Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement.

Science.gov (United States)

Huenges, Katharina; Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed.

Investigation of pathogenic genes in peri-implantitis from implant clustering failure patients: a whole-exome sequencing pilot study.

Directory of Open Access Journals (Sweden)

Soohyung Lee

Full Text Available Peri-implantitis is a frequently occurring gum disease linked to multi-factorial traits with various environmental and genetic causalities and no known concrete pathogenesis. The varying severity of peri-implantitis among patients with relatively similar environments suggests a genetic aspect which needs to be investigated to understand and regulate the pathogenesis of the disease. Six unrelated individuals with multiple clusterization implant failure due to severe peri-implantitis were chosen for this study. These six individuals had relatively healthy lifestyles, with minimal environmental causalities affecting peri-implantitis. Research was undertaken to investigate pathogenic genes in peri-implantitis albeit with a small number of subjects and incomplete elimination of environmental causalities. Whole-exome sequencing was performed on collected saliva samples via self DNA collection kit. Common variants with minor allele frequencies (MAF > = 0.05 from all control datasets were eliminated and variants having high and moderate impact and loss of function were used for comparison. Gene set enrichment analysis was performed to reveal functional groups associated with the genetic variants. 2,022 genes were left after filtering against dbSNP, the 1000 Genomes East Asian population, and healthy Korean randomized subsample data (GSK project. 175 (p-value <0.05 out of 927 gene sets were obtained via GSEA (DAVID. The top 10 was chosen (p-value <0.05 from cluster enrichment showing significance of cytoskeleton, cell adhesion, and metal ion binding. Network analysis was applied to find relationships between functional clusters. Among the functional groups, ion metal binding was located in the center of all clusters, indicating dysfunction of regulation in metal ion concentration might affect cell morphology or cell adhesion, resulting in implant failure. This result may demonstrate the feasibility of and provide pilot data for a larger research

3D finite element analysis of immediate loading of single wide versus double implants for replacing mandibular molar

Directory of Open Access Journals (Sweden)

Shrikar R Desai

2013-01-01

Full Text Available Purpose: The purpose of this finite element study was to compare the stresses, strains, and displacements of double versus single implant in immediate loading for replacing mandibular molar. Materials and Methods: Two 3D FEM (finite element method models were made to simulate implant designs. The first model used 5-mm-wide diameter implant to support a single molar crown. The second model used 3.75-3.75 double implant design. Anisotropic properties were assigned to bone model. Each model was analyzed with single force magnitude (100 N in vertical axis. Results: This FEM study suggested that micromotion can be controlled better for double implants compared to single wide-diameter implants. The Von Mises stress for double implant showed 74.44% stress reduction compared to that of 5-mm implant. The Von Mises elastic strain was reduced by 61% for double implant compared to 5-mm implant. Conclusion: Within the limitations of the study, when the mesiodistal space for artificial tooth is more than 12.5 mm, under immediate loading, the double implant support should be considered.

Clinical and Echocardiographic Outcomes Following Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement: Meta-Analysis and Meta-Regression.

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Mohananey, Divyanshu; Jobanputra, Yash; Kumar, Arnav; Krishnaswamy, Amar; Mick, Stephanie; White, Jonathon M; Kapadia, Samir R

2017-07-01

Transcatheter aortic valve replacement has become the procedure of choice for inoperable, high-risk, and many intermediate-risk patients with aortic stenosis. Conduction abnormalities are a common finding after transcatheter aortic valve replacement and often result in permanent pacemaker (PPM) implantation. Data pertaining to the clinical impact of PPM implantation are controversial. We used meta-analysis techniques to summarize the effect of PPM implantation on clinical and echocardiographic outcomes after transcatheter aortic valve replacement. Data were summarized as Mantel-Haenszel relative risk (RR) and 95% confidence intervals (CIs) for dichotomous variables and as standardized mean difference and 95% CI for continuous variables We used the Higgins I 2 statistic to evaluate heterogeneity. We found that patients with and without PPM have similar all-cause mortality (RR, 0.85; 95% CI, 0.70-1.03), cardiovascular mortality (RR, 0.84; 95% CI, 0.59-1.18), myocardial infarction (RR, 0.47; 95% CI, 0.20-1.11), and stroke (RR, 1.26; 95% CI, 0.70-2.26) at 30 days. The groups were also comparable in all-cause mortality (RR, 1.03; 95% CI, 0.92-1.16), cardiovascular mortality (RR, 0.69; 95% CI, 0.39-1.24), myocardial infarction (RR, 0.58; 95% CI, 0.30-1.13), and stroke (RR, 0.70; 95% CI, 0.47-1.04) at 1 year. We observed that the improvement in left ventricular ejection fraction was significantly greater in the patients without PPM (standardized mean difference, 0.22; 95% CI, 0.12-0.32). PPM implantation is not associated with increased risk of all-cause mortality, cardiovascular mortality, stroke, or myocardial infarction both at short- and long-term follow-up. However, PPM is associated with impaired left ventricular ejection fraction recovery post-transcatheter aortic valve replacement. © 2017 American Heart Association, Inc.

Maintenance of class III trifurcated molars versus implant placement in regenerated extraction sockets: long-term results of 2 cases.

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Zafiropoulos, Gregory-George K; di Prisco, Manuela Occipite; Deli, Giorgio; Hoffmann, Oliver

2011-03-01

Studies to date have reached differing conclusions regarding the long-term prognosis of teeth with class III furcation involvement. Replacement of such teeth with implants could be an alternative. This report compares the treatment outcomes of 2 cases with similar disease progression: 1 treated by implant therapy and 1 maintained with nonsurgical periodontal treatment. Two patients with advanced chronic periodontitis and class III furcation involvement of all molars were treated. Case 1 received a conservative periodontal and antibiotic treatment, followed by 15 years of maintenance. In case 2, the molars were extracted and replaced with implants, and the implants were observed for 7 years. Clinical attachment level (CAL), probing attachment level (PAL), bleeding on probing, plaque index, and periodontal pathogens were recorded. Despite good compliance of case 1, periodontal pathogens were not eliminated and tissue destruction was not halted. The PAL outcomes of case 2 improved over time; mean PAL loss reached 0.35 mm/y in the first 3 years and then decreased to 0.01 mm/y. While CAL outcomes did not change in case 2, case 1 showed increased CAL loss after 8 years. Based on the limited findings of this case report, extraction of molars with class III furcation involvement and subsequent implant placement may render a better predictability of treatment outcomes than nonsurgical periodontal therapy in the cases of infection with periodontal pathogens.

The effect of photodynamic therapy on pathogenic bacteria around peri-implant sulcus and in the cavity between abutment and implant after healing phase: A prospective clinical study.

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Zhou, Lin-Yi; Shi, Jun-Yu; Zhu, Yu; Qian, Shu-Jiao; Lai, Hong-Chang; Gu, Ying-Xin

2018-05-14

To compare levels of pathogens from peri-implant sulcus versus abutment screw cavities after photodynamic therapy. Twenty patients were included. Photodynamic therapy (PDT) was applied both in sulcus and cavities after sampling following suprastructures loading, and repeated after 2 weeks. Two samples each containing four paper points were collected for each implant at baseline, 2 weeks, 3 months: (i) peri-implant sulcus and (ii) abutment screw cavities. Seventy-five percent ethanol was applied in another 20 patients as the control group in the same way. qPCR was used to quantify periodontal pathogens: Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus mutans. PDT showed a better bacterial reduction than ethanol. P. g. and F. n. were most frequently detected, while less for S. m. P. gingivalis' proportion from both sites was significantly higher than the other two bacteria (P abutment screw cavities were always less than those from peri-implant sulcus and was significantly lower for total bacteria at 3 months (P abutment screw cavities significantly reduced at 3 months compared to baseline (P abutment screw cavities in the long run, suggesting PDT an effective way sterilizing inner surface of oral implant suprastrutures. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.

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Winkler, Heinz

2009-09-04

Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its

Choice of implant combinations in total hip replacement: systematic review and network meta-analysis.

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López-López, José A; Humphriss, Rachel L; Beswick, Andrew D; Thom, Howard H Z; Hunt, Linda P; Burston, Amanda; Fawsitt, Christopher G; Hollingworth, William; Higgins, Julian P T; Welton, Nicky J; Blom, Ashley W; Marques, Elsa M R

2017-11-02

Objective  To compare the survival of different implant combinations for primary total hip replacement (THR). Design  Systematic review and network meta-analysis. Data sources  Medline, Embase, The Cochrane Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and the EU Clinical Trials Register. Review methods  Published randomised controlled trials comparing different implant combinations. Implant combinations were defined by bearing surface materials (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, or metal-on-metal), head size (large ≥36 mm or small meta-analysis for revision. There was no evidence that the risk of revision surgery was reduced by other implant combinations compared with the reference implant combination. Although estimates are imprecise, metal-on-metal, small head, cemented implants (hazard ratio 4.4, 95% credible interval 1.6 to 16.6) and resurfacing (12.1, 2.1 to 120.3) increase the risk of revision at 0-2 years after primary THR compared with the reference implant combination. Similar results were observed for the 2-10 years period. 31 studies (2888 patients) were included in the analysis of Harris hip score. No implant combination had a better score than the reference implant combination. Conclusions  Newer implant combinations were not found to be better than the reference implant combination (metal-on-polyethylene (not highly cross linked), small head, cemented) in terms of risk of revision surgery or Harris hip score. Metal-on-metal, small head, cemented implants and resurfacing increased the risk of revision surgery compared with the reference implant combination. The results were consistent with observational evidence and were replicated in sensitivity analysis but were limited by poor reporting across studies. Systematic review registration  PROSPERO CRD42015019435. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence

The fabrication of bioresorbable implants for bone defects replacement using computer tomogram and 3D printing

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Kuznetsov, P. G.; Tverdokhlebov, S. I.; Goreninskii, S. I.; Bolbasov, E. N.; Popkov, A. V.; Kulbakin, D. E.; Grigoryev, E. G.; Cherdyntseva, N. V.; Choinzonov, E. L.

2017-09-01

The present work demonstrates the possibility of production of personalized implants from bioresorbable polymers designed for replacement of bone defects. The stages of creating a personalized implant are described, which include the obtaining of 3D model from a computer tomogram, development of the model with respect to shape of bone fitment bore using Autodesk Meshmixer software, and 3D printing process from bioresorbable polymers. The results of bioresorbable polymer scaffolds implantation in pre-clinical tests on laboratory animals are shown. The biological properties of new bioresorbable polymers based on poly(lactic acid) were studied during their subcutaneous, intramuscular, bone and intraosseous implantation in laboratory animals. In all cases, there was a lack of a fibrous capsule formation around the bioresorbable polymer over time. Also, during the performed study, conclusions were made on osteogenesis intensity depending on the initial state of bone tissue.

Influence of the Diameter of Dental Implants Replacing Single Molars: 3- to 6-Year Follow-Up.

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Mendonça, Jose Alfredo; Senna, Plinio Mendes; Francischone, Carlos Eduardo; Francischone Junior, Carlos Eduardo; Sotto-Maior, Bruno Salles

The aim of this study was to evaluate the influence of the implant diameter on marginal bone remodeling around dental implants replacing single molars after a follow-up period of 3 to 6 years. Patients who received dental implants with an external hexagon platform in healed sites to support a single metal-ceramic crown in the molar region were recalled to the office. The implantation sites and implant length information were recorded, and the implants were divided according to the implant diameter: regular (RP) or wide (WP). Each implant was assessed by digital periapical radiography, using a sensor holder for the paralleling technique. The marginal bone remodeling was determined as the distance from the implant platform to the first bone-to-implant contact, and the known implant length was used to calibrate the images in the computer software. The follow-up measurements were compared with those obtained from the radiograph taken at the time of prosthetic loading to determine the late bone remodeling. The independent t test was used to compare data. A total of 67 implants from 46 patients were evaluated with a mean follow-up period of 4.5 ± 1.0 years. The RP group comprised 36 implants from 29 patients (mean age: 58.3 ± 10.6 years), while 31 implants from 17 patients (mean age: 56.9 ± 11.5 years) were included in the WP group. The RP group presented lower survival rates (86.1%) than the WP group (100.0%). Similar marginal bone loss (P implants exhibited lower incidence failures, the bone levels were similar after the prosthetic loading around regular- and wide-diameter implants supporting single molar crowns.

Cardiac implantable electronic device and associated risk of infective endocarditis in patients undergoing aortic valve replacement

DEFF Research Database (Denmark)

Østergaard, Lauge; Valeur, Nana; Bundgaard, Henning

2017-01-01

Aims: Patients undergoing aortic valve replacement (AVR) are at increased risk of infective endocarditis (IE) as are patients with a cardiac implantable electronic device (CIED). However, few data exist on the IE risk after AVR surgery in patients with a CIED. Methods and results: Using the Danish...

Predictors of clinical outcome in total hip and knee replacement : a methodological appraisal of implants and patient factors

NARCIS (Netherlands)

Keurentjes, Johan Christiaan

2014-01-01

In this thesis, we studied both implants and patient and surgeon factors as predictors of clinical outcome after total hip and knee replacement. Additionally, we studied a number of methodological aspects of orthopaedic research, such as competing risks in estimating the probability of revision

Detection of five potentially periodontal pathogenic bacteria in peri-implant disease: A comparison of PCR and real-time PCR.

Science.gov (United States)

Schmalz, Gerhard; Tsigaras, Sandra; Rinke, Sven; Kottmann, Tanja; Haak, Rainer; Ziebolz, Dirk

2016-07-01

The aim of this study was to compare the microbial analysis methods of polymerase chain reaction (PCR) and real-time PCR (RT-PCR) in terms of detection of five selected potentially periodontal pathogenic bacteria in peri-implant disease. Therefore 45 samples of healthy, mucositis and peri-implantitis (n = 15 each) were assessed according to presence of the following bacteria using PCR (DNA-strip technology) and RT-PCR (fluorescent dye SYBR green-system): Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td), Tanerella forsythia (Tf), and Fusobacterium nucleatum (Fn). There were no significant correlations between the bacterial and disease patterns, so the benefit of using microbiological tests for the diagnosis of peri-implant diseases is questionable. Correlations between the methods were highest for Tf (Kendall's Tau: 0.65, Spearman: 0.78), Fn (0.49, 0.61) and Td (0.49, 0.59). For Aa (0.38, 0.42) and Pg (0.04, 0.04), lower correlation values were detected. Accordingly, conventional semi-quantitative PCR seems to be sufficient for analyzing potentially periodontal pathogenic bacterial species. Copyright © 2016 Elsevier Inc. All rights reserved.

Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

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Teeter, Matthew G.; Seslija, Petar; Milner, Jaques S.; Nikolov, Hristo N.; Yuan, Xunhua; Naudie, Douglas D. R.; Holdsworth, David W.

2013-05-01

An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements.

Quantification of in vivo implant wear in total knee replacement from dynamic single plane radiography

International Nuclear Information System (INIS)

Teeter, Matthew G; Naudie, Douglas D R; Holdsworth, David W; Seslija, Petar; Milner, Jaques S; Nikolov, Hristo N; Yuan Xunhua

2013-01-01

An in vivo method to measure wear in total knee replacements was developed using dynamic single-plane fluoroscopy. A dynamic, anthropomorphic total knee replacement phantom with interchangeable, custom-fabricated components of known wear volume was created, and dynamic imaging was performed. For each frame of the fluoroscopy data, the relative location of the femoral and tibial components were determined, and the apparent intersection of the femoral component with the tibial insert was used to calculate wear volume, wear depth, and frequency of intersection. No difference was found between the measured and true wear volumes. The precision of the measurements was ±39.7 mm 3 for volume and ±0.126 mm for wear depth. The results suggest the system is capable of tracking wear volume changes across multiple time points in patients. As a dynamic technique, this method can provide both kinematic and wear measurements that may be useful for evaluating new implant designs for total knee replacements. (paper)

A clinically translatable concept for periodontal ligament engineering around dental implants : The characterization of patient-friendly materials with optimal biomechanical properties

NARCIS (Netherlands)

de Jong, T.

2017-01-01

The periodontal ligament (PDL) connects the tooth to the alveolar bone. It functions as a shock absorber, forms a barrier against pathogens, and provides sensory information. These capacities are lost when the PDL is damaged, or when teeth are lost. Replacing missing teeth with dental implants is

New-Onset Atrial Fibrillation After Surgical Aortic Valve Replacement and Transcatheter Aortic Valve Implantation

DEFF Research Database (Denmark)

Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav

2015-01-01

Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...... (NOAF) is 31%-64% and 4%-32%, respectively. NOAF is independently associated with adverse events such as stroke, death, and increased length of hospital stay. Increasing the knowledge of predisposing factors, optimal postprocedural monitoring, and prophylactic antiarrhythmic and antithrombotic therapy...

New-onset atrial fibrillation after surgical aortic valve replacement and transcatheter aortic valve implantation

DEFF Research Database (Denmark)

Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav

2015-01-01

Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...... (NOAF) is 31%-64% and 4%-32%, respectively. NOAF is independently associated with adverse events such as stroke, death, and increased length of hospital stay. Increasing the knowledge of predisposing factors, optimal postprocedural monitoring, and prophylactic antiarrhythmic and antithrombotic therapy...

Multisite Infection with Mycobacterium abscessus after Replacement of Breast Implants and Gluteal Lipofilling.

Science.gov (United States)

Rüegg, Eva; Cheretakis, Alexandre; Modarressi, Ali; Harbarth, Stephan; Pittet-Cuénod, Brigitte

2015-01-01

Introduction. Medical tourism for aesthetic surgery is popular. Nontuberculous mycobacteria (NTM) occasionally cause surgical-site infections. As NTM grow in biofilms, implantations of foreign bodies are at risk. Due to late manifestation, infections occur when patients are back home, where they must be managed properly. Case Report. A 39-year-old healthy female was referred for acute infection of the right gluteal area. Five months before, she had breast implants replacement, abdominal liposuction, and gluteal lipofilling in Mexico. Three months postoperatively, implants were removed for NTM-infection in Switzerland. Adequate antibiotic treatment was stopped after seven days for drug-related hepatitis. At entrance, gluteal puncture for bacterial analysis was performed. MRI showed large subcutaneous collection. Debridement under general anaesthesia was followed by open wound management. Total antibiotic treatment was 20 weeks. Methods. Bacterial analysis of periprosthetic and gluteal liquids included Gram-stain plus acid-fast stain, and aerobic, anaerobic and mycobacterial cultures.  Results. In periprosthetic fluid, Mycobacterium abscessus, Propionibacterium, and Staphylococcus epidermidis were identified. The same M. abscessus strain was found gluteally. The gluteal wound healed within six weeks. At ten months' follow-up, gluteal asymmetry persists for deep scarring. Conclusion. This case presents major complications of multisite aesthetic surgery. Surgical-site infections in context of medical tourism need appropriate bacteriological investigations, considering potential NTM-infections.

Evaluation of aesthetics of implant-supported single-tooth replacements using different bone augmentation procedures : A prospective randomized clinical study

NARCIS (Netherlands)

Meijndert, Leo; Meijer, Henny J. A.; Stellingsma, Kees; Stegenga, Boudewijn; Raghoebar, Gerry M.

2007-01-01

Objectives: The aim of this study was to evaluate the aesthetics of implant-supported single-tooth replacements using different augmentation procedures in a prospective study with the use of an objective rating index and with a subjective patient questionnaire, and to compare the results with each

Update on Renal Replacement Therapy: Implantable Artificial Devices and Bioengineered Organs.

Science.gov (United States)

Attanasio, Chiara; Latancia, Marcela T; Otterbein, Leo E; Netti, Paolo A

2016-08-01

Recent advances in the fields of artificial organs and regenerative medicine are now joining forces in the areas of organ transplantation and bioengineering to solve continued challenges for patients with end-stage renal disease. The waiting lists for those needing a transplant continue to exceed demand. Dialysis, while effective, brings different challenges, including quality of life and susceptibility to infection. Unfortunately, the majority of research outputs are far from delivering satisfactory solutions. Current efforts are focused on providing a self-standing device able to recapitulate kidney function. In this review, we focus on two remarkable innovations that may offer significant clinical impact in the field of renal replacement therapy: the implantable artificial renal assist device (RAD) and the transplantable bioengineered kidney. The artificial RAD strategy utilizes micromachining techniques to fabricate a biohybrid system able to mimic renal morphology and function. The current trend in kidney bioengineering exploits the structure of the native organ to produce a kidney that is ready to be transplanted. Although these two systems stem from different technological approaches, they are both designed to be implantable, long lasting, and free standing to allow patients with kidney failure to be autonomous. However, for both of them, there are relevant issues that must be addressed before translation into clinical use and these are discussed in this review.

Four-unit fixed dental prostheses replacing the maxillary incisors supported by two narrow-diameter implants - a five-year case series.

Science.gov (United States)

Moráguez, Osvaldo; Vailati, Francesca; Grütter, Linda; Sailer, Irena; Belser, Urs C

2017-07-01

(1) To determine the survival rate of 10 four-unit fixed dental prostheses (FDPs) replacing the four maxillary incisors, supported by 20 narrow-diameter implants (NDIs), (2) to assess the incidence of mechanical and biological complications, and (3) to evaluate bone level changes longitudinally after final FDP insertion. Ten patients (six women, four men), mean age 49.4 ± 12.6 years, were treated with a four-unit anterior maxillary FDP (six screw-retained; four cemented). Biological parameters, eventual technical complications, radiographic measurements, and study casts were assessed at 1 (baseline), 3, and 5 years after implant placement. A multilevel logistic regression test was performed on clinical parameters and bone level changes (significance level P four-unit FDP to replace the four missing maxillary incisors may be considered a predictable treatment modality. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Pathology of Orthopedic Implant Failure Is Mediated by Innate Immune System Cytokines

Directory of Open Access Journals (Sweden)

Stefan Landgraeber

2014-01-01

Full Text Available All of the over 1 million total joint replacements implanted in the US each year are expected to eventually fail after 15–25 years of use, due to slow progressive subtle inflammation at the bone implant interface. This inflammatory disease state is caused by implant debris acting, primarily, on innate immune cells, that is, macrophages. This slow progressive pathological bone loss or “aseptic loosening” is a potentially life-threatening condition due to the serious complications in older people (>75 yrs of total joint replacement revision surgery. In some people implant debris (particles and ions from metals can influence the adaptive immune system as well, giving rise to the concept of metal sensitivity. However, a consensus of studies agrees that the dominant form of this response is due to innate reactivity by macrophages to implant debris where both danger (DAMP and pathogen (PAMP signalling elicit cytokine-based inflammatory responses. This paper discusses implant debris induced release of the cytokines and chemokines due to activation of the innate (and the adaptive immune system and the subsequent formation of osteolysis. Different mechanisms of implant-debris reactivity related to the innate immune system are detailed, for example, danger signalling (e.g., IL-1β, IL-18, IL-33, etc., toll-like receptor activation (e.g., IL-6, TNF-α, etc., apoptosis (e.g., caspases 3–9, bone catabolism (e.g., TRAP5b, and hypoxia responses (Hif1-α. Cytokine-based clinical and basic science studies are in progress to provide diagnosis and therapeutic intervention strategies.

The Pathology of Orthopedic Implant Failure Is Mediated by Innate Immune System Cytokines

Science.gov (United States)

Landgraeber, Stefan; Jäger, Marcus; Jacobs, Joshua J.; Hallab, Nadim James

2014-01-01

All of the over 1 million total joint replacements implanted in the US each year are expected to eventually fail after 15–25 years of use, due to slow progressive subtle inflammation at the bone implant interface. This inflammatory disease state is caused by implant debris acting, primarily, on innate immune cells, that is, macrophages. This slow progressive pathological bone loss or “aseptic loosening” is a potentially life-threatening condition due to the serious complications in older people (>75 yrs) of total joint replacement revision surgery. In some people implant debris (particles and ions from metals) can influence the adaptive immune system as well, giving rise to the concept of metal sensitivity. However, a consensus of studies agrees that the dominant form of this response is due to innate reactivity by macrophages to implant debris where both danger (DAMP) and pathogen (PAMP) signalling elicit cytokine-based inflammatory responses. This paper discusses implant debris induced release of the cytokines and chemokines due to activation of the innate (and the adaptive) immune system and the subsequent formation of osteolysis. Different mechanisms of implant-debris reactivity related to the innate immune system are detailed, for example, danger signalling (e.g., IL-1β, IL-18, IL-33, etc.), toll-like receptor activation (e.g., IL-6, TNF-α, etc.), apoptosis (e.g., caspases 3–9), bone catabolism (e.g., TRAP5b), and hypoxia responses (Hif1-α). Cytokine-based clinical and basic science studies are in progress to provide diagnosis and therapeutic intervention strategies. PMID:24891761

A personalized 3D-printed prosthetic joint replacement for the human temporomandibular joint: From implant design to implantation.

Science.gov (United States)

Ackland, David C; Robinson, Dale; Redhead, Michael; Lee, Peter Vee Sin; Moskaljuk, Adrian; Dimitroulis, George

2017-05-01

Personalized prosthetic joint replacements have important applications in cases of complex bone and joint conditions where the shape and size of off-the-shelf components may not be adequate. The objective of this study was to design, test and fabricate a personalized 3D-printed prosthesis for a patient requiring total joint replacement surgery of the temporomandibular joint (TMJ). The new 'Melbourne' prosthetic TMJ design featured a condylar component sized specifically to the patient and fixation screw positions that avoid potential intra-operative damage to the mandibular nerve. The Melbourne prosthetic TMJ was developed for a 58-year-old female recipient with end-stage osteoarthritis of the TMJ. The load response of the prosthesis during chewing and a maximum-force bite was quantified using a personalized musculoskeletal model of the patient's masticatory system developed using medical images. The simulations were then repeated after implantation of the Biomet Microfixation prosthetic TMJ, an established stock device. The maximum condylar stresses, screw stress and mandibular stress at the screw-bone interface were lower in the Melbourne prosthetic TMJ (259.6MPa, 312.9MPa and 198.4MPa, respectively) than those in the Biomet Microfixation device (284.0MPa, 416.0MPa and 262.2MPa, respectively) during the maximum-force bite, with similar trends also observed during the chewing bite. After trialing surgical placement and evaluating prosthetic TMJ stability using cadaveric specimens, the prosthesis was fabricated using 3D printing, sterilized, and implanted into the female recipient. Six months post-operatively, the prosthesis recipient had a normal jaw opening distance (40.0 mm), with no complications identified. The new design features and immediate load response of the Melbourne prosthetic TMJ suggests that it may provide improved clinical and biomechanical joint function compared to a commonly used stock device, and reduce risk of intra-operative nerve damage

Clinical application of single-tooth replacement with ankylos implant system

International Nuclear Information System (INIS)

Yang Xu; Liu Xue; Zhang Heng; Deng Yan; Guo Zhaozhong; Zhang Yufeng

2011-01-01

Objective: To evaluate the clinical effects of Ankylos implant system to restore the loss of single-tooth. Methods: 90 cases with loss of single-tooth were selected and treated with routinely two-stage surgery. When the patients presented with deficient alveolar ridge, guided bone regeneration (GBR), osteotome sinus floor elevation, lateral antrostomy surgery with simultaneous placement of implant were applied. They were restored with platinum ceramic crown. All the implants were followed up, and the records were kept about stability of the implant and abutment, the status of surrounding soft tissue, sealability of implant abutment junction and the marginal bone lossing through X-ray checking,and satisfaction of the patients to mastication and aspect of the restorations. The follow-up time was 1-2.5 years. Results: Among the cases,one case had peri-implant inflammation, and one case had porcelain dropped. No loosening occurred in the other implants and abuments. Implant abutment junction was sealed well. The marginal bone loss 1 year after final restoration was less than 1 mm. Soft tissue surrounding implants was healthy. The satisfaction rate was 98.9% (89/90). According to standard of implant success, 88 cases were successful, the 2.5-year cumulative success rate was 97.8%, 2 cases failed, and the failure rate was 2.2 %. Conclusion: A satisfactory treatment effects could be gotten by using Ankylos implant system to restore the loss of single-tooth. (authors)

Aortic valve replacement: is there an implant size variation across Europe?

Science.gov (United States)

Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A; Nashef, Samer A M; Aagaard, Jan; Moritz, Anton; Van Ingen, Gerrit; Chronidou, Fany; Palatianos, George; Alivizatos, Peter A; Stavridis, George T

2008-03-01

Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European countries. A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early mortality were collected. Group analysis by patient geographic distribution and by annular diameter of the prosthesis utilized was conducted. Patients with a manufacturer's labeled prosthesis size > or = 21 mm were assigned to the 'large' aortic size subset, while those with a prosthesis size < 21 mm were assigned to the 'small' aortic size subset. Effective orifice area indices were calculated for all patients to assess the geographic distribution of patient-prosthesis mismatch. Univariable and multivariable logistic regression analyses adjusting for possible confounding variables were performed. Prostheses with diameter < 21 mm were implanted at almost twice the rate in southern Europe compared to the north (56.4% versus 26.7%, p < 0.01). The mean valve size was also smaller in southern compared to northern European patients (21.6 +/- 2.1 mm versus 23.4 +/- 2.2 mm, p < 0.01). There were no regional differences in the distribution of either gender or BSA. In the multivariable model, south European patients were seven times more likely to receive a smaller-sized aortic valve (OR = 6.5, 95% CI = 4.82-8.83, p < 0.01), and thus the odds of developing patient-prosthesis mismatch were increased two-fold in southern European patients (OR = 1.9, 95% CI = 1.25-2.80, p = 0.02). However, neither geographic distribution nor valve size were significantly associated with operative mortality. The study results demonstrated

Mechanical characterization of structurally porous biomaterials built via additive manufacturing: experiments, predictive models, and design maps for load-bearing bone replacement implants.

Science.gov (United States)

Melancon, D; Bagheri, Z S; Johnston, R B; Liu, L; Tanzer, M; Pasini, D

2017-11-01

Porous biomaterials can be additively manufactured with micro-architecture tailored to satisfy the stringent mechano-biological requirements imposed by bone replacement implants. In a previous investigation, we introduced structurally porous biomaterials, featuring strength five times stronger than commercially available porous materials, and confirmed their bone ingrowth capability in an in vivo canine model. While encouraging, the manufactured biomaterials showed geometric mismatches between their internal porous architecture and that of its as-designed counterpart, as well as discrepancies between predicted and tested mechanical properties, issues not fully elucidated. In this work, we propose a systematic approach integrating computed tomography, mechanical testing, and statistical analysis of geometric imperfections to generate statistical based numerical models of high-strength additively manufactured porous biomaterials. The method is used to develop morphology and mechanical maps that illustrate the role played by pore size, porosity, strut thickness, and topology on the relations governing their elastic modulus and compressive yield strength. Overall, there are mismatches between the mechanical properties of ideal-geometry models and as-manufactured porous biomaterials with average errors of 49% and 41% respectively for compressive elastic modulus and yield strength. The proposed methodology gives more accurate predictions for the compressive stiffness and the compressive strength properties with a reduction of the average error to 11% and 7.6%. The implications of the results and the methodology here introduced are discussed in the relevant biomechanical and clinical context, with insight that highlights promises and limitations of additively manufactured porous biomaterials for load-bearing bone replacement implants. In this work, we perform mechanical characterization of load-bearing porous biomaterials for bone replacement over their entire design

Interventions for replacing missing teeth: treatment of peri-implantitis.

Science.gov (United States)

Esposito, Marco; Grusovin, Maria Gabriella; Worthington, Helen V

2012-01-18

One of the key factors for the long-term success of oral implants is the maintenance of healthy tissues around them. Bacterial plaque accumulation induces inflammatory changes in the soft tissues surrounding oral implants and it may lead to their progressive destruction (peri-implantitis) and ultimately to implant failure. Different treatment strategies for peri-implantitis have been suggested, however it is unclear which are the most effective. To identify the most effective interventions for treating peri-implantitis around osseointegrated dental implants. We searched the Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE. Handsearching included several dental journals. We checked the bibliographies of the identified randomised controlled trials (RCTs) and relevant review articles for studies outside the handsearched journals. We wrote to authors of all identified RCTs, to more than 55 dental implant manufacturers and an Internet discussion group to find unpublished or ongoing RCTs. No language restrictions were applied. The last electronic search was conducted on 9 June 2011. All RCTs comparing agents or interventions for treating peri-implantitis around dental implants. Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. We contacted the authors for missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes with 95% confidence intervals (CI). Heterogeneity was to be investigated including both clinical and methodological factors. Fifteen eligible trials were identified, but six were excluded. The following interventions were compared in the nine included studies: different non-surgical interventions (five trials); adjunctive treatments to non-surgical interventions (one trial); different surgical interventions (two trials

The flaws in the detail of an observational study on transcatheter aortic valve implantation versus surgical aortic valve replacement in intermediate-risks patients

NARCIS (Netherlands)

Barili, Fabio; Freemantle, Nick; Folliguet, Thierry; Muneretto, Claudio; de Bonis, Michele; Czerny, Martin; Obadia, Jean Francois; Al-Attar, Nawwar; Bonaros, Nikolaos; Kluin, Jolanda; Lorusso, Roberto; Punjabi, Prakash; Sadaba, Rafael; Suwalski, Piotr; Benedetto, Umberto; Böning, Andreas; Falk, Volkmar; Sousa-Uva, Miguel; Kappetein, Pieter A.; Menicanti, Lorenzo

2017-01-01

The PARTNER group recently published a comparison between the latest generation SAPIEN 3 transcatheter aortic valve implantation (TAVI) system (Edwards Lifesciences, Irvine, CA, USA) and surgical aortic valve replacement (SAVR) in intermediate-risk patients, apparently demonstrating superiority of

[Total cervical disk replacement--implant-specific approaches: keel implant (Prodisc-C intervertebral disk prosthesis)].

Science.gov (United States)

Korge, Andreas; Siepe, Christoph J; Heider, Franziska; Mayer, H Michael

2010-11-01

Dynamic intervertebral support of the cervical spine via an anterolateral approach using a modular artificial disk prosthesis with end-plate fixation by central keel fixation. Cervical median or mediolateral disk herniations, symptomatic cervical disk disease (SCDD) with anterior osseous, ligamentous and/or discogenic narrowing of the spinal canal. Cervical fractures, tumors, osteoporosis, arthrogenic neck pain, severe facet degeneration, increased segmental instability, ossification of posterior longitudinal ligament (OPLL), severe osteopenia, acute and chronic systemic, spinal or local infections, systemic and metabolic diseases, known implant allergy, pregnancy, severe adiposity (body mass index > 36 kg/m2), reduced patient compliance, alcohol abuse, drug abuse and dependency. Exposure of the anterior cervical spine using the minimally invasive anterolateral approach. Intervertebral fixation of retainer screws. Intervertebral diskectomy. Segmental distraction with vertebral body retainer and vertebral distractor. Removal of end-plate cartilage. Microscopically assisted decompression of spinal canal. Insertion of trial implant to determine appropriate implant size, height and position. After biplanar image intensifier control, drilling for keel preparation using drill guide and drill bit, keel-cut cleaner to remove bone material from the keel cut, radiologic control of depth of the keel cut using the corresponding position gauge. Implantation of original implant under lateral image intensifier control. Removal of implant inserter. Functional postoperative care and mobilization without external support, brace not used routinely, soft brace possible for 14 days due to postoperative pain syndromes. Implantation of 100 cervical Prodisc-C disk prostheses in 78 patients (average age 48 years) at a single center. Clinical and radiologic follow-up 24 months postoperatively. Significant improvement based on visual analog scale and Neck Disability Index. Radiologic

Failure rate of cemented and uncemented total hip replacements

DEFF Research Database (Denmark)

Makela, K. T.; Matilainen, M.; Pulkkinen, P.

2014-01-01

). Participants 347 899 total hip replacements performed during 1995-2011. Main outcome measures Probability of implant survival (Kaplan-Meier analysis) along with implant survival with revision for any reason as endpoint (Cox multiple regression) adjusted for age, sex, and diagnosis in age groups 55-64, 65......Objective To assess the failure rate of cemented, uncemented, hybrid, and reverse hybrid total hip replacements in patients aged 55 years or older. Design Register study. Setting Nordic Arthroplasty Register Association database (combined data from Sweden, Norway, Denmark, and Finland......-74, and 75 years or older. Results The proportion of total hip replacements using uncemented implants increased rapidly towards the end of the study period. The 10 year survival of cemented implants in patients aged 65 to 74 and 75 or older (93.8%, 95% confidence interval 93.6% to 94.0% and 95.9%, 95...

[Bentall operation combined with total arch replacement and stented elephant trunk implantation for serious Debakey I aortic dissecting aneurysm].

Science.gov (United States)

Gu, Tian-Xiang; Wang, Chun; Zhang, Yu-Hai

2008-12-01

To summarize the clinical experience of Bentall operation combined with total arch replacement and stented elephant trunk implantation for serious Debakey I aortic dissecting aneurysm. Twelve patients with serious Debakey I aortic dissecting aneurysm underwent surgical treatment from January 2005 to December 2007. There were 10 male and 2 female with the mean age of (40.1 +/- 9.5) years old. There were acute aortic dissection in 9 cases, chronic aortic dissection in 3 cases. The inner diameter of aorta was (5.3 +/- 1.8) cm. There were Marfan syndrome in 4 cases, aortic regurgitation in all cases, severely persistent chest pain in 9 cases, acute left heart failure in 8 cases, and cardiac tamponade in 4 cases. Bentall operations combined with total arch replacement and stented elephant trunk implantation were performed by using deep hypothermic circulatory arrest and antegrade selective cerebral perfusion in all cases. Urgent surgery underwent in 9 cases. The mean interval between the onset of aortic dissection and the accomplishment of surgery was (41.0 +/- 15.9) hours. Cardiopulmonary bypass time was (191 +/- 26) min, average cross clamp time was (134 +/- 31) min, and average deep hypothermic circulatory arrest time was (50.0 +/- 14.5) min. One patient died in hospital. The time stayed in ICU was 3 to 27 d. Mental disorder in 6 cases, hemi-paralysis in 1 case, amputation in 1 case, hemorrhage of anastomosis in 1 case, hemorrhage of alimentary tract in 1 case, and pleural effusion in 4 cases were recorded. Eleven cases were followed-up for 8 weeks to 36 months. There were no bending of the stents and no obstruction in the vascular prosthesis.No re-operation was needed. One case died 6 months postoperatively. Bentall operation combined with total arch replacement and stented elephant trunk implantation is safe and effective for serious Debakey I aortic dissecting aneurysm, while good organs protection and consummate cardiopulmonary bypass were taken.

Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material

Directory of Open Access Journals (Sweden)

Bloemer Wilhelm

2010-01-01

Full Text Available Abstract Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68 of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years and the average weight 102.3 kg (75 to 130 kg. The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck

Antibacterial TiO2Coating Incorporating Silver Nanoparticles by Micro arc Oxidation and Ion Implantation

International Nuclear Information System (INIS)

Zhang, P.; Zhang, Z.; Li, W.

2013-01-01

Infection associated with titanium implants remains the most common serious complication in hard tissue replacement surgery. Since such postoperative infections are usually difficult to cure, it is critical to find optimal strategies for preventing infections. In this study, TiO 2 coating incorporating silver (Ag) nanoparticles were fabricated on pure titanium by micro arc oxidation and ion implantation. The antibacterial activity was evaluated by exposing the specimens to Staphylococcus aureus and comparing the reaction of the pathogens to Ti-MAO-Ag with Ti-MAO controls. Ti-MAO-Ag clearly inhibited bacterial colonization more than the control specimen. The coating’s antibacterial ability was enhanced by increasing the dose of silver ion implantation, and Ti-MAO-Ag 20.0 had the best antibacterial ability. In addition, cytocompatibility was assessed by culturing cell colonies on the specimens. The cells grew well on both specimens. These findings indicate that surface modification by means of this process combining MAO and silver ion implantation is useful in providing antibacterial activity and exhibits cytocompatibility with titanium implants

Prosthetic valve sparing aortic root replacement: an improved technique.

Science.gov (United States)

Leacche, Marzia; Balaguer, Jorge M; Umakanthan, Ramanan; Byrne, John G

2008-10-01

We describe a modified surgical technique to treat patients with a previous history of isolated aortic valve replacement who now require aortic root replacement for an aneurysmal or dissected aorta. This technique consists of replacing the aortic root with a Dacron conduit, leaving intact the previously implanted prosthesis, and re-implanting the coronary arteries in the Dacron graft. Our technique differs from other techniques in that we do not leave behind any aortic tissue remnant and also in that we use a felt strip to obliterate any gap between the old sewing ring and the newly implanted graft. In our opinion, this promotes better hemostasis. We demonstrate that this technique is safe, feasible, and results in acceptable outcomes.

Diagnostic Imaging for Dental Implant Therapy

Directory of Open Access Journals (Sweden)

Aishwarya Nagarajan

2014-01-01

Full Text Available Dental implant is a device made of alloplastic (foreign material implanted into the jaw bone beneath the mucosal layer to support a fixed or removable dental prosthesis. Dental implants are gaining immense popularity and wide acceptance because they not only replace lost teeth but also provide permanent restorations that do not interfere with oral function or speech or compromise the self-esteem of a patient. Appropriate treatment planning for replacement of lost teeth is required and imaging plays a pivotal role to ensure a satisfactory outcome. The development of pre-surgical imaging techniques and surgical templates helps the dentist place the implants with relative ease. This article focuses on various types of imaging modalities that have a pivotal role in implant therapy.

Dental implants: A review.

Science.gov (United States)

Guillaume, B

2016-12-01

A high number of patients have one or more missing tooth and it is estimated that one in four American subjects over the age of 74 have lost all their natural teeth. Many options exist to replace missing teeth but dental implants have become one of the most used biomaterial to replace one (or more) missing tooth over the last decades. Contemporary dental implants made with titanium have been proven safe and effective in large series of patients. This review considers the main historical facts concerned with dental implants and present the different critical factors that will ensure a good osseo-integration that will ensure a stable prosthesis anchorage. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

In-situ photopolymerization and monitoring device for controlled shaping of tissue fillers, replacements, or implants

Science.gov (United States)

Schmocker, Andreas M.; Khoushabi, Azadeh; Bourban, Pierre-Etienne; Schizas, Constantin; Pioletti, Dominique; Moser, Christophe

2015-03-01

Photopolymerization is a common tool to harden materials initially in a liquid state. A surgeon can directly trigger the solidification of a dental implant or a bone or tissue filler simply by illumination. Traditionally, photopolymerization has been used mainly in dentistry. Over the last decade advances in material development including a wide range of biocompatible gel- and cement-systems open up a new avenue for in-situ photopolymerization. However, at the device level, surgical endoscopic probes are required. We present a miniaturized light probe where a photoactive material can be 1) mixed, pressurized and injected 2) photopolymerized or photoactivated and 3) monitored during the chemical reaction. The device enables surgeries to be conducted through a hole smaller than 1 mm in diameter. Beside basic injection mechanics, the tool consists of an optical fiber guiding the light required for photopolymerization and for chemical analysis. Combining photorheology and fluorescence spectroscopy, the current state of the photopolymerization is inferred and monitored in real time. Biocompatible and highly tuneable Poly-Ethylene-Glycol (PEG) hydrogels were used as the injection material. The device was tested on a model for intervertebral disc replacement. Gels were successfully implanted into a bovine caudal model and mechanically tested in-vitro during two weeks. The photopolymerized gel was evaluated at the tissue level (adherence and mechanical properties of the implant), at the cellular level (biocompatibility and cytotoxicity) and ergonomic level (sterilization procedure and feasibility study). This paper covers the monitoring aspect of the device.

Conduction Abnormalities and Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement Using the Repositionable LOTUS Device: The United Kingdom Experience.

Science.gov (United States)

Rampat, Rajiv; Khawaja, M Zeeshan; Hilling-Smith, Roland; Byrne, Jonathan; MacCarthy, Philip; Blackman, Daniel J; Krishnamurthy, Arvindra; Gunarathne, Ashan; Kovac, Jan; Banning, Adrian; Kharbanda, Raj; Firoozi, Sami; Brecker, Stephen; Redwood, Simon; Bapat, Vinayak; Mullen, Michael; Aggarwal, Suneil; Manoharan, Ganesh; Spence, Mark S; Khogali, Saib; Dooley, Maureen; Cockburn, James; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

2017-06-26

The authors report the incidence of pacemaker implantation up to hospital discharge and the factors influencing pacing rate following implantation of the LOTUS bioprosthesis (Boston Scientific, Natick, Massachusetts) in the United Kingdom. Transcatheter aortic valve replacement (TAVR) is associated with a significant need for permanent pacemaker implantation. Pacing rates vary according to the device used. The REPRISE II (Repositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System) trial reported a pacing rate of 29% at 30 days after implantation of the LOTUS device. Data were collected retrospectively on 228 patients who had the LOTUS device implanted between March 2013 and February 2015 across 10 centers in the United Kingdom. Twenty-seven patients (12%) had pacemakers implanted pre-procedure and were excluded from the analysis. Patients were aged 81.2 ± 7.7 years; 50.7% were male. The mean pre-procedural QRS duration was 101.7 ± 20.4 ms. More than one-half of the cohort (n = 111, 55%) developed new left bundle branch block (LBBB) following the procedure. Permanent pacemakers were implanted in 64 patients (32%) with a median time to insertion of 3.0 ± 3.4 days. Chief indications for pacing were atrioventricular (AV) block (n = 46, 72%), or LBBB with 1st degree AV block (n = 11, 17%). Amongst those who received a pacemaker following TAVR the pre-procedural electrocardiogram findings included: No conduction disturbance (n = 41, 64%); 1st degree AV block (n = 10, 16%); right bundle branch block (n = 6, 9%) and LBBB (n = 5, 8%). LBBB (but not permanent pacemaker) occurred more frequently in patients who had balloon aortic valvuloplasty before TAVR (odds ratio [OR]: 1.25; p = 0.03). Pre-procedural conduction abnormality (composite of 1st degree AV block, hemiblock, right bundle branch block, LBBB) was independently associated with the need for permanent pacemaker (OR: 2.54; p = 0.048). The absence of

An introduction to single implant abutments.

LENUS (Irish Health Repository)

Warreth, Abdulhadi

2013-01-01

This article is an introduction to single implant abutments and aims to provide basic information about abutments which are essential for all dental personnel who are involved in dental implantology. Clinical Relevance: This article provides a basic knowledge of implants and implant abutments which are of paramount importance, as replacement of missing teeth with oral implants has become a well-established clinical procedure.

Finite element analysis of the stress distributions in peri-implant bone in modified and standard-threaded dental implants

Directory of Open Access Journals (Sweden)

Serkan Dundar

2016-01-01

Full Text Available The aim of this study was to examine the stress distributions with three different loads in two different geometric and threaded types of dental implants by finite element analysis. For this purpose, two different implant models, Nobel Replace and Nobel Active (Nobel Biocare, Zurich, Switzerland, which are currently used in clinical cases, were constructed by using ANSYS Workbench 12.1. The stress distributions on components of the implant system under three different static loadings were analysed for the two models. The maximum stress values that occurred in all components were observed in FIII (300 N. The maximum stress values occurred in FIII (300 N when the Nobel Replace implant is used, whereas the lowest ones, in the case of FI (150 N loading in the Nobel Active implant. In all models, the maximum tensions were observed to be in the neck region of the implants. Increasing the connection between the implant and the bone surface may allow more uniform distribution of the forces of the dental implant and may protect the bone around the implant. Thus, the implant could remain in the mouth for longer periods. Variable-thread tapered implants can increase the implant and bone contact.

Peri-implant bone strains and micro-motion following in vivo service: a postmortem retrieval study of 22 tibial components from total knee replacements.

Science.gov (United States)

Mann, Kenneth A; Miller, Mark A; Goodheart, Jacklyn R; Izant, Timothy H; Cleary, Richard J

2014-03-01

Biological adaptation following placement of a total knee replacements (TKRs) affects peri-implant bone mineral density (BMD) and implant fixation. We quantified the proximal tibial bone strain and implant-bone micro-motion for functioning postmortem retrieved TKRs and assessed the strain/micro-motion relationships with chronological (donor age and time in service) and patient (body weight and BMD) factors. Twenty-two tibial constructs were functionally loaded to one body weight (60% medial/40% lateral), and the bone strains and tray/bone micro-motions were measured using a digital image correlation system. Donors with more time in service had higher bone strains (p = 0.044), but there was not a significant (p = 0.333) contribution from donor age. Donors with lower peri-implant BMD (p = 0.0039) and higher body weight (p = 0.0286) had higher bone strains. Long term implants (>11 years) had proximal bone strains 900 µϵ that were almost twice as high as short term (implants 570 µϵ. Micro-motion was greater for younger donors (p = 0.0161) and longer time in service (p = 0.0008). Increased bone strain with long term in vivo service could contribute to loosening of TKRs by failure of the tibial peri-implant bone. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

OpenAIRE

Kim, Chang-Soon; Duong, Hieu Pham; Park, Jung-Chul; Shin, Hyun-Seung

2016-01-01

Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-...

Decoronation followed by dental implants placement: fundamentals, applications and explanations

Science.gov (United States)

Consolaro, Alberto; Ribeiro, Paulo Domingos; Cardoso, Maurício A.; Miranda, Dario A. Oliveira; Salfatis, Monica

2018-01-01

ABSTRACT Dental arches areas with teeth presenting dentoalveolar ankylosis and replacement root resorption can be considered as presenting normal bone, in full physiological remodeling process; and osseointegrated implants can be successfully placed. Bone remodeling will promote osseointegration, regardless of presenting ankylosis and/or replacement root resorption. After 1 to 10 years, all dental tissues will have been replaced by bone. The site, angulation and ideal positioning in the space to place the implant should be dictated exclusively by the clinical convenience, associated with previous planning. One of the advantages of decoronation followed by dental implants placement in ankylosed teeth with replacement resorption is the maintenance of bone volume in the region, both vertical and horizontal. If possible, the buccal part of the root, even if thin, should be preserved in the preparation of the cavity for the implant, as this will maintain gingival tissues looking fully normal for long periods. In the selection of cases for decoronation, the absence of microbial contamination in the region - represented by chronic periapical lesions, presence of fistula, old unconsolidated root fractures and active advanced periodontal disease - is important. Such situations are contraindications to decoronation. However, the occurrence of dentoalveolar ankylosis and replacement resorption without contamination should neither change the planning for implant installation, nor the criteria for choosing the type and brand of dental implant to be used. Failure to decoronate and use dental implants has never been reported. PMID:29791693

Late complications in patients with Björk-Shiley and St. Jude Medical heart valve replacement.

Science.gov (United States)

Horstkotte, D; Körfer, R; Seipel, L; Bircks, W; Loogen, F

1983-09-01

Valve-related complications after Björk-Shiley mitral valve implantation (n = 475), aortic valve implantation (n = 424), or mitral-aortic valve implantation (n = 119) were compared with those after St. Jude Medical mitral valve replacement (n = 173), aortic valve replacement (n = 152), or mitral-aortic valve replacement (n = 69). All patients were placed on anticoagulant therapy with phenprocoumon early after operation. All patients had a comparable follow-up time of approximately 23 months, which showed that cumulative thromboembolic rates were significantly higher after St. Jude valve implantation than after Björk-Shiley valve implantation. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2.2%), or prosthetic valve endocarditis with perivalvular regurgitation (0.46%). One Björk-Shiley mitral valve prosthesis had to be replaced because of fracture of the outlet strut. Without significant intergroup differences, hemorrhage due to anticoagulant treatment was the most frequent complication. Thromboembolic complications were significantly more frequent after Björk-Shiley mitral, aortic, and double valve replacements than after St. Jude valve implantation. This may lead to consideration of changes in the prophylaxis of thrombus formations in the St. Jude valve, especially in aortic valve replacements, in patients with sinus rhythm.

Treatment planning: implant-supported partial overdentures.

Science.gov (United States)

Chee, Winston W L

2005-04-01

When multiple anterior teeth are missing, many options of replacement are available. Traditionally, the choice was between a fixed or removable prostheses. Today, with the predictability of dental implants, the options of tooth replacement range from removable partial dentures to implant-supported fixed prostheses. The choice of which restoration that will best provide occlusion and esthetics depends on multiple factors including the number and location of missing teeth, the residual ridge form in relation to the replacement teeth, the relationship of the maxillary and mandibular anterior teeth, the condition of teeth adjacent to the edentulous span, the amount of bone available for implant placement, the patients "smile line" and display of teeth, lip support, and financial constraints. When there is minimal loss of the ridge contour, restorations that emerge from the ridge are the most functional and esthetic restorations, adhesive-type fixed partial dentures, conventional fixed partial dentures, and implant-supported restorations can be indicated with the choice of restoration dependent on a risk benefit and cost benefit analysis. When there is a loss of ridge contour due to residual ridge resorption or trauma, the decision becomes more complex as not only does the tooth structure need to be replaced, the ridge form also has to be replaced. (Figures 1 and 2). This can be assessed clinically as illustrated by Figures 1 and 2 where a dis crepancy in arch form and ridge form in relation to the adjacent teeth and/or opposing arch can be observed. Other considerations are lip support and display of the teeth when smiling. This article presents a case and rationale for implant-supported par tial overdentures. Many authors have written on the merits of com plete overdentures. The complete overdenture has proven to be an improvement over conventional complete prostheses with respect to chewing efficiency, patient comfort and satisfaction. In partial edentulism, the

Principles of human joint replacement design and clinical application

CERN Document Server

Buechel, Frederick F

2015-01-01

This book is written for the users and designers of joint replacements. In its second extended edition it conveys to the reader the knowledge accumulated by the authors during their forty year effort on the development of replacement devices for the lower limb for the purpose of aiding the reader in their design and evaluation of joint replacement devices. The early chapters describe the engineering, scientific and medical principles needed for replacement joint evaluation. One must understand the nature and performance of the materials involved and their characteristics in vivo, i.e. the response of the body to implant materials. It is also essential to understand the response of the implants to applied loading and motion, particularly in the hostile physiological environment. A chapter describes the design methodology now required for joint replacement in the USA and EU countries. The remaining chapters provide a history of joint replacement, an evaluation of earlier and current devices and sample case hist...

Principles of Human Joint Replacement Design and Clinical Application

CERN Document Server

Buechel, Frederick F

2012-01-01

Drs. Buechel, an orthopaedic surgeon, and Pappas, a professor of Mechanical Engineering, are the designers of several successful joint replacement systems. The most well-known of these is the pioneering LCS knee replacement. They have written this book for the users and designers of joint replacements. It is an attempt to convey to the reader the knowledge accumulated by the authors during their thirty five year effort on the development of replacement devices for the lower limb for the purpose of aiding the reader in their design and evaluation of joint replacement devices. The early chapters describe the engineering, scientific and medical principles needed for replacement joint evaluation. One must understand the nature and performance of the materials involved and their characteristics in vivo, i.e. the response of the body to implant materials. It is also essential to understand the response of the implants to applied loading and motion, particularly in the hostile physiological environment. A chapter de...

Zirconia implants and peek restorations for the replacement of upper molars

Directory of Open Access Journals (Sweden)

José María Parmigiani-Izquierdo

2017-02-01

Full Text Available Abstract Background One of the disadvantages of the zirconia implants is the lack of elasticity, which is increased with the use of ceramic or zirconia crowns. The consequences that could result from this lack of elasticity have led to the search for new materials with improved mechanical properties. Case presentation A patient who is a 45-year-old woman, non-smoker and has no medical record of interest with a longitudinal fracture in the palatal root of molar tooth 1.7 and absence of tooth 1.6 was selected in order to receive a zirconia implant with a PEEK-based restoration and a composite coating. The following case report describes and analyses treatment with zirconia implants in molars following a flapless surgical technique. Zirconia implants are an alternative to titanium implants in patients with allergies or who are sensitive to metal alloys. However, one of the disadvantages that they have is their lack of elasticity, which increases with the use of ceramic or zirconia crowns. The consequences that can arise from this lack of elasticity have led to the search for new materials with better mechanical properties to cushion occlusal loads. PEEK-based restoration in implant prosthetics can compensate these occlusal forces, facilitating cushioning while chewing. Conclusion This procedure provides excellent elasticity and resembles natural tooth structure. This clinical case suggests that PEEK restorations can be used in zirconia implants in dentistry.

Embedded piezoelectrics for sensing and energy harvesting in total knee replacement units

Science.gov (United States)

Wilson, Brooke E.; Meneghini, Michael; Anton, Steven R.

2015-04-01

The knee replacement is the second most common orthopedic surgical intervention in the United States, but currently only 1 in 5 knee replacement patients are satisfied with their level of pain reduction one year after surgery. It is imperative to make the process of knee replacement surgery more objective by developing a data driven approach to ligamentous balance, which increases implant life. In this work, piezoelectric materials are considered for both sensing and energy harvesting applications in total knee replacement implants. This work aims to embed piezoelectric material in the polyethylene bearing of a knee replacement unit to act as self-powered sensors that will aid in the alignment and balance of the knee replacement by providing intraoperative feedback to the surgeon. Postoperatively, the piezoelectric sensors can monitor the structural health of the implant in order to perceive potential problems before they become bothersome to the patient. Specifically, this work will present on the use of finite element modeling coupled with uniaxial compression testing to prove that piezoelectric stacks can be utilized to harvest sufficient energy to power sensors needed for this application.

Attitudes of general dental practitioners towards implant dentistry in an environment with widespread provision of implant therapy.

Science.gov (United States)

Lang-Hua, Bich Hue; Lang, Niklaus P; Lo, Edward C M; McGrath, Colman P J

2013-03-01

To determine attitudes of general dental practitioners in a community where provision dental implants is a well-known treatment modality; and to identify variations in the attitudes with respect to dentists' factors, training factors and implant provision factors. A questionnaire survey to a random sample of registered dentists In Hong Kong was performed. Attitudes towards implant dentistry with respect to (i) perceived superiority of implant therapy, (ii) perceived outcomes of dental implant therapy, (iii) perceived complications & maintenance issues and (iv) placement issues were ascertained. In addition, information was collected on dentists' factors, training factors and implant provision factors. Variations in attitudes towards implant dentistry were explored in bivariate and regression analyses. Among eligible practitioners (n = 246), the response rate was 46.3%. Dentists perceived implants to be superior to conventional prostheses for the replacement of a single missing posterior tooth (80%, 67) and likewise, for the replacement of a single missing anterior tooth (67%, 67), P attitudes with respect to attitudes exists with respect to dentists' factors (years in practice [P attitudes are not wholly in line with evidence-based knowledge. Variations in their attitudes existed with respect to dentist factors, training and experience issues. © 2012 John Wiley & Sons A/S.

Short dental implants: an emerging concept in implant treatment.

Science.gov (United States)

Al-Hashedi, Ashwaq Ali; Taiyeb Ali, Tara Bai; Yunus, Norsiah

2014-06-01

Short implants have been advocated as a treatment option in many clinical situations where the use of conventional implants is limited. This review outlines the effectiveness and clinical outcomes of using short implants as a valid treatment option in the rehabilitation of edentulous atrophic alveolar ridges. Initially, an electronic search was performed on the following databases: Medline, PubMed, Embase, Cochrane Database of Systematic Reviews, and DARE using key words from January 1990 until May 2012. An additional hand search was included for the relevant articles in the following journals: International Journal of Oral and Maxillofacial Implants, Clinical Oral Implants Research, Journal of Clinical Periodontology, International Journal of Periodontics, Journal of Periodontology, and Clinical Implant Dentistry and Related Research. Any relevant papers from the journals' references were hand searched. Articles were included if they provided detailed data on implant length, reported survival rates, mentioned measures for implant failure, were in the English language, involved human subjects, and researched implants inserted in healed atrophic ridges with a follow-up period of at least 1 year after implant-prosthesis loading. Short implants demonstrated a high rate of success in the replacement of missing teeth in especially atrophic alveolar ridges. The advanced technology and improvement of the implant surfaces have encouraged the success of short implants to a comparable level to that of standard implants. However, further randomized controlled clinical trials and prospective studies with longer follow-up periods are needed.

Antibiotic resistance in human peri-implantitis microbiota

NARCIS (Netherlands)

Rams, Thomas E.; Degener, John E.; van Winkelhoff, Arie J.

ObjectivesBecause antimicrobial therapy is often employed in the treatment of infectious dental implant complications, this study determined the occurrence of in vitro antibiotic resistance among putative peri-implantitis bacterial pathogens. MethodsSubmucosal biofilm specimens were cultured from

Number of implants for mandibular implant overdentures: a systematic review

Science.gov (United States)

Lee, Jeong-Yol; Kim, Ha-Young; Bryant, S. Ross

2012-01-01

PURPOSE The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction. MATERIALS AND METHODS A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants. RESULTS Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants. CONCLUSION The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants. PMID:23236572

Surgical Templates for Dental Implant Positioning; Current ...

African Journals Online (AJOL)

Since the mid‑20th century, there has been an increase in interest in the implant process for the replacement of missing teeth. Branemark ... Ideal placement of the implant facilitates the establishment of favorable forces on the implants and the prosthetic component as well as ensures an aesthetic outcome. Therefore, it is ...

An in vitro study to compare the accuracy of the master cast fabricated by four different transfer impression techniques for single-tooth implant replacement.

Science.gov (United States)

Lahori, Manesh; Nagrath, Rahul; Agrawal, Prateek

2014-03-01

Single tooth implant retained crowns have become a recognized technique for the replacement of the missing teeth. With the predictable integration of implants, the emphasis is shifted towards precise prosthesis. Minor movement of the impression coping retained inside the impression material can occur during all the procedures, leading to the three-dimensional spatial inaccuracies in the master casts. Therefore, the present study was undertaken with the purpose to evaluate the accuracy of single-tooth implant impression techniques using four different impression copings, so as to obtain a precise definitive cast for a single-unit implant restoration. A maxillary acrylic resin model with a standard single implant in the first molar region was used to simulate a clinical situation. A total of 60 impressions were made with polyvinylsiloxane impression material, which were divided into four groups of 15 impressions each. Group I used non-modified square impression coping, while in group II, III and IV square impression coping were modified differently. Master casts fabricated for all the groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model. The master casts obtained with the roughened and adhesive-coated impression copings showed a lower amount of rotational movement than the masters casts achieved with the non-modified impression copings. Hence, the clinician should use sandblasted and adhesive coated impression copings to achieve a more accurate and precise orientation of the implant replicas in the laboratory master casts in single-tooth implant restorations.

Tooth replacements in young adults with severe hypodontia: Orthodontic space closure, dental implants, and tooth-supported fixed dental prostheses. A follow-up study.

Science.gov (United States)

Hvaring, Christina L; Øgaard, Bjørn; Birkeland, Kari

2016-10-01

Children with severe hypodontia have a substantial impairment of their dental health starting early in life. The purpose of this study was to describe types and locations of substitutes for missing teeth in patients with severe hypodontia and to compare the crown and soft tissue morphologies of orthodontic space closure, dental implants, and tooth-supported fixed dental prostheses for replacing teeth in the anterior region. Fifty patients missing 6 or more teeth and aged 18 years or older (mean age, 25.6 years) took part in a follow-up study. The patients were examined clinically with panoramic radiographs and clinical photographs. Crown and soft tissue variables (mucosal discoloration, crown morphology, color, and papilla index) were compared for orthodontic space closure, dental implant fixtures, and fixed dental prostheses. Dental implants, orthodontic space closure, and retaining deciduous teeth were the most commonly prescribed treatments. Persisting deciduous teeth showed a good survival rate at the follow-up examination. Mucosal discoloration was seen only for implant fixtures and was evident for almost all fixtures in the anterior mandible and two thirds of those in the anterior maxilla. The papilla index scored poorer for both implant fixtures and fixed dental prostheses compared with orthodontic space closure. Dental implants in the anterior region proved to be an inadequate treatment modality in patients with severe hypodontia because of pronounced mucosal discoloration. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

A cardiac implantable device infection by Raoultella planticola in an immunocompromized patient.

Science.gov (United States)

Adjodah, Chandra; D'Ivernois, Chistophe; Leyssene, David; Berneau, Jean-Baptiste; Hemery, Yann

2017-02-01

Introduction. Infection of cardiac implantable electronic devices is a severe condition associated with high mortality, particularly in patients who are dependent upon heart-pacing devices. Staphylococci are found in 70 % of reported cases. Case presentation. We report the case of a cardiac-pacemaker infection in a 79-year-old man, cumulating a history of rheumatoid arthritis treated by corticosteroids and methotrexate by a recently identified micro-organism: Raoultella planticola . He presented local signs of infection on his VVI pacemaker implantation site and underwent urgent pocket device replacement under cefamandole antibioprophylaxis. On incision thick pus oozed out. It was necessary to perform a complete hardware extraction comprising the pulse generator and the ancient lead. Pus was inoculated into aerobic and anaerobic culture vials and Gram staining unveiled Gram-negative rods. Microbiology analysis identified the organism as R. planticola. A new pacing device was inserted on the contrlateral pectoral region. Ciprofloxacin enabled full recovery. A literature review concerning this pathogen revealed that it is involved in severe infections such as bloodstream infections, peritonitis, cellulitis, pneumonia and lung abscesses, and urinary tract infections. In these case reports, underlying co-morbidities were identified such as solid active neoplasia, recent chemotherapy, corticosteroids, solid-organ-recipient patients and recent open surgery. Conclusion. R. planticola is a serious emerging pathogen and contributes to the burden of various infectious conditions. Its pathogenicity and occurrence should be known by clinicians and a high level of awareness is necessary to precisely identify it provide the correct antibiotic regimen.

In Vitro Laser Treatment Platform Construction with Dental Implant Thread Surface on Bacterial Adhesion for Peri-Implantitis

Directory of Open Access Journals (Sweden)

Hsien-Nan Kuo

2017-01-01

Full Text Available This study constructs a standard in vitro laser treatment platform with dental implant thread surface on bacterial adhesion for peri-implantitis at different tooth positions. The standard clinical adult tooth jaw model was scanned to construct the digital model with 6 mm bone loss depth on behalf of serious peri-implantitis at the incisor, first premolar, and first molar. A cylindrical suite connected to the implant and each tooth root in the jaw model was designed as one experimental unit set to allow the suite to be replaced for individual bacterial adhesion. The digital peri-implantitis and suite models were exported to fulfill the physical model using ABS material in a 3D printer. A 3 mm diameter specimen implant on bacterial adhesion against Escherichia coli was performed for gram-negative bacteria. An Er:YAG laser, working with a chisel type glass tip, was moved from the buccal across the implant thread to the lingual for about 30 seconds per sample to verify the in vitro laser treatment platform. The result showed that the sterilization rate can reach 99.3% and the jaw model was not damaged after laser irradiation testing. This study concluded that using integrated image processing, reverse engineering, CAD system, and a 3D printer to construct a peri-implantitis model replacing the implant on bacterial adhesion and acceptable sterilization rate proved the feasibility of the proposed laser treatment platform.

Saturation and isotopic replacement of deuterium in low-Z material

International Nuclear Information System (INIS)

Doyle, B.L.; Wampler, W.R.; Brice, D.K.; Picraux, S.T.

1980-01-01

The saturation and replacement of hydrogen isotopes implanted into TiC, TiB 2 , VB 2 , B 4 C, B, Si, and C has been examined experimentally and modeled theoretically. The deuterium saturation concentrations for these materials varied from .16 to .57. A new isotopic replacement model is presented which predicts isotopic trapping and exchange on the basis of the depth dependence of the implanted ions and the experimentally determined hydrogen saturation concentration. Our results indicate that, for these materials used as coatings on components in a D-T fueled tokamak, T recovery by ion induced replacement with H or D should be feasible and that T buildup will be at tolerable levels

Long-term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats.

Science.gov (United States)

Avivi-Arber, Limor; Lee, Jye-Chang; Sood, Mandeep; Lakschevitz, Flavia; Fung, Michelle; Barashi-Gozal, Maayan; Glogauer, Michael; Sessle, Barry J

2015-11-01

Tooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face-M1) and adjacent primary somatosensory cortex (face-S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face-M1 and face-S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1-2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS-evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P rats. These novel findings suggest that face-M1 and adjacent face-S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants. © 2015 Wiley Periodicals, Inc.

Optimal insemination and replacement decisions to minimize the cost of pathogen-specific clinical mastitis in dairy cows.

Science.gov (United States)

Cha, E; Kristensen, A R; Hertl, J A; Schukken, Y H; Tauer, L W; Welcome, F L; Gröhn, Y T

2014-01-01

Mastitis is a serious production-limiting disease, with effects on milk yield, milk quality, and conception rate, and an increase in the risk of mortality and culling. The objective of this study was 2-fold: (1) to develop an economic optimization model that incorporates all the different types of pathogens that cause clinical mastitis (CM) categorized into 8 classes of culture results, and account for whether the CM was a first, second, or third case in the current lactation and whether the cow had a previous case or cases of CM in the preceding lactation; and (2) to develop this decision model to be versatile enough to add additional pathogens, diseases, or other cow characteristics as more information becomes available without significant alterations to the basic structure of the model. The model provides economically optimal decisions depending on the individual characteristics of the cow and the specific pathogen causing CM. The net returns for the basic herd scenario (with all CM included) were $507/cow per year, where the incidence of CM (cases per 100 cow-years) was 35.6, of which 91.8% of cases were recommended for treatment under an optimal replacement policy. The cost per case of CM was $216.11. The CM cases comprised (incidences, %) Staphylococcus spp. (1.6), Staphylococcus aureus (1.8), Streptococcus spp. (6.9), Escherichia coli (8.1), Klebsiella spp. (2.2), other treated cases (e.g., Pseudomonas; 1.1), other not treated cases (e.g., Trueperella pyogenes; 1.2), and negative culture cases (12.7). The average cost per case, even under optimal decisions, was greatest for Klebsiella spp. ($477), followed by E. coli ($361), other treated cases ($297), and other not treated cases ($280). This was followed by the gram-positive pathogens; among these, the greatest cost per case was due to Staph. aureus ($266), followed by Streptococcus spp. ($174) and Staphylococcus spp. ($135); negative culture had the lowest cost ($115). The model recommended treatment for

Management of dental implant fractures. A case history.

Science.gov (United States)

Al Quran, Firas A M; Rashan, Bashar A; Al-Dwairi, Ziad N

2009-01-01

The widespread use of endosseous osseointegrated implants to replace missing natural teeth increases the chances of implant complications and failures, despite the high initial success rate reported in the literature. Implant fracture is one possible complication that results in ultimate failure of the dental implant. Such a complication poses a management crisis even for the most experienced clinician. This article reports on a case of implant fracture, its possible causes, and how the case was managed.

Microstructure and mechanical properties of open-cellular biomaterials prototypes for total knee replacement implants fabricated by electron beam melting.

Science.gov (United States)

Murr, L E; Amato, K N; Li, S J; Tian, Y X; Cheng, X Y; Gaytan, S M; Martinez, E; Shindo, P W; Medina, F; Wicker, R B

2011-10-01

Total knee replacement implants consisting of a Co-29Cr-6Mo alloy femoral component and a Ti-6Al-4V tibial component are the basis for the additive manufacturing of novel solid, mesh, and foam monoliths using electron beam melting (EBM). Ti-6Al-4V solid prototype microstructures were primarily α-phase acicular platelets while the mesh and foam structures were characterized by α(')-martensite with some residual α. The Co-29Cr-6Mo containing 0.22% C formed columnar (directional) Cr(23)C(6) carbides spaced ~2 μm in the build direction, while HIP-annealed Co-Cr alloy exhibited an intrinsic stacking fault microstructure. A log-log plot of relative stiffness versus relative density for Ti-6Al-4V and Co-29Cr-6Mo open-cellular mesh and foams resulted in a fitted line with a nearly ideal slope, n = 2.1. A stress shielding design graph constructed from these data permitted mesh and foam implant prototypes to be fabricated for compatible bone stiffness. Copyright © 2011 Elsevier Ltd. All rights reserved.

Carbon offers advantages as implant material in human body

Science.gov (United States)

Benson, J.

1969-01-01

Because of such characteristics as high strength and long-term biocompatability, aerospace carbonaceous materials may be used as surgical implants to correct pathological conditions in the body resulting from disease or injury. Examples of possible medical uses include bone replacement, implantation splints and circulatory bypass implants.

Surface modifications of dental implants.

Science.gov (United States)

Stanford, C M

2008-06-01

Dental implant surface technologies have been evolving rapidly to enhance a more rapid bone formation on their surface and hold a potential to increase the predictability of expedited implant therapy. While implant outcomes have become highly predictable, there are sites and conditions that result in elevated implant loss. This paper reviews the impact of macro-retentive features which includes approaches to surface oxide modification, thread design, press-fit and sintered-bead technologies to increase predictability of outcomes. Implant designs that lead to controlled lateral compression of the bone can improve primary stability as long as the stress does not exceed the localized yield strength of the cortical bone. Some implant designs have reduced crestal bone loss by use of multiple cutting threads that are closely spaced, smoothed on the tip but designed to create a hoop-stress stability of the implant as it is completely seated in the osteotomy. Following the placement of the implant, there is a predictable sequence of bone turnover and replacement at the interface that allows the newly formed bone to adapt to microscopic roughness on the implant surface, and on some surfaces, a nanotopography (<10(-9) m scale) that has been shown to preferably influence the formation of bone. Newly emerging studies show that bone cells are exquisitely sensitive to these topographical features and will upregulate the expression of bone related genes for new bone formation when grown on these surfaces. We live in an exciting time of rapid changes in the modalities we can offer patients for tooth replacement therapy. Given this, it is our responsibility to be critical when claims are made, incorporate into our practice what is proven and worthwhile, and to continue to support and provide the best patient care possible.

Influence of implant position on clinical crown length and peri-implant soft tissue dimensions at implant-supported single crowns replacing maxillary central incisors

DEFF Research Database (Denmark)

Peng, Min; Fei, Wei; Hosseini, Mandana

2013-01-01

The aims of the present study were to evaluate the influence of implant position on clinical crown length and marginal soft tissue dimensions at implant-supported single crowns of maxillary central incisors, and to validate the papilla index score (PIS). Twenty-five patients, who had lost one of ...... abutments and did not necessarily result in an increased crown length. The distal implant papilla heightwas obviously shorter, althoughthe mesial papilla height was similar to thatof the healthy dentition.The papilla index score was tested to be a valid index for papilla fill....

Single-tooth replacement by osseointegrated Astra Tech dental implants: a 2-year report

DEFF Research Database (Denmark)

Karlsson, U; Gotfredsen, K; Olsson, C

1998-01-01

This study presents the outcome of single-tooth restorations supported by Astra Tech single-tooth implants followed for 2 years. Forty-seven implants were placed in the same number of patients. Forty-three patients attended the second recall visit, and none of the evaluated implants have been...

Implant-supported prostheses versus conventional permanent and removable dentures

Directory of Open Access Journals (Sweden)

Koszuta Agnieszka

2014-06-01

Full Text Available Social, economic and technological progress results in an increasing range of treatment and rehabilitation methods for patients with partial or complete edentulism. The role of the dentist is to inform the patient about the full range of available missing teeth treatment options leading to complete rehabilitation of the masticatory organ in agreement with the patient’s aesthetic and functional expectations. The aim of the paper was to identify the type of prostheses used by patients before opting for implantsupported teeth replacements, according to the patients’ age, sex, marital status, place of residence and education. The study covered 464 patients, women and men, aged 20-74, treated with dental implants. The patients answered questions in an anonymous questionnaire. The influence of the prosthetic replacement type according to age and marital status was highly statistically significant, whereas it was statistically significant according to sex, place of residence and education. The female respondents who previously used tissue-borne complete or partial dentures opted for implant treatment more frequently. The respondents younger than 40 and between 40-60 years of age who did not previously used any prosthetic replacements opted for implant treatment more frequently. The respondents who did not use any prosthetic replacements decided to undergo implant treatment most frequently, regardless of their marital status, education and place of residence. The patients opted for implant treatment to improve their quality of life, despite the high cost of such therapy.

Dental implants in growing children

Directory of Open Access Journals (Sweden)

S K Mishra

2013-01-01

Full Text Available The replacement of teeth by implants is usually restricted to patients with completed craniofacial growth. The aim of this literature review is to discuss the use of dental implants in normal growing patients and in patients with ectodermal dysplasia and the influence of maxillary and mandibular skeletal and dental growth on the stability of those implants. It is recommended that while deciding the optimal individual time point of implant insertion, the status of skeletal growth, the degree of hypodontia, and extension of related psychological stress should be taken into account, in addition to the status of existing dentition and dental compliance of a pediatric patient.

A new system of implant abutment connection: how to improve a two piece implant system sealing.

Science.gov (United States)

Grecchi, F; DI Girolamo, M; Cura, F; Candotto, V; Carinci, F

2017-01-01

Implant dentistry has become one of the most successful dentistry techniques for replacing missing teeth. The success rate of implant dentistry is above 80%. However, peri-implantitis is a later complication of implant dentistry that if untreated, can lead to implant loss. One of the hypotized causes of peri-implantis is the bacterial leakage at the level of implant-abutment connection. Bacterial leakage is favored to the presence of a micro gap at the implant-abutment interface, allowing microorganisms to penetrate and colonize the inner part of the implant leading to biofilm accumulation and consequently to peri-implantitis development. To identify the capability of the implant to protect the internal space from the external environment, the passage of genetically modified Escherichia coli across implant-abutment interface was evaluated. Implants were immerged in a bacterial culture for twenty-four hours and then bacteria amount was measured inside implant-abutment interface with Real-time PCR. Bacteria were detected inside all studied implants, with a median percentage of 9%. The reported results are better to those of previous studies carried out on different implant systems. Until now, none implant-abutment system has been proven to seal the gap between implant and abutment.

Heart valve replacements with regenerative capacity

NARCIS (Netherlands)

Dijkman, P.E.; Fioretta, E.S.; Frese, L.; Pasqualini, F.S.; Hoerstrup, S.P.

2016-01-01

The incidence of severe valvular dysfunctions (e.g., stenosis and insufficiency) is increasing, leading to over 300,000 valves implanted worldwide yearly. Clinically used heart valve replacements lack the capacity to grow, inherently requiring repetitive and high-risk surgical interventions during

[Carbon fiber-reinforced plastics as implant materials].

Science.gov (United States)

Bader, R; Steinhauser, E; Rechl, H; Siebels, W; Mittelmeier, W; Gradinger, R

2003-01-01

Carbon fiber-reinforced plastics have been used clinically as an implant material for different applications for over 20 years.A review of technical basics of the composite materials (carbon fibers and matrix systems), fields of application,advantages (e.g., postoperative visualization without distortion in computed and magnetic resonance tomography), and disadvantages with use as an implant material is given. The question of the biocompatibility of carbon fiber-reinforced plastics is discussed on the basis of experimental and clinical studies. Selected implant systems made of carbon composite materials for treatments in orthopedic surgery such as joint replacement, tumor surgery, and spinal operations are presented and assessed. Present applications for carbon fiber reinforced plastics are seen in the field of spinal surgery, both as cages for interbody fusion and vertebral body replacement.

Replacement of glycoprotein B gene in the Herpes simplex virus type 1 strain ANGpath DNA that originating from non-pathogenic strain KOS reduces the pathogenicity of recombinant virus

International Nuclear Information System (INIS)

Kostal, M.; Bacik, I.; Rajcani, J.; Kaerner, H.C.

1994-01-01

Herpes simplex virus type-1 (HSV-1) strain ANGpath and its recombinants, in which the 8.1 kbp BamHI G restriction fragment (0.345-0.399) containing the glycoprotein B (gB path ) gene (UL27) or its sub-fragments-coding either for cytoplasmic or surface domain of gB-had been replaced with the corresponding fragments from non-pathogenic KOS virus DNA (gB KOS ), were tested for their pathogenicity for DBA/2 mice and rabbits. The recombinant ANGpath/B6 KOS prepared by transferring the 2.7 kbp SstI-SstI sub-fragment (0.351-0.368) of the BamHI G KOS fragment still had the original sequence of ANGpath DNA coding for the syn 3 marker in the cytoplasmic domain of gB and was pathogenic for mice as well as for rabbits. Virological and immuno-histological studies in DBA/2 mice infected with the latter pathogenic recombinant and with ANGpath showed the presence of infectious virus and viral antigen at inoculation site (epidermis, subcutaneous connective tissue and striated muscle in the area of right lip), in homo-lateral trigeminal nerve and ganglion, brain stem, midbrain, thalamic and hypothalamic nuclei. In contrast, non-pathogenic recombinants ANGpath/syn + B6 KOS (prepared by transferring the whole BamHI G KOS fragment) and ANGpath/syn +KOS (prepared by transferring the 0.8 kbp BamHI-SstI sub-fragment of the BamHI G KOS fragment) showed limited hematogenous and neural spread, but no evidence of replication in CNS; thus, their behaviour resembled that of the wild type strain KOS. The recombinant ANGpath/syn +KOS , which was not pathogenic for mice, still remained pathogenic for rabbits, a phenomenon indicating the presence of an additional locus in the gB molecule participating on virulence. Sequencing the 1478 bp SstI-SstI sub-fragment of the BamHI G path fragment (nt 53,348 - 54,826 of UL segment) showed the presence of at least 3 mutations as compared to the KOS sequence, from which the change of cytosine at nt 54,2251 altered the codon for arginine to that histidine

Short Term Evaluation of an Anatomically Shaped Polycarbonate Urethane Total Meniscus Replacement in a Goat Model.

Directory of Open Access Journals (Sweden)

A C T Vrancken

Full Text Available Since the treatment options for symptomatic total meniscectomy patients are still limited, an anatomically shaped, polycarbonate urethane (PCU, total meniscus replacement was developed. This study evaluates the in vivo performance of the implant in a goat model, with a specific focus on the implant location in the joint, geometrical integrity of the implant and the effect of the implant on synovial membrane and articular cartilage histopathological condition.The right medial meniscus of seven Saanen goats was replaced by the implant. Sham surgery (transection of the MCL, arthrotomy and MCL suturing was performed in six animals. The contralateral knee joints of both groups served as control groups. After three months follow-up the following aspects of implant performance were evaluated: implant position, implant deformation and the histopathological condition of the synovium and cartilage.Implant geometry was well maintained during the three month implantation period. No signs of PCU wear were found and the implant did not induce an inflammatory response in the knee joint. In all animals, implant fixation was compromised due to suture breakage, wear or elongation, likely causing the increase in extrusion observed in the implant group. Both the femoral cartilage and tibial cartilage in direct contact with the implant showed increased damage compared to the sham and sham-control groups.This study demonstrates that the novel, anatomically shaped PCU total meniscal replacement is biocompatible and resistant to three months of physiological loading. Failure of the fixation sutures may have increased implant mobility, which probably induced implant extrusion and potentially stimulated cartilage degeneration. Evidently, redesigning the fixation method is necessary. Future animal studies should evaluate the improved fixation method and compare implant performance to current treatment standards, such as allografts.

Microblota around root-form endosseous implants : A review of the literature

NARCIS (Netherlands)

Heydenrijk, K; Meijer, HJA; van der Reijden, WA; Raghoebar, GM; Vissink, A; Stegenga, B

2002-01-01

Although high success rates for root-form endosseous implants have been reported, failures occasionally occur, and these implants must be removed. At least 10% of the failures have been suggested to be the result of peri-implantitis. There is some evidence that periodontal pathogens, mainly those

Patellofemoral Joint Replacement and Nickel Allergy: An Unusual Presentation

Directory of Open Access Journals (Sweden)

Farhan Syed

2015-01-01

Full Text Available Metal allergy is an unusual complication of joint replacement that may cause aseptic loosening and necessitate joint revision surgery. We present the case of nickel allergy causing aseptic loosening following patellofemoral joint replacement (PFJR in a 54-year-old male. Joint revision surgery to a nickel-free total knee replacement was performed with good results. Our literature review shows that there is no evidence to guide the management of metal allergy in PFJR. The evidence from studies of total knee replacement is limited to retrospective case series and case reports and gives contradictory recommendations. The optimal management strategy for metal allergy in PFJR is not clear. We recommend allergy testing in patients with history of metal allergy and use of an allergen-free implant in those with positive tests. As there is no gold standard test to establish metal allergy, the choice of test should be guided by availability and recommendation from the local unit of dermatology and allergy testing. We recommend investigation for metal allergy in patients with implant loosening where other causes have been excluded.

Tackling the Issue of High Postoperative Pacemaker Implantation Rates in Sutureless Aortic Valve Replacement: Should Balloon Inflation be Removed from the Implantation Method of the Perceval Prosthesis?

Science.gov (United States)

Charles Blouin, Mathieu; Bouhout, Ismail; Demers, Philippe; Carrier, Michel; Perrault, Louis; Lamarche, Yoan; El-Hamamsy, Ismail; Bouchard, Denis

2017-05-01

Sutureless aortic valve replacement (AVR) is an emerging alternative to standard AVR in elderly and high-risk patients. This procedure is associated with a high rate of postoperative permanent pacemaker implantation (PPI). The study aim was to assess the impact on the rate of PPI of implanting the Perceval prosthesis without using balloon inflation. A total of 159 patients who underwent sutureless AVR using the Perceval prosthesis was included. Balloon inflation was used in 132 patients (Balloon group) and not used in the remaining 27 (No-Balloon group). Clinical, echocardiographic and electrocardiographic outcomes were assessed. There was no significant difference in PPI rate between the two groups (26% for Balloon group versus 22% in No-Balloon group; p = 0.700). Balloon inflation had no significant impact on the incidence of paravalvular leaks (p = 0.839), or on the need to return to cardiopulmonary bypass (CPB) intraoperatively due to paravalvular leak or unsatisfactory deployment (p >0.999). Mean and peak transaortic pressure gradients were similar between the two groups (p = 0.417 and p = 0.522, respectively). Cross-clamp and CPB times were shorter in the No-Balloon group (49.6 ± 15.9 min versus 61.1 ± 25.6 min and 64.1 ± 26.3 min versus 79.6 ± 35.4 min, respectively; p = 0.027 and p = 0.012, respectively). The two groups had similar postoperative PPI rates. Implanting the Perceval prosthesis without balloon inflation is safe and had no impact on paravalvular leaks, intraoperative complications or hemodynamic results. Reductions in aortic cross-clamp time and CPB time were observed when the balloon was not used.

Evaluation of design parameters of eight dental implant designs: A ...

African Journals Online (AJOL)

Aim: Implants could be considered predictable tools for replacing missing teeth or teeth that are irrational to treat. Implant macrodesign includes thread, body shape and thread design. Implant threads should be designed to maximize the delivery of optimal favorable stresses. The aim of this finite element model study was to ...

Mandibular implant-supported overdentures: attachment systems, and number and locations of implants--Part I.

Science.gov (United States)

Warreth, Abdulhadi; Alkadhimi, Aslam Fadel; Sultan, Ahmed; Byrne, Caroline; Woods, Edel

2015-01-01

The use of dental implants in replacing missing teeth is an integral part of restorative dental treatment. Use of conventional complete dentures is associated with several problems such as lack of denture stability, support and retention. However, when mandibular complete dentures were used with two or more implants, an improvement in the patients' psychological and social well-being could be seen. There is general consensus that removable implant-supported overdentures (RISOs) with two implants should be considered as the first-choice standard of care for an edentulous mandible. This treatment option necessitates the use of attachment systems that connect the complete denture to the implant. Nevertheless, each attachment system has its inherent advantages and disadvantages, which should be considered when choosing a system. The first part of this article provides an overview on options available to restore the mandibular edentulous arch with dental implants. Different types of attachment systems, their features and drawbacks are also reviewed.

Finite element study of a lumbar intervertebral disc nucleus replacement device

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Jessica S Coogan

2016-12-01

Full Text Available Nucleus replacement technologies are a minimally invasive alternative to spinal fusion and total disc replacement that have the potential to reduce pain and restore motion for patients with degenerative disc disease. Finite element modeling can be used to determine the biomechanics associated with nucleus replacement technologies. The current study focuses on a new nucleus replacement device designed as a conforming silicone implant with an internal void. A validated finite element model of the human lumbar L3-L4 motion segment was developed and used to investigate the influence of the nucleus replacement device on spine biomechanics. In addition, the effect of device design changes on biomechanics was determined. A 3D, L3-L4 finite element model was constructed from medical imaging data. Models were created with the normal intact nucleus, the nucleus replacement device, and a solid silicone implant. Probabilistic analysis was performed on the normal model to provide quantitative validation metrics. Sensitivity analysis was performed on the silicone Shore A durometer of the device. Models were loaded under axial compression followed by flexion/extension, lateral bending, or axial rotation. Compressive displacement, endplate stresses, reaction moment, and annulus stresses were determined and compared between the different models. The novel nucleus replacement device resulted in similar compressive displacement, endplate stress, and annulus stress and slightly higher reaction moment compared with the normal nucleus. The solid implant resulted in decreased displacement, increased endplate stress, decreased annulus stress, and decreased reaction moment compared with the novel device. With increasing silicone durometer, compressive displacement decreased, endplate stress increased, reaction moment increased, and annulus stress decreased. Finite element analysis was used to show that the novel nucleus replacement device results in similar biomechanics

Intraindividual variation in core microbiota in peri-implantitis and periodontitis

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Maruyama, Noriko; Maruyama, Fumito; Takeuchi, Yasuo; Aikawa, Chihiro; Izumi, Yuichi; Nakagawa, Ichiro

2014-01-01

The oral microbiota change dramatically with each part of the oral cavity, even within the same mouth. Nevertheless, the microbiota associated with peri-implantitis and periodontitis have been considered the same. To improve our knowledge of the different communities of complex oral microbiota, we compared the microbial features between peri-implantitis and periodontitis in 20 patients with both diseases. Although the clinical symptoms of peri-implantitis were similar to those of periodontitis, the core microbiota of the diseases differed. Correlation analysis revealed the specific microbial co-occurrence patterns and found some of the species were associated with the clinical parameters in a disease-specific manner. The proportion of Prevotella nigrescens was significantly higher in peri-implantitis than in periodontitis, while the proportions of Peptostreptococcaceae sp. and Desulfomicrobium orale were significantly higher in periodontitis than in peri-implantitis. The severity of the peri-implantitis was also species-associated, including with an uncultured Treponema sp. that correlated to 4 clinical parameters. These results indicate that peri-implantitis and periodontitis are both polymicrobial infections with different causative pathogens. Our study provides a framework for the ecologically different bacterial communities between peri-implantitis and periodontitis, and it will be useful for further studies to understand the complex microbiota and pathogenic mechanisms of oral polymicrobial diseases. PMID:25308100

R&D on dental implants breakage

Science.gov (United States)

Croitoru, Sorin Mihai; Popovici, Ion Alexandru

2017-09-01

Most used dental implants for human dental prostheses are of two steps type: first step means implantation and, after several months healing and osseointegration, second step is prosthesis fixture. For sure, dental implants and prostheses are meant to last for a lifetime. Still, there are unfortunate cases when dental implants break. This paper studies two steps dental implants breakage and proposes a set of instruments for replacement and restoration of the broken implant. First part of the paper sets the input data of the study: structure of the studied two steps dental implants based on two Romanian patents and values of the loading forces found in practice and specialty papers. In the second part of the paper, using DEFORM 2D™ FEM simulation software, worst case scenarios of loading dental implants are studied in order to determine which zones and components of the dental implant set are affected (broken). Last part of the paper is dedicated to design and presentation of a set for extracting and cutting tools used to restore the broken implant set.

Orthodontic Anchorage Implants: State-of-the-art

DEFF Research Database (Denmark)

Melsen, Birte

2007-01-01

The limits of an orthodontic treatment are often set by the lack of suitable anchorage. The mini-implant is used where conventional anchorage cannot be applied and not as a replacement for conventional anchorage. In patients with lack of teeth and reduced periodontium, skeletal anchorage allows...... will improve the reconstruction possibilities. The mini-implant has widened the orthodontic possibilities....

Aortic Root Enlargement or Sutureless Valve Implantation?

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Nikolaos G. Baikoussis

2016-11-01

Full Text Available Aortic valve replacement (AVR in patients with a small aortic annulus is a challenging issue. The importance of prosthesis–patient mismatch (PPM post aortic valve replacement (AVR is controversial but has to be avoided. Many studies support the fact that PPM has a negative impact on short and long term survival. In order to avoid PPM, aortic root enlargement may be performed. Alternatively and keeping in mind that often some comorbidities are present in old patients with small aortic root, the Perceval S suturelles valve implantation could be a perfect solution. The Perceval sutureless bioprosthesis provides reasonable hemodynamic performance avoiding the PPM and providing the maximum of aortic orifice area. We would like to see in the near future the role of the aortic root enlargement techniques in the era of surgical implantation of the sutureless valve (SAVR and the transcatheter valve implantation (TAVI.

Interventions for replacing missing teeth: antibiotics at dental implant placement to prevent complications.

Science.gov (United States)

Esposito, Marco; Grusovin, Maria Gabriella; Worthington, Helen V

2013-07-31

Some dental implant failures may be due to bacterial contamination at implant insertion. Infections around biomaterials are difficult to treat, and almost all infected implants have to be removed. In general, antibiotic prophylaxis in surgery is only indicated for patients at risk of infectious endocarditis; with reduced host-response; when surgery is performed in infected sites; in cases of extensive and prolonged surgical interventions; and when large foreign materials are implanted. A variety of prophylactic systemic antibiotic regimens have been suggested to minimise infections after dental implant placement. More recent protocols recommended short-term prophylaxis, if antibiotics have to be used. Adverse events may occur with the administration of antibiotics, and can range from diarrhoea to life-threatening allergic reactions. Another major concern associated with the widespread use of antibiotics is the selection of antibiotic-resistant bacteria. The use of prophylactic antibiotics in implant dentistry is controversial. To assess the beneficial or harmful effects of systemic prophylactic antibiotics at dental implant placement versus no antibiotic or placebo administration and, if antibiotics are beneficial, to determine which type, dosage and duration is the most effective. We searched the Cochrane Oral Health Group's Trials Register (to 17 June 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 5), MEDLINE via OVID (1946 to 17 June 2013) and EMBASE via OVID (1980 to 17 June 2013). There were no language or date restrictions placed on the searches of the electronic databases. Randomised controlled clinical trials (RCTs) with a follow-up of at least three months, that compared the administration of various prophylactic antibiotic regimens versus no antibiotics to people undergoing dental implant placement. Outcome measures included prosthesis failures, implant failures, postoperative infections and adverse

The effect of shape, length and diameter of implants on primary stability based on resonance frequency analysis

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Hamidreza Barikani

2014-01-01

Full Text Available Background: The aim of this in vitro study was to evaluate the effect of shape, diameter and length of implants on their primary stability based on resonance frequency analysis. Materials and Methods: Replace select tapered and Branemark MK III implants were selected. Each of these two selected groups was divided into nine subgroups based on the implant length (IL (short, medium and long and the implant diameter (ID (narrow platform [NP], regular platform [RP] and wide platform [WP]. Five implants were assigned to each of the nine subgroups. Implants were placed in artificial bone blocks with bone quality similar to D3 bone. Immediately after the implant placement, its primary stability was measured using Osstell Mentor equipment. T-test and Tukey′s honest significant difference Post hoc were performed for data analysis. Statistical significance was defined at P < 0.05. Results: Replace select system showed significantly higher primary stability compared to the Branemark system, when using the short implants for all three diameters (P ≤ 0.004. However, in medium length implants there were no significant differences between the two implant systems (P ≥ 0.31. In long implants, only when the NP and RP implants were used, the Replace Select system showed significantly higher primary stability compared to the Branemark system (P = 0.000. In the replace select system, long implants had a significantly higher primary stability compared to medium and short length implants (P ≤ 0.003. In the NP and RP Branemark implants, short implants showed significantly lower primary stability compared to medium and long implants (P ≤ 0.002. However, in WP Branemark implants, primary stability increased significantly with increasing the IL from short to medium and from medium to long (P = 0.000. There were also significant differences between NP and the two other wider implants in both systems (P = 0.000. Conclusion: The use of tapered implants is

A rare case report of peri-implant bone necrosis: Mapping the distance of initial peri-implant complication toward a path of success

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S K Salaria

2011-01-01

Full Text Available In the past decade, science of implant placement has greatly advanced and at the same time much success has been experienced with the endosseous implant. Despite the long-term predictability of the implants, however, biological, technical and esthetic complications do occur. The use of osseointegrated implants as a foundation for prosthetic replacement of missing teeth has been highly predictable, but still at present, there is no consensus of how to best manage the complications occurring after implant placement. In this report, we discuss post-insertion complication of bone necrosis and its successful management.

The predictive value of microbiological findings on teeth, internal and external implant portions in clinical decision making.

Science.gov (United States)

Canullo, Luigi; Radovanović, Sandro; Delibasic, Boris; Blaya, Juan Antonio; Penarrocha, David; Rakic, Mia

2017-05-01

The primary aim of this study was to evaluate 23 pathogens associated with peri-implantitis at inner part of implant connections, in peri-implant and periodontal pockets between patients suffering peri-implantitis and participants with healthy peri-implant tissues; the secondary aim was to estimate the predictive value of microbiological profile in patients wearing dental implants using data mining methods. Fifty participants included in the present case─control study were scheduled for collection of plaque samples from the peri-implant pockets, internal connection, and periodontal pocket. Real-time polymerase chain reaction was performed to quantify 23 pathogens. Three predictive models were developed using C4.5 decision trees to estimate the predictive value of microbiological profile between three experimental sites. The final sample included 47 patients (22 healthy controls and 25 diseased cases), 90 implants (43 with healthy peri-implant tissues and 47 affected by peri-implantitis). Total and mean pathogen counts at inner portions of the implant connection, in peri-implant and periodontal pockets were generally increased in peri-implantitis patients when compared to healthy controls. The inner portion of the implant connection, the periodontal pocket and peri-implant pocket, respectively, presented a predictive value of microbiologic profile of 82.78%, 94.31%, and 97.5% of accuracy. This study showed that microbiological profile at all three experimental sites is differently characterized between patients suffering peri-implantitis and healthy controls. Data mining analysis identified Parvimonas micra as a highly accurate predictor of peri-implantitis when present in peri-implant pocket while this method generally seems to be promising for diagnosis of such complex infections. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Inherent challenges of immediate implant placement in the aesthetic ...

African Journals Online (AJOL)

Replacement of missing teeth with implant borne prostheses has become generally become acceptable in the field of dentistry. The traditional “Branemark protocol” has advocated for a period of healing after extraction before placement of implants. This presents an aesthetic challenge and the ensuing bone resorption also ...

Importance of cochlear health for implant function.

Science.gov (United States)

Pfingst, Bryan E; Zhou, Ning; Colesa, Deborah J; Watts, Melissa M; Strahl, Stefan B; Garadat, Soha N; Schvartz-Leyzac, Kara C; Budenz, Cameron L; Raphael, Yehoash; Zwolan, Teresa A

2015-04-01

Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy cochlea and improve performance obtained by cochlear implant recipients or eventually replace the need for a cochlear implant. This article is part of a Special Issue entitled . Copyright © 2014 Elsevier B.V. All rights reserved.

Immediate provisional restoration of an implant placed in a fresh primary maxillary canine extraction socket: a case report.

Science.gov (United States)

Turkyilmaz, Ilser; Shapiro, Vladimir

2011-01-01

This study describes a clinical case in which a primary maxillary canine with both mobility and root resorption was replaced with an immediately restored dental implant placed into the fresh extraction socket. The implant achieved high primary stability, as determined by resonance frequency analysis, and it was immediately restored with a provisional acrylic resin crown with no centric occlusion. An all-ceramic permanent crown replaced the provisonal crown four months after implant surgery. The implant was stable and no periapical radiolucencies, bleeding on probing, or pathologic probing depth were recorded after one year. The peri-implant soft tissue level appeared stable, and the interdental papillae were preserved, contributing to an optimum final esthetic result. This case supports the use of single implants for the replacement of extracted primary teeth, especially in areas where esthetics is a high priority. The immediate provisional crown maintained soft tissue contours and papillary height.

[Custom-designed 3D tibial augmentation for knee replacement].

Science.gov (United States)

Jirman, R; Vavrík, P; Horák, Z

2009-02-01

Reconstruction with the use of custom-made implants aims at optimal replacement of lost or damaged bone structures and restoration of their funkction. In this study the development and construction of a custom-made implant and the operative technique used for the treatment of an extensive tibial defect are described. The patient was a 65-year-old man treated for over 20 years for psoriatic arthritis and severe instability of the right knee, particularly in the frontal plane, with a worsening varus deformity. The radiogram showed an extensive destruction of the medial tibial condyle that also deeply involved the lateral condyle. The extent of defect made it impossible to use any commercial tibial augmentation. The geometry of the custom-designed implant for the medial tibial condyle was constructed on the basis of a 3D defect model and the shape of the medial tibial condyle of the collateral knee seen on CT scans. After its correct shape was verified on a plastic model, its coordinates were set in the software of a machine tool, and a titanium augmentation otherwise compatible with a standard knee replacement was produced.The use of such a custom implant to complete standard total knee arthroplasty has so far been demanding in terms of organisation and manufacture. Its production in the future could be facilitated by substituting titanium for plastic material such as poly-ether-ether-ketone (PEEK). Key words: custom-made implant, tibial augmentation, knee prosthesis.

The effects of bone marrow aspirate, bone graft, and collagen composites on fixation of titanium implants

DEFF Research Database (Denmark)

Babiker, Hassan; Ding, Ming; Sandri, Monica

2012-01-01

Replacement of extensive local bone loss especially in revision joint arthroplasty and spine fusion is a significant clinical challenge. Allograft and autograft have been considered as gold standards for bone replacement. However, there are several disadvantages such as donor site pain, bacterial...... contamination, and non union as well as the potential risk of disease transmission. Hydroxyapatite and collagen composites (HA/Collagen) have the potential in mimicking and replacing skeletal bones. This study attempted to determine the effects of newly developed HA/Collagen-composites with and without bone...... marrow aspirate (BMA) on enhancement of bone implant fixation. Method: Titanium alloy implants were inserted into bilateral femoral condyles of eight skeletally mature sheep, four implants per sheep. The implant had a circumferential gap of 2 mm. The gap was filled with: HA/Collagen; HA...

Aortic valve replacement and prosthesis-patient mismatch in the era of trans-catheter aortic valve implantation.

Science.gov (United States)

Morita, Shigeki

2016-08-01

The treatment strategy for aortic stenosis (AS) has been changing due to newly developed valvular prostheses and trans-catheter aortic valve implantation (TAVI). To determine the role of new modalities for AS with a small aortic root, papers using the concept of prosthesis-patient mismatch (PPM) were reviewed. First, to determine the cut-off value of the indexed effective orifice area (IEOA) for defining PPM, the studies of surgical aortic valve replacement (SAVR) with a follow-up longer than 5 years and a patient number larger than 500 were reviewed. Second, the papers comparing TAVI and SAVR were reviewed. Furthermore, the prevalence of PPM was reviewed, with the addition of papers on aortic root enlargement, sutureless AVR, and aortic valve reconstruction with autologous pericardium. The results of the long-term survival after aortic valve replacement (AVR) have indicated that an IEOA less than 0.65 cm(2)/m(2) should be avoided in all cases, whereas the indications for patients with an IEOA between 065 and 0.85 cm(2)/m(2) should be determined by considering multiple factors. A large body size and younger age have a significantly negative influence on the long-term survival. In Asian population, the prevalence of PPM was low, despite the fact that the size of the aortic annulus was small. The IEOA after TAVI was larger than after surgical AVR in population-matched studies. To evaluate the role of TAVI and other modalities for a small aortic root, studies with a longer follow-up and larger volume are thus warranted.

Wear mechanisms in ceramic hip implants.

Science.gov (United States)

Slonaker, Matthew; Goswami, Tarun

2004-01-01

The wear in hip implants is one of the main causes for premature hip replacements. The wear affects the potential life of the prosthesis and subsequent removals of in vivo implants. Therefore, the objective of this article is to review various joints that show lower wear rates and consequently higher life. Ceramics are used in hip implants and have been found to produce lower wear rates. This article discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations.

Influence of bacterial colonization of the healing screws on peri-implant tissue

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Simonetta D'Ercole

2013-06-01

Conclusion: The healing screws left in situ for a period of 90 days caused a peri-implant inflammation and the presence of periodontal pathogenic bacteria in the peri-implant sulcus, due to the plaque accumulation on screw surfaces.

Intervention for replacing missing teeth: Different types of implants - evidence summary of updated Cochrane review

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Balendra Pratap Singh

2015-01-01

Full Text Available Around 1300 different types of dental implants are available worldwide and the implant manufacturers are resorting to aggressive marketing strategies; claiming their implants to provide a superior outcome. The clinician is left with a constant dilemma on which implant to choose for better clinical outcome and welfare of the patient. Moreover, in India, economical consideration is a concern too. The dentist has to select an implant that provides a good result and is economical. Cochrane systematic reviews provide the gold standard evidence for intervention, diagnosis, etc., and follow a strict quality control. A Cochrane systematic review was done to shed light on whether the different implant surface modifications, shapes or materials significantly influence clinical outcomes. All randomized controlled trials (RCTs till January 17, 2014 were searched and out of the 81 trials, only 27 met the inclusion criteria. This evidence summary from the review concludes that based on the available literature; there is no evidence of any one type of implant being superior to another. There is weak evidence showing roughened dental implants are more prone to bone loss due to periimplantitis. This review indicated that there is a need for well-designed RCTs, with long-term follow-up and low bias. Moreover, none of the included studies was from India, which also points out the need for improving the quality of RCTs conducted in India.

The role of hinges in primary total knee replacement.

Science.gov (United States)

Gehrke, T; Kendoff, D; Haasper, C

2014-11-01

The use of hinged implants in primary total knee replacement (TKR) should be restricted to selected indications and mainly for elderly patients. Potential indications for a rotating hinge or pure hinge implant in primary TKR include: collateral ligament insufficiency, severe varus or valgus deformity (>20°) with necessary relevant soft-tissue release, relevant bone loss including insertions of collateral ligaments, gross flexion-extension gap imbalance, ankylosis, or hyperlaxity. Although data reported in the literature are inconsistent, clinical results depend on implant design, proper technical use, and adequate indications. We present our experience with a specific implant type that we have used for over 30 years and which has given our elderly patients good mid-term results. Because revision of implants with long cemented stems can be very challenging, an effort should be made in the future to use shorter stems in modular versions of hinged implants. ©2014 The British Editorial Society of Bone & Joint Surgery.

Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

DEFF Research Database (Denmark)

Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas

2010-01-01

Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen...

A prospective, split-mouth study comparing tilted implants with angulated connection versus conventional implants with angulated abutment.

Science.gov (United States)

Van Weehaeghe, Manú; De Bruyn, Hugo; Vandeweghe, Stefan

2017-12-01

An angulation of the implant connection could overcome the problems related to angulated abutments. This study compares conventional implants with angulated abutment to tilted implants with an angulated connection. Twenty patients were treated in the edentulous mandible. In the posterior jaw locations, one conventional tilted implant with angulated abutment and one angulated implant without abutment were placed. In the anterior jaw, two conventional implants were placed, one with and one without abutment. Implants were immediately loaded and 3 months later, the final bridge (PFM or monolithic zirconia) was placed. After a follow-up of 48 months, 17 patients were available for clinical examination. The mean overall marginal bone loss (MBL) was 1.26 mm. No significant differences in implant survival, MBL, periodontal indices, patients' satisfaction, or complications was found between implants restored on abutment or implant level, between the posteriorly located angulated implant nor angulated abutment, and between both anterior implants with or without abutment. The posterior implants demonstrated less MBL compared to the anterior implants (P abutment were replaced and four loose bridge screws connected to the angulated abutments had to be tightened. Patients were overall satisfied (4.74/5). An implant with angulated connection may results in a stronger connection but does not affect the marginal bone loss. No difference in MBL was seen between implants restored on abutment or implant level. Zirconia seems to reduce the amount of plaque. © 2017 Wiley Periodicals, Inc.

Optimal implantation depth and adherence to guidelines on permanent pacing to improve the results of transcatheter aortic valve replacement with the medtronic corevalve system: The CoreValve prospective, international, post-market ADVANCE-II study

NARCIS (Netherlands)

A.S. Petronio (Anna); J.-M. Sinning (Jan-Malte); N.M. van Mieghem (Nicolas); G. Zucchelli (Giulio); G. Nickenig (Georg); R. Bekeredjian (Raffi); J. Bosmans (Johan); F. Bedogni (Francesco); M. Branny (Marian); K. Stangl (Karl); J. Kovac (Jan); M. Schiltgen (Molly); S. Kraus (Stacia); P.P.T. de Jaegere (Peter)

2015-01-01

textabstractObjectives The aim of the CoreValve prospective, international, post-market ADVANCE-II study was to define the rates of conduction disturbances and permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement with the Medtronic CoreValve System (Minneapolis,

Two different techniques of manufacturing TMJ replacements - A technical report.

Science.gov (United States)

Kozakiewicz, Marcin; Wach, Tomasz; Szymor, Piotr; Zieliński, Rafał

2017-09-01

Presently, during the surgical treatment of the patients in maxillofacial surgery, one can use various medical implants. Moreover custom made implants are being used. Replacements may be fitted to the structure and shape of the human skull owing to CAD/CAM (custom aided design/manufacture) called customized implants. This study was aimed to report for the first time clinical material from which custom implants, using two different techniques, were manufactured to reconstruct the temporomandibular joint (TMJ). In this study, eleven patients with an average age of 54 years were included. All of the patients underwent TMJ reconstruction using direct metal laser sintering (DMLS) or computer numerical control milling (CNC) techniques for implant manufacture. Four of the eleven patients had a malignancy diagnosis, and seven had a benign diagnosis. Patients complained of hypomobility of the TMJ, facial asymmetry, pain and swelling of the preauricular region. Treatment included 7 CNC milled implants and 4 implants in DMLS. More metallic implant parts with a rough surface were associated with the DMLS technique. Post operational, uneventful healing was observed in all clinical cases during an average of 26.8 months of follow-up. Three months post-operation, facial nerve palsy, swallowing disturbances and pain were not observed. Infections, allergic reactions to materials and re-ankylosis were also not observed. Replacements received correct forms and functions owing to the CAM techniques. Post-operational maximal interincisal opening improved (p < 0.01) and was not significantly related to preoperational opening, age, sex, diagnosis or adjuvant radiotherapy. Considering both methods, the feature that differentiates the manufacture technique is the more subtractive surface finishing required for the DMLS implant than the CNC implant. Both techniques resulted the same clinical outcomes and can be used successfully in patients with neoplastic lesions and other TMJ disorders

Penile Prosthesis First and Replacement Surgeries: Analysis of Patient and Partner Satisfaction.

Science.gov (United States)

Lledó-García, Enrique; Jara-Rascón, José; Moncada Iribarren, Ignacio; Piñero-Sánchez, Javier; Aragón-Chamizo, Juan; Hernández-Fernández, Carlos

2015-07-01

Among the many treatments for erectile dysfunction, implantation of a penile prosthesis has been associated with high patient satisfaction rates. Prosthesis replacement has become an accepted procedure in the event of device malfunction or complications, but to our knowledge, there are no data regarding the impact of implant replacement on patients and partner satisfaction. The aim of our study was to assess and to compare the level of satisfaction, with a first or second penile prosthesis implantation (PPI), in men with refractory erectile dysfunction and their partners. A survey study based on a five-item questionnaire was carried out at our center between January 1999 and January 2012. The main outcome measure used was the level of patient and partner satisfaction with sexual intercourse after PPI. Of the 190 eligible patients, 149 (78%) completed the survey (110 underwent a first implant and 39 a reimplant). Seventy-nine percent of first-time implanted patients and 80% of the reimplanted patients (P > 0.05; not significant [ns]) reported satisfactory sexual intercourse (very or moderately satisfied), while 74% and 80% of their partners reported satisfactory intercourses, respectively (P > 0.05; ns). Overall, 73.7% of first implants and 70% of second implants reported that they would undergo the procedure again if the PPI failed (P > 0.05; ns). With regards to cosmetic aspects, 13% of the first implants' and 15% of second implants' partners reported either penile shortness or soft glans as the main causes of their dissatisfaction. Only 2.4% of first implants and 1% of reimplanted patients expressed difficulty in manipulating the device. PPI is successful in returning the ability for satisfactory sexual intercourse to both first implant and reimplanted patients and their respective partners. © 2015 International Society for Sexual Medicine.

Anesthesia management for MitraClip device implantation

Directory of Open Access Journals (Sweden)

Harikrishnan Kothandan

2014-01-01

Full Text Available Aims and Objectives: Percutaneous MitraClip implantation has been demonstrated as an alternative procedure in high-risk patients with symptomatic severe mitral regurgitation (MR who are not suitable (or denied mitral valve repair/replacement due to excessive co morbidity. The MitraClip implantation was performed under general anesthesia and with 3-dimensional transesophageal echocardiography (TEE and fluoroscopic guidance. Materials and Methods: Peri-operative patient data were extracted from the electronic and paper medical records of 21 patients who underwent MitraClip implantations. Results: Four MitraClip implantation were performed in the catheterization laboratory; remaining 17 were performed in the hybrid operating theatre. In 2 patients, procedure was aborted, in one due to migration of the Chiari network into the left atrium and in second one, the leaflets and chords of the mitral valve torn during clipping resulting in consideration for open surgery. In the remaining 19 patients, MitraClip was implanted and the patients showed acute reduction of severe MR to mild-moderate MR. All the patients had invasive blood pressure monitoring and the initial six patients had central venous catheterization prior to the procedure. Intravenous heparin was administered after the guiding catheter was introduced through the inter-atrial septum and activated clotting time was maintained beyond 250 s throughout the procedure. Protamine was administered at the end of the procedure. All the patients were monitored in the intensive care unit after the procedure. Conclusions: Percutaneous MitraClip implantation is a feasible alternative in high-risk patients with symptomatic severe MR. Anesthesia management requirements are similar to open surgical mitral valve repair or replacement. TEE plays a vital role during the MitraClip implantation.

Poly Implants Prosthèse Breast Implants: A Case Series and Review of the Literature.

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Klein, Doron; Hadad, Eran; Wiser, Itay; Wolf, Omer; Itzhaki Shapira, Ortal; Fucks, Shir; Heller, Lior

2018-01-01

Silicone breast implants from the French manufacturer Poly Implants Prosthèse (PIP) were recalled from the European market after the French regulator has revealed the implants contain non-medical-grade silicone filler. In December 2011, following a large increase in reported rupture rate and a possible cancer risk, the French Ministry of Health recommended consideration of the PIP explantation, regardless of their condition. In 2012, the Israel Ministry of Health recommended to replace the implants only upon suspected implant rupture. The aims of this study were to characterize breast-augmented Israeli patients with PIP implants, compare their outcomes with those of breast-augmented patients with different implant types, and review the current PIP literature. Breast-augmented patients who underwent an elective breast implant exchange in Israel between January 2011 and January 2017 were included in the study. Data were collected from electronic and physical medical files. There were 73 breast-augmented female patients with 146 PIP breast implants included in this study. Average implant age was 6.7 ± 2.79 years. Mean implant size was 342.8 ± 52.9 mL. Fourteen women (19 implants [16%]) had a high-grade capsular contracture (Baker grade 3-4). During exchange, 28 implants were found to be ruptured (19.2%). Less than 10 years following breast augmentation, PIP implants demonstrated higher rupture rate compared with other implants. Our data are comparable to overall available rupture rate. Among patients with definitive rupture diagnosis, an elective implant removal should be recommended. In cases of undamaged implants, plastic surgeons should also seriously consider PIP implant explantation. When the patient does not desire to remove the implant, an annual physical examination and breast ultrasound are recommended, beginning a year after augmentation.

Awareness of dental implants among dental patients in Nigeria ...

African Journals Online (AJOL)

The aim of this study was to determine the level of awareness of dental implant in Nigerian patients and their willingness to choose dental implant as a tooth replacement option. A survey was conducted among patients presenting for dental treatment in 3 teaching hospitals and private dental clinics in 3 urban cities of ...

Delayed Presentation of a Giant Ascending Aortic Aneurysm following Aortic Valve Replacement

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Tugrul Göncü

2009-01-01

Full Text Available Giant ascending aortic aneurysm formation following aortic valve replacement is rare. A 28-year-old man who underwent aortic valve replacement with a prosthetic valve for aortic regurgitation secondary to congenital bicuspid aortic valve about 10 years ago was diagnosed with a giant ascending aortic aneurysm about 16 cm in diameter in follow-up. The aneurysm was resected leaving the functional old mechanical prosthesis in place and implanted a 34-mm Hemashield woven graft, associated with the left and right coronary artery button implantation. Histological findings of the aortic aneurysm wall showed cystic medial necrosis. The postoperative course was uneventful and postoperative examination demonstrated good surgical results.

Influence of conformity on the wear of total knee replacement: An experimental study.

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Brockett, Claire L; Carbone, Silvia; Fisher, John; Jennings, Louise M

2018-02-01

Wear of total knee replacement continues to be a significant factor influencing the clinical longevity of implants. Historically, failure due to delamination and fatigue directed design towards more conforming inserts to reduce contact stress. As new generations of more oxidatively stable polyethylene have been developed, more flexibility in bearing design has been introduced. The aim of this study was to investigate the effect of insert conformity on the wear performance of a fixed bearing total knee replacement through experimental simulation. Two geometries of insert were studied under standard gait conditions. There was a significant reduction in wear with reducing implant conformity. This study has demonstrated that bearing conformity has a significant impact on the wear performance of a fixed bearing total knee replacement, providing opportunities to improve clinical performance through enhanced material and design selection.

MEMS-Based Power Generation Techniques for Implantable Biosensing Applications

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Jonathan Lueke

2011-01-01

Full Text Available Implantable biosensing is attractive for both medical monitoring and diagnostic applications. It is possible to monitor phenomena such as physical loads on joints or implants, vital signs, or osseointegration in vivo and in real time. Microelectromechanical (MEMS-based generation techniques can allow for the autonomous operation of implantable biosensors by generating electrical power to replace or supplement existing battery-based power systems. By supplementing existing battery-based power systems for implantable biosensors, the operational lifetime of the sensor is increased. In addition, the potential for a greater amount of available power allows additional components to be added to the biosensing module, such as computational and wireless and components, improving functionality and performance of the biosensor. Photovoltaic, thermovoltaic, micro fuel cell, electrostatic, electromagnetic, and piezoelectric based generation schemes are evaluated in this paper for applicability for implantable biosensing. MEMS-based generation techniques that harvest ambient energy, such as vibration, are much better suited for implantable biosensing applications than fuel-based approaches, producing up to milliwatts of electrical power. High power density MEMS-based approaches, such as piezoelectric and electromagnetic schemes, allow for supplemental and replacement power schemes for biosensing applications to improve device capabilities and performance. In addition, this may allow for the biosensor to be further miniaturized, reducing the need for relatively large batteries with respect to device size. This would cause the implanted biosensor to be less invasive, increasing the quality of care received by the patient.

MEMS-based power generation techniques for implantable biosensing applications.

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Lueke, Jonathan; Moussa, Walied A

2011-01-01

Implantable biosensing is attractive for both medical monitoring and diagnostic applications. It is possible to monitor phenomena such as physical loads on joints or implants, vital signs, or osseointegration in vivo and in real time. Microelectromechanical (MEMS)-based generation techniques can allow for the autonomous operation of implantable biosensors by generating electrical power to replace or supplement existing battery-based power systems. By supplementing existing battery-based power systems for implantable biosensors, the operational lifetime of the sensor is increased. In addition, the potential for a greater amount of available power allows additional components to be added to the biosensing module, such as computational and wireless and components, improving functionality and performance of the biosensor. Photovoltaic, thermovoltaic, micro fuel cell, electrostatic, electromagnetic, and piezoelectric based generation schemes are evaluated in this paper for applicability for implantable biosensing. MEMS-based generation techniques that harvest ambient energy, such as vibration, are much better suited for implantable biosensing applications than fuel-based approaches, producing up to milliwatts of electrical power. High power density MEMS-based approaches, such as piezoelectric and electromagnetic schemes, allow for supplemental and replacement power schemes for biosensing applications to improve device capabilities and performance. In addition, this may allow for the biosensor to be further miniaturized, reducing the need for relatively large batteries with respect to device size. This would cause the implanted biosensor to be less invasive, increasing the quality of care received by the patient.

The etiological structure, biological properties of causative agents of peri-implant mucositis

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M. O. Faustova

2017-10-01

Full Text Available The purpose was to examine the peri-implant mucositis microflora and sensitivity of dominant pathogens to antibiotics and antiseptics. Materials and methods. The study involved 43 patients with peri-implant mucositis. During the study 162 clinical strains of microorganisms were isolated and identified. Cultivation of clinical isolates was performed by the standard method, final identification was carried out with using bacteriological automatic analyzer Vitec – 2compact bioMérieux (France. Determination of sensitivity to antibiotics of pathogens was carried with disc-diffusion method; the study of sensitivity to antiseptics was carried by means of double serial dilutions method by the standard procedure approved by the Order № 167 of the Ministry of Public Health of Ukraine on “On Approval of Training Guidance “Assessment of the sensitivity of microorganisms to antibiotics”, dated by April, 5, 2007. Results. It is The microflora of peri-implant area of patients with mucositis was revealed to consist of opportunistic species. Representatives of Streptococcus spp. and Staphylococcus spp. were dominating among them, although Kocuria spp., Enterobacter spp. and yeast-like fungi Candida spp. were detected quite common. Investigated clinical strains of microorganisms had different sensitivity to antibiotics. All cultures were sensitive to fluoroquinolones, but very significant number of them showed resistance to penicillins, macrolides and lincosamides. In turn, horosten, dekasan and chlorhexidine had powerful antimicrobial effect on dominant pathogens of periimplant mucositis in patients. Moreover, the effect of decametoxine-based antiseptics on some of them significantly exceeded the activity of chlorhexidine. Conclusions. Microflora from peri-implant area of patients with peri-implant mucositis consists mainly of aerobic and facultative anaerobic microorganisms, belonging to normal oral microflora. Most of pathogens of mucositis obtaine

Glaucoma after corneal replacement.

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Baltaziak, Monika; Chew, Hall F; Podbielski, Dominik W; Ahmed, Iqbal Ike K

Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Current concepts of regenerative biomaterials in implant dentistry

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Annapurna Ahuja

2015-01-01

Full Text Available The primary objective of any implant system is to achieve firm fixation to the bone and this could be influenced by biomechanical as well as biomaterial selection. An array of materials is used in the replacement of missing teeth through implantation. The appropriate selection of biomaterials directly influences the clinical success and longevity of implants. Thus the clinician needs to have adequate knowledge of the various biomaterials and their properties for their judicious selection and application in his/her clinical practice. The recent materials such as bioceramics and composite biomaterials that are under consideration and investigation have a promising future. For optimal performance, implant biomaterials should have suitable mechanical strength, biocompatibility, and structural biostability in the physiological environment. This article reviews the various implant biomaterials and their ease of use in implant dentistry.

Development and application of biomimetic electrospun nanofibers in total joint replacement

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Song, Wei

Failure of osseointegration (direct anchorage of an implant by bone formation at the bone-implant surface) and implant infection (such as that caused by Staphylococcus aureus, S. aureus) are the two main causes of implant failure and loosening. There is a critical need for orthopedic implants that promote rapid osseointegration and prevent bacterial colonization, particularly when placed in bone compromised by disease or physiology of the patients. A better understanding of the key factors that influence cell fate decisions at the bone-implant interface is required. Our study is to develop a class of "bone-like" nanofibers (NFs) that promote osseointegration while preventing bacterial colonization and subsequent infections. This research goal is supported by our preliminary data on the preparation of coaxial electrospun NFs composed of polycaprolactone (PCL) and polyvinyl alcohol (PVA) polymers arranged in a core-sheath shape. The PCL/PVA NFs are biocompatible and biodegradable with appropriate fiber diameter, pore size and mechanical strength, leading to enhanced cell adhesion, proliferation and differentiation of osteoblast precursor cells. The objective is to develop functionalized "bone-like" PCL/PVA NFs matrix embedded with antibiotics (doxycycline (Doxy), bactericidal and anti-osteoclastic) on prosthesis surface. Through a rat tibia implantation model, the Doxy incorporated coaxial NFs has demonstrated excellent in promoting osseointegration and bacteria inhibitory efficacy. NFs coatings significantly enhanced the bonding between implant and bone remodeling within 8 weeks. The SA-induced osteomyelitis was prevented by the sustained release of Doxy from NFs. The capability of embedding numerous bio-components including proteins, growth factors, drugs, etc. enables NFs an effective solution to overcome the current challenged issue in Total joint replacement. In summary, we proposed PCL/PVA electrospun nanofibers as promising biomaterials that can be applied on

Material Science in Cervical Total Disc Replacement

Science.gov (United States)

Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

Material Science in Cervical Total Disc Replacement.

Science.gov (United States)

Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

2015-01-01

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Biofilm and dental implant: The microbial link

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Sangeeta Dhir

2013-01-01

Full Text Available Mouth provides a congenial environment for the growth of the microorganisms as compared to any other part of the human body by exhibiting an ideal nonshedding surface. Dental plaque happens to be a diverse community of the microorganisms found on the tooth surface. Periodontal disease and the peri-implant disease are specific infections that are originating from these resident microbial species when the balance between the host and the microbial pathogenicity gets disrupted. This review discusses the biofilms in relation to the peri-implant region, factors affecting its presence, and the associated treatment to manage this complex microbial colony. Search Methodology: Electronic search of the medline was done with the search words: Implants and biofilms/dental biofilm formation/microbiology at implant abutment interface/surface free energy/roughness and implant, periimplantitis/local drug delivery and dental implant. Hand search across the journals - clinical oral implant research, implant dentistry, journal of dental research, international journal of oral implantology, journal of prosthetic dentistry, perioodntology 2000, journal of periodontology were performed. The articles included in the review comprised of in vivo studies, in vivo (animal and human studies, abstracts, review articles.

The single-tooth implant treatment of congenitally missing maxillary lateral incisors using angled abutments: A clinical report

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Suleyman Hakan Tuna

2009-01-01

Full Text Available The maxillary lateral incisor is the second most common congenitally absent tooth. There are several treatment options for replacing the missing maxillary lateral incisor, including canine substitution, tooth-supported restoration, or single-tooth implant. Dental implants are an appropriate treatment option for replacing missing maxillary lateral incisor teeth in adolescents when their dental and skeletal development is complete. This case report presents the treatment of a patient with congenitally missing maxillary lateral incisors using dental implants with angled abutments.

In-situ photopolymerized and monitored implants: successful application to an intervertebral disc replacement

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Schmocker, Andreas M.; Khoushabi, Azadeh; Bourban, Pierre-Etienne; Schizas, Constantin; Pioletti, Dominique; Moser, Christophe

2016-02-01

Photopolymerization is a common method to harden materials initially in a liquid state. A surgeon can directly trigger the solidification of a dental implant or a bone or tissue filler by using ultra-violet light. Traditionally, photopolymerization has been used mainly in dentistry. Over the last decade advances in material development including a wide range of biocompatible gel- and cement-systems open up a new avenue for in-situ photopolymerization. We designed a miniaturized light probe where a photoactive material can be 1) mixed, pressurized and injected 2) photopolymerized or photoactivated and 3) monitored during the chemical reaction. The device enables surgeries to be conducted through a hole smaller than 500 μm in diameter. Using a combination of Raman and fluorescence spectroscopy, the current state of the photopolymerization was inferred and monitored in real time within an in-vitro tissue model. It was also possible to determine roughly the position of the probe within the tissue cavity by analysing the fluorescence signal. Using the technique hydrogels were successfully implanted into a bovine intervertebral disc model. Mechanical tests could not obstruct the functionality of the implant. Finally, the device was also used for other application such as the implantation of a hydrogel into an aneurysm tissue cavity which will be presented at the conference.

Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

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Albrecht Hartmann

Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

Aortic Annular Enlargement during Aortic Valve Replacement

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Selman Dumani

2016-09-01

Full Text Available In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

Intrinsic constraint of unlinked total elbow replacements--the ulnotrochlear joint.

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Kamineni, S; O'Driscoll, S W; Urban, M; Garg, A; Berglund, L J; Morrey, B F; An, K N

2005-09-01

Many unlinked total elbow replacement designs with radically differing articular geometries exist, suggesting that there is no consensus regarding an optimal design. A feature inherent to the articular design is the intrinsic constraint afforded to the joint by the implant. Our aim was to compare the intrinsic constraints of unlinked implants with that of the normal ulnotrochlear joint. We tested twelve cadaveric ulnotrochlear joints with a custom-made multiple-axis materials testing machine. With compressive loads ranging from 10 to 100 N, the joints were moved in either valgus or varus directions at 90 degrees of flexion. The ulnotrochlear components from a single example of five medium-sized unlinked elbow replacements (Ewald, Kudo, Pritchard ERS, Sorbie-Questor, and Souter-Strathclyde) were also tested. The recorded measurements included the torques and forces, angular displacement, and axial displacement of the humerus relative to the ulna. In general, the peak torque and the constraint ratio significantly increased with increasing compressive load for the implants as well as for the normal elbow. In valgus displacement, the Souter-Strathclyde implant had the highest and the Sorbie-Questor had the smallest peak torque and the Souter-Strathclyde had the highest and the Ewald had the smallest constraint ratio. In varus displacement, the Kudo had the highest and the Ewald had the smallest peak torque and constraint ratio. The constraint ratio is a characteristic that is useful for describing elbow joint behavior and for comparing the behavior of implants with that of the human elbow. Of the unlinked implants tested, the Souter-Strathclyde and Kudo prostheses most closely approximated the behavior of the human elbow joint. Implants that resemble the human elbow in appearance do not replicate normal behavior consistently, whereas other implants that do not resemble the human elbow closely do not deviate markedly from human behavior. Thus, much basic information

Replacing the nucleus pulposus of the intervertebral disk: prediction of suitable properties of a replacement material using finite element analysis.

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Meakin, J R

2001-03-01

An axisymmetric finite element model of a human lumbar disk was developed to investigate the properties required of an implant to replace the nucleus pulposus. In the intact disk, the nucleus was modeled as a fluid, and the annulus as an elastic solid. The Young's modulus of the annulus was determined empirically by matching model predictions to experimental results. The model was checked for sensitivity to the input parameter values and found to give reasonable behavior. The model predicted that removal of the nucleus would change the response of the annulus to compression. This prediction was consistent with experimental results, thus validating the model. Implants to fill the cavity produced by nucleus removal were modeled as elastic solids. The Poisson's ratio was fixed at 0.49, and the Young's modulus was varied from 0.5 to 100 MPa. Two sizes of implant were considered: full size (filling the cavity) and small size (smaller than the cavity). The model predicted that a full size implant would reverse the changes to annulus behavior, but a smaller implant would not. By comparing the stress distribution in the annulus, the ideal Young's modulus was predicted to be approximately 3 MPa. These predictions have implications for current nucleus implant designs. Copyright 2001 Kluwer Academic Publishers

Mitral valve replacement in infants and children 5 years of age or younger: Evolution in practice and outcome over three decades with a focus on supra-annular prosthesis implantation

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Tierney, Elif Seda Selamet; Pigula, Frank A.; Berul, Charles I.; Lock, James E.; del Nido, Pedro J.; McElhinney, Doff B.

2014-01-01

Objective Successful mitral valve replacement in young children is limited by the lack of small prosthetic valves. Supra-annular prosthesis implantation can facilitate mitral valve replacement with a larger prosthesis in children with a small annulus, but little is known about its effect on the outcomes of mitral valve replacement in young children. Methods One hundred eighteen children underwent mitral valve replacement at 5 years of age or younger from 1976–2006. Mitral valve replacement was supra-annular in 37 (32%) patients. Results Survival was 74% ± 4% at 1 year and 56% ± 5% at 10 years but improved over time (10-year survival of 83% ± 7% from 1994–2006). Factors associated with worse survival included earlier mitral valve replacement date, age less than 1 year, complete atrioventricular canal, and additional procedures at mitral valve replacement, but not supra-annular mitral valve replacement. As survival improved during our more recent experience, the risks of supra-annular mitral valve replacement became apparent; survival was worse among patients with a supra-annular prosthesis after 1991. A pacemaker was placed in 18 (15%) patients within 1 month of mitral valve replacement and was less likely in patients who had undergone supra-annular mitral valve replacement. Among early survivors, freedom from redo mitral valve replacement was 72% ± 5% at 5 years and 45% ± 7% at 10 years. Twenty-one patients with a supra-annular prosthesis underwent redo mitral valve replacement. The second prosthesis was annular in 15 of these patients and upsized in all but 1, but 5 required pacemaker placement for heart block. Conclusions Supra-annular mitral valve replacement was associated with worse survival than annular mitral valve replacement in our recent experience. Patients with supra-annular mitral valve replacement were less likely to have operative complete heart block but remained at risk when the prosthesis was subsequently replaced. PMID:18954636

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

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Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

2016-01-01

Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

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Min eLiu

2016-05-01

Full Text Available Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids versus snakes: (i the orientation of replacement teeth compared to the major tooth axis, (ii the occurrence of resorption pits, and (iii the mode of tooth implantation/attachment to the tooth bearing element. The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as

Peri-implant stress correlates with bone and cement morphology: Micro-FE modeling of implanted cadaveric glenoids.

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Wee, Hwabok; Armstrong, April D; Flint, Wesley W; Kunselman, Allen R; Lewis, Gregory S

2015-11-01

Aseptic loosening of cemented joint replacements is a complex biological and mechanical process, and remains a clinical concern especially in patients with poor bone quality. Utilizing high resolution finite element analysis of a series of implanted cadaver glenoids, the objective of this study was to quantify relationships between construct morphology and resulting mechanical stresses in cement and trabeculae. Eight glenoid cadavers were implanted with a cemented central peg implant. Specimens were imaged by micro-CT, and subject-specific finite element models were developed. Bone volume fraction, glenoid width, implant-cortex distance, cement volume, cement-cortex contact, and cement-bone interface area were measured. Axial loading was applied to the implant of each model and stress distributions were characterized. Correlation analysis was completed across all specimens for pairs of morphological and mechanical variables. The amount of trabecular bone with high stress was strongly negatively correlated with both cement volume and contact between the cement and cortex (r = -0.85 and -0.84, p implant-cortex distance. Contact between the cement and underlying cortex may dramatically reduce trabecular bone stresses surrounding the cement, and this contact depends on bone shape, cement amount, and implant positioning. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Contribution to implanted silicon layers and their annealing

International Nuclear Information System (INIS)

Combasson, J.-L.

1976-01-01

Defects created by boron implantation in silicon have been characterized by measuring the diffusion coefficient during annealing. Implanted impurity distributions were calculated after analyzing the hypotheses relating to charged particle slowing down through matter. Profiles are predicted with a good accuracy, by replacing occasionally the electronic stopping law by an empirical law. The asymmetries predicted are generally observed but deviations may occur for crystalline targets, or when the ion is heavy with regard to the substrate (in the event the Thomas-Fermi potential is not yet valid due to the high impact parameters). When deviations are neglected, the displacement cascade from implantation is represented by a damage profile proportional to the distribution of the Frenkel pairs. The annealing of the implanted layers is characterized by three annealing stages. The first one (400 deg C-600 deg C) is imputed to divacancy annealing associated to the formation and migration of boron-vacancy complexes. The second one (500 deg C-650 deg C) is characterized by the Watkins replacement mechanism. At high temperatures, when the annealing duration is longer than that of precipitation, interstitial loops are dissolved, and the thermal diffusion of boron atoms involves the vacancy mechanism of thermal diffusion [fr

Material Science in Cervical Total Disc Replacement

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Martin H. Pham

2015-01-01

Full Text Available Current cervical total disc replacement (TDR designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti, and cobalt-chrome (CoCr. These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Implantable batteryless device for on-demand and pulsatile insulin administration

Science.gov (United States)

Lee, Seung Ho; Lee, Young Bin; Kim, Byung Hwi; Lee, Cheol; Cho, Young Min; Kim, Se-Na; Park, Chun Gwon; Cho, Yong-Chan; Choy, Young Bin

2017-04-01

Many implantable systems have been designed for long-term, pulsatile delivery of insulin, but the lifetime of these devices is limited by the need for battery replacement and consequent replacement surgery. Here we propose a batteryless, fully implantable insulin pump that can be actuated by a magnetic field. The pump is prepared by simple-assembly of magnets and constituent units and comprises a drug reservoir and actuator equipped with a plunger and barrel, each assembled with a magnet. The plunger moves to noninvasively infuse insulin only when a magnetic field is applied on the exterior surface of the body. Here we show that the dose is easily controlled by varying the number of magnet applications. Also, pump implantation in diabetic rats results in profiles of insulin concentration and decreased blood glucose levels similar to those observed in rats treated with conventional subcutaneous insulin injections.

Iso-surface volume rendering for implant surgery

NARCIS (Netherlands)

van Foreest-Timp, Sheila; Lemke, H.U.; Inamura, K.; Doi, K.; Vannier, M.W.; Farman, A.G.

2001-01-01

Many clinical situations ask for the simultaneous visualization of anatomical surfaces and synthetic meshes. Common examples include hip replacement surgery, intra-operative visualization of surgical instruments or probes, visualization of planning information, or implant surgery. To be useful for

Optimal Implantation Depth and Adherence to Guidelines on Permanent Pacing to Improve the Results of Transcatheter Aortic Valve Replacement With the Medtronic CoreValve System: The CoreValve Prospective, International, Post-Market ADVANCE-II Study.

Science.gov (United States)

Petronio, Anna S; Sinning, Jan-Malte; Van Mieghem, Nicolas; Zucchelli, Giulio; Nickenig, Georg; Bekeredjian, Raffi; Bosmans, Johan; Bedogni, Francesco; Branny, Marian; Stangl, Karl; Kovac, Jan; Schiltgen, Molly; Kraus, Stacia; de Jaegere, Peter

2015-05-01

The aim of the CoreValve prospective, international, post-market ADVANCE-II study was to define the rates of conduction disturbances and permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement with the Medtronic CoreValve System (Minneapolis, Minnesota) using optimized implantation techniques and application of international guidelines on cardiac pacing. Conduction disturbances are a frequent complication of transcatheter aortic valve replacement. The rates of PPI in the published reports vary according to bioprosthesis type and the indications for PPI. The primary endpoint was the 30-day incidence of PPI with Class I/II indications when the Medtronic CoreValve System was implanted at an optimal depth (≤6 mm below the aortic annulus). The timing and resolution of all new-onset conduction disturbances were analyzed. A total of 194 patients were treated. The overall rate of PPI for Class I/II indications was 18.2%. An optimal depth was reached in 43.2% of patients, with a nonsignificantly lower incidence of PPI in patients with depths ≤6 mm, compared with those with deeper implants (13.3% vs. 21.1%; p = 0.14). In a paired analysis, new-onset left bundle branch block and first-degree atrioventricular block occurred in 45.4% and 39.0% of patients, respectively, and resolved spontaneously within 30 days in 43.2% and 73.9%, respectively. In patients with new PPI, the rate of intrinsic sinus rhythm increased from 25.9% at 7 days to 59.3% at 30 days (p = 0.004). Optimal Medtronic CoreValve System deployment and adherence to international guidelines on cardiac pacing are associated with a lower rate of new PPI after transcatheter aortic valve replacement, compared with results reported in previous studies. (CoreValve Advance-II Study: Prospective International Post-Market Study [ADVANCE II]; NCT01624870). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Management of Broken Dental Implant Abutment in a Patient with Bruxism: A Rare Case Report and Review of Literature.

Science.gov (United States)

Al-Almaie, Saad

2017-01-01

This rare case report describes prosthodontic complications resulting from a dental implant was placed surgically more distally in the area of the missing mandibular first molar with a cantilever effect and a crest width of >12 mm in a 59-year-old patient who had a history of bruxism. Fracture of abutment is a common complication in implant was placed in area with high occlusal forces. Inability to remove the broken abutment may most often end up in discarding the implant. Adding one more dental implant mesially to the previously placed implant, improvisation of technique to remove the broken abutment without sacrificing the osseointegrated dental implant, fabrication with cemented custom-made abutment to replace the broken abutment for the first implant, and the use of the two implants to replace a single molar restoration proved reliable and logical treatment solutions to avoid these prosthodontic complications.

Management of broken dental implant abutment in a patient with bruxism: A rare case report and review of literature

Directory of Open Access Journals (Sweden)

Saad Al-Almaie

2017-01-01

Full Text Available This rare case report describes prosthodontic complications resulting from a dental implant was placed surgically more distally in the area of the missing mandibular first molar with a cantilever effect and a crest width of >12 mm in a 59-year-old patient who had a history of bruxism. Fracture of abutment is a common complication in implant was placed in area with high occlusal forces. Inability to remove the broken abutment may most often end up in discarding the implant. Adding one more dental implant mesially to the previously placed implant, improvisation of technique to remove the broken abutment without sacrificing the osseointegrated dental implant, fabrication with cemented custom-made abutment to replace the broken abutment for the first implant, and the use of the two implants to replace a single molar restoration proved reliable and logical treatment solutions to avoid these prosthodontic complications.

Additive manufacturing: From implants to organs

African Journals Online (AJOL)

Additive manufacturing (AM) constructs 3D objects layer by layer under computer control from 3D models. 3D printing is one ... anatomical models for surgery planning, and design and construction ... production of implants, particularly to replace bony structures, is ... Manufactured organs are, however, an elusive goal.

Basic research on maxillofacial implants

International Nuclear Information System (INIS)

Matsui, Yoshiro

2001-01-01

Osseointegrated implants have begun to be used not only in general practice in dentistry but also in various clinical situations in the maxillofacial region. The process has yielded three problems: the spread of application, new materials and diagnostic methods, and management for difficult situations. This paper presents basic data and clinical guidelines for new applications, it investigates the characteristics of the materials and the usefulness of a new diagnostic method, and it studies effective techniques for difficult cases. The results obtained are as follows: Investigations into the spreading application. The lateral and superior orbital rim have sufficient bone thickness and width for the implant body to be placed. Osseointegrated implants, especially by the fixed bridge technique, are not recommended in the craniofacial bone and jaws of young children. Implant placement into bone after/before irradiation must be performed in consideration of impaired osteogenesis, the decrease of trabecular bone, and the time interval between implantation and irradiation. Investigations into materials and diagnostic methods. Hydroxyapatite-coated and titanium implants should be selected according to the characteristics of the materials. A dental simulating soft may also be applicable in the craniofacial region. Investigations into the management of difficult cases. Hyperbaric oxygen therapy (HBO), bone morphogenetic protein (BMP), and tissue engineering should be useful for improving the quality and increasing the quantity of bone where implants are placed. Soft tissue around implants placed in the reconstructed area should be replaced with mucosal tissue. The data obtained here should be useful for increasing the efficiency of osseointegrated implants, but further basic research is required in the future. (author)

Basic research on maxillofacial implants

Energy Technology Data Exchange (ETDEWEB)

Matsui, Yoshiro [Showa Univ., Tokyo (Japan). School of Dentistry

2001-11-01

Osseointegrated implants have begun to be used not only in general practice in dentistry but also in various clinical situations in the maxillofacial region. The process has yielded three problems: the spread of application, new materials and diagnostic methods, and management for difficult situations. This paper presents basic data and clinical guidelines for new applications, it investigates the characteristics of the materials and the usefulness of a new diagnostic method, and it studies effective techniques for difficult cases. The results obtained are as follows: Investigations into the spreading application. The lateral and superior orbital rim have sufficient bone thickness and width for the implant body to be placed. Osseointegrated implants, especially by the fixed bridge technique, are not recommended in the craniofacial bone and jaws of young children. Implant placement into bone after/before irradiation must be performed in consideration of impaired osteogenesis, the decrease of trabecular bone, and the time interval between implantation and irradiation. Investigations into materials and diagnostic methods. Hydroxyapatite-coated and titanium implants should be selected according to the characteristics of the materials. A dental simulating soft may also be applicable in the craniofacial region. Investigations into the management of difficult cases. Hyperbaric oxygen therapy (HBO), bone morphogenetic protein (BMP), and tissue engineering should be useful for improving the quality and increasing the quantity of bone where implants are placed. Soft tissue around implants placed in the reconstructed area should be replaced with mucosal tissue. The data obtained here should be useful for increasing the efficiency of osseointegrated implants, but further basic research is required in the future. (author)

Precision of fit between implant impression coping and implant replica pairs for three implant systems.

Science.gov (United States)

Nicoll, Roxanna J; Sun, Albert; Haney, Stephan; Turkyilmaz, Ilser

2013-01-01

The fabrication of an accurately fitting implant-supported fixed prosthesis requires multiple steps, the first of which is assembling the impression coping on the implant. An imprecise fit of the impression coping on the implant will cause errors that will be magnified in subsequent steps of prosthesis fabrication. The purpose of this study was to characterize the 3-dimensional (3D) precision of fit between impression coping and implant replica pairs for 3 implant systems. The selected implant systems represent the 3 main joint types used in implant dentistry: external hexagonal, internal trilobe, and internal conical. Ten impression copings and 10 implant replicas from each of the 3 systems, B (Brånemark System), R (NobelReplace Select), and A (NobelActive) were paired. A standardized aluminum test body was luted to each impression coping, and the corresponding implant replica was embedded in a stone base. A coordinate measuring machine was used to quantify the maximum range of displacement in a vertical direction as a function of the tightening force applied to the guide pin. Maximum angular displacement in a horizontal plane was measured as a function of manual clockwise or counterclockwise rotation. Vertical and rotational positioning was analyzed by using 1-way analysis of variance (ANOVA). The Fisher protected least significant difference (PLSD) multiple comparisons test of the means was applied when the F-test in the ANOVA was significant (α=.05). The mean and standard deviation for change in the vertical positioning of impression copings was 4.3 ±2.1 μm for implant system B, 2.8 ±4.2 μm for implant system R, and 20.6 ±8.8 μm for implant system A. The mean and standard deviation for rotational positioning was 3.21 ±0.98 degrees for system B, 2.58 ±1.03 degrees for system R, and 5.30 ±0.79 degrees for system A. The P-value for vertical positioning between groups A and B and between groups A and R was <.001. No significant differences were found for

Bone replacement following dental trauma prior to implant surgery - present status

NARCIS (Netherlands)

Hallman, Mats; Mordenfeld, Arne; Strandkvist, Tomas

Dento-alveolar trauma often leads to a need for reconstruction of the alveolar crest before an implant can be placed. Although autogenous bone grafts is considered the 'gold standard', this may be associated with patient morbidity and graft resorption. Consequently, the use of bone substitutes has

Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

Science.gov (United States)

Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

2013-01-01

Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip

Elders with implant overdentures: a 22-year clinical report.

Science.gov (United States)

Alsabeeha, Nabeel H M

2012-09-01

To report on the long-term survival and prosthodontic maintenance of two edentulous adults with mandibular overdentures supported by hydroxyapatite (HA)-coated implants. Mandibular implant overdentures are a successful treatment option with positive impact on the quality of life of elderly edentulous adults. Long-term survival of the implants requires continued rigorous prosthodontic maintenance. Two elderly edentulous adults with mandibular overdentures supported by 2 HA-coated implants were presented for prosthodontic rehabilitation after 22 years of placement. The implants were osseo-integrated and surviving at presentation based on accepted criteria. The mandibular implant overdentures suffered recurrent loss of retention and stability. Prosthodontic treatment involving the replacement of defective attachment systems and construction of new sets of mandibular implant overdentures opposing complete maxillary dentures is presented. The long-term survival of mandibular 2-implant overdentures requires continued prosthodontic maintenance. A conservative approach in the rehabilitation of two older edentulous adults with mandibular 2-implant overdentures was described including proper selection of attachment systems. © 2012 The Gerodontology Society and John Wiley & Sons A/S.

Spine imaging after lumbar disc replacement: pitfalls and current recommendations

Directory of Open Access Journals (Sweden)

Sandén Bengt

2009-07-01

Full Text Available Abstract Background Most lumbar artificial discs are still composed of stainless steel alloys, which prevents adequate postoperative diagnostic imaging of the operated region when using magnetic resonance imaging (MRI. Thus patients with postoperative radicular symptoms or claudication after stainless steel implants often require alternative diagnostic procedures. Methods Possible complications of lumbar total disc replacement (TDR are reviewed from the available literature and imaging recommendations given with regard to implant type. Two illustrative cases are presented in figures. Results Access-related complications, infections, implant wear, loosening or fracture, polyethylene inlay dislodgement, facet joint hypertrophy, central stenosis, and ankylosis of the operated segment can be visualised both in titanium and stainless steel implants, but require different imaging modalities due to magnetic artifacts in MRI. Conclusion Alternative radiographic procedures should be considered when evaluating patients following TDR. Postoperative complications following lumbar TDR including spinal stenosis causing radiculopathy and implant loosening can be visualised by myelography and radionucleotide techniques as an adjunct to plain film radiographs. Even in the presence of massive stainless steel TDR implants lumbar radicular stenosis and implant loosening can be visualised if myelography and radionuclide techniques are applied.

Comparative Effectiveness Research of Adjunctive Methods in Controlling Peri-Implant Mucositis Intervention A Systematic Review Analysis

OpenAIRE

Javadi, Shadi

2017-01-01

Introduction and Objective: Peri-implant mucositis is a very common condition affecting the gingival tissue around dental implants. It is an inflammation of the tissues, characterized by bleeding on probing around the implant. This condition is the initial step of a more severe condition called peri-implantitis, which is very difficult to treat. With increased number of implant placements in patients, the length of time each dental implant is supposed to serve, and the price of replacing the ...

Long time follow up of implant therapy and treatment of peri-implantitis.

Science.gov (United States)

Roos-Jansåker, Ann-Marie

2007-01-01

Dental implants have become an often used alternative to replace missing teeth, resulting in an increasing percentage of the adult population with implant supported prosthesis. Although favourable long-term results of implant therapy have been reported, infections occur. Until recently few reports included data on peri-implant infections, possibly underestimating this complication of implant treatment. It is possible that some infections around implants develop slowly and that with time peri-implantitis will be a common complication to implant therapy as an increasing number of patients have had their implants for a long time (>10 years). Data on treatment of peri-implant lesions are scarce leaving the clinician with limited guidance regarding choice of treatment. The aim of this thesis was to study the frequency of implant loss and presence of peri-implant lesions in a group of patients supplied with Brånemark implants 9-14 years ago, and to relate these events to patient and site specific characteristics. Moreover three surgical treatment modalities for peri-implantitis were evaluated. The thesis is based on six studies; Studies I-III included 218 patients and 1057 implants followed for 9-14 years evaluating prevalence of, and factors related to implant loss (Paper I) and prevalence of peri-implant infections and related factors (Paper I-III). Study IV is a review describing different treatment modalities of peri-implant infections. Study V is a prospective cohort study involving 36 patients and 65 implants, evaluating the use of a bone substitute with or without the use of a resorbable membrane. Study VI is a case series with 12 patients and 16 implants, evaluating a bone substitute in combination with a resorbable membrane and submerged healing. This thesis demonstrated that: After 9-14 years the survival rates of dental implants are high (95.7%). Implant loss seems to cluster within patients and are related to periodontitis evidenced as bone loss on

[Late complications following Björk-Shiley and St. Jude Medical heart valve replacement].

Science.gov (United States)

Horstkotte, D; Körfer, R; Budde, T; Haerten, K; Schulte, H D; Bircks, W; Loogen, F

1983-05-01

Valve-related complications after Björk-Shiley mitral (n = 475), aortic (n = 424), or mitral-aortic implantation (n = 119) were compared to complications after St. Jude mitral (n = 173), aortic (n = 152), and St. Jude mitral and aortic (n = 63) replacements. The 1,018 consecutive patients with Björk-Shiley valves had been operated upon between 1974 and 1982, those with St. Jude valves between 1978 and 1982. All patients were placed on anticoagulant therapy with phenprocoumon early after operation and no significant intergroup differences in the effectiveness of the anticoagulant therapy were found. At a comparable follow-up time of approximately 23 months, 24 major thromboembolic episodes were observed after Björk-Shiley mitral (BSM) and 3 after St. Jude mitral valve implantation (SJM), corresponding to a thromboembolic rate of 2.82/100 patient years with BSM and 0.93/100 patient years with SJM. After aortic valve replacements, 1.93 events in 100 patient years occurred after Björk-Shiley aortic (BSA) and 0.73 after St. Jude aortic implantation (SJA). In patients with double valve replacements, these rates were 3.2 (BSM + BSA) and 0.88 (SJM + SJA), respectively. The cerebral vessels were involved in 52% and the arteries of the extremities in 22% of these major events. Six Björk-Shiley prostheses had to be replaced because of valve thrombosis. The overall incidence of severe hemorrhagic complications was 2.94/100 patient years in BSM and 1.79 in SJM. After aortic valve replacement, we found rates of 1.80/100 patient years (BSA) and 2.57/100 patient years (SJA), respectively. Intravascular hemolysis no longer seems to be a significant clinical problem. However, indications of red cell damage after heart valve replacement were significantly greater in patients with perivalvular leakage, valve thrombosis, or dysfunction than in those with normally functioning prostheses. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2

Presence of Biofilms on Polyurethane-Coated Breast Implants: Preliminary Results.

Science.gov (United States)

Rieger, Ulrich M; Djedovic, Gabriel; Pattiss, Alexander; Raschke, Gregor F; Frei, Reno; Pierer, Gerhard; Trampuz, Andrej

2016-01-01

Polyurethane-coated breast implants seem to be associated with lower medium- and long-term capsular contracture rates in comparison to textured or smooth implant surfaces. Although the etiology of capsular contracture is uncertain, bacterial biofilms have been suggested to trigger chronic peri-implant inflammation, eventually leading to capsular contracture. It is unknown whether polyurethane-coated implants are less prone to biofilm colonization than other implant surfaces. We extracted data from patient records included in a prospective cohort between 2008 and 2011. All patients who underwent removal of polyurethane-coated implants were included in this current study and screened for presence of biofilms by sonication. In addition, implant- and patient-related data were analyzed. Of the ten included polyurethane-coated breast implants, six had been inserted for reconstructive purposes and four for aesthetic reasons. The median implant indwelling time was 28.3 mo. Overall, sonication cultures were positive in 50% of implants. Propionibacterium acnes and coagulase-negative staphylococci were the predominant pathogens isolated from biofilm cultures. Like other implant surfaces, polyurethane-coated implants are prone to biofilm colonization. Further investigations are needed to determine why capsular contracture rates seem to be lower in polyurethane implants than in other implant surfaces. Notably, in this study, 40% of the implants were explanted from breasts with severe capsular contracture.

Single-tooth replacement: factors affecting different prosthetic treatment modalities

Directory of Open Access Journals (Sweden)

Al-Quran Firas A

2011-12-01

Full Text Available Abstract Background The choice between several treatment options for replacing a single missing tooth is influenced by clinical, dentist- and patient-immanent factors. This study aimed to determine the patient factors that would affect the treatment decision to replace a single missing tooth and to assess the satisfaction with several options. Method 200 volunteers involved (121 females and 79 males divided into four groups, Group A: consisted of patients with conventional fixed partial dentures or patients with resin bonded fixed partial dentures. Group B: consisted of patients who received removable partial dentures while Group C: consisted of patients who received a single implant supported crown, and a control group D: consisted of patients who received no treatment. Data were collected using a questionnaire. Results The highest percentage of males within groups (58% was within the removable prostheses category. The majority of the subjects in the study reported that the main reason for replacing a missing tooth was for esthetic and function. Most important factor affecting the choice between treatment modalities was damaging the neighboring teeth. Pain, post operative sensitivity and dental phobia were important factors in choosing the prosthesis type and affected the control group patients not to have any treatment. The highest satisfaction percentage among groups studied was recorded for dental implants then FPD groups, while the least percentage were in both the control and RPD groups, for all aspects of function, esthetic and speech efficiency. Conclusions The final choice between FPD, RPD and implant depended on several factors which affected the decision making; among these is cost and patients' awareness of the different treatment options.

Dual-modal photoacoustic and ultrasound imaging of dental implants

Science.gov (United States)

Lee, Donghyun; Park, Sungjo; Kim, Chulhong

2018-02-01

Dental implants are common method to replace decayed or broken tooth. As the implant treatment procedures varies according to the patients' jawbone, bone ridge, and sinus structure, appropriate examinations are necessary for successful treatment. Currently, radiographic examinations including periapical radiology, panoramic X-ray, and computed tomography are commonly used for diagnosing and monitoring. However, these radiographic examinations have limitations in that patients and operators are exposed to radioactivity and multiple examinations are performed during the treatment. In this study, we demonstrated photoacoustic (PA) and ultrasound (US) combined imaging of dental implant that can lower the total amount of absorbed radiation dose in dental implant treatment. An acoustic resolution PA macroscopy and a clinical PA/US system was used for dental implant imaging. The acquired dual modal PA/US imaging results support that the proposed photoacoustic imaging strategy can reduce the radiation dose rate during dental implant treatment.

[Clinical evaluation of the ceramic femoral component used for reconstruction of total knee replacement].

Science.gov (United States)

Vavrík, P; Landor, I; Denk, F

2008-12-01

The study evaluates mid-term results of total knee replacement with a zirconia ceramic (ZrO2) femoral component. The evaluated group comprised 20 knees in 19 patients (4 men and 15 women). In one patient the replacement was performed bilaterally. Two patients had in the contralateral knee the same type of prosthesis with a femoral chrome-cobalt component.The mean age at the time of operation was 65.2 years (range, 38-81 years).The primary indication was 14 times osteoarthritis and 5 times rheumatoid arthritis. The average follow-up period was 6.5 years (range, 2.1-8.5 years). Patients included in the study regardless of age, body mass and the basic diagnosis, agreed with the use of the ceramic femoral component. The evaluation covered a range of motion, mechanical axis, joint stability, pain, swelling, ability to walk on level ground and on stairs, subjective satisfaction (EULAR Knee Chart). Radiograph were assessed at one year intervals in two projections to identify the incidence of radiolucency around the implant. The Kaplan-Meier survival curve was used and compared with the survival curve in identical chrome-cobalt implants. At he final follow-up, 14 knees were evaluated, because 3 patients died without any connection with the implant, in one case the tibial component migrated due to necrosis of the tibial condyle in a patient with RA and two implants had to be revised and replaced due to polyethylene wear. No infection or negative tissue reaction was recorded in the evaluated group. The average flexion range was 109 degrees. All knees were stable and without swelling, in two cases there occurred slight femoropatellar pain. Twelve patients were fully satisfied, 2 patients were satisfied with a certain reservation. The differences in the course of the survival curves of chrome-cobalt and ceramic implants were statistically insignificant. Although the use of zirconia ceramics in vitro reduces the amount of polyethylene wear, the clinical outcomes of total knee

Osteomyelitis of the Mandible after Dental Implants in an Immunocompetent Patient

Directory of Open Access Journals (Sweden)

Matthieu Balanger

2017-01-01

Full Text Available Dental implants are now broadly used to replace missing teeth, and the presence of infectious complications is rising. Dental implant therapy as a local risk factor for the onset of osteomyelitis and its management have not been widely explored. Here, we report an unusual case of mandibular suppurative osteomyelitis caused by Streptococcus intermedius in a healthy and immunocompetent patient secondary to mandibular implants. We describe how surgery combined with systemic application of antibiotics allowed conservation of the dental implants in the mandibular bone, discuss the probable source of contamination, and present the follow-up of the osteomyelitis.

Machine learning techniques for the optimization of joint replacements: Application to a short-stem hip implant.

Science.gov (United States)

Cilla, Myriam; Borgiani, Edoardo; Martínez, Javier; Duda, Georg N; Checa, Sara

2017-01-01

Today, different implant designs exist in the market; however, there is not a clear understanding of which are the best implant design parameters to achieve mechanical optimal conditions. Therefore, the aim of this project was to investigate if the geometry of a commercial short stem hip prosthesis can be further optimized to reduce stress shielding effects and achieve better short-stemmed implant performance. To reach this aim, the potential of machine learning techniques combined with parametric Finite Element analysis was used. The selected implant geometrical parameters were: total stem length (L), thickness in the lateral (R1) and medial (R2) and the distance between the implant neck and the central stem surface (D). The results show that the total stem length was not the only parameter playing a role in stress shielding. An optimized implant should aim for a decreased stem length and a reduced length of the surface in contact with the bone. The two radiuses that characterize the stem width at the distal cross-section in contact with the bone were less influential in the reduction of stress shielding compared with the other two parameters; but they also play a role where thinner stems present better results.

Surface characterization of titanium based dental implants; Caracterizacao de implantes odontologicos a base de titanio

Energy Technology Data Exchange (ETDEWEB)

Castilho, Guilherme Augusto Alcaraz

2006-07-01

Dental implantology uses metallic devices made of commercially pure titanium in order to replace lost teeth. Titanium presents favorable characteristics as bio material and modern implants are capable of integrate, witch is the union between bone and implant without fibrous tissue development. Three of the major Brazilian implant manufacturers were chosen to join the study. A foreign manufacturer participated as standard. The manufacturers had three specimens of each implant with two different surface finishing, as machined and porous, submitted to analysis. Surface chemical composition and implant morphology were analyzed by X-ray photoelectron spectroscopy (XP S), scanning electron microscopy (SEM) and microprobe. Implant surface is mainly composed of titanium, oxygen and carbon. Few contaminants commonly present on implant surface were found on samples. Superficial oxide layer is basically composed of titanium dioxide (TiO{sub 2}), another oxides as Ti O and Ti{sub 2}O{sub 3} were also found in small amount. Carbon on implant surface was attributed to manufacturing process. Nitrogen, Phosphorous and Silicon appeared in smaller concentration on surface. There was no surface discrepancy among foreign and Brazilian made implants. SEM images were made on different magnification, 35 X to 3500 X, and showed similarity among as machined implants. Porous surface finishing implants presented distinct morphology. This result was attributed to differences on manufacturing process. Implant bioactivity was accessed through immersion on simulated body solution (SBF) in order to verify formation of an hydroxyapatite (HA) layer on surface. Samples were divided on three groups according to immersion time: G1 (7 days), G2 (14 days), G3 (21 days), and deep in SBF solution at 37 deg C. After being removed from solution, XPS analyses were made and then implants have been submitted to microprobe analysis. XPS showed some components of SBF solution on sample surface but microprobe

Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

Science.gov (United States)

2016-01-01

Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-apically. In the control group, horizontal external mattress sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 1 and 3 months. Results Healing was uneventful in both groups. The difference of width between baseline and 1 month was −0.26±0.85 mm in the test group, without any statistical significance (P=0.137). Meanwhile, the corresponding difference in the control group was −0.74±0.73 mm and it showed statistical significance (Pprefabricated implant-retained stent was shown to be effective in the preservation of the keratinized mucosa around implants and it was simple and straightforward in comparison to the horizontal external mattress suture technique. PMID:27800215

Maxillary implant-retained partial overdenture with Dolder bar attachment: a clinical report.

Science.gov (United States)

Kim, Hyeongil; Buhite, Robert J; Monaco, Edward A

2015-03-01

This article describes a technique for maintaining a maxillary Kennedy III partial removable dental prosthesis design in a patient who had non-restorable failing abutments by replacing the abutments with dental implants. Two implants were placed immediately after extraction of the abutment teeth in the anterior maxilla. After the implants were fully integrated, a Dolder bar attachment was fitted onto the implants. A new maxillary partial removable dental prosthesis was fabricated using the implants and the remaining natural teeth as abutments to restore function and esthetics. With the aid of dental implants, this Kennedy III maxillary removable dental prosthesis design could provide additional retention and support by promoting cross-arch stability and tissue, implant and tooth support. The patient's satisfaction was significantly increased.

Alendronate treatment in the revision setting, with and without controlled implant motion

DEFF Research Database (Denmark)

Søballe, Kjeld; Chen, Xinqian; Jensen, Thomas B

2007-01-01

Introduction Bisphosphonates have been proposed to delay or prevent loosening of joint replacement implants by reducing bone resorption. It is known, however, that implant motion prevents the bone anchorage necessary to maintain secure implant fixation. Methods We used our experimental implant...... conditions, even with alendronate. With alendronate and stabilized implants, increased bone was observed near the sclerotic shell of the revision cavity, but it was reduced with alendronate when the implant was unstable. Interpretation Our findings suggest that it may be difficult for alendronate...... administration alone to rescue implants that are already loose. In implants that have not progressed to loosening, alendronate may increase bone density at the border with the sclerotic shell, but the effect of this bone in delaying eventual loosening is not known. Udgivelsesdato: 2007-Dec...

Electrical and crystallographic evaluation of SOS implanted with silicon and/or oxygen

International Nuclear Information System (INIS)

Yamamoto, Y.; Kobayashi, H.; Takahashi, T.; Inada, T.

1985-01-01

RBS and Hall measurements have revealed that the formation of an amorphous laer in SOS near in the Si/sapphire interface by oxygen implantation at 130 K followed by regrowth by thermal annealing above 800 0 C for 20 min in N 2 is effective in improving crystalline quality and Hall mobility as well as in increasing activation of implanted P. The temperature dependence of the mobility was measured. The mobility increased by 80% and 40% at 77 K and RT, respectively, after improvement in crystalline quality. The costly low temperature implantation of O can be replaced with dual implantation of Si and O; formation of an amorphous layer by Si implantation and Al gettering by oxygen implantation. (orig.)

The use of synthetic ligaments in the design of an enhanced stability total knee joint replacement.

Science.gov (United States)

Stokes, Michael D; Greene, Brendan C; Pietrykowski, Luke W; Gambon, Taylor M; Bales, Caroline E; DesJardins, John D

2018-03-01

Current total knee replacement designs work to address clinically desired knee stability and range of motion through a balance of retained anatomy and added implant geometry. However, simplified implant geometries such as bearing surfaces, posts, and cams are often used to replace complex ligamentous constraints that are sacrificed during most total knee replacement procedures. This article evaluates a novel total knee replacement design that incorporates synthetic ligaments to enhance the stability of the total knee replacement system. It was hypothesized that by incorporating artificial cruciate ligaments into a total knee replacement design at specific locations and lengths, the stability of the total knee replacement could be significantly altered while maintaining active ranges of motion. The ligament attachment mechanisms used in the design were evaluated using a tensile test, and determined to have a safety factor of three with respect to expected ligamentous loading in vivo. Following initial computational modeling of possible ligament orientations, a physical prototype was constructed to verify the function of the design by performing anterior/posterior drawer tests under physiologic load. Synthetic ligament configurations were found to increase total knee replacement stability up to 94% compared to the no-ligament case, while maintaining total knee replacement flexion range of motion between 0° and 120°, indicating that a total knee replacement that incorporates synthetic ligaments with calibrated location and lengths should be able to significantly enhance and control the kinematic performance of a total knee replacement system.

Early micromovement of the Articular Surface Replacement (ASR) femoral component

DEFF Research Database (Denmark)

Penny, J O; Ding, M; Varmarken, J E

2012-01-01

Radiostereometric analysis (RSA) can detect early micromovement in unstable implant designs which are likely subsequently to have a high failure rate. In 2010, the Articular Surface Replacement (ASR) was withdrawn because of a high failure rate. In 19 ASR femoral components, the mean micromovement...

Soft Tissue Surgical Procedures for Optimizing Anterior Implant Esthetics

Science.gov (United States)

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

2015-01-01

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

Comparative effectiveness of ceramic-on-ceramic implants in stemmed hip replacement: a multinational study of six national and regional registries.

Science.gov (United States)

Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy

2014-12-17

The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard

Patient and implant survival following joint replacement because of metastatic bone disease

DEFF Research Database (Denmark)

Sørensen, Michala S; Gregersen, Kristine G; Grum-Schwensen, Tomas

2013-01-01

Patients suffering from a pathological fracture or painful bony lesion because of metastatic bone disease often benefit from a total joint replacement. However, these are large operations in patients who are often weak. We examined the patient survival and complication rates after total joint...... replacement as the treatment for bone metastasis or hematological diseases of the extremities....

Contact Mechanics and Failure Modes of Compliant Polymeric Bearing Materials for Knee Cartilage Replacement

Science.gov (United States)

Tohfafarosh, Mariya Shabbir

Osteoarthritis (OA) is the most common cause of disability affecting millions of people worldwide. Total knee replacement is the current state-of-the-art treatment to alleviate pain and improve mobility among patients in the late stage of knee OA. The current gold standard materials for total knee arthroplasty are cobalt-chromium and ultra-high molecular weight polyethylene (UHMWPE). However, wear debris and implant loosening-related revision persists; consequently, total knee replacements are not universally recommended for all patient subgroups with OA. This work explores the potential of using compliant polymeric materials in knee cartilage replacement devices, which are closer in lubrication and mechanical properties of articular cartilage, to prevent excessive removal of underlying bone and prolong the need for a total knee replacement. Two materials investigated in this thesis are polycarbonate urethane, Bionate 80A, and a novel hydrogel, Cyborgel, both of which have shown promising wear and lubrication properties under physiological loads. Polycarbonate urethane has been previously tested for the effects of gamma sterilization and has shown no significant changes in its mechanical strength or chemical bonds. Since an important aspect of medical device development is the sterilization process, this thesis first evaluated the effect of 30-35 kGy electron beam and gamma radiation on the polymer swell ratio, and the mechanical, chemical and tribological behavior of the novel hydrogel. Three different formulations were mechanically tested, and biphasic material properties were identified using finite element analysis. Fourier transform infrared spectroscopy was used to investigate chemical changes, while the wear properties were tested for 2 million cycles in bovine serum. The results showed no significant difference (p > 0.05) in the swell ratio, mechanical and tribological properties of the electron beam and gamma sterilized hydrogel sample as compared to the

Cobalt Alloy Implant Debris Induces Inflammation and Bone Loss Primarily through Danger Signaling, Not TLR4 Activation: Implications for DAMP-ening Implant Related Inflammation

OpenAIRE

Samelko, Lauryn; Landgraeber, Stefan; McAllister, Kyron; Jacobs, Joshua; Hallab, Nadim James

2016-01-01

Cobalt alloy debris has been implicated as causative in the early failure of some designs of current total joint implants. The ability of implant debris to cause excessive inflammation via danger signaling (NLRP3 inflammasome) vs. pathogen associated pattern recognition receptors (e.g. Toll-like receptors; TLRs) remains controversial. Recently, specific non-conserved histidines on human TLR4 have been shown activated by cobalt and nickel ions in solution. However, whether this TLR activation ...

Special features of total knee replacement in hemophilia.

Science.gov (United States)

Rodriguez-Merchan, Emerito Carlos

2013-12-01

Total knee replacement is an operation frequently needed by hemophilia patients, which greatly improves their quality of life. This operation, however, carries a higher risk of bleeding and infection for hemophiliacs than it does for osteoarthritis sufferers. It is advisable to implant prosthetic components using antibiotic-loaded cement. It is essential to maintain a level of 100% of the replacement clotting factor for 2 weeks. Hematological treatment must be established, depending on the patient's factor levels and other pharmacokinetic parameters such as recovery and half-life, optimal doses and treatment time. It is preferable to use general anesthesia due to the risk of spinal bleeding. The lifespan of total knee replacement in hemophilic patients is shorter than in patients with osteoarthritis because of the increased risk of infection.

Fracture of a HTR-PMI cranioplastic implant after severe TBI.

Science.gov (United States)

López González, Antonio; Pérez Borredá, Pedro; Conde Sardón, Rebeca

2015-02-01

A 13-year-old girl with a large left fronto-parietal hard-tissue replacement patient-matched implant (HTR®-PMI) cranioplasty-since she suffered from a traumatic brain injury (TBI) 6 years ago-had a new severe TBI that detached and fractured the implant as well as caused a left subdural hematoma and a large frontal contusion. The hematoma and contusion were removed and the implant was substituted by a provisional titanium mesh. To the best of our knowledge, this is the first case reported about an HTR®-PMI fracture. It is theorized that the bone ingrowth into the macroporous implants, like those of hydroxyapatite, gives strength and resistance to the implant. But in the case we describe, no macroscopic bone ingrowth was detected 6 years after implantation and the traumatic force that impacted over the cranioplasty exceeded its properties.

Optimization of hip joint replacement location to decrease maximum von Mi ses Stress

International Nuclear Information System (INIS)

Pourjamali, H.; Najarian, S.; Katoozian, H. R.

2001-01-01

Hip replacement is used for inoperable femur head injuries and femur fractures where internal fixation can not be used. This operation is one of the most common orthopedic operations that many research have been done about it. Among these we can mention implant and cement materials and composites optimization and also implant shape optimization. This study was designed to optimize artificial hip joint position (placement) to decrease maximal von mi sees stress. First, a model of femur and implant were made and then a computer program was written with the ability to change the position of implant through an acceptable range in the femur. In each of these positions, the program simulated femur and implant according to finite element method and made, applied forces were weight and muscle traction. Our findings show that a small deviation of the implant from femur bone center causes a considerable decrease in von mi sees stress that consequently results in longer maintenance of the implant

Long-term hearing result using Kurz titanium ossicular implants.

Science.gov (United States)

Hess-Erga, Jeanette; Møller, Per; Vassbotn, Flemming Slinning

2013-05-01

Titanium implants in middle ear surgery were introduced in the late 90s and are now frequently used in middle ear surgery. However, long-term studies of patient outcome are few and have only been published in subgroups of patients. We report the long-term effect of titanium middle ear implants for ossicular reconstruction in chronic ear disease investigated in a Norwegian tertiary otological referral centre. Retrospective chart reviews were performed for procedures involving 76 titanium implants between 2000 and 2007. All patients who underwent surgery using the Kurz Vario titanium implant were included in the study. Audiological parameters using four frequencies, 0.5, 1, 2, and 3 kHz, according to AAO-HNS guidelines, was assessed pre and postoperatively. Otosurgical procedures, complications, revisions, and extrusion rates were analyzed. The study had no dropouts. The partial ossicular replacement prosthesis (PORP) was used in 44 procedures and the total ossicular replacement prosthesis (TORP) in 32 procedures, respectively. Mean follow-up was 5.2 years (62 months). The ossiculoplasties were performed as staging procedures or in combination with other chronic ear surgery. The same surgeon performed all the procedures. A postoperative air-bone gap of ≤ 20 dB was obtained in 74 % of the patients, 82 % for the Bell (PORP) prosthesis, and 63 % for the Arial (TORP) prosthesis. The extrusion rate was 5 %. We conclude that titanium ossicular implants give stable and excellent long-term hearing results.

Exhausted implanted pulse generator in sacral nerve stimulation for faecal incontinence: What next in daily practice for patients?

Science.gov (United States)

Duchalais, Emilie; Meurette, Guillaume; Perrot, Bastien; Wyart, Vincent; Kubis, Caroline; Lehur, Paul-Antoine

2016-02-01

The efficacy of sacral nerve stimulation in faecal incontinence relies on an implanted pulse generator known to have a limited lifespan. The long-term use of sacral nerve stimulation raises concerns about the true lifespan of generators. The aim of the study was to assess the lifespan of sacral nerve stimulation implanted pulse generators in daily practice, and the outcome of exhausted generator replacement, in faecal incontinent patients. Faecal incontinent patients with pulse generators (Medtronic Interstim™ or InterstimII™) implanted in a single centre from 2001 to 2014 were prospectively followed up. Generator lifespan was measured according to the Kaplan-Meier method. Patients with a generator explanted/turned off before exhaustion were excluded. Morbidity of exhausted generator replacement and the outcome (Cleveland Clinic Florida Faecal Incontinence (CCF-FI) and Faecal Incontinence Quality of Life (FIQL) scores) were recorded. Of 135 patients with an implanted pulse generator, 112 (InterstimII 66) were included. Mean follow-up was 4.9 ± 2.8 years. The generator reached exhaustion in 29 (26%) cases. Overall median lifespan of an implanted pulse generator was approximately 9 years (95% CI 8-9.2). Interstim and InterstimII 25th percentile lifespan was 7.2 (CI 6.4-8.3) and 5 (CI 4-not reached) years, respectively. After exhaustion, generators were replaced, left in place or explanted in 23, 2 and 4 patients, respectively. Generator replacement was virtually uneventful. CCF-FI/FIQL scores remained unchanged after generator replacement (CCF-FI 8 ± 2 vs 7 ± 3; FIQL 3 ± 0.6 vs 3 ± 0.5; p = ns). In this study, the implanted pulse generator observed median lifespan was 9 years. After exhaustion, generators were safely and efficiently replaced. The study also gives insight into long-term needs and costs of sacral nerve stimulation (SNS) therapy.

Comparing contemporary revision burden among hip and knee joint replacement registries

Directory of Open Access Journals (Sweden)

Brian J. McGrory, MD, MS

2016-06-01

Conclusions: Revision burden has gradually decreased for hip replacements and has remained relatively constant for knee replacements both for the last 4 years and compared to historic controls. Knee revision burden was lower than hip revision burden for each period examined. Revision burden is one measure that may be helpful in following the effect of changes in surgical technique and implant design over time in registry populations and may be a helpful way to compare overall results between registries.

Biomaterials approaches to treating implant-associated osteomyelitis.

Science.gov (United States)

Inzana, Jason A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

2016-03-01

Orthopaedic devices are the most common surgical devices associated with implant-related infections and Staphylococcus aureus (S. aureus) is the most common causative pathogen in chronic bone infections (osteomyelitis). Treatment of these chronic bone infections often involves combinations of antibiotics given systemically and locally to the affected site via a biomaterial spacer. The gold standard biomaterial for local antibiotic delivery against osteomyelitis, poly(methyl methacrylate) (PMMA) bone cement, bears many limitations. Such shortcomings include limited antibiotic release, incompatibility with many antimicrobial agents, and the need for follow-up surgeries to remove the non-biodegradable cement before surgical reconstruction of the lost bone. Therefore, extensive research pursuits are targeting alternative, biodegradable materials to replace PMMA in osteomyelitis applications. Herein, we provide an overview of the primary clinical treatment strategies and emerging biodegradable materials that may be employed for management of implant-related osteomyelitis. We performed a systematic review of experimental biomaterials systems that have been evaluated for treating established S. aureus osteomyelitis in an animal model. Many experimental biomaterials were not decisively more efficacious for infection management than PMMA when delivering the same antibiotic. However, alternative biomaterials have reduced the number of follow-up surgeries, enhanced the antimicrobial efficacy by delivering agents that are incompatible with PMMA, and regenerated bone in an infected defect. Understanding the advantages, limitations, and potential for clinical translation of each biomaterial, along with the conditions under which it was evaluated (e.g. animal model), is critical for surgeons and researchers to navigate the plethora of options for local antibiotic delivery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antibacterial Envelope Is Associated With Low Infection Rates After Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Device Replacement: Results of the Citadel and Centurion Studies.

Science.gov (United States)

Henrikson, Charles A; Sohail, M Rizwan; Acosta, Helbert; Johnson, Eric E; Rosenthal, Lawrence; Pachulski, Roman; Dan, Dan; Paladino, Walter; Khairallah, Farhat S; Gleed, Kent; Hanna, Ibrahim; Cheng, Alan; Lexcen, Daniel R; Simons, Grant R

2017-10-01

This study sought to determine whether the nonabsorbable TYRX Antibacterial Envelope (TYRX) reduces major cardiovascular implantable electronic device (CIED) infections 12 months after implant. TYRX is a monofilament polypropylene mesh impregnated with minocycline and rifampin specifically designed to hold a CIED in place and elute antimicrobials over time. There are limited data on its ability to reduce CIED infections. We prospectively enrolled patients who underwent generator replacement with an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy device (CRT), treated with TYRX. The primary endpoints were major CIED infection and CIED mechanical complications. Given the differences in infection rates among ICD and CRT patients, 3 different control populations were used: a published benchmark rate for ICD patients, and both site-matched and comorbidity-matched controls groups for CRT patients. Overall, a major CIED infection occurred in 5 of 1,129 patients treated with TYRX (0.4%; 95% confidence interval: 0.0% to 0.9%), significantly lower than the 12-month benchmark rate of 2.2% (p = 0.0023). Among the TYRX-treated CRT cohort, the major CIED infection rate was 0.7% compared with an infection rate of 1.0% and 1.3% (p = 0.38 and p = 0.02) in site-matched and comorbidity-matched control groups, respectively. Among the ICD group, the 12-month infection rate was 0.2% compared with the published benchmark of 2.2% (p = 0.0052). The most common CIED mechanical complication in study patients was pocket hematoma, which occurred in 18 of the 1,129 patients (1.6%; 95% confidence interval: 0.8 to 2.5), which is comparable with a published rate of 1.6%. Use of TYRX was associated with a lower major CIED infection rate. (TYRX™ Envelope for Prevention of Infection Following Replacement With a CRT or ICD; [Centurion]; NCT01043861/NCT01043705). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights

Systemic antibiotics and the risk of superinfection in peri-implantitis.

Science.gov (United States)

Verdugo, Fernando; Laksmana, Theresia; Uribarri, Agurne

2016-04-01

Peri-implantitis has emerged in the last few years as a complication difficult to resolve. The etiopathogenesis consensus is mainly attributed to bacteria. Following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines, a PubMed/Medline literature search was performed using the US National Library of Medicine database up to 2015 to analyze available scientific data on the rationale and risk of superinfection associated to systemic antimicrobials in human peri-implant disease. A hand search was also conducted on relevant medical and microbiology journals. The methodological index for non-randomized studies (MINORS) was independently assessed for quality on the selected papers. Proposed combined therapies use broad-spectrum antibiotics to halt the disease progression. A major associated risk, particularly when prescribed empirically without microbiological follow-up, is the undetected development of superinfections and overgrowth of opportunistic pathogens difficult to eradicate. Peri-implant superinfections with opportunistic bacteria, yeast and viruses, are plausible risks associated to the use of systemic antibiotics in immunocompetent individuals. Lack of microbiological follow-up and antibiotic susceptibility testing may lead to ongoing microbial challenges that exacerbate the disease progression. The increased proliferation of antimicrobial resistance, modern implant surface topography and indiscriminative empiric antibiotic regimens may promote the escalation of peri-implant disease in years to come. A personalized 3-month supportive therapy may help prevent risks by sustaining a normal ecological balance, decreasing specific pathogen proportions and maintaining ideal plaque control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Infective endocarditis following Melody valve implantation: comparison with a surgical cohort.

Science.gov (United States)

O'Donnell, Clare; Holloway, Rhonda; Tilton, Elizabeth; Stirling, John; Finucane, Kirsten; Wilson, Nigel

2017-03-01

Infective endocarditis has been reported post Melody percutaneous pulmonary valve implant; the incidence and risk factors, however, remain poorly defined. We identified four cases of endocarditis from our first 25 Melody implants. Our aim was to examine these cases in the context of postulated risk factors and directly compare endocarditis rates with local surgical valves. We conducted a retrospective review of patients post Melody percutaneous pulmonary valve implant in New Zealand (October, 2009-May, 2015) and also reviewed the incidence of endocarditis in New Zealand among patients who have undergone surgical pulmonary valve implants. In total, 25 patients underwent Melody implantation at a median age of 18 years. At a median follow-up of 2.9 years, most were well with low valve gradient (median 27 mmHg) and only mild regurgitation. Two patients presented with life-threatening endocarditis and obstructive vegetations at 14 and 26 months post implant, respectively. Two additional patients presented with subacute endocarditis at 5.5 years post implant. From 2009 to May, 2015, 178 surgical pulmonic bioprostheses, largely Hancock valves and homografts, were used at our institution. At a median follow-up of 2.9 years, four patients (2%) had developed endocarditis in this group compared with 4/25 (16%) in the Melody group (p=0.0089). Three surgical valves have been replaced. The Melody valve offers a good alternative to surgical conduit replacement in selected patients. Many patients have excellent outcomes in the medium term. Endocarditis, however, can occur and if associated with obstruction can be life threatening. The risk for endocarditis in the Melody group was higher in comparison with that in a contemporaneous surgical pulmonary implant cohort.

Thin hydroxyapatite surface layers on titanium produced by ion implantation

CERN Document Server

Baumann, H; Bilger, G; Jones, D; Symietz, I

2002-01-01

In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha,alpha) backscattering and the resonant nuclear reaction sup 1 H( sup 1 sup 5 N,alpha gamma) sup 1 sup 2 C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of m...

Piezoelectric ceramic implants: in vivo results.

Science.gov (United States)

Park, J B; Kelly, B J; Kenner, G H; von Recum, A F; Grether, M F; Coffeen, W W

1981-01-01

The suitability of barium titanate (BaTiO3) ceramic for direct substitution of hard tissues was evaluated using both electrically stimulated (piezoelectric) and inactive (nonpolarized) test implants. Textured cylindrical specimens, half of them made piezoelectric by polarization in a high electric field, were implanted into the cortex of the midshaft region of the femora of dogs for various periods of time. Interfacial healing and bio-compatibility of the implant material were studied using mechanical, microradiographical, and histological techniques. Our results indicate that barium titanate ceramic shows a very high degree of biocompatibility as evidenced by the absence of inflammatory or foreign body reactions at the implant-tissue interface. Furthermore, the material and its surface porosity allowed a high degree of bone ingrowth as evidenced by microradiography and a high degree of interfacial tensile strength. No difference was found between the piezoelectric and the electrically neutral implant-tissue interfaces. Possible reasons for this are discussed. The excellent mechanical properties of barium titanate, its superior biocompatibility, and the ability of bone to form a strong mechanical interfacial bond with it, makes this material a new candidate for further tests for hard tissue replacement.

Personalized hip implants manufacturing and testing

Science.gov (United States)

Croitoru, A. Sorin Mihai; Pacioga, B. Adrian; Comsa, C. Stanca

2017-09-01

Two models of Ti6Al4V personalized femoral stems for hip replacement have been designed and laser sintered with different sizes of fenestrated architecture that mimics the natural structure of bone, ensuring postoperative bone ingrowth and increasing the elasticity of the entire structure. They were tested statically and dynamically versus a commercial femoral stem. Mechanical tests were performed in order to determine the fatigue limit using the Locati method. The tests were conducted in a thermostatic bath (37°±1°) with the implants immersed in distilled water salted solution 0.91%. For probe embedment poly-methyl methacrylate (PMMA) was used. The characteristic curves of the two personalized fenestrated implants reveal an elastic behaviour by their nonlinear appearance. After dynamic tests an inverse relationship between displacements obtained in the static tests and the fatigue limit was observed. Large fenestrations conferred the desired elasticity to the implant, but contributed to a life service reduction. The fatigue limit for both implants was much above the minimum value specified by ISO 7602: 2010, so both models can be safely used in the medical practice, leading to increased life service of implants.

Modular endoprosthetic replacement for metastatic tumours of the proximal femur

Directory of Open Access Journals (Sweden)

Carter Simon R

2008-11-01

Full Text Available Abstract Background and aims Endoprosthetic replacements of the proximal femur are commonly required to treat destructive metastases with either impending or actual pathological fractures at this site. Modular prostheses provide an off the shelf availability and can be adapted to most reconstructive situations for proximal femoral replacements. The aim of this study was to assess the clinical and functional outcomes following modular tumour prosthesis reconstruction of the proximal femur in 100 consecutive patients with metastatic tumours and to compare them with the published results of patients with modular and custom made endoprosthetic replacements. Methods 100 consecutive patients who underwent modular tumour prosthetic reconstruction of the proximal femur for metastases using the METS system from 2001 to 2007 were studied. The patient, tumour and treatment factors in relation to overall survival, local control, implant survival and complications were analysed. Functional scores were obtained from surviving patients. Results and conclusion There were 45 male and 55 female patients. The mean age was 60.2 years. The indications were metastases. Seventy five patients presented with pathological fracture or with failed fixation and 25 patients were at a high risk of developing a fracture. The mean follow up was 15.9 months [range 0–77]. Three patients died within 2 weeks following surgery. 69 patients have died and 31 are alive. Of the 69 patients who were dead 68 did not need revision surgery indicating that the implant provided single definitive treatment which outlived the patient. There were three dislocations (2/5 with THR and 1/95 with unipolar femoral heads. 6 patients had deep infections. The estimated five year implant survival (Kaplan-Meier analysis was 83.1% with revision as end point. The mean TESS score was 64% (54%–82%. We conclude that METS modular tumour prosthesis for proximal femur provides versatility; low implant related

Evaluation of porous vitreous carbon or silicon implants by radiology in rat's skull; Avaliacao radiologica de implantes de carbono vitreo poroso ou silicone em cranio de ratos

Energy Technology Data Exchange (ETDEWEB)

Vaccari-Mazzetti, Marcelo Paulo; Kobata, Celio Toshiro [Lusiada University of Santos, SP (Brazil). Hospital Defeitos da Face. Dept. of Surgery]. E-mail: mmgvaccari@ig.com.br; Fabiani, Paulo [Lusiada University of Santos, SP (Brazil). Dept. of Radiology; Martins, Dulce Maria Fonseca Soares [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Surgery. Div. of Plastic Surgery; Gomes, Paulo de Oliveira [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Surgery. Div. of Operatory Technique and Experimental Surgery; Martins, Jose Luiz [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Surgery. Div. of Pediatric Surgery

2008-07-01

Purpose: Evaluate by CT the use of porous vitreous carbon (PVC) and silicon (S) implants as the replacement bone in the craniofacial skeleton of rats. Methods: 40 rats divided in: Group A (n=20) PVC submitted to the implant of a fragment in skull. After the euthanasia, the animals were divided into two subgroups: A I: 10 animals, studied in the 7th postoperative day (P.O) and AII: 10 animals, studied in the 28th P.O. In group B, S, 20 rats were submitted to S implant in the skull. All other steps were identical to group A, with designation of subgroups BI and BII. CT with beams in axial cuts of 1 mm thickness to obtain 3-D information It was used Hounsfield scale for evaluate the radio density of the implant. They were used non parametric tests to analyze the results. Results: The 7th PO boss remained in the two groups, but for 28th PO, observed reduction in the volume of the implant in Group A, not observed in group B. CT studies noticed different radio densities around all of S prostheses (pseudo capsule), that do not appeared in CPV implants. The S has remained unchanged in the CT, but the CPV has had a modification in its radio density (p{<=}0,05), in all implants. Conclusion: In CT evaluation the implants of CPV have greater deformation that the S, which makes them not suitable for replacement of membranous bone in the rat skull. (author)

Minimally Invasive Epicardial Pacemaker Implantation in Neonates with Congenital Heart Block.

Science.gov (United States)

Costa, Roberto; Silva, Katia Regina da; Martinelli Filho, Martino; Carrillo, Roger

2017-10-01

Few studies have characterized the surgical outcomes following epicardial pacemaker implantation in neonates with congenital complete atrioventricular block (CCAVB). This study sought to assess the long-term outcomes of a minimally invasive epicardial approach using a subxiphoid access for pacemaker implantation in neonates. Between July 2002 and February 2015, 16 consecutive neonates underwent epicardial pacemaker implantation due to CCAVB. Among these, 12 (75.0%) had congenital heart defects associated with CCAVB. The patients had a mean age of 4.7 ± 5.3 days and nine (56.3%) were female. Bipolar steroid-eluting epicardial leads were implanted in all patients through a minimally invasive subxiphoid approach and fixed on the diaphragmatic ventricular surface. The pulse generator was placed in an epigastric submuscular position. All procedures were successful, with no perioperative complications or early deaths. Mean operating time was 90.2 ± 16.8 minutes. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 4.1 ± 3.9 years. Three children underwent pulse generator replacement due to normal battery depletion at 4.0, 7.2, and 9.0 years of age without the need of ventricular lead replacement. There were two deaths at 12 and 325 days after pacemaker implantation due to bleeding from thrombolytic use and progressive refractory heart failure, respectively. Epicardial pacemaker implantation through a subxiphoid approach in neonates with CCAVB is technically feasible and associated with excellent surgical outcomes and pacing lead longevity.

Formation of planar waveguides in bismuth germanate by 4He+ ion implantation

International Nuclear Information System (INIS)

Mahdavi, S.M.; Chandler, P.J.; Townsend, P.D.

1989-01-01

Planar optical waveguides have been formed in crystalline bismuth germanate (BGO) Bi 4 Ge 3 O 12 , by He + ion implantation. The refractive index profiles have been determined using a dark-mode technique at 0.6328 and 0.488 micrometres. In the region of the electronic and nuclear stopping power of the ion beam in bismuth germanate there is an index enhancement, which forms an optical 'well', This is stable up to ∼ 200 0 C, but then there is a gradual recovery of index up to 400 0 C. Between 425 and 450 0 C, for heavily implanted samples (≥4 x 10 16 ions/cm 2 ), the well rapidly disappears, and is replaced by a sharp 'barrier' of reduced index. For lower dose implants ( 16 ion/cm 2 ) at 450 0 C many of the modes disappear without being replaced by a sharp barrier. (author)

Meniscus tear surgery and meniscus replacement

Science.gov (United States)

Vaquero, Javier; Forriol, Francisco

2016-01-01

Summary Objective the menisci are easily injured and difficult to repair. The aim of this study was to analyze the current state of meniscal surgery aimed at preserving morphology and conserving the biomechanics of the knee to prevent joint degeneration. Methodology a search of the electronic medical literature database Medline was conducted, from http://www.ncbi.nlm.nih.gov/pubmed. The search was not limited by language. Candidate articles were identified by searching for those that included the keywords meniscus, surgery, suture, implant, allograft. The limits were included for clinical research and clinical trials. Basic research was not included. The studies selected were evaluated and classified in three different categories: basic science, reconstruction (suture and meniscectomy) and implants (scaffolds and allograft). Results the consequences of meniscectomy performed at a young age can lead to a joint cartilage degeneration twenty years later. There are few surgical options for the repair of meniscal injuries in order both to preserve the meniscus and to ensure the long term survival of the knee joint, meniscectomy, repair, suturing the tear, or reconstruction, when a meniscal allograft or synthetic substitute is used to replace the meniscus, but the biomechanical properties of the native meniscus are not reproduced entirely by the scaffolds that exist today. Conclusion therapies that successfully repair or replace the meniscus are therefore likely to prevent or delay osteoarthritis progression. PMID:27331034

Combination of natural teeth and osseointegrated implants as prosthesis abutments in a posterior cantilever bridge

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Michael Josef Kridanto Kamadjaja

2008-06-01

Full Text Available Dental implants have been used for several decades. Patients of all ages have chosen dental implants to replace a single tooth or several teeth or to support partial or full dentures. This paper reports two cases of patients treated with dental implant as alternative to replace the missing teeth and connected with natural tooth as abutments in a fixed restoration with distal cantilever bridge. The underlining reasons that we decided to make such kind fixed prostheses are because of clinically imposible to put the implant on certain area and the patients asked for prostheses as optimum as possible, so the mastication function could return to the homeostasis condition. The benefit of these treatments are that prostheses could be made as optimum as possible with a more economic price, so the patients feel quite satisfied. The result shows that a few years after the treatments finished there is no any disadvantageous effect of connecting teeth to implants as abutments in fixed partial dentures and there is no sign of a harmful effect to the opposing teeth either.

Effects of repeated manual disassembly and reassembly on the position stability of various implant-abutment complexes

OpenAIRE

Semper, Wiebke

2010-01-01

In this experiment the precision of manually repositioned abutments in five implant systems with various implant-abutment interfaces was evaluated. Material und Method Of these five implant systems (Straumann, Astra Tech, Replace Select, Camlog, SteriOss) six angled (0°, 5°, 15°) implants each were fixated in a prefabricated metal block. Three persons with differing experience and knowledge of the hypothesis placed and removed a prefabricated abutment with anti-rotational features ...

Therapeutic interaction of systemically-administered mesenchymal stem cells with peri-implant mucosa.

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Ryosuke Kondo

Full Text Available OBJECTIVES: The objective of this study was to investigate the effect of systemically transplanted mesenchymal stem cells (MSCs on the peri-implant epithelial sealing around dental implants. MATERIALS AND METHODS: MSCs were isolated from bone marrow of donor rats and expanded in culture. After recipient rats received experimental titanium dental implants in the bone sockets after extraction of maxillary right first molars, donor rat MSCs were intravenously transplanted into the recipient rats. RESULTS: The injected MSCs were found in the oral mucosa surrounding the dental implants at 24 hours post-transplantation. MSC transplantation accelerated the formation of the peri-implant epithelium (PIE-mediated mucosa sealing around the implants at an early stage after implantation. Subsequently, enhanced deposition of laminin-332 was found along the PIE-implant interface at 4 weeks after the replacement. We also observed enhanced attachment and proliferation of oral mucous epithelial cells. CONCLUSION: Systemically transplanted MSCs might play a critical role in reinforcing the epithelial sealing around dental implants.

Synthesis of metastable A-15 ''Nb3Si'' by ion implantation and on its superconducting transition temperature

International Nuclear Information System (INIS)

Clapp, M.T.; Rose, R.M.

1980-01-01

The authors have found a new technique for the synthesis of metastable compounds of well-defined composition: namely, ion implantation of a selected element into the desired crystal structure. [M.T. Clapp and R.M. Rose, Appl. Phys. Lett. 33, 205 (1978)]. Starting with a substrate material of A-15 Nb 3 Al/sub 0.9/Si/sub 0.1/, two basic approaches were tried towards the formation of A-15 Nb 3 Si by Si implantation: (1) direct replacement of the Al by Si and (2) implantation into a surface layer depleted of Al. This latter approach proved to be the most successful. It consisted of removing the Al by a diffusion anneal and replacing the Al deficiency by sequential Si implantations. Upon subsequent heat treatment a surface layer of A-15 Nb 3 Al/sub 0.2/Si/sub 0.8/ was produced. Details of the experimental procedure and a discussion of the superconducting transition temperature measurements of the implanted surfaces are presented

Evaluation of porous vitreous carbon or silicon implants by radiology in rat's skull

International Nuclear Information System (INIS)

Vaccari-Mazzetti, Marcelo Paulo; Kobata, Celio Toshiro; Fabiani, Paulo; Martins, Dulce Maria Fonseca Soares; Gomes, Paulo de Oliveira; Martins, Jose Luiz

2008-01-01

Purpose: Evaluate by CT the use of porous vitreous carbon (PVC) and silicon (S) implants as the replacement bone in the craniofacial skeleton of rats. Methods: 40 rats divided in: Group A (n=20) PVC submitted to the implant of a fragment in skull. After the euthanasia, the animals were divided into two subgroups: A I: 10 animals, studied in the 7th postoperative day (P.O) and AII: 10 animals, studied in the 28th P.O. In group B, S, 20 rats were submitted to S implant in the skull. All other steps were identical to group A, with designation of subgroups BI and BII. CT with beams in axial cuts of 1 mm thickness to obtain 3-D information It was used Hounsfield scale for evaluate the radio density of the implant. They were used non parametric tests to analyze the results. Results: The 7th PO boss remained in the two groups, but for 28th PO, observed reduction in the volume of the implant in Group A, not observed in group B. CT studies noticed different radio densities around all of S prostheses (pseudo capsule), that do not appeared in CPV implants. The S has remained unchanged in the CT, but the CPV has had a modification in its radio density (p≤0,05), in all implants. Conclusion: In CT evaluation the implants of CPV have greater deformation that the S, which makes them not suitable for replacement of membranous bone in the rat skull. (author)

Infection after pacemaker implantation: infection rates and risk factors associated with infection in a population-based cohort study of 46299 consecutive patients

Science.gov (United States)

Johansen, Jens Brock; Jørgensen, Ole Dan; Møller, Mogens; Arnsbo, Per; Mortensen, Peter Thomas; Nielsen, Jens Cosedis

2011-01-01

Aims Infection is a serious complication of pacemaker (PM) systems. Although the rate of infection has been debated, the figures are largely unknown. We therefore studied the incidence of PM infection and its associated risk factors in the Danish population. Methods and results Since 1982, all PM implantation and removal procedures performed in Denmark have been prospectively recorded in the Danish Pacemaker Register. All patients (n = 46299) who underwent implantation between 1982 and 2007 were included. The total length of surveillance was 236 888 PM-years. The incidence of infection was calculated according to the total number of PM-years. The incidence of surgical site infection (≤365 days after PM implantation) was compared with later infection in first implant and replacement procedures. Multiple-record and multiple-event-per-subject proportional hazards analyses were used to identify the independent risk factors of PM infection. Surgical site infection occurred in 192 cases after first implantation (incidence rate 4.82/1000 PM-years), and in 133 cases after replacement (12.12/1000 PM-years). Infections occurring more than 365 days after the first implantation occurred in 153 cases (1.02/1000 PM-years), and in 118 cases after replacement (3.26/1000 PM-years). Independent factors associated with an increased risk of PM infection were a greater number of PM operations (including replacements), male sex, younger age, implantation during the earliest part of the study period, and absence of antibiotics (P< 0.001). Conclusion The overall risk of infection after PM implantation was low. A greater number of operations augmented the risk of infection. This should be taken into account when considering revisions of PM systems. PMID:21252172

Angulated Dental Implants in Posterior Maxilla FEA and Experimental Verification

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Hamed A. Hamed

2018-02-01

Full Text Available AIM: This study aimed to evaluate the effect of different implant angulations in posterior maxilla on stress distribution by finite element analysis and verify its results experimentally. METHODS: Two simplified models were prepared for an implant placed vertically and tilted 25° piercing the maxillary sinus. Geometric models' components were prepared by Autodesk Inventor then assembled in ANSYS for finite element analysis. The results of finite element analysis were verified against experimental trials results which were statistically analysed using student t-test (level of significance p < 0.05. RESULTS: Implant - abutment complex absorbed the load energy in case of vertical implant better than the case of angulated one. That was reflected on cortical bone stress, while both cases showed stress levels within the physiological limits. Comparing results between FEA and experiment trials showed full agreement. CONCLUSION: It was found that the tilted implant by 25° can be utilised in the posterior region maxilla for replacing maxillary first molar avoiding sinus penetration. The implant-bone interface and peri-implant bones received the highest Von Mises stress. Implant - bone interface with angulated implant received about 66% more stresses than the straight one.

Angulated Dental Implants in Posterior Maxilla FEA and Experimental Verification.

Science.gov (United States)

Hamed, Hamed A; Marzook, Hamdy A; Ghoneem, Nahed E; El-Anwar, Mohamed I

2018-02-15

This study aimed to evaluate the effect of different implant angulations in posterior maxilla on stress distribution by finite element analysis and verify its results experimentally. Two simplified models were prepared for an implant placed vertically and tilted 25° piercing the maxillary sinus. Geometric models' components were prepared by Autodesk Inventor then assembled in ANSYS for finite element analysis. The results of finite element analysis were verified against experimental trials results which were statistically analysed using student t-test (level of significance p < 0.05). Implant - abutment complex absorbed the load energy in case of vertical implant better than the case of angulated one. That was reflected on cortical bone stress, while both cases showed stress levels within the physiological limits. Comparing results between FEA and experiment trials showed full agreement. It was found that the tilted implant by 25° can be utilised in the posterior region maxilla for replacing maxillary first molar avoiding sinus penetration. The implant-bone interface and peri-implant bones received the highest Von Mises stress. Implant - bone interface with angulated implant received about 66% more stresses than the straight one.

Antimicrobial and Antifouling Polymeric Agents for Surface Functionalization of Medical Implants.

Science.gov (United States)

Zeng, Qiang; Zhu, Yiwen; Yu, Bingran; Sun, Yujie; Ding, Xiaokang; Xu, Chen; Wu, Yu-Wei; Tang, Zhihui; Xu, Fu-Jian

2018-05-09

Combating implant-associated infections is an urgent demand due to the increasing numbers in surgical operations such as joint replacements and dental implantations. Surface functionalization of implantable medical devices with polymeric antimicrobial and antifouling agents is an efficient strategy to prevent bacterial fouling and associated infections. In this work, antimicrobial and antifouling branched polymeric agents (GPEG and GEG) were synthesized via ring-opening reaction involving gentamicin and ethylene glycol species. Due to their rich primary amine groups, they can be readily coated on the polydopamine-modified implant (such as titanium) surfaces. The resultant surface coatings of Ti-GPEG and Ti-GEG produce excellent in vitro antibacterial efficacy toward both Staphylococcus aureus and Escherichia coli, while Ti-GPEG exhibit better antifouling ability. Moreover, the infection model with S. aureus shows that implanted Ti-GPEG possessed excellent antibacterial and antifouling ability in vivo. This study would provide a promising strategy for the surface functionalization of implantable medical devices to prevent implant-associated infections.

Terminal Posterior Tilted Implants Planned as a Sinus Graft Alternative for Fixed Full-Arch Implant-Supported Maxillary Restoration: A Case Series with 10- to 19-Year Results on 44 Consecutive Patients Presenting for Routine Maintenance.

Science.gov (United States)

Fortin, Yvan; Sullivan, Richard M

2017-02-01

Posterior maxillary tilted implants are gaining prevalence as an alternative to sinus grafts supporting fixed maxillary restorations. This paper reports long-term results after loading using this technique. Consecutive patients presenting for either routine hygiene maintenance or unplanned emergency care who had received tilted implants as a sinus graft alternative to support fixed fully implant-supported restoration of an edentulous maxilla and were followed for a minimum of 10 years from initial implant placement were included in this evaluation. Forty-four patients were identified: 40 with bilateral tilted implants and 4 with one tilted and one axial posterior implant. Eight patients received one-piece fixed porcelain-to-gold screw-retained restorations, and thirty-six patients received a fully implant-supported patient-removable Marius Bridge. Seventy-nine out of 84 originally loaded posterior tilted implants survived a minimum of 10 years loading; one tilted implant was lost at 10 years. Eight additional posterior implants were placed for either these lost tilted posterior implants or as proactive supplemental support; one of these replacement tilted implants survived for at least 10 years and is included in the data. All patients have maintained continuous fixed function throughout the follow-up period. Forty-one out of 44 patients continue with the original restoration, 33 without modification or removal of the fixed restoration or implant-connecting bar. One porcelain-to-gold and seven Marius Bridges had framework modifications to accommodate additional implants; 3 Marius Bridge restorations were replaced with a newer generation. Within the limits of this retrospective study, the results show that continuous fixed function of fully implant-supported maxillary restorations using posterior tilted implants in terminal positions of support as a sinus graft alternative combined with axial anterior implants is possible over a prolonged period. Loss of a posterior

Bicruciate-retaining Total Knee Replacement Provides Satisfactory Function and Implant Survivorship at 23 Years.

Science.gov (United States)

Pritchett, James W

2015-07-01

One of the goals of a TKA is to approximate the function of a normal knee. Preserving the natural ligaments might provide a method of restoring close to normal function. Sacrifice of the ACL is common and practical during a TKA. However, this ligament is functional in more than 60% of patients undergoing a TKA and kinematic studies support the concept of bicruciate-retaining (that is, ACL-preserving) TKA; however, relatively few studies have evaluated patients treated with bicruciate-retaining TKA implants. I asked: (1) what is the long-term (minimum 20-year) survivorship, (2) what are the functional results, and (3) what are the reasons for revision of bicruciate-retaining knee arthroplasty prostheses? From January 1989 to September 1992, I performed 639 total knee replacements in 537 patients. Of these, 489 were performed in 390 patients using a bicruciate-retaining, minimally constrained device. During the period in question, this knee prosthesis was used for all patients observed intraoperatively to have an intact, functional ACL with between 15° varus and 15° valgus joint deformity. There were 234 women and 156 men with a mean age at surgery of 65 years (range, 42-84 years) and a primary diagnosis of osteoarthritis in 89%. The patella was resurfaced in all knees. The mean followup was 23 years (range, 20-24 years). At the time of this review, 199 (51%) patients had died and 31 (8%) patients were lost to followup, leaving 160 (41%) patients (214 knees) available for review. Component survivorship was determined by competing-risks analysis and Kaplan Meier survivorship analysis with revision for any reason as the primary endpoint. Patients were evaluated every 2 years to assess ROM, joint laxity, knee stability, and to determine American Knee Society scores. The Kaplan-Meier survivorship was 89% (95% CI, 82%-93%) at 23 years with revision for any reason as the endpoint. Competing-risks survivorship was 94% (95% CI, 91%%-96 %) at 23 years. At followup, the mean

Pain-only complaint about cochlear implant device: A five-patient pediatric experience.

Science.gov (United States)

Todd, Norman Wendell; Fainberg, Jolie C; Ukatu, CeIsha Chinwe; Venable, Claudia Y; Segel, Phil

2015-09-01

To present the case histories and management of five pediatric patients who experienced pain at the receiver-stimulator site, but no other indication that the device was failing. Patients were from a sole-surgeon pediatric practice (600 + implant surgeries before June 2013; about even proportions of Advanced Bionics, Cochlear Corporation, and MED-EL devices). The University Institutional Review Board-approved review of sole-surgeon pediatric case series. The onset of pain ranged from 2 to 16 years post implantation. Pain, not amenable to conventional medical therapy, was present regardless of whether or not the external appliance was 'on', or even being worn on the head. Four of the five patients were bilaterally implanted, but pain was only at one receiver-stimulator package. Clinical management ultimately included revision surgery in all five cases, with immediate resolution of the pain in four. For those four, the replacement cochlear implant (CI) performed well; the other patient fears pain if her replacement device is used, but continues enjoying her contralateral implant. At analysis by the company, two of five explanted devices exhibited problems: loss of hermeticity; insulation failure. Though infrequently reported, pain-only complaint by a CI user is a challenging dilemma. Pain may be the sole clinical manifestation of cochlear implant device failure. We offer a flowchart for the care of CI patients with pain, encourage a worldwide registry of such cases, and offer ideas to try to understand better the problem.

Clinical Application of Scaffolds for Partial Meniscus Replacement.

Science.gov (United States)

Moran, Cathal J; Withers, Daniel P; Kurzweil, Peter R; Verdonk, Peter C

2015-09-01

Meniscal tears are common injuries often treated by partial meniscectomy. This may result in altered joint contact mechanics which in turn may lead to worsening symptoms and an increased risk of osteoarthritis. Meniscal scaffolds have been proposed as a treatment option aimed at reducing symptoms while also potentially reducing progression of degenerative change. There are 2 scaffolds available for clinical use at the present time; Collagen Meniscus Implant and Actifit. Medium-term to long-term data (4.9 to 11.3 y) demonstrate efficacy of partial meniscus replacement. The patients who seem to benefit most are chronic postmeniscectomy rather than acute meniscal injuries. Herein we report on available clinical data for Collagen Meniscus Implant and Actifit while describing our preferred surgical technique and postoperative rehabilitation program.

Osseoperception in Dental Implants: A Systematic Review.

Science.gov (United States)

Mishra, Sunil Kumar; Chowdhary, Ramesh; Chrcanovic, Bruno Ramos; Brånemark, Per-Ingvar

2016-04-01

Replacement of lost teeth has significant functional and psychosocial effects. The capability of osseointegrated dental implants to transmit a certain amount of sensibility is still unclear. The phenomenon of developing a certain amount of tactile sensibility through osseointegrated dental implants is called osseoperception. The aim of this article is to evaluate the available literature to find osseoperception associated with dental implants. To identify suitable literature, an electronic search was performed using Medline and PubMed database. Articles published in English and articles whose abstract is available in English were included. The articles included in the review were based on osseoperception, tactile sensation, and neurophysiological mechanoreceptors in relation to dental implants. Articles on peri-implantitis and infection-related sensitivity were not included. Review articles without the original data were excluded, although references to potentially pertinent articles were noted for further follow-up. The phenomenon of osseoperception remains a matter of debate, so the search strategy mainly focused on articles on osseoperception and tactile sensibility of dental implants. This review presents the histological, neurophysiological, and psychophysical evidence of osseoperception and also the role of mechanoreceptors in osseoperception. The literature on osseoperception in dental implants is very scarce. The initial literature search resulted in 90 articles, of which 81 articles that fulfilled the inclusion criteria were included in this systematic review. Patients restored with implant-supported prostheses reported improved tactile and motor function when compared with patients wearing complete dentures. © 2016 by the American College of Prosthodontists.

The Pathology of Orthopedic Implant Failure Is Mediated by Innate Immune System Cytokines

OpenAIRE

Landgraeber, Stefan; Jäger, Marcus; Jacobs, Joshua J.; Hallab, Nadim James

2014-01-01

All of the over 1 million total joint replacements implanted in the US each year are expected to eventually fail after 15–25 years of use, due to slow progressive subtle inflammation at the bone implant interface. This inflammatory disease state is caused by implant debris acting, primarily, on innate immune cells, that is, macrophages. This slow progressive pathological bone loss or “aseptic loosening” is a potentially life-threatening condition due to the serious complications in older peop...

Fixation of revision implants is improved by a surgical technique to crack the sclerotic bone rim.

Science.gov (United States)

Kold, Søren; Bechtold, Joan E; Mouzin, Olivier; Elmengaard, Brian; Chen, Xinqian; Søballe, Kjeld

2005-03-01

Revision joint replacement has poorer outcomes compared with primary joint replacement, and these poor outcomes have been associated with poorer fixation. We investigated a surgical technique done during the revision operation to improve access from the marrow space to the implant interface by locally cracking the sclerotic bone rim that forms during aseptic loosening. Sixteen implants were inserted bilaterally by distal femur articulation of the knee joint of eight dogs, using our controlled experimental model that replicates the revision setting (sclerotic bone rim, dense fibrous tissue, macrophages, elevated cytokines) by pistoning a loaded 6.0-mm implant 500 microm into the distal femur with particulate PE. At 8 weeks, one of two revision procedures was done. Both revision procedures included complete removal of the membrane, scraping, lavaging, and inserting a revision plasma-spray Ti implant. The crack revision procedure also used a splined tool to circumferentially locally perforate the sclerotic bone rim before insertion of an identical revision implant. Superior fixation was achieved with the cracking procedure in this experimental model. Revision implants inserted with the rim cracking procedure had a significantly higher pushout strength (fivefold median increase) and energy to failure (sixfold median increase), compared with the control revision procedure. Additional evaluation is needed of local perforation of sclerotic bone rim as a simple bone-sparing means to improve revision implant fixation and thereby increase revision implant longevity.

Total knee replacement in patients with diffuse villonodular synovitis

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Lucio Flávio Biondi Pinheiro Júnior

Full Text Available ABSTRACT This paper reports a case of diffuse pigmented villonodular synovitis (DPVNS, associated with advanced gonarthrosis, submitted to total knee replacement. The patient had progressive pain and swelling. She had two previous surgeries, firstly arthroscopic , synovectomy and subsequently open synovectomy associated with radiotherapy, with recurrence of the disease. Magnetic resonance imaging revealed diffuse synovitis, advanced arthrosis, and bone cysts. The patient was submitted to a total knee replacement and synovectomy. There was a good postoperative clinical course, with improvement of pain, function, and joint edema on examination. The patient will be followed regarding the possibility of disease recurrence and implant survival.,

Placement of replace select Ti-Unite-coated type implants using a combination of immediate and submerge techniques after tooth extraction

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Coen Pramono D

2006-06-01

Full Text Available The high success rate of immediate implant placement both in the anterior and posterior regions were reported by many authors, therefore applying this techniques can be considered as a safe surgical procedure and minimizing the dental office visit for patient satisfaction. This paper reports the outcome of immediate placement of implants following extraction of anterior maxillary teeth. Combination technique of immediate and submerge implant placements including bone grafting procedure were used. Four implants with TiUnite surface type were placed immediately in two patients with the short-term result indicated that this technique may serve as a simple and safe procedure for immediate implant placement. It was concluded that immediate implant placement technique combined with TiUnite implant surface was successful in treating region directly after tooth extraction therefore this technique can be use as an alternative surgical method for dental implant rehabilitation.

Soft tissue grafting to improve implant esthetics

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Moawia M Kassab

2010-09-01

Full Text Available Moawia M KassabDivision of Periodontics, Marquette University, School of Dentistry, Milwaukee, WI, USAAbstract: Dental implants are becoming the treatment of choice to replace missing teeth, especially if the adjacent teeth are free of restorations. When minimal bone width is present, implant placement becomes a challenge and often resulting in recession and dehiscence around the implant that leads to subsequent gingival recession. To correct such defect, the author turned to soft tissue autografting and allografting to correct a buccal dehiscence around tooth #24 after a malpositioned implant placed by a different surgeon. A 25-year-old woman presented with the chief complaint of gingival recession and exposure of implant threads around tooth #24. The patient received three soft tissue grafting procedures to augment the gingival tissue. The first surgery included a connective tissue graft to increase the width of the keratinized gingival tissue. The second surgery included the use of autografting (connective tissue graft to coronally position the soft tissue and achieve implant coverage. The third and final surgery included the use of allografting material Alloderm to increase and mask the implant from showing through the gingiva. Healing period was uneventful for the patient. After three surgical procedures, it appears that soft tissue grafting has increased the width and height of the gingiva surrounding the implant. The accomplished thickness of gingival tissue appeared to mask the showing of implant threads through the gingival tissue and allowed for achieving the desired esthetic that the patient desired. The aim of the study is to present a clinical case with soft tissue grafting procedures.Keywords: case report, connective tissue, dental implants, allograft, coronally positioned flap

Development and fabrication of patient-specific knee implant using additive manufacturing techniques

Science.gov (United States)

Zammit, Robert; Rochman, Arif

2017-10-01

Total knee replacement is the most effective treatment to relief pain and restore normal function in a diseased knee joint. The aim of this research was to develop a patient-specific knee implant which can be fabricated using additive manufacturing techniques and has reduced wear rates using a highly wear resistant materials. The proposed design was chosen based on implant requirements, such as reduction in wear rates as well as strong fixation. The patient-specific knee implant improves on conventional knee implants by modifying the articulating surfaces and bone-implant interfaces. Moreover, tribological tests of different polymeric wear couples were carried out to determine the optimal materials to use for the articulating surfaces. Finite element analysis was utilized to evaluate the stresses sustained by the proposed design. Finally, the patient-specific knee implant was successfully built using additive manufacturing techniques.

Antibacterial iodine-supported titanium implants.

Science.gov (United States)

Shirai, T; Shimizu, T; Ohtani, K; Zen, Y; Takaya, M; Tsuchiya, H

2011-04-01

Deep infection remains a serious complication in orthopedic implant surgery. In order to reduce the incidence of implant-associated infections, several biomaterial surface treatments have been proposed. This study focused on evaluating the antibacterial activity of iodine-supported titanium (Ti-I(2)) and its impact on post-implant infection, as well as determining the potential suitability of Ti-I(2) as a biomaterial. External fixation pins were used in this experiment as trial implants because of the ease of making the septic models. The antibacterial activity of the metal was measured using a modification of the Japanese Industrial Standards method. Activity was evaluated by exposing the implants to Staphylococcus aureus or Escherichia coli and comparing reaction of pathogens to Ti-I(2) vs. stainless steel and titanium controls. Ti-I(2) clearly inhibited bacterial colonization more than the control metals. In addition, cytocompatibility was assessed by counting the number of colonies that formed on the metals. The three metals showed the same amount of fibroblast colony formation. Japanese white rabbits were used as an in vivo model. Three pins were inserted into both femora of six rabbits for histological analysis. Pin sites were inspected and graded for infection and inflammation. Fewer signs of infection and inflammatory changes were observed in conjunction with the Ti-I(2) pins. Furthermore, osteoconductivity of the implant was evaluated with osteoid formation surface of the pin. Consecutive bone formation was observed around the Ti-I(2) and titanium pins, while little osteoid formation was found around the stainless steel pins. These findings suggest that Ti-I(2) has antimicrobial activity and exhibits cytocompatibility. Therefore, Ti-I(2) substantially reduces the incidence of implant infection and shows particular promise as a biomaterial. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Straightforward Case of Dental Implant in General Dentistry

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Aji P. Tjikman

2013-07-01

Full Text Available Dental implant has become a fast developing and dynamic field in dental practice. It is acknowledged as a predictable treatment modality with high clinical success rates. Conventional fixed prostheses are no longer considered to be the first choice of treatment for replacing a missing tooth. Despite the increasing number of patients requesting dental implant treatments, there are only some clinicians who are offering implant therapy in their daily practice. The International team for Implantology described a straightforward case as a simple case such as implant placements in adquate soft and hard tissue conditions and single-tooth restorations in a non-aesthetic zone. A review of the current literature discussed the implementation of implant dentistry in universities worldwide into their curriculum for both undergraduate and postgraduate programs in general dentistry. The European consensus in implant dentistry education concluded that it is desirable to include the surgical technique for implant placement for straightforward cases into the dental curriculum. The levels and limitations to which the various aspects of implant dentistry and related skills are taught to be determined by the academic community. This review aimed at promoting awareness amongst dental practitioners and institutions in Indonesia of the shifting treatment paradigm in the maangement of a missing tooth. Hence clinicians will be able to include implant dentistry in the treatment planning of their patients and also undertake a significant part in the execution of such treatments.

Multidisciplinary management including periodontics, orthodontics, implants, and prosthetics for an adult.

Science.gov (United States)

Pinho, Teresa; Neves, Manuel; Alves, Célia

2012-08-01

This article describes the complex dental treatment of an adult patient with multiple missing teeth, mild chronic periodontitis, and a malocclusion with a cant of the occlusal plane. After periodontal treatment, titanium implants and a miniscrew were placed to correct the occlusal plane canting with orthodontic treatment. Prosthodontic treatment was completed by using osseointegrated implants to replace the missing teeth. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants

DEFF Research Database (Denmark)

Søballe, Kjeld; Mouzin, Olivier R G; Kidder, Louis A

2003-01-01

We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability...... a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included...

Outcomes of implants and restorations placed in general dental practices: a retrospective study by the Practitioners Engaged in Applied Research and Learning (PEARL) Network.

Science.gov (United States)

Da Silva, John D; Kazimiroff, Julie; Papas, Athena; Curro, Frederick A; Thompson, Van P; Vena, Donald A; Wu, Hongyu; Collie, Damon; Craig, Ronald G

2014-07-01

The authors conducted a study to determine the types, outcomes, risk factors and esthetic assessment of implants and their restorations placed in the general practices of a practice-based research network. All patients who visited network practices three to five years previously and underwent placement of an implant and restoration within the practice were invited to enroll. Practitioner-investigators (P-Is) recorded the status of the implant and restoration, characteristics of the implant site and restoration, presence of peri-implant pathology and an esthetic assessment by the P-I and patient. The P-Is classified implants as failures if the original implant was missing or had been replaced, the implant was mobile or elicited pain on percussion, there was overt clinical or radiographic evidence of pathology or excessive bone loss (> 0.2 millimeter per year after an initial bone loss of 2 mm). They classified restorations as failures if they had been replaced or if there was abutment or restoration fracture. The authors enrolled 922 implants and patients from 87 practices, with a mean (standard deviation) follow-up of 4.2 (0.6) years. Of the 920 implants for which complete data records were available, 64 (7.0 percent) were classified as failures when excessive bone loss was excluded from the analysis. When excessive bone loss was included, 172 implants (18.7 percent) were classified as failures. According to the results of univariate analysis, a history of severe periodontitis, sites with preexisting inflammation or type IV bone, cases of immediate implant placement and placement in the incisor or canine region were associated with implant failure. According to the results of multivariate analysis, sites with preexisting inflammation (odds ratio [OR] = 2.17; 95 percent confidence interval [CI], 1.41-3.34]) or type IV bone (OR = 1.99; 95 percent CI, 1.12-3.55) were associated with a greater risk of implant failure. Of the 908 surviving implants, 20 (2.2 percent) had

[Study on Microbial Diversity of Peri-implantitis Subgingival by High-throughput Sequencing].

Science.gov (United States)

Li, Zhi-jie; Wang, Shao-guo; Li, Yue-hong; Tu, Dong-xiang; Liu, Shi-yun; Nie, Hong-bing; Li, Zhi-qiang; Zhang, Ju-mei

2015-07-01

To study microbial diversity of peri-implantitis subgingival with high-throughput sequencing, and investigate microbiological etiology of peri-implantitis. Subgingival plaques were sampled from the patients with peri-implantitis (D group) and non-peri-implantitis subjects (N group). The microbiological diversity of the subgingival plaques was detected by sequencing V4 region of 16S rRNA with Illumina Miseq platform. The diversity of the community structure was analyzed using Mothur software. A total of 156 507 gene sequences were detected in nine samples and 4 402 operational taxonomic units (OTUs) were found. Selenomonas, Pseudomonas, and Fusobacterium were dominant bacteria in D group, while Fusobacterium, Veillonella and Streptococcus were dominant bacteria in N group. Differences between peri-implantitis and non-peri-implantitis bacterial communities were observed at all phylogenetic levels by LEfSe, which was also found in PcoA test. The occurrence of peri-implantitis is not only related to periodontitis pathogenic microbe, but also related with the changes of oral microbial community structure. Treponema, Herbaspirillum, Butyricimonas and Phaeobacte may be closely related to the occurrence and development of peri-implantitis.

Biomaterial strategies for engineering implants for enhanced osseointegration and bone repair

Science.gov (United States)

Agarwal, Rachit; García, Andrés J.

2015-01-01

Bone tissue has a remarkable ability to regenerate and heal itself. However, large bone defects and complex fractures still present a significant challenge to the medical community. Current treatments center on metal implants for structural and mechanical support and auto- or allo-grafts to substitute long bone defects. Metal implants are associated with several complications such as implant loosening and infections. Bone grafts suffer from donor site morbidity, reduced bioactivity, and risk of pathogen transmission. Surgical implants can be modified to provide vital biological cues, growth factors and cells in order to improve osseointegration and repair of bone defects. Here we review strategies and technologies to engineer metal surfaces to promote osseointegration with the host tissue. We also discuss strategies for modifying implants for cell adhesion and bone growth via integrin signaling and growth factor and cytokine delivery for bone defect repair. PMID:25861724

Ion Implantation in Ge: Structural and electrical investigation of the induced lattice damage & Study of the lattice location of implanted impurities

CERN Document Server

Decoster, Stefan; Wahl, Ulrich

The past two decades, germanium has drawn international attention as one of the most promising materials to replace silicon in semiconductor applications. Due to important advantages with respect to Si, such as the increased electron and hole mobility, Ge is well on its way to become an important material in future high-speed integrated circuits. Although the interest in this elemental group IV semiconductor is increasing rapidly nowadays, the number of publications about this material is still relatively scarce, especially when compared to Si. The most widely used technique to dope semiconductors is ion implantation, due to its good control of the dopant concentration and profile, and the isotopic purity of the implanted species. However, there is a major lack of knowledge of the fundamental properties of ion implantation in Ge, which has triggered the research presented in this thesis. One of the most important and generally unwanted properties of ion implantation is the creation of damage to the crystal la...

The medically compromised patient: Are dental implants a feasible option?

Science.gov (United States)

Vissink, A; Spijkervet, Fkl; Raghoebar, G M

2018-03-01

In healthy subjects, dental implants have evolved to be a common therapy to solve problems related to stability and retention of dentures as well as to replace failing teeth. Although dental implants are applied in medically compromised patients, it is often not well known whether this therapy is also feasible in these patients, whether the risk of implant failure and developing peri-implantitis is increased, and what specific preventive measures, if any, have to be taken when applying dental implants in these patients. Generally speaking, as was the conclusion by the leading review of Diz, Scully, and Sanz on placement of dental implants in medically compromised patients (J Dent, 41, 2013, 195), in a few disorders implant survival may be lower, and the risk of a compromised peri-implant health and its related complications be greater, but the degree of systemic disease control outweighs the nature of the disorder rather than the risk accompanying dental implant treatment. So, as dental implant treatment is accompanied by significant functional benefits and improved oral health-related quality of life, dental implant therapy is a feasible treatment in almost any medically compromised patient when the required preventive measures are taken and follow-up care is at a high level. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.

Immediate implants in extraction sockets with periapical lesions: an illustrated review

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Arthur B. Novaes Jr.

2013-10-01

Full Text Available Aim Immediate implantation has gained great attention since first proposed. Immediate implants in replacement of teeth with periapical lesion is, to date, an issue of discussion. The aim of this study is to perform an illustrated literature review of immediate implants in sockets exhibiting previous periapical lesions.Materials and methods A search on medline/EMBASE database was done for the literature review which is presented together with two case reports illustrating the state of the art of immediate implants on sockets with periapical lesions. Both cases are presented in areas with great aesthetic demands and a periapical lesion of considerable size. The two cases were conducted following strict granulation tissue removal and careful rinsing and pre-operative antibiotics, followed by good primary stability of the dental implant.Results and conclusion Both cases represented successes in aesthetics and function, describing a successful protocol for immediate implant installation in areas exhibiting periapical lesions.

Implantable power generation system utilizing muscle contractions excited by electrical stimulation.

Science.gov (United States)

Sahara, Genta; Hijikata, Wataru; Tomioka, Kota; Shinshi, Tadahiko

2016-06-01

An implantable power generation system driven by muscle contractions for supplying power to active implantable medical devices, such as pacemakers and neurostimulators, is proposed. In this system, a muscle is intentionally contracted by an electrical stimulation in accordance with the demands of the active implantable medical device for electrical power. The proposed system, which comprises a small electromagnetic induction generator, electrodes with an electrical circuit for stimulation and a transmission device to convert the linear motion of the muscle contractions into rotational motion for the magneto rotor, generates electrical energy. In an ex vivo demonstration using the gastrocnemius muscle of a toad, which was 28 mm in length and weighed 1.3 g, the electrical energy generated by the prototype exceeded the energy consumed for electrical stimulation, with the net power being 111 µW. It was demonstrated that the proposed implantable power generation system has the potential to replace implantable batteries for active implantable medical devices. © IMechE 2016.

Treatment of acromegaly by yttrium implantation

Energy Technology Data Exchange (ETDEWEB)

Hibbert, J.; Shaheen, O.H.

1977-01-01

Yttrium implantation is one of the many ways of treating acromegaly. The advantages are the minor nature of the procedure and the fact that pituitary replacement is not as commonly required as after hypophysectomy. Thus in young female patients menstruation may be resumed following treatment and pregnancy has occurred. The procedure is not as free from complications as external irradiation but the response is more satisfactory.

Immediate loading and customized restoration of a single implant in the maxillary esthetic zone : A clinical report

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den Hartog, Laurens; Raghoebar, Gerry M.; Stellingsma, Kees; Meijer, Henny J. A.

2009-01-01

The replacement of a single missing anterior tooth with an implant-supported crown Is a demanding therapy. This report describes a treatment in which an anterior maxillary implant was immediately restored with a provisional restoration. During the provisional phase, an optimal emergence profile was

Heat generated by dental implant drills during osteotomy-a review: heat generated by dental implant drills.

Science.gov (United States)

Mishra, Sunil Kumar; Chowdhary, Ramesh

2014-06-01

Osseointegration is the more stable situation and results in a high success rate of dental implants. Heat generation during rotary cutting is one of the important factors influencing the development of osseointegration. To assess the various factors related to implant drills responsible for heat generation during osteotomy. To identify suitable literature, an electronic search was performed using Medline and Pubmed database. Articles published in between 1960 to February 2013 were searched. The search is focused on heat generated by dental implant drills during osteotomy. Various factors related to implant drill such effect of number of blades; drill design, drill fatigue, drill speed and force applied during osteotomies which were responsible for heat generation were reviewed. Titles and abstracts were screened, and literature that fulfilled the inclusion criteria was selected for a full-text reading. The initial literature search resulted in 299 articles out of which only 70 articles fulfils the inclusion criteria and were included in this systematic review. Many factors related to implant drill responsible for heat generation were found. Successful preparation of an implant cavity with minimal damage to the surrounding bone depends on the avoidance of excessive temperature generation during surgical drilling. The relationship between heat generated and implant drilling osteotomy is multifactorial in nature and its complexity has not been fully studied. Lack of scientific knowledge regarding this issue still exists. Further studies should be conducted to determine the various factors which generate less heat while osteotomy such as ideal ratio of force and speed in vivo, exact time to replace a drill, ideal drill design, irrigation system, drill-bone contact area.

Adventure sports and sexual freedom hip replacement: the tripolar hip.

Science.gov (United States)

Pritchett, James W

2018-01-01

Certain athletic activities and lifestyles require a completely stable and very mobile hip. Total hip replacement with a natural femoral head size and two mobile-bearing surfaces (i.e., a "tripolar" prosthesis) is the most stable prosthesis. Elegant design and wear-resistant bearing surfaces are the keys to long-term implant survivorship. The hypothesis is that a ceramic-coated tripolar prosthesis using highly cross-linked polyethylene can provide full function and complete stability with low wear. This study sought to determine: (1) patient-reported outcomes, (2) functional outcomes, (3) implant survivorship and complications, and (4) postoperative sexual limitations. Between 1998 and 2011, the author performed 160 primary total hip replacements using tripolar prostheses in patients participating in adventure sports and other physically demanding activities. The institutional review board approved this study. The inclusion criteria were patients who needed unrestricted activity and who were not candidates for or did not choose hip resurfacing. Patients were followed every second year and assessed with radiographs, Harris Hip Score, WOMAC, SF-12, and UCLA functional outcome scores. Patients were asked about symptoms of instability and satisfaction with their hip replacement. Patients were asked both preoperatively and 2 years postoperatively four questions about their sexual activity. Mean follow-up was 11 years. At 2 years' postoperatively, 98% of patients reported their satisfaction as excellent or good and 99% were not limited for sexual activity following surgery. Seventy-four percent of patients reported they were recovered within 6 weeks of surgery. There were no dislocations. There were three revision procedures for implant loosening, infection, and periprosthetic fracture, but there were no failures of the tripolar articulation. The mean postoperative UCLA score was the highly athletic score of 8. There were no signs of osteolysis, wear, or metal

Conduction Abnormalities and Pacemaker Implantations After SAPIEN 3 Vs SAPIEN XT Prosthesis Aortic Valve Implantation.

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Husser, Oliver; Kessler, Thorsten; Burgdorf, Christof; Templin, Christian; Pellegrini, Costanza; Schneider, Simon; Kasel, Albert Markus; Kastrati, Adnan; Schunkert, Heribert; Hengstenberg, Christian

2016-02-01

Transcatheter aortic valve implantation is increasingly used in patients with aortic stenosis. Post-procedural intraventricular conduction abnormalities and permanent pacemaker implantations remain a serious concern. Recently, the Edwards SAPIEN 3 prosthesis has replaced the SAPIEN XT. We sought to determine the incidences of new-onset intraventricular conduction abnormalities and permanent pacemaker implantations by comparing the 2 devices. We analyzed the last consecutive 103 patients undergoing transcatheter aortic valve implantation with SAPIEN XT before SAPIEN 3 was used in the next 105 patients. To analyze permanent pacemaker implantations and new-onset intraventricular conduction abnormalities, patients with these conditions at baseline were excluded. Electrocardiograms were recorded at baseline, after the procedure, and before discharge. SAPIEN 3 was associated with higher device success (100% vs 92%; P=.005) and less paravalvular leakage (0% vs 7%; Ppacemaker implantations was 12.6% (23 of 183) with no difference between the 2 groups (SAPIEN 3: 12.5% [12 of 96] vs SAPIEN XT: 12.6% [11 of 87]; P=.99). SAPIEN 3 was associated with a higher rate of new-onset intraventricular conduction abnormalities (49% vs 27%; P=.007) due to a higher rate of fascicular blocks (17% vs 5%; P=.021). There was no statistically significant difference in transient (29% [20 of 69] vs persistent 19% [12 of 64]; P=.168) left bundle branch blocks (28% [19 of 69] vs 17% [11 of 64]; P=.154) when SAPIEN 3 was compared with SAPIEN XT. We found a trend toward a higher rate of new-onset intraventricular conduction abnormalities with SAPIEN 3 compared with SAPIEN XT, although this did not result in a higher permanent pacemaker implantation rate. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Management of aggressive periodontitis patient with implant supported prosthesis

Directory of Open Access Journals (Sweden)

Garima Jain

2015-01-01

Full Text Available Aggressive periodontitis (AgP comprises a group of rare, often severe, rapidly progressive forms of periodontitis which is characterized by an early age of clinical manifestations. It usually affects people under 30 years of age, but patients may be older. Microbiota associated are Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. The presence of highly pathogenic bacteria, severe periodontal bone destruction and the refractory nature of this disease tends to deter the clinician from placing implants in these patients. This case report demonstrates the placement of implants in a patient with AgP with successful 18 months follow-up.

Transcatheter Pulmonary Valve Replacement for Right Ventricular Outflow Tract Conduit Dysfunction After the Ross Procedure

DEFF Research Database (Denmark)

Gillespie, Matthew J; McElhinney, Doff B; Kreutzer, Jacqueline

2015-01-01

BACKGROUND: Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. METHODS: Retrospective review of databa......BACKGROUND: Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. METHODS: Retrospective review....... Of these, 56 (84%) received a Melody valve; in 5 of the 11 patients who did not, the implant was aborted due to concern for coronary artery compression, and 1 implanted patient required emergent surgery for left coronary compression. The RVOT gradient decreased from a median 38 mm Hg to 13.5 mm Hg (p

Dental Mesenchymal Stem Cell-Based Translational Regenerative Dentistry: From Artificial to Biological Replacement

Science.gov (United States)

Marei, Mona K.; El Backly, Rania M.

2018-01-01

Dentistry is a continuously changing field that has witnessed much advancement in the past century. Prosthodontics is that branch of dentistry that deals with replacing missing teeth using either fixed or removable appliances in an attempt to simulate natural tooth function. Although such “replacement therapies” appear to be easy and economic they fall short of ever coming close to their natural counterparts. Complications that arise often lead to failures and frequent repairs of such devices which seldom allow true physiological function of dental and oral-maxillofacial tissues. Such factors can critically affect the quality of life of an individual. The market for dental implants is continuously growing with huge economic revenues. Unfortunately, such treatments are again associated with frequent problems such as peri-implantitis resulting in an eventual loss or replacement of implants. This is particularly influential for patients having co-morbid diseases such as diabetes or osteoporosis and in association with smoking and other conditions that undoubtedly affect the final treatment outcome. The advent of tissue engineering and regenerative medicine therapies along with the enormous strides taken in their associated interdisciplinary fields such as stem cell therapy, biomaterial development, and others may open arenas to enhancing tissue regeneration via designing and construction of patient-specific biological and/or biomimetic substitutes. This review will overview current strategies in regenerative dentistry while overviewing key roles of dental mesenchymal stem cells particularly those of the dental pulp, until paving the way to precision/translational regenerative medicine therapies for future clinical use. PMID:29770323

Dental Mesenchymal Stem Cell-Based Translational Regenerative Dentistry: From Artificial to Biological Replacement

Directory of Open Access Journals (Sweden)

Mona K. Marei

2018-05-01

Full Text Available Dentistry is a continuously changing field that has witnessed much advancement in the past century. Prosthodontics is that branch of dentistry that deals with replacing missing teeth using either fixed or removable appliances in an attempt to simulate natural tooth function. Although such “replacement therapies” appear to be easy and economic they fall short of ever coming close to their natural counterparts. Complications that arise often lead to failures and frequent repairs of such devices which seldom allow true physiological function of dental and oral-maxillofacial tissues. Such factors can critically affect the quality of life of an individual. The market for dental implants is continuously growing with huge economic revenues. Unfortunately, such treatments are again associated with frequent problems such as peri-implantitis resulting in an eventual loss or replacement of implants. This is particularly influential for patients having co-morbid diseases such as diabetes or osteoporosis and in association with smoking and other conditions that undoubtedly affect the final treatment outcome. The advent of tissue engineering and regenerative medicine therapies along with the enormous strides taken in their associated interdisciplinary fields such as stem cell therapy, biomaterial development, and others may open arenas to enhancing tissue regeneration via designing and construction of patient-specific biological and/or biomimetic substitutes. This review will overview current strategies in regenerative dentistry while overviewing key roles of dental mesenchymal stem cells particularly those of the dental pulp, until paving the way to precision/translational regenerative medicine therapies for future clinical use.

Novel implant for peri-prosthetic proximal tibia fractures.

Science.gov (United States)

Tran, Ton; Chen, Bernard K; Wu, Xinhua; Pun, Chung Lun

2018-03-01

Repair of peri-prosthetic proximal tibia fractures is very challenging in patients with a total knee replacement or arthroplasty. The tibial component of the knee implant severely restricts the fixation points of the tibial implant to repair peri-prosthetic fractures. A novel implant has been designed with an extended flange over the anterior of tibial condyle to provide additional points of fixation, overcoming limitations of existing generic locking plates used for proximal tibia fractures. Furthermore, the screws fixed through the extended flange provide additional support to prevent the problem of subsidence of tibial component of knee implant. The design methodology involved extraction of bone data from CT scans into a flexible CAD format, implant design and structural evaluation and optimisation using FEM as well as prototype development and manufacture by selective laser melting 3D printing technology with Ti6Al4 V powder. A prototype tibia implant was developed based on a patient-specific bone structure, which was regenerated from the CT images of patient's tibia. The design is described in detail and being applied to fit up to 80% of patients, for both left and right sides based on the average dimensions and shape of the bone structure from a wide range of CT images. A novel tibial implant has been developed to repair peri-prosthetic proximal tibia fractures which overcomes significant constraints from the tibial component of existing knee implant. Copyright © 2018 Elsevier Ltd. All rights reserved.

Outcome of total knee replacement following explantation and cemented spacer therapy.

Science.gov (United States)

Ghanem, Mohamed; Zajonz, Dirk; Bollmann, Juliane; Geissler, Vanessa; Prietzel, Torsten; Moche, Michael; Roth, Andreas; Heyde, Christoph-E; Josten, Christoph

2016-01-01

Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation. A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient's group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation. No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data point out to the fact that a longer time interval between

Outcome of total knee replacement following explantation and cemented spacer therapy

Directory of Open Access Journals (Sweden)

Ghanem, Mohamed

2016-03-01

Full Text Available Background: Infection after total knee replacement (TKR is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation.Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient’s group comprised of 53% (18 males and 47% (16 females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years. We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11 reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation.Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation

Stock Versus CAD/CAM Customized Zirconia Implant Abutments - Clinical and Patient-Based Outcomes in a Randomized Controlled Clinical Trial

NARCIS (Netherlands)

Schepke, Ulf; Meijer, Henny J. A.; Kerdijk, Wouter; Raghoebar, Gerry M.; Cune, Marco

BackgroundSingle-tooth replacement often requires a prefabricated dental implant and a customized crown. The benefits of individualization of the abutment remain unclear. PurposeThis randomized controlled clinical trial aims to study potential benefits of individualization of zirconia implant

Abnormal bone formation induced by implantation of osteosarcoma-derived bone-inducing substance in the X-linked hypophosphatemic mouse

International Nuclear Information System (INIS)

Yoshikawa, H.; Masuhara, K.; Takaoka, K.; Ono, K.; Tanaka, H.; Seino, Y.

1985-01-01

The X-linked hypophosphatemic mouse (Hyp) has been proposed as a model for the human familial hypophosphatemia (the most common form of vitamin D-resistant rickets). An osteosarcoma-derived bone-inducing substance was subcutaneously implanted into the Hyp mouse. The implant was consistently replaced by cartilage tissue at 2 weeks after implantation. The cartilage matrix seemed to be normal, according to the histological examination, and 35sulphur ( 35 S) uptake was also normal. Up to 4 weeks after implantation the cartilage matrix was completely replaced by unmineralized bone matrix and hematopoietic bone marrow. Osteoid tissue arising from the implantation of bone inducing substance in the Hyp mouse showed no radiologic or histologic sign of calcification. These findings suggest that the abnormalities of endochondral ossification in the Hyp mouse might be characterized by the failure of mineralization in cartilage and bone matrix. Analysis of the effects of bone-inducing substance on the Hyp mouse may help to give greater insight into the mechanism and treatment of human familial hypophosphatemia

Implante percutâneo de valva aórtica: mito ou realidade? Percutaneous aortic aortic valve replacement: myth or reality?

Directory of Open Access Journals (Sweden)

Eduardo Keller Saadi

2008-03-01

Full Text Available A substituição valvar por prótese metálica ou biológica com o auxílio de circulação extracorpórea é o procedimento padrão-ouro para o tratamento da estenose aórtica calcificada. Embora os resultados sejam excelentes com a cirurgia convencional, alguns pacientes com idade avançada, doenças associadas, reoperações e disfunção ventricular esquerda grave apresentam alto risco cirúrgico. Nos últimos anos, técnicas de tratamento percutâneo foram desenvolvidas. A presente revisão tem por objetivo analisar a literatura desde o desenvolvimento experimental até a aplicação clínica desta nova modalidade de tratamento para pacientes com estenose aórtica grave e alto risco cirúrgico. O implante percutâneo de valva aórtica hoje vem sendo realizado por alguns centros e o cirurgião cardiovascular envolvido no tratamento das doenças valvares deve fazer parte deste desenvolvimento.Aortic valve replacement with mechanical or biological prosthesis with extracorporeal circulation is the gold-standard for the treatment of calcific aortic stenosis. Although the results are excellent with the conventional approach some elderly patients, with multiple high-risk comorbid conditions, reoperations and severe left ventricular dysfunction have high surgical risk. During the last years percutaneous techniques have been developed. The present study aim to analyse the literature, since the experimental development untill clinical application of this novel treatment in patients with high surgical risk aortic stenosis. Percutaneous implantation of aortic valve prosthesis is beeing done in some centers and the cardiovascular surgeon that treats valve disease should be involved in this development.

Dermis-Fat Graft in Children as Primary and Secondary Orbital Implant.

Science.gov (United States)

Quaranta-Leoni, Francesco M; Sposato, Sabrina; Raglione, Pietro; Mastromarino, Angelo

2016-01-01

To report the experience with the use of dermis-fat graft in the pediatric population and to evaluate the outcome of this procedure as a primary or secondary orbital implant. Case series. Analysis of the clinical charts of 22 patients. Age at the time of surgery ranged from 2.1 to 13 years. Three patients affected were submitted to evisceration with primary dermis-fat graft. Six patients had explantation of exposed implants and a replacement with a dermis-fat graft. Three patients had a dermis-fat graft to repair contracted sockets. Ten patients were affected by congenital anophthalmia: 4 patients had a primary dermis-fat graft, 6 patients had a removal of a socket expander, or an orbital spherical expander, or pellet expanders and a replacement with a dermis-fat graft. This study adheres to the principles outlined in the Declaration of Helsinki. The patients' follow up ranged between 2.5 and 8 years. Only 1 child who had a primary dermis-fat graft experienced excessive growth of the implant, managed by surgical debulking. In the end, all the patients showed satisfactory orbital volume along with adequate fornices. The dermis-fat graft as a primary implant may be useful in children with severe scleromalacia or following ocular trauma. It is a suitable option in children affected by congenital anophthalmia as it helps continued socket expansion. It can also be considered in the pediatric population to address the volume deficit following explantation of exposed implants and in contracted sockets.

Power harvesting using PZT ceramics embedded in orthopedic implants.

Science.gov (United States)

Chen, Hong; Liu, Ming; Jia, Chen; Wang, Zihua

2009-09-01

Battery lifetime has been the stumbling block for many power-critical or maintenance-free real-time embedded applications, such as wireless sensors and orthopedic implants. Thus a piezoelectric material that could convert human motion into electrical energy provides a very attractive solution for clinical implants. In this work, we analyze the power generation characteristics of stiff lead zirconate titanate (PZT) ceramics and the equivalent circuit through extensive experiments. Our experimental framework allows us to explore many important design considerations of such a PZT-based power generator. Overall we can achieve a PZT element volume of 0.5 x 0.5 x 1.8 cm, which is considerably smaller than the results reported so far. Finally, we outline the application of our PZT elements in a total knee replacement (TKR) implant.

Noninvasive method for retrieval of broken dental implant abutment screw

Directory of Open Access Journals (Sweden)

Jagadish Reddy Gooty

2014-01-01

Full Text Available Dental implants made of titanium for replacement of missing teeth are widely used because of ease of technical procedure and high success rate, but are not free of complications and may fail. Fracturing of the prosthetic screw continues to be a problem in restorative practice and great challenge to remove the fractured screw conservatively. This case report describes and demonstrates the technique of using an ultrasonic scaler in the removal of the fracture screw fragment as a noninvasive method without damaging the hex of implants.

Long-term amnioinfusion through a subcutaneously implanted amniotic fluid replacement port system for treatment of PPROM in humans.

Science.gov (United States)

Tchirikov, Michael; Steetskamp, Joscha; Hohmann, Manfred; Koelbl, Heinz

2010-09-01

To introduce a novel method for the treatment of PPROM (preterm premature rupture of membranes) using continuous amnioinfusion via a subcutaneously implanted port system. After development and testing since 2001 in a fetal sheep model, the port system has been successfully implanted in two humans with PPROM. In the first case, the subcutaneous port system was implanted during the 23rd week of gestation in a 39-year-old 5th-gravida with PPROM since the 18th week of gestation; in the second case, the port system was implanted during the 24th week of gestation in a 27-year-old 3rd gravida with PPROM since the 21st week of gestation. After port implantation, 100ml/h saline solution was infused intermittently into the amniotic cavity. The whole course of treatment was supported by tocolysis. In the cases presented, gestation was terminated by cesarean section, in one case in the 29th week of gestation, and in the other case in the 30th week. The newborns showed no signs of lung hypoplasia and were successfully extubated on the 1st or 2nd day after delivery. Six months later the children did not exhibit any deviation from the normal development. Long-term amnioinfusion via a subcutaneously implanted port system could be used in humans with PPROM for prolongation of pregnancy and to avoid lung hypoplasia. Prospective randomized studies are ongoing. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

THE INFLUENCE OF SURFACE-FREE ENERGY ON SUPRAGINGIVAL AND SUBGINGIVAL PLAQUE MICROBIOLOGY - AN IN-VIVO STUDY ON IMPLANTS

NARCIS (Netherlands)

QUIRYNEN, M; VANDERMEI, HC; BOLLEN, CML; VANDENBOSSCHE, LH; DOORNBUSCH, GI; VANSTEENBERGHE, D; BUSSCHER, HJ

THE INFLUENCE OF SURFACE FREE ENERGY on supra- and subgingival plaque microbiology was examined in 9 patients with functional fixed prostheses supported by endosseous titanium implants. Two abutments (trans-mucosal part of the 2 stage implant) were replaced by either a new titanium abutment or a

Immediate loading of tapered implants placed in postextraction sockets: retrospective analysis of the 5-year clinical outcome.

Science.gov (United States)

Mura, Priamo

2012-08-01

The use of immediate implant loading protocols delivers obvious benefits to the patient. When applied in healed sites, this has not only been well documented in the totally edentolous mandible but has also been documented and reported to be predictable in the upper jaw, and in cases of partial edentoulism, as well. A further application of immediate loading protocol, although still controversial, especially when replacing single maxillary teeth in the anterior zone, is the immediate implant placement and provisionalization in postextractive sockets. In consideration of the oxidized surface promoting bone healing and the tapered shape of the implant body, the Replace Select Tapered TiUnite implants have been used for many years in our clinic when facing these clinical situations. This article will report about our long-term clinical experience with such implants and the relevant role of a correct surgical and prosthetic treatment planning. The aim of this retrospective study was to report on the 5-year clinical and radiologic outcome of patients treated with Replace Select Tapered TiUnite implants when used according to an immediate loading protocol in postextraction sites. In routine practice, 56 consecutive patients were treated with 79 implants. The patients, 23 males and 33 females, had a mean age of 50.9 years, range 21-76 years, at implant placement. Forty-seven implants were placed in the maxilla and 32 implants were placed in the mandible. All implants were placed in postextraction sites and were immediately loaded. Provisional restorations were delivered within 2 hours from surgery and all were in occlusion. Forty-three patients received a single implant while in the remaining 13 patients the implants were splinted. Definitive prosthetic restoration was delivered within 1 to 4 months following implant placement. Evaluations of soft tissue health and marginal bone remodeling were conducted. An independent radiologist performed the radiographic evaluation

Nanotubular surface modification of metallic implants via electrochemical anodization technique.

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Wang, Lu-Ning; Jin, Ming; Zheng, Yudong; Guan, Yueping; Lu, Xin; Luo, Jing-Li

2014-01-01

Due to increased awareness and interest in the biomedical implant field as a result of an aging population, research in the field of implantable devices has grown rapidly in the last few decades. Among the biomedical implants, metallic implant materials have been widely used to replace disordered bony tissues in orthopedic and orthodontic surgeries. The clinical success of implants is closely related to their early osseointegration (ie, the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant), which relies heavily on the surface condition of the implant. Electrochemical techniques for modifying biomedical implants are relatively simple, cost-effective, and appropriate for implants with complex shapes. Recently, metal oxide nanotubular arrays via electrochemical anodization have become an attractive technique to build up on metallic implants to enhance the biocompatibility and bioactivity. This article will thoroughly review the relevance of electrochemical anodization techniques for the modification of metallic implant surfaces in nanoscale, and cover the electrochemical anodization techniques used in the development of the types of nanotubular/nanoporous modification achievable via electrochemical approaches, which hold tremendous potential for bio-implant applications. In vitro and in vivo studies using metallic oxide nanotubes are also presented, revealing the potential of nanotubes in biomedical applications. Finally, an outlook of future growth of research in metallic oxide nanotubular arrays is provided. This article will therefore provide researchers with an in-depth understanding of electrochemical anodization modification and provide guidance regarding the design and tuning of new materials to achieve a desired performance and reliable biocompatibility.

Effect of total lumbar disc replacement on lumbosacral lordosis.

Science.gov (United States)

Kasliwal, Manish K; Deutsch, Harel

2012-10-01

Original article : To study effect of lumbar disc replacement on lumbosacral lordosis. There has been a growing interest in total disc replacement (TDR) for back pain with the rising concern of adjacent segment degeneration. Lumbar fusion surgery has been shown to lead to decrease in lumbar lordosis, which may account for postfusion pain resulting in less acceptable clinical outcome after successful fusion. TDR has recently emerged as an alternative treatment for back pain. There have been very few studies reporting lumbar sagittal outcome after TDR. Retrospective study of radiographic data of 17 patients who underwent TDR for single level degenerative disc disease at the author's institution was carried out. Study included measurement of preoperative and postoperative segmental and global lumbar lordosis and angle of lordosis. Patients age varied from 19 to 54 (mean, 35) years. Follow-up ranged from 12 to 24 months. TDR was performed at L4-5 level in 3 patients and L5-S1 level in 14 patients. The average values for segmental lordosis, global lordosis, and angle of lordosis at the operated level before and after surgery were 17.3, 49.7, and 8.6 degrees and 21.6, 54, and 9.5 degrees, respectively. There was a trend toward significant (P=0.02) and near significant (P=0.057) increase in segmental and global lordosis, respectively after TDR. Although prosthesis increased angle of lordosis at the level implanted in majority of the patients, the difference in preoperative and postoperative angle of lordosis was not significant (P=0.438). In addition, there was no correlation between the angle of implant of chosen and postoperative angle of lordosis at the operated level. The effect of TDR on sagittal balance appears favorable with an increase in global and segmental lumbar lordosis after single level TDR for degenerative disc disease. The degree of postoperative angle of lordosis was not affected by the angle of implant chosen at the operated level and varied

Total Artificial Heart Implantation After Undifferentiated High-Grade Sarcoma Excision.

Science.gov (United States)

Kremer, Jamila; Farag, Mina; Arif, Rawa; Brcic, Andreas; Sabashnikov, Anton; Schmack, Bastian; Popov, Aron-Frederik; Karck, Matthias; Dohmen, Pascal M; Ruhparwar, Arjang; Weymann, Alexander

2016-11-02

BACKGROUND Total artificial heart (TAH) implantation in patients with aggressive tumor infiltration of the heart can be challenging. CASE REPORT We report on a patient with a rare primary undifferentiated high-grade spindle cell sarcoma of the mitral valve and in the left atrium, first diagnosed in 2014. The referring center did a first resection in 2014. In the course of 17 months, computer tomography (CT) scan again showed massive invasion of the mitral valve and left atrium. Partial resection and mitral valve replacement was not an option. We did a subtotal heart excision with total artificial heart implantation. In this report we discuss complications, risk factors, and perioperative management of this patient. CONCLUSIONS Patients with aggressive tumors of the heart can be considered for TAH implantation.

Spine imaging after lumbar disc replacement: pitfalls and current recommendations

OpenAIRE

Robinson, Yohan; Sand?n, Bengt

2009-01-01

Abstract Background Most lumbar artificial discs are still composed of stainless steel alloys, which prevents adequate postoperative diagnostic imaging of the operated region when using magnetic resonance imaging (MRI). Thus patients with postoperative radicular symptoms or claudication after stainless steel implants often require alternative diagnostic procedures. Methods Possible complications of lumbar total disc replacement (TDR) are reviewed from the available literature and imaging reco...

Awareness, attitudes, need and demand on replacement of missing teeth among a group of partially dentate patients attending a University Dental Hospital.

Science.gov (United States)

Jayasinghe, Rasika Manori; Perera, Janana; Jayasinghe, Vajira; Thilakumara, Indika P; Rasnayaka, Sumudu; Shiraz, Muhammad Hanafi Muhammad; Ranabahu, Indra; Kularatna, Sanjeewa

2017-07-27

Our objective was to assess awareness, attitudes, need and demand on replacement of missing teeth according to edentulous space, age, gender, ethnicity, educational level and socio-economical status of the patient. 76.2% of the study group was opined that the missing teeth should be replaced by prosthetic means. Majority were keen in getting them replaced mainly for the comfort in mastication. Although 77.9 and 32.9% were aware of the removable prostheses and implants respectively, only 25.2% knew about tooth supported bridges as an option of replacement of missing teeth. Participants' awareness on tooth and implant supported prostheses is at a higher level. Participants' opinion on need of regular dental visit was statistically significant when gender, ethnicity and education level were considered. The highest demand for replacement of missing teeth was observed in Kennedy class I and II situations in both upper and lower arches. Demand for fixed prostheses was significantly highest in Kennedy class II in upper and lower arches. In conclusion, although removable prosthodontic options are known to most of the patients, their awareness on tooth and implant supported prostheses is also at a higher level. The highest demand for replacement of missing teeth is by patients with Kennedy class I and II situations whereas Kennedy class II being the category with highest demand for fixed prostheses. We recommend that the location of missing teeth to be considered as a priority when educating patients on the most appropriate prosthetic treatment options. Dentists' involvement in educating patients on prosthetic options needs to be improved.

Preliminary fabrication and characterization of electron beam melted Ti–6Al–4V customized dental implant

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Ravikumar Ramakrishnaiah

2017-05-01

Full Text Available The current study was aimed to fabricate customized root form dental implant using additive manufacturing technique for the replacement of missing teeth. The root form dental implant was designed using Geomagic™ and Magics™, the designed implant was directly manufactured by layering technique using ARCAM A2™ electron beam melting system by employing medical grade Ti–6Al–4V alloy powder. Furthermore, the fabricated implant was characterized in terms of certain clinically important parameters such as surface microstructure, surface topography, chemical purity and internal porosity. Results confirmed that, fabrication of customized dental implants using additive rapid manufacturing technology offers an attractive method to produce extremely pure form of customized titanium dental implants, the rough and porous surface texture obtained is expected to provide better initial implant stabilization and superior osseointegration.

Long-term survivorship of stemless anatomical shoulder replacement.

Science.gov (United States)

Beck, Sascha; Beck, Verena; Wegner, Alexander; Dudda, Marcel; Patsalis, Theodor; Jäger, Marcus

2018-01-24

Like in many other joints, current shoulder replacement designs aim at bone preservation. According to the literature available, stemless total shoulder arthroplasty (TSA) compares favourably with stemmed designs in terms of function and survivorship of the implant. However, long-term results of stemless shoulder arthroplasty are still missing. Therefore, the aim of the present study was to evaluate long-term results of stemless anatomical TSA. Between 2006 and 2009, 51 shoulders in 46 patients were resurfaced using the Biomet Total Evolutive Shoulder System (TESS). Thirty-one shoulders in 26 patients who were aged 66.7 ± 10.0 (range 34-82) years were available for review at a mean follow-up of 94.7 ± 11.3 (76-124) months. The implant survival rate was 93.5% at eight years. The overall revision rate of the TESS implant was 9.7%. Radiolucent lines were found on the glenoid side of the TESS arthroplasty in 90.9% of the cases. All stemless humeral corolla implants showed solid fixation at follow-up. Clinical scores significantly improved at long-term follow-up (VAS from 8.1 ± 0.9 to 1.0 ± 1.2, p < 0.001; Quick-DASH from 67.9 ± 13.5 to 18.7 ± 16.5, p < 0.001 and Constant score from 14.7 ± 6.1 to 68.8 ± 13.2, p < 0.001). Stemless TSA has stood the test of time at eight years in terms of clinical scores, radiographic loosening, complication rates and implant survivorship.

Midterm Results of Aortic Valve Replacement with Cryopreserved Homografts

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Emre Özker

2012-06-01

Full Text Available Objective: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.Materials and Methods: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%, truncus arteriosus in 6 patients (15%, and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35% patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.Results: The 30-day postoperative mortality rate was 12.5% (5 patients. There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003. The last follow up showed that the 27 (82% patients had a normal left ventricular function.Conclusion: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

Early implant placement for a patient with ectodermal dysplasia: Thirteen years of clinical care.

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Knobloch, Lisa A; Larsen, Peter E; Saponaro, Paola C; L'Homme-Langlois, Emilie

2017-11-29

Patients with ectodermal dysplasia have abnormalities of 2 or more structures that originate from the ectoderm. The oral manifestations often include the congenital absence of teeth and malformed teeth. This clinical report describes the interdisciplinary care from childhood through the definitive dental rehabilitation completed at skeletal maturation to replace the missing teeth in a patient with ectodermal dysplasia. Treatment began at 9 years of age with an implant-assisted mandibular overdenture to improve function and replace the missing mandibular teeth. Orthodontic treatment for the consolidation of space, composite resin restorations, and interim removable dental prostheses were provided to improve esthetics and replace the missing maxillary teeth. Skeletal growth was monitored, and orthognathic surgery was performed at the cessation of growth. The definitive rehabilitation consisted of a mandibular fixed dental prosthesis supported by dental implants and a maxillary removable dental prosthesis to restore the patient to esthetics and function. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Sistema de fabrico rápido de implantes ortopédicos Rapid manufacturing system of orthopedics implants

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Carlos Relvas

2009-06-01

Full Text Available Este estudo teve como objectivo o desenvolvimento uma metodologia de fabrico rápido de implantes ortopédicos, em simultaneidade com a intervenção cirúrgica, considerando duas potenciais aplicações na área ortopédica: o fabrico de implantes anatomicamente adaptados e o fabrico de implantes para substituição de perdas ósseas. A inovação do trabalho desenvolvido consiste na obtenção in situ da geometria do implante, através da impressão directa de um material elastomérico (polivinilsiloxano que permite obter com grande exactidão a geometria pretendida. Após digitalização do modelo obtido em material elastomérico, o implante final é fabricado por maquinagem recorrendo a um sistema de CAD/CAM dedicado. O implante após esterilização, pode ser colocado no paciente. O conceito foi desenvolvido com recurso a tecnologias disponíveis comercialmente e de baixo custo. O mesmo foi testado sob a forma de uma artroplastia da anca realizada in vivo numa ovelha. O acréscimo de tempo de cirurgia foi de 80 minutos sendo 40 directamente resultantes do processo de fabrico do implante. O sistema desenvolvido revelou-se eficiente no alcance dos objectivos propostos, possibilitando o fabrico de um implante durante um período de tempo perfeitamente compatível com o tempo de cirurgia.This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD

Implant Gigi One-Piece vs Two-Pieces dalam Praktek Sehari-Hari

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Dian Lestari Kurnia

2014-12-01

prosedur bedah dan prosedur prostetik lebih sederhana. Desain ini juga meniadakan celah mikro pada perbatasan implant dan abutment. Desain implant gigi one-piece memiliki keterbatasan pada pilihan prosedur prostetik apabila dibandingkan dengan desain implant gigi two-pieces.   One-Piece Versus Two-pieces Tooth Implant In Daily Practice. Implant had been a gold standard to replace missing tooth. However, implant marketed today was considered complex, and needs a second surgery. Complications may occur such as screw loosening or fracture and the presence of micro gap at implant-abutment-junction that is found causing fixture failure. The one-piece-implant design may offer some advantages. Purpose: this paper was aimed to discuss the pros and cons of one-piece-implants and two-piece-implants. Case 1 A 43-year-old woman came to place an implant on #16. The available bone height was 5 mm. A trans alveolar sinus lift procedure was performed with 0,5 cc allograft. A 12 mm one-piece-implant was inserted. Case 2 A 24-year-old woman came to place an implant on #46. The available bone height was 12 mm and a 10 mm two-piece-implant was inserted. Discussion: One-piece-implant offers some advantage. It needs no second surgery, easier placement protocol, and more natural prosthetic procedures. The design is preventing the failure in implant-abutment-junction failure. The absence of micro gap in one-piece-implant seems superior in preventing crestal bone resorption. However, the prosthetic option was limited in one-piece-implant. Two-piece-implant offers more choices in prosthetic abutment. Conclusion: One-piece-implant was easier and provide simple protocol with limited choice on prosthetic.

A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

Science.gov (United States)

Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

2015-12-01

We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (Prisk factor for overall mortality hazard ratio (hazard ratio, 2.5; confidence interval, 1.1-4.2; P = .018). The use of transcatheter aortic valve replacement in patients with an intermediate- to high-risk profile was associated with a significantly higher incidence of perioperative complications and decreased survival at short- and mid-term when compared with conventional surgery and sutureless valve implantation. Copyright © 2015 The American Association for Thoracic Surgery. Published by

Bioactive Coatings for Orthopaedic Implants—Recent Trends in Development of Implant Coatings

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Bill G. X. Zhang

2014-07-01

Full Text Available Joint replacement is a major orthopaedic procedure used to treat joint osteoarthritis. Aseptic loosening and infection are the two most significant causes of prosthetic implant failure. The ideal implant should be able to promote osteointegration, deter bacterial adhesion and minimize prosthetic infection. Recent developments in material science and cell biology have seen the development of new orthopaedic implant coatings to address these issues. Coatings consisting of bioceramics, extracellular matrix proteins, biological peptides or growth factors impart bioactivity and biocompatibility to the metallic surface of conventional orthopaedic prosthesis that promote bone ingrowth and differentiation of stem cells into osteoblasts leading to enhanced osteointegration of the implant. Furthermore, coatings such as silver, nitric oxide, antibiotics, antiseptics and antimicrobial peptides with anti-microbial properties have also been developed, which show promise in reducing bacterial adhesion and prosthetic infections. This review summarizes some of the recent developments in coatings for orthopaedic implants.

Cranial implant design using augmented reality immersive system.

Science.gov (United States)

Ai, Zhuming; Evenhouse, Ray; Leigh, Jason; Charbel, Fady; Rasmussen, Mary

2007-01-01

Software tools that utilize haptics for sculpting precise fitting cranial implants are utilized in an augmented reality immersive system to create a virtual working environment for the modelers. The virtual environment is designed to mimic the traditional working environment as closely as possible, providing more functionality for the users. The implant design process uses patient CT data of a defective area. This volumetric data is displayed in an implant modeling tele-immersive augmented reality system where the modeler can build a patient specific implant that precisely fits the defect. To mimic the traditional sculpting workspace, the implant modeling augmented reality system includes stereo vision, viewer centered perspective, sense of touch, and collaboration. To achieve optimized performance, this system includes a dual-processor PC, fast volume rendering with three-dimensional texture mapping, the fast haptic rendering algorithm, and a multi-threading architecture. The system replaces the expensive and time consuming traditional sculpting steps such as physical sculpting, mold making, and defect stereolithography. This augmented reality system is part of a comprehensive tele-immersive system that includes a conference-room-sized system for tele-immersive small group consultation and an inexpensive, easily deployable networked desktop virtual reality system for surgical consultation, evaluation and collaboration. This system has been used to design patient-specific cranial implants with precise fit.

Ion implantation in advanced planar and vertical devices

International Nuclear Information System (INIS)

Gossmann, Hans-Joachim L.

2005-01-01

The extent ('gate overlap') and slope ('abruptness') of the lateral junction are quickly replacing vertical junction depth as the most important physical junction metrics in advanced device architectures. This is in particular true for ultra-thin body devices, where the vertical junction is limited by a geometric constraint. The optimum gate overlap is quite small, or may even be negative, making a process without the need of high-tilt implantation feasible, even for dopant activation with negligible diffusion by flash annealing or laser thermal processing. Dopant activation by solid phase epitaxial regrowth might require high-tilt implants for a positive overlap. The use of such implants, however, is expected to lead to severe gate-poly and gate-oxide degradation. Scaling the 150 nm technology has drastically shrunk the overlap, accomplished by an equally aggressive reduction in thermal budget. For a 65 nm node device, a significant fraction of the overlap originates in the as-implanted dopant profile and the importance of diffusion is diminished. As a consequence small changes in the as-implanted profile are beginning to have a disproportionate impact on device characteristics. Small angular deviations of the incident beam from normal incidence, as seen by the wafer, lead to large changes in on-current. This can be alleviated significantly by a quad implant provided the tilt-angle is sufficiently large, in the order >5 deg.

Immediate loading versus immediate provisionalization of maxillary single-tooth replacements: a prospective randomized study with BioComp implants

NARCIS (Netherlands)

Lindeboom, Jerome A.; Frenken, Joost W.; Dubois, Leander; Frank, Michael; Abbink, Ingmar; Kroon, Frans H.

2006-01-01

PURPOSE: The aim of this prospective randomized study was to evaluate the clinical outcome of immediately loaded solid plasma sprayed (TPS) BioComp (BioComp Industries BV, Vught, The Netherlands) implants versus immediate provisionalized but non-loaded BioComp implants in the anterior and premolar

Reliable and energy-efficient communications for wireless biomedical implant systems.

Science.gov (United States)

Ntouni, Georgia D; Lioumpas, Athanasios S; Nikita, Konstantina S

2014-11-01

Implant devices are used to measure biological parameters and transmit their results to remote off-body devices. As implants are characterized by strict requirements on size, reliability, and power consumption, applying the concept of cooperative communications to wireless body area networks offers several benefits. In this paper, we aim to minimize the power consumption of the implant device by utilizing on-body wearable devices, while providing the necessary reliability in terms of outage probability and bit error rate. Taking into account realistic power considerations and wireless propagation environments based on the IEEE P802.l5 channel model, an exact theoretical analysis is conducted for evaluating several communication scenarios with respect to the position of the wearable device and the motion of the human body. The derived closed-form expressions are employed toward minimizing the required transmission power, subject to a minimum quality-of-service requirement. In this way, the complexity and power consumption are transferred from the implant device to the on-body relay, which is an efficient approach since they can be easily replaced, in contrast to the in-body implants.

Transcatheter aortic valve implantation for a failed bio-bentall in patients with Marfan syndrome.

Science.gov (United States)

Beigel, Roy; Siegel, Robert J; Kahlon, Ravi S; Jilaihawi, Hasan; Cheng, Wen; Makkar, Raj R

2014-01-01

Patients with Marfan syndrome are at risk for ascending aortic dilation and dissection at the level of the aortic sinuses, making aortic root and valve replacement common. Patients undergoing an aortic root replacement with concomitant replacement of the aortic valve with a bioprosthesis (Bio-Bentall) are predisposed to bioprosthesis failure. Transcatheter aortic valve implantation (TAVI) has become an option for aortic valve replacement, avoiding cardiopulmonary bypass and/or median sternotomy. We present the first 2 reported patients with Marfan syndrome who underwent a valve-in-valve TAVI in the setting of a prior Bio-Bentall. © 2014 S. Karger AG, Basel.

Quality of YouTube TM videos on dental implants.

Science.gov (United States)

Abukaraky, A; Hamdan, A-A; Ameera, M-N; Nasief, M; Hassona, Y

2018-07-01

Patients search YouTube for health-care information. To examine what YouTube offers patients seeking information on dental implants, and to evaluate the quality of provided information. A systematic search of YouTube for videos containing information on dental implants was performed using the key words Dental implant and Tooth replacement. Videos were examined by two senior Oral and Maxillofacial Surgery residents who were trained and calibrated to perform the search. Initial assessment was performed to exclude non- English language videos, duplicate videos, conference lectures, and irrelevant videos. Included videos were analyzed with regard to demographics and content's usefulness. Information for patients available from the American Academy of Implant Dentistry, European Association of Osseointegration, and British Society of Restorative Dentistry were used for benchmarking. A total of 117 videos were analyzed. The most commonly discussed topics were related to procedures involved in dental implantology (76.1%, n=89), and to the indications for dental implants (58.1%, n=78). The mean usefulness score of videos was poor (6.02 ±4.7 [range 0-21]), and misleading content was common (30.1% of videos); mainly in topics related to prognosis and maintenance of dental implants. Most videos (83.1%, n=97) failed to mention the source of information presented in the video or where to find more about dental implants. Information about dental implants on YouTube is limited in quality and quantity. YouTube videos can have a potentially important role in modulating patients attitude and treatment decision regarding dental implants.

Prosthodontic maintenance of overdentures on zirconia implants: 1-year results of a randomized controlled trial.

Science.gov (United States)

Osman, Reham B; Ma, Sunyoung

2014-01-01

The purpose of this study was to determine the prosthodontic outcomes of one-piece zirconia implants and their attachment systems in edentulous participants with maxillary and mandibular overdentures after 1 year of a randomized controlled trial. Random allocation of 24 edentulous participants (age range: 45 to 86 years) into titanium (control) or zirconia (test) groups using onepiece implants and a planned unsplinted prosthodontic design was performed. Four maxillary implants (one midpalatal; three anterior crestal) and three mandibular implants (one midsymphyseal; two bilateral distal) were conventionally loaded with the overdentures. Similar attachment systems were used throughout: ball abutment-type patrices (diameter: 2.25 to 3.1 mm as part of the one-piece implants) and custommade plastic matrices (with or without metal housings depending on the patrix size). Prosthodontic outcomes were documented during the first year of the clinical trial. Following three deaths and two dropouts, there were 19 participants who were available at the 1-year recall. Of these participants, 3 had early maxillary implant failure and had to be converted to conventional maxillary complete dentures opposing mandibular implant overdentures. There were 79 maintenance events, 34 in the titanium (control) group and 45 in the zirconia (test) group. Patrix loss occurred as a result of three zirconia implant fractures (one mandibular and two crestal maxillary implants). Maintenance events were principally the replacement of matrices and overdenture fracture. Although relines and replacement overdentures also occurred, overall there were no significant differences in prosthodontic maintenance between the control and test groups. A six-field prosthodontic-success analysis table showed no statistically significant difference between the two groups; however, 50% of participants in each group were allocated to the retreatment (repair) field, which produced a low prosthodontic success rate

Orbital implants: State-of-the-art review with emphasis on biomaterials and recent advances.

Science.gov (United States)

Baino, Francesco; Potestio, Isabel

2016-12-01

In the treatment of severe oculo-orbital traumas, intraocular malignancies or other life-threatening conditions it is sometimes necessary to surgically remove the patient's diseased eye. Following the removal of the eye, an orbital implant is inserted into the anophthalmic socket in order to provide satisfactory volume replacement and restore the aesthetic appearance of a normal eye. Over the last decades, the implant design and the criteria of materials selection evolved from simple non-porous polymeric sphere to devices with more complex shape and functionalities for ensuring better clinical outcomes in the long-term. Polymeric and ceramic porous implants have gained prominence since their highly interconnected porous architecture allows them to act as a passive framework for fibrovascular in-growth offering reduced complication rates and the possibility of pegging to enhance the motility of the artificial eye. However, there are still drawbacks to these materials. Some critical aspects of today's orbital implants include the risk of migration and extrusion, postoperative infections and low motility transmitted to the aesthetic ocular prosthesis. Hence, the development of novel biomaterials with enhanced functionalities (e.g. angiogenesis, antibacterial effect, in situ mouldability) which enable an improved outcome of eye replacement is more than ever desirable and represents one of the most challenging topics of research in the field of ocular implants. This review summarizes the evolution of orbital implants and provides an overview of the most recent advances in the field as well as some critical remarks for materials design, selection, characterization and translation to clinical applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Guidelines for optimization of planar HDR implants

International Nuclear Information System (INIS)

Zwicker, R.D.; Schmidt-Ullrich, R.

1996-01-01

Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

Predicting the Failure of Dental Implants Using Supervised Learning Techniques

Directory of Open Access Journals (Sweden)

Chia-Hui Liu

2018-05-01

Full Text Available Prosthodontic treatment has been a crucial part of dental treatment for patients with full mouth rehabilitation. Dental implant surgeries that replace conventional dentures using titanium fixtures have become the top choice. However, because of the wide-ranging scope of implant surgeries, patients’ body conditions, surgeons’ experience, and the choice of implant system should be considered during treatment. The higher price charged by dental implant treatments compared to conventional dentures has led to a rush among medical staff; therefore, the future impact of surgeries has not been analyzed in detail, resulting in medial disputes. Previous literature on the success factors of dental implants is mainly focused on single factors such as patients’ systemic diseases, operation methods, or prosthesis types for statistical correlation significance analysis. This study developed a prediction model for providing an early warning mechanism to reduce the chances of dental implant failure. We collected the clinical data of patients who received artificial dental implants at the case hospital for a total of 8 categories and 20 variables. Supervised learning techniques such as decision tree (DT, support vector machines, logistic regressions, and classifier ensembles (i.e., Bagging and AdaBoost were used to analyze the prediction of the failure of dental implants. The results show that DT with both Bagging and Adaboost techniques possesses the highest prediction performance for the failure of dental implant (area under the receiver operating characteristic curve, AUC: 0.741; the analysis also revealed that the implant systems affect dental implant failure. The model can help clinical surgeons to reduce medical failures by choosing the optimal implant system and prosthodontics treatments for their patients.

Oxidized zirconium: a potentially longer lasting hip implant

International Nuclear Information System (INIS)

Good, V.; Widding, K.; Hunter, G.; Heuer, D.

2005-01-01

Because younger, more active patients are receiving total hip replacements, it is necessary to develop materials, which would increase the life span of the implants and challenge their wear potential under adverse conditions. Oxidized zirconium (OxZr) is a metal with the surface transformed to ceramic by oxidation that offers low fracture risk and excellent abrasion resistance. This study compared wear of polyethylene (non-irradiated and highly crosslinked) with OxZr and CoCr heads under smooth and rough (clinically relevant) conditions. Wear was up to 15-fold less and up to 4-fold fewer particles were produced when coupled with OxZr than with CoCr, demonstrating that OxZr heads should increase clinical implant longevity

Anti-inflammatory and Antibacterial Effects of Covalently Attached Biomembrane-Mimic Polymer Grafts on Gore-Tex Implants.

Science.gov (United States)

Jin, Young Ju; Kang, Sunah; Park, Pona; Choi, Dongkil; Kim, Dae Woo; Jung, Dongwook; Koh, Jaemoon; Jeon, Joohee; Lee, Myoungjin; Ham, Jiyeon; Seo, Ji-Hun; Jin, Hong-Ryul; Lee, Yan

2017-06-07

Expanded polytetrafluoroethylene (ePTFE), also known as Gore-Tex, is widely used as an implantable biomaterial in biomedical applications because of its favorable mechanical properties and biochemical inertness. However, infection and inflammation are two major complications with ePTFE implantations, because pathogenic bacteria can inhabit the microsized pores, without clearance by host immune cells, and the limited biocompatibility can induce foreign body reactions. To minimize these complications, we covalently grafted a biomembrane-mimic polymer, poly(2-methacryloyloxylethyl phosphorylcholine) (PMPC), by partial defluorination followed by UV-induced polymerization with cross-linkers on the ePTFE surface. PMPC grafting greatly reduced serum protein adsorption as well as fibroblast adhesion on the ePTFE surface. Moreover, the PMPC-grafted ePTFE surface exhibited a dramatic inhibition of the adhesion and growth of Staphylococcus aureus, a typical pathogenic bacterium in ePTFE implants, in the porous network. On the basis of an analysis of immune cells and inflammation-related factors, i.e., transforming growth factor-β (TGF-β) and myeloperoxidase (MPO), we confirmed that inflammation was efficiently alleviated in tissues around PMPC-grafted ePTFE plates implanted in the backs of rats. Covalent PMPC may be an effective strategy for promoting anti-inflammatory and antibacterial functions in ePTFE implants and to reduce side effects in biomedical applications of ePTFE.

Managing infection in the revision total hip replacement patient.

Science.gov (United States)

Halley, D K

1993-01-01

Deep infection is one of the most devastating complications in total hip replacement. This dreaded complication is presented in considerable detail with special emphasis on prevention, diagnosis, and various methods of surgical and antibiotic treatment. Basic fundamentals of antibiotic therapy are reviewed. In addition, guidelines are given for the indications of surgical intervention, the type and staging of operative procedures, with detailed techniques of the various operative procedures used to treat the infected total hip implant patient.

Critical appraisal of cardiac implantable electronic devices: complications and management

Directory of Open Access Journals (Sweden)

Padeletti L

2011-09-01

Full Text Available Luigi Padeletti1, Giosuè Mascioli2, Alessandro Paoletti Perini1, Gino Grifoni1, Laura Perrotta1, Procolo Marchese3, Luca Bontempi3, Antonio Curnis31Istituto di Clinica Medica e Cardiologia, Università degli Studi di Firenze, Italia; 2Elettrofisiologia, Istituto Humanitas Gavazzeni, Bergamo, Italia; 3Elettrofisiologia, Spedali Civili, Brescia, ItaliaAbstract: Population aging and broader indications for the implant of cardiac implantable electronic devices (CIEDs are the main reasons for the continuous increase in the use of pacemakers (PMs, implantable cardioverter-defibrillators (ICDs and devices for cardiac resynchronization therapy (CRT-P, CRT-D. The growing burden of comorbidities in CIED patients, the greater complexity of the devices, and the increased duration of procedures have led to an augmented risk of infections, which is out of proportion to the increase in implantation rate. CIED infections are an ominous condition, which often implies the necessity of hospitalization and carries an augmented risk of in-hospital death. Their clinical presentation may be either at pocket or at endocardial level, but they can also manifest themselves with lone bacteremia. The management of these infections requires the complete removal of the device and subsequent, specific, antibiotic therapy. CIED failures are monitored by competent public authorities, that require physicians to alert them to any failures, and that suggest the opportune strategies for their management. Although the replacement of all potentially affected devices is often suggested, common practice indicates the replacement of only a minority of devices, as close follow-up of the patients involved may be a safer strategy. Implantation of a PM or an ICD may cause problems in the patients' psychosocial adaptation and quality of life, and may contribute to the development of affective disorders. Clinicians are usually unaware of the psychosocial impact of implanted PMs and ICDs. The

The Role of Bioceramics Coating in Dental Implant Reliability and Success

Directory of Open Access Journals (Sweden)

Mortazavi V

2000-05-01

Full Text Available Characterization of bioceramics coating and evaluation of the influence of kind of coating on"nthe implantation has been developed in recent years."nDifferent bioceramics coating like calcium phosphate, hydroxyapatite, fluorapatite and bioglass were"ncoated on dental and orthopedic implants. In-vitro and in-vivo experiments were done for evolution of"nimplant success and reliability and study of factors, which may influence the results."nResearches indicate that different bioceramic coating may affect the bone bonding mechanism."nBiodegredable calcium phosphate coating can be resorbed and be replaced with bone tissues."nHydroxyapatite cause earlier stabilization of dental implant in surrounding bone (biological fixation and"nreduce healing time. Bioglass can protect substrate and provide interfacial attachment to bone.

Porous polymers for repair and replacement of the knee joint meniscus and articular cartilage

NARCIS (Netherlands)

Klompmaker, Jan

1992-01-01

The studies presented here were initiated to answer a variety of questions concerning firstly the repair and replacement of the knee joint meniscus and, secondly, the repair of full-thickness defects of articular cartilage. AIMS OF THE STUDIES I To assess the effect of implantation of a porous

Surgical templates for dental implant positioning; current knowledge and clinical perspectives

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Mohammed Zaheer Kola

2015-01-01

Full Text Available Dental implants have been used in a variety of different forms for many years. Since the mid-20 th century, there has been an increase in interest in the implant process for the replacement of missing teeth. Branemark was one of the initial pioneers who applied scientifically based research techniques to develop an endosseous implant that forms an immobile connection with bone. The need for a dental implant to completely address multiple physical and biological factors imposes tremendous constraints on the surgical and handling protocol. Metallic dental implants have been successfully used for decades, but they have serious shortcomings related to their bony union and the fact that their mechanical properties do not match those of bone. However, anatomic limitation and restorative demands encourage the surgeon to gain precision in planning and surgical positioning of dental implants. Ideal placement of the implant facilitates the establishment of favorable forces on the implants and the prosthetic component as well as ensures an aesthetic outcome. Therefore, it is advisable to establish a logical continuity between the planned restoration and the surgical phases, it is essential to use a transfer device that for sure increases the predictability of success. The surgical guide template is fabricated by a dental technician after the presurgical restorative appointments that primarily include determination of occlusal scheme and implant angulations. Here, authors genuinely attempted to review the evolution and clinical applicability of surgical templates used in the placement of dental implants.

Making 3D implants for conservation and restoration of archaeological glass

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Carmen Díaz-Marín

2017-05-01

Full Text Available This article describes the restoration of a glass bowl from the 16th-17thcentury by creating its three-dimensional (3Dmodel. The final purpose is to work with this model in order to avoid damaging situations that are associated with the manipulation of fragile objects. The gap areas, those corresponding to the missing fragments not found in the excavation, were carried out by constructing digital implants. A restricted area of the 3D model has been duplicated in order to accommodate it to confined intervals of the gap. The final implants were printed with acrylonitrile butadiene styrene (ABS filament. These implants replace the lost areas and give stability back to the item by recovering the original morphology. The result can be compared with the outcome obtained by a traditional process, but differs due to the fact that requires minimum manipulation of the item, so it can contribute to preserve and safeguard the restored object. This is a non-invasive method which is offered as an alternative treatment, where the archaeological object is replaced by its virtual model in the steps of the process after 3D data acquisition. Significant differences have not been found in the 3D printing results obtained with the two types of filaments tested (white and clear.

Autogenous Transplantation for Replacing a Hopeless Tooth.

Science.gov (United States)

Zakershahrak, Mehrsa; Moshari, Amirabbas; Vatanpour, Mehdi; Khalilak, Zohreh; Jalali Ara, Afsoon

2017-01-01

Autogenous tooth transplantation (ATT) is a simple and reasonable choice for replacing the missing teeth when a proper donor tooth is available. This report presents a case of successful ATT of a maxillary right third molar for replacement of mandibular right second molar with a concomitant endodontic-periodontal disease. The mandibular second molar was believed to be hopeless due to a severe damage to coronal tooth structure, inappropriate root canal treatment and apical radiolucency. After extraction of mandibular second molar and maxillary third molar (the donor), the tooth was re-implanted into the extracted socket of second molar site. Root canal therapy was then performed. After 3 years, clinical and radiographic examinations revealed satisfying results, with no signs and symptoms. The patient is asymptomatic and the transplanted tooth is still functional with no signs of marginal periodontal pathosis. Radiographies showed bone regeneration in the site of previous extensive periapical lesion, normal periodontal ligament with no signs of root resorption.

Micro-computerised tomography optimisation for the measurement of bone mineral density around titanium dental implants

International Nuclear Information System (INIS)

Park, C.; Swain, M.; Duncan, W.

2010-01-01

Titanium dental implants (screws) are commonly used to replace missing teeth by forming a biological union with bone ('osseointegration'). Micro-computerised tomography (μCT) may be useful for measuring bone mineral density around dental implants. Major issues arise because of various artefacts that occur with polychromatic X-rays associated bench type instruments that may compromise interpretation of the observations. In this study various approaches to minimise artefacts such as; beam hardening, filtering and edge effects are explored with a homogeneous polymeric material, Teflon, with and without an implant present. The implications of the limitations of using such polychromatic μCT systems to quantify bone mineral density adjacent to the implant are discussed. (author)

Progress in ion implantation equipment for semiconductor manufacturing

International Nuclear Information System (INIS)

Kawai, Tadashi; Naito, Masao

1987-01-01

In the semiconductor device manufacturing industry, ion implantation systems are used to dope semiconductor substrates with impurities that act as donor or acceptor. In an ion implantation system, required impurity ions are generated from an ion source, subjected to mass analysis, accelerated, converged and implanted in semiconductor wafers. High-tension arc tends to cause troubles in these systems, but improvement in design increased the average operation rate of medium-power systems from bout 70 percent to 90 percent during the past 10 years. Freeman type ion sources have replaced most RF ion sources and cold cathode PIG sources, which had been widely used until the early 1970s. Many of the recent ion sources are equipped with a P and As vaporizer to increase the beam intensity. By an increased beam intensity or decreased handling time in combination with an automatic handling system, the throughput has reached 330 wafers per hour for 10 second implantation. The yield has increased due to the development of improved scanning methods, vacuum devices such as cryopump, and processes and apparatus that serve for preventing particles from being contained in micro-devices. Various other improvements have been made to permit efficient production. (Nogami, K.)

Failure of total hip implants: metals and metal release in 52 cases

DEFF Research Database (Denmark)

Jakobsen, Stig Storgaard; Lidén, Carola; Søballe, Kjeld

2014-01-01

Background . The pathogenesis of total joint replacement failure is multifactorial. One hypothesis suggests that corrosion and wear of alloys result in metal ion release, which may then cause sensitization and even implant failure, owing to the acquired immune reactivity. Objectives . To assess c...

Pacemaker replacement in nonagenarians: Procedural safety and long-term follow-up.

Science.gov (United States)

Loirat, Aurélie; Fénéon, Damien; Behaghel, Albin; Behar, Nathalie; Le Helloco, Alain; Mabo, Philippe; Daubert, Jean-Claude; Leclercq, Christophe; Martins, Raphaël P

2015-01-01

The rate of pacemaker implantation is rising. Given that the life expectancy of the population is projected to increase, a large number of elderly patients are likely to be implanted in the future. As pacemaker batteries can last for 8-10years, an increasing number of pacemaker recipients will require replacement of their devices when they become nonagenarians. To analyse the short- and long-term outcomes after device replacement in nonagenarians. Patients aged≥90years referred to a tertiary centre for pacemaker replacement from January 2004 to July 2014 were included retrospectively. Clinical follow-up data were obtained from clinical visits or telephone interviews with patients or their families. The primary clinical endpoint was total mortality. Secondary endpoints included early and delayed procedure-related complications and predictive risk factors for total mortality. Sixty-two patients were included (mean age 93.3±2.9years at time of pacemaker replacement). Mean procedure duration was 35.7±17.2minutes. Mean hospital stay was 2.2±1.1days. One patient died from a perioperative complication. Thirty-seven patients (59.7%) died during a median follow-up of 22.1months (interquartile range, 11.8-39.8months). Survival rates were 84.2% (95% confidence interval [CI] 71.8-91.5%) at 1year, 66.9% (95% CI 51.8-78.2%) at 2years and 22.7% (95% CI 10.6-37.7%) at 5years. Atrial fibrillation (hazard ratio 2.47, 95% CI 1.1-5.6) and non-physiological pacing (i.e. VVI pacing in patients in sinus rhythm) (hazard ratio 2.20, 95% CI 1.0-4.9) were predictors of mortality. Pacemaker replacement in nonagenarians is a safe and straightforward procedure. These data suggest that procedures can be performed securely in this old and frail population, with patients living for a median of 30months afterwards. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Autogenous tooth transplantation: an alternative to replace extracted tooth

Directory of Open Access Journals (Sweden)

David B. Kamadjaja

2015-09-01

Full Text Available Background: The gold standard treatment to replace missing tooth is dental implants, however, in certain cases, such as in young patients its placement is contraindicated. Autogenous tooth transplantation, which has been widely done in Scandinavian countries for many years, may become a good alternative to overcome this problem. Purpose: This article attempted to provide information about the indication, treatment planning, surgical technique and the successful result of autogenous tooth transplantation. Case: A fifteen year old male patient presented with large caries and periapical disease of his lower left first molar, which was partially erupted and the roots was not fully formed in radiograph. Case management: Autogenous tooth transplantation procedure was performed consisting of extraction of #36, odontectomy of #38 followed by its implantation to socket #36 and fixation of the transplanted tooth to the adjacent teeth. Post operative evaluation was done on regular basis within 18 months period. There was no complaint, the tooth was clinically stable and no evidence of periodontal problem. Serial radiographs showed healing of alveolar bone and periodontal tissue, and the complete root formation was evident by 18 months post operatively. Conclusion: Autogenous tooth transplantation is a potential alternative to replace extracted tooth. Provided that the case be properly planned and operation carefully performed, successful result of this treatment can be achieved.

PRIMARY ENDOPROSTHETIC REPLACEMENT OF THE ANOPHTHALMIC ORBIT IN PATIENTS WITH UVEAL MELANOMA: SIX-YEAR FOLLOW-UP RESULTS

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A. A. Yarovoy

2012-01-01

Full Text Available A locomotor stump was formed in 36 patients (28 women and 8 men, by implanting an endoprosthesis for enucleation of the eyeball with uveal melanoma (UM. The indication for endoprosthesis implantation was no signs of extrabulbar growth. A modified 17–19 mm silicone implant covered with strips from a dura mater graft and medical mesh fabric was used as an orbital implant. The follow-up was 3 to 72 months (mean 32.5 months. All the patients achieved a satisfactory cosmetic effect. None patient was found to have a recurrent orbital tumor. Out of the complications, anterior implant surface denudation was noted in 4 patients. Two patients developed metastases. The absence of recurrent orbital UM at a 6-year follow-up enables primary endoprosthetic replacement of the orbit for UM to be regarded as a safe and reasonable method for patient cosmetic rehabilitation. 

Neck Pain One Week after Pacemaker Generator Replacement.

Science.gov (United States)

Graham, Ross F; Wightman, John M

2015-07-01

The incidence of cardiac pacemaker implantation has risen markedly in the past three decades, making awareness of possible postprocedural complications critical to the emergency physician. This case is the first documented instance of internal jugular (IJ) deep vein thrombosis (DVT) from an uncomplicated pacemaker generator replacement. A patient presented to an Emergency Department with a 2-day history of mild left temporal headache migrating to his left neck. The patient did not volunteer this information, but review of systems revealed a temporary transvenous pacemaker inserted through the right IJ vein 1 week previously during a routine exchange of a left-sided cardiac pacemaker generator. Manipulation of the existing pacemaker wires entering the left subclavian vein was minimal. Computed tomographic angiography of the neck demonstrated near-complete thrombotic occlusion of the entire length of his left IJ vein. This required hospital admission for observation and treatment with anticoagulation. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: DVT, with thrombotic extension into adjacent vessels anywhere along the course of pacemaker wires, should be considered by the emergency provider in the evaluation of head, neck, or upper extremity symptoms after recent or remote implantation or manipulation of a transvenous cardiac pacemaker, including generator replacement. Failure to identify and treat appropriately could result in significant morbidity and mortality from airway edema, septic thrombophlebitis, superior vena cava syndrome, superior sagittal sinus thrombosis, or pulmonary embolism. Published by Elsevier Inc.

Hemolytic anemia caused by kinking of dacron grafts implanted in ...

African Journals Online (AJOL)

Background: Hemolytic anemia caused by a kinked Dacron graft is a rare complication after repair of acute aortic dissection. We present a case of hemolytic anemia due to kinking of previously implanted Dacron graft for ascending aorta dissection treated by surgery and replaced with new Dacron. Case Details: We report a ...

Changing of the guard: reducing infection when replacing neural pacemakers.

Science.gov (United States)

Pepper, Joshua; Meliak, Lara; Akram, Harith; Hyam, Jonathan; Milabo, Catherine; Candelario, Joseph; Foltynie, Thomas; Limousin, Patricia; Curtis, Carmel; Hariz, Marwan; Zrinzo, Ludvic

2017-04-01

OBJECTIVE Infection of deep brain stimulation (DBS) hardware has a significant impact on patient morbidity. Previous experience suggests that infection rates appear to be higher after implantable pulse generator (IPG) replacement surgery than after the de novo DBS procedure. In this study the authors examine the effect of a change in practice during DBS IPG replacements at their institution. METHODS Starting in January 2012, patient screening for methicillin-resistant Staphylococcus aureus (MRSA) and, and where necessary, eradication was performed prior to elective DBS IPG change. Moreover, topical vancomycin was placed in the IPG pocket during surgery. The authors then prospectively examined the infection rate in patients undergoing DBS IPG replacement at their center over a 3-year period with at least 9 months of follow-up. RESULTS The total incidence of infection in this prospective consecutive series of 101 IPG replacement procedures was 0%, with a mean follow-up duration of 24 ± 11 months. This was significantly lower than the authors' previously published historical control group, prior to implementing the change in practice, where the infection rate for IPG replacement was 8.5% (8/94 procedures; p = 0.003). CONCLUSIONS This study suggests that a change in clinical practice can significantly lower infection rates in patients undergoing DBS IPG replacement. These simple measures can minimize unnecessary surgery, loss of benefit from chronic stimulation, and costly hardware replacement, further improving the cost efficacy of DBS therapies.

When Not to Go SOLO? Contraindications Based on Implant Experience.

Science.gov (United States)

Wollersheim, Laurens W; Li, Wilson W; Kaya, Abdullah; van Boven, Wim J; van der Meulen, Jan; de Mol, Bas A

2016-11-01

Because of the design and specific implantation technique of the stentless Freedom SOLO bioprosthesis, patient selection is crucial. The aim of the study was to discuss the contraindications to this prosthesis based on the authors' implant experience. Between April 2005 and February 2015, one surgeon at the authors' center performed 292 aortic valve replacements using a bioprosthesis, with the initial intention of implanting a SOLO valve in every patient. A search was conducted for all of these patients and data collected on whether a SOLO valve was used, or not. A SOLO valve was implanted in 238 patients (82%), and a stented bioprosthesis in 54 (18%). The predominant reasons not to implant a SOLO valve were asymmetric commissures (26%) and a large aortic annulus (24%). Only one patient had structural valve deterioration, and none of the patients had to undergo reoperation because of aortic valve insufficiency or paravalvular leakage. Asymmetric commissures, large aortic annulus (>27 mm), calcified aortic sinuses, dilated sinotubular junction, aberrant location of coronary ostia and whenever the stent of a stented bioprosthesis is useful, were contraindications to implant a SOLO valve. When these contraindications were taken into account, a very good durability could be achieved with the SOLO valve during mid-term follow up.

Mechanical Behavior of Polymer Nano Bio Composite for Orthopedic Implants

Science.gov (United States)

Marimuthu, K., Dr.; Rajan, Sankar

2018-04-01

The bio-based polymer composites have been the focus of many scientific and research projects, as well as many commercial programs. In recent years, scientists and engineers have been working together to use the inherent strength and performance of the new class of bio-based composites which is compactable with human body and can act as a substitute for living cells. In this stage the polymer composites also stepped into human bone implants as a replacement for metallic implants which was problems like corrosion resistance and high cost. The polymer composite have the advantage that it can be molded to the required shape, the polymers have high corrosion resistance, less weight and low cost. The aim of this research is to develop and analyze the suitable bio compactable polymer composite for human implants. The nano particles reinforced polymer composites provides good mechanical properties and shows good tribological properties especially in the total hip and knee replacements. The graphene oxide powders are bio compactable and acts as anti biotic. GO nano powder where reinforced into High-density polyethylene in various weight percentage of 0.5% to 2%. The performance of GO nano powder shows better tribological properties. The material produced does not cause any pollution to the environment and at the same time it can be bio compactable and sustainable. The product will act environmentally friendly.

Survival of Implants in Immediate Extraction Sockets of Anterior Teeth: Early Clinical Results.

Science.gov (United States)

Sabir, Mohammad; Alam, Mohammad Nazish

2015-06-01

The aims and objectives of this study were placement of implants in freshly extracted sockets of anterior teeth and to evaluate the implant stability, peri-implant radiolucency and gingival inflammation around implant over a short period of 30 months. A total of 12 patients (8 male and 4 female), ranging in the age from 20 to 50 years, from March 2007 to June 2007, were evaluated for immediate implant placement into 22 fresh extraction sockets. Only maxillary and mandibular anterior teeth/roots (central incisors, lateral incisors and canines) were considered for replacement with implants. One piece implant with integrated abutment and integrated surface, non-submerged, threaded and tapered at apical 5 mm, sand-blasted and acid etched surfaced implants (HI-TEC TRX-OP Implants of Life Care Company) were used. The mobility was not present in any of the implants at all the follow up visits. There were 2 implants at 6 month, 1 implant at 12 month, 1 implant at 18 month visits, showing peri-implant radiolucency at some sites at bone to implant contact site. Severe gingival inflammation was not observed in any of the implant site. At every follow-up visit, every implant met the criteria of success and none was found to be failed over a 30 months duration i.e. 100% success rate was achieved by implants in immediate extraction socket. The success rate of implant survival in this study was found 100%. These implants have fulfilled all the criteria of implant success and based on the defined criteria, the success rate of implants placed in immediate extraction sockets of anterior teeth compared favorably with the conventional implants. The early results of the present study showed that high survival rates with the implants in immediate extraction sockets can be achieved.

Autogenous tooth transplantation for replacing a lost tooth: case reports

Directory of Open Access Journals (Sweden)

Ji-Youn Kang

2013-02-01

Full Text Available The autogenous tooth transplantation is an alternative treatment replacing a missing tooth when a suitable donor tooth is available. It is also a successful treatment option to save significant amount of time and cost comparing implants or conventional prosthetics. These cases, which required single tooth extraction due to deep caries and severe periodontal disease, could have good results by transplanting non-functional but sound donor tooth to the extraction site.

Failure of Emperion modular femoral stem with implant analysis

Directory of Open Access Journals (Sweden)

Benjamin M. Stronach, MD, MS

2016-03-01

Full Text Available Modularity in total hip arthroplasty provides multiple benefits to the surgeon in restoring the appropriate alignment and position to a previously damaged hip joint. The vast majority of modern implants incorporate modularity into their design with some implants having multiple modular interfaces. There is the potential for failure at modular junctions because of fretting and crevice corrosion in combination with mechanical loading. This case report details the failure of an Emperion (Smith and Nephew, Memphis, TN femoral stem in a 67-year-old male patient 6 years after total hip replacement. Analysis of the implant revealed mechanically assisted crevice corrosion that likely accelerated fatigue crack initiation in the hip stem. The benefits of modularity come with the potential drawback of a combination of fretting and crevice corrosion at the modular junction, which may accelerate fatigue, crack initiation and ultimately reduce the hip longevity.

Analysis of Mitral Valve Replacement Outcomes is Enhanced by Meaningful Clinical Use of Electronic Health Records

Science.gov (United States)

Chen, John C; Pfeffer, Thomas; Johnstone, Shelley; Chen, Yuexin; Kiley, Mary-Lou; Richter, Richard; Lee, Hon

2013-01-01

Objective: Cardiac surgical mortality has improved during the last decade despite the aging of the population. An integrated US health plan developed a heart valve registry to track outcomes and complications of heart valve operations. This database was used for longitudinal evaluation of mitral valve (MV) outcomes from 1999 to 2008 at four affiliated hospitals. Methods: We identified 3130 patients in the Apollo database who underwent 3180 initial MV procedures. Internal administrative and Social Security Administration databases were merged to determine survival rates. Electronic health records were searched to ascertain demographics, comorbidities, and postoperative complications. Cox regression was used to evaluate mean survival and identify risk factors. Results: The procedures included 1160 mechanical valve replacements, 1159 tissue valve replacements, and 861 annuloplasties. The mean age of patients undergoing these procedures was 58 ± 11 years, 69 ± 12 years, and 62 ± 12 years, respectively. Mean survival was 8.9 ± 0.1 years for mechanical valve replacement, 7.0 ± 0.1 years for tissue valve replacement, and 7.7 ± 0.1 years for annuloplasty. Early in the study, there was a preference for implanting mechanical MVs. Beginning in 2003, more patients received tissue valve replacements rather than mechanical valves. Over time, there was an increasing trend of annuloplasty. Cox regression analysis identified the following risk factors for increased ten-year mortality: tissue valve implantation; advanced age; female sex; nonelective, nonisolated procedure; diabetes; postoperative use of banked blood products; previous cardiovascular intervention; dialysis; and longer perfusion time. Hospital location, reoperation, preoperative anticoagulation, and cardiogenic shock were not statistically significant risk factors. Conclusions: When controlling for other risk factors, we observed a lower long-term survival rate for tissue valve replacement compared with

In-vivo evaluation of the kinematic behavior of an artificial medial meniscus implant: A pilot study using open-MRI.

Science.gov (United States)

De Coninck, Tineke; Elsner, Jonathan J; Linder-Ganz, Eran; Cromheecke, Michiel; Shemesh, Maoz; Huysse, Wouter; Verdonk, René; Verstraete, Koenraad; Verdonk, Peter

2014-09-01

In this pilot study we wanted to evaluate the kinematics of a knee implanted with an artificial polycarbonate-urethane meniscus device, designed for medial meniscus replacement. The static kinematic behavior of the implant was compared to the natural medial meniscus of the non-operated knee. A second goal was to evaluate the motion pattern, the radial displacement and the deformation of the meniscal implant. Three patients with a polycarbonate-urethane implant were included in this prospective study. An open-MRI was used to track the location of the implant during static weight-bearing conditions, within a range of motion of 0° to 120° knee flexion. Knee kinematics were evaluated by measuring the tibiofemoral contact points and femoral roll-back. Meniscus measurements (both natural and artificial) included anterior-posterior meniscal movement, radial displacement, and meniscal height. No difference (P>0.05) was demonstrated in femoral roll-back and tibiofemoral contact points during knee flexion between the implanted and the non-operated knees. Meniscal measurements showed no significant difference in radial displacement and meniscal height (P>0.05) at all flexion angles, in both the implanted and non-operated knees. A significant difference (P ≤ 0.05) in anterior-posterior movement during flexion was observed between the two groups. In this pilot study, the artificial polycarbonate-urethane implant, indicated for medial meniscus replacement, had no influence on femoral roll-back and tibiofemoral contact points, thus suggesting that the joint maintains its static kinematic properties after implantation. Radial displacement and meniscal height were not different, but anterior-posterior movement was slightly different between the implant and the normal meniscus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Battery longevity in cardiac resynchronization therapy implantable cardioverter defibrillators.

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Alam, Mian Bilal; Munir, Muhammad Bilal; Rattan, Rohit; Flanigan, Susan; Adelstein, Evan; Jain, Sandeep; Saba, Samir

2014-02-01

Cardiac resynchronization therapy (CRT) implantable cardioverter defibrillators (ICDs) deliver high burden ventricular pacing to heart failure patients, which has a significant effect on battery longevity. The aim of this study was to investigate whether battery longevity is comparable for CRT-ICDs from different manufacturers in a contemporary cohort of patients. All the CRT-ICDs implanted at our institution from 1 January 2008 to 31 December 2010 were included in this analysis. Baseline demographic and clinical data were collected on all patients using the electronic medical record. Detailed device information was collected on all patients from scanned device printouts obtained during routine follow-up. The primary endpoint was device replacement for battery reaching the elective replacement indicator (ERI). A total of 646 patients (age 69 ± 13 years), implanted with CRT-ICDs (Boston Scientific 173, Medtronic 416, and St Jude Medical 57) were included in this analysis. During 2.7 ± 1.5 years follow-up, 113 (17%) devices had reached ERI (Boston scientific 4%, Medtronic 25%, and St Jude Medical 7%, P battery was significantly worse for Medtronic devices compared with devices from other manufacturers (94% for Boston scientific, 67% for Medtronic, and 92% for St Jude Medical, P battery longevity by manufacturer was independent of pacing burden, lead parameters, and burden of ICD therapy. There are significant discrepancies in CRT-ICD battery longevity by manufacturer. These data have important implications on clinical practice and patient outcomes.

Highly antibacterial UHMWPE surfaces by implantation of titanium ions

Energy Technology Data Exchange (ETDEWEB)

Delle Side, D., E-mail: domenico.delleside@le.infn.it [LEAS, Dipartimento di Matematica e Fisica “Ennio de Giorgi”, Università del Salento, Lecce (Italy); Istituto Nazionale di Fisica Nucleare – Sezione di Lecce, Lecce (Italy); Nassisi, V.; Giuffreda, E.; Velardi, L. [LEAS, Dipartimento di Matematica e Fisica “Ennio de Giorgi”, Università del Salento, Lecce (Italy); Istituto Nazionale di Fisica Nucleare – Sezione di Lecce, Lecce (Italy); Alifano, P.; Talà, A.; Tredici, S.M. [Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, Lecce (Italy)

2014-07-15

The spreading of pathogens represents a serious threat for human beings. Consequently, efficient antimicrobial surfaces are needed in order to reduce risks of contracting severe diseases. In this work we present the first evidences of a new technique to obtain a highly antibacterial Ultra High Molecular Weight Polyethylene (UHMWPE) based on a non-stoichiometric titanium oxide coating, visible-light responsive, obtained through ion implantation.

Highly antibacterial UHMWPE surfaces by implantation of titanium ions

Science.gov (United States)

Delle Side, D.; Nassisi, V.; Giuffreda, E.; Velardi, L.; Alifano, P.; Talà, A.; Tredici, S. M.

2014-07-01

The spreading of pathogens represents a serious threat for human beings. Consequently, efficient antimicrobial surfaces are needed in order to reduce risks of contracting severe diseases. In this work we present the first evidences of a new technique to obtain a highly antibacterial Ultra High Molecular Weight Polyethylene (UHMWPE) based on a non-stoichiometric titanium oxide coating, visible-light responsive, obtained through ion implantation.

Methods to Improve Osseointegration of Dental Implants in Low Quality (Type-IV Bone: An Overview

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Hamdan S. Alghamdi

2018-01-01

Full Text Available Nowadays, dental implants have become more common treatment for replacing missing teeth and aim to improve chewing efficiency, physical health, and esthetics. The favorable clinical performance of dental implants has been attributed to their firm osseointegration, as introduced by Brånemark in 1965. Although the survival rate of dental implants over a 10-year observation has been reported to be higher than 90% in totally edentulous jaws, the clinical outcome of implant treatment is challenged in compromised (bone conditions, as are frequently present in elderly people. The biomechanical characteristics of bone in aged patients do not offer proper stability to implants, being similar to type-IV bone (Lekholm & Zarb classification, in which a decreased clinical fixation of implants has been clearly demonstrated. However, the search for improved osseointegration has continued forward for the new evolution of modern dental implants. This represents a continuum of developments spanning more than 20 years of research on implant related-factors including surgical techniques, implant design, and surface properties. The methods to enhance osseointegration of dental implants in low quality (type-IV bone are described in a general manner in this review.

Methods to Improve Osseointegration of Dental Implants in Low Quality (Type-IV) Bone: An Overview.

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Alghamdi, Hamdan S

2018-01-13

Nowadays, dental implants have become more common treatment for replacing missing teeth and aim to improve chewing efficiency, physical health, and esthetics. The favorable clinical performance of dental implants has been attributed to their firm osseointegration, as introduced by Brånemark in 1965. Although the survival rate of dental implants over a 10-year observation has been reported to be higher than 90% in totally edentulous jaws, the clinical outcome of implant treatment is challenged in compromised (bone) conditions, as are frequently present in elderly people. The biomechanical characteristics of bone in aged patients do not offer proper stability to implants, being similar to type-IV bone (Lekholm & Zarb classification), in which a decreased clinical fixation of implants has been clearly demonstrated. However, the search for improved osseointegration has continued forward for the new evolution of modern dental implants. This represents a continuum of developments spanning more than 20 years of research on implant related-factors including surgical techniques, implant design, and surface properties. The methods to enhance osseointegration of dental implants in low quality (type-IV) bone are described in a general manner in this review.

Tubing erosion of an inflatable penile prosthesis long after implantation.

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Morales, Alvaro

2014-06-01

Erosion through skin of connecting tubing of an inflatable penile prosthesis (IPP) has not been previously reported. The aim of this study was to present a case of tubing erosion, review the pertinent literature, and discuss the possible causes and management options, including preservation of the device and its components. A 42-year-old male failing to respond to medical treatment for erectile dysfunction underwent insertion of an AMS 700 IPP in 1986. Six years later, a revision was necessary because of a leak in the right cylinder and 4 years after, the pump was replaced. Fourteen years after the original implant, he presented with a portion of the tube connecting the pump to the right cylinder eroding through the skin. There was no infection. The skin area involved was resected and the original pump and tubing were buried in a new scrotal pocket after thorough irrigation. The IPP remained in place, allowing vaginal penetration and without infection for another 11 years. Three years later, it was de-functionalized, converted into a fixed volume device. It eventually was replaced 25 years after originally implanted with a semirigid prosthesis because it did not provide sufficient rigidity and because of concerns about the presence of "screws" detected during pelvic imaging. Mechanical failures in the early IPP models, as illustrated in this case, were expected. However, the long survival of the device is remarkable. Erosion of the connecting tubing through the skin is unique and, under exceptional circumstances, may be managed conservatively without replacing components of the IPP. Clinicians unfamiliar with procedures involving inflatable devices need to be aware of "foreign bodies" visible in radiological examinations in men who have had revisions of an IPP. Morales A. Tubing erosion of an inflatable penile prosthesis long after implantation. Sex Med 2014;2:103-106.

Stock Versus CAD/CAM Customized Zirconia Implant Abutments – Clinical and Patient‐Based Outcomes in a Randomized Controlled Clinical Trial

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Meijer, Henny J.A.; Kerdijk, Wouter; Raghoebar, Gerry M.; Cune, Marco

2016-01-01

Abstract Background Single‐tooth replacement often requires a prefabricated dental implant and a customized crown. The benefits of individualization of the abutment remain unclear. Purpose This randomized controlled clinical trial aims to study potential benefits of individualization of zirconia implant abutments with respect to preservation of marginal bone level and several clinical and patient‐based outcome measures. Material and Methods Fifty participants with a missing premolar were included and randomly assigned to standard (ZirDesign, DentsplySirona Implants, Mölndal, Sweden) or computer aided design/computer aided manufacturing (CAD/CAM) customized (Atlantis, DentsplySirona Implants, Mölndal, Sweden) zirconia abutment therapy. Peri‐implant bone level (primary outcome), Plaque‐index, calculus formation, bleeding on probing, gingiva index, probing pocket depth, recession, appearance of soft tissues and patients' contentment were assessed shortly after placement and one year later. Results No implants were lost and no complications related to the abutments were observed. Statistically significant differences between stock and CAD/CAM customized zirconia abutments could not be demonstrated for any of the operationalized variables. Conclusion The use of a CAD/CAM customized zirconia abutment in single tooth replacement of a premolar is not associated with an improvement in clinical performance or patients' contentment when compared to the use of a stock zirconia abutment. PMID:27476829

Interventions for replacing missing teeth: Antibiotics in dental implant placement to prevent complications: Evidence summary of Cochrane review.

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Jayaraman, Srinivasan

2015-01-01

The failure of dental implant can occurs at the preoperative planning stage, at the surgical stage, and at the postoperative stage. The success of this treatment can be increased if the clinical implant practice guidelines are prepared based on the recommendations from the highest level of research evidence (i.e.,) from systematic review of randomized controlled trials (RCTs) with meta-analysis. The Cochrane reviews of interventions are basically systematic reviews of RCTs with meta-analysis but follow a systematic methodological approach following the guidelines from Cochrane handbook for Systematic Reviews of Intervention. They give the current best evidence as they are updated every 2 years which is being the minimum period for an update. This evidence summary recommends the use of antibiotics, single dose of 2 g of amoxicillin 1 h prior to implant surgery to prevent implant failure, based on the body of evidence from the Cochrane review that was first published in 2003, 2008, and then updated twice in 2010 and 2013. The included studies are not from our population for the research question asked in this updated Cochrane review; hence, the need to do primary research in our population to support the available evidence is mandatory.

Factors associated with dental implant survival: a 4-year retrospective analysis.

Science.gov (United States)

Zupnik, Jamie; Kim, Soo-woo; Ravens, Daniel; Karimbux, Nadeem; Guze, Kevin

2011-10-01

Dental implants are a predictable treatment option for replacing missing teeth and have strong survival and success outcomes. However, previous research showed a wide array of potential risk factors that may have contributed to dental implant failures. The objectives of this study are to study if implant survival rates were affected by known risk factors and risk indicators that may have contributed to implant failures. The secondary outcome measures were whether the level of expertise of the periodontal residents affected success rates and how the rate of implant success at the Harvard School of Dental Medicine (HSDM) compared to published standards. A retrospective chart review of patients at the HSDM who had one of two types of rough-surface implants (group A or B) placed by periodontology residents from 2003 to 2006 was performed. Demographic, health, and implant data were collected and analyzed by multimodel analyses to determine failure rates and any factors that may have increased the likelihood of an implant failure. The study cohort included 341 dental implants. The odds ratio for an implant failure was most clearly elevated for diabetes (2.59 implant surface group B (7.84), and male groups (4.01). There was no significant difference regarding the resident experience. The success rate for HSDM periodontology residents was 96.48% during the 4-year study period. This study demonstrates that implant success rates at HSDM fell within accepted published standards, confirmed previously identified risk factors for a failure, and potentially suggested that other acknowledged risk factors could be controlled for. Furthermore, the level of experience of the periodontology resident did not have an impact on survival outcomes.

Analysis of metal ion release from biomedical implants

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Ivana Dimić

2013-06-01

Full Text Available Metallic biomaterials are commonly used for fixation or replacement of damaged bones in the human body due to their good combination of mechanical properties. The disadvantage of metals as implant materials is their susceptibility to corrosion and metal ion release, which can cause serious health problems. In certain concentrations metals and metal ions are toxic and their presence can cause diverse inflammatory reactions, genetic mutations or even cancer. In this paper, different approaches to metal ion release examination, from biometallic materials sample preparation to research results interpretation, will be presented. An overview of the analytical techniques, used for determination of the type and concentration of released ions from implants in simulated biofluids, is also given in the paper.

Osseointegrated silicone finger prosthesis using dental implants: a renovated technique.

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Vinnakota, Dileep Nag; Sankar, V Vijay; Chirumamilla, Naveen; Reddy, V Vamsikrishna

2014-11-01

In clinical practice, we come across patients with traumatically amputated or congenitally missing partial or complete fingers that can be restored using microsurgical replantation or transplantation procedures. However, in some cases this might not be possible due to systemic or local factors and the lost or missing part has to be replaced prosthetically to offer psychological and functional wellbeing. These prostheses can be constructed with various materials like acrylics or silicone retained with the help of auxiliary aids. However, these prostheses cause some hindrance in performing functions like writing, typing, etc. The aim of the present trial was to ameliorate the existing design of implant supported finger prosthesis. Distal phalange of middle finger replaced with implant supported silicone finger prosthesis is modified by utilizing a metal framework to support silicone material to improve rigidity while working. We could achieve a good function, esthetics and tactile sensibility with this modified design. Whenever, feasible this design can improve the performance and patients feel a deep sense of satisfaction and improved self-esteem with this modified prosthesis.

The Need for an Implant Identification Card at Airport Security Check.

Science.gov (United States)

Ali, Erden; Kosuge, Dennis; MacDowell, Andrew

2017-06-01

Joint replacement surgery is having an increasing demand as national healthcare systems confront an ever ageing population. Surgical complications associated with lower limb arthroplasty are well known but less investigation has been performed examining its effect on air travel, more specifically, unwanted and significant inconvenience caused to travelers going through airport security. In lower limb arthroplasty clinics, 50 patients who met our selection criteria were given questionnaires. Ten airport security officers from 4 international airports (London Stansted, London Gatwick, London Heathrow, and Amsterdam Schiphol International Airport) were also given a separate questionnaire. The opinion of the Civil Aviation Authority was also sought. All 50 patients (mean age, 70.4 years; range, 55 to 84 years) who were presenting in lower limb arthroplasty clinics and who met our selection criteria volunteered to enter the study. Twenty-eight of these patients were female (mean age, 69.1 years; range, 55 to 84 years) and 22 were male (mean age, 71.2 years; range, 58 to 81 years). Of the patients, 14% stated that their joint replacements did not set off the airport security alarm. Responses were received from 10 airport security officers as well. Six airport security officers were male and 4 were female. All of the airport officers were aware of some form of implant identification card with 90% stating that these were useful to them at airport security. Eight-four percent of the patients stated that an implant identification card outlining what joint replacement they possessed and when this had been done would be very useful. Sixteen percent of the patients did not think a card would be beneficial since all of them had set off the airport alarm system only once or less in their lifetime. It is the opinion of airport security officers and patients that joint replacement implant identification cards streamline airport security checks and decrease the need for more

The Effect of Ag and Ag+N Ion Implantation on Cell Attachment Properties

International Nuclear Information System (INIS)

Urkac, Emel Sokullu; Oztarhan, Ahmet; Gurhan, Ismet Deliloglu; Iz, Sultan Gulce; Tihminlioglu, Funda; Oks, Efim; Nikolaev, Alexey; Ila, Daryush

2009-01-01

Implanted biomedical prosthetic devices are intended to perform safely, reliably and effectively in the human body thus the materials used for orthopedic devices should have good biocompatibility. Ultra High Molecular Weight Poly Ethylene (UHMWPE) has been commonly used for total hip joint replacement because of its very good properties. In this work, UHMWPE samples were Ag and Ag+N ion implanted by using the Metal-Vapor Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with a fluency of 1017 ion/cm2 and extraction voltage of 30 kV. Rutherford Backscattering Spectrometry (RBS) was used for surface studies. RBS showed the presence of Ag and N on the surface. Cell attachment properties investigated with model cell lines (L929 mouse fibroblasts) to demonstrate that the effect of Ag and Ag+N ion implantation can favorably influence the surface of UHMWPE for biomedical applications. Scanning electron microscopy (SEM) was used to demonstrate the cell attachment on the surface. Study has shown that Ag+N ion implantation represents more effective cell attachment properties on the UHMWPE surfaces.

Do modern total knee replacements offer better value for money? A health economic analysis.

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Hamilton, David F; Clement, Nicholas D; Burnett, Richard; Patton, James T; Moran, Mathew; Howie, Colin R; Simpson, A H R W; Gaston, Paul

2013-11-01

Cost effectiveness is an increasingly important factor in today's healthcare environment, and selection of arthroplasty implant is not exempt from such concerns. Quality adjusted life years (QALYs) are the typical tool for this type of evaluation. Using this methodology, joint arthroplasty has been shown to be cost effective; however, studies directly comparing differing prostheses are lacking. Data was gathered in a single-centre prospective double-blind randomised controlled trial comparing the outcome of modern and traditional knee implants, using the Short Form 6 dimensional (SF-6D) score and quality adjusted life year (QALY) methodology. There was significant improvement in the SF-6D score for both groups at one year (p traditional design at one year (0.141 versus 0.143, p = 0.94). This difference resulted in the modern implant costing £298 less per QALY at one year. This study demonstrates that modern implant technology does not influence the cost-effectiveness of TKA using the SF-6D and QALY methodology. This type of analysis however assesses health status, and is not sensitive to joint specific function. Evolutionary design changes in implant technology are thus unlikely to influence QALY analysis following joint replacement, which has important implications for implant procurement.

Impact of heavy smoking on the clinical, microbiological and immunological parameters of patients with dental implants: a prospective cross-sectional study.

Science.gov (United States)

Ata-Ali, Javier; Flichy-Fernández, Antonio Juan; Alegre-Domingo, Teresa; Ata-Ali, Fadi; Peñarrocha-Diago, Miguel

2016-11-01

The aim of the present study was to investigate how heavy smoking influences the clinical, microbiological, and host-response characteristics in peri-implant sulcus fluid of patients with healthy dental implants. A total of 29 individuals with 74 dental implants were included in the present study; 20 implants were in heavy smokers and 54 were in non-smokers. The modified gingival index, modified plaque index, and probing pocket depth were evaluated. Periodontopathogenic bacteria Tannerella forsythia, Treponema denticola, and Porphyromonas gingivalis were evaluated, together with the total bacterial load. Peri-implant sulcus fluid samples were analyzed for the quantification of interleukin-8, interleukin-1β, interleukin-6, interleukin-10, and tumor necrosis factor-α. No significant differences in the clinical parameters evaluated were found between the groups, although smokers had poorer peri-implant parameters. Among the smokers, subgingival microbiota was composed of a greater number of periodontal pathogens; these differences were not statistically significant. Smokers showed a greater expression of interleukin-1β, interleukin-6, interleukin-10, and tumor necrosis factor-α, but interleukin-8 was slightly higher among non-smokers, but not significantly. Although smokers presented deeper probing depths, bleeding on probing, and peri-implant microbiota composed of a greater number of periodontal pathogens than in non-smoking patients, these data did not show significant differences. In the present study, and in relation to the samples analyzed, smoking alone did not influence the immunological and microbiological parameters in dental implants with healthy peri-implant tissues. Further studies with larger samples are required to better evaluate the influence of smoking on dental implants. © 2015 Wiley Publishing Asia Pty Ltd.

Fracture strength of zirconia implant abutments on narrow diameter implants with internal and external implant abutment connections: A study on the titanium resin base concept.

Science.gov (United States)

Sailer, Irena; Asgeirsson, Asgeir G; Thoma, Daniel S; Fehmer, Vincent; Aspelund, Thor; Özcan, Mutlu; Pjetursson, Bjarni E

2018-04-01

There is limited knowledge regarding the strength of zirconia abutments with internal and external implant abutment connections and zirconia abutments supported by a titanium resin base (Variobase, Straumann) for narrow diameter implants. To compare the fracture strength of narrow diameter abutments with different types of implant abutment connections after chewing simulation. Hundred and twenty identical customized abutments with different materials and implant abutment connections were fabricated for five groups: 1-piece zirconia abutment with internal connection (T1, Cares-abutment-Straumann BL-NC implant, Straumann Switzerland), 1-piece zirconia abutment with external hex connection (T2, Procera abutment-Branemark NP implant, Nobel Biocare, Sweden), 2-piece zirconia abutments with metallic insert for internal connection (T3, Procera abutment-Replace NP implant, Nobel Biocare), 2-piece zirconia abutment on titanium resin base (T4, LavaPlus abutment-VarioBase-Straumann BL-NC implant, 3M ESPE, Germany) and 1-piece titanium abutment with internal connection (C, Cares-abutment-Straumann BL-NC implant, Straumann, Switzerland). All implants had a narrow diameter ranging from 3.3 to 3.5 mm. Sixty un-restored abutments and 60 abutments restored with glass-ceramic crowns were tested. Mean bending moments were compared using ANOVA with p-values adjusted for multiple comparisons using Tukey's procedure. The mean bending moments were 521 ± 33 Ncm (T4), 404 ± 36 Ncm (C), 311 ± 106 Ncm (T1) 265 ± 22 Ncm (T3) and 225 ± 29 (T2) for un-restored abutments and 278 ± 84 Ncm (T4), 302 ± 170 Ncm (C), 190 ± 55 Ncm (T1) 80 ± 102 Ncm (T3) and 125 ± 57 (T2) for restored abutments. For un-restored abutments, C and T4 had similar mean bending moments, significantly higher than those of the three other groups (p internal connection had higher bending moments than zirconia abutments with external connection (T2) (p internal connected zirconia

Wear Behavior of an Unstable Knee: Stabilization via Implant Design?

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Jörn Reinders

2014-01-01

Full Text Available Background. Wear-related failures and instabilities are frequent failure mechanisms of total knee replacements. High-conforming designs may provide additional stability for the joint. This study analyzes the effects of a ligamentous insufficiency on the stability and the wear behavior of a high-conforming knee design. Methods. Two simulator wear tests were performed on a high-conforming total knee replacement design. In the first, a ligamentous-stable knee replacement with a sacrificed anterior cruciate ligament was simulated. In the second, a ligamentous-unstable knee with additionally insufficient posterior cruciate ligament and medial collateral ligament was simulated. Wear was determined gravimetrically and wear particles were analyzed. Implant kinematics was recorded during simulation. Results. Significantly higher wear rates (P≤0.001 were observed for the unstable knee (14.58±0.56 mg/106 cycles compared to the stable knee (7.97 ± 0.87 mg/106 cycles. A higher number of wear particles with only small differences in wear particle characteristics were observed. Under unstable knee conditions, kinematics increased significantly for translations and rotations (P≤0.01. This increase was mainly attributed to higher tibial posterior translation and internal rotations. Conclusion. Higher kinematics under unstable test conditions is a result of insufficient stabilization via implant design. Due to the higher kinematics, increased wear was observed in this study.

Feasible introgression of an anti-pathogen transgene into an urban mosquito population without using gene-drive.

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Kenichi W Okamoto

2014-07-01

Full Text Available Introgressing anti-pathogen constructs into wild vector populations could reduce disease transmission. It is generally assumed that such introgression would require linking an anti-pathogen gene with a selfish genetic element or similar technologies. Yet none of the proposed transgenic anti-pathogen gene-drive mechanisms are likely to be implemented as public health measures in the near future. Thus, much attention now focuses instead on transgenic strategies aimed at mosquito population suppression, an approach generally perceived to be practical. By contrast, aiming to replace vector competent mosquito populations with vector incompetent populations by releasing mosquitoes carrying a single anti-pathogen gene without a gene-drive mechanism is widely considered impractical.Here we use Skeeter Buster, a previously published stochastic, spatially explicit model of Aedes aegypti to investigate whether a number of approaches for releasing mosquitoes with only an anti-pathogen construct would be efficient and effective in the tropical city of Iquitos, Peru. To assess the performance of such releases using realistic release numbers, we compare the transient and long-term effects of this strategy with two other genetic control strategies that have been developed in Ae. aegypti: release of a strain with female-specific lethality, and a strain with both female-specific lethality and an anti-pathogen gene. We find that releasing mosquitoes carrying only an anti-pathogen construct can substantially decrease vector competence of a natural population, even at release ratios well below that required for the two currently feasible alternatives that rely on population reduction. Finally, although current genetic control strategies based on population reduction are compromised by immigration of wild-type mosquitoes, releasing mosquitoes carrying only an anti-pathogen gene is considerably more robust to such immigration.Contrary to the widely held view that

Coherent Synchrotron-Based Micro-Imaging Employed for Studies of Micro-Gap Formation in Dental Implants

International Nuclear Information System (INIS)

Rack, T.; Stiller, M.; Nelson, K.; Zabler, S.; Rack, A.; Riesemeier, H.; Cecilia, A.

2011-01-01

Biocompatible materials such as titanium are regularly applied in oral surgery. Titanium-based implants for the replacement of missing teeth demand a high mechanical precision in order to minimize micro-bacterial leakage, especially when two-piece concepts are used. Synchrotron-based hard x-ray radiography, unlike conventional laboratory radiography, allows high spatial resolution in combination with high contrast even when micro-sized features in such highly attenuating objects are visualized. Therefore, micro-gap formation at interfaces in two-piece dental implants with the sample under different mechanical loads can be studied. We show the existence of micro-gaps in implants with conical connections and study the mechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential source of implant failure, i.e., bacterial leakage, which can be a stimulus for an inflammatory process.

A new three-dimensional, print-on-demand temporomandibular prosthetic total joint replacement system: Preliminary outcomes.

Science.gov (United States)

Dimitroulis, George; Austin, Stephen; Sin Lee, Peter Vee; Ackland, David

2018-05-16

The aim of this study is to present the preliminary clinical data on the OMX Temporomandibular Joint (TMJ) Prosthetic total joint replacement system. A prospective, cohort, clinical study was undertaken of consecutive adult patients with Category 5 end-stage joint disease who were implanted with the OMX TMJ prosthesis between May 2015 and April 2017. A total of 50 devices were implanted in 38 patients, with 12 patients receiving bilateral prosthetic joints. There were 31 females and 7 males in this cohort, who ranged in age from 20 to 66 years, with a mean of 43.8 years (±14.0 years). Ten of the 50 prosthetic joints (20%) were fully customized, while the remaining were patient matched using virtual planning software. Based on a mean follow-up period of 15.3 months (range 12-24 months) following the TMJ total joint replacement, preliminary results suggest the OMX TMJ prosthesis has made a positive impact on clinical outcomes, with a mean 74.4% reduction in joint pain levels and significant improvements (p < 0.05) in jaw function as measured by the visual analogue scales for mouth opening (30.8%), diet (77.1%), and function (59.2%). No device failures were reported during the study period. This study suggests that the print-on-demand OMX TMJ prosthesis, designed for rapid delivery of both patient-matched and fully customize devices, represents a safe, reliable and versatile implantable joint replacement system for the treatment of category 5 end-stage TMJ disease. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

DEFF Research Database (Denmark)

Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj

2013-01-01

Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

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.

Implant-retained dentures for full-arch rehabilitation: a case report comparing fixed and removable restorations.

Science.gov (United States)

Zafiropoulos, Gregory-George; Hoffman, Oliver

2011-01-01

Dental implants as abutments for full-arch restorations are a well-documented treatment modality. This report presents a case in which the patient was treated initially with fixed restorations supported by either implants or natural teeth and subsequently treated with a removable implant/telescopic crown-supported overdenture. Advantages and disadvantages of each approach are described and discussed. While the fixed restoration resulted in a functionally satisfactory treatment outcome, the patient was displeased with the esthetic appearance. The main concern was the unnaturally long tooth shape necessary to compensate for the insufficient alveolar ridge height. Replacement of the existing restoration with an implant-supported removable overdenture led to a functionally and esthetically acceptable result. When deciding whether to use a fixed or removable implant-supported full-arch restoration, a multitude of factors must be considered. Due to the possible need for additional surgical steps to enhance the esthetic appearance surrounding fixed restorations, removable implant-supported partial dentures often are the better choice.

Attachment systems for mandibular implant overdentures: a systematic review

Science.gov (United States)

Kim, Ha-Young; Lee, Jeong-Yol; Bryant, S. Ross

2012-01-01

PURPOSE The aim of this systematic review was to address treatment outcome according to attachment systems for mandibular implant overdentures in terms of implant survival rate, prosthetic maintenance and complications, and patient satisfaction. MATERIALS AND METHODS A systematic literature search was conducted using PubMed and hand searching of relevant journals considering inclusion and exclusion criteria. Clinical trial studies on mandibular implant overdentures until August, 2010 were selected if more than one type of overdenture attachment was reported. Twenty four studies from 1098 studies were finally included and the data on implant survival rate, prosthetic maintenance and complications, patient satisfaction were analyzed relative to attachment systems. RESULTS Four studies presented implant survival rates (95.8 - 97.5% for bar, 96.2 - 100% for ball, 91.7% for magnet) according to attachment system. Ten other studies presented an implant survival rate ranging from 93.3% to 100% without respect to the attachment groups. Common prosthetic maintenance and complications were replacement of an assay for magnet attachments, and activation of a matrix or clip for ball or bar attachments. Prosthetic maintenance and complications most commonly occurred in the magnet groups. Conflicting findings were found on the rate of prosthetic maintenance and complications comparing ball and bar attachments. Most studies showed no significant differences in patient satisfaction depending upon attachment systems. CONCLUSION The implant survival rate of mandibular overdentures seemed to be high regardless attachment systems. The prosthetic maintenance and complications may be influenced by attachment systems. However patient satisfaction may be independent of the attachment system. PMID:23236571

Biocompatibility of Advanced Manufactured Titanium Implants-A Review.

Science.gov (United States)

Sidambe, Alfred T

2014-12-19

Titanium (Ti) and its alloys may be processed via advanced powder manufacturing routes such as additive layer manufacturing (or 3D printing) or metal injection moulding. This field is receiving increased attention from various manufacturing sectors including the medical devices sector. It is possible that advanced manufacturing techniques could replace the machining or casting of metal alloys in the manufacture of devices because of associated advantages that include design flexibility, reduced processing costs, reduced waste, and the opportunity to more easily manufacture complex or custom-shaped implants. The emerging advanced manufacturing approaches of metal injection moulding and additive layer manufacturing are receiving particular attention from the implant fabrication industry because they could overcome some of the difficulties associated with traditional implant fabrication techniques such as titanium casting. Using advanced manufacturing, it is also possible to produce more complex porous structures with improved mechanical performance, potentially matching the modulus of elasticity of local bone. While the economic and engineering potential of advanced manufacturing for the manufacture of musculo-skeletal implants is therefore clear, the impact on the biocompatibility of the materials has been less investigated. In this review, the capabilities of advanced powder manufacturing routes in producing components that are suitable for biomedical implant applications are assessed with emphasis placed on surface finishes and porous structures. Given that biocompatibility and host bone response are critical determinants of clinical performance, published studies of in vitro and in vivo research have been considered carefully. The review concludes with a future outlook on advanced Ti production for biomedical implants using powder metallurgy.

Los implantes MG-OSSEOUS: Estudio multicéntrico retrospectivo MG-OSSEOUS implants: A multicentric retrospective study

Directory of Open Access Journals (Sweden)

E. Serrano Caturla

2006-12-01

commercial implants. Material and methodology. This is a retrospective multicentric study coordinated by a company called Scientific Management in O&SS (Barcelona, Spain. 1001 dental implants were placed in 247 patients and 328 prostheses were designed between 2004 and 2005, with a follow-up of two years. All implants were loaded with prostheses. We detail and analyze each implant, according to the diameter, length, position, surgical timing, loadings, design and types of prostheses and complementary surgical procedures, either synchronic or metachronic. Results. After the statistical method was homogenized, we were able to report an overall implant survival rate of 97.8% with monitoring of two years. The failures depending on the peculiarities of each clinical case are provided. No prosthetic failures are reported. Discussion. The criteria and indications applied by the professionals to the MG-OSSEOUS implants are standardized depending on the clinical case. Our results are compared with the international scientific literature, past and present, with these procedures totally agreeing with those found in the history of implantology. Finally, our survey is compared with those published by the Branemark team. Conclusion. The mixture between the quality of the MGOSSEOUS implants and the scientifically supported criteria regarding the implants, reveals an implant failure of 2.2% over two years, with a survival of 100% of both the replaced implants and the loaded prostheses.

Stress shielding and fatigue limits of poly-ether-ether-ketone dental implants.

Science.gov (United States)

Lee, Woo-Taek; Koak, Jai-Young; Lim, Young-Jun; Kim, Seong-Kyun; Kwon, Ho-Beom; Kim, Myung-Joo

2012-05-01

The poly-ether-ether-ketone (PEEK) polymer is of great interest as an alternative to titanium in orthopedics because of its biocompatibility and low elastic modulus. This study evaluated the fatigue limits of PEEK and the effects of the low elastic modulus PEEK in relation to existing dental implants. Compressive loading tests were performed with glass fiber-reinforced PEEK (GFR-PEEK), carbon fiber-reinforced PEEK (CFR-PEEK), and titanium rods. Among these tests, GFR-PEEK fatigue tests were performed according to ISO 14801. For the finite element analysis, three-dimensional models of dental implants and bone were constructed. The implants in the test groups were coated with a 0.5-mm thick and 5-mm long PEEK layer on the upper intrabony area. The strain energy densities (SED) were calculated, and the bone resorption was predicted. The fatigue limits of GFR-PEEK were 310 N and were higher than the static compressive strength of GFR-PEEK. The bone around PEEK-coated implants showed higher levels of SED than the bone in direct contact with the implants, and the wider diameter and stiffer implants showed lower levels of SED. The compressive strength of the GFR-PEEK and CFR-PEEK implants ranged within the bite force of the anterior and posterior dentitions, respectively, and the PEEK implants showed adequate fatigue limits for replacing the anterior teeth. Dental implants with PEEK coatings and PEEK implants may reduce stress shielding effects. Dental implant application of PEEK polymer-fatigue limit and stress shielding. Copyright © 2012 Wiley Periodicals, Inc.

The breast implant controversy.

Science.gov (United States)

Cook, R R; Harrison, M C; LeVier, R R

1994-02-01

The breast implant issue is a "bad news/good news" story. For many women with implants, the controversy has caused a fair degree of anxiety which may or may not be resolved as further information becomes available. It has also taken its toll on Dow Corning. Whole lines of medical products have been eliminated or are being phase out. The development of new medical applications has been terminated. As a consequence, employees have lost their jobs. What the effect will be on the biomedical industry as a whole remains to be seen (11). While silicones have been an important component in various medical devices, it is likely that other materials can be used as replacements. However, suppliers of non-silicone materials are also reevaluating their role in this market. For example, Du Pont, the nation's largest chemical company, has determined that the unpredictable and excessive costs of doing business with manufacturers of implantable medical devices no longer justifies the unrestricted sale of standard raw materials into this industry. Other companies are quietly following suit. On the up side, it is possible that the research being driven by this controversy will result in a greater understanding of the immunologic implications of xenobiotics, of the importance of nonbiased observations, of the need for ready access to valid data sets, and of the opportunity for valid scientific information to guide legal decisions. Only time will tell.

Evaluation of the Survival Rate and Bone Loss of Implants with Various Lengths

Directory of Open Access Journals (Sweden)

AR. Rokn

2006-12-01

Full Text Available Statement of Problem: The replacement of missing teeth with implant-associated restorations has become a widely used treatment modality in recent years. The length of dental implants may be a critical factor in achieving and maintaining osseointegration.Purpose: The aim of this study was to evaluate the survival rate and bone loss of dental implants with different lengthsMaterials and Methods: A retrospective cohort study was performed on 60 ITI-system implants, evenly distributed into three groups including 8, 10 and 12 mm high implants in the posterior segments of both jaws. Demographic information, oral hygiene,cigarette smoking, implant length, duration of implant placement (at least 24 months,bleeding on probing index and pocket probing depth were recorded for all participants.Bone loss was calculated using pre- and post-operative panoramic radiographs.Results: The mean rate of bone loss was different among the three groups and were found to be 0.21 (0.45, 0.3 (0.41 and 0.43 (0.55 mm in the 8, 10, and 12 mm high implants, respectively. Neither mean bone loss nor bleeding on probing index showed significant differences with implant length. A significant correlation was found between implant length and pocket probing depth (P<0.0001.Conclusion: The results of this study suggest that both short (8 mm high and long (10 or 12 mm high implants may be used with nearly equal success rates in the posterior segments of the jaws.

Interventions for replacing missing teeth: Antibiotics in dental implant placement to prevent complications: Evidence summary of Cochrane review

OpenAIRE

Jayaraman, Srinivasan

2015-01-01

The failure of dental implant can occurs at the preoperative planning stage, at the surgical stage, and at the postoperative stage. The success of this treatment can be increased if the clinical implant practice guidelines are prepared based on the recommendations from the highest level of research evidence (i.e.,) from systematic review of randomized controlled trials (RCTs) with meta-analysis. The Cochrane reviews of interventions are basically systematic reviews of RCTs with meta-analysis ...

In Vitro Evaluation of Leakage at Implant-Abutment Connection of Three Implant Systems Having the Same Prosthetic Interface Using Rhodamine B

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Antoine Berberi

2014-01-01

Full Text Available Objectives. Hollow space between implant and abutment may act as reservoir for commensal and/or pathogenic bacteria representing a potential source of tissue inflammation. Microbial colonization of the interfacial gap may ultimately lead to infection and bone resorption. Using Rhodamine B, a sensitive fluorescent tracer dye, we aim in this study to investigate leakage at implant-abutment connection of three implant systems having the same prosthetic interface. Materials and Methods. Twenty-one implants (seven Astra Tech, seven Euroteknika, and seven Dentium with the same prosthetic interface were connected to their original abutments, according to the manufacturers’ recommendation. After determination of the inner volume of each implant systems, the kinetic quantification of leakage was evaluated for each group using Rhodamine B (10−2 M. For each group, spectrophotometric analysis was performed to detect leakage with a fluorescence spectrophotometer at 1 h (T0 and 48 h (T1 of incubation time at room temperature. Results. Astra Tech had the highest inner volume (6.8 μL, compared to Dentium (4 μL and Euroteknika (2.9 μL. At T0 and T1, respectively, the leakage volume and percentage of each system were as follows: Astra Tech 0.043 μL or 1.48% (SD 0.0022, 0.08 μL or 5.56% (SD 0.0074, Euroteknika 0.09 μL or 6.93% (SD 0.0913, 0.21 μL or 20.55% (SD 0.0035, and Dentium 0.07 μL or 4.6% (SD 0.0029, 0.12 μL or 10.47% (SD 0.0072. Conclusion. The tested internal conical implant-abutment connections appear to be unable to prevent leakage. In average, Astra Tech implants showed the highest inner volume and the least leakage.

Early clinical outcome of aortic transcatheter valve-in-valve implantation in the Nordic countries

DEFF Research Database (Denmark)

Ihlberg, Leo; Nissen, Henrik Hoffmann; Nielsen, Niels Erik

2013-01-01

Transcatheter valve-in-valve implantation has emerged as an option, in addition to reoperative surgical aortic valve replacement, to treat failed biologic heart valve substitutes. However, the clinical experience with this approach is still limited. We report the comprehensive experience...

The effect of implant-supported removable partial dentures on oral health quality of life.

Science.gov (United States)

Gates, W Day; Cooper, Lyndon F; Sanders, Anne E; Reside, Glenn J; De Kok, Ingeborg J

2014-02-01

Removable partial dentures (RPDs) represent standard treatment for partial edentulism despite major shortcomings. To alleviate these shortcomings, endosseous implants provide support and stability as well as contribute to maintenance of alveolar bone. This prospective, within subject, time series study evaluated patient-based outcomes of RPDs compared to implant-supported removable partial dentures (ISRPDs). The study hypothesis was that the ISRPD would substantially improve oral health quality of life for patients. Seventeen patients requesting new mandibular Kennedy I or II RPDs received one 6-mm dental implant in one or both of the posterior edentulous areas. After healing, conventional RPDs were fabricated and delivered. Twelve weeks later, second-stage surgery was performed, and ball abutments with Clix attachments were inserted, thereby converting the prostheses to ISRPDs. Oral health quality of life was evaluated using the 49-item Oral Health Impact Profile (OHIP-49) questionnaire. The OHIP-49 was administered prior to treatment (baseline), at 6 and 12 weeks following RPD delivery and at 6 and 12 weeks following ISRPD conversion. Radiographic evaluation was performed at 6 and 12 weeks following ISRPD conversion. In statistical analysis, a fixed-slope random intercept variance components model took account of the multiple observations per person over time. In 17 subjects, 29 of 30 implants survived. The failed implant was replaced without complications. Abutment complications were limited to one abutment loosening and one attachment replacement. Minor prosthodontic complications were recorded. The OHIP-49 score reduced by 11.8 points, on average, at 12 weeks following ISRPD conversion (P = 0.011). Patients reported improved oral health following conversion to an ISRPD from RPD. The ISRPD involving short implants is one treatment option that should be considered when treatment planning Kennedy Class I and II patients. © 2012 John Wiley & Sons A/S.

A contact mechanics model for ankle implants with inclusion of surface roughness effects

International Nuclear Information System (INIS)

Hodaei, M; Farhang, K; Maani, N

2014-01-01

Total ankle replacement is recognized as one of the best procedures to treat painful arthritic ankles. Even though this method can relieve patients from pain and reproduce the physiological functions of the ankle, an improper design can cause an excessive amount of metal debris due to wear, causing toxicity in implant recipient. This paper develops a contact model to treat the interaction of tibia and talus implants in an ankle joint. The contact model describes the interaction of implant rough surfaces including both elastic and plastic deformations. In the model, the tibia and the talus surfaces are viewed as macroscopically conforming cylinders or conforming multi-cylinders containing micrometre-scale roughness. The derived equations relate contact force on the implant and the minimum mean surface separation of the rough surfaces. The force is expressed as a statistical integral function of asperity heights over the possible region of interaction of the roughness of the tibia and the talus implant surfaces. A closed-form approximate equation relating contact force and minimum separation is used to obtain energy loss per cycle in a load–unload sequence applied to the implant. In this way implant surface statistics are related to energy loss in the implant that is responsible for internal void formation and subsequent wear and its harmful toxicity to the implant recipient. (paper)

A contact mechanics model for ankle implants with inclusion of surface roughness effects

Science.gov (United States)

Hodaei, M.; Farhang, K.; Maani, N.

2014-02-01

Total ankle replacement is recognized as one of the best procedures to treat painful arthritic ankles. Even though this method can relieve patients from pain and reproduce the physiological functions of the ankle, an improper design can cause an excessive amount of metal debris due to wear, causing toxicity in implant recipient. This paper develops a contact model to treat the interaction of tibia and talus implants in an ankle joint. The contact model describes the interaction of implant rough surfaces including both elastic and plastic deformations. In the model, the tibia and the talus surfaces are viewed as macroscopically conforming cylinders or conforming multi-cylinders containing micrometre-scale roughness. The derived equations relate contact force on the implant and the minimum mean surface separation of the rough surfaces. The force is expressed as a statistical integral function of asperity heights over the possible region of interaction of the roughness of the tibia and the talus implant surfaces. A closed-form approximate equation relating contact force and minimum separation is used to obtain energy loss per cycle in a load-unload sequence applied to the implant. In this way implant surface statistics are related to energy loss in the implant that is responsible for internal void formation and subsequent wear and its harmful toxicity to the implant recipient.

PEEK Biomaterials in Trauma, Orthopedic, and Spinal Implants

Science.gov (United States)

Kurtz, S. M.; Devine, J. N.

2007-01-01

Since the 1980s, polyaryletherketones (PAEKs) have been increasingly employed as biomaterials for trauma, orthopedic, and spinal implants. We have synthesized the extensive polymer science literature as it relates to structure, mechanical properties, and chemical resistance of PAEK biomaterials. With this foundation, one can more readily appreciate why this family of polymers will be inherently strong, inert, and biocompatible. Due to its relative inertness, PEEK biomaterials are an attractive platform upon which to develop novel bioactive materials, and some steps have already been taken in that direction, with the blending of HA and TCP into sintered PEEK. However, to date, blended HA-PEEK composites have involved a trade-off in mechanical properties in exchange for their increased bioactivity. PEEK has had the greatest clinical impact in the field of spine implant design, and PEEK is now broadly accepted as a radiolucent alternative to metallic biomaterials in the spine community. For mature fields, such as total joint replacements and fracture fixation implants, radiolucency is an attractive but not necessarily critical material feature. PMID:17686513

A wireless power transmission system for implantable devices in freely moving rodents.

Science.gov (United States)

Eom, Kyungsik; Jeong, Joonsoo; Lee, Tae Hyung; Kim, Jinhyung; Kim, Junghoon; Lee, Sung Eun; Kim, Sung June

2014-08-01

Reliable wireless power delivery for implantable devices in animals is highly desired for safe and effective experimental use. Batteries require frequent replacement; wired connections are inconvenient and unsafe, and short-distance inductive coupling requires the attachment of an exterior transmitter to the animal's body. In this article, we propose a solution by which animals with implantable devices can move freely without attachments. Power is transmitted using coils attached to the animal's cage and is received by a receiver coil implanted in the animal. For a three-dimensionally uniform delivery of power, we designed a columnar dual-transmitter coil configuration. A resonator-based inductive link was adopted for efficient long-range power delivery, and we used a novel biocompatible liquid crystal polymer substrate as the implantable receiver device. Using this wireless power delivery system, we obtain an average power transfer efficiency of 15.2% (minimum efficiency of 10% and a standard deviation of 2.6) within a cage of 15×20×15 cm3.

Persistent Hypotony Associated with Immunosuppressive Therapy in Glaucoma Drainage Implant Surgery

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Susana Duch

2016-09-01

Full Text Available Purpose: To describe the histopathology of non-valved implant capsules in three cases of persistent postoperative hypotony after the restrictive tube ligature was released in patients receiving immunosuppressive therapy. Observations: The macroscopic appearance of the capsules 3 and 4 months postoperatively was immature and loose. Microscopic examination disclosed extremely irregular thin tissue, with thicknesses ranging from 0.02 to 0.6 mm, depending on the capsular location studied. Withdrawal of immunosuppressive therapy did not facilitate rebuilding of new capsules. Replacement with a valved implant device was necessary in two cases; the third case recovered with tapering of prednisone. Conclusions and Importance: The use of chronic systemic immunosuppressive therapy might interfere with capsular formation around the plates of drainage devices inducing persistent hypotony. In these cases, the use of valved implants might be safer.

Multi-scale modeling of photopolymerization for medical hydrogel-implant design

Science.gov (United States)

Schmocker, Andreas; Khoushabi, Azadeh; Farahi, Salma; Pioletti, Dominique; Bourban, Pierre-Etienne; Manson, Jan A.; Moser, Christophe

2013-02-01

We report on the modeling of a photopolymerizable hydrogel and its application as a replacement of the interior of the intervertebral disc (so called Nucleus Pulposus). The hydrogel is initially injected in its liquid form and then photopolymerized via a small catheter. Therefore, also the light necessary for the photopolymerization is constrained to a small light guide to keep the surgical procedure as minimally invasive as possible. Hence, the hydrogel is photopolymerized inside. For applications with restricted physical access and illumination time, such as an Nucleus Pulposus replacement, photopolymerization of volumes with a large volume/illumination-area ratio becomes highly challenging. During polymerization, the material's absorption and scattering coefficients change and directly influence local polymerization rates. By understanding and controlling such polymerization patterns, local material properties can be engineered (e.g. elastic modulus, swelling ratio), to match the set of mechanical requirements for the implant. Thus, it is essential to better understand and model photopolymerization reactions. Experiments were conducted by polymerizing a hydrogel in a column-like volume using an optical fiber for light delivery. Quantitative scattering and absorption values as well as monomer conversion rates of the hydrogel sample were validated using a newly established Monte Carlo model for photopolymerization. The results were used to study and predict 3D polymerization patterns for different illumination configurations. In particular, we show an example of a lumbar intervertebral disc replacement where the jelly core of the intervertebral disc (Nucleus Pulposus) is replaced by an in situ photopolymerized hydrogel. The results provide insights for the development of novel endoscopic light-scattering polymerization probes paving the way for a new generation of implantable hydrogels.

First reported experience with intramuscular diaphragm pacing in replacing positive pressure mechanical ventilators in children.

Science.gov (United States)

Onders, Raymond P; Ponsky, Todd A; Elmo, MaryJo; Lidsky, Karen; Barksdale, Edward

2011-01-01

Diaphragm pacing (DP) has been shown to successfully replace mechanical ventilators for adult tetraplegic patients with chronic respiratory insufficiency. This is the first report of DP in ventilator-dependent children. This was a prospective interventional experience under institutional review board approval. Diaphragm pacing involves outpatient laparoscopic diaphragm motor point mapping to identify the site where stimulation causes maximum diaphragm contraction with implantation of 4 percutaneous intramuscular electrodes. Diaphragm conditioning ensues to wean the child from the ventilator. Six children were successfully implanted ranging from 5 to 17 years old with the smallest 15 kg in weight. Length of time on mechanical ventilation ranged from 11 days to 7.6 years with an average of 3.2 years. In all patients, DP provided tidal volumes above basal needs. Five of the patients underwent a home-based weaning program, whereas one patient who was implanted only 11 days post spinal cord injury never returned to the ventilator with DP use. Another patient was weaned from the ventilator full time but died of complications of his underlying brain stem tumor. The remaining patients weaned from the ventilator for over 14 hours a day and/or are actively conditioning their diaphragms. Diaphragm pacing successfully replaced mechanical ventilators, which improves quality of life. Copyright © 2011 Elsevier Inc. All rights reserved.

An Implanted, Stimulated Muscle Powered Piezoelectric Generator

Science.gov (United States)

Lewandowski, Beth; Gustafson, Kenneth; Kilgore, Kevin

2007-01-01

A totally implantable piezoelectric generator system able to harness power from electrically activated muscle could be used to augment the power systems of implanted medical devices, such as neural prostheses, by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The features of our generator design are no moving parts and the use of a portion of the generated power for system operation and regulation. A software model of the system has been developed and simulations have been performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces have been experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to approximately 700 W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 50 W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and further investigation is underway.

Current State and Future Perspectives of Energy Sources for Totally Implantable Cardiac Devices.

Science.gov (United States)

Bleszynski, Peter A; Luc, Jessica G Y; Schade, Peter; PhilLips, Steven J; Tchantchaleishvili, Vakhtang

There is a large population of patients with end-stage congestive heart failure who cannot be treated by means of conventional cardiac surgery, cardiac transplantation, or chronic catecholamine infusions. Implantable cardiac devices, many designated as destination therapy, have revolutionized patient care and outcomes, although infection and complications related to external power sources or routine battery exchange remain a substantial risk. Complications from repeat battery replacement, power failure, and infections ultimately endanger the original objectives of implantable biomedical device therapy - eliminating the intended patient autonomy, affecting patient quality of life and survival. We sought to review the limitations of current cardiac biomedical device energy sources and discuss the current state and trends of future potential energy sources in pursuit of a lifelong fully implantable biomedical device.

Integrated VCOs for Medical Implant Transceivers

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Ahmet Tekin

2008-01-01

Full Text Available The 402–405 MHz medical implant communication service (MICS band has recently been allocated by the US Federal Communication Commission (FCC with the potential to replace the low-frequency inductive coupling techniques in implantable devices. This band was particularly chosen to provide full-integration, low-power, faster data transfer, and longer communication range. This paper investigates the design of a voltage-controlled oscillator (VCO that will be an essential building block of such wireless implantable devices operating in the MICS service band. Three different integrated quadrature VCOs that meet the requirements of the MICS standard are designed in 0.18 μm TSMC CMOS process to propose an optimum choice. Their performances in terms of power consumption, die area, linearity, and phase noise are compared. The fabricated VCOs are a four-stage differential ring VCO, an LC tank VCO directly loaded with a poly-phase filter, and an 800 MHz LC tank VCO with a high-frequency master-slave divider. All three architectures target a VCO gain of Kvco = 15 MHz/V with 3 calibration control and 2 frequency-shift keying (FSK control signals and are designed for 1.5 V supply voltage in a 0.18-μm standard CMOS process.

Short Implants: New Horizon in Implant Dentistry.

Science.gov (United States)

Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

2016-09-01

The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

A Survey of the Knowledge of Dental Implants as a Choice in ...

African Journals Online (AJOL)

Background: Dental implantology is fast becoming a specialty in the field of dentistry. Within the last five decades, dentistry appears to have recorded its most significant advancement in the field of dental implantology. With dental implants, missing teeth can now be replaced with stable, comfortable and natural-looking and ...

Replacement of a hopeless maxillary central incisor: a technique for the fabrication of an immediate implant-supported interim restoration.

Science.gov (United States)

Graiff, Lorenzo; Vigolo, Paolo

2012-04-01

Placement of a dental implant and an interim restoration in the esthetic zone immediately following tooth extraction is now a common procedure. However, in such clinical situations, the fabrication of an appropriate interim restoration may be challenging. The aim of this article is to present a technique for modifying the extracted tooth so it can be used as an implant-supported interim restoration.

Influence of Palatal Coverage and Implant Distribution on Implant Strain in Maxillary Implant Overdentures.

Science.gov (United States)

Takahashi, Toshihito; Gonda, Tomoya; Mizuno, Yoko; Fujinami, Yozo; Maeda, Yoshinobu

2016-01-01

Maxillary implant overdentures are often used in clinical practice. However, there is no agreement or established guidelines regarding prosthetic design or optimal implant placement configuration. The purpose of this study was to examine the influence of palatal coverage and implant number and distribution in relation to impact strain under maxillary implant overdentures. A maxillary edentulous model with implants and experimental overdentures with and without palatal coverage was fabricated. Four strain gauges were attached to each implant, and they were positioned in the anterior, premolar, and molar areas. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the implant strains were compared using one-way analysis of variance (P = .05). The palatolabial strain was much higher on anterior implants than on other implants in both denture types. Although there was no significant difference between the strain under dentures with and without palatal coverage, palateless dentures tended to result in higher implant strain than dentures with palatal coverage. Dentures supported by only two implants registered higher strain than those supported by four or six implants. Implants under palateless dentures registered higher strain than those under dentures with palatal coverage. Anterior implants exhibited higher palatolabial strain than other implants regardless of palatal coverage and implant configuration; it is therefore recommended that maxillary implant overdentures should be supported by six implants with support extending to the distal end of the arch.

Treatment of Orally Handicapped Edentulous Older Adults Using Dental Implants.

Science.gov (United States)

Zahedi, Charles

2016-07-01

The oral handicap of complete edentulism is the terminal outcome of a multifactorial process involving biological factors and patient-related factors. Fully edentulous orally handicapped older adults have been neglected because removable acrylic dentures have been the classic therapy for complete edentulism but are only rehabilitative, not therapeutic. Not replacing missing teeth with stable dentures could prevent adequate food intake. Osseointegrated endosseous implants used as a therapeutic adjunct can reduce the problem of long-term bone resorption to less than 0.1 mm per year. Implant-borne prostheses substantially increase the overall health and quality of life of orally handicapped fully edentulous older adults. Copyright © 2016 Elsevier Inc. All rights reserved.

Bony integration of titanium implants with a novel bioactive calcium titanate (Ca4Ti3O10) surface treatment in a rabbit model.

Science.gov (United States)

Haenle, Maximilian; Lindner, Tobias; Ellenrieder, Martin; Willfahrt, Manfred; Schell, Hanna; Mittelmeier, Wolfram; Bader, Rainer

2012-10-01

Nowadays total joint replacement is an indispensable component of modern medicine. The surfaces characteristics of cementless prostheses may be altered to achieve an accelerated and enduring bony integration. Classic surface coatings bear the risk of loosening or flaking from the implant body. This risk is excluded by the chemical conversion of the naturally existing TiO(2) surface layer into calcium titanate. The aim of this experimental animal study was to investigate the bony integration of implants with a new calcium titanate surface (Ca(4)Ti(3)O(10)) compared with a conventional standard Ti6Al4V surface. Cylindrical implants, made of titanium alloy (Ti6Al4V) were implanted in both lateral femoral condyles of New Zealand white rabbits. In each animal, an implant with and without surface treatment was inserted in a blinded manner. Animals were sacrificed after 4, 12, and 36 weeks, respectively. The axial pull-off forces were determined for 25 animals using a universal testing machine (Zwick Z010, Ulm, Germany). Furthermore, a histological analysis of the bony integration of the implants was performed in 12 specimens. In general, the pull-off forces for untreated and treated implants increased with longer survival times of the rabbits. No significant difference could be shown after 4 weeks between treated and untreated implants. After 12 weeks, the treated implants revealed a statistical significant higher pull-off force. After 36 weeks, the pull-off forces for treated and untreated implants aligned again. Titanium implants treated with calcium titanate, may offer an interesting and promising implant surface modification for endoprosthetic implants. They might lead to an accelerated osseointegration of total hip and knee replacements. Copyright © 2012 Wiley Periodicals, Inc.

[TRENDS OF PERMANENT PACEMAKER IMPLANTATION IN A SINGLE CENTER OVER A 20-YEAR PERIOD].

Science.gov (United States)

Antonelli, Dante; Ilan, Limor Bushar; Freedberg, Nahum A; Feldman, Alexander; Turgeman, Yoav

2015-05-01

To review the changes in permanent pacemaker implantation indications, pacing modes and patients' demographics over a 20-year period. We retrospectively retrieved data on patients who underwent first implantation of the pacemaker between 1-1-1991 and 31-12-2010. One thousand and nine (1,009) patients underwent a first pacemaker implantation during that period; 535 were men (53%), their mean age was 74.6±19.5 years; the highest rate of implanted pacemaker was in patients ranging in age from 70-79 years, however there was an increasing number of patients aged over 80 years. The median survival time after initial pacemaker implantation was 8 years. Syncope was the most common symptom (62.5%) and atrioventricular block was the most common electrocardiographic indication (56.4%) leading to pacemaker implantation. There was increased utilization of dual chamber and rate responsive pacemakers over the years. There was no difference regarding mode selection between genders. Pacemaker implantation rates have increased over a 20-year period. Dual chamber replaced most of the single ventricular chamber pacemaker and rate responsive pacemakers became the norm. The data of a small volume center are similar to those reported in pacemaker surveys of high volume pacemaker implantation centers. They confirm adherence to the published guidelines for pacing.

The manufacture of generic replicas of implants for arthroplasty of the hip and knee: is it regulated and will it save money?

Science.gov (United States)

Atrey, A; Heylen, S; Gosling, O; Porteous, M J L; Haddad, F S

2016-07-01

Joint replacement of the hip and knee remain very satisfactory operations. They are, however, expensive. The actual manufacturing of the implant represents only 30% of the final cost, while sales and marketing represent 40%. Recently, the patents on many well established and successful implants have expired. Companies have started producing and distributing implants that purport to replicate existing implants with good long-term results. The aims of this paper are to assess the legality, the monitoring and cost saving implications of such generic implants. We also assess how this might affect the traditional orthopaedic implant companies. Cite this article: Bone Joint J 2016;98-B:892-900. ©2016 The British Editorial Society of Bone & Joint Surgery.

Utilization of 3D/Dental software for precise implant site selection: clinical reports.

Science.gov (United States)

Kraut, R A

1992-01-01

Preoperative planning is an essential aspect of endosteal implant placement. Three-dimensional imaging allows the surgeon and restorative dentist to accurately visualize potential implant receptor sites relative to adjacent vital structures. This information is correlated with the planned occlusion, and transferred to the patient by means of a surgical prosthetic guide, which is developed on the diagnostic cast. The steps involved in planning and placing implants in an atrophic mandible in the first case illustrates the value of three-dimensional scanning in treating patients with limited bone volume. The second case presented with a mandibular bilateral distal extension partial denture, which was ultimately replaced with two implant-supported fixed prostheses. The use of three-dimensional imaging showed the location of the inferior alveolar neurovascular bundle which allowed utilization of all of the bone above it without encroaching on the nerve. The third case illustrates an edentulous maxilla where visualization of the osseous contour allowed for implant placement at an optimal angulation to provide support for the planned prosthesis.

TOTAL KNEE REPLACEMENT IN PATIENTS WITH BELOW-KNEE AMPUTATION

Science.gov (United States)

Karam, Matthew D; Willey, Michael; Shurr, Donald G

2010-01-01

Total knee replacement (TKR) is reserved for patients with severe and disabling arthritis that is non-responsive to conservative measures. Based on existing data, total knee replacement is a safe and cost-effective treatment for alleviating pain and improving physical function in patients who do not respond to conservative therapy. Despite the large variation in health status of patients and types of prosthesis implanted, total knee replacement has proven to be a relatively low risk and successful operation. Each year in the United States surgeons perform approximately 300,000 TKR.1 Likewise, lower extremity amputation is commonly performed in the United States with an annual incidence of 110,000 per year.2 Nearly 70% of all lower extremity amputations are performed as the result of chronic vascular disease, followed by trauma (22%), congenital etiology and tumor (4% each).3 Approximately 50% of all lower extremity amputations are performed secondary to complications from Diabetes Mellitus. Norvell et al. demonstrated that patients who have previously undergone transtibial amputation and ambulate with a prosthesis are more likely to develop degenerative joint disease in the con-tralateral extremity than the ipsilateral extremity.4 Further, radiographic changes consistent with osteoporosis have been demonstrated in up to 88% of limbs that have undergone transtibial amputation.8 To our knowledge, there have been only three reported cases of total knee replacement in patients with ipsilateral transtibial amputation.5,7 The purpose of the present study is to review the existing data on total knee replacement in patients who have undergone transtibial amputation. Further we present a patient with a transtibial amputation who underwent contralateral total knee replacement. PMID:21045987

Functional outcome in subretinal electronic implants depends on foveal eccentricity.

Science.gov (United States)

Stingl, Katarina; Bartz-Schmidt, Karl-Ulrich; Gekeler, Florian; Kusnyerik, Akos; Sachs, Helmut; Zrenner, Eberhart

2013-11-19

An active microelectronic subretinal implant, developed to replace the photoreceptive function in hereditary degenerations of the outer retina, has been applied in a pilot and clinical study in patients with end-stage retinal degeneration. The study population comprised 20 blind patients, all of whom lost vision as result of a hereditary retinal disease. An active visual implant was placed surgically within the subretinal space of each patient: subfoveal placement in eight patients (group 1) and parafoveal placement in 12 (group 2). Standardized low-vision tests, including light perception, light localization, movement detection, grating acuity, and visual acuity by Landolt C-rings, were used under masked, randomized implant-OFF and implant-ON conditions. For the chip-mediated vision functional results of both subject groups were compared. Three of 20 patients were excluded from analysis because of surgical or technical implant issues. Among patients with nonfoveal placement of the implant, 80% could perceive light, 10% recognized location, and 10% correctly distinguished stripe patterns up to a resolution of 0.33 cycles/degree. No nonfoveal placement patient passed the motion or Landolt C-ring tests. When the implant was placed subfoveally, 100% of patients could perceive light and determine light localization, 75% could resolve motion up to 35°/s, 88% correctly distinguished stripe patterns up to a resolution of 3.3 cycles/degree, and 38% passed a Landolt C-ring test with a decimal visual acuity of up to 20/546 (logMAR 1.43). Subfoveal placement of active subretinal visual implants allows superior measurable outcomes compared to para- or nonfoveal placement locations. (ClinicalTrials.gov numbers, NCT01024803, NCT00515814.).

Incidence and factors associated with infective endocarditis in patients undergoing left-sided heart valve replacement

DEFF Research Database (Denmark)

Østergaard, Lauge; Valeur, Nana; Ihlemann, Nikolaj

2018-01-01

Aims: Patients with left-sided heart valve replacement are considered at high-risk of infective endocarditis (IE). However, data on the incidence and risk factors associated with IE are sparse. Methods and results: Through Danish administrative registries, we identified patients who underwent left.......35-2.15), and cardiac implantable electronic device (CIED) (HR = 1.57, 95% CI 1.19-2.06) were among factors associated with an increased risk of IE. Conclusion: Infective endocarditis after left-sided heart valve replacement is not uncommon and occurs in about 1/20 over 10 years. Male, bioprosthetic valve, and heart...

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

Science.gov (United States)

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

2014-09-01

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

"Real life" longevity of implantable cardioverter-defibrillator devices.

Science.gov (United States)

Manolis, Antonis S; Maounis, Themistoklis; Koulouris, Spyridon; Vassilikos, Vassilios

2017-09-01

Manufacturers of implantable cardioverter-defibrillators (ICDs) promise a 5- to 9-year projected longevity; however, real-life data indicate otherwise. The aim of the present study was to assess ICD longevity among 685 consecutive patients over the last 20 years. Real-life longevity of ICDs may differ from that stated by the manufacturers. The study included 601 men and 84 women (mean age, 63.1 ± 13.3 years). The underlying disease was coronary (n = 396) or valvular (n = 15) disease, cardiomyopathy (n = 220), or electrical disease (n = 54). The mean ejection fraction was 35%. Devices were implanted for secondary (n = 562) or primary (n = 123) prevention. Single- (n = 292) or dual-chamber (n = 269) or cardiac resynchronization therapy (CRT) devices (n = 124) were implanted in the abdomen (n = 17) or chest (n = 668). Over 20 years, ICD pulse generator replacements were performed in 238 patients (209 men; age 63.7 ± 13.9 years; ejection fraction, 37.7% ± 14.0%) who had an ICD for secondary (n = 210) or primary (n = 28) prevention. The mean ICD longevity was 58.3 ± 18.7 months. In 20 (8.4%) patients, devices exhibited premature battery depletion within 36 months. Most (94%) patients had none, minor, or modest use of ICD therapy. Longevity was longest for single-chamber devices and shortest for CRT devices. Latest-generation devices replaced over the second decade lasted longer compared with devices replaced during the first decade. When analyzed by manufacturer, Medtronic devices appeared to have longer longevity by 13 to 18 months. ICDs continue to have limited longevity of 4.9 ± 1.6 years, and 8% demonstrate premature battery depletion by 3 years. CRT devices have the shortest longevity (mean, 3.8 years) by 13 to 17 months, compared with other ICD devices. These findings have important implications, particularly in view of the high expense involved with this type of electrical

Sources of patients’ knowledge on the treatment of missing teeth with implants

Directory of Open Access Journals (Sweden)

Szymanska Jolanta

2014-06-01

Full Text Available The number of patients who take the decision to have implantoprosthetic treatment keeps increasing. The aim of this study was to determine the sources of knowledge about possibilities of treating missing teeth with implants. The survey was conducted among 464 patients of both sexes aged from 20 to 74 years, treated with dental implants at the Non-Public Healthcare Centre “Dental” in Tomaszów Mazowiecki. The patients answered questions in an anonymous questionnaire. The questions included age, place of residence and source of knowledge about implants. Persons aged up to 40 years frequently obtained knowledge about the possibility of using implants from the media; patients aged 40-60 years - from their dentist, and people over 60 years of age - from family or friends. Persons living in rural areas or small town frequently acquired knowledge of the possibility of dental implants from the dentist, the city residents - from family or friends. The results of the survey indicate that the dentist is most commonly the main source of information about the possibility of replacing the missing teeth with implants, less family and friends and the media. The source of acquiring knowledge in this field varies depending on the age and place of residence of the persons concerned.

Biomedical Impact in Implantable Devices-The Transcatheter Aortic Valve as an example

Science.gov (United States)

Anastasiou, Alexandros; Saatsakis, George

2015-09-01

Objective: To update of the scientific community about the biomedical engineering involvement in the implantable devices chain. Moreover the transcatheter Aortic Valve (TAV) replacement, in the field of cardiac surgery, will be analyzed as an example of contemporary implantable technology. Methods: A detailed literature review regarding biomedical engineers participating in the implantable medical product chain, starting from the design of the product till the final implantation technique. Results: The scientific role of biomedical engineers has clearly been established. Certain parts of the product chain are implemented almost exclusively by experienced biomedical engineers such as the transcatheter aortic valve device. The successful professional should have a multidisciplinary knowledge, including medicine, in order to pursue the challenges for such intuitive technology. This clearly indicates that biomedical engineers are among the most appropriate scientists to accomplish such tasks. Conclusions: The biomedical engineering involvement in medical implantable devices has been widely accepted by the scientific community, worldwide. Its important contribution, starting from the design and extended to the development, clinical trials, scientific support, education of other scientists (surgeons, cardiologists, technicians etc.), and even to sales, makes biomedical engineers a valuable player in the scientific arena. Notably, the sector of implantable devices is constantly raising, as emerging technologies continuously set up new targets.

TWO-STAGE REVISION HIP REPLACEMENT PATIENS WITH SEVERE ACETABULUM DEFECT (CASE REPORT

Directory of Open Access Journals (Sweden)

V. V. Pavlov

2017-01-01

Full Text Available Favorable short-term results of arthroplasty are observed in 80–90% of cases, however, over the longer follow up period the percentage of positive outcomes is gradually reduced. Need for revision of the prosthesis or it’s components increases in proportion to time elapsed from the surgery. In addition, such revision is accompanied with a need to substitute the bone defect of the acetabulum. As a solution the authors propose to replace pelvic defects in two stages. During the first stage the defect was filled with bone allograft with platelet-rich fibrin (allografting with the use of PRF technology. After the allograft remodeling during the second stage the revision surgery is performed by implanting standard prostheses. The authors present a clinical case of a female patient with aseptic loosening of acetabular component of prosthesis in the right hip joint, with failed hip function of stage 2, right limb shortening of 2 cm. Treatment results confirm the efficiency and rationality of the proposed bone grafting option. The authors conclude bone allograft in combination with the PRF technology proves to be an alternative to the implantation of massive metal implants in the acetabulum while it reduces the risk of implant-associated infection, of metallosis in surrounding tissues and expands further revision options.

Wide-Range Highly-Efficient Wireless Power Receivers for Implantable Biomedical Sensors

KAUST Repository

Ouda, Mahmoud

2016-11-01

Wireless power transfer (WPT) is the key enabler for a myriad of applications, from low-power RFIDs, and wireless sensors, to wirelessly charged electric vehicles, and even massive power transmission from space solar cells. One of the major challenges in designing implantable biomedical devices is the size and lifetime of the battery. Thus, replacing the battery with a miniaturized wireless power receiver (WPRx) facilitates designing sustainable biomedical implants in smaller volumes for sentient medical applications. In the first part of this dissertation, we propose a miniaturized, fully integrated, wirelessly powered implantable sensor with on-chip antenna, designed and implemented in a standard 0.18μm CMOS process. As a batteryless device, it can be implanted once inside the body with no need for further invasive surgeries to replace batteries. The proposed single-chip solution is designed for intraocular pressure monitoring (IOPM), and can serve as a sustainable platform for implantable devices or IoT nodes. A custom setup is developed to test the chip in a saline solution with electrical properties similar to those of the aqueous humor of the eye. The proposed chip, in this eye-like setup, is wirelessly charged to 1V from a 5W transmitter 3cm away from the chip. In the second part, we propose a self-biased, differential rectifier with enhanced efficiency over an extended range of input power. A prototype is designed for the medical implant communication service (MICS) band at 433MHz. It demonstrates an efficiency improvement of more than 40% in the rectifier power conversion efficiency (PCE) and a dynamic range extension of more than 50% relative to the conventional cross-coupled rectifier. A sensitivity of -15.2dBm input power for 1V output voltage and a peak PCE of 65% are achieved for a 50k load. In the third part, we propose a wide-range, differential RF-to-DC power converter using an adaptive, self-biasing technique. The proposed architecture doubles

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.

Energy harvesting by implantable abiotically catalyzed glucose fuel cells

Science.gov (United States)

Kerzenmacher, S.; Ducrée, J.; Zengerle, R.; von Stetten, F.

Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the μW-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices.

Subgingival Microbiome Colonization and Cytokine Production during Early Dental Implant Healing.

Science.gov (United States)

Payne, Jeffrey B; Johnson, Paul G; Kok, Car Reen; Gomes-Neto, João C; Ramer-Tait, Amanda E; Schmid, Marian J; Hutkins, Robert W

2017-01-01

Little is known about longitudinal development of the peri-implant subgingival microbiome and cytokine production as a new sulcus forms after dental implant placement. Therefore, the purpose of this observational study was to evaluate simultaneous longitudinal changes in the oral microbiome and cytokine production in the developing peri-implant sulcus compared to control natural teeth. Four and 12 weeks after implant placement and abutment connection, a dental implant and a natural tooth were sampled in 25 patients for subgingival plaque and gingival crevicular fluid (GCF [around teeth] and peri-implant crevicular fluid [PICF] around implants). DNA from plaque samples was extracted and sequenced using Illumina-based 16S rRNA sequencing. GCF and PICF samples were analyzed using a customized Milliplex human cytokine and chemokine magnetic bead panel. Beta diversity analysis revealed that natural teeth and implants had similar subgingival microbiomes, while teeth had greater alpha diversity than implants. At the genus level, however, few differences were noted between teeth and dental implants over 12 weeks. Specifically, Actinomyces and Selenomonas were significantly elevated around teeth versus dental implants at both 4 weeks and 12 weeks, while Corynebacterium and Campylobacter were significantly elevated only at 4 weeks around teeth. The only difference between PICF and GCF biomarkers was significantly elevated granulocyte-macrophage colony-stimulating factor levels around teeth versus dental implants at the 4-week visit. The subgingival microbiome and cytokine production were similar between teeth and implants during early healing, suggesting that these profiles are driven by the patient following dental implant placement and are not determined by anatomical niche. IMPORTANCE Dental implants are a common treatment option offered to patients for tooth replacement. However, little is known regarding initial colonization of the subgingival microbiome and

Reduction of artefacts caused by hip implants in CT-based attenuation-corrected PET images using 2-D interpolation of a virtual sinogram on an irregular grid

NARCIS (Netherlands)

Abdoli, Mehrsima; de Jong, Johan R.; Pruim, Jan; Dierckx, Rudi A. J. O.; Zaidi, Habib

2011-01-01

Purpose Metallic prosthetic replacements, such as hip or knee implants, are known to cause strong streaking artefacts in CT images. These artefacts likely induce over-or underestimation of the activity concentration near the metallic implants when applying CT-based attenuation correction of positron

Systemic distribution of wear debris after hip replacement. A cause for concern?

Science.gov (United States)

Langkamer, V G; Case, C P; Heap, P; Taylor, A; Collins, C; Pearse, M; Solomon, L

1992-11-01

The production of particulate wear debris is a recognised complication of joint arthroplasty, but interest has concentrated on local tissue reactions and a possible association with implant loosening. The fate of wear products in the body remains unknown, although some of the metals used in the construction of orthopaedic implants are known to have toxic and oncogenic properties. We report histological and electron-microscopic evidence from two cases which shows that metallic debris can be identified in the lymphoreticular tissues of the body distant from the hip some years after joint replacement. The increase in the use of total arthroplasty in younger patients, the development of new alloys and the use of porous coatings must raise concern for the long-term effects of the accumulation of wear debris in the body.

Pulmonary heart valve replacement using stabilized acellular xenogeneic scaffolds; effects of seeding with autologous stem cells

Directory of Open Access Journals (Sweden)

Harpa Marius Mihai

2015-12-01

Full Text Available Background: We hypothesized that an ideal heart valve replacement would be acellular valve root scaffolds seeded with autologous stem cells. To test this hypothesis, we prepared porcine acellular pulmonary valves, seeded them with autologous adipose derived stem cells (ADSCs and implanted them in sheep and compared them to acellular valves.

Generator replacement is associated with an increased rate of ICD lead alerts.

Science.gov (United States)

Lovelock, Joshua D; Cruz, Cesar; Hoskins, Michael H; Jones, Paul; El-Chami, Mikhael F; Lloyd, Michael S; Leon, Angel; DeLurgio, David B; Langberg, Jonathan J

2014-10-01

Lead malfunction is an important cause of morbidity and mortality in patients with an implantable cardioverter-defibrillator (ICD). We have shown that the failure of recalled high-voltage leads significantly increases after ICD generator replacement. However, generator replacement has not been recognized as a predictor of lead failure in general. The purpose of this study is to assess the effect of ICD generator exchange on the rate of ICD lead alerts. A time-dependent Cox proportional hazards model was used to analyze a database of remotely monitored ICDs. The model assessed the impact of generator exchange on the rate of lead alerts after ICD generator replacement. The analysis included 60,219 patients followed for 37 ± 19 months. The 5-year lead survival was 99.3% (95% confidence interval 99.2%-99.4%). Of 60,219 patients, 7458 patients (12.9%) underwent ICD generator exchange without lead replacement. After generator replacement, the rate of lead alerts was more than 5-fold higher than in controls with leads of the same age without generator replacement (hazard ratio 5.19; 95% confidence interval 3.45-7.84). A large number of lead alerted within 3 months of generator replacement. Lead alerts were more common in patients with single- vs dual-chamber ICDs and in younger patients. Sex was not associated with lead alerts. Routine generator replacement is associated with a 5-fold higher risk of lead alert compared to age-matched leads without generator replacement. This suggests the need for intense surveillance after generator replacement and the development of techniques to minimize the risk of lead damage during generator replacement. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Prevalence, predictors, and prognostic implications of residual impairment of functional capacity after transcatheter aortic valve implantation

NARCIS (Netherlands)

Abdelghani, Mohammad; Cavalcante, Rafael; Miyazaki, Yosuke; de Winter, Robbert J.; Sarmento-Leite, Rogério; Mangione, José A.; Abizaid, Alexandre; Lemos, Pedro A.; Serruys, Patrick W.; de Brito, Fabio S.

2017-01-01

Background Patients with degenerative aortic stenosis (AS) referred for transcatheter aortic valve implantation (TAVI) typically have advanced cardiac and vascular adverse remodeling and multiple comorbidities and, therefore, might not recover a normal functional capacity after valve replacement. We

Polypyrrole RVC biofuel cells for powering medical implants.

Science.gov (United States)

Roxby, Daniel N; Ting, S R Simon; Nguyen, Hung T

2017-07-01

Batteries for implanted medical devices such as pacemakers typically require surgical replacement every 5 to 10 years causing stress to the patient and their families. A Biofuel cell uses two electrodes with enzymes embedded to convert sugar into electricity. To evaluate the power producing capabilities of biofuel cells to replace battery technology, polypyrrole electrodes were fabricated by compression with Glucose oxidase and Laccase. Vitreous carbon was added to increase the conductivity, whilst glutaraldehyde acted as a crosslinking molecule. A maximum open circuit potential of 558.7 mV, short circuit current of 1.09 mA and maximum power of 0.127 mW was obtained from the fuel cells. This was able to turn on a medical thermometer through a TI BQ25504 energy harvesting circuit, hence showing the powering potential for biomedical devices.

Restoration: Implant with Devastated Platform through Metal Post

Directory of Open Access Journals (Sweden)

Luna Salinas Tatiana

2017-01-01

Full Text Available Case Presentation. Implant prostheses are a successful treatment for replacing missing teeth. However, this treatment modality can have biological and mechanical complications causing serious problems for the dentist, as demonstrated in this clinical case. The patient presented with a fractured screw and a severely damaged implant hex connection that corresponded to the second premolar, upper left, stating that she unsuccessfully tried to remove the prosthetic screw, which was most likely to have been loose. After clinical and radiographic review, it was decided to remove small fragments of the fractured prosthetic screw inside the implant head. Removal by conventional methods was unsuccessful but was eventually achieved through use of a bur. Then it was possible to make a cast post (gold-palladium and develop a fixed prosthesis (silver-palladium, which were attached with luting cement. A cast post (gold-palladium was made and a fixed prosthesis was developed (silver-palladium, which were attached with luting cement, the same ones that can present mechanical complications such as fractures between the third and fourth thread of the implant, loosening of the abutment, and/or the prosthetic screw in individual crowns, most frequently in partially edentulous patients, mainly in the premolar and molar regions of the maxilla. Conclusion. Therefore the present technique used in this case is very simple, noninvasive, and useful to readers.

Sagittal tibiotalar translation and clinical outcomes in mobile and fixed-bearing total ankle replacement.

Science.gov (United States)

Usuelli, Federico G; Manzi, Luigi; Brusaferri, Giovanni; Neher, Robert E; Guelfi, Matteo; Maccario, Camilla

2017-06-01

Sagittal implant malalignment after total ankle replacement (TAR) has been considered to be a possible cause for premature implant failure. In a prior study, the change over time of the tibiotalar ratio (T-T ratio), which is the ratio between the posterior longitudinal talar length and the full longitudinal talar length, was assessed in 66 TARs where an unconstrained, mobile-bearing implant was implanted. The analysis documented an increase in the T-T ratio between 2 and 6 months post-surgery (on average from 34.6% to 37.2%). We hypothesized that this change might have been related to the presence of a mobile-bearing insert. In order to test our hypothesis, we designed a study to compare the translation of the talus in TARs performed with an unconstrained, mobile-bearing implant (designated the "Mobile ankle") and those performed with a semi-constrained, fixed-bearing implant (designated the "Fixed ankle"). The study included 71 consecutive patients (71 ankles) who underwent TAR with the Mobile ankle and 24 consecutive patients (24 ankles) who received the Fixed ankle from May 2011 to December 2014. Patients were assessed clinically and radiologically preoperatively (T 0 ), at 6 months (T 2 ) and 12 months (T 3 ) post-surgery. There was also a radiological assessment at 2 months post-surgery (T 1 ). The comparison of the T-T ratio between the two implant groups and over time indicated an interaction between time and group, therefore the changes of the T-T ratio over time were affected by the implant type factor (Pbearing interface. Copyright © 2016 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Application of RI power sources to cardiac pacemakers and aftercare in its implantation

International Nuclear Information System (INIS)

Hori, Motokazu

1974-01-01

RI power sources have long life when they are implanted into human bodies together with cardiac pacemakers, as compared with e.g. mercury batteries. Therefore, the frequency of their replacement can be by far less. However, there are the problems of radiation protection, high cost, availability, etc. The following matters are described: The cardiac pacemaker and its power supply, implantation into human body, problems with patients and conventional power sources; the current state of RI power sources for cardiac pacemakers, including plutonium-238 RTG and 147 Pm and 3 H batteries; and problems with the RI power sources. (Mori, K.)

Application of computer graphics in the design of custom orthopedic implants.

Science.gov (United States)

Bechtold, J E

1986-10-01

Implementation of newly developed computer modelling techniques and computer graphics displays and software have greatly aided the orthopedic design engineer and physician in creating a custom implant with good anatomic conformity in a short turnaround time. Further advances in computerized design and manufacturing will continue to simplify the development of custom prostheses and enlarge their niche in the joint replacement market.

A reduce and replace strategy for suppressing vector-borne diseases: insights from a stochastic, spatial model.

Directory of Open Access Journals (Sweden)

Kenichi W Okamoto

Full Text Available Two basic strategies have been proposed for using transgenic Aedes aegypti mosquitoes to decrease dengue virus transmission: population reduction and population replacement. Here we model releases of a strain of Ae. aegypti carrying both a gene causing conditional adult female mortality and a gene blocking virus transmission into a wild population to assess whether such releases could reduce the number of competent vectors. We find this "reduce and replace" strategy can decrease the frequency of competent vectors below 50% two years after releases end. Therefore, this combined approach appears preferable to releasing a strain carrying only a female-killing gene, which is likely to merely result in temporary population suppression. However, the fixation of anti-pathogen genes in the population is unlikely. Genetic drift at small population sizes and the spatially heterogeneous nature of the population recovery after releases end prevent complete replacement of the competent vector population. Furthermore, releasing more individuals can be counter-productive in the face of immigration by wild-type mosquitoes, as greater population reduction amplifies the impact wild-type migrants have on the long-term frequency of the anti-pathogen gene. We expect the results presented here to give pause to expectations for driving an anti-pathogen construct to fixation by relying on releasing individuals carrying this two-gene construct. Nevertheless, in some dengue-endemic environments, a spatially heterogeneous decrease in competent vectors may still facilitate decreasing disease incidence.

Management of Implantable Cardioverter Defibrillator Recipients: Care Beyond Guidelines.

Science.gov (United States)

Philippon, François; Sterns, Laurence D; Nery, Pablo B; Parkash, Ratika; Birnie, David; Rinne, Claus; Mondesert, Blandine; Exner, Derek; Bennett, Matthew

2017-08-01

This companion article is intended to address common clinical scenarios in patients with implantable defibrillators that were not addressed in the 2016 Canadian Cardiovascular Society/Canadian Heart Rhythm Society implantable cardioverter defibrillator guidelines including recommendations for device programming to improve detection, to minimize shocks (appropriate and inappropriate), and to minimize ventricular pacing. Important issues at the time of replacement such as device prescription, technical aspects (vascular access, extraction), and management of components on advisories are also discussed. Finally, common clinical scenarios such as management of patients with terminal illnesses, recurrent ventricular tachycardia, electrical storms, catheter ablation for ventricular tachycardia, and system infection management are considered. The management of these patients requires a team approach and comprehensive knowledge surrounding these common clinical scenarios. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Tricuspid Valve Dysfunction Following Pacemaker or Cardioverter-Defibrillator Implantation.

Science.gov (United States)

Chang, James D; Manning, Warren J; Ebrille, Elisa; Zimetbaum, Peter J

2017-05-09

The potential for cardiac implantable electronic device leads to interfere with tricuspid valve (TV) function has gained increasing recognition as having hemodynamic and clinical consequences associated with incremental morbidity and death. The diagnosis and treatment of lead-related (as distinct from functional) tricuspid regurgitation pose unique challenges. Because of pitfalls in routine diagnostic imaging, a high level of clinical suspicion must be maintained to avoid overlooking the possibility that worsening heart failure is a consequence of mechanical interference with TV leaflet mobility or coaptation and is amenable to lead extraction or valve repair or replacement. The future of cardiac implantable electronic devices includes pacing and perhaps defibrillation without a lead traversing the TV. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Total Ossicular Replacement Prosthesis: A New Fat Interposition Technique

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Issam Saliba

2018-01-01

Full Text Available Objective: To compare audiometric results between the standard total ossicular replacement prosthesis (TORP-S and a new fat interposition total ossicular replacement prosthesis (TORP-F in pediatric and adult patients and to assess the complication and the undesirable outcome. Study design: This is a retrospective study. Methods: This study included 104 patients who had undergone titanium implants with TORP-F and 54 patients who had undergone the procedure with TORP-S between 2008 and 2013 in our tertiary care centers. The new technique consists of interposing a fat graft between the 4 legs of the universal titanium prosthesis (Medtronic Xomed Inc, Jacksonville, FL, USA to provide a more stable TORP in the ovale window niche. Normally, this prosthesis is designed to fit on the stapes’ head as a partial ossicular replacement prosthesis. Results: The postoperative air-bone gap less than 25 dB for the combined cohort was 69.2% and 41.7% for the TORP-F and the TORP-S groups, respectively. The mean follow-up was 17 months postoperatively. By stratifying data, the pediatric cohort shows 56.5% in the TORP-F group (n = 52 compared with 40% in the TORP-S group (n = 29. However, the adult cohort shows 79.3% in the TORP-F group (n = 52 compared with 43.75% in the TORP-S group (n = 25. These improvements in hearing were statistically significant. There were no statistically significant differences in the speech discrimination scores. The only undesirable outcome that was statistically different between the 2 groups was the prosthesis displacement: 7% in the TORP-F group compared with 19% in the TORP-S group ( P  = .03. Conclusions: The interposition of a fat graft between the legs of the titanium implants (TORP-F provides superior hearing results compared with a standard procedure (TORP-S in pediatric and adult populations because of its better stability in the oval window niche.

Total Ossicular Replacement Prosthesis: A New Fat Interposition Technique.

Science.gov (United States)

Saliba, Issam; Sabbah, Valérie; Poirier, Jackie Bibeau

2018-01-01

To compare audiometric results between the standard total ossicular replacement prosthesis (TORP-S) and a new fat interposition total ossicular replacement prosthesis (TORP-F) in pediatric and adult patients and to assess the complication and the undesirable outcome. This is a retrospective study. This study included 104 patients who had undergone titanium implants with TORP-F and 54 patients who had undergone the procedure with TORP-S between 2008 and 2013 in our tertiary care centers. The new technique consists of interposing a fat graft between the 4 legs of the universal titanium prosthesis (Medtronic Xomed Inc, Jacksonville, FL, USA) to provide a more stable TORP in the ovale window niche. Normally, this prosthesis is designed to fit on the stapes' head as a partial ossicular replacement prosthesis. The postoperative air-bone gap less than 25 dB for the combined cohort was 69.2% and 41.7% for the TORP-F and the TORP-S groups, respectively. The mean follow-up was 17 months postoperatively. By stratifying data, the pediatric cohort shows 56.5% in the TORP-F group (n = 52) compared with 40% in the TORP-S group (n = 29). However, the adult cohort shows 79.3% in the TORP-F group (n = 52) compared with 43.75% in the TORP-S group (n = 25). These improvements in hearing were statistically significant. There were no statistically significant differences in the speech discrimination scores. The only undesirable outcome that was statistically different between the 2 groups was the prosthesis displacement: 7% in the TORP-F group compared with 19% in the TORP-S group ( P  = .03). The interposition of a fat graft between the legs of the titanium implants (TORP-F) provides superior hearing results compared with a standard procedure (TORP-S) in pediatric and adult populations because of its better stability in the oval window niche.

An instrumented implant for in vivo measurement of contact forces and contact moments in the shoulder joint.

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Westerhoff, P; Graichen, F; Bender, A; Rohlmann, A; Bergmann, G

2009-03-01

To improve implant design, fixation and preclinical testing, implant manufacturers depend on realistic data of loads acting on the shoulder joint. Furthermore, these data can help to optimize physiotherapeutic treatment and to advise patients in their everyday living conditions. Calculated shoulder joint loads vary extremely among different authors [Anglin C, Wyss UP, Pichora DR. Glenohumeral contact forces. Proc Inst Mech Eng [H] 2000;214:637-44]. Additionally the moments acting in the joint caused by friction or incongruent articular surfaces, for example, are not implemented in most models. An instrumented shoulder joint implant was developed to measure the contact forces and the contact moments acting in the glenohumeral joint. This article provides a detailed description of the implant, containing a nine-channel telemetry unit, six load sensors and an inductive power supply, all hermetically sealed inside the implant. The instrumented implant is based on a clinically proven BIOMET Biomodular shoulder replacement and was calibrated before implantation by using complex mathematical calculation routines in order to achieve an average measuring precision of approximately 2%.

Implantes mamarios en el plano subfascial en reemplazo del bolsillo subglandular: un cambio lógico Breast implants in the subfascial plane in replacement of the subglandular pocket: a logical change

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O.D. Ventura

2006-03-01

Full Text Available Desde 1999 hemos cambiado el plano subglandular del bolsillo de los implantes mamarios por el plano subfascial (subaponeurótico. Este plano se halla por debajo de la fascia aponeurótica del músculo pectoral mayor, serrato, oblicuo lateral y recto anterior. Este artículo considera 150 casos implantados en este plano (subfascial. Se utilizaron prótesis de superficie texturada. El abordaje fue por una incisión periareolar inferior. En todos los pacientes se consiguió una excelente cobertura del implante, al igual que una forma y movilidad natural. En ningún caso se observó el desagradable ondulado de cuadrantes superiores, conocido como rippling. Cuatro de ellos presentaron procesos capsulares contráctiles grado II de Baker (2,6%. En el postoperatorio inmediato se registró menor edema y una recuperación más rápida de lo habitual, de acuerdo a nuestra experiencia con los otros procedimientos (submuscular y subglandular. Cuando la elección del bolsillo es subglandular, el plano subfascial parecería ser el lugar lógico de la colocación de los implantes mamarios.Since 1999, the subglandular plane of the pocket has been substituted in our practise for the subfascial (subaponeurotic plane in breast implants. This plane lies underneath the aponeurotic fascia of the pectoralis major , the serratus, the lateral oblique and the rectus anterior muscles. This article describes 150 patients with implants in the subaponeurotic plane and textured surface. Patients were approached through an inferior periareolar incision. Excellent coverage of the implant, as well as natural shape and mobility were achieved in all patients. No ondulation (rippling in the upper half of the breast has been observed. Four patients (2,6% had Baker grade II capsular contracture. In the immediate post-op, less edema and faster-than-usual recovery could be seen versus our experience with other (submuscular and subglandular procedures. When a subglandular pocket is the

Immediate and early function of Brånemark System implants placed in the esthetic zone: a 1-year prospective clinical multicenter study.

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Maló, Paulo; Friberg, Bertil; Polizzi, Giovanni; Gualini, Federico; Vighagen, Torbjörn; Rangert, Bo

2003-01-01

Immediate/early implant function means great benefits for patients and therapists because treatment time and cost can be substantially reduced. This concept has become an accepted alternative for complete arch fixed restorations in the mandible, and clinical documentation is emerging for other indications. The purpose of this prospective clinical multicenter study was to evaluate the outcome of implants placed in incisor, canine, and premolar regions in maxillas or mandibles. Implants were loaded with provisional crowns and bridges on the same day or within a few days and were followed up for 1 year during function. Four centers treated 76 patients each in need of an implant-retained prosthesis in the anterior and premolar regions in the maxilla or mandible. A total of 116 titanium implants with machined surfaces (Brånemark System , Nobel Biocare AB, Gothenburg, Sweden) were placed: 74 in maxillas and 42 in mandibles. Eighty-seven prostheses were made, of which 63 were single crowns and 24 were bridges (supported by 53 splinted implants). Twenty-two implants in 14 patients were placed in fresh extraction sites. The goal with the preparation and insertion technique was to achieve good primary implant stability and a minimum implant insertion torque of 30 Ncm before the implant was completely seated. The occlusion was adjusted to eliminate direct contact with the provisional prostheses. After 6 months, the patients received their permanent prostheses. Sixty-seven patients were followed for 1 year. Five implants were lost in five patients, three in the maxilla and two in the mandible. Four of the lost implants were single-tooth replacements and one was splinted. The cumulative survival rate (CSR) was 95.7% for all implants after 1 year and 93.7% and 98.1% for single-tooth and splinted implants, respectively. There were no implant losses in the extraction sites. The CSR of 96% at 1 year indicates that immediate function of Brånemark System implants placed in incisor

Implantation of D+ ions in niobium and deuterium gas reemission

International Nuclear Information System (INIS)

Pisarev, A.A.; Tel'kovskij, V.G.

1975-01-01

This is a study of the implanting and reflex gasoisolation of D ions in niobium. It has been discovered that deutrium scope and gasoisolation are defined by several processes. An assumption is made that in ion bombarding conditions the implanting solutions are possible to exist and that deutrium can be replaced on the basis of niobium and hydrid compounds NbxDy. The portion of the particles entrained in the metal in one or another way depends on the ion energy. The dependence of the scope coefficient of n D + ions from the target temperature in the range of 290-1500 K was registered. An increase of the scope coefficient of the ions at high temperature with an increase of the ion energy was discovered

Homojunction silicon solar cells doping by ion implantation

Science.gov (United States)

Milési, Frédéric; Coig, Marianne; Lerat, Jean-François; Desrues, Thibaut; Le Perchec, Jérôme; Lanterne, Adeline; Lachal, Laurent; Mazen, Frédéric

2017-10-01

Production costs and energy efficiency are the main priorities for the photovoltaic (PV) industry (COP21 conclusions). To lower costs and increase efficiency, we are proposing to reduce the number of processing steps involved in the manufacture of N-type Passivated Rear Totally Diffused (PERT) silicon solar cells. Replacing the conventional thermal diffusion doping steps by ion implantation followed by thermal annealing allows reducing the number of steps from 7 to 3 while maintaining similar efficiency. This alternative approach was investigated in the present work. Beamline and plasma immersion ion implantation (BLII and PIII) methods were used to insert n-(phosphorus) and p-type (boron) dopants into the Si substrate. With higher throughput and lower costs, PIII is a better candidate for the photovoltaic industry, compared to BL. However, the optimization of the plasma conditions is demanding and more complex than the beamline approach. Subsequent annealing was performed on selected samples to activate the dopants on both sides of the solar cell. Two annealing methods were investigated: soak and spike thermal annealing. Best performing solar cells, showing a PV efficiency of about 20%, was obtained using spike annealing with adapted ion implantation conditions.

Early Loading of Single-Piece Implant for Partially Edentulous Posterior Arch: A Prospective One-Year Case Report

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Amol Beldar

2013-01-01

Full Text Available Implant therapy is now well established, and there is an increasing need for shorter rehabilitation time. Original prerequisites of osseointegration have been reassessed to satisfy continuously increasing patient's expectation of reduced treatment time, improved esthetics, and increased comfort. Shorter healing time may be appropriate in some circumstances, and examples of early loading have been reported in animal and human studies. However, to date there are insufficient data to determine a universally acceptable opinion on early loading of implants for single-tooth replacement. This case report involves early loading, combined with construction of a restoration, inserted directly after 6 weeks of implant surgery and followup of one year.

Need of implant dentistry at undergraduate dental curriculum in Indian dental colleges

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Ramesh Chowdhary

2011-01-01

Full Text Available Edentulism is the major problem in the developing countries, and is widely spread in the current population, although the prevalence is declining and incidence of tooth loss is decreasing in the developed nations. The prevalence of edentulism in India varies from 60% to 69% of 25 years and above age group. It is obvious that the number of lost teeth increases with age leading to an increase in prevalence of partially edentulous patients. From a biological point of view, the replacement of a single missing tooth with an implant rather than a three-unit fixed partial denture, and the implant-supported complete denture has been proved more efficient in improving the mastication and maintaining the bone for a longer time and also more cost-effective treatment. Many dental schools throughout Europe and America have to a various extent introduced implant dentistry as part of the compulsory undergraduate curriculum. Thus, it becomes more essential to introduce implant dentistry at undergraduate level in Indian dental schools to manage the higher percentage of edentulism.

Ion implantation

International Nuclear Information System (INIS)

Dearnaley, Geoffrey

1975-01-01

First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

Analysis of the radiobiology of ytterbium-169 and iodine-125 permanent brachytherapy implants

Energy Technology Data Exchange (ETDEWEB)

Lazarescu, G.R. [Windsor Regional Cancer Center, Ontario Cancer Treatment and Research Foundation, Windsor, Canada N8W 2X3 (Canada); Battista, J.J. [London Regional Cancer Center, Ontario Cancer Treatment and Research Foundation, Dept. of Oncology and Dept. of Medical Biophysics, University of Western Ontario, London, Canada N6A 4L6 (Canada)

1997-09-01

Recently, Yb-169 has been considered as a potential replacement for I-125 and Pd-103 in permanent implants. In spite of the uncertainties in the parameters necessary for an accurate radiobiological modelling, the linear quadratic model can be useful in the comparative evaluation of the radiotherapeutic merit of similar implants. In order to find out if a Yb-169 permanent implant can be made biologically 'equivalent' to an I-125 implant, we studied the dependence of local control on the tumour cell radiosensitivity and on the balance between the rate of tumour cell killing and tumour cell proliferation, for rapidly and slowly proliferating tumours. The extrapolated response dose (ERD) has been calculated for tumour and late reacting normal tissue for both types of implants and the possible biological restrictions due to the normal tissue tolerance have been discussed. Our theoretical analysis is consistent with the clinical results published for I-125 permanent implants in prostate tumours and meningiomas. It predicts that Yb-169, which has only recently been used in human tumours, can provide comparable tumour control for permanent implants in slowly proliferating tumours with an initial dose rate of 13 cGy h{sup -1}. Control might be extended to rapidly proliferating tumours by increasing the initial dose rate within a range consistent with an acceptable level of normal tissue late reaction. (author)

Demineralized bone matrix and human cancellous bone enhance fixation of porous-coated titanium implants in sheep

DEFF Research Database (Denmark)

Babiker, Hassan; Ding, Ming; Overgaard, Søren

2016-01-01

matrix (DBM), alone or in combination with allograft or commercially available human cancellous bone (CB), may replace allografts, as they have the capability of inducing new bone and improving implant fixation through enhancing bone ongrowth. The purpose of this study was to investigate the effect...... of DBM alone, DBM with CB, or allograft on the fixation of porous-coated titanium implants. DBM100 and CB produced from human tissue were included. Both materials are commercially available. DBM granules are placed in pure DBM and do not contain any other carrier. Titanium alloy implants, 10 mm long × 10...... mm diameter, were inserted bilaterally into the femoral condyles of eight skeletally mature sheep. Thus, four implants with a concentric gap of 2 mm were implanted in each sheep. The gap was filled with: (a) DBM; (b) DBM:CB at a ratio of 1:3; (c) DBM:allograft at a ratio of 1:3; or (d) allograft...

Immunohistochemical evaluation: The effects of propolis on osseointegration of dental implants in rabbit′s tibia

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Bushra Habeeb Al-Molla

2014-01-01

Full Text Available Background: Dental implant is an artificial tooth root-fixed into the jaws to hold a replacement tooth or bridge. Functional surface modifications by organic material such as propolis coating seem to enhance early peri-implant bone formation, enhancing the initial cell attachment. The aim of the study was to study the expression of osteocalcin (OC and type I collagen (COLL1 as bone formation markers in propolis-coated and -uncoated implant in interval periods (1, 2, 4, and 6 weeks. Materials and Methods: Commercially pure titanium (cpTi implants, coated with propolis protein, were placed in the tibias of 40 New Zealand white rabbits, histological and immunohistochemical tests for detection of expression of OC and COLL1were performed on all the implants of both control and experimental groups for (1, 2, 4, and 6 weeks healing intervals. Results: Histological finding for coated titanium implant with propolis illustrated an early bone formation, mineralization, and maturation in comparison to control. Immunohistochemical finding showed that positive reaction for OC and COLL1 was expressed by osteoblast cells at implants coated with propolis, indicating that bone formation and maturation was accelerated by adding biological materials as a modification modality of implant surface. Conclusion: The present study concludes that coating of implants with propolis showed increment in osseointegration in short interval period.

Does antibiotic prophylaxis at implant placement decrease early implant failures? A Cochrane systematic review.

Science.gov (United States)

Esposito, Marco; Grusovin, Maria Gabriella; Loli, Vasiliki; Coulthard, Paul; Worthington, Helen V

2010-01-01

Marco Esposito is the first author of two of the included studies; however, he was not involved in the quality assessment of these trials. This review is based on a Cochrane systematic review entitled 'Interventions for replacing missing teeth: antibiotics at dental implant placement to prevent complications' published in The Cochrane Library (see http://www.cochrane.org for more information). Cochrane systematic reviews are regularly updated to include new research, and in response to comments and criticisms from readers. If you wish to comment on this review, please send your comments to the Cochrane website or to Marco Esposito. The Cochrane Library should be consulted for the most recent version of the review. The results of a Cochrane Review can be interpreted differently, depending on people's perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by the Cochrane Collaboration. To assess the beneficial or harmful effects of systemic prophylactic antibiotics at dental implant placement versus no antibiotic/placebo administration and, if antibiotics are of benefit, to find which type, dosage and duration is the most effective. The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched up to 2 June 2010 for randomised controlled clinical trials (RCTs) with a follow-up of at least 3 months comparing the administration of various prophylactic antibiotic regimens versus no antibiotics to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections and adverse events (gastrointestinal, hypersensitivity, etc.). Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. Meta-analyses were

Study and realisation of plane optical waveguides in amorphous silica by ion implantation

International Nuclear Information System (INIS)

Moutonnet, Danielle

1974-01-01

Within the framework of the replacement of radio-electric waves by light waves as support of information transmission in telecommunications, this research thesis addresses the use of ion implantation for the development of small waveguides with low losses. The author first describes how such waveguides can be characterised by studying the propagation of an electromagnetic wave in a plane waveguide, and the different ways to introduce energy in these waveguides. Then, she discusses how the obtained results can be used to determine the main parameters of an optical waveguide, or more generally of a thin transparent layer for a chosen wavelength. In the second part, the author reports the application of this general method to the case of guides obtained by ion implantation. She notably identifies the possibilities of ion implantation as technological tool to develop waveguides, and discusses how the performed experiments allow a better understanding of physical mechanisms occurring during implantation. In this second part, she recalls generally admitted theories about ion implantation, describes experiment principles (implantation of oxygen or nitrogen ions into amorphous silica followed by annealing) and discusses the obtained results (increase of the refraction index, i.e. of the guiding effect, stronger for oxygen than for nitrogen) [fr

Development of implant/interconnected porous hydroxyapatite complex as new concept graft material.

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Kazuya Doi

Full Text Available BACKGROUND: Dental implant has been successfully used to replace missing teeth. However, in some clinical situations, implant placement may be difficult because of a large bone defect. We designed novel complex biomaterial to simultaneously restore bone and place implant. This complex was incorporated implant into interconnected porous calcium hydroxyapatite (IP-CHA. We then tested this Implant/IP-CHA complex and evaluated its effect on subsequent bone regeneration and implant stability in vivo. METHODOLOGY/PRINCIPAL FINDINGS: A cylinder-type IP-CHA was used in this study. After forming inside of the cylinder, an implant was placed inside to fabricate the Implant/IP-CHA complex. This complex was then placed into the prepared bone socket in the femur of four beagle-Labrador hybrid dogs. As a control, implants were placed directly into the femur without any bone substrate. Bone sockets were allowed to heal for 2, 3 and 6 months and implant stability quotients (ISQ were measured. Finally, tissue blocks containing the Implant/IP-CHA complexes were harvested. Specimens were processed for histology and stained with toluidine blue and bone implant contact (BIC was measured. The ISQs of complex groups was 77.8±2.9 in the 6-month, 72.0±5.7 in the 3-month and 47.4±11.0 in the 2-month. There was no significant difference between the 3- or 6-month complex groups and implant control groups. In the 2-month group, connective tissue, including capillary angiogenesis, was predominant around the implants, although newly formed bone could also be observed. While, in the 3 and 6-month groups, newly formed bone could be seen in contact to most of the implant surface. The BICs of complex groups was 2.18±3.77 in the 2-month, 44.03±29.58 in the 3-month, and 51.23±8.25 in the 6-month. Significant difference was detected between the 2 and 6-month. CONCLUSIONS/SIGNIFICANCE: Within the results of this study, the IP-CHA/implant complex might be able to achieve both

Engineered Protein Coatings to Improve the Osseointegration of Dental and Orthopaedic Implants

Science.gov (United States)

Raphel, Jordan; Karlsson, Johan; Galli, Silvia; Wennerberg, Ann; Lindsay, Christopher; Haugh, Matthew; Pajarinen, Jukka; Goodman, Stuart B.; Jimbo, Ryo; Andersson, Martin; Heilshorn, Sarah C.

2016-01-01

Here we present the design of an engineered, elastin-like protein (ELP) that is chemically modified to enable stable coatings on the surfaces of titanium-based dental and orthopaedic implants by novel photocrosslinking and solution processing steps. The ELP includes an extended RGD sequence to confer bio-signaling and an elastin-like sequence for mechanical stability. ELP thin films were fabricated on cp-Ti and Ti6Al4V surfaces using scalable spin and dip coating processes with photoactive covalent crosslinking through a carbene insertion mechanism. The coatings withstood procedures mimicking dental screw and hip replacement stem implantations, a key metric for clinical translation. They promoted rapid adhesion of MG63 osteoblast-like cells, with over 80% adhesion after 24 hours, compared to 38% adhesion on uncoated Ti6Al4V. MG63 cells produced significantly more mineralization on ELP coatings compared to uncoated Ti6Al4V. Human bone marrow mesenchymal stem cells (hMSCs) had an earlier increase in alkaline phosphatase activity, indicating more rapid osteogenic differentiation and mineral deposition on adhesive ELP coatings. Rat tibia and femur in vivo studies demonstrated that cell-adhesive ELP-coated implants increased bone-implant contact area and interfacial strength after one week. These results suggest that ELP coatings withstand surgical implantation and promote rapid osseointegration, enabling earlier implant loading and potentially preventing micromotion that leads to aseptic loosening and premature implant failure. PMID:26790146

Impact of patient-prosthesis mismatch after transcatheter aortic valve-in-valve implantation in degenerated bioprostheses.

Science.gov (United States)

Seiffert, Moritz; Conradi, Lenard; Baldus, Stephan; Knap, Malgorzata; Schirmer, Johannes; Franzen, Olaf; Koschyk, Dietmar; Meinertz, Thomas; Reichenspurner, Hermann; Treede, Hendrik

2012-03-01

Transcatheter valve-in-valve implantation is evolving as an alternative to reoperative valve replacement in high-risk patients with degenerated bioprostheses. Nevertheless, hemodynamic performance is limited by the previously implanted xenograft. We report our experience with patient-prosthesis mismatch (PPM) after valve-in-valve implantation in the aortic position. Eleven patients (aged 79.3 ± 6.1 years) received transapical implantation of a balloon-expandable pericardial heart valve into a degenerated bioprosthesis (size, 23.9 ± 1.6 mm; range, 21-27 mm) in the aortic position. All patients were considered high risk for surgical valve replacement (logistic European System for Cardiac Operative Risk Evaluation, 31.8% ± 24.1%). Severe PPM was defined as an indexed effective orifice area less than 0.65 cm(2)/m(2), determined by discharge echocardiography. Severe PPM was evident in 5 patients (group 1) and absent in 6 patients (group 2). Mean transvalvular gradients decreased from 29.2 ± 15.4 mm Hg before implantation to 21.2 ± 9.7 mm Hg at discharge (group 1) and from 28.2 ± 9.0 mm Hg before implantation to 15.2 ± 6.5 mm Hg at discharge (group 2). Indexed effective orifice area increased from 0.5 ± 0.1 cm(2)/m(2) to 0.6 ± 0.1 cm(2)/m(2) and from 0.6 ± 0.3 cm(2)/m(2) to 0.8 ± 0.3 cm(2)/m(2). Aortic regurgitation decreased from grade 2.0 ± 1.1 to 0.4 ± 0.5 overall. No differences in New York Heart Association class improvement or survival during follow-up were observed. One patient required reoperation for symptomatic PPM 426 days after implantation. Valve-in-valve implantation can be performed in high-risk surgical patients to avoid reoperation. However, PPM frequently occurs, making adequate patient selection crucial. Small bioprostheses (body surface area less than 1.8 m(2). Larger prostheses seem to carry a lower risk for PPM. Although no delay in clinical improvement was seen at short-term, 1 PPM-related surgical intervention raises concern regarding

Does autoimmunity play a role in the risk of implantation failures?

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Motak-Pochrzest, Hanna; Malinowski, Andrzej

2018-02-01

158 non-pregnant women with recurrent implantation failures after IVF/ET procedures were tested for peripheral blood autoimmune profile. The control group consisted of 76 patients after first successful IVF procedure and pregnancy outcome. The objective of this study was to investigate different autoantibodies peripheral blood profile after excluding anatomical, endocrinological, endometrial and genetic disorders and to estimate the risk of implantation failures. The study's including criteria were 1.indications for IVF/ET determined by male factor and unexplained infertility 2. absence of implantation after two consecutive cycles of IVF, ICSI or frozen embryo replacement cycles. The presence of ANA in the sera increased the risk of RIF after ET/IVF procedures, especially in older patients. Patients with RIF have a higher frequency of the presence of autoantibodies ACA IgG, IgM and anti-β2GP I IgG in the sera than in patients with successful pregnancies after IVF/ET procedures.

Immediate Loading of Tapered Implants Placed in Postextraction Sockets and Healed Sites.

Science.gov (United States)

Han, Chang-Hun; Mangano, Francesco; Mortellaro, Carmen; Park, Kwang-Bum

2016-07-01

The aim of the present study was to compare the survival, stability, and complications of immediately loaded implants placed in postextraction sockets and healed sites. Over a 2-year period, all patients presenting with partial or complete edentulism of the maxilla and/or mandible (healed site group, at least 4 months of healing after tooth extraction) or in need of replacement of nonrecoverable failing teeth (postextraction group) were considered for inclusion in this study. Tapered implants featuring a nanostructured calcium-incorporated surface were placed and loaded immediately. The prosthetic restorations comprised single crowns, fixed partial dentures, and fixed full arches. Primary outcomes were implant survival, stability, and complications. Implant stability was assessed at placement and at each follow-up evaluation (1 week, 3 months, and 1 year after placement): implants with an insertion torque (IT) sockets of 17 patients, and 32 implants were placed in healed sites of 22 patients. There were no statistically significant differences in ISQ values between the 2 groups, at each assessment. In total, 60 implants (96.8%) had an IT ≥45 and an ISQ ≥70 at placement and at each follow-up control: all these implants were successfully loaded. Only 2 implants (1 in a postextraction socket and 1 in a healed site, 3.2%) could not achieve an IT ≥45 N·cm and/or an ISQ ≥70 at placement or over time: accordingly, these were considered failed for stability, as they could not be subjected to immediate loading. One of these 2 implants, in a healed site of a posterior maxilla, had to be removed, yielding an overall 1-year implant survival rate of 98.4%. No complications were reported. No significant differences were reported between the 2 groups with respect to implant failures and complications. Immediately loaded implants placed in postextraction sockets and healed sites had similar high survival and stability, with no reported complications. Further long

Comparative study of manufacturing condyle implant using rapid prototyping and CNC machining

Science.gov (United States)

Bojanampati, S.; Karthikeyan, R.; Islam, MD; Venugopal, S.

2018-04-01

Injuries to the cranio-maxillofacial area caused by road traffic accidents (RTAs), fall from heights, birth defects, metabolic disorders and tumors affect a rising number of patients in the United Arab Emirates (UAE), and require maxillofacial surgery. Mandibular reconstruction poses a specific challenge in both functionality and aesthetics, and involves replacement of the damaged bone by a custom made implant. Due to material, design cycle time and manufacturing process time, such implants are in many instances not affordable to patients. In this paper, the feasibility of designing and manufacturing low-cost, custom made condyle implant is assessed using two different approaches, consisting of rapid prototyping and three-axis computer numerically controlled (CNC) machining. Two candidate rapid prototyping techniques are considered, namely fused deposition modeling (FDM) and three-dimensional printing followed by sand casting The feasibility of the proposed manufacturing processes is evaluated based on manufacturing time, cost, quality, and reliability.

Zirconia Dental Implants: Investigation of Clinical Parameters, Patient Satisfaction, and Microbial Contamination.

Science.gov (United States)

Holländer, Jens; Lorenz, Jonas; Stübinger, Stefan; Hölscher, Werner; Heidemann, Detlef; Ghanaati, Shahram; Sader, Robert

2016-01-01

In recent years, dental implants made from zirconia have been further developed and are considered a reliable treatment method for replacing missing teeth. The aim of this study was to analyze dental implants made from zirconia regarding their clinical performance compared with natural teeth (control). One hundred six zirconia implants in 38 adults were analyzed in a clinical study after 1 year of loading. The plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD), probing attachment level (PAL), and creeping or recession (CR/REC) of the gingiva were detected and compared with natural control teeth (CT). Furthermore, the papilla index (PAP), Periotest values (PTV), microbial colonization of the implant/dental sulcus fluid, and patient satisfaction were assessed. The survival rate was 100%. No statistical significance was observed between implants and teeth regarding BOP, PPD, and PAL. A statistical significance was detected regarding PI and CR/REC with significantly less plaque accumulation and recession in the study group. Mean PAP was 1.76 ± 0.55, whereas the mean PTV was -1.31 ± 2.24 (range from -5 to +6). A non-statistically significant higher colonization of periodontitis/peri-implantitis bacteria was observed in the implant group. The questionnaire showed that the majority of the patients were satisfied with the overall treatment. One-piece zirconia dental implants exhibited similar clinical results (BOP, PPD, and PAL) compared with natural teeth in regard to adhesion of plaque (PI) and creeping attachment (CR/REC); zirconia implants performed even better. The favorable results for PAL and CR/REC reflect the comparable low affinity of zirconia for plaque adhesion. Patient satisfaction indicated a high level of acceptance for zirconia implants. However, a long-term follow-up is needed to support these findings.

A single multilocus sequence typing (MLST) scheme for seven pathogenic Leptospira species

NARCIS (Netherlands)

Boonsilp, Siriphan; Thaipadungpanit, Janjira; Amornchai, Premjit; Wuthiekanun, Vanaporn; Bailey, Mark S.; Holden, Matthew T. G.; Zhang, Cuicai; Jiang, Xiugao; Koizumi, Nobuo; Taylor, Kyle; Galloway, Renee; Hoffmaster, Alex R.; Craig, Scott; Smythe, Lee D.; Hartskeerl, Rudy A.; Day, Nicholas P.; Chantratita, Narisara; Feil, Edward J.; Aanensen, David M.; Spratt, Brian G.; Peacock, Sharon J.

2013-01-01

The available Leptospira multilocus sequence typing (MLST) scheme supported by a MLST website is limited to L. interrogans and L. kirschneri. Our aim was to broaden the utility of this scheme to incorporate a total of seven pathogenic species. We modified the existing scheme by replacing one of the

An overview of recent advances in designing orthopedic and craniofacial implants.

Science.gov (United States)

Mantripragada, Venkata P; Lecka-Czernik, Beata; Ebraheim, Nabil A; Jayasuriya, Ambalangodage C

2013-11-01

Great deal of research is still going on in the field of orthopedic and craniofacial implant development to resolve various issues being faced by the industry today. Despite several disadvantages of the metallic implants, they continue to be used, primarily because of their superior mechanical properties. In order to minimize the harmful effects of the metallic implants and its by-products, several modifications are being made to these materials, for instance nickel-free stainless steel, cobalt-chromium and titanium alloys are being introduced to eliminate the toxic effects of nickel being released from the alloys, introduce metallic implants with lower modulus, reduce the cost of these alloys by replacing rare elements with less expensive elements etc. New alloys like tantalum, niobium, zirconium, and magnesium are receiving attention given their satisfying mechanical and biological properties. Non-oxide ceramics like silicon nitride and silicon carbide are being currently developed as a promising implant material possessing a combination of properties such as good wear and corrosion resistance, increased ductility, good fracture and creep resistance, and relatively high hardness in comparison to alumina. Polymer/magnesium composites are being developed to improve mechanical properties as well as retain polymer's property of degradation. Recent advances in orthobiologics are proving interesting as well. This paper thus deals with the latest improvements being made to the existing implant materials and includes new materials being introduced in the field of biomaterials. Copyright © 2013 Wiley Periodicals, Inc.

Evaluation of mandibular posterior single implants with two different surfaces: a 5-year comparative study.

Science.gov (United States)

Jung, Ui-Won; Choi, Jung-Yoo; Kim, Chang-Sung; Cho, Kyoo-Sung; Chai, Jung-Kiu; Kim, Chong-Kwan; Choi, Seong-Ho

2008-10-01

Anatomic and biomechanical limitations can jeopardize successful single implantation in the mandibular posterior area. To overcome the limitations, the design and the surface of the fixtures were modified. This study evaluated the cumulative survival rate (CSR) of mandibular molars replaced with a sand-blasted, large-grit, acid-etched (SLA) single implant or an anodized (ANO) single implant and examined associated factors, such as the surface treatment, position, and length and diameter of the implants. One hundred ninety-three single implants restored with an SLA implant and 112 single implants restored with an ANO implant in the mandibular molar area were selected from subjects who had visited the Department of Periodontology, Dental Hospital of Yonsei University, from March 2001 through June 2006. In the SLA group, 123 and 70 implants were placed in the first and second molar area, respectively. In the ANO group, 55 and 57 implants were placed in the first and second molar area, respectively. The 1- to 6-year CSR of the SLA and ANO groups was calculated using the life-table analysis. In addition, associated factors, such as the surface treatment, position, and length and diameter of the implants, were compared and analyzed using the chi(2) test (P CSR of 98.96%; four of 112 ANO implants failed, giving a CSR of 96.43%. There were no significant differences with regard to the surface treatment, position, and length and diameter of the implants. Despite the anatomic and biomechanical limitation in the mandibular posterior area, mandibular posterior single implants showed a high CSR during the observation period. Mandibular posterior single implants can be an effective and reliable treatment modality that is not affected by the surface treatment, position, or length and diameter of the implant.

[Pannus Formation Two Years after Bioprosthetic Aortic Valve Implantation;Report of a Case].

Science.gov (United States)

Ono, Kimiyo; Kuroda, Hiroaki

2015-08-01

We report a case of early deterioration of the bioprosthetic aortic valve 23 months postoperatively. A 77-year-old man who had undergone aortic valve replacement with a 23-mm Epic valve( St. Jude Medical [SJM])presented to us after a syncopal episode. Echocardiography revealed severe aortic stenosis, and redo aortic valve replacement with a 21-mm SJM mechanical valve was performed. All 3 cusps of the tissue valve were thickened by fibrous pannus overgrowth. Neither calcification nor invasion of inflammatory cells was observed. The cause of pannus formation at such an early stage after implantation remains unknown.

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.

Experimental and numerical study of cemented bone-implant interface behaviour

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P. Zlamal

2011-01-01

Full Text Available Although the total hip replacement (THR is a long-proven method of surgical treatment of diseases and disorders of the human hip, the surgery brings some risk of long-term instability of the joint. The aim of the research was to investigate the cemented bone-implant interface behavior. The main problems (cement layer degradation and bone-cement interface debonding during physiological loading conditions have been investigated using a custom hip simulator. The experimental setup was designed to allow cyclic loading of the sample of pelvic bone with implanted cemented acetabular component. The hip contact force of required direction and magnitude was applied to the implant using a spherical femoral component head. The most unfavorable activity (downstairs walking was simulated. The process of damage accumulation in the fixation was monitored by repeated scanning using high resolution micro Computed Tomography (µCT. Use of micro-focus source and large high-resolution flat panel detector allows investigation of structural changes and crack propagation both in the cement layer and the trabecular bone.