Magnetic resonance imaging for jawbone assessment: a systematic review.

PURPOSE: To evaluate the accuracy of magnetic resonance imaging (MRI) for jawbone assessment compared to reference-standard measurements in the literature. MATERIALS AND METHODS: An electronic database search was conducted in PubMed, EMBASE, Scopus, Web of Science, and the Cochrane Library in June 2022, and updated in August 2023. Studies evaluating the accuracy of MRI for jawbone assessment compared with reference-standard measurements (histology, physical measurements, or computed tomography) were included. The outcome measures included bone histomorphometry and linear measurements. The risk of bias was assessed by the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). The review was registered in the PROSPERO database (CRD42022342697). RESULTS: From 63 studies selected for full-text analysis, nine manuscripts were considered eligible for this review. The studies included assessments of 54 participants, 35 cadavers, and one phantom. A linear measurement error ranging from 0.03 to 3.11 mm was shown. The accuracy of bone histomorphometry varies among studies. Limitations of the evidence included heterogeneity of MRI protocols and the methodology of the included studies. CONCLUSION: Few studies have suggested the feasibility of MRI for jawbone assessment, as MRI provides comparable results to those of standard reference tests. However, further advancements and optimizations are needed to increase the applicability, validate the efficacy, and establish clinical utility of these methods.

Cumulative success rate and marginal bone loss for immediate and early loading protocols in a single implant-supported crown: A randomized controlled split-mouth clinical trial.

STATEMENT OF PROBLEM: New loading protocols with reduced treatment time have gained popularity because of their advantages. However, whether the success rate with immediate loading (IL) is worse than with early loading (EL) is still unclear. PURPOSE: The purpose of this randomized controlled trial with a split-mouth design was to evaluate the marginal bone loss and the cumulative success rate (CSR) 1 year after an IL protocol in single implant-supported crowns. The test groups were loaded after less than 24 hours (test group) and EL at 60 days (control group). MATERIAL AND METHODS: Seventeen participants received 34 implants. The recall appointments were at baseline, 30 days, 60 days, and 1 year. The outcome measures evaluated were pain, implant clinical mobility, probing depth measurements, peri-implant disease, marginal bone loss, implant insertion torque, implant stability quotient (ISQ) value, and the CSR. A 2-way repeated measures ANOVA identified the significant differences for probing depth and ISQ. A 3-way repeated measures ANOVA followed by a pairwise t test analyzed marginal bone loss, and a nonparametric Wilcoxon test analyzed insertion torque (α=.05). RESULTS: No differences were found between the insertion torque, ISQ, and marginal bone loss values (P>.05). When analyzing probing depth, no differences were found when comparing IL versus EL at baseline, 30 days, and 1 year (P>.05). The global CSR was 91.17%, 88.23% for the IL group and 94.11% for the EL group. CONCLUSIONS: When analyzing marginal bone loss, the groups were similar. The global CSR was 91.17%, 88.23% for the IL group, and 94.11% for the EL group.

Quality of life assessment in patients with temporomandibular disorder with stabilization splints and home therapeutic exercises: a randomized clinical trial / Avaliação da qualidade de vida em pacientes com desordem temporomandibular com uso da placa estabilizadora e exercícios terapêuticos caseiros: um ensaio clínico randomizado

Objective: The present study aimed to evaluate the quality of life in TMD patients with the use of Stabilization Splints (SSs) and Home Therapeutic Exercises (HTEs) guidance. Material and Methods: The study was a clinical, randomized, controlled, prospective, and interventional trial. The screening included dentate patients of both genders, diagnosed with TMD through the RDC/TMD questionnaire with no TMJ osteoarthritis and/or osteoarthrosis. To assess the quality of life, the Short-Form Health Survey (SF-36) questionnaire was applied to all patients (n=70), randomized into a test group with SS and a control group with HTE. The evaluations of both questionnaires were performed before and after the intervention of 12 weeks. Results: The comparisons between pre- and post-intervention intragroups were performed by the non-parametric Wilcoxon test with a 5% significance level. There was a frequency distribution of the responses to the 36 items of the SF-36 questionnaire and comparisons between times. In the test group, 49 patients received a SS and did HTEs. In the control group, 21 patients performed HTEs. In the statistical analysis, among the eight domains, three were identified with significant scores: pain, mental health, and vitality. Conclusion: It was found that there was an improvement in pain and quality of life after the treatment of TMD with a SS and HTE (AU)

Objetivo: O presente estudo teve como objetivo avaliar a qualidade de vida em pacientes com DTM com o uso de placas de estabilização (SSs) e orientação de exercícios terapêuticos domiciliares (HTEs). Material e Métodos: O estudo foi um ensaio clínico, randomizado, controlado, prospectivo e intervencionista. A triagem incluiu pacientes dentados de ambos os sexos, diagnosticados com DTM através do questionário RDC/TMD sem osteoartrite e/ou osteoartrose da ATM. Para avaliar a qualidade de vida, o questionário Short-Form Health Survey (SF-36) foi aplicado a todos os pacientes (n=70), randomizados em grupo teste com SS e grupo controle com HTE. As avaliações de ambos os questionários foram realizadas antes e após a intervenção de 12 semanas. Resultados:As comparações intragrupos pré e pós-intervenção foram realizadas pelo teste não paramétrico de Wilcoxon com nível de significância de 5%. Houve distribuição de frequência das respostas aos 36 itens do questionário SF-36 e comparações entre os tempos. No grupo controle, 21 pacientes realizaram HTEs. Na análise estatística, dentre os oito domínios, três foram identificados com escores significativos: dor, saúde mental e vitalidade. Conclusão: Verificou-se que houve melhora da dor e da qualidade de vida após o tratamento da DTM com SS e HTE.(AU)

Stress distribution analysis in anterior teeth caused by several retraction mechanics.

INTRODUCTION: Orthodontic retraction of the anterior teeth is indicated when the patient has a malocclusion with protrusion of the incisors. Several mechanics are indicated to perform this retraction. OBJECTIVE: The objective of this study was to compare the strains generated by four different types of retraction mechanics along the roots of the anterior teeth. METHODS: A photoelastic model simulating an arch with first premolars extraction was made. Sixty retraction archwires were prepared, including fifteen for each type of mechanics evaluated: sliding, teardrop loop spring, T-loop spring and double key loop archwire. The strains were observed in two perspectives: occlusal and oblique. In the occlusal perspective, strains were compared among the six anterior teeth. From the oblique perspective, strains were compared among the thirds of the left canine root. RESULTS: In the occlusal perspective, the teardrop loop spring mechanics presented greater strains, followed by T-loop spring, double key loop archwire and sliding mechanics. In all mechanics, strains were more concentrated in the canines than in the incisors. From the oblique perspective, the teardrop loop mechanics generated greater strains in the cervical regions of the canine, and in the apical regions, no differences were found in strains among the four types of mechanics. In the same mechanics, greater strains were present in the cervical zones. CONCLUSION: The teardrop loop spring retraction mechanic presented the greatest mean strain, and the sliding retraction mechanic presented the lowest mean strain on the root of anteroinferior teeth in the occlusal and oblique perspectives.

Stress distribution analysis in anterior teeth caused by several retraction mechanics

ABSTRACT Introduction: Orthodontic retraction of the anterior teeth is indicated when the patient has a malocclusion with protrusion of the incisors. Several mechanics are indicated to perform this retraction. Objective: The objective of this study was to compare the strains generated by four different types of retraction mechanics along the roots of the anterior teeth. Methods: A photoelastic model simulating an arch with first premolars extraction was made. Sixty retraction archwires were prepared, including fifteen for each type of mechanics evaluated: sliding, teardrop loop spring, T-loop spring and double key loop archwire. The strains were observed in two perspectives: occlusal and oblique. In the occlusal perspective, strains were compared among the six anterior teeth. From the oblique perspective, strains were compared among the thirds of the left canine root. Results: In the occlusal perspective, the teardrop loop spring mechanics presented greater strains, followed by T-loop spring, double key loop archwire and sliding mechanics. In all mechanics, strains were more concentrated in the canines than in the incisors. From the oblique perspective, the teardrop loop mechanics generated greater strains in the cervical regions of the canine, and in the apical regions, no differences were found in strains among the four types of mechanics. In the same mechanics, greater strains were present in the cervical zones. Conclusion: The teardrop loop spring retraction mechanic presented the greatest mean strain, and the sliding retraction mechanic presented the lowest mean strain on the root of anteroinferior teeth in the occlusal and oblique perspectives.

RESUMO Introdução: A retração ortodôntica dos dentes anteriores é indicada quando o paciente apresenta má oclusão com vestibularização dos incisivos. Diferentes mecânicas são indicadas para realizar essa retração. Objetivo: O objetivo do presente estudo foi comparar as tensões geradas por quatro diferentes tipos de mecânicas de retração nas raízes dos dentes anteriores. Métodos: Um modelo fotoelástico foi confeccionado simulando uma arcada com os primeiros pré-molares extraídos. Foram preparados 60 arcos de retração, sendo quinze para cada tipo de mecânica avaliada: deslizamento, alça de Bull, alça em T e arco de dupla chave. As tensões foram observadas em duas perspectivas: oclusal e oblíqua. Na vista oclusal, as tensões foram comparadas entre os seis dentes anteriores. Na vista oblíqua, as tensões foram comparadas entre os terços radiculares do canino esquerdo. Resultados: Na vista oclusal, a mecânica com alça de Bull apresentou maiores tensões, seguida da alça em T, arco de dupla chave e mecânica de deslizamento. Em todas as mecânicas, as tensões se concentraram mais nos caninos do que nos incisivos. Na vista oblíqua, a mecânica com alça de Bull gerou maiores tensões nas regiões cervicais dos caninos; nas regiões apicais, não houve diferenças nas tensões entre os quatro tipos de mecânicas. Dentro de uma mesma mecânica, as maiores tensões estiveram presentes nas regiões cervicais. Conclusão: A mecânica de retração com alça de Bull apresentou a maior média de tensões, e a mecânica de retração por deslizamento apresentou a menor média de tensões na raiz dos dentes anteroinferiores, nas vistas oclusal e oblíqua.

Clinical efficiency and patient preference of digital and conventional workflow for single implant crowns using immediate and regular digital impression: A meta-analysis.

OBJECTIVE: To assess whether digital workflow gives better results than the conventional one in the single implant crowns, when analyzing the impression time, patient preference, time efficiency, and adjustment time. MATERIAL AND METHODS: MEDLINE, Embase, and Cochrane were searched and supplemented via hand search up to June 19, 2019. Only clinical trials assessing conventional versus digital workflows for single implant crowns were included. Impression time was evaluated using random effects meta-analysis, while patient preference, adjustment time, and time efficiency were reported descriptively. RESULTS: Among 1,334 publications identified, ten studies were included. The random effects models revealed statistically significant reduction in time in the digital impression group when compared to the conventional group by the mean meta-analysis (MD: 8.22 [95% CI: 5.48, 10.96]). Analysis from immediate digital impression versus conventional (MD: 3.84 [95% CI: 3.30, 4.39]) and regular digital impression versus conventional (MD:10.67 [95% CI: 5.70, 15.65]) showed statistically significant reduction in time on using the digital impression. Impression time in the digital process ranged between 6 min 39 s and 20 min, whereas for conventional, it was between 11.7 and 28.47 min. Patients showed greater preference for digital impression. Adjustment time in the digital process ranged between 1.96 and 14 min, whereas for conventional, it was between 3.02 and 12 min. Time efficiency in the digital process ranged between 36.8 and 185.4 min, whereas for conventional, it was between 55.6 and 332 min. CONCLUSION: The digital workflow has demonstrated better clinical efficiency considering impression time, patient preference, and time efficiency. According to the adjustment time, different results were presented.

Auxiliary Reflectance Sensor for Guided Surgery with Dental Implants: In Vitro Study.

OBJECTIVES: The aim of this research was to develop a sensor of approximation by reflectance for guided surgery with dental implants without flap detachment, and verify the effectiveness of this system. MATERIALS AND METHODS: Ten models of total edentulous arches were divided into two groups. Two implants of 3.5 × 11.5 mm (NeoDent) were inserted in each model; in Group 1 (G1), a stereolithographic guide NeoGuide system was used. In Group 2 (G2), the experimental approximation sensor was used for the insertion of the implants. The evaluation of the results was performed by overlapping the virtual planning images with the tomographies of the models of the implants inserted. RESULTS: There were no statistically significant differences between the guide and the sensor groups. The averages and standard deviations observed at the angulation of the guide was 4.15 (2.65 degrees) and 5.48 (2.85 degrees) at the sensor. The linear deviations at the cervical level were 0.002 (1.37) and 0.11 (1.47) mm and at the apical level 0.19 (1.28) and 0.21 (1.42) mm, respectively. CONCLUSIONS: The use of a guide is important for the stabilization of the drills; the greatest challenge is to control the apical position of the implants, especially in highly reabsorbed edges. The experimental sensor can become an auxiliary tool to the stereolithographic guides; however, several difficulties must still be overcome to recommend the use of a sensor.

Three-dimensional printing of occlusal devices for temporomandibular disorders by using a free CAD software program: A technical report.

Digital workflow is an important tool in the development of intraoral appliances by additive manufacturing. The purpose of this article is to present a completely digital workflow that uses a free software program and a low-cost 3D printer to fabricate occlusal devices for managing temporomandibular dysfunction. Three-dimensional images were acquired of an open maxillomandibular relationship record by using a scanner. A free software program was used to design the devices, and a 3D printer was used to produce the appliances by using a biocompatible resin. An evaluation of the technique on 5 patients showed good internal fit of the 3D-printed device with a similar need for occlusal adjustment as conventionally fabricated occlusal devices.

Accuracy of digital technologies for the scanning of facial, skeletal, and intraoral tissues: A systematic review.

STATEMENT OF PROBLEM: The accuracy of the virtual images used in digital dentistry is essential to the success of oral rehabilitation. PURPOSE: The purpose of this systematic review was to estimate the mean accuracy of digital technologies used to scan facial, skeletal, and intraoral tissues. MATERIAL AND METHODS: A search strategy was applied in 4 databases and in the non-peer-reviewed literature from April through June 2017 and was updated in July 2017. Studies evaluating the dimensional accuracy of 3-dimensional images acquired by the scanning of hard and soft tissues were included. RESULTS: A total of 2093 studies were identified by the search strategy, of which 183 were initially screened for full-text reading and 34 were considered eligible for this review. The scanning of facial tissues showed deviation values ranging between 140 and 1330 µm, whereas the 3D reconstruction of the jaw bone ranged between 106 and 760 µm. The scanning of a dentate arch by intraoral and laboratorial scanners varied from 17 µm to 378 µm. For edentulous arches, the scanners showed a trueness ranging between 44.1 and 591 µm and between 19.32 and 112 µm for dental implant digital scanning. CONCLUSIONS: The current digital technologies are reported to be accurate for specific applications. However, the scanning of edentulous arches still represents a challenge.

Immediate versus early loading of single dental implants: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Patients prefer to be rehabilitated as soon as possible if the risk of implant failure is not increased. However, whether immediate loading of single implants is riskier than early loading is not clear. PURPOSE: This systematic review and meta-analysis investigated whether the immediate loading protocol has more clinical disadvantages than the early loading protocol for single dental implants in terms of the marginal bone loss and survival rate of single implant crowns. MATERIAL AND METHODS: Two reviewers conducted an advanced electronic database search, with no language or date restriction, in Medline/PubMed, Embase, and the Cochrane Library up to May 2016. Studies were chosen by title and abstract for screening in accordance with the following inclusion criteria: dental implants studies; cohort studies (prospective and retrospective) and randomized controlled trials; samples involving partially edentulous patients; immediate loading implants; early loading implants; and n≥10 participants. RESULTS: Of the 5710 studies initially identified, 5 fulfilled the inclusion criteria. A meta-analysis yielding risk differences (RD) and mean differences (MD) with a 95% confidence interval (CI) was performed. The trials included showed no significant differences between early and immediate loading protocols in single implant crowns with regard to survival rate at 1 and 3 years (RD, -0.00; 95% CI, -0.04 to 0.04; P=.990 for 1 year and P=.980 for 3 years) or marginal bone loss at 1 year (MD, 0.09; 95% CI, -0.02 to 0.19; P=.110) and 3 years (MD, -0.23; 95% CI, -0.47 to 0.01; P=.060). CONCLUSIONS: This systematic review showed no significant differences between early and immediate loading protocols in single implant crowns with regard to survival rate or marginal bone loss at 1 or 3 years.

Photoelastic analysis of stress distribution in mandibular second molar roots caused by several uprighting mechanics.

INTRODUCTION: Mandibular molar uprighting is indicated when mesial inclination of the second molars occurs because of missing first molars. There are many methodologies to perform such movement. In this study, we aimed to analyze and compare the stress distributions in different molar uprighting techniques. METHODS: Four photoelastic models were designed to evaluate different mandibular second molar uprighting techniques: a miniscrew positioned in the retromolar region, a beta-titanium alloy cantilever spring, a beta-titanium alloy wire with a T-loop spring, and an 0.018-in stainless steel archwire with an open-coil spring between the second premolar and the second molar. RESULTS: On the miniscrew test specimen, the greatest concentration of strains was observed in the cervical zone of the distal root. The cantilever spring had many strains in the cervical zone of the mesial root. On the T-loop spring test specimen, mainly the observed strains were in the apical zone of the mesial root. The open-coil spring specimen showed fringes in the cervical zone and the apical zone of the mesial root without formation of large sequences of strains. CONCLUSIONS: The miniscrew mechanical action had the least and the cantilever spring mechanical action had the greatest strain means on the roots of mandibular second molars.

Influence of Abutment Surface Treatments on Screw Loosening of Morse Taper Implants.

PURPOSE: To evaluate the effect of blasting and bonding on abutment surface to prevent screw loosening in Morse taper connections. MATERIAL AND METHODS: Twenty-eight Morse taper connection implants were divided into 4 groups: no treatment (G1), blasting (G2), bonding (G3), and blasting + bonding (G4). In groups G2 and G4, the abutments were blasted with aluminum oxide granules; in groups G3 and G4, the conical abutment region was covered with a thin layer of bond thread lock agent. In all implants, the abutment-implant joint was tightened at a torque of 35 Ncm. The specimens were submitted to the mechanical cycling, under an oblique load for 1.0 × 10 cycles. The torque was measured with a digital torque meter. Data were analyzed by the t test, one-way analysis of variance, and Tukey tests (95%). RESULTS: The loosening strength was significantly higher in group G4 (35.83 ± 3.02 Ncm). There was no significant difference among groups G1 (25.86 ± 1.96 Ncm), G2 (25.86 ± 3.29 Ncm), and G3 (26.14 ± 2.12 Ncm). CONCLUSION: The association of blasting and bonding on abutment surface can be used to prevent screw loosening in Morse taper implants.

Computer-aided analysis of digital dental impressions obtained from intraoral and extraoral scanners.

STATEMENT OF PROBLEM: The internal and marginal adaptation of a computer-aided design and computer-aided manufacturing (CAD-CAM) prosthesis relies on the quality of the 3-dimensional image. The quality of imaging systems requires evaluation. PURPOSE: The purpose of this in vitro study was to evaluate and compare the trueness of intraoral and extraoral scanners in scanning prepared teeth. MATERIAL AND METHODS: Ten acrylic resin teeth to be used as a reference dataset were prepared according to standard guidelines and scanned with an industrial computed tomography system. Data were acquired with 4 scanner devices (n=10): the Trios intraoral scanner (TIS), the D250 extraoral scanner (DES), the Cerec Bluecam intraoral scanner (CBIS), and the Cerec InEosX5 extraoral scanner (CIES). For intraoral scanners, each tooth was digitized individually. Extraoral scanning was obtained from dental casts of each prepared tooth. The discrepancy between each scan and its respective reference model was obtained by deviation analysis (µm) and volume/area difference (µm). Statistical analysis was performed using linear models for repeated measurement factors test and 1-way ANOVA (α=.05). RESULTS: No significant differences in deviation values were found among scanners. For CBIS and CIES, the deviation was significantly higher (P<.05) for occlusal and cervical surfaces. With regard to volume differences, no statistically significant differences were found (TIS=340 ±230 µm; DES=380 ±360 µm; CBIS=780 ±770 µm; CIES=340 ±300 µm). CONCLUSIONS: Intraoral and extraoral scanners showed similar trueness in scanning prepared teeth. Higher discrepancies are expected to occur in the cervical region and on the occlusal surface.

Assessment of Marginal Bone Loss around Platform-Matched and Platform-Switched Implants - A Prospective Study.

The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p<0.05) and (0.99 mm vs 0.82 mm, p<0.05), respectively. Additionally, bone loss area (BLa) was greater (0.77 mm2 vs 0.63 mm2; p<0.05) for platform-matched compared to platform-switched abutments. Platform-switching has a positive impact upon the amount of bone modeling after loading implants with internal hexagon connection.

Assessment of Marginal Bone Loss around Platform-Matched and Platform-Switched Implants - A Prospective Study

Abstract The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p<0.05) and (0.99 mm vs 0.82 mm, p<0.05), respectively. Additionally, bone loss area (BLa) was greater (0.77 mm2 vs 0.63 mm2; p<0.05) for platform-matched compared to platform-switched abutments. Platform-switching has a positive impact upon the amount of bone modeling after loading implants with internal hexagon connection.

Resumo O objetivo do presente estudo foi realizar uma avaliação radiográfica assistida por computador do efeito da plataforma reduzida sobre a perda óssea marginal (MBL) ao redor de implantes. Quarenta pacientes que necessitavam um implante em mandíbulas parcialmente edêntulas não enxertadas foram selecionados e divididos em implantes que receberam pilares de plataforma igualada (grupo controle) ou implantes com pilares de plataforma reduzida (grupo teste). Radiografias periapicais digitais padronizadas foram realizadas no momento da instalação do implante (T0), carregamento do implante (T1) e 1 ano após carregamento funcional (T2). Avaliação radiográfica assistida por computador da MBL horizontal, vertical e mudanças de área foi realizada e comparada entre os intervalos de tempo (T1-T0, T2-T1 e T2-T0). A média radiográfica da MBL horizontal (hMBL) e da MBL vertical (vMBL) do momento da instalação do implante até 1 ano após carregamento (T2-T0) foram significativamente aumentadas ao redor dos pilares de plataforma igualada quando comparado com os pilares de plataforma reduzida (1,04 mm vs 0,84 mm, p<0,05) e (0,99 mm vs 0,82,mm, p<0,05), respectivamente. Além disso, a área de perda óssea (BLa) foi maior (0,77 mm2 vs 0,63 mm2; p<0,05) para plataforma igualada comparada com pilares de plataforma reduzida. Plataforma reduzida tem um impacto positivo na remodelação óssea após carregamento de implantes com conexão interna hexagonal.

CEREC Chairside System to Register and Design the Occlusion in Restorative Dentistry: A Systematic Literature Review.

OBJECTIVE: The aim of this review was to update the literature with regard to the digital methods available by CEREC Chairside system to register and design the occlusion, to report their efficacy and technical innovations in the field of Restorative Dentistry. A search strategy was performed using the key-words: "virtual articulator," or "CAD-CAM and occlusal recording," or "CAD-CAM and occlusion register," or "CAD-CAM and occlusal contacts," or "CAD-CAM and prosthesis." MATERIAL AND METHODS: Inclusion criteria comprised studies evaluating the use of digital methods available by CEREC System for occlusal registration and design during prosthodontics treatment. PubMed and Cochrane library and reference lists were searched up to January 2016. RESULTS: The search resulted in 280 articles after removing duplicates. Subsequently, 233 records were excluded and 49 studies were selected for reading in full. Eleven articles were considered eligible for the systematic review (4 in vitro and 7 clinical studies). CONCLUSION: Scientific evidence suggests that digital methods were accurate to register and design the occlusion of dental prostheses. Nevertheless, further clinical studies are required to establish a conclusion with regard to its accuracy in prosthodontics treatment. CLINICAL SIGNIFICANCE: Digital technologies allow the design of occlusal surfaces of CAD-CAM fabricated prostheses using innovative approaches. This systematic review aimed to update the literature to help dentists determine the most appropriate digital method to register and design the occlusal surface of CAD-CAM crowns. (J Esthet Restor Dent 28:208-220, 2016).

Incisal coverage or not in ceramic laminate veneers: A systematic review and meta-analysis.

BACKGROUND: There is no consensus on whether incisal coverage is a risk or a protective factor in preparations for ceramic veneers. OBJECTIVE: The aim of this systematic review and meta-analysis was to evaluate the survival rates of preparation designs for ceramic veneers with and without incisal coverage. METHODS: Primary clinical studies with the following characteristics were included: 1) studies related to ceramic laminate veneers and 2) prospective or retrospective studies conducted in humans. From the selected studies, the survival rates and failures rates for ceramic veneers were extracted according to preparation design, with or without incisal coverage. The Cochran Q test and the I(2) statistic were used to evaluate heterogeneity. Metaregression, meta-analysis were performed. Two reviewers searched in the MEDLINE (Pubmed) and Cochrane Central Register of Controlled Trials (Central) electronic databases, from 1977 to June 5, 2016, without language restrictions. RESULTS: Eight studies out of 1145 articles initially identified were included for risk of bias and systematic assessment. No study was identified for crystalline ceramic veneers. The estimated survival rate for laminate veneers with incisal coverage was 88% and 91% for those without incisal coverage. Incisal coverage presented an OR of 1.25. CONCLUSIONS: Irrespective of the preparation designs, with or without incisal coverage, ceramic veneers showed high survival rates. As regard implications for future clinical research studies, randomized clinical studies are necessary to compare preparation designs with and without incisal coverage, and to provide clear descriptions of these preparation designs.

Restoration of the Occlusal Vertical Dimension with an Overlay Removable Partial Denture: A Clinical Report.

The process of tooth loss throughout life associated with severe occlusal wear may pose a challenge in the rehabilitation of partially edentulous arches. In these cases, many therapeutic procedures are necessary because each tooth must be restored to obtain the correct anatomical contour and recover the occlusal vertical dimension (OVD). A removable partial denture (RPD) with occlusal/incisal coverage, also known as an overlay RPD, is an alternative treatment option with fewer interventions, and, consequently, lower cost. This clinical report reviews the principles involved in the clinical indication for an overlay RPD, as well as the necessary planning and execution, to discuss the feasibility and clinical effectiveness of this treatment, identifying the indications, advantages, and disadvantages of this procedure through the presentation of a clinical case. The overlay RPD can be an alternative treatment for special situations involving partially edentulous arches in patients who need reestablishment of the OVD and/or realignment of the occlusal plane, and it can be used as a temporary or definitive treatment. The main advantages of this type of treatment are its simplicity, reversibility, and relatively low cost; however, further studies are needed to ensure the efficacy of this treatment option.

Influence of implant-retained silicone oculo-palpebral prosthesis on stress distribution: a pilot study using a photoelastic model.

PURPOSE: The purpose of this pilot study was to evaluate the behavior of stresses surrounding orbital model implants subjected to a load of a silicone oculo-palpebral prosthesis. MATERIALS AND METHODS: A photoelastic model was constructed mimicking the orbital cavity of an adult patient who underwent left orbital resection. Two 3.75 × 5-mm extraoral implants with 3.75 × 5.25-mm magnetic connectors were placed in the model to anchor a silicone oculo-palpebral prosthesis. The stress generated by prosthesis retention was evaluated using photoelasticity at 15, 30, and 60 minutes. The polariscope images were analyzed qualitatively at five areas surrounding the implants. These same areas were analyzed quantitatively using Matlab software based on the RGB color pattern. Data were compared with the Wilcoxon test. RESULTS: Using fringe localization, the qualitative analysis demonstrated that the area between the implants had the greatest stress. The quantitative analysis showed that the peri-implant stress increased significantly in proportion to the increase in prosthesis retention time. CONCLUSION: The oculo-palpebral prosthesis generated stress around the implants, and the stress intensity was directly proportional to the duration of use.

Stress Distribution Around Dental Implants Placed at Different Depths.

INTRODUCTION: The progressive bone loss at the neck of dental implant is a clinical concern since it affects the maintenance of dental aesthetics. The current study evaluated the influence of insertion depth, prosthetic connection, and type of loading on the stress distribution around dental implants, using photoelastic evaluation. MATERIALS AND METHODS: A total of three blocks of photoelastic resin for each type of implant connection (external hexagon, external hexagon flattened, internal hexagon, and Morse taper) were built. Each block differed in the position of the implant platform in relative to the upper margin of the block: I (2 mm below), II (at the same level), and III (2 mm above). A force of 100 N was applied to both straight and tilted abutments. Totally, 4 selected points were evaluated at 1 side of the implant. Quantitative data were collected for the statistical analysis. RESULTS: A multiple linear regression showed the relation between the stress distribution and the insertion depth. For all the implant types, both with straight and tilted abutments, group I presented the lowest stress concentration around the fixture when compared with group II and III (P < 0.05). CONCLUSIONS: Within the limitations of this study, it could be concluded that the deeper the insertion, the lower the stress concentration.