Search

Objectives: This study aimed to assess the influence of translucent monolithic versus bilayered crowns and whether the use of a CoCr base abutments affects the fatigue and fracture resistance of screwed implant-supported single crowns with external connections under mechanical cycling., Materials and Methods: Fifty specimens were divided into groups: (1) metal-ceramic (MC) crown, (2) veneered zirconia crown (Zr), (3) veneered zirconia crown with a CoCr base abutment (ZrB), (4) monolithic translucent zirconia crown (MZr), and (5) monolithic translucent zirconia crown with a CoCr base abutment (MZrB). Specimens underwent mechanical cycling (5 × 10 6 cycles; 150 N) evaluating fatigue resistance (number of failures) and those that failed were subsequently subjected to fractographic analyses (stereomicroscope and scanning electron microscope) to evaluate failure location and area, and maximum fracture load was also measured., Results: The failure-related survival rate (100%) and maximum fracture resistance of the MZrB were significantly higher than those of MC and Zr (50%; p < 0.05). There were no significant differences in the failure rate and fracture resistance when a CoCr base abutment was used or not in the translucent monolithic Zr groups (p > 0.05;MZrB vs. MZr). Failure location, with MC crowns' fractures, noted at the screw area (p = 0.043), while all-ceramic crowns were mostly in the cuspid and to failure area, the Zr group had the largest mean (15.55 ± 9.17 mm 2 ) among the groups, significant difference only when compared with MC (1.62 ± 0.81 mm 2 ) (p = 0.025)., Conclusions: Translucent monolithic zirconia crowns exhibited significantly higher fatigue and fracture resistance compared with conventional MC and bilayered crowns., Clinical Significance: The appropriate choice of material and manufacturing technique is crucial for predicting the higher clinical performance of single crowns. Enhanced mechanical resistance in terms of fatigue and fracture resistance can be achieved by replacing MC and bilayered restorations with computer-aided design and computer-aided manufacturing monolithic zirconia., (© 2024 Wiley Periodicals LLC.)

Objective: The surgical treatment of Eagle syndrome involves an intra- or extraoral approach. This systematic review set out to consolidate current knowledge on the prevalence of complications associated with intraoral and external approaches., Methods: Seven main electronic and two gray literature databases were searched. Studies were blindly selected by two reviewers based on pre-defined eligibility criteria. Studies evaluating any type of complication in the treatment of Eagle syndrome were considered eligible. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for studies reporting prevalence data, case reports, and case series. The Comprehensive Meta-Analysis software (Software version 3.0 - Biostat, Englewood, NJ, USA) was used to perform all meta-analyses., Results: Out of 1728 articles found on all databases, 36 were included for qualitative analysis. Twenty were included for quantitative analysis and meta-analysis., Conclusion: In this study, the highest rate of complications was found in the intraoral approach.

Purpose: To evaluate the published literature on tooth-tissue supported removable partial dentures (RPDs) and determine the attachment system that provides the best clinical outcome., Materials and Methods: A comprehensive search of studies published up to November 2021 was performed in the PubMed/MEDLINE, Web of Science, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The study protocol was approved and was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42021268449). The PICO question was, 'What is the best attachment system used in Kennedy class I and II removable partial dentures?', Results: The search identified 871 articles, of which 21 met the inclusion criteria. The evaluation period in the studies ranged from 3 to 282 months. A total of 1,357 patients were included, of which 526 used prostheses with attachments. The mini SG attachment (extracoronal) was the most commonly used attachment, and the survival rate ranged from 37% to 98.1% in 10 studies, with no significant differences between the systems. Among the 10 studies selected for quantitative analysis, the meta-analysis revealed an overall failure rate of 16.6% (95% CI: 10.4% to 25.4%) and heterogeneity of I² &#61; 65.725 (q value: 26.258, P &#61; .002)., Conclusions: Clinical studies comparing different attachment systems for rehabilitation are lacking. Our findings suggest that attachment-retained RPDs have good retention and better esthetics than conventional RPDs, and the extracoronal attachment system is the most viable choice for treatment at the free end.

Statement of Problem: Although mandibular implant-supported overdentures have been highly recommended as a treatment option, a consensus on the type of attachment systems that can be used to increase implant and prostheses survivability is lacking., Purpose: The purpose of this systematic review and meta-analysis was to compare different types of attachments for retention by investigating outcome measures such as implant and prosthesis survival rates and biological and prosthesis complications in participants with a mandibular implant-supported overdenture., Material and Methods: The search was performed in the PubMed, Cochrane, Embase, and Scopus databases by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria and registered with the International Prospective Register of Systematic Reviews (CRD42021253566). An analysis of association was conducted between different attachment systems and implant and overdenture survival rates in randomized controlled clinical trials., Results: The initial search indicated 477 studies, of which 25 randomized controlled trials (RCTs) were included for analysis. A total of 2154 implants and 737 overdentures were analyzed in the meta-analysis. The main results indicated the failure rate for dental implants to be 2.0% (95% confidence interval [CI], 1.3 to 3.2) and overdentures 4.2% (95% CI, 1.6 to 10.5), respectively. With regard to different attachment systems, a similar failure rate was identified with bar-type retention (7.7% to 95% CI, 3.0 to 18.1), magnetic retention systems (7.6% to 95% CI, 2.2 to 22.7), and ball-type retention (6.8% to 95% CI, 3.0 to 14.3). No significant difference was found in biological complications for splinted and unsplinted implant overdentures (P=.902). Regarding prosthetic complications, the most favorable groups were LOCATOR attachments followed by telescopic and Conus, bar, and ball attachments. Magnet attachments had higher prosthetic complications (7.4 times) than the other attachments., Conclusions: Implants and implant-supported mandibular overdentures showed a high survival rate irrespective of the attachment system used. Splinting implants did not significantly affect the rate of biological complications. Prosthetic complications were most common for magnet and least common for LOCATOR attachments., (Copyright © 2022 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Reports on the impact of fixed partial denture treatments on the quality of life of patients with cleft lip and palate are lacking., Purpose: The purpose of this cross-sectional clinical study was to assess the impact of fixed partial dentures on the quality of life of adults with cleft lip and palate., Material and Methods: A total of 52 participants (23 women and 29 men) with cleft lip and palate, aged between 20 and 50 years old, and who required treatment with fixed partial dentures were enrolled in the study. They responded to the Oral Health Impact Profile (OHIP)-14 questionnaire before and 30 days after the fixed prosthodontic treatment. The final value from the OHIP-14 was generated by totaling the 14 answers, giving a range from 0 to 56, with higher values indicating a worse relationship between oral health and the quality of life. Nonparametric statistical analysis was performed with the Wilcoxon test (α=.05)., Results: Forty-six participants reported some negative experience before the fixed partial denture, and 48 indicated an improved quality of life 30 days after delivery. All domains assessed showed significant quality of life improvements between the periods compared (P≤.014)., Conclusions: Oral treatment with fixed partial dentures improved the quality of life in adults with cleft lip and palate., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose: To identify and map the scientific evidence regarding factors associated with the nonadaptation of completely edentulous patients to mandibular complete dentures., Materials and Methods: This scoping review followed the PRISMA-ScR statement for Scoping Reviews and was based on guidelines proposed by Arksey and O'Malley and the Joanna Briggs Institute Manual for Evidence Synthesis. The methodology was registered on the Open Science Framework. An electronic search strategy was conducted in PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library, Virtual Health Library, ClinicalTrials.gov, Google Scholar, and ProQuest databases was conducted. Studies that evaluated factors associated with adaptation to and acceptance of mandibular complete dentures were included, such as sociodemographic, psychologic, patient-related, and denture-related items., Results: The search conducted in March 2022 yielded 9,978 studies. In total, 24 studies were included for data extraction. Sociodemographic factors did not interfere with adaptation to a mandibular complete denture. Psychologic factors and patient-related aspects showed greater association with nonadaptation to mandibular complete dentures than denture-reported factors., Conclusion: Although it is suggestive that psychologic and patient-related factors have higher association with the acceptance of new dentures, data must be interpreted with caution due to the variability of methodologies of the studies included in this review.

Statement of Problem: Photodynamic therapy is widely used in dentistry, but limited evidence exists regarding its effectiveness in treating denture stomatitis. High resistance to antifungals has been reported, and photodynamic therapy could be an alternative treatment., Purpose: The purpose of this systematic review and meta-analysis was to evaluate whether photodynamic therapy is effective in reducing denture stomatitis., Material and Methods: A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and recorded in the prospective register of systematic reviews (PROSPERO) (CRD42020205589) to answer the population, intervention, control, outcome (PICO) question: "Is photodynamic therapy effective in the treatment of denture stomatitis when compared with the use of antifungal agents?" Electronic searches were performed in databases PubMed/MEDLINE, Cochrane library, and Web of Science for articles published until February 2021 by using the following terms: (denture stomatitis OR oral candidiasis) AND (low-level light therapy OR laser therapy OR lasers OR photodynamic therapies OR photochemotherapy) AND (antifungal drugs OR antifungal agents OR antimicrobial OR treatment). Clinical trials and randomized clinical trials, studies in the English language, and studies comparing antifungal agents with photodynamic therapy were included., Results: In total, 5 articles were selected for the qualitative analysis and 3 for the meta-analysis. No significant difference was detected between antifungal therapy and photodynamic therapy in the reduction of colony-forming units on the palate. In a subgroup analysis, a significant difference was found in the reduction of colony-forming units on the palate at 15 days and at the denture surface at 30 days., Conclusions: Photodynamic therapy is effective in the treatment of denture stomatitis, but after 30 days and 15 days, the antifungals demonstrated better performance., (Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Background: An edema assessment following dental surgeries is essential to improving the dental surgeon's technique and, consequentially, patient comfort., Purpose: Two-dimensional (2D) methods are limited in analyzing 3-dimensional (3D) surfaces. Currently, 3D methods are used to investigate postoperative swelling. However, there are no studies that directly compare 2D and 3D methods. The goal of this study is to directly compare 2D and 3D methods used in the assessment of postoperative edema., Study Design and Sample: The investigators implemented a prospective, cross-sectional study with each subject serving as its own control. The sample was composed of dental student volunteers without facial deformities., Predictor Variable: The predictor variable is the method used to measure edema. After simulating edema, manual (2D) and digital (3D) techniques were used to measure edema. The manual method used direct facial perimeter measurements. The two digital methods were photogrammetry using a smartphone (iPhone 11, Apple Inc, Cupertino, California), and facial scanning with a smartphone application (Bellus3D FaceApp, Bellus3D Inc, Campbell, California) [3D measurements] MAIN OUTCOME VARIABLE: The coefficient of variation (CV) (CV = standard deviation /mean) was used to assess homogeneity of edema measurements., Analysis: The Shapiro-Wilk and equal variance tests were applied to assess data homogeneity. Next, one-way analysis of variance was performed, followed by a correlation analysis. Finally, the data were submitted to Tukey's test. The statistical significance threshold was set at 5% (P < .05)., Results: The sample was composed of 20 subjects aged 18-38 years. The CV showed higher values using the manual (2D) method (47%; 4.88% ± 2.99), compared with the photogrammetry method (18%; 8.55 mm ± 1.52) and the smartphone application (21%; 8.97 mm ± 1.93). A statistically significant difference was observed between the manual method values and those of the other two groups (P < .001). There was no difference between the facial scanning and photogrammetry groups (3D methods) (P = .778) CONCLUSION AND RELEVANCE: Both digital measuring methods (3D) demonstrated greater homogeneity than the manual method in analyzing facial distortions caused by the same swelling simulation. Therefore, it can be affirmed that digital methods may be more reliable that manual methods for assessing facial edema., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Currently, there is no consensus on the indications and clinical performance of implant-supported overdentures (IODs) involving computer-aided design and manufacturing (CAD-CAM) bars., Objective: To evaluate the performance of IODs involving CAD-CAM bars., Methodology: A comprehensive search of studies published until May 2023 was conducted in many databases, including PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The population, intervention, comparison, outcome (PICO) question was: "How do IODs retained by bars fabricated by CAD-CAM technology perform in daily clinical practice?" The meta-analysis included clinical studies based on effect size and a two-tailed null test with a 95% confidence interval (CI)., Results: Ten studies were included in the meta-analysis. Among them, nine reported a 100% implant survival rate for all CAD-CAM milled bars. Complications were reported in two studies with CAD/CAM-milled titanium bars, and one study reported more fractures in soldered gold bars used in maxillary rehabilitation. However, no fractures were observed in IODs retained by PEEK and zirconia bars. According to six studies, biological complications, including peri-implantitis, were minimal in the BioHPP and PEEK bar groups, while no cases were reported in the titanium or zirconia bar groups. CAD-CAM-milled zirconia bars had higher plaque and bleeding indices compared with titanium bars, as evidenced by findings from five studies. All four studies that evaluated Oral Health Impact Profile (OHIP) scores showed a positive effect of IODs retained by CAD-CAM milled titanium bars on quality of life. Patient satisfaction and acceptance by prosthodontists were significantly high, according to the results of five studies., Conclusion: Overdentures retained with CAD-CAM milled titanium bars show great potential for use in daily clinical practice. Moreover, patient and practitioner satisfaction was very high when this method was used.

Objective: This study aimed to investigate chlorhexidine's efficacy in preventing ventilator-associated pneumonia (VAP)., Design: A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses., Settings: The data were obtained from Pubmed, Cochrane Library, and EMBASE., Patients or Participants: Only mechanically ventilated patients for at least 48h were included., Interventions: Randomized clinical trials applying any dosage form of chlorhexidine were eligible., Main Variables of Interest: The relative risk (RR) of the VAP incidence and all-cause mortality was assessed using the random-effects model. The mean difference in days of mechanical ventilation duration and intensive care unit (ICU) length of stay were also appraised., Results: Ten studies involving 1233 patients were included in the meta-analysis. The oral application of CHX reduced the incidence of VAP (RR, 0.73 [95% CI, 0.55, 0.97]) and did not show an increase in all-cause mortality (RR, 1.13 [95% CI, 0.96, 1.32])., Conclusions: CHX proved effective to prevent VAP. However, a conclusion on mortality rates could not be drawn because the quality of the evidence was very low for this outcome., (Copyright © 2022. Published by Elsevier España, S.L.U.)

Statement of Problem: The introduction of computer-aided design and computer-aided manufacturing (CAD-CAM) technology for complete denture fabrication may have improved clinical outcomes compared with conventional techniques. However, systematic reviews comparing these techniques are lacking., Purpose: The purpose of this systematic review was to identify, compare, and synthesize the outcomes of published clinical studies related to complete denture fabrication, with respect to the differences between CAD-CAM technology and conventional techniques., Material and Methods: A comprehensive search of studies published up to March 16, 2020, was conducted by using the PubMed/MEDLINE, Web of Science, Cochrane Library, SciELO, and Embase databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement criteria and was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID 42020202614). The population, intervention, comparison, and outcome (PICO) question was: Do CAD-CAM complete dentures have a similar functional performance to those fabricated by conventional techniques? The quality of publications was appraised by using the Critical Appraisal Skills Program (CASP) checklists., Results: Of the 1232 titles, 6 articles were selected. The studies reported better retention of digitally manufactured complete dentures without denture adhesives than that of conventional complete dentures with or without denture adhesives. Other studies reported that dentures manufactured with digital systems were better adapted to tissue surfaces, required less clinical time, were lower in cost, and provided better experience and satisfaction to patients., Conclusions: The assessment of CAD-CAM planning and manufacturing through clinical studies is ongoing. However, preliminary results indicate better clinical performance and lower overall costs of digital complete dentures than conventional dentures., (Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Monolithic ceramic implant-supported restorations have been used to rehabilitate partially edentulous patients. However, knowledge of the survival and prosthetic complications of single crowns (SCs) and fixed partial dentures (FPDs) is limited., Purpose: The purpose of this systematic review with meta-analysis was to evaluate the clinical performance of monolithic ceramic implant-supported SCs and FPDs in terms of survival and prosthetic complication rates., Material and Methods: The systematic review was registered on the prospective register of systematic reviews (PROSPERO) (CRD42017078568). Five electronic databases were independently searched by 2 authors for articles published until May 2022. In addition, a hand search was performed in the nonpeer-reviewed literature, specific journals, and reference lists of included articles. A single-arm meta-analysis was performed by using the R program. The risk of bias and quality were assessed using the Cochrane risk of bias tools and the Newcastle-Ottawa scale., Results: Twenty-eight studies were included in the quantitative synthesis. A total of 1298 monolithic ceramic implant-supported restorations (1116 SCs and 182 FPDs) were evaluated in 1193 participants, with a median observation time of 24 months (range: 12 to 72 months). Meta-analysis indicated the proportion of failures and prosthetic complication rates of 2% (95% confidence interval [CI]: 1% to 4%) for SCs. No difference was observed for monolithic zirconia and lithium disilicate SCs. In the FPDs, only monolithic zirconia was considered, with 1 failure reported totaling the proportion of failures of 0% (0% to 1%) and complication rates of 4% (0% to 12%). The most complications reported for both types of restorations were screw loosening, debonding, and minor chipping and were considered repairable. The included studies showed a low risk of bias and good quality., Conclusions: The use of monolithic ceramic implant-supported SCs, independent of ceramic material, and monolithic zirconia implant-supported FPDs should be considered an effective and safe treatment option because of favorable short-term survival and low prosthetic complications. However, additional well-conducted studies with a longer-term follow-up and direct comparison between veneered restorations are recommended to reassess clinical performance., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Denture adhesives are widely used products, but limited evidence regarding their toxicity is available., Purpose: The purpose of this scoping review was to map the existing literature on the toxic potential of denture adhesives., Material and Methods: This scoping review was structured based on the 5-step methodology proposed by Arksey and O'Malley and The Joanna Briggs Institute Manual for Evidence Synthesis and followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. The methods were registered on the Open Science Framework (). The following research question was formulated: Are there any toxic effects related to the use of denture adhesives? The electronic literature search was performed independently by 2 authors in the following databases: PubMed/MEDLINE, Scopus, Web of Science, and the Cochrane Library. The inclusion criteria were in vitro and clinical studies; studies that evaluated the cytotoxic properties of denture adhesives as local or systemic implications; and studies published in English., Results: The search conducted in October 2020 provided 1099 articles. In total, 33 studies were included, 14 in vitro and 19 clinical studies. Commercially available denture adhesives have a dose-dependent cytotoxic effect on fibroblasts and keratinocytes, with poor cell recovery noted in older human fibroblasts. Patients presented different levels of neurologic or hematological alterations associated with the excessive use of denture adhesives., Conclusions: Most commercially available denture adhesives have a dose-dependent cytotoxic effect, and the use of well-adapted removable dental prostheses, proper patient follow-ups, and correct instructions for their use when indicated should be a priority., (Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A consensus that establishes the indications and clinical performance of removable partial denture (RPD) frameworks designed and manufactured with computer-aided design and computer-aided manufacturing (CAD-CAM) systems is lacking., Purpose: The purpose of this systematic review and meta-analysis was to evaluate the currently published literature investigating different CAD-CAM methods and techniques for RPD manufacturing and their clinical performance., Material and Methods: A comprehensive search of studies published up to September 2019 was performed in PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA Statement) criteria and was registered and approved in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42020152197). The population, intervention, comparison, outcome (PICO) question was "Do the CAD-CAM frameworks have similar performances to those fabricated by conventional techniques?" The meta-analysis included clinical and in vitro studies based on the effect size and test of Null (2-Tail) with 95% confidence interval (CI). Clinical and in vitro studies were selected and analyzed separately., Results: A total of 15 articles out of 358 were selected. For clinical studies, quantitative analysis with a sample of 25 participants showed a mean discrepancy between occlusal rests and rest seats of 184.91 μm (95% CI: 152.6 μm-217.15 μm) and heterogeneity (I 2 ) of 0%. Clinical data considered that frameworks were acceptable for continuity of treatment. The predominant materials were cobalt-chromium (Co-Cr) and polyetheretherketone (PEEK), and studies using Co-Cr reported that the structure required adjustments. In addition, it has been reported that the indirect technique was time-consuming and selective laser melting (SLM) can be costly. PEEK structures have been more widely accepted because of improved esthetics. Quantitative data from the in vitro studies revealed that the additive manufacturing technique (2.006 mm: 95% CI: -2.021 mm to 6.032 mm) was not significantly different from the indirect technique (0.026 mm; P=.455; random: I 2 : 98.402%)., Conclusions: Clinical studies and in vitro research on CAD-CAM planning and manufacturing of removable prosthesis frameworks are still sparse. However, preliminary data indicate a similar fit and esthetic improvement when compared with the conventional technique., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Acetylsalicylic acid (ASA) is commonly used as a non-steroidal anti-inflammatory drug that interferes with multiple biological pathways. ASA acts by stimulating osteogenesis and inhibiting osteoclastogenesis. Thus, the objective of this study was to perform a systematic review and meta-analysis to evaluate the effectiveness of the use of ASA in the bone regeneration in animal models. This review was structured based on the PRISMA Statement and registered on PROSPERO database according to protocol number #CDR42018111403. The quality of evidence was assessed by using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE). With the development of search strategies, we identified studies on the use of ASA from the following databases: 1- Medline (via PubMed); 2 - Web of Science; 3 - Scopus; and 4 - EMBASE. A total of 296 articles were identified and after screening the title, abstract, and full text, only 18 studies were selected for qualitative analysis and 12 were selected for performance of the quantitative analysis (meta-analysis). A meta-analysis of the amount of bone tissue formed showed a significant advantage when ASA was locally used, revealing a mean difference (MD) of 22.75% (95% CI: 15.39-30.12) p < 0.00001. Within the limitations of the available data, the results were promising and showed that ASA can be effective in bone formation in animal models., (Copyright © 2020 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: This photoelastic analysis evaluated stress distribution in different osteosynthesis systems, conventional and locking, used for treatment of mandibular angle fractures with a single plate., Material and Methods: Angle fractures were simulated in mandibles made of photoelastic resin. Following Champy's method, plate osteosynthesis was performed. The samples were divided into five groups: Group 1, non-fractured mandible; Group 2, two screws were installed in each segment using a conventional system; Group 3, two screws were installed in each segment using a locking system; Group 4, three screws were installed in the proximal segment and four screws in the distal segment using a conventional plate; Group 5, three screws were installed in the proximal segment and four screws in the distal segment using a locking plate. In an universal testing machine coupled to a polariscope, a load was applied to the first molar 10 times. The 50 images were randomly numbered and analyzed qualitatively and quantitatively by two raters., Results: The locking system promoted better stress distribution along the osteosynthesis. The locking system reduced stress magnitude in the distal segment, with a significant between-group difference ( P ≤ 0.001)., Conclusions: The locking plate/screw system can distribute stress more evenly throughout the osteosynthesis, especially when long seven-hole plates are used. Key words: Internal fracture fixation, osteosynthesis, mandibular fracture, bone plates., Competing Interests: Conflicts of interest The authors have no conflicts of interest to disclose., (Copyright: © 2021 Medicina Oral S.L.)

Objective: In ICU patients on mechanical ventilation (MV), ventilator-associated pneumonia (VAP) is a common infection. However, such infection can be prevented through oral care protocols. The objective of this study was to compare the efficiency of the use of chlorhexidine and oral hygiene protocols (brushing and clinical procedures) with that of the use of chlorhexidine alone (intervention group and control group, respectively) in decreasing the prevalence of VAP in patients ≥ 18 years of age admitted to the ICU and requiring MV., Methods: In this systematic review and meta-analysis, studies were identified through searches of various national and international databases, as well as of the gray literature, and were selected in accordance with eligibility criteria., Results: We evaluated six studies, involving a collective total of 1,276 patients. We classified the risk of bias as low in three studies, high in two, and uncertain in one; among the six risk domains evaluated, a low risk of bias was predominant in five. The results for random risks were similar in terms of direction and statistical magnitude-chi-square = 6.34; risk difference: -0.06 (95% CI: -0.11 to -0.02); I2 = 21%; p = 0.007. There was a decrease in the prevalence of VAP in the intervention group (n = 1,276) included in the meta-analysis., Conclusions: Protocols that include the mechanical removal of oral biofilm in combination with the use of chlorhexidine can reduce the incidence of VAP among ICU patients requiring MV.

Objectives: To investigate the relationship between coronavirus disease 2019 (COVID-19) and obesity in critically ill patients admitted to the intensive care unit (ICU)., Methods: We systematically searched PubMed, SCOPUS, Embase, LILACS, and Web of Science for studies published up to April 27, 2020. The outcome of interest was composite poor outcome, comprising mortality and severe COVID-19. We used a standardized data extraction form to collect information from published reports of eligible studies. Heterogeneity and publication bias were assessed using I 2 statistic and funnel plots, respectively., Results: Nine studies including 6577 patients were selected for evaluation. The COVID-19 patients were 59.80% male and had comorbidities such as hypertension (51.51%), diabetes (30.3%), cardiovascular disease (16.66%), lung disease (15.99%), renal disease (7.49%), cancer (5.07%), and immunosuppression (1.8%). For patients with severe complications, the overall pooled event rates were 56.2% (random; 95% CI: 35.3-75.1; p = 0.015; I 2 = 71.461) for obesity, 23.6% (random; 95% CI: 17.9-30.5; p = 0.000; I 2 = 87.705) for type 2 diabetes, 45.9% (random; 95% CI: 38.0-53.9; p = 0.000; I 2 = 90.152) for hypertension, 20.0% (random; 95% CI: 7.9-42.0; p = 0.000; I 2 = 94.577) for smoking, 21.6% (random; 95% CI: 14.1-31.4%; p = 0.000, I 2 = 92.983) for lung diseases, and 20.6% (random; 95% CI: 15.2-27.5; p = 0.000, I 2 = 85.735) for cardiovascular diseases., Discussion: This systematic review indicated the relationship between obesity, ICU admission, severe COVID-19, and disease progression in patients with COVID-19. Obese patients with hypertension, type 2 diabetes, smoking habit, lung disease, and/or cardiovascular disease should be cared for with increased attention., (Copyright © 2020 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.)

Knowledge about the action of immune system in the recognition of biomaterials has been extremely helpful when it comes about understanding host response and biomaterials' fate in human body. This study aimed to investigate inflammatory response and macrophage polarization during bone healing process of rat's calvaria critical defects using different bone materials in order to evaluate their influence on bone repair and on the quality of the newly formed bone tissue. Eighty male albinus Wistar rats underwent surgical procedure for the confectioning of a 5-mm diameter bone defect in their right parietal bone, and divided in four groups (n = 20 each), according the biomaterial: AG - Control, particulate intramembranous autogenous bone graft, HA/TCP - particulate biphasic calcium phosphate with HA/TCP (60/40), DBB - particulate deproteinized bovine bone, VC - particulate bioactive vitroceramic. After 3, 7, 21, and 45 days, the specimens were removed and prepared for microcomputed tomography (microCT), light and polarized microscopy, immunohistochemical analysis, and histomorphometry. No significant differences were detected considering percentage of leukocytes among the groups and periods, as well as in relation to immunolabeling for inflammatory (M1) and reparative (M2) macrophages. However, immunolabeling for bone marker indicated a delayed osteoblast differentiation in VC group, resulting in a decrease in mineralized bone matrix parameters in this group, revealed by microCT. In addition, AG and HA/TCP presented a satisfactory bone collagenous content. Despite the distinct origins and physicochemical properties of the tested biomaterials, they presented similar immune-inflammatory responses in the present experimental model, influencing bone-related proteins and bone quality, which must be considered according to their use., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The purpose of this in vitro study was to measure the vertical, positive-horizontal, and negative-horizontal misfit (VM, PHM, and NHM, respectively) of the zirconia three-element prosthetic framework, fabricated using different methods, and compare them with conventional fabrication methods (lost-wax casting). Furthermore, this study aimed to evaluate the influence of the misfit values on the biomechanical behavior of the 3-unit fixed prosthetic frameworks using three-dimensional finite element analysis (3D-FEA). Forty frameworks (n = 10) were fabricated as follow: G1, Cerec Bluecam; G2, iTero; G3, 3Series; and G4, conventional method. The samples were randomized to measure marginal misfit using a high-precision three-dimensional (3D)-optical microscope. The results were submitted to analysis of variance (ANOVA), with the significance level set at 5%. The mean VM values of each group were used in creating the models by 3D-FEA with the misfit found in optical microscopy. The programs used were the InVesalius, Rhinoceros, SolidWorks, FEMAP and NEiNastran. The von Mises map was plotted for each model. The G4 showed the lowest mean VM value (16.73 μm), followed by G3 (20.71 μm), G2 (21.01 μm), and G1 (41.77 μm) (p < 0.001). G2 was more accurate than G1 (p < 0.05) and similar to G3 (p = 0.319). For PHM, G4 was the most accurate and did not present overextended values. With regard to NHM, the computer-aided design and computer-aided manufacturing (CAD-CAM) systems were more accurate (-61.91 μm) than G4 (-95.36 μm) (p = 0.014). In biomechanical analysis, stress concentration caused by oblique loading is greater than caused by axial loading. In axial loading, G4 was the most favorable while G1 was the least favorable, biomechanically, in oblique loading, similar stress patterns were observed in all the models. The prosthetic screw was the most overloaded structure, but the material did not influence the stress distribution. The misfit prostheses showed a greater degree of stress than the controls (without misfit). The manufacturing method influenced the marginal misfit of the frameworks, with the conventional method being the most accurate and the Cerec Bluecam System (closed system) the least accurate. Biomechanically, fitting prostheses were more favorable than misfit prostheses., (Copyright © 2019. Published by Elsevier B.V.)

Objectives: To follow healing process of augmented maxillary sinus in rabbits analyzing the histological pattern of bone tissue formation, along with the osteogenic activity and vascularization using a bioactive vitroceramic in comparison to deproteinized bovine bone associated or not with autogenous bone graft., Design: Forty five male adult New Zealand rabbits, 5 months of age, mean weight of 4 Kg, underwent bilateral sinus augmentation surgeries to be divided in five groups: G - (Control) particulate autogenous bone graft (AG), BO - deproteinized bovine bone, BO+G - deproteinized bovine bone + AG, BSi -vitroceramic, and BSi + G - vitroceramic +AG. After 15, 45 and 90 days, all animals were euthanized for specimen's removal to be analyzed under light microscopy, histomorphometry, and immunohistochemistry for Runx2 and VEGF labeling., Results: G, BO and BO+G groups healed uneventfully, allowing the formation of mature remodeling bone at day 90, regarding the association of AG with the biomaterial. On the other hand, BSi and BSi + G groups showed an important cellular reaction and granulation/fibrous tissue formation from the first to the last period of observation. Runx-2 and VEGF immunolabeling were coherent with this result. However, histomorphometry did not reveal significant differences considering new bone formation., Conclusions: Reconstructed maxillary sinuses using Biosilicate® permitted satisfactory new bone formation in comparison to the deproteinized bovine bone and AG. However, the presence of granulation/fibrous tissue and inflammatory cells associated to the degrading biomaterial indicate that further studies should be careful performed considering the immunological aspect of this new biomaterial., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Statement of Problem: Consensus is lacking regarding the optimal number of implants for supporting complete-arch prostheses with good survival rates and lower prosthetic complications and marginal bone loss., Purpose: The purpose of this systematic review was to evaluate the influence of the number of implants used for complete-arch prostheses with at least 5 years of follow-up., Material and Methods: A search was performed in the PubMed/MEDLINE, Scopus, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and was registered in The International Prospective Register of Systematic Reviews (CRD42016048468). The following was the population, intervention, comparison, outcome (PICO) question: Does the number of implants influence the longevity of complete-arch prostheses?, Results: Nineteen studies including 1006 patients with a mean age of 61.44 years were selected for evaluation. The number of implants per jaw ranged between 2 and 9 in the maxilla, mandible, or both jaws. For implant survival rate in complete-arch prostheses with fewer than 5 implants per jaw, the pooled weighted event rate was 1.4% (I 2 =25.26%; P=.211) and 4.2% (I 2 =81.35%; P<.001) for complete arches with more than 4 implants per jaw. For the prosthesis survival rate, the pooled weighted event rate for a complete-arch with fewer than 5 implants per jaw was 1.5% (I 2 =0%; P=.677) and 9% (I 2 =17.33%; P=.304) for complete arches with more than 4 implants per jaw. For prosthesis complications for complete arches with fewer than 5 implants per jaw, the pooled weighted event rate was 19.9% (I 2 =93.5%; P<.001) and 24.5% (I 2 =88.89; P<.001) for complete arches with more than 4 implants per jaw. The mean marginal bone loss for complete arches with fewer than 5 implants per jaw was 1.22 ±0.49 mm (I 2 =99.46; P<.001) and 1.46 ±0.46 mm (I 2 =99.6; P <.001) for more than 4 implants per jaw., Conclusions: The current systematic review indicated no relationship of the number of implants used to support a complete-arch prosthesis with implant survival rate, prosthesis survival rate, prosthesis complications, or marginal bone loss in studies with follow-up periods of between 5 and 15 years., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Dental implants provide a predictable treatment option for partial and complete edentulism via the placement of a fixed permanent artificial root to support prosthetic dental crowns. Despite the high survival rates, long-term dental implant failures are still reported, leading to implant removals and additional financial and health burdens. While extrinsic factors that improve the success rate of implants have been well explored, the impact of genetic factors on this matter is poorly understood. A systematic review and meta-analysis study was conducted to determine whether genetic factors contribute to an increased risk of dental implant failures. A comprehensive search for peer-reviewed articles on dental implants and genetic factors was performed using various literature database libraries. The study design was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, and the obtained records were registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. According to the exclusion/inclusion criteria, 13 studies were eligible for this study out of 809 articles. The meta-analysis of the combined association studies of DNA variations and dental implants did not indicate an increased risk for implant failure due to DNA variations in IL-1B , IL-10 and TNF-α . This study emphasizes the need for larger randomized controlled clinical trials to inform clinicians and patients about the role of genetic factors on dental implant survival and the success rate in healthy and compromised patients.

The aim of this study was to evaluate stress distribution in the implants/components and bone tissue for splinted and nonsplinted prostheses with different lengths of implants using three-dimensional finite element analysis. Six models from the posterior maxillary area were used in simulations. Each model simulated three Morse taper implants of 4.0 mm diameter with different lengths, which supported metal-ceramic crowns. An axial load of 400 N and an oblique load of 200 N were used as loading conditions. Splinted prostheses exhibited better stress distribution for the implants/components, whereas nonsplinted prostheses exhibited higher stress in the first molar under axial/oblique loading. Implant length did not influence stress distribution in the implants/components. In cortical bone tissue, splinted prostheses decreased the tensile stress in the first molar, whereas nonsplinted prostheses were subjected to higher tensile stress in the first molar; implant length had no influence on stress distribution. Within the limitations of this study, we conclude that splinted prostheses contributed to better stress distribution in the implant/abutment and cortical bone tissue; however, the reduction in the implant length did not influence the stress distribution.

Background: An efficient orthodontic treatment must aim the best occlusal result in the shortest possible time. One of the factors that can interfere in this goal is the bracket debonding during the treatment. This study aimed at assessing the different factors related to brackets failure, highlighting age and patient cooperation with treatment., Methods: The sample comprised 199 orthodontic patients of both genders (103 women and 96 men); divided into two groups-adolescents (12 to 18 years old, 118 patients) and adults (19 to 59 years old, 81 patients). A questionnaire was applied regarding the motivation of patients to seek treatment and whether they had received information on appliance care; patients also filled out their level of cooperation with treatment in a visual analog scale (VAS). Additionally, other variables were assessed, such as the teeth with bracket debonding, the presence of deep overbite, and the use of bite plate. The Mann-Whitney test was used, and a 5% significance level was applied for analyses., Results: It was observed that 20.1% of patients presented at least one tooth with bracket failure, and the lower arch was the most prevalent site (47.5%). Adolescents presented more debonding (25.4%) than adults (12.3%). Individuals with better VAS scores on cooperation sought treatment on their own (p = 0.042), were adults (p ≤ 0.001), and showed lower rate of failure of brackets (p ≤ 0.001). The factors related to malocclusion and treatment performed had no statistical significance., Conclusion: Greater cooperation was expected from adult individuals who sought treatment on their own and presented low rate of bracket failure.

There is currently no consensus regarding the survival rate of osseointegrated implants in patients with osteoporosis. A systematic review with meta-analysis was performed to evaluate the survival rate of implants in such patients. The PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases were used to identify articles published up to September 2016. The systematic review was performed in accordance with PRISMA/PICO requirements and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk (RR) of implant failure and mean marginal bone loss were analyzed within a 95% confidence interval (CI). Fifteen studies involving 8859 patients and 29,798 implants were included. The main outcome of the meta-analysis indicated that there was no difference in implant survival rate between patients with and without osteoporosis, either at the implant level (RR 1.39, 95% CI 0.93-2.08; P=0.11) or at the patient level (RR 0.98, 95% CI 0.50-1.89; P=0.94). However, the meta-analysis for the secondary outcome revealed a significant difference in marginal bone loss around implants between patients with and without osteoporosis (0.18mm, 95% CI 0.05-0.30, P=0.005). Data heterogeneity was low. An increase in peri-implant bone loss was observed in the osteoporosis group. Randomized and controlled clinical studies should be conducted to analyze possible biases., (Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Statement of Problem: Slight offset of the central implant in 3-unit implant-supported prostheses has been reported to improve biomechanical behavior. However, studies that assessed the effects of an offset implant configuration in the posterior maxilla are scarce., Purpose: The purpose of this 3-dimensional (3D) finite element analysis was to assess the effects of splinting in 3-unit implant-supported prostheses with varying implant positions (straight-line or offset configuration) in terms of the stress/strain distribution on bone tissue and the stress distribution on abutment screws., Material and Methods: Three 3D models were used to simulate a posterior maxilla bone block (type IV): straight-line implants supporting single crowns (model M1), straight-line implants supporting 3-unit splinted fixed dental prosthesis (model M2), and an offset implant configuration supporting 3-unit splinted fixed dental prosthesis (model M3). The applied forces were 400 N axially and 200 N obliquely. The type of implant platform simulated was an external hexagon. von Mises stress on the abutment screws was measured, and the maximum principal stress and microstrain values were used to perform cortical bone tissue analysis. Analysis of variance (ANOVA) and the Tukey honest significant differences post hoc test were used to determine the significance of the results and interactions among the main variables (α=.05)., Results: In all models, oblique load increased the stress on abutment screws and bone tissue and the microstrain on bone tissue. Model M3 decreased the stress concentration on the abutment screws and bone tissue. With regard to microstrain distribution, model M3 had the smallest values, and M1 and M2 had similar values., Conclusions: Splinting associated with an offset implant configuration was effective for decreasing the stress on abutment screws and bone tissue and the microstrain on bone tissue., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the influence of pontic and cantilever designs (mesial and distal) on 3-unit implant-retained prosthesis at maxillary posterior region verifying stress and strain distributions on bone tissue (cortical and trabecular bones) and stress distribution in abutments, implants and fixation screws, under axial and oblique loadings, by 3D finite element analysis. Each model was composed of a bone block presenting right first premolar to the first molar, with three or two external hexagon implants (4.0 × 10 mm), supporting a 3-unit splinted dental fixed dental prosthesis with the variations: M1 - three implants supporting splinted crowns; M2 - two implants supporting prosthesis with central pontic; M3 - two implants supporting prosthesis with mesial cantilever; M4 - two implants supporting prosthesis with distal cantilever. The applied forces were 400 N axial and 200 N oblique. The von Mises criteria was used to evaluate abutments, implants and fixation screws and maximum principal stress and microstrain criteria were used to evaluate the bone tissue. The decrease of the number of implants caused an unfavorable biomechanical behavior for all structures (M2, M3, M4). For two implant-supported prostheses, the use of the central pontic (M2) showed stress and strain distributions more favorable in the analyzed structures. The use of cantilever showed unfavorable biomechanical behavior (M3 and M4), mainly for distal cantilever (M4). The use of three implants presented lower values of stress and strain on the analyzed structures. Among two implant-supported prostheses, prostheses with cantilever showed unfavorable biomechanical behavior in the analyzed structures, especially for distal cantilever.

The aim of this study is to assess the effect of different dental implant designs, bone type, loading, and surface treatment on the stress distribution around the implant by using the 3D finite-element method. Twelve 3D models were developed with Invesalius 3.0, Rhinoceros 4.0, and Solidworks 2010 software. The analysis was processed using the FEMAP 10.2 and NeiNastran 10.0 software. The applied oblique forces were 200 N and 100 N. The results were analyzed using maps of maximum principal stress and bone microstrain. Statistical analysis was performed using ANOVA and Tukey's test. The results showed that the Morse taper design was most efficient in terms of its distribution of stresses (p<0.05); the external hexagon with platform switching did not show a significant difference from an external hexagon with a standard platform (p>0.05). The different bone types did not show a significant difference in the stress/strain distribution (p>0.05). The surface treatment increased areas of stress concentration under axial loading (p<0.05) and increased areas of microstrain under axial and oblique loading (p<0.05) on the cortical bone. The Morse taper design behaved better biomechanically in relation to the bone tissue. The treated surface increased areas of stress and strain on the cortical bone tissue., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Objective: The aims of this study were to examine the trans- and postoperative systemic characteristics of patients undergoing dental implant surgery and to investigate the relationship between pre- and post- surgery anxiety levels., Material and Methods: Thirty-nine patients were analyzed in 3 call centers to determine anxiety levels, pain levels, and preoperative and postoperative histories using the State-Trait (STAI) questionnaire., Results: A total of 93 dental implants were installed, with a success rate of 100%. The most frequently reported systemic disease was hypertension. There was a significantly higher rate of effective clamping (torque) to the mandibular bone than to the maxillary bone. The association between postoperative surgical complications and longer operative time was not significant, but there was a significant correlation between the alteration of mouth opening and daily routine activities and a significant decrease in anxiety levels between the day of surgery and the postoperative time point (p =0.006)., Conclusion: A longer surgical time was associated with surgery-related complications and with a higher anxiety index on the preoperative evaluation.

Purpose: The purpose of this study was to evaluate the marginal adaptation of fixed dental prosthesis frameworks fabricated by computer-aided design/computer-assisted manufacture (CAD/CAM) with three different systems of data acquisition., Materials and Methods: A total of 50 specimens were fabricated as follows: using the conventional method (Ni-Cr) (n=10); iTero/industrial milling (Group 1, n=10); Cerec Bluecam/industrial milling (Group 2, n=10); 3S/industrial milling (Group 3, n=10); and Cerec BlueCam/Sirona milling (Group 4, n=10). The specimens were numbered and randomized, and the vertical marginal discrepancy was analyzed., Results: Intraobserver analysis indicated no statistically significant difference (paired t test, P=.822) between periods before and after analysis. The conventional method (321 μm) showed greater discrepancy when compared with the CAD/CAM system (89 μm) (P<.001). The intraoral system showed a lower rate of marginal discrepancy when compared with the extraoral system (3S) (P<.001). The closed system presented a higher marginal discrepancy (114 μm) than the open intraoral system (iTero) at P<.001. In addition, the intraoral system when open showed statistically significant differences in mean marginal discrepancy values compared with the same system in closed condition (P>.05)., Conclusion: The CAD/CAM systems showed less marginal discrepancy than the conventional method for the fabrication of the frameworks.

The aim of this study was to analyze the stress distribution of short implants supporting single unit or splinted crowns by the photo-elasticity method. Four photo-elastic models were produced: A (3.75×7 mm); B (3.75×7 mm, 3.75×7 mm and 3.75×7 mm); C (3.75×10 mm, 3.75×7 mm and 3.75×7 mm); D (3.75×13 mm, 3.75×7 mm and 3.75×7 mm). The prostheses were made with Ni-Cr alloy. A load of 100 N in the axial and oblique directions was applied, totaling 380 applications, individually capturing their images in each model. The data were randomized and analyzed qualitatively and quantitatively by 2 examiners. The oblique loading was significantly more damaging. The increase in length was favorable for stress distribution (p<0.05). The splinting was beneficial for the transmission of stresses mainly (p<0.05). The splinting of the crowns, as well as increasing the length of the first implant and axial loading was most beneficial in the stress distribution. Short splinted implants behaved better than single unit implants. Increasing of the length of the first implant significantly improved the stress distribution in all analyzed situations., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Purpose: The aim of this systematic review was to compare straight-line and offset implant configurations for three-element implant-retained prostheses., Materials and Methods: Two independent reviewers conducted a review on PubMed/Medline, EMBASE, and Cochrane Library for studies published in English, from January 1, 1995 to January 17, 2014. A systematic review was conducted following the PRISMA statement. All relevant titles were selected according to inclusion/exclusion criteria. From this pool of titles, abstracts and full texts were reviewed., Results: A total of 6080 titles were identified with the initial search. Twenty-one were selected based on title and abstract. Of these, after discussion and complete reading, 12 studies were selected according to the inclusion and exclusion criteria, all of which were in vitro studies., Conclusions: A systematic review of the current literature showed only in vitro evidence that there is no consensus on the advantage of using an offset configuration implant compared to those in straight-line configuration, even though some studies present a slight improvement of bone stress distribution when an offset implant is under oblique loading (PICO)., (© 2014 by the American College of Prosthodontists.)

The study of short implants is relevant to the biomechanics of dental implants, and research on crown increase has implications for the daily clinic. The aim of this study was to analyze the biomechanical interactions of a singular implant-supported prosthesis of different crown heights under vertical and oblique force, using the 3-D finite element method. Six 3-D models were designed with Invesalius 3.0, Rhinoceros 3D 4.0, and Solidworks 2010 software. Each model was constructed with a mandibular segment of bone block, including an implant supporting a screwed metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm. The applied force was 200 N (axial) and 100 N (oblique). We performed an ANOVA statistical test and Tukey tests; p<0.05 was considered statistically significant. The increase of crown height did not influence the stress distribution on screw prosthetic (p>0.05) under axial load. However, crown heights of 12.5 and 15 mm caused statistically significant damage to the stress distribution of screws and to the cortical bone (p<0.001) under oblique load. High crown to implant (C/I) ratio harmed microstrain distribution on bone tissue under axial and oblique loads (p<0.001). Crown increase was a possible deleterious factor to the screws and to the different regions of bone tissue., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this study was to evaluate the stress distribution on bone tissue with a single prosthesis supported by implants of large and conventional diameter and presenting different veneering materials using the 3-D finite element method. Sixteen models were fabricated to reproduce a bone block with implants, using two diameters (3.75×10 mm and 5.00×10 mm), four different veneering materials (composite resin, acrylic resin, porcelain, and NiCr crown), and two loads (axial (200 N) and oblique (100 N)). For data analysis, the maximum principal stress and von Mises criterion were used. For the axial load, the cortical bone in all models did not exhibit significant differences, and the trabecular bone presented higher tensile stress with reduced implant diameter. For the oblique load, the cortical bone presented a significant increase in tensile stress on the same side as the loading for smaller implant diameters. The trabecular bone showed a similar but more discreet trend. There was no difference in bone tissue with different veneering materials. The veneering material did not influence the stress distribution in the supporting tissues of single implant-supported prostheses. The large-diameter implants improved the transference of occlusal loads to bone tissue and decreased stress mainly under oblique loads. Oblique loading was more detrimental to distribution stresses than axial loading., (© 2013.)

Osteoporosis is a systemic disorder characterized by generalized decrease in bone mineral density. Dental implantology is a specialty with high predictability when both quantity and quality of the bone are respected. Therefore, the diagnosis and the implant treatment in patients with osteoporosis are important. In the current study, a literature review about osteoporosis and dental implant therapy was conducted. PubMed, Cochrane, ISI, Dentistry Oral Science, SciELO, and Bireme databases were consulted over the last 20 years. English- and Portuguese-language articles were included in this revision. Some authors stated that the osteoporotic bone is similar to the proposed model of bone type IV. Randomized clinical studies reported implant failure in patients with osteoporosis after menopause. Studies that contraindicate the use of implants in patients with osteoporosis infer that the impaired bone metabolism led to reduction of bone healing around the implants. Nevertheless, other authors believe that the presence of osteoporosis is not a definitive condition to contraindicate the therapy with dental implants. In these cases, the dentist should perform a proper treatment planning, modifying the implant geometry, and use larger implant diameter and with surface treatment. Thus, osteoporosis is not a contraindication for implant surgery because an accurate analysis of bone quality by means tomography is performed.