42 (desviación estándar –DE– 3.2 y CPOS= 6.53 (DE 4.8. Conclusiones. Los resultados de la encuesta subrayan la pertinencia de un programa preventivo de amplia cobertura, como el de fluoruración de la sal. Además, muestran que se requiere elaborar estrategias para mejorar el acceso de la población escolar a los servicios odontológicos del sistema de salud en México.Objective. To estimate the prevalence and severity of dental caries and the dental treatment necessities of school children in Mexico City. The studied population was surveyed for dental caries in 1988 to obtain data necessary for the National Program of Salt Fluoridation in Mexico. Material and methods. The population was selected with a sample frame based on a list of Kindergardens and primary schools registered at the Ministry of Public Education in 1988. The oral cavity examination was based on diagnostic criteria marked by the

The Dental Trauma Internet Calculator

DEFF Research Database (Denmark)

Gerds, Thomas Alexander; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg

2012-01-01

Background/Aim Prediction tools are increasingly used to inform patients about the future dental health outcome. Advanced statistical methods are required to arrive at unbiased predictions based on follow-up studies. Material and Methods The Internet risk calculator at the Dental Trauma Guide...... provides prognoses for teeth with traumatic injuries based on the Copenhagen trauma database: http://www.dentaltraumaguide.org The database includes 2191 traumatized permanent teeth from 1282 patients that were treated at the dental trauma unit at the University Hospital in Copenhagen (Denmark...

Bridging the gap in 1 st year dental material curriculum: A 3 year randomized cross over trial

Directory of Open Access Journals (Sweden)

Sivaranjani Gali

2015-01-01

Conclusion: Effectiveness of COSGD in terms of scores through MCQs is comparable to traditional lecture. However, most of the students perceive COSGD help them understand the theory better; co-relate clinically; more motivating and interesting than a traditional lecture. Feasibility in institution needs more time and resources to conduct COSGD within the dental material curriculum.

[The effects of Ketac Molar Aplicap glass-ionomer material on growth of cariogenic bacteria contained in the dental plaque].

Science.gov (United States)

Płuciennik-Stronias, Małgorzata; Sakowska, Danuta; Paul-Stalmaszczyk, Małgorzata; Bołtacz-Rzepkowska, Elzbieta

2012-01-01

In the aging population, the prevalence of root caries has been observed, which is a characteristic feature of the elderly people. The most important element used in caries prevention is fluoride, which is derived from the air, diet or fluoride-containing preparations and materials, e.g. glass-ionomer restorations. The aim of the study was to evaluate the effect of Ketac Molar Aplicap glass-ionomer on the growth of Lactobacillus sp. bacteria, one of the species most frequently found in the carietic focus of the tooth root. The study was carried out in 15 patients with good oral hygiene, in whom 35 fillings from Ketac Molar Aplicap conventional glass-ionomer material were performed. After 6 months, three-day dental plaque from these fillings and from the tooth enamel of the control group was examined. No statistically significant differences (p = 0.554) in the amounts of Lactobacillus sp. between the study and control group were revealed. Lack of inhibiting effect of glass-ionomer material on the growth of the dental plaque with Lactobacillus sp. after the time of observation is implied.

Smartphones and dental trauma: the current availability of apps for managing traumatic dental injuries.

Science.gov (United States)

Djemal, Serpil; Singh, Parmjit

2016-02-01

There is a general consensus regarding the lack of awareness regarding the emergency management of traumatic dental injuries amongst laypersons and dental professionals. This article aims to provide an overview of the apps available for traumatic dental injuries using smartphones. These apps may serve as a gateway for raising awareness of traumatic dental injuries. Three smartphone devices were used to access their respective app stores (Nokia Lumia 635 with Windows Phone OS 8.1; iPhone 5 with iOS 8.1; Samsung Galaxy Ace II with Android OS v2.3.6 Gingerbread). Nine phrases were searched: broken tooth/teeth; chipped tooth/teeth; dental emergency; dental injury; dental trauma; fractured tooth/teeth; knocked-out tooth/teeth; tooth/teeth injury; and tooth/teeth trauma. Seven apps for the Android and one app for the Apple operating system were relevant. The only Apple iOS app retrieved (Dental Trauma) was also found for the Android OS (Dental Trauma First Aid) and had the endorsement of the International Association of Dental Traumatology. AcciDent was the only app dedicated to traumatic dental injuries targeted solely towards dental professionals. Five other apps (Chipped Tooth Solution, Dental Crown Repair, Fixing Cracked Tooth, Repairing the Front Tooth and Solution to Broken Tooth) appeared to come from the same source (KBES). No traumatic dental injury apps were found for the Windows Phone OS. There are apps available for both patients and dentists that range in quality and on the whole lack real-life photographs. Future apps should continue to provide good quality, evidence-based and validated material. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Fracture-resistant monolithic dental crowns.

Science.gov (United States)

Zhang, Yu; Mai, Zhisong; Barani, Amir; Bush, Mark; Lawn, Brian

2016-03-01

To quantify the splitting resistance of monolithic zirconia, lithium disilicate and nanoparticle-composite dental crowns. Fracture experiments were conducted on anatomically-correct monolithic crown structures cemented to standard dental composite dies, by axial loading of a hard sphere placed between the cusps. The structures were observed in situ during fracture testing, and critical loads to split the structures were measured. Extended finite element modeling (XFEM), with provision for step-by-step extension of embedded cracks, was employed to simulate full failure evolution. Experimental measurements and XFEM predictions were self-consistent within data scatter. In conjunction with a fracture mechanics equation for critical splitting load, the data were used to predict load-sustaining capacity for crowns on actual dentin substrates and for loading with a sphere of different size. Stages of crack propagation within the crown and support substrate were quantified. Zirconia crowns showed the highest fracture loads, lithium disilicate intermediate, and dental nanocomposite lowest. Dental nanocomposite crowns have comparable fracture resistance to natural enamel. The results confirm that monolithic crowns are able to sustain high bite forces. The analysis indicates what material and geometrical properties are important in optimizing crown performance and longevity. Copyright © 2015 Academy of Dental Materials. All rights reserved.

Perception of Laypeople and Dental Professionals of Smile Esthetics

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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

Dental students′ compliance with antibiotic prescribing guidelines for dental infections in children

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Yee Chen Wong

2016-01-01

Full Text Available Context: To investigate the antibiotic prescribing training received by dental students, clinical experience in treating child patients, awareness of antibiotic prescribing guidelines, preparedness in antibiotic prescribing, and compliance with antibiotic prescribing guidelines for the management of dental infections in children. Methods: This was a cross-sectional study involving final year dentals students from Malaysian and Asian dental schools. A self-administered questionnaire consisting of five clinical case scenarios was e-mailed to all final year students at selected dental schools. Students′ responses were compared for each clinical case scenario with the prescribing guidelines of the American Academy of Pediatric Dentistry and the American Dental Association. Compliance in each scenario was tested for association with their preparedness in antibiotic prescribing, previous training on antibiotic prescribing and awareness of antibiotic prescribing guidelines using Chi-square test. Data collected were analyzed using SPSS statistics version 20. Results: A total of 108 completed responses were received. About 74 (69% students were from Malaysian dental schools. The compliance rate with prescribing guidelines ranged from 15.7% to 43.5%. Those attending Malaysian dental schools (47.3% and those who had treated child patient more often (46.3% were more likely (P < 0.05 to be aware of the guidelines. Those who had received antibiotic prescribing training (21.3% were more likely to think they were well prepared in antibiotic prescribing (P < 0.05. Conclusions: Final year dental students had low awareness and compliance with antibiotic prescribing guidelines. Further research is needed to investigate how compliance with the guidelines may be enhanced.

Influence of dental plaque pH on caries status and salivary microflora in children following comprehensive dental care under general anesthesia

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Yng-Tzer J. Lin

2018-03-01

Full Text Available Background/purpose: There is no report in examining dental plaque pH after dental care under general anesthesia. This study investigated the effects of comprehensive dental rehabilitation under general anesthesia on the oral environment of children with severe early childhood caries (S-ECC and the influence of dental plaque pH on caries recurrence and salivary microflora. Materials and methods: Thirty-seven children (mean age, 51.08 ± 9.68 months with S-ECC who underwent comprehensive dental treatment under general anesthesia were selected. Caries index, plaque pH, and Streptococcus mutans (SM and Lactobacillus (LB counts were evaluated during the initial examination and 6-month and 12-month follow-ups. Results: The plaque pH was significantly greater at the 6-month follow-up examination than at the initial examination (P = 0.006 and at the 12-month follow-up (P = 0.002, but there was no significant difference in plaque pH between the initial examination and the 12-month follow-up (P = 0.942. SM and LB counts at the sixth and twelfth months were significantly lower than the initial counts (P  0.05. Conclusion: The comprehensive dental rehabilitation under general anesthesia for children with S-ECC caused a temporary significant increase in the plaque pH at the sixth month and a significant reduction in the salivary microflora during the 12-month follow-up. Plaque pH did not demonstrate any strong correlations with caries status and salivary microflora in children with S-ECC. Keywords: caries status, plaque pH, salivary microflora

Is treatment under general anaesthesia associated with dental neglect and dental disability among caries active preschool children?

Science.gov (United States)

Kvist, T; Zedrén-Sunemo, J; Graca, E; Dahllöf, G

2014-10-01

To study if treatment under general anaesthesia (GA) is associated with dental neglect or dental disability. This was a retrospective study. Dental records of all children in the age 0-6 years who underwent GA at a specialist paediatric dentistry clinic during 2006-2011 were studied with regard to decayed-missed-filled teeth, traumatic injuries, emergency visits, behaviour management problems and the history of attendance. The final sample consisted of 134 children. Matched controls were selected among recall patients who had not received treatment under GA. Fishers exact test or Pearson Chi-square test analysed response distribution and comparisons between groups, and for multivariate analyses, logistic regression was used. The results show that children treated under GA had significantly higher caries prevalence, apical periodontitis and infections due to pulpal necrosis. Dental neglect as well as dental disability was significantly more prevalent in the GA group compared to the control group. In a multivariate analysis with dental neglect as independent factor, dental disability was the only significant factor (p = 0.006). Children treated under general anaesthesia were significantly more often diagnosed with both dental neglect and dental disability. Dental disability was the only factor significantly related to dental neglect. There is a need for improved documentation in the dental records to better identify dental neglect and dental disability, and also a continued training of dentists regarding child protection.

CONCURRENT CONTACT SENSITIZATION TO METALS IN DENTAL EXPOSURES

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Maya Lyapina

2018-03-01

Full Text Available Purpose: Sensitization to metals is a significant problem for both dental patients treated with dental materials and for dental professionals in occupational exposures. The purpose of the present study was to evaluate the incidence of concurrent contact sensitization to relevant for dental practice metals among students of dental medicine, students from dental technician school, dental professionals and patients. Material and Methods: A total of 128 participants were included in the study. All of them were patch-tested with nickel, cobalt, copper, potassium dichromate, palladium, aluminium, gold and tin. The results were subject to statistical analysis (p < 0.05. Results: For the whole studied population, potassium dichromate exhibited concomitant reactivity most often; copper and tin also often manifested co-reactivity. For the groups, exposed in dental practice, potassium dichromate and tin were outlined as the most often co-reacting metal allergens, but statistical significance concerning the co-sensitization to copper and the other metals was established only for aluminium. An increased incidence and OR for concomitant sensitization to cobalt and nickel was established in the group of dental students; to copper and nickel - in the control group; to palladium and nickel - in the group of dental professionals, the group of students of dental medicine and in the control group; to potassium dichromate and cobalt - in the group of dental students; to copper and palladium - in the control group of dental patients; to potassium dichromate and copper - in the group of dental professionals; to copper and aluminum - in the groups of students from dental technician school and of dental professionals; to copper and gold - in the groups of dental professionals and in the group of dental patients; to potassium dichromate and aluminum - in the group of dental professionals; to potassium dichromate and gold - in the group of dental professionals, and to

Can Dental Pulp Calcification Predict the Risk of Ischemic Cardiovascular Disease?

OpenAIRE

Khojastepour, Leila; Bronoosh, Pegah; Khosropanah, Shahdad; Rahimi, Elham

2013-01-01

Objective: To report the association of pulp calcification with that of cardiovascular disease (CVD) using digital panoramic dental radiographs. Materials and Methods: Digital panoramic radiographs of patients referred from the angiography department were included if the patient was under 55 years old and had non-restored or minimally restored molars and canines. An oral and maxillofacial radiologist evaluated the images for pulpal calcifications in the selected teeth. The sensitivity, specif...

Dental amalgam and mercury vapor release.

Science.gov (United States)

Osborne, J W

1992-09-01

Dental diseases are among the most common ailments, and dentists in the United States spend over 50% of their time in dental practice rebuilding carious, malformed, and traumatically injured teeth. It is logical, therefore, that the majority of the dental school curriculum is devoted to the diagnosis, prevention, and treatment of teeth with anomalies. Dentists have several choices of materials they can use to accomplish the task of rebuilding teeth. Besides amalgam, they have ceramic materials, resin composites, base-metal and noble casting alloys, and glass-ionomer cements to use to restore the posterior dentition. Each of these restorative materials has advantages and disadvantages, and the clinical judgment as to when a particular material should be used is given a high priority in dental education. Amalgam is the most widely used of these restorative materials, with 92% of dentists listing it as the material of choice in the posterior of the mouth (Clinical Research Associates, 1990). Dentists have been placing amalgams for over 150 years in the US. They placed 150 million last year, which represents over 75 tons of amalgam alloy. The reasons that dentists use this restorative material so frequently are its durability, ease of manipulation, and low cost. Numerous clinical studies have been conducted on the serviceability of amalgam. Most of these have been on the old, low-copper alloys, and results indicate that they last from 8 to 15 years (Bailit et al., 1979; Osborne et al., 1980; Qvist et al., 1986). In the past 20 years, vast improvements have been made in amalgams with the development of the high-copper systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Material Selection for a Manual Winch Rope Drum

OpenAIRE

Moses F. Oduori; Enoch K. Musyoka; Thomas O. Mbuya

2016-01-01

The selection of materials is an essential task in mechanical design processes. This paper sets out to demonstrate the application of analytical decision making during mechanical design and, particularly, in selecting a suitable material for a given application. Equations for the mechanical design of a manual winch rope drum are used to derive quantitative material performance indicators, which are then used in a multiple attribute decision making (MADM) model to rank the candidate materials....

Education About Dental Hygienists' Roles in Public Dental Prevention Programs: Dental and Dental Hygiene Students' and Faculty Members' and Dental Hygienists' Perspectives.

Science.gov (United States)

Pervez, Anushey; Kinney, Janet S; Gwozdek, Anne; Farrell, Christine M; Inglehart, Marita R

2016-09-01

In 2005, Public Act No. 161 (PA 161) was passed in Michigan, allowing dental hygienists to practice in approved public dental prevention programs to provide services for underserved populations while utilizing a collaborative agreement with a supervising dentist. The aims of this study were to assess how well dental and dental hygiene students and faculty members and practicing dental hygienists have been educated about PA 161, what attitudes and knowledge about the act they have, and how interested they are in additional education about it. University of Michigan dental and dental hygiene students and faculty members, students in other Michigan dental hygiene programs, and dental hygienists in the state were surveyed. Respondents (response rate) were 160 dental students (50%), 63 dental hygiene students (82%), 30 dental faculty members (26%), and 12 dental hygiene faculty members (52%) at the University of Michigan; 143 dental hygiene students in other programs (20%); and 95 members of the Michigan Dental Hygienists' Association (10%). The results showed that the dental students were less educated about PA 161 than the dental hygiene students, and the dental faculty members were less informed than the dental hygiene faculty members and dental hygienists. Responding dental hygiene faculty members and dental hygienists had more positive attitudes about PA 161 than did the students and dental faculty members. Most of the dental hygiene faculty members and dental hygienists knew a person providing services in a PA 161 program. Most dental hygiene students, faculty members, and dental hygienists wanted more education about PA 161. Overall, the better educated about the program the respondents were, the more positive their attitudes, and the more interested they were in learning more.

The relationship between dental status, food selection, nutrient intake, nutritional status, and body mass index in older people

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Wagner Marcenes

2003-05-01

Full Text Available This paper reviewed the findings from a national survey in Great Britain which assessed whether dental status affected older people's food selection, nutrient intake, and nutritional status. The survey analyzed national random samples of free-living and institution subjects for dental examination, interview, and four-day food diary as well as blood and urine tests In the free-living sample, intakes of non-starch polysaccharides, protein, calcium, non-heme iron, niacin, and vitamin C were significantly lower in edentulous as compared to dentate subjects. People with 21 or more teeth consumed more of most nutrients, particularly non-starch polysaccharides. This relationship in intake was not apparent in the hematological analysis. Plasma ascorbate and retinol were the only analytes significantly associated with dental status. Having 21 or more teeth increased the likelihood of having an acceptable body mass index (BMI. Thus, maintaining a natural and functional dentition defined as having more than twenty teeth into old age plays an important role in having a healthy diet rich in fruits and vegetables, a satisfactory nutritional status, and an acceptable BMI.

Patient satisfaction after receiving dental treatment among patients ...

African Journals Online (AJOL)

Background: Patient satisfaction is one of the indicators of the quality of care. Therefore it is one of the tools for evaluating the quality of care. Aim: To determine patient satisfaction after receiving dental treatment among patients attending public dental clinics in Dar-Es-Salaam. Material and methods: Five public dental clinics ...

First-year dental students' motivation and attitudes for choosing the dental profession.

Science.gov (United States)

Avramova, Nadya; Yaneva, Krassimira; Bonev, Boyko

2014-01-01

To determine first-year dental students' current motivation and attitudes for choosing the dental profession at the Faculty of Dental Medicine, Medical University - Sofia, Bulgaria. An anonymous questionnaire, consisting of 12 questions about students' socio-demographic profile and their motivation for choosing dentistry, was administered to 119 first-year dental students at the Faculty of Dental Medicine of the Medical University of Sofia. The study was conducted at the beginning of the 2012-2013 academic year. The data was processed and analyzed with the following software: Microsoft Windows Server 2008 R2; Microsoft SQL Server 2008; Internet Information Server 7.5.; Microsoft SharePoint Server 2010. The majority of the students (73%) were self-motivated for choosing dentistry as a career; 61% of them did not have relatives in the medical profession; 43% chose dental medicine because it is a prestigious, humane and noble profession; 50% - for financial security; 59% - because of the independence that it provides. There were no significant differences in the motivation between males and females. Independence, financial security and 'prestige' were the predominant motivating factors in this group of first-year dental students. Determining the reasons for choosing dentistry has important implications for the selection and training of students as well as for their future job satisfaction. Copyright © 2014 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Dental stories for children with autism.

Science.gov (United States)

Marion, Ian W; Nelson, Travis M; Sheller, Barbara; McKinney, Christy M; Scott, JoAnna M

2016-07-01

To investigate caregivers' preference regarding dental stories to prepare children with autism for dental visits. Caregivers of children with autism were allowed use of dental stories available via different media (paper, tablet computer, computer) and image types (comics or drawings, photographs, video). Caregivers completed pre- and postintervention surveys. Fisher's exact tests were used to determine associations between predictive factors and preferences. Forty initial and 16 follow-up surveys were completed. Subjects were primarily male (85%). Mean child age was 6.7 years. Nine (64%) caregivers found the dental story useful for themselves and their child. Two (14%) caregivers found the aid only helpful for themselves. Preferred media type was associated with language understanding (p = .038) and home media preference (p = .002). Practitioners should consider using dental stories to help prepare families and children for dental visits. Individual preferences for dental stories vary; using prior history can aid in selection. © 2016 Special Care Dentistry Association and Wiley Periodicals, Inc.

ARTIFICIAL NEURAL NETWORKS BASED GEARS MATERIAL SELECTION HYBRID INTELLIGENT SYSTEM

Institute of Scientific and Technical Information of China (English)

X.C. Li; W.X. Zhu; G. Chen; D.S. Mei; J. Zhang; K.M. Chen

2003-01-01

An artificial neural networks(ANNs) based gear material selection hybrid intelligent system is established by analyzing the individual advantages and weakness of expert system (ES) and ANNs and the applications in material select of them. The system mainly consists of tow parts: ES and ANNs. By being trained with much data samples,the back propagation (BP) ANN gets the knowledge of gear materials selection, and is able to inference according to user input. The system realizes the complementing of ANNs and ES. Using this system, engineers without materials selection experience can conveniently deal with gear materials selection.

A Software Application to Detect Dental Color

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Dan SÎMPĂLEAN

2015-09-01

Full Text Available Choosing dental color for missing teeth or tooth reconstruction is an important step and it usually raises difficulties for dentists due to a significant amount of subjective factors that can influence the color selection. Dental reconstruction presumes the combination between dentistry and chromatics, thus implying important challenges. Purpose: The aim of this study was to develop and implement a software application for detecting dental color to come to the aid of dentists and largely to remove the inherent subjectiveness of the human vision. Basic Methods: The implemented application was named Color Detection and the application’s source code is written using the C++ language. During application development, for creating the GUI (graphical user interface the wxWidgets 2.8 library it was used. Results: The application displays the average color of the selected area of interest, the reference color from the key collection existent in the program and also the degree of similarity between the original (the selected area of interest and the nearest reference key. This degree of similarity is expressed as a percentage. Conclusions: The Color Detection Program, by eliminating the subjectivity inherent to human sight, can help the dentist to select an appropriate dental color with precision.

Evaluation of digital dental models obtained from dental cone-beam computed tomography scan of alginate impressions

Science.gov (United States)

Jiang, Tingting; Lee, Sang-Mi; Hou, Yanan; Chang, Xin

2016-01-01

Objective To investigate the dimensional accuracy of digital dental models obtained from the dental cone-beam computed tomography (CBCT) scan of alginate impressions according to the time elapse when the impressions are stored under ambient conditions. Methods Alginate impressions were obtained from 20 adults using 3 different alginate materials, 2 traditional alginate materials (Alginoplast and Cavex Impressional) and 1 extended-pour alginate material (Cavex ColorChange). The impressions were stored under ambient conditions, and scanned by CBCT immediately after the impressions were taken, and then at 1 hour intervals for 6 hours. After reconstructing three-dimensional digital dental models, the models were measured and the data were analyzed to determine dimensional changes according to the elapsed time. The changes within the measurement error were regarded as clinically acceptable in this study. Results All measurements showed a decreasing tendency with an increase in the elapsed time after the impressions. Although the extended-pour alginate exhibited a less decreasing tendency than the other 2 materials, there were no statistically significant differences between the materials. Changes above the measurement error occurred between the time points of 3 and 4 hours after the impressions. Conclusions The results of this study indicate that digital dental models can be obtained simply from a CBCT scan of alginate impressions without sending them to a remote laboratory. However, when the impressions are not stored under special conditions, they should be scanned immediately, or at least within 2 to 3 hours after the impressions are taken. PMID:27226958

Cytocompatibility, cytotoxicity and genotoxicity analysis of dental implants

Science.gov (United States)

Reigosa, M.; Labarta, V.; Molinari, G.; Bernales, D.

2007-11-01

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B&W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use.

Cytocompatibility, cytotoxicity and genotoxicity analysis of dental implants

International Nuclear Information System (INIS)

M, Reigosa; V, Labarta; G, Molinari; D, Bernales

2007-01-01

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B and W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use

Online directed journaling in dental hygiene clinical education.

Science.gov (United States)

Gwozdek, Anne E; Klausner, Christine P; Kerschbaum, Wendy E

2009-01-01

Reflecting upon and sharing of clinical experiences in dental hygiene education is a strategy used to support the application of didactic material to patient care. The promotion of interactive, clinically focused discussions creates opportunities for students to foster critical thinking and socialization skills in dental hygiene practice. Twenty-eight dental hygiene students in their first semester of patient care utilized online directed journaling via blogging software, as a reflection and sharing strategy. Journal entries found critical thinking and socialization themes including connection of didactic material to clinical experience, student-patient interaction, student-student collaboration, and a vision of the professional role of the dental hygienist. A 7 item evaluation instrument provided data that the online journaling strategy was perceived as effective and valuable by the students. Online directed journaling is a strategy that has the potential to enhance critical thinking and socialization skills in dental hygiene clinical education.

Nanomodified Peek Dental Implants: Bioactive Composites and Surface Modification—A Review

Directory of Open Access Journals (Sweden)

Shariq Najeeb

2015-01-01

Full Text Available Purpose. The aim of this review is to summarize and evaluate the relevant literature regarding the different ways how polyetheretherketone (PEEK can be modified to overcome its limited bioactivity, and thereby making it suitable as a dental implant material. Study Selection. An electronic literature search was conducted via the PubMed and Google Scholar databases using the keywords “PEEK dental implants,” “nano,” “osseointegration,” “surface treatment,” and “modification.” A total of 16 in vivo and in vitro studies were found suitable to be included in this review. Results. There are many viable methods to increase the bioactivity of PEEK. Most methods focus on increasing the surface roughness, increasing the hydrophilicity and coating osseoconductive materials. Conclusion. There are many ways in which PEEK can be modified at a nanometer level to overcome its limited bioactivity. Melt-blending with bioactive nanoparticles can be used to produce bioactive nanocomposites, while spin-coating, gas plasma etching, electron beam, and plasma-ion immersion implantation can be used to modify the surface of PEEK implants in order to make them more bioactive. However, more animal studies are needed before these implants can be deemed suitable to be used as dental implants.

Relationship between Risk Behavior for Eating Disorders and Dental Caries and Dental Erosion.

Science.gov (United States)

Brandt, Lorenna Mendes Temóteo; Fernandes, Liege Helena Freitas; Aragão, Amanda Silva; Aguiar, Yêska Paola Costa; Auad, Sheyla Márcia; de Castro, Ricardo Dias; Cavalcanti, Sérgio D'Ávila Lins Bezerra; Cavalcanti, Alessandro Leite

2017-01-01

The aim of this study was to evaluate whether there is an association between risk behavior for eating disorders (EDs) and dental erosion and caries. A controlled cross-sectional study was conducted in Brazil, involving 850 randomly selected female adolescents. After evaluating risk behavior for eating disorders through the Bulimic Investigatory Test of Edinburgh, 12 adolescents were identified with severe risk behavior for EDs and matched to 48 adolescents without such risk. Dental examinations, anthropometric measurements, and eating habits and oral hygiene were performed. Adolescents with high severity eating disorder condition were not more likely to show dental caries ( p = 0.329; OR = 2.2, 95% CI: 0.35-13.72) or dental erosion ( p = 0.590; OR = 2.33; 95% CI: 0.56-9.70). Adolescents with high body mass index (BMI) were five times more likely to have high severity eating disorder condition ( p = 0.031; OR = 5.1; 95% CI: 1.61-23.07). Therefore, high severity risk behavior for EDs was not significantly associated with dental caries and dental erosion. However, high BMI was a risk factor for developing eating disorders and should be an alert for individuals with this condition.

A survey of local anaesthesia education in European dental schools

NARCIS (Netherlands)

Brand, H.S.; Kuin, D.; Baart, J.A.

2008-01-01

Objective: A survey of European dental schools was conducted in 2006 to determine the curricular structure, techniques and materials used in local anaesthesia teaching to dental students. Materials and methods: A questionnaire was designed to collect information about local anaesthesia education.

Dental Trauma Guide

DEFF Research Database (Denmark)

Andreasen, Jens Ove; Lauridsen, Eva Fejerskov; Christensen, Søren Steno Ahrensburg

2012-01-01

Diagnose and treatment of traumatic dental injuries is very complex due to the multiple trauma entities represented by 6 lunation types and 9 fracture types affecting both the primary and the permanent dentition. When it is further considered that fracture and lunation injuries are often combined...... problems in selecting proper treatment for some of these trauma types. To remedy this situation, an internet based knowledge base consisting of 4000 dental trauma cases with long term follow up is now available to the public and professionals, on the internet using the address www...

Is liberal independent dental practice in danger? Assessing forms of dental practice in the European Regional Organization (ERO) zone of the FDI World Dental Federation.

Science.gov (United States)

Wolf, Thomas Gerhard; Seeberger, Gerhard Konrad; Callaway, Angelika; Briseño-Marroquín, Benjamín; Rusca, Philippe; Frank, Michael; Otterbach, Ernst-Jürgen

2018-02-26

A trend towards increasingly new forms of dental practice has been observed in the FDI World Dental Federation. Elementary foundations such as the free dentist and therapy choice, and independent, free, self-responsible professional practice may be undermined. The current study is aimed at analyzing the general training framework, organization, and professional types of dental practice in the European Regional Organization (ERO) zone and at critically discussing selected aspects of changes in the dental profession. A questionnaire was developed by the ERO Working-Group "Liberal Dental Practice." Information about dental schools, professional organizations, dental practice regulations, and ambulatory healthcare centers was analyzed. Self-employed dental practice is the most common type of practice (51.7%). Dentists are allowed to work independently immediately after graduation (72.7%). Approximately one-third are organized as compulsory members in chambers/corporations. The density of dentists has a mean of 1,570 inhabitants per dentist. In most countries, there are no special rules for founding dental ambulatory healthcare centers. In a total of 353 universities of the ERO countries surveyed, 16,619 dentists per year were trained, with a trend toward a higher percentage of female students (63%). Despite modern forms of dental practice, the charter of the individual liberal dental profession (CED et al, 2013) should be respected and taken into account on the basis of ethical principles. The commercialization of the dental profession can be neutralized only by establishing and following well-defined ethical principles; oral healthcare quality can thus be ensured without the influence of third parties.

Nationwide survey on barriers for dental research in India

Directory of Open Access Journals (Sweden)

Kundendu Arya Bishen

2015-01-01

Full Text Available Objective: Research in the dental field is progressing at mightier speed worldwide, but an unfortunately representation of India at this platform is negligible. The present study was undertaken to unearth the barriers for dental research among dental professionals in Indian scenario. Materials and Methods: A cross-sectional questionnaire study was conducted on 1514 participant′s (Master of Dental Surgery and Bachelor of Dental Surgery staff and postgraduates in 40 dental colleges of India selected by multistage random sampling. The response rate was 75.7%. The survey was undertaken from July 2013 to December 2013. The survey instrument was 24-item, investigator developed, self-structured, close-ended, and self-administered questionnaire grouped into four categories that are, institutional/departmental support related barriers, financial/training support related barriers, time-related barriers, and general barriers. Results: Among all respondents 47.23% informed that they are administrative and educational work rather than research work as (P < 0.001. Overall 57.53% of study participants reported lack of administrative and technical support for research work as (P < 0.001. Overall 64.9% reported meager college funding was the barrier (P < 0.001. Overall 61.5% respondents reported lack of time to do research work due to clinical and teaching responsibilities (P < 0.001 was the barrier for research. Largely 80.25% agreed that, the lack of documentation and record maintenance are an obvious barrier for research (P < 0.001. Conclusions: Present study unearths certain barriers for research in an Indian scenario, which includes administrative overburden, lack of funds, and lack of documentation of the dental data. Governing authorities of dentistry in India have to make major interventions to make research non-intensive environment to research-friendly environment.

Utilization of radiometric method in evaluation of wear on human dental enamel in vitro by dental porcelain glazed and polished

International Nuclear Information System (INIS)

Adachi, Lena Katekawa; Campos, Tomie Nakakuki de; Adachi, Eduardo Makoto

2005-01-01

The dental porcelain is a material commonly used in prosthesis. Disadvantages of dental porcelain use include possibility to cause tooth or dental materials wear. Before its use in the mouth, surfaces are treated with polishing and/or glazing. This research used the radiometric method to verify the influence of these surface treatments on the porcelains of commercial brands: Ceramco II, Noritake and Finesse. This method was originally developed for dentifrice abrasiveness evaluation. Five specimens of dental enamel and 10 specimens of each porcelain (5 glazed, 5 polished) were used. The dental enamel was flattened and irradiated with neutrons from the IEA-R1 (IPEN/CNEN) nuclear reactor. Then it was weared by each porcelain in sliding motion, with water. After 2,500 cycles for each porcelain specimen, the released enamel residue was measured. The enamel wear was evaluated by measuring beta activity of 32 P transferred to water from the irradiated tooth. Results varied from 2.57 to 5.81 μg of enamel /mm 2 weared surface. There was no statistical difference (α=0.05) between dental enamel wear caused by the same porcelains glazed or polished. The results suggest that adequate surface finishing depend on the type of dental porcelain. (author)

First-wall/blanket materials selection for STARFIRE tokamak reactor

International Nuclear Information System (INIS)

Smith, D.L.; Mattas, R.F.; Clemmer, R.G.; Davis, J.W.

1980-01-01

The development of the reference STARFIRE first-wall/blanket design involved numerous trade-offs in the materials selection process for the breeding material, coolant structure, neutron multiplier, and reflector. The major parameters and properties that impact materials selection and design criteria are reviewed

Using Persuasive Design Principles in Motivational Feeling towards Children Dental Anxiety (CDA)

Science.gov (United States)

Salam, Sobihatun Nur-Abdul; Yahaya, Wan Ahmad Jaafar-Wan; Ali, Azillah-Mohd

This paper is focusing the potential use of persuasive design principles in motivating children's dental anxiety. The main intention of the paper is to emphasize an attempt of how persuasive design principle can be designed into educational material using CD ROM based multimedia learning environment to overcome the CDA. Firstly, we describe a problem domain which discuss about the universal feeling of CDA and secondly the current practices in handling those negative feelings. Thirdly, the conceptual background of PMLE and how the principle has been applied in designing the information interfaces and presentation of a persuasive multimedia learning environment (PMLE) are described. Fourthly, an experimental design was used to validate the effects of prototype which assessed children dental anxiety level before and after the demonstration and utilization of a PMLE. Primary school children age between seven and nine years old are selected as respondents. Fifthly, the result of the study has revealed the feedback from children regarding baseline test and children dental anxiety test. It shows how by using persuasive design principles as an overall strategy in designing PMLE was able to motivate children feelings towards dental anxiety and could let the children behave in a good manner for dental visit in the future.

Dental Charting. Learning Activities, Unit Tests, Progress Chart, and Work Sheet.

Science.gov (United States)

Texas Univ., Austin. Center for Occupational Curriculum Development.

These materials are part of a series dealing with skills and information needed by students in dental assisting. The individualized student materials are suitable for classroom, laboratory, or cooperative training programs. These student materials, designed to be used with the Dental Charting Student Manual, consist of learning activities, unit…

Development of ultra-hydrophilic and non-cytotoxic dental vinyl polysiloxane impression materials using a non-thermal atmospheric-pressure plasma jet

Science.gov (United States)

Kwon, Jae-Sung; Kim, Yong Hee; Choi, Eun Ha; Kim, Kyoung-Nam

2013-05-01

Dental vinyl polysiloxane (VPS) impression materials are widely used for the replication of intraoral tissue where hydrophilicity is important as the oral tissues are surrounded by wet saliva. Recent attempts to improve the wettability of VPS using a ‘surfactant’, however, have resulted in a high level of cytotoxicity. Hence, in this study, application of a non-thermal atmospheric-pressure plasma jet (NTAPPJ) on VPS and its effects in terms of both hydrophilicity and cytotoxicity were investigated. The results showed that the application of the plasma jet resulted in significant improvement of hydrophilicity of VPS that had no surfactant, whereby the results were similar to commercially available products with the surfactant. The surface chemical analysis results indicated that this was due to the oxidation and decreased amount of hydrocarbon on the surface following NTAPPJ exposure. Meanwhile, an NTAPPJ-treated sample was shown to be non-cytotoxic. Therefore, the use of dental VPS impression materials without any surfactant, in conjunction with an NTAPPJ treatment, is a promising method for ultra-hydrophilic but yet non-cytotoxic materials.

Development of ultra-hydrophilic and non-cytotoxic dental vinyl polysiloxane impression materials using a non-thermal atmospheric-pressure plasma jet

International Nuclear Information System (INIS)

Kwon, Jae-Sung; Kim, Kyoung-Nam; Kim, Yong Hee; Choi, Eun Ha

2013-01-01

Dental vinyl polysiloxane (VPS) impression materials are widely used for the replication of intraoral tissue where hydrophilicity is important as the oral tissues are surrounded by wet saliva. Recent attempts to improve the wettability of VPS using a ‘surfactant’, however, have resulted in a high level of cytotoxicity. Hence, in this study, application of a non-thermal atmospheric-pressure plasma jet (NTAPPJ) on VPS and its effects in terms of both hydrophilicity and cytotoxicity were investigated. The results showed that the application of the plasma jet resulted in significant improvement of hydrophilicity of VPS that had no surfactant, whereby the results were similar to commercially available products with the surfactant. The surface chemical analysis results indicated that this was due to the oxidation and decreased amount of hydrocarbon on the surface following NTAPPJ exposure. Meanwhile, an NTAPPJ-treated sample was shown to be non-cytotoxic. Therefore, the use of dental VPS impression materials without any surfactant, in conjunction with an NTAPPJ treatment, is a promising method for ultra-hydrophilic but yet non-cytotoxic materials. (paper)

The Effect of Dental Insurance on the Use of Dental Care For Older Adults: A Partial Identification Analysis*

Science.gov (United States)

Kreider, Brent; Moeller, John; Manski, Richard J.; Pepper, John

2014-01-01

We evaluate the impact of dental insurance on the use of dental services using a potential outcomes identification framework designed to handle uncertainty created by unknown counterfactuals – that is, the endogenous selection problem – as well as uncertainty about the reliability of self-reported insurance status. Using data from the Health and Retirement Study, we estimate that utilization rates of adults older than 50 would increase from 75% to around 80% under universal dental coverage. PMID:24890257

Understanding dental CAD/CAM for restorations--dental milling machines from a mechanical engineering viewpoint. Part B: labside milling machines.

Science.gov (United States)

Lebon, Nicolas; Tapie, Laurent; Duret, Francois; Attal, Jean-Pierre

2016-01-01

Nowadays, dental numerical controlled (NC) milling machines are available for dental laboratories (labside solution) and dental production centers. This article provides a mechanical engineering approach to NC milling machines to help dental technicians understand the involvement of technology in digital dentistry practice. The technical and economic criteria are described for four labside and two production center dental NC milling machines available on the market. The technical criteria are focused on the capacities of the embedded technologies of milling machines to mill prosthetic materials and various restoration shapes. The economic criteria are focused on investment cost and interoperability with third-party software. The clinical relevance of the technology is discussed through the accuracy and integrity of the restoration. It can be asserted that dental production center milling machines offer a wider range of materials and types of restoration shapes than labside solutions, while labside solutions offer a wider range than chairside solutions. The accuracy and integrity of restorations may be improved as a function of the embedded technologies provided. However, the more complex the technical solutions available, the more skilled the user must be. Investment cost and interoperability with third-party software increase according to the quality of the embedded technologies implemented. Each private dental practice may decide which fabrication option to use depending on the scope of the practice.

Dental waste characterization in the city of Ilam in 2014

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Farzad Kazemi

2016-05-01

Full Text Available Background: Dental wastes are one of the environmental issues due to toxic and pathogenic agents such as pathological wastes, pharmaceutical and chemical etc have particular sensitivity. The aim of this study was to determine the dental waste management and related factors in the city of Ilam. Methods: In this cross-sectional study, the studied community was all the sixteen dental clinics in Ilam. Five samples of each clinic per week (Saturday, Sunday and Wednesday were selected. Thereafter waste sample was manually separated into 36 components and were weighed using a laboratory scale with an accuracy of 0.01 g. Each component was weighed five times and the mean value obtained for each component was considered. Production per capita was calculated for each person. Data were analyzed using descriptive statistics, SPSS and Excel software. Results: The per capita percent for infectious waste section was 51%. The average of infectious waste is 201.13 g. The per capita percent for chemical, pharmaceutical waste section was 36% with an average of 142.48 g. The per capita percent for toxicity section was 13% in the dental clinics with the weighted average of 48.78 g. According to the results of the checklist, further dental clinics have been poorly managed. Conclusion: According to the presence of various materials and different components with different characteristics in the dental wastes, the optimal management of this type of wastes should be carried out based on the specific characteristics, which include programs to reduce waste production, segregation, recycle and reuse.

Quantitative and Qualitative Investigation of Yazd Dental Center Waste

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Mehdi Mokhtari

2015-12-01

Full Text Available Compared to other medical clinics, dental centers produce a relatively small amount of healthcare waste. However, they are responsible for the production of certain amounts of waste that can cause serious health and environmental hazards if not treated properly. Determining the quantity and quality of dental waste is quite necessary to plan the machinery, personnel, and transportation methods. In the current analytical cross-sectional study, 22 dental clinics were randomly selected from among 145 dental centers in Yazd. For each clinic, three samples were manually collected and distributed at the end of the work day once a week (the day was randomly chosen. The components were classified into four groups based on their characteristics and potential risk. Afterward, the collected data were analyzed using Excel. The mean per capita daily waste generation in the Yazd dental clinics was 80.179 g for each patient. In general, the Yazd dental clinics generate approximately 4 tons of waste every year. Out of this amount, infectious waste, domestic waste, chemical-pharmaceutical waste, and sharp waste account for 49.30%, 33.33%, 13.7%, and 4.2%, respectively. The results of the current study and the small amount of waste generated in Yazd suggest that a special safe site should be constructed for infectious, sharp, and keen waste; private companies should collect such waste and transfer it to this site after the waste is disinfected; and the waste should then be transferred to a municipal waste hygienic disposal site. In regard to chemical waste that may contain hazardous materials, like mercury, no suggestions other than safe burial are made.

Dental Calculus Arrest of Dental Caries.

Science.gov (United States)

Keyes, Paul H; Rams, Thomas E

An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. These observations further document the potential protective effects of dental calculus mineralization against dental caries.

Quality criteria for phase change materials selection

International Nuclear Information System (INIS)

Vitorino, Nuno; Abrantes, João C.C.; Frade, Jorge R.

2016-01-01

Highlights: • Selection criteria of phase change materials for representative applications. • Selection criteria based on reliable solutions for latent heat transfer. • Guidelines for the role of geometry and heat transfer mechanisms. • Performance maps based on PCM properties, operating conditions, size and time scales. - Abstract: Selection guidelines are primary criterion for optimization of materials for specific applications in order to meet simultaneous and often conflicting requirements. This is mostly true for technologies and products required to meet the main societal needs, such as energy. In this case, gaps between supply and demand require strategies for energy conversion and storage, including thermal storage mostly based on phase change materials. Latent heat storage is also very versatile for thermal management and thermal control by allowing high storage density within narrow temperature ranges without strict dependence between stored thermal energy and temperature. Thus, this work addressed the main issues of latent heat storage from a materials selection perspective, based on expected requirements of applications in thermal energy storage or thermal regulation. Representative solutions for the kinetics of latent heat charge/discharge were used to derive optimization guidelines for high energy density, high power, response time (from fast response to thermal inertia), etc. The corresponding property relations were presented in graphical forms for a wide variety of prospective phase change materials, and for wide ranges of operating conditions, and accounting for changes in geometry and mechanisms.

An in vitro atomic force microscopic study of commercially available dental luting materials.

Science.gov (United States)

Djordje, Antonijevic; Denis, Brajkovic; Nenadovic, Milos; Petar, Milovanovic; Marija, Djuric; Zlatko, Rakocevic

2013-09-01

The aim of this in vitro study was to compare the surface roughness parameters of four different types of dental luting agents used for cementation of implant restorations. Five specimens (8 mm high and 1 mm thick) of each cement were made using metal ring steelless molds. Atomic Force Microscope was employed to analyze different surface texture parameters of the materials. Bearing ratio analysis was used to calculate the potential microgap size between the cement and implant material and to calculate the depth of the valleys on the cement surface, while power spectral density (PSD) measurements were performed to measure the percentage of the surface prone to bacterial adhesion. Glass ionomer cement showed significantly lower value of average surface roughness then the other groups of the materials (P cement experience the lowest percentage of the surface which promote bacterial colonization. Glas ionomer cements present the surface roughness parameters that are less favorable for bacterial adhesion than that of zinc phosphate, resin-modified glass ionomer and resin cements. Copyright © 2013 Wiley Periodicals, Inc.

The Dental School Interview As a Predictor of Dental Students' OSCE Performance.

Science.gov (United States)

Park, Sang E; Price, Mirissa D; Karimbux, Nadeem Y

2018-03-01

The aim of this study was to evaluate the use of the dental school admissions interview score as a noncognitive indicator of performance in predoctoral dental education, with specific attention to whether a correlation existed between the admissions interview scores and performance on the objective structured clinical examination (OSCE). The study population consisted of all 175 students in the Harvard School of Dental Medicine (HSDM) DMD Classes of 2012 through 2016. Data on students' gender and age on entering dental school were self-reported using their applications for admission to the HSDM DMD program. Data on students' OSCE scores for three examination sessions were collected from the Office of Dental Education. The results showed that the students' interview scores did not significantly correlate with OSCE performance on any of the three exams. Performance on the first and second OSCEs did, however, correlate with performance on the third OSCE (pinterview score. These results suggest that although the admissions interview scores can serve as an important resource in student selection, with the lack of association between interview and OSCE scores, it is possible that the communication skills required for the interview do not directly overlap with those required for OSCE success.

Machinable glass-ceramics forming as a restorative dental material.

Science.gov (United States)

Chaysuwan, Duangrudee; Sirinukunwattana, Krongkarn; Kanchanatawewat, Kanchana; Heness, Greg; Yamashita, Kimihiro

2011-01-01

MgO, SiO(2), Al(2)O(3), MgF(2), CaF(2), CaCO(3), SrCO(3), and P(2)O(5) were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhardness. Three-point bending strength and fracture toughness were applied by UTM according to ISO 6872: 1997(E). XRD showed that the glass crystallized at 892°C (second crystallization temperature+20°C) for 3 hrs consisted mainly of calcium-mica and fluorapatite crystalline phases. Average hardness (3.70 GPa) closely matched human enamel (3.20 GPa). The higher fracture toughness (2.04 MPa√m) combined with the hardness to give a lower brittleness index (1.81 µm(-1/2)) which indicates that they have exceptional machinability. Bending strength results (176.61 MPa) were analyzed by Weibull analysis to determine modulus value (m=17.80). Machinability of the calcium mica-fluorapatite glass-ceramic was demonstrated by fabricating with CAD/CAM.

Pneumoconiosis and respiratory problems in dental laboratory technicians: Analysis of 893 dental technicians

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Dilek Ergün

2014-10-01

Full Text Available Objectives: To explore the rate of pneumoconiosis in dental technicians (DTP and to evaluate the risk factors. Material and Methods: Data of 893 dental technicians, who were admitted to our hospital in the period January 2007–May 2012, from 170 dental laboratories were retrospectively examined. Demographic data, respiratory symptoms, smoking status, work duration, working fields, exposure to sandblasting, physical examination findings, chest radiographs, pulmonary function tests and high-resolution computed tomography results were evaluated. Results: Dental technicians’ pneumoconiosis rate was 10.1% among 893 cases. The disease was more common among males and in those exposed to sandblasting who had 77-fold higher risk of DTP. The highest profusion subcategory was 3/+ (according to the International Labour Organization (ILO 2011 standards and the large opacity rate was 13.3%. Conclusions: To the best of our knowledge, it was the largest DTP case series (N = 893/90 in the literature in English. Health screenings should be performed regularly for the early diagnosis of pneumoconiosis, which is an important occupational disease for dental technicians.

Awareness of Infection Control Protocols Among Dental Students in Babylon Dental Faculty

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Khalil Ibraheem Zaidan

2018-02-01

Full Text Available Infection control and knowledge of common "infectious diseases" is essential for safe dental practice. Conveyance of infectious diseases is likely "from one individual to another during dental procedures", thorough" blood-borne" viruses and bacteria   "such as hepatitis" , human immunodeficiency virus (HIV. Thence in dental practice, the  sterilization and particular protection  is of most importance Process in  dental procedures,  and patient sponsor settings seek specific strategies guide to prevent the  transmission of diseases among dental students , oral verdure care staffs and their patients. Aim: Current study highlight  the methods and behavior  to evaluate  the  benefits of awareness, stance and pursuit of infection control between dental students in training dental clinic at Babylon  dental collage . Materials and Methods: A cross-sectional wipe using a rear ordered questionnaire was executed. The reconnaissance consisted of 38 closed-ended questions that included the key areas of infection control, including hand hygiene, personal preservation, sterilization and disinfection and ecological infection monitoring. There were also questions to elicit perceptions regarding the treatment of HBV and HIV/AIDS patients. Results: Survey study was done for dental students replied to the reconnaissance. Their situation and realization across infection control in college teaching  clinic .The results were assorted between 100% were orderly using gloves and 96% mask   with patient to 6% were orderly wore eye glasses. The type of sterilization of instrument was 90% autoclave and 10% oven and from analysis of data revealed most teaching clinics devoid of instruction post about control of infection control measures   Conclusion: "Improved compliance with recommended infection control procedures is required for all dentists" and graduated dental students  predestined in the existing project. Enduring instruction "programs and short

Research on dental implant and its industrialization stage

Science.gov (United States)

Dongjoon, Yang; Sukyoung, Kim

2017-02-01

Bone cell attachment to Ti implant surfaces is the most concerned issue in the clinical implant dentistry. Many attempts to achieve the fast and strong integration between bone and implant have been tried in many ways, such as selection of materials (for example, Ti, ZrO2), shape design of implant (for example, soft tissue level, bone level, taped or conical, etc), and surface modification of implants (for example, roughed. coated, hybrid), etc. Among them, a major consideration is the surface design of dental implants. The surface with proper structural characteristics promotes or induces the desirable responses of cells and tissues. To obtain such surface which has desirable cell and tissue response, a variety of surface modification techniques has been developed and employed for many years. In this review, the method and trend of surface modification will be introduced and explained in terms of the surface topography and chemistry of dental implants.

Dental students' motivation and the context of learning

DEFF Research Database (Denmark)

Kristensen, Bettina Tjagvad; Netterstrom, Ingeborg; Kayser, Lars

2009-01-01

This qualitative study shows dental students' motives for choosing the dental education and how the motives influence their motivation at the first semester of study. Further the study demonstrates the relevance of the context of learning. This issue is of importance when planning a curriculum...... for the dental education. The material consists of interviews with eight dental students. The results show that dental students were focused on their future professional role, its practical dimensions and their future working conditions. Their motivation for choosing the dental education was found to influence...... their motivation for studying and their experience of the relevance of the first semester. The dental students who had co-education with the medical students at the first year of study missed a dental context and courses with clinically relevant contents. In conclusion, our data signify the importance...

32 CFR 199.13 - TRICARE Dental Program.

Science.gov (United States)

2010-07-01

... necessary for the residents to be professionally qualified to provide dental care for dependent children..., and licensed by an appropriate authority. (10) Dentist. Doctor of Dental Medicine (D.M.D.) or Doctor... active duty, Selected Reserve or Individual Ready Reserve member. (2) Child. To be eligible, the child...

Prevalence of dental anomalies and enamel hypoplasia in primary dentition among preschool children of West Godavari District, Andhra Pradesh -A cross - sectional study

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Suzan Sahana

2013-01-01

Full Text Available Background: It is axiomatic that Pediatric dental anomalies and enamel hypoplasia (E.H are routinely encountered in primary dentition and early detection and prudent management of the condition facilitates normal occlusal development. Objectives: To determine the prevalence of various dental anomalies and enamel hypoplasia in preschool children between two to six years of age. Materials & Method: A total of 1898 children, between two to six years were randomly selected and screened for dental anomalies and enamel hypoplasia The chi square test was used to analyze the data statistically. Results: The overall prevalence rate of dental anomalies and enamel hypoplasia in this study was 0.63% and 8.95% respectively. Double teeth were the most frequently reported dental anomaly while supernumerary teeth were least reported. None of them reported with hypodontia.

Utilization of dental care: An Indian outlook

Science.gov (United States)

Gambhir, Ramandeep Singh; Brar, Prabhleen; Singh, Gurminder; Sofat, Anjali; Kakar, Heena

2013-01-01

Oral health has a significant impact on the quality of life, appearance, and self-esteem of the people. Preventive dental visits help in the early detection and treatment of oral diseases. Dental care utilization can be defined as the percentage of the population who access dental services over a specified period of time. There are reports that dental patients only visit the dentist when in pain and never bother to return for follow-up in most cases. To improve oral health outcomes an adequate knowledge of the way the individuals use health services and the factors predictive of this behavior is essential. The interest in developing models explaining the utilization of dental services has increased; issues like dental anxiety, price, income, the distance a person had to travel to get care, and preference for preservation of teeth are treated as barriers in regular dental care. Published materials which pertain to the use of dental services by Indian population have been reviewed and analyzed in depth in the present study. Dental surgeons and dental health workers have to play an adequate role in facilitating public enlightenment that people may appreciate the need for regular dental care and make adequate and proper use of the available dental care facilities. PMID:24082719

Dental implant survival rate in well-controlled diabetic patients. A systematic review.

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Heber Arbildo

2015-12-01

Full Text Available Background: Dental implants have now become one of the most popular options for replacing a missing tooth. On the other hand, diabetes mellitus is a systemic disease that affects a large part of the population and is generally considered an absolute or relative contraindication to implant therapy. Aim: To determine the survival rate of dental implants in controlled diabetic patients through a systematic review. Material and methods: A systematic search in Pubmed, SciELO and RedALyC databases was performed. The selection criteria were: studies published in the last 10 years, with at least 20 controlled diabetic patients, reporting survival rate and number of implants placed, with follow-up periods equal to or longer than 1 year, including a control group of healthy patients. Methodological quality was analyzed with the follwing scales: Jadad and Downs & Black’s CMQ. Results: Three articles with a follow-up period between 1 and 12 years were analyzed. The overall survival rate of dental implants in diabetic controlled patients was 97.43%. Conclusion: The reviewed literature suggests that survival rate of dental implants in well-controlled diabetic patients is similar to non-diabetic patients.

Occupational Stress in Dental Practice amongst Government ...

African Journals Online (AJOL)

Objectives: The aim of this study is to compare the level of occupational stress amongst government-employed and private dental practitioners in eastern Nigeria. Materials and methods: A total of 62 questionnaires were randomly distributed among government-employed and private practicing dental surgeons with five ...

Selection, development and characterisation of plasma facing materials for ITER

International Nuclear Information System (INIS)

Barabash, V.; Akiba, M.; Ulrickson, M.; Vieider, G.

1996-01-01

The current status of the selection of the armour materials for first wall, limiters and divertor are presented. The candidate armour materials are beryllium, tungsten and carbon base materials (mainly carbon fiber composites). The selection of the references grades from these material classes is discussed and the candidate grades are described. The main reasons for the selection of the reference grades are also discussed. The urgent materials R and D needs for the development of the design are described briefly. (orig.)

Comparative Effectiveness of Dental Anatomy Carving Pedagogy: A Systematic Review.

Science.gov (United States)

de Azevedo, Renato de A; da Rosa, Wellington Luiz de O; da Silva, Adriana F; Correa, Marcos B; Torriani, Marcos A; Lund, Rafael G

2015-08-01

The aim of this study was to review the effectiveness of methods used for teaching dental anatomy carving to dental students in operative dentistry as evaluated in published studies. This systematic review is described in accordance with the PRISMA statement. Two independent reviewers performed a systematic literature search of research published from January 1945 until May 2014. Seven databases were screened: MedLine (PubMed), Lilacs, IBECS, Web of Science, Scopus, SciELO, and The Cochrane Library. After removing duplicates, only studies using dental carving to assess the practical knowledge of anatomy were selected. The tabulated data were organized by title of article, names of authors, number of students assessed, assessment method, material used, groups tested, main results, and conclusions. The methodology quality was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions. Initially, 2,258 studies were identified in all databases. Five articles met the eligibility criteria and were included in this review. According to these studies, the geometric method, teaching step-by-step along with the teacher, and adjuvant methods such as the use of tutors and teaching through digital media with DVDs proved to be effective in improving learning. There is no standard technique that is widely accepted for the teaching of dental carving, nor is there an appropriately validated method of evaluation to verify whether the teaching methods used are effective for the acquisition of skills and expertise in dental anatomy by students.

Readability Levels of Dental Patient Education Brochures.

Science.gov (United States)

Boles, Catherine D; Liu, Ying; November-Rider, Debra

2016-02-01

The objective of this study was to evaluate dental patient education brochures produced since 2000 to determine if there is any change in the Flesch-Kincaid grade level readability. A convenience sample of 36 brochures was obtained for analysis of the readability of the patient education material on multiple dental topics. Readability was measured using the Flesch-Kincaid Grade Level through Microsoft Word. Pearson's correlation was used to describe the relationship among the factors of interest. Backward model selection of multiple linear regression model was used to investigate the relationship between Flesch-Kincaid Grade level and a set of predictors included in this study. A convenience sample (n=36) of dental education brochures produced from 2000 to 2014 showed a mean Flesch-Kincaid reading grade level of 9.15. Weak to moderate correlations existed between word count and grade level (r=0.40) and characters count and grade level (r=0.46); strong correlations were found between grade level and average words per sentence (r=0.70), average characters per word (r=0.85) and Flesch Reading Ease (r=-0.98). Only 1 brochure out of the sample met the recommended sixth grade reading level (Flesch-Kincaid Grade Level 5.7). Overall, the Flesch-Kincaid Grade Level of all brochures was significantly higher than the recommended sixth grade reading level (preadability of the brochures. However, the majority of the brochures analyzed are still testing above the recommended sixth grade reading level. Copyright © 2016 The American Dental Hygienists’ Association.

Advances in dental imaging.

Science.gov (United States)

Brown, J E

2001-04-01

The number of dental radiographs taken in the UK has steadily increased over the past 20 years--recently estimating around 18 million taken in the general dental services alone, and dental radiographs now account for nearly 25% of all medical radiographic exposures. Radiographs remain our most useful diagnostic aid. Their strength is in demonstrating hard tissue pathology, which makes radiographs particularly effective in the maxillofacial region. Although well accepted in this capacity, there remain a number of limitations and drawbacks to conventional radiographs which recent developments have begun to overcome. There have been improvements in the scope and capabilities of dental imaging equipment. There has also been a continuing effort to reduce radiation-induced harm by limiting our exposure to it. This has been possible both through the introduction of new methods and protocols for reducing individual radiation exposures and by the creation of guidelines for selecting radiographs more effectively and thereby reducing the total number of radiographs taken.

A Review on Dental Amalgam Corrosion and Its Consequences

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M Fathi

2004-02-01

Full Text Available Dental amalgam is still the most useful restorative material for posterior teeth and has been successfully used for over a century. Dental amalgam has been widely used as a direct filling material due to its favorable mechanical properties as well as low cost and easy placement. However, the mercury it contains raises concerns about its biological toxicity and environmental hazard. Although in use for more than 150 years, dental amalgam has always been suspected more or less vigorously due to its alleged health hazard. Amalgam restorations often tarnish and corrode in oral environment. Corrosion of dental amalgam can cause galvanic action. Ion release as a result of corrosion is most important. Humans are exposed to mercury and other main dental metals via vapor or corrosion products in swallowed saliva and also direct absorption into blood from oral mucosa. During recent decades the use of dental amalgam has been discussed with respect to potential toxic effects of mercury components. In this article, the mechanisms of dental amalgam corrosion are described and results of researches are reviewed. It finally covers the corrosion of amalgams since this is the means by which metals, including mercury, can be released within oral cavity. Keywords: Dental amalgam, Amalgam corrosion, Biocompatibility, Mercury release, Amalgam restoration

Synthesis and characterization of dental composites

Science.gov (United States)

Djustiana, Nina; Greviana, Nadia; Faza, Yanwar; Sunarso

2018-02-01

During the last few decades, the increasing demands in esthetic dentistry have led to the development of dental composites material that provide similar appearance to the natural teeth. Recently, esthetic trend was an issue which increase the demand for teeth restorations that is similar with the origin. The esthetics of dental composite are more superior compared to amalgam, since its color look similar with natural teeth. Various dental composites have been developed using many type of fillers such as amorphous silica, quartz), borosilicate, Li-Sr-Ba-Al glass and oxide: zirconia and alumina. Researchers in Faculty of Dentistry University of Padjadjaran have prepared dental composites using zirconia-alumina-silica (ZAS) system as the filler. The aim is to improve the mechanical properties and the esthetic of the dental composites. The ZAS was obtained from chemical grade purity chemicals and Indonesia's natural sand as precursors its characterization were also presented. This novel method covers the procedure to synthesis and characterize dental composites in Padjadjaran University and some review about dental composites in global research.

The vicious cycle of dental fear: exploring the interplay between oral health, service utilization and dental fear

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Spencer A John

2007-01-01

Full Text Available Abstract Background Based on the hypothesis that a vicious cycle of dental fear exists, whereby the consequences of fear tend to maintain that fear, the relationship between dental fear, self-reported oral health status and the use of dental services was explored. Methods The study used a telephone interview survey with interviews predominantly conducted in 2002. A random sample of 6,112 Australian residents aged 16 years and over was selected from 13 strata across all States and Territories. Data were weighted across strata and by age and sex to obtain unbiased population estimates. Results People with higher dental fear visited the dentist less often and indicated a longer expected time before visiting a dentist in the future. Higher dental fear was associated with greater perceived need for dental treatment, increased social impact of oral ill-health and worse self-rated oral health. Visiting patterns associated with higher dental fear were more likely to be symptom driven with dental visits more likely to be for a problem or for the relief of pain. All the relationships assumed by a vicious cycle of dental fear were significant. In all, 29.2% of people who were very afraid of going to the dentist had delayed dental visiting, poor oral health and symptom-driven treatment seeking compared to 11.6% of people with no dental fear. Conclusion Results are consistent with a hypothesised vicious cycle of dental fear whereby people with high dental fear are more likely to delay treatment, leading to more extensive dental problems and symptomatic visiting patterns which feed back into the maintenance or exacerbation of existing dental fear.

Development of a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value

International Nuclear Information System (INIS)

Kueppers, C.; Sering, M.; Poppe, B.; Poplawski, A.; Looe, H.K.; Beyer, D.; Pfaffenberger, A.; Chofor, N.; Eenboom, F.

2012-01-01

The research project on the development a concept for radiation patients exposure assessment during dental X-ray examinations and statistical data acquisition for the determination of a diagnostic reference value includes the following issues: Fundamental facts: dental X-ray examination techniques, dose relevant factors and characteristics during X-ray examinations, radiation exposed organs during dental X-ray examinations, dose assessment based on phantoms. Materials and methodologies of the project: TLD measurements using the phantom, calculation of the effective dose during dental X-ray examinations, properties and settings of the reference facilities for the determination of radiation exposure, selection of dental offices, dosimetric measurements, data acquisition and statistical evaluation. Results of dosimetric examinations: results of dosimetric measurements at reference facilities, results of dosimetric measurements in dental offices. Discussion of the concept for the determination of the radiation exposure during dental X-ray examinations.

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

Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

Energy Technology Data Exchange (ETDEWEB)

Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T [Research Unit of Advanced Ceramic, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok (Thailand); Padipatvuthikul, P, E-mail: raayaa_chula@hotmail.com [Faculty of Dentistry, Srinakharinwirot University, Bangkok (Thailand)

2011-10-29

Silicon nitride (Si{sub 3}N{sub 4}) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si{sub 3}N{sub 4} ceramic as a dental core material. The white Si{sub 3}N{sub 4} was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si{sub 3}N{sub 4} ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si{sub 3}N{sub 4} specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder (<150 micrometer, Pyrex) with 5 wt% of zirconia powder (3 wt% Y{sub 2}O{sub 3} - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si{sub 3}N{sub 4} specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10{sup -6} deg. C{sup -1}, rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

Analytical methods for the measurement of polymerization kinetics and stresses of dental resin-based composites: A review

Directory of Open Access Journals (Sweden)

Mehrsima Ghavami-Lahiji

2017-01-01

Full Text Available Resin-based composites are commonly used restorative materials in dentistry. Such tooth-colored restorations can adhere to the dental tissues. One drawback is that the polymerization shrinkage and induced stresses during the curing procedure is an inherent property of resin composite materials that might impair their performance. This review focuses on the significant developments of laboratory tools in the measurement of polymerization shrinkage and stresses of dental resin-based materials during polymerization. An electronic search of publications from January 1977 to July 2016 was made using ScienceDirect, PubMed, Medline, and Google Scholar databases. The search included only English-language articles. Only studies that performed laboratory methods to evaluate the amount of the polymerization shrinkage and/or stresses of dental resin-based materials during polymerization were selected. The results indicated that various techniques have been introduced with different mechanical/physical bases. Besides, there are factors that may contribute the differences between the various methods in measuring the amount of shrinkages and stresses of resin composites. The search for an ideal and standard apparatus for measuring shrinkage stress and volumetric polymerization shrinkage of resin-based materials in dentistry is still required. Researchers and clinicians must be aware of differences between analytical methods to make proper interpretation and indications of each technique relevant to a clinical situation.

Selective nanoscale growth of lattice mismatched materials

Science.gov (United States)

Lee, Seung-Chang; Brueck, Steven R. J.

2017-06-20

Exemplary embodiments provide materials and methods of forming high-quality semiconductor devices using lattice-mismatched materials. In one embodiment, a composite film including one or more substantially-single-particle-thick nanoparticle layers can be deposited over a substrate as a nanoscale selective growth mask for epitaxially growing lattice-mismatched materials over the substrate.

Selection and challenges for LFR reactor materials

Energy Technology Data Exchange (ETDEWEB)

Weisenburger, A.; Jianu, A.; Del Giacco, M.; Fetzer, R.; Heinzel, A.; Mueller, G. [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Pulsed Power and Microwave Technology

2013-07-01

Nuclear energy using Fast GenIV reactors can fulfil future demands concerning CO2 free, base load capability and sustainability. One of the most promising coolants especially due to its high thermal inertia is liquid lead (Pb). Since several years researches all over the world investigate this coolant and its impact on the reactor design and by that on the materials to be selected. The LEADER project, a follow up of ELSY, aims to design a prototypical demonstrator ALFRED and to continue with several design related aspects of the ELFR reactor. For a demonstrator the criteria of material selection are somewhat different to a commercial type like the ELFR. Material selection for ELFR of course considers all the aspects relevant for ALFRED plus the targeted burn up and the expected total dpa related damage especially of the fuel pins. In the past compatibility of structural material (steels like 316L, T91 and 15-15Ti (1.4970)) that can be employed for Pb cooled fast nuclear reactors were investigated in several EU projects like EUROTRANS and worldwide. Solubility of steel alloying elements like Ni, Fe, Cr is the driving force for the reduced corrosion resistance in contact with Pb. In-situ oxidation is the acknowledged measure to protect steels in Pb up to certain temperatures that are material dependent. Based on experiments and the derived temperature limits the average core outlet temperatures of ALFRED and the ELFR are set to 480 C. The most challenging conditions with respect to temperature are at the fuel assembly and the heat exchangers. For both, thin stable oxide scales with negligible reduction in heat transfer are the requested protection method. This presentation will give an overview on the selected materials for ALFRED and ELFR considering, beside pure compatibility, the influence of mechanical interaction like creep and fretting. (orig.)

Bioinspired design of dental multilayers.

Science.gov (United States)

Huang, M; Wang, R; Thompson, V; Rekow, D; Soboyejo, W O

2007-01-01

This paper considers the use of bioinspired functionally graded structures in the design of dental multi-layers that are more resistant to sub-surface crack nucleation. Unlike existing dental crown restorations that give rise to high stress concentration, the functionally graded layers (between crown materials and the joins that attach them to dentin) are shown to promote significant reductions in stress and improvements in the critical crack size. Special inspiration is drawn from the low stress concentrations associated with the graded distributions in the dentin-enamel-junction (DEJ). The implications of such functionally graded structures are also discussed for the design of dental restorations.

Oral rehabilitation with dental implants in oligodontia patients

NARCIS (Netherlands)

Finnema, KJ; Raghoebar, GM; Meijer, HJA; Vissink, A

2005-01-01

Purpose: The aim of this retrospective report was to evaluate the treatment outcome of oral rehabilitation with dental implants in oligodontia patients. Materials and Methods: Thirteen oligodontia patients treated with dental implants were examined clinically and radiographically (follow-up 3 +/- 2

Prevalence of dental caries among school-going children in Namakkal district: A cross-sectional study

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Ramachandran Karunakaran

2014-01-01

Full Text Available Aim: The aim of this study is to determine the prevalence of dental caries in primary teeth among 4-6 years old school going children in the Namakkal District. Materials and Methods: The study covered a total of 850 school going children in a total of 26 schools in the Namakkal district of Tamil Nadu. The age group selected for this study ranged from 4 to 6 years of age. Each child was examined in their respective schools by one of the four calibrated examiners and decay, missing and filled teeth (dmft index was recorded along with demographic details. This study was done in September-October 2013 in a span of 1 month duration. Results: Of 850 children examined, 560 (65.88% children had dental caries. Mean dmft score was 2.86. Prevalence of dental caries was higher in boys (69.6% than in girls (61.5%. The untreated decay teeth accounted for 92.4%. Conclusion: The prevalence of dental caries among 4-6 years old children is high in the Namakkal district. The need for the creation of dental awareness among children and their primary caregivers is crucial and the need for developing immediate oral health promotion strategies including an increase in school dental health programs is recommended.

The Dental Solid Waste Management in Different Categories of Dental Laboratories in Abha City, Saudi Arabia

Science.gov (United States)

Haralur, Satheesh B.; Al-Qahtani, Ali S.; Al-Qarni, Marie M.; Al-Homrany, Rami M.; Aboalkhair, Ayyob E.; Madalakote, Sujatha S.

2015-01-01

Aim: To study the awareness, attitude, practice and facilities among the different categories of dental laboratories in Abha city. Materials and Methods: A total of 80 dental technicians were surveyed in the study. The dental laboratories included in the study were teaching institute (Group I), Government Hospital (Group II), Private Dental Clinic (Group III) and Independent laboratory (Group IV). The pre-tested anonymous questionnaire was used to understand knowledge, attitude, facilities, practice and orientation regarding biomedical waste management. Results: The knowledge of biomedical waste categories, colour coding and segregation was better among Group I (55-65%) and Group II (65-75%). The lowest standard of waste disposal was practiced at Group IV (15-20%) and Group III (25-35%). The availability of disposal facilities was poor at Group IV. The continuous education on biomedical waste management lacked in all the Groups. Conclusion: The significant improvement in disposal facilities was required at Group III and Group IV laboratories. All dental technicians were in need of regular training of biomedical waste management. Clinical Significance: The dental laboratories are an integral part of dental practice. The dental laboratories are actively involved in the generation, handling and disposal of biomedical waste. Hence, it is important to assess the biomedical waste management knowledge, attitude, facilities and practice among different categories of dental laboratories. PMID:26962373

An assessment of dental anxiety in nonclinical setting among Saudi Arabian children using Abeer Children Dental Anxiety Scale

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Shabina Shafi

2015-01-01

Full Text Available Introduction: Dental anxiety is an abnormal fear or dread of visiting the dentist for preventive care or therapy and unwarranted anxiety over dental procedures. It is a common problem that affects people of all ages and appears to develop mostly in childhood and adolescence. The present study assesses dental anxiety among children in a nonclinical setting among Saudi Arabian children who underwent preventive treatment procedure using Abeer Children Dental Anxiety Scale (ACDAS. Materials and Methods: The children attending an oral health program were screened for oral health problems and preventive treatment such as topical fluoride applications. The dental anxiety among children was assessed using ACDAS. Results: A total of 51 children participated in the research. The results showed that maximum children were not scared of dentist in nonclinical setting and had low dental anxiety levels. Overall, 74% of the child subjects had ACDAS scores below 26. Conclusions: Knowing the degree of anxiety of dental children is important to guide them through their dental experience and carry on the preventive dental treatments at an early age in nonclinical setting. Their level of cooperation will improve, and anxiety will be reduced as well. Further research is required to compare dental anxiety levels in children between clinical and nonclinical setting.

Treatment planning for patients with dental arch asymmetry caused by loss of a premolar on one side of the mouth

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Ivanova О.P.

2013-09-01

Full Text Available The objective of this study is to determine a selection criterion that is applicable for the treatment of patients with dental arch asymmetry caused by loss of a premolar on one side of the mouth. Material and methods. Fifty-seven patients (first maturity level who had some teeth extracted for orthodontic treatment were included in the study. The patients were divided into basic and control groups. We proposed to shape the extraction socket immediately after the extraction of a permanent tooth. In the basic group the extraction sockets were filled with osteoplastic material. Patients in the control group refused any surgical interventions. Results. According to a given criterion, the correlation between tooth size and dental arch parameters has been determined. When applying this criterion for finding the correlation, the frontal distal diagonal size of the dental arch was multiplied by 1.14 coefficient. The sum of the mesiodistal diameters of seven teeth in the half-arc was subtracted from the obtained value. The value which was equal to 0±1.0mm indicated the correlation between tooth size and dental arch parameters. Conclusion. If there is a correlation between tooth size and dental arch parameters, it is advisable to provide treatment associated with having the post-extraction socket opened and implant therapy performed (most commonly with the use of intraosseous dental implants.

Research on giving antibacteria activity of tailored dental materials; Gin ion ni yoru shikayo zairyo no kokinsei fuyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The secondary dental caries easily occur by breeding of bacteria in cavities between living body and composite resin, false tooth or root of tailored tooth as tooth repairing materials. The antibacteria activity of tailored dental materials was thus studied by implanting Ag ion. The antibacteria effect with time after culture of caries bacteria was studied by implanting Ag ion into SiO2 powder, PMMA samples and Ti alloy samples at 20 and 200keV in energy of ion. In addition, the antibacteria activity of SiO2 powder as composite material was found at 25keV which was previously effective for the antibacteria activity. This SiO2 filler (Ag{sup +} filler) showed the antibacteria activity on every bacteria sample after 2h, and in particular, could kill all of 3 kinds of bacteria obtained from a composite resin surface after 12h. The number of living S. salivarius was reduced by half after 12h. The application of the composite resin filler implanted with Ag{sup +} is significant to prevent recurrence of caries. 5 refs., 27 figs., 7 tabs.

Motivating and Inhibiting Factors to Oral-Dental Health Behavior in Adolescents: a Cross-Sectional Study

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Zahra Hosseini

2016-11-01

Full Text Available Background Oral-dental diseases, especially tooth decay, are among the most common diseases in the world which usually begin in adolescence. Oral health during this period of life has a huge impact on the reduction of dental problems. This study aimed to determine motivating and inhibiting factors to oral-dental health behavior in adolescents. Materials and Methods This cross-sectional which had a descriptive and analytical design was conducted on 10-12th grade students in Kashan city, Iran. Using multi-stage sampling method and based on sampling size formula, a total of 290 of the students were randomly selected from the schools and were enrolled into the study. Then they received a research-made questionnaire containing questions about the knowledge and motivating and inhibiting factors to oral-dental health behavior. The collected data were analyzed using SPSS V.20 by independent t-test, ANOVA, and Pearson correlation coefficient. Results Of all, 62.8% of students brushed their teeth at least once a day. Moreover, 11.7% used dental floss once a day and 6.6% visited a dentist every six months. Oral-dental health behavior had a significant relationship with gender (P0.05. Conclusion When designing educational plans and interventions for improving oral-dental health behavior in students, it is necessary to adopt measures to enhance motivating factors and eliminate inhibiting factors.

Hyperactive Children are at Risk of Dental Caries -An Analytical Study

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C Jeevika

2013-01-01

Full Text Available Background: Attention-deficit/hyperactivity disorder (ADHD is well recognized in western countries, but there were no much reports of ADHD from India. Aim: To determine the relationship of ADHD with dental caries. Materials & Method : A cross-sectional analytical study was carried out among 120 children aged around 8-15 years who were randomly selected from normal and special schools located in Chennai city. The children were categorized as ADHD according to the criteria of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV.The questionnaire was given to parents and teachers. It included details of DSM- IV criteria, age, sex, demographic details, past dental history, hours diet chart and any medication taken previously. The oral hygiene status was assessed using Oral Hygiene index simplified (OHI-S and the caries experience was recorded using DMFT index. Categorical data were compared by the Chi-square test. The odds ratio (OR was calculated with logistic regression. A multivariate analysis was carried out to adjust for gender, dental caries status of primary and permanent teeth. Results : Males are more in ADHD group when compared to females. Oral Hygiene Status of ADHD group was significantly better than control group. ADHD children were 3.1 times more odds of getting dental caries than children in the control group.

ABOUT INDEX EVALUATION OF MATERIAL RESOURCE SUPPLIER SELECTION

OpenAIRE

V. A. Skochinskaya

2008-01-01

The paper analyzes existing methods for evaluation of material resource supplier selection. It shows advantages and shortcomings of the present evaluation systems. The necessity for application of an index evaluation is justified in the paper. The paper contains rating (index) evaluation for material resource supplier selection which is based on the application of quantitative (index) tool instead of an expert (numerical) evaluation. 

Occupational contact dermatitis amongst dentists and dental technicians

OpenAIRE

Lugović-Mihić, Liborija; Ferček, Iva; Duvančić, Tomislav; Bulat, Vedrana; Ježovita, Josip; Novak-Bilić, Gaby; Šitum, Mirna

2016-01-01

Since the working medical personnel including dentists and dental technicians mainly use their hands, it is understandable that the most common occupational disease amongst medical personnel is contact dermatitis (CD) (80%-90% of cases). Development of occupational CD is caused by contact of the skin with various substances in occupational environment. Occupational etiologic factors for dental personnel are foremost reactions to gloves containing latex, followed by various dental materials...

LGBT Coverage in U.S. Dental Schools and Dental Hygiene Programs: Results of a National Survey.

Science.gov (United States)

Hillenburg, Kenneth L; Murdoch-Kinch, Carol A; Kinney, Janet S; Temple, Henry; Inglehart, Marita R

2016-12-01

The aims of this study were to assess curricular coverage of lesbian, gay, bisexual, and transgender (LGBT) content in U.S. and Canadian dental schools and U.S. dental hygiene programs, including hours of LGBT content, pedagogy used, and assessment methods, and to determine whether respondents perceived their institution's coverage as adequate. Data were collected from academic deans at 32 U.S. and two Canadian dental schools and from program directors at 71 U.S. dental hygiene programs (response rates 49%, 20%, 23%, respectively). The results showed that 29% of responding dental schools and 48% of responding dental hygiene programs did not cover LGBT content. Among the respondents, dental schools dedicated on average 3.68 hours and dental hygiene programs 1.25 hours in required settings to LGBT content. Lectures (dental schools 68%, dental hygiene programs 45%) and small group instruction (43%, 25%) were reported as the most common methodology used in teaching this content. Most of the responding dental schools and dental hygiene programs covered HIV (85%, 53%), oral disease risk (63%, 54%), and barriers to accessing health care for LGBT people (58%, 38%). Up to a third reported no need for coverage of topics such as sexual orientation (21%, 32%), coming out (29%, 37%), transitioning (29%, 38%), and sex reassignment surgery (32%, 35%). Assessment was through written examinations (41%, 30%) and faculty-observed patient interactions (21%, 23%); some respondents (20%, 33%) reported no assessment of learning outcomes. The most frequently endorsed strategies for increasing LGBT content were receiving curricular material focusing on LGBT-related health issues and health disparities and having trained faculty to teach LGBT content.

Potential hazards and artifacts of ferromagnetic and nonferromagnetic surgical and dental materials and devices in nuclear magnetic resonance imaging

International Nuclear Information System (INIS)

New, P.F.J.; Rosen, B.R.; Brady, T.J.

1983-01-01

The risks to patients with metal surgical implants who are undergoing nuclear magnetic resonance (NMR) imaging and the artifacts caused by such implants were studied. Twenty-one aneurysm and other hemostatic clips and a variety of other materials (e.g., dental amalgam, 14 karat gold) were used. Longitudinal forces and torques were found to be exerted upon 16 of the 21 clips. With five aneurysm clips, forces and torques sufficient to produce risk of hemorrhage from dislocation of the clip from the vessel or aneurysm, or cerebral injury by clip displacement without dislodgement were identified. The induced ferromagnetism was shown to be related to the composition of the alloys from which the clips were manufactured. Clips with 10-14% nickel are evidently without sufficient induced ferromagnetism to cause hazard. The extent of NMR imaging artifacts was greater for materials with measurable ferromagnetic properties, but metals without measurable ferromagnetism in our tests also resulted in significant artifacts. Dental amalgam and 14 karat gold produced no imaging artifacts, but stainless steels in dentures and orthodontic braces produced extensive artifacts in the facial region

[Preliminary study of bonding strength between diatomite-based dental ceramic and veneering porcelains].

Science.gov (United States)

Lu, Xiao-li; Gao, Mei-qin; Cheng, Yu-ye; Zhang, Fei-min

2015-04-01

In order to choose the best veneering porcelain for diatomite-based dental ceramic substrate, the bonding strength between diatomite-based dental ceramics and veneering porcelains was measured, and the microstructure and elements distribution of interface were analyzed. The coefficient of thermal expansion (CTE) of diatomite-based dental ceramics was detected by dilatometry. Three veneering porcelain materials were selected with the best CTE matching including alumina veneering porcelain (group A), titanium porcelain veneering porcelain (group B), and E-max veneering porcelain (group C). Shear bonding strength was detected. SEM and EDS were used to observe the interface microstructure and element distribution. Statistical analysis was performed using SPSS 17.0 software package. The CTE of diatomite-based dental ceramics at 25-500 degrees centigrade was 8.85×10-6K-1. The diatomite-based substrate ceramics combined best with group C. Shear bonding strength between group A and C and group B and C both showed significant differences(P<0.05). SEM and EDS showed that the interface of group C sintered tightly and elements permeated on both sides of the interface. The diatomite-based substrate ceramics combines better with E-max porcelain veneer.

Current dental adhesives systems. A narrative review.

Science.gov (United States)

Milia, Egle; Cumbo, Enzo; Cardoso, Rielson Jose A; Gallina, Giuseppe

2012-01-01

Adhesive dentistry is based on the development of materials which establish an effective bond with the tooth tissues. In this context, adhesive systems have attracted considerable research interest in recent years. Successful adhesive bonding depends on the chemistry of the adhesive, on appropriate clinical handling of the material as well as on the knowledge of the morphological changes caused on dental tissue by different bonding procedures. This paper outlines the status of contemporary adhesive systems, with particular emphasis on chemical characteristics and mode of interaction of the adhesives with enamel and dentinal tissues. Dental adhesives are used for several clinical applications and they can be classified based on the clinical regimen in "etch-and-rinse adhesives" and "self-etch adhesives". Other important considerations concern the different anatomical characteristics of enamel and dentine which are involved in the bonding procedures that have also implications for the technique used as well as for the quality of the bond. Etch-and-rinse adhesive systems generally perform better on enamel than self-etching systems which may be more suitable for bonding to dentine. In order to avoid a possible loss of the restoration, secondary caries or pulp damage due to bacteria penetration or due to cytotoxicity effects of eluted adhesive components, careful consideration of several factors is essential in selecting the suitable bonding procedure and adhesive system for the individual patient situation.

Influence of different restorative materials on the stress distribution in dental implants.

Science.gov (United States)

Datte, Carlos-Eduardo; Tribst, João-Paulo-Mendes; Dal Piva, Amanda-Maria-de Oliveira; Nishioka, Renato-Sussumu; Bottino, Marco-Antonio; Evangelhista, Alexandre-Duarte M; Monteiro, Fabrício M de M; Borges, Alexandre-Luiz-Souto

2018-05-01

To assist clinicians in deciding the most suitable restorative materials to be used in the crowns and abutment in implant rehabilitation. For finite element analysis (FEA), a regular morse taper implant was created using a computer aided design software. The implant was inserted at the bone model with 3 mm of exposed threads. An anatomic prosthesis representing a first maxillary molar was modeled and cemented on the solid abutment. Considering the crown material (zirconia, chromium-cobalt, lithium disilicate and hybrid ceramic) and abutment (Titanium and zirconia), the geometries were multiplied, totaling eight groups. In order to perform the static analysis, the contacts were considered bonded and each material was assigned as isotropic. An axial load (200 N) was applied on the crown and fixation occurred on the base of the bone. Results using Von-Mises criteria and micro strain values were obtained. A sample identical to the CAD model was made for the Strain Gauge (SG) analysis; four SGs were bonded around the implant to obtain micro strain results in bone tissue. FEA results were 3.83% lower than SG. According to the crown material, it is possible to note that the increase of elastic modulus reduces the stress concentration in all system without difference for bone. Crown materials with high elastic modulus are able to decrease the stress values in the abutments while concentrates the stress in its structure. Zirconia abutments tend to concentrate more stress throughout the prosthetic system and may be more susceptible to mechanical problems than titanium. Key words: Finite element analysis, dental implants, ceramic.

ABOUT INDEX EVALUATION OF MATERIAL RESOURCE SUPPLIER SELECTION

Directory of Open Access Journals (Sweden)

V. A. Skochinskaya

2008-01-01

Full Text Available The paper analyzes existing methods for evaluation of material resource supplier selection. It shows advantages and shortcomings of the present evaluation systems. The necessity for application of an index evaluation is justified in the paper. The paper contains rating (index evaluation for material resource supplier selection which is based on the application of quantitative (index tool instead of an expert (numerical evaluation. 

Dental enamel defects in children with coeliac disease

NARCIS (Netherlands)

Werink, Claar D.; van Diermen, Denise E.; Aartman, Irene H. A.; Heymans, Hugo S. A.

2007-01-01

OBJECTIVE: The aim of this study was to investigate whether Dutch children with proven coeliac disease show specific dental enamel defects, and to asses whether children with the same gastrointestinal complaints, but proved no-coeliac disease, lack these specific dental enamel defects. MATERIALS AND

Biological effects of radiation from dental radiography. Council on Dental Materials, Instruments, and Equipment

International Nuclear Information System (INIS)

Gibbs, S.J.

1982-01-01

Clearly, there is ample evidence of adverse effects of radiation in sufficient doses. There is at present no proof of such effects from doses commonly employed in dental practice; however, it has not been possible to prove the absence of such effects. Most experts now agree that there may be a small, difficult to quantify risk of cancer or genetic mutation from diagnostic exposure in patients and in personnel exposed during work. Prudence dictates acceptance of this position until proof to the contrary is available. This report has presented recent attempts to quantify the risk to patients based on speculative calculations and extrapolations. Indices of population risks indicate that medical radiology is the largest source of human-made genetic and leukemogenic radiation burden to the American public. Dental radiology contributes a small-but not necessarily insignificant-portion. Of major concern is the increasing use of radiation for diagnostic purposes in both medicine and dentistry. Technological advances have reduced exposure per examination; presumably this trend will continue so that total exposure of populations to radiation in the healing arts will not increase. Recent analyses suggest that the cancer risk to a patient from a dental radiographic examination is of the order of one in a million; the genetic risk is substantially less, about one in a billion. The risks appear to be essentially equal for full-mouth intraoral and for panoramic examinations. These estimates are numerically quite small, but the effects are severe. Thus, these risks cannot be ignored. However, we currently accept risks of similar magnitude in our daily lives [Table 9]50,51 In addition, the risk of failure to make an accurate diagnosis may be greater than the risk from exposure to the radiation from a justified and properly conducted radiographic examination

Dental Calculus Arrest of Dental Caries

OpenAIRE

Keyes, Paul H.; Rams, Thomas E.

2016-01-01

Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human t...

Selection of materials in nuclear fuel: present and future

International Nuclear Information System (INIS)

Munoz-Reja, C.; Fuentes, L.; Garcia de la Infanta, J. M.; Munoz Sicilia, A.

2013-01-01

One of the main aspects of the nuclear fuel is the selection of materials for the components. The operating conditions of the fuel elements impose a major challenge to materials: high temperature, corrosive aqueous environment, high mechanical properties, long periods of time under these extreme conditions and what is the differentiating factor; the effect of irradiation. The materials are selected to fulfill these severe requirements and also to be able to control and to predict its behavior in the working conditions. Their development, in terms of composition and processing, is based on the continuous follow-up of the operation behavior. Many of these materials are specific of the nuclear industry, such as the uranium dioxide and the zirconium alloys. This article presents the selection and development of the nuclear fuel materials as a function of the services requirements. It also includes a view of the new nuclear fuels materials that are being raised after Fukushima accident. (Author)

Perception and understanding of dental practitioners in provision of dental treatment to pregnant women in Karachi, Pakistan

Directory of Open Access Journals (Sweden)

Aisha Wali

2016-01-01

Full Text Available Aim: The aim of the study was to that assess the perceptions and understanding of dental practitioners in the provision of dental treatment to pregnant women. Materials and Methods: The study was a quantitative, cross-sectional type. A sample size of 200 dental practitioners were included in the study between the period of 6 months, i.e. June–December. A cluster sampling technique was employed covering four different dental institutes. A structured questionnaire was designed to assess the perception and understanding of dental practitioners in providing treatment to the pregnant women. Statistical Analysis: Statistical analysis was performed using SPSS version 19. Chi-square test was done to analyze the association of perception of dental practitioners in treating pregnant women in relation to gender. Results: A total of 200 dental practitioners filled the questionnaire out of which 43% (86 were males and 57% (114 were females. Eighty-two percent of the total participants said that it is safe to provide dental treatment during pregnancy, almost 90.4% of the total dentist interviewed was aware of the special position in which to place a pregnant woman on a dental chair. 85.5% of the study population do not prefer taking radiographs of a pregnant woman, 63% of the entire dentist surveyed prefers to use local anesthesia before any dental procedure on a pregnant patient. 96.5% care to educate their pregnant patient about improving dental health care. 59.5% of the dental practitioners said that they would consult the patient's gynecologist as a mandatory requirement before treating the patient. 57% of the dental practitioners answered with gingivitis. 70.5% agreed on scaling. The majority of the dentists prescribed paracetamol 85.5%. Conclusion: Little is known about the perception and utilization of dental practitioners in providing dental treatment to pregnant women in Pakistan. The present survey concluded that dental practitioners lack

Obesity and dental caries: systematic review.

Science.gov (United States)

Silva, Alexandre Emidio Ribeiro; Menezes, Ana Maria Baptista; Demarco, Flávio Fernando; Vargas-Ferreira, Fabiana; Peres, Marco Aurélio

2013-08-01

Identifying, through a systematic literature review, evidence of a possible association between obesity and dental caries. A search of articles published between 2005 and January 2012 was performed in the Medline/PubMed, LILACS and Web of Science databases. The quality of scientific evidence of the selected articles was assessed by the items proposed for observational studies in the Downs & Black instrument. Initially, 537 references were found; after checking the titles and abstracts by two independent researchers, twenty-eight articles were selected for complete reading. Ten of them that assessed the primary and/or permanent dentition observed a positive association between obesity and dental caries and one study found an inverse association. According to the Downs & Black classification, thirteen articles with good scientific evidence were found. The present review did not find sufficient evidence regarding the association between obesity and dental caries, and it did not clarify the possible role of diet and other possible effect modifiers on this association.

Obesity and dental caries: systematic review

Directory of Open Access Journals (Sweden)

Alexandre Emidio Ribeiro Silva

2013-08-01

Full Text Available OBJECTIVE Identifying, through a systematic literature review, evidence of a possible association between obesity and dental caries. METHODS A search of articles published between 2005 and January 2012 was performed in the Medline/PubMed, LILACS and Web of Science databases. The quality of scientific evidence of the selected articles was assessed by the items proposed for observational studies in the Downs & Black instrument. RESULTS Initially, 537 references were found; after checking the titles and abstracts by two independent researchers, twenty-eight articles were selected for complete reading. Ten of them that assessed the primary and/or permanent dentition observed a positive association between obesity and dental caries and one study found an inverse association. According to the Downs & Black classification, thirteen articles with good scientific evidence were found. CONCLUSIONS The present review did not find sufficient evidence regarding the association between obesity and dental caries, and it did not clarify the possible role of diet and other possible effect modifiers on this association.

The effects of acid erosion and remineralization on enamel and three different dental materials: FT-Raman spectroscopy and scanning electron microscopy analysis.

Science.gov (United States)

Soares, Luís Eduardo Silva; Soares, Ana Lúcia Silva; De Oliveira, Rodrigo; Nahórny, Sidnei

2016-07-01

FT-Raman spectroscopy and scanning electron microscopy (SEM) were employed to test the hypothesis that the beverage consumption or mouthwash utilization would change the chemistry of dental materials and enamel inorganic content. Bovine enamel samples (n = 36) each received two cavity preparations (n = 72), each pair filled with one of three dental materials (R: nanofilled composite resin, GIC: glass-ionomer cement, RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: artificial saliva, E: erosion/Pepsi Twist or EM: erosion + mouthwash/Colgate Plax). Reduction of carbonate content of enamel was greater in RE than RS (P erosion. Material degradation was greater after E and EM than S. GIC and RMGIC materials had a positive effect against acid erosion in the adjacent enamel after remineralization with mouthwash. The beverage and mouthwash utilization would change R and GIC chemical properties. A professional should periodically monitor the glass-ionomer and resin restorations, as they degrade over time under erosive challenges and mouthwash utilization. Microsc. Res. Tech., 2016. © 2016 Wiley Periodicals, Inc. Microsc. Res. Tech. 79:646-656, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Dental Implants and General Dental Practitioners of Nepal: A study of existing knowledge and need for further education

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Bhageshwar Dhami

2017-03-01

Full Text Available Background & Objectives: The use of dental implants in partially or completely edentulous patients has proved effective and an accepted treatment modality with predictable long-term success. Dental implants are becoming a popular choice for replacing the missing teeth because of increased awareness about implants both in dentists and patients. The objective of the study was to assess the basic knowledge and education about dental implants among general dental practitioners (GDPs of Nepal.Materials & Methods:  A cross sectional questionnaire was carried out among 110 GDPs which consist of twenty questions that were divided into three categories; first with some basic knowledge in implant dentistry, second with clinical knowledge of dental implants and third with dental implant education and training.Results: Out of 110 GDPs, 72.7% had basic knowledge about implant dentistry and 65.5% were not aware about advance surgical procedures like sinus lift and guided bone regeneration. All the GDPs were positive regarding more training and education in dental implants and 95.5% of them would like to incorporate dental implant treatment in their practice in future. Conclusion: GDPs should have adequate knowledge and training of dental implants which can be incorporated at undergraduate or post doctoral level so that they are skilled to provide quality dental implant therapy to their patients confidently.

Selective Integration in the Material-Point Method

DEFF Research Database (Denmark)

Andersen, Lars; Andersen, Søren; Damkilde, Lars

2009-01-01

The paper deals with stress integration in the material-point method. In order to avoid parasitic shear in bending, a formulation is proposed, based on selective integration in the background grid that is used to solve the governing equations. The suggested integration scheme is compared...... to a traditional material-point-method computation in which the stresses are evaluated at the material points. The deformation of a cantilever beam is analysed, assuming elastic or elastoplastic material behaviour....

Analysis of select facial and dental esthetic parameters.

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Nold, Sarah L; Horvath, Sebastian D; Stampf, Susanne; Blatz, Markus B

2014-01-01

This clinical study examined objective smile parameters in the natural anterior dentition. Standardized intraoral and extraoral photographs were taken of 106 Caucasian adults (54 women, 52 men) with a healthy dentition. The following parameters were analyzed: correlation of dental and facial midline, upper lip position and curvature, relationship of the maxillary anterior incisal curve with lower lip, number of teeth displayed in a smile, distance between maxillary anterior teeth and lower lip, slope of tooth, and lip arc. The simple frequency distribution of measured variables revealed an average smile with coinciding dental and facial midlines, an average smile line, and a straight upper lip curvature. With an average smile, the maxillary anterior teeth did not touch the lower lip, teeth were displayed up to the second premolar, and the maxillary anterior incisal curve was parallel to the lower lip. Oval was the most prevalent tooth form. A slope of 9 degrees was detected for the mean tooth arc and 13 degrees for the mean lip arc. The outcomes of this clinical study provide a quantifiable frame for esthetic evaluation, treatment planning, and restoration fabrication.

The effect of disinfecting solutions on the dimensional stability of dental alginate impression materials.

Science.gov (United States)

Muzaffar, Danish; Braden, Michael; Parker, Sandra; Patel, Mangala P

2012-07-01

Dimensional changes occur in set dental alginate impression materials when immersed in disinfecting solutions. In this contribution the dimensional changes of two alginates in two disinfecting solutions, and for two specimen thicknesses, have been studied. The results were analyzed theoretically. The dimensional changes of two commercial alginates (Blueprint Cremix and Hydrogum), have been measured, in distilled water and two disinfecting solutions (Perform ID/sodium hypochlorite), using a traveling microscope, at 5 min intervals over a period of 1h. Samples of simple geometry have been studied, namely rectangular strips with thicknesses of 1.5 and 3mm, respectively. In all cases, both alginates continuously shrank with time, in the three immersion liquids, over the hour of measurement, indicating transfer of water from the alginate into the external water or disinfecting solution. The t(1/2) shrinkage plots were generally linear, but with an intercept on the t(1/2) axis, indicating the possibility of an initial expansion at very short times. In most cases, the ratios of slopes for both thicknesses were 1.33-1.54, in contrast to the theoretical value of 2. Perform ID however gave anomalous results for the 1.5mm thick samples. At 10 min their shrinkage was 1.34-1.72%, compared with -0.42% to 0.67% in the other two media. The effects of thickness observed were not in accord with simple Fickian theory because of the various ions diffusing into and out of the alginate. Moreover, the water content of the alginate decreased consequent on the cross-linking process. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Sol-gel processes and materials. January 1970-August 1988 (Citations from the US Patent data base). Report for January 1970-August 1988

International Nuclear Information System (INIS)

1988-08-01

This bibliography contains citations of selected patents concerning Sol-Gel processes and Sol-Gel derived materials and products. Selected patents include Sol-Gel compositions, ceramic and refractory materials, fabrication of silica glass, cataylsts and catalyst supports, nuclear fuels preparation, abrasives for grinding wheels, Sol-Gel production of microspheres, Sol-Gel thin films and coatings, photographic materials, and dental materials. (Contains 71 citations fully indexed and including a title list.)

Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations.

Science.gov (United States)

Hedayat, Assem; Nagy, Nicole; Packota, Garnet; Monteith, Judy; Allen, Darcy; Wysokinski, Tomasz; Zhu, Ning

2016-05-01

Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The bur's cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

[Discomfort associated with dental extraction surgery and development of a questionnaire (QCirDental). Part I: Impacts and internal consistency].

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Bortoluzzi, Marcelo Carlos; Martins, Luciana Dorochenko; Takahashi, André; Ribeiro, Bianca; Martins, Ligiane; Pinto, Marcia Helena Baldani

2018-01-01

The scope of this study was to develop and validate a questionnaire (QCirDental) to measure the impacts associated with dental extraction surgery. The QCirDental questionnaire was developed in two steps; (1) question and item generation and selection, and (2) pretest of the questionnaire with evaluation of the its measurement properties (internal consistency and responsiveness). The sample was composed of 123 patients. None of the patients had any difficulty in understanding the QCirDental. The instrument was found to have excellent internal consistency with Cronbach's alpha reliability coefficient of 0.83. The principal component analysis (Kaiser-Meyer-Olkin Measure of Sampling Adequacy 0,72 and Bartlett's Test of Sphericity with p < 0.001) showed six (6) dimensions explaining 67.5% of the variance. The QCirDental presented excellent internal consistency, being a questionnaire that is easy to read and understand with adequate semantic and content validity. More than 80% of the patients who underwent dental extraction reported some degree of discomfort within the perioperative period which highlights the necessity to assess the quality of care and impacts of dental extraction surgery.

Evaluation of physiological and behavioral measures in relation to dental anxiety during sequential dental visits in children

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Rayen R

2006-01-01

Full Text Available Anxiety is a special variety of fear, experienced in anticipation of threatening stimuli. While some research workers have said that the response of a child improves with the number of visits, many have felt otherwise. The present study is yet another effort to find the patterns of anxiety in children during sequential dental visits. The main aim was to determine the physiological and behavioral variations during sequential dental visits and its impact on age and sex. The study was conducted at the outpatient Department of Pedodontics and preventive dentistry, Meenakshi Ammal Dental College and Hospital, Chennai to evaluate the physiological and behavioural measures of stress and anxiety in children. One hundred and fifteen children, between four and eleven years of age who reported for dental treatment were selected for the study.

Development of a novel resin-based dental material with dual biocidal modes and sustained release of Ag+ ions based on photocurable core-shell AgBr/cationic polymer nanocomposites.

Science.gov (United States)

Cao, Weiwei; Zhang, Yu; Wang, Xi; Chen, Yinyan; Li, Qiang; Xing, Xiaodong; Xiao, Yuhong; Peng, Xuefeng; Ye, Zhiwen

2017-07-01

Research on the incorporation of cutting-edge nano-antibacterial agent for designing dental materials with potent and long-lasting antibacterial property is demanding and provoking work. In this study, a novel resin-based dental material containing photocurable core-shell AgBr/cationic polymer nanocomposite (AgBr/BHPVP) was designed and developed. The shell of polymerizable cationic polymer not only provided non-releasing antibacterial capability for dental resins, but also had the potential to polymerize with other methacrylate monomers and prevented nanoparticles from aggregating in the resin matrix. As a result, incorporation of AgBr/BHPVP nanocomposites did not adversely affect the flexural strength and modulus but greatly increased the Vicker's hardness of resin disks. By continuing to release Ag + ions without the impact of anaerobic environment, resins containing AgBr/BHPVP nanoparticles are particularly suitable to combat anaerobic cariogenic bacteria. By reason of the combined bactericidal effect of the contact-killing cationic polymers and the releasing-killing Ag + ions, AgBr/BHPVP-containing resin disks had potent bactericidal activity against S. mutans. The long-lasting antibacterial activity was also achieved through the sustained release of Ag + ions due to the core-shell structure of the nanocomposites. The results of macrophage cytotoxicity showed that the cell viability of dental resins loading less than 1.0 wt% AgBr/BHPVP was close to that of neat resins. The AgBr/BHPVP-containing dental resin with dual bactericidal capability and long term antimicrobial effect is a promising material aimed at preventing second caries and prolonging the longevity of resin composite restorations.

Guidelines for the Development of Instructional Materials Selection Policies. Handbook I.

Science.gov (United States)

Motomatsu, Nancy, Ed.

This manual was developed to assist school district personnel in the development of policies and procedures for selecting instructional materials. The manual describes State of Washington laws and regulations that govern the selection, use, and disposal of instructional materials and presents criteria and guidelines for selecting materials. Also…

Prevalence of dental caries among 12–14 year old children in Qatar