Search

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.

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.

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.

medical and dental treatment in the form of ozonized water and oxygen / ozone gas mixture and associated with photobiomodulation therapy. The evidence map was based on the 3iE evidence searched in the databases: LILACS, PubMed, EMBASE and Cochrane Library, seeking systematic and narrative reviews, analyzed in an excel characterization spreadsheet. Three independent literature reviewers screened the systematic review search output blinded at the software Rayyan. The full-text publications were screened against the specified inclusion criteria by thre independent reviewers; disagreements were resolved through discussion. Forty-two studies were found, 16 of which were systematic reviews and 26 narrative reviews, published between 2006 and 2021, with different levels of confidence. The intervention that most appeared in the literature was oral ozone therapy as a bacterial colony reduction and decontamination agent, with emphasis on topical oxygen-ozone gas mixtures, topical ozonized water. Oral ozone therapy can bring benefits to clinical practice and patients. The evidence map provides an easy visualization of valuable information for patients, health practitioners and managers, in order to promote evidence-based complementary therapies. Este estudio tuvo como objetivo hacer el mapa de evidencias sobre la ozonoterapia, como abordaje integrador y / o complementario al tratamiento médico y odontológico en forma de agua ozonizada y mezcla de oxígeno / ozono gaseoso y asociado a la terapia de fotobiomodulación. El mapa de evidencia se basó en la evidencia 3iE buscada en las bases de datos: LILACS, PubMed, EMBASE y Cochrane Library, buscando revisiones sistemáticas y narrativas, analizadas en una hoja de cálculo de caracterización en Excel. Tres revisores independientes de la literatura examinaron el resultado de la búsqueda de la revisión sistemática cegados en el software Rayyan. Tres revisores independientes examinaron las publicaciones de texto completo en función de los criterios de inclusión especificados; Los desacuerdos fueron resueltos mediante una discusión. Se encontraron 42 estudios, 16 de los cuales fueron revisiones sistemáticas y 26 revisiones narrativas, publicados entre 2006 y 2021, con diferentes niveles de confianza. La intervención que más apareció en la literatura fue la ozonoterapia oral como agente reductor de colonias bacterianas y descontaminación, con énfasis en mezclas tópicas de oxígeno-ozono gaseoso, agua ozonizada tópica. La ozonoterapia oral puede aportar beneficios a la práctica clínica y a los pacientes. El mapa de evidencia proporciona una visualización fácil de información valiosa para pacientes, profesionales de la salud y administradores, con el fin de promover terapias complementarias basadas en evidencia. Este estudo teve o objetivo de realizar um mapa de evidências sobre a ozonioterapia, como abordagem integrativa e / ou complementar ao tratamento médico-odontológico na forma de água ozonizada e mistura de oxigênio / gás ozônio e associada à fotobiomodulação. O mapa de evidências baseou-se nas evidências 3iE pesquisadas nas bases de dados: LILACS, PubMed, EMBASE e Biblioteca Cochrane, buscando revisões sistemáticas e narrativas, analisadas em planilha de caracterização excel. Três revisores independentes da literatura examinaram o resultado da pesquisa da revisão sistemática cegos para o software Rayyan. As publicações de texto completo foram selecionadas de acordo com os critérios de inclusão especificados por três revisores independentes; desacordos foram resolvidos por meio de discussão. Foram encontrados 42 estudos, sendo 16 revisões sistemáticas e 26 revisões narrativas, publicadas entre 2006 e 2021, com diferentes níveis de confiança. A intervenção que mais apareceu na literatura foi a terapia de ozônio oral como agente de redução e descontaminação de colônias bacterianas, com ênfase em misturas tópicas de oxigênio-ozônio e água ozonizada tópica. Conclusão: A ozonioterapia oral pode trazer benefícios à prática clínica e aos pacientes. O mapa de evidências fornece uma visualização fácil de informações valiosas para pacientes, profissionais de saúde e gestores, a fim de promover terapias complementares baseadas em evidências.

The aim of this study was to investigate the effects of the use of an occlusal splint on postural balance considering the occlusal splint as a device for treating temporomandibular joint disorder. A randomized, controlled, prospective clinical trial was conducted. The research group consisted of 49 patients (36 as test group and 13 as control group) between 18 and 75 years old, both genders, diagnosed as temporomandibular disorder by Research Diagnostic Criteria/Temporomandibular Disorders questionnaire and magnetic resonance imaging of the temporomandibular joints. Test group was treated with orientations for physiotherapeutic exercises and occlusal splint, whereas control group received orientation for physiotherapeutic exercises only. Postural equilibrium was evaluated by means of a force plate. After 12 weeks, the groups were re‐evaluated. Patients from both groups presented a significant increase in antero‐posterior speed with eyes closed, test group (P

To evaluate the effect of blasting and bonding on abutment surface to prevent screw loosening in Morse taper connections.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%).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).The association of blasting and bonding on abutment surface can be used to prevent screw loosening in Morse taper implants.

Objectives: The aim of this study is to compare the mechanical characteristics of resins for 3D printers with the acrylic resins that have been used in Dentistry, according to the post-processing method. Materials and Methods: Using an SLA 3D printer (Form 2 – Formlabs, Massachusetts, USA), samples (discs) were produced with the printer’s resins, Dental SG®, Dental LT®, Clear®, and Grey®. Samples made of thermopolimerized and auto polymerized acrylic resins were produced as well (Gold Standart parameters). The Knoop Hardness (KH) tests were performed using microdurometer HMV-2 (Shimadzu, Kyoto, Japan). Results: The results showed the Dental SG resin presented the highest KH, compared with thermopolimerized acrylic resin, the Clear and Dental LT resins KH were compared with auto polymerized acrylic resin, and the non-post cured Grey resin (not for intraoral use), as well as the Dental LT resin, showed the lowest KH. Conclusions: Considering the hardness, the printer’s resins are comparable with the acrylic resins established, when the post-processing method is thoroughly followed. The absence of material’s post-processing reduce significantly the material’s hardness. Clinical relevance: Regarding the use of 3D printing in Dentistry, the development of materials adequate for the equipment, biocompatible for intraoral uses, and compatible mechanical proprieties are essential. Objetivos: O objetivo deste estudo é comparar as características mecânicas das resinas para impressoras 3D com as resinas acrílicas utilizadas em Odontologia, de acordo com o método de pós-processamento. Materiais e Métodos: Utilizando uma impressora SLA 3D (Form2 – Formlabs, Massachusetts, EUA), amostras (discos) foram produzidas com as resinas da impressora, Dental SG®, Dental LT®, Clear® e Grey®. Também foram produzidas amostras feitas de resinas acrílicas termopolimerizadas e autopolimerizadas (parâmetros Gold Standart). Os testes de dureza Knoop (KH) foram realizados usando o microdurômetro HMV-2 (Shimadzu, Kyoto, Japão). Resultados: Os resultados mostraram que a resina Dental SG apresentou o KH mais alto, em comparação com a resina acrílica termopolimerizada, as resinas Clear e Dental LT KH foram comparadas com a resina acrílica autopolimerizada e a resina Grey sem pós-cura (não para uso intraoral), assim como a resina Dental LT, apresentou o menor KH. Conclusões: Considerando a dureza, as resinas da impressora são comparáveis às resinas acrílicas, quando o método de pós-processamento é completamente seguido. A ausência do pós-processamento do material reduz significativamente a dureza do material. Relevância clínica: No que diz respeito ao uso da impressão 3D em Odontologia, o desenvolvimento de materiais adequados ao equipamento, biocompatíveis para usos intraorais e propriedades mecânicas compatíveis é essencial.

Objetivo: revisar sistemáticamente en la literatura tasa de supervivencia de los implantes de circonio y aleación de titanio y circonio (Ti-Zr). Métodos: los estudios clínicos de las bases de datos Pubmed, Embase y Cochrane fueron seleccionados por tres investigadores con criterios de inclusión: implantes de aleación de circonia o Ti-Zr, con un mínimo de un año de seguimiento evaluando las tasas de supervivencia y criterios de exclusión: laboratorio, Cigomáticos y pacientes con enfermedades sistémicas. El acuerdo entre los examinadores se evaluó mediante la prueba estadística Kappa. Realizamos un análisis de heterogeneidad i2, un modelo de efectos aleatorios y fijos que utiliza las tasas de supervivencia de ambos tipos de implantes y el análisis del riesgo de sesgo (bias). Resultados: se encontraron 1755 artículos de la búsqueda inicial y se incluyeron 23 estudios. El acuerdo entre examinadores de la prueba kappa fue del 72%. La tasa de supervivencia de la aleación de titanio y la aleación de circonia fue del 97% y del 90.3% para los implantes de circonio. En ambos tipos de modelos, la tasa de supervivencia del tipo de implante TiZr fue ligeramente superior a la de los otros tipos de implantes y el intervalo de confianza del 95%. El análisis del riesgo de sesgo mostró bajo riesgo. Conclusión: Los datos obtenidos en este estudio muestran que los implantes de aleación TiZr e Zr presentaron altas tasas de supervivencia, aún así, se necesitan estudios clínicos con un seguimiento más prolongado para respaldar el uso de los implantes Zr.

O objetivo desta pesquisa foi avaliar as áreas de tensões produzidas por arcos ortodônticos expandidos associados a diferentes tipos de bráquetes durante a fase de alinhamento e nivelamento ortodôntico. A partir de modelos de gesso adquiridos durante a fase de nivelamento ortodôntico do arco dentário inferior de um mesmo paciente, obteve-se 3 modelos fotoelásticos que receberam 3 diferentes tipos de bráquetes: convencional (Ovation®, GAC International, New York, EUA), autoligável ativo (In-Ovation®, GAC International, New York, EUA) e autoligável passivo (Damom 3MX®, Ormco, Califórnia, EUA), associados a arcos de liga de níquel-titânio 0.014\" e 0.014\" x 0.025\" e de liga de aço 0.019\" x 0.025\". Os modelos fotoelásticos com os respectivos arcos e bráquetes ortodônticos foram observados em polariscópio circular, e as imagens fotográficas das regiões dos incisivos, pré-molares e molares foram analisadas qualitativa e quantitativamente. A análise qualitativa foi realizada pela identificação da ordem e coloração das franjas nos locais onde ocorreram, e a quantitativa foi realizada utilizando o software Matlab® para a identificação dos padrões de cores RGB nas áreas dos terços médio-apicais dos dentes de cada região. Os dados obtidos das diferentes associações arcos/bráquetes ortodônticos foram comparados estatisticamente pelo teste de Wilcoxon. Pode-se concluir que, na região dos incisivos, as maiores tensões ocorreram quando os arcos ortodônticos foram associados aos bráquetes autoligados passivos. Na região dos pré-molares, as maiores tensões ocorreram quando o arco 0.014\" foi associado ao bráquete convencional, em movimentos de segunda ordem (extrusão) e de angulação, e quando os arcos retangulares foram associados aos bráquetes autoligados passivos. Na região dos molares, as maiores tensões ocorreram quando os arcos retangulares foram associados aos tubos ortodônticos com maior prescrição de inclinação (Ovation® e In-Ovation®). The aim of this research was to evaluate the areas of tension produced by expanded orthodontic arches associated with different types of brackets during the orthodontic leveling phase. From plaster models of a single patient lower dental arch obtained during the orthodontic alignment and leveling phase, three photoelastic models were developed that received three different types of brackets: convencional (Ovation®, GAC International, New York, EUA); active self ligation bracktes (In-Ovation®, GAC International, New York, EUA) e passive self ligation bracktes (Damom 3MX®, Ormco, Califórnia, EUA), associated with 0.014\" and 0.014\" ? 0.025\" titanium-nickel alloy arches and 0.019\" ? 0.025\" alloy steel arches. These models were analyzed in a circular polariscope; photographic images of the incisor, premolar, and molar regions were qualitatively and quantitatively analyzed. The first analysis was obtained by identifying the photoelastic fringe order at sites where they occurred, and the second one was obtained using Matlab® software to identify RGB color patterns in middle apical tooth areas of each region. Data from the different orthodontic arches and brackets were compared using the Wilcoxon test. Our results showed that in the incisors region the greatest tensions occurred when the orthodontic arches were associated to the self-ligating passive brackets; in the premolars region, by the association of the 0.014\" arch and conventional bracket in second order (extrusion) and angulation movements and when the rectangular arches were associated with the passive self-ligating brackets. The greatest tensions in the molar regions occurred by association of rectangular arches and inclination high prescriptions orthodontics tubes (Ovation® and In-Ovation®).

The aim of this study was to review potential deviation factors in stereolithographic surgical guides for dental implantology, warnings, and limitations of the system.An electronic search in databases EMBASE, the Cochrane Library, and PubMed were conducted by 3 researchers to collect information on the accuracy of static computer-guided implant placement to summarize and analyze the overall accuracy. The latter included a search for correlations between factors such as support (teeth/mucosa/bone), number of templates, use of fixation pins, jaw, template production, guiding system, and guided implant placement in articles related to guided surgery with stereolithographic static systems. Studies published between 2012 and 2017 were reviewed.From 761 identified articles, a total of 24 articles were reviewed, which included 2767 dental implants. Data from studies analysis had shown a mean deviation of 3.08 degrees in angular position, 1.14 at the entry point, and 1.46 at apex position. Involved deviation factors were related to planning, laboratory, and surgical phases.Guided surgery may have a limited precision as technique, which surgeons need to be aware in the planning process. This review suggests some security measures in guided surgery process.

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)

Compreender a importância de estrategias de impressao 3D e uma chave para obter aparelhos dentarios estaveis, aperfeicoados e consistentes utilizando tecnologias digitais. Este estudo tem como objetivo apresentar a influencia da inclinacao da impressao sobre a precisao do ajuste intraoral de placas de arco de cobertura total. As placas foram projetadas para dois pacientes com uso do software CAD e de uma impressora 3D SLA com diferentes inclinacoes (0, 30 e 90 graus), e o ajuste interno foi verificado na boca dos pacientes. Foi possivel verificar diferencas entre o ajuste interno das placas, com os piores resultados para placas com inclinacao de 90 graus, em­bora estudos mais detalhados sejam recomendados. DESCRITORES | Impressao tridimensional; Precisao; Medicao das dimensoes; Placa oclusal; Inclinacao da Impressao.

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.

Statement of problem Analysis of the wear coefficient (k) of the superficial and deep layers of acrylic resin teeth can help predict denture durability, but little has been published on the wear coefficient of denture teeth. Purpose The purpose of this in vitro study was to determine the k value for the superficial and deep layers of the acrylic resin teeth of 6 different brands by using the fixed-ball microabrasive wear method. Material and methods Six artificial tooth specimens of 4 commercial brands were tested: Artiplus IPN (Ar), Biotone IPN (Bi), Magister (Ma), Premium (Pr), Trilux (Tr), and SR Vivodent (Vi). Two specimens from each brand were created, one for the superficial layer and the other for the deep layer. The test was performed on fixed-ball microabrasive wear equipment set to operate at a constant normal force of 0.5 N and a rotation speed of 100 rpm. The test time periods were 5.00, 8.33, and 11.66 minutes. The characteristics of the wear craters were measured by using an optical microscope at a magnification of ×50 and Leica Microsystems software. Wear coefficient (k) values were deduced by using the Archard equation for abrasive wear, Q=k·N, and were analyzed by using 1-way analysis of variance, complemented by the Tukey HSD test (α=.05). A different analysis was used for each layer. Results The analysis of variance of the wear coefficient revealed significant differences among the groups regarding the superficial layers (P=.009). The Tukey HSD test showed that the k values for the superficial layers of Artiplus specimens were significantly lower than those of the Vivodent and Magister specimens. Conclusions One brand (Ar) presented significantly lower wear coefficient value for the surface layer. No difference in wear coefficient values was found among the tooth brands for the deep layer.

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.

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.

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.

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.The purpose of this in vitro study was to evaluate and compare the trueness of intraoral and extraoral scanners in scanning prepared teeth.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).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).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.

Statement of problem Limited evidence is available comparing digital versus conventional impressions from the point of view of patient preference. Purpose The purpose of this systematic review was to identify and summarize the available literature related to patient-centered outcomes for digital versus conventional impression techniques. Material and methods The databases Medline, Cochrane, Science Direct, Scopus, and Embase were electronically searched and complemented by hand searches. All published papers available on the databases from 1955 to July 2016 were considered for title and abstract analysis. Results A total of 2943 articles were initially identified through database searches, of which only 5 met the inclusion criteria for qualitative analysis. Four studies comparing patient-reported outcome measures (PROMs) between conventional and digital impressions revealed that the digital technique was more comfortable and caused less anxiety and sensation of nausea. Only 1 study reported no difference between the techniques regardless of patient comfort. Two studies reported a shorter procedure for the conventional technique, whereas 3 studies reported a shorter procedure for the digital technique. Conclusions A lack of clinical studies addressing patient outcomes regarding digital prosthodontic treatments was observed among the included articles. However, current evidence suggests that patients are more likely to prefer the digital workflow than the conventional techniques.

Background Chemical modifications of the dental implant surface that improve the wettability result in a faster and better osseointegration. Purpose The aim of this randomized clinical trial was to evaluate the implant stability quotient (ISQ) of implants with similar designs, treated with 2 surfaces, sandblasted acid-etched (SAE) and hydrophilic SAE, within the initial 16 weeks of healing. Material and methods A total of 64 implants (32 SAE—control group and 32 modified SAE—test group) with the same design, length, and diameter (conical and compressive, 4.3 × 10 mm) were inserted into the posterior maxillae of 21 patients partially edentulous. The ISQ values were collected at post-surgery (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), 5 weeks (T4), 8 weeks (T5), 12 weeks (T6), and 16 weeks (T7). Results None of the implants failed. Test group presented ISQ values higher than the control group (ANOVA—P

The aim of this in vitro study was to evaluate, using the photoelastic analysis method, the stress distribution in mandibular bone surrounding a bar-clip overdenture when 2 implant angulations were simulated. Two mandibular photoelastic models were manufactured, with 2 implants embedded in the interforaminal region: model 1 - PAPI, a photoelastic analysis model with parallel implants; and model 2 - PAAI, a photoelastic analysis model with angled implants. A bar-clip retention system and an overdenture were positioned over the implants, and loads of 1.0, 2.0 and 3.0 bars were applied. The resultant stresses that developed in the supporting structure were photoelastically monitored and were recorded photographically. The results showed that there were no similarities in the areas of stress among the photoelastic resin models when the angulation of the implants was evaluated. Model 1 - PAPI presented a higher stress concentration at the implant apex, while in model 2 - PAAI, there were higher stress concentrations on the mesial and distal implant faces. Within the limitations of this study, it was concluded that the PAPI photoelastic model demonstrated better stress transfer compared to the PAAI model, since the forces oriented along the axis were better absorbed by the bone.

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

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."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.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).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.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).

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.

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.

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.

New synthetic polymeric membranes of lactic acid were prepared with different chemical composition through copolymerization with e-caprolactone and ethylene oxide segments. The prepared copolymers were characterized by hydrogen and carbon-13 nuclear magnetic resonance (1H-NMR and 13C-NMR) and presented wide range of mechanical properties demonstrated by dynamic mechanical thermal analysis (DMA). Porous membranes were prepared by dissolving the polymer in the presence of salts (NaCl or hydroxyapatite) and/or lower mass poly(ethylene glycol) (Mn = 600 or 1,000 g · mol−1). The membranes presented new mechanical and biological characteristics and were suitable for cell penetration, anchorage, differentiation and proliferation. Adherence of cultured fibroblasts on membranes indicates biocompatibility.

Diante da importância das próteses parciais fixas, próteses parciais removíveis e próteses híbridas, o principal objetivo deste trabalho é realizar uma revisão da literatura a respeito dos preparos dentais com finalidade protética. O preparo dental para uma prótese é um dos fatores críticos, que deve ser cuidadosamente planejado e executado para permitir a longevidade do tratamento. Esse deve restabelecer função, mastigatória e fonética, além de estética, requisitos estes fundamentais para a satisfação do paciente perante os resultados finais de uma reabilitação. Em PPF a quantidade de desgaste das paredes dentais preparadas, angulação e localização do término cervical influenciam muito a longevidade e a estética da restauração final. O preparo dental, nesse tipo de prótese, deve permitir uma espessura adequada de material restaurador, ao mesmo tempo em que deve preservar a integridade pulpar e periodontal. Já nas PPRs o preparo de adequados planos-guias, descansos para apoios oclusais e contornos dentais se tornam extremamente necessários para o sucesso da reabilitação por meio desse tipo de prótese, que tem como objetivo a preservação da saúde bucal, conforto e função para o paciente. Já a redução da altura dos remanescentes radiculares em próteses híbridas é importante, pois diminui possíveis riscos de mobilidade e consequente perda do elemento, visto que a preservação dessas raízes previne perda óssea, promovendo melhora na retenção e estabilidade da prótese. Pelos trabalhos da literatura aqui revisados, pode-se concluir que, os preparos dentais são fatores primordiais no sucesso da reabilitação protética.

A osseointegração é, sem sombra de dúvida, a responsável pelo notável avanço tecnológico, mudança de conceitos filosóficos e condução de planejamentos voltados à reabilitação oral, como também, pela disseminação e propagação dos conhecimentos, interferindo sobremaneira nas demais áreas da Odontologia contemporânea. Os implantes osseointegrados são cada vez mais utilizados para substituir dentes perdidos em várias situações, desde a perda de um único dente até em casos de completo edentulismo. A reabilitação de pacientes desdentados com próteses fixas ou overdentures removíveis é um processo complexo e desafiador. Existem fatores cruciais para a decisão de uma prótese fixa ou removível para se obter estética, fonética, promover conforto e função. Além disso, o resultado do tratamento está relacionado à taxa de sobrevivência dos implantes, à manutenção do osso marginal, à saúde do tecido periimplantar, à longevidade dos componentes protéticos e da prótese em si. Esse estudo buscou analisar as vantagens e desvantagens das reabilitações protéticas sobre implantes, fixas e removíveis, para pacientes totalmente desdentados.

Introdução: Devido à preocupação com a influência da topografia da resina na retenção mecânica de microrganismos na superfície da prótese, este trabalho se propõe analisar e discutir o desempenho de quatro marcas comerciais de resinas resilientes para uso clínico, quanto à lisura superficial e sua exotermia. Métodos: Foram preparadas 80 amostras de 4 marcas comerciais, sendo 20 amostras de cada grupo: Grupo A (resina Coe-Soft), Grupo B (resina Dentusoft), Grupo C (resina Soft Confort Dencril) e Grupo D (resina Trusoft). As amostras foram observadas em microscópio ótico com relação ao seu aspecto superficial exotermia da reação de polimeriza- ção foi aferida por termômetro de radiação infravermelha. Resultados e Conclusões: Observadores concluíram que o Grupo C apresentou um aspecto superficial mais regular e uniforme e que todos os grupos são seguros em mucosa oral por não apresentarem exotermia significativa.

The digital smile design is a practical diagnosis method that can assist the clinician to visualize and measure dentogingival discrepancies. This clinical report aims to present the associated steps, from the diagnosis of the alterations diagnosis through to the final aesthetic result. A 37-years-old female patient presented as her main complaint the tooth form and colour discrepancies. Applying the digital smile design principle, the necessary measures for a harmonic smile correction could be accurately determined. The initial diagnosis led to a wax up of the master cast that was duplicated in acrylic resin directly in the mouth. This temporary restoration guided the periodontal surgery and the final pressed ceramic crown restoration. We conclude that the digital smile design concept seems to be a useful tool to achieve a satisfactory aesthetic result.

Scientific development and increasing technological progress in the field ofdentistry have allowed the use of many resources in theoral rehabilitationplanning. In complex cases, in order to achieve projected final results,many procedures should be undertakenpriorto implant surgery. Prosthetic rehabilitation planningand bone graft procedures canbetter restorethe functional, aesthetic, social and emotional needs of the patient. This clinical case report shows the oral conditions of a woman who underwent several surgical proceduresfor maxillary reconstruction with autogenous bone grafts from the iliac crest. In this case, a bone volume guide was made to evaluate the bone volume requirement for correct labial support for metalloceramic fixed prosthesis. After graft integration, dental implantsurgery was performed. After the osseointegration period, the prostheses was fabricated and installed on the implants, thus concluding the oral rehabilitation. In conclusion, the bone guide was a fundamental tool for final aesthetic outcome predictability.

The aim of study was to assess the stress around 10/13/15-mm implants in the mandibular area with a 15-mm cantilevered acrylic-resin–coated prostheses following the application force, using the photoelasticity method. Three photoelastic mandibular models were created containing 10-, 13-, and 15-mm implants in length and 3.75 mm in diameter. The implants had bore internal hex connections and were placed parallel to the intermental region. Abutments with 1-mm high cuffs were placed over the implants, and a single cobalt/chrome metallic prosthesis with a 15-mm cantilever, coated with thermoplastic acrylic resin, was placed on top. Loads of 1.0 and 3.0 bars were applied, and the images were photographed and assessed by photoelasticity method. The greatest stress levels were observed for the 10-mm implants. The stress pattern was the same regardless of implant length; only the magnitude of the stress along the implant body revealed changes. Increased implant length played a role in reducing stress on the investigated area of the model, and the 15-mm implants exhibited the best performance in regard to stress distribution. The highest stress levels were found in the implants closest to the cantilever and the central implant. The longest implants were more favorable in regard to the stress distribution on the peri-implant support structures in the 15-mm cantilevered prosthesis under loads.

Purpose. This study evaluated the level of tissue removal that takes place on enamel and dentin during cingulum rest seat preparation. Material and methods. A quantitative evaluation of the thickness of the remaining enamel of cingulum seat preparations to receive removable partial denture rests was carried out in 20 maxillary canines with a light optical microscope. Results. Thirty percent of the preparations were overextended into dentinal tissue, and 85% had depths that were insufficient to receive rests. (J Prosthet Dent 1998;80:319-22.)

The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface with scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and another of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the original component of the same brand as the implant was positioned, interchangeability was considered valid. Data were compared with the Kruskal-Wallis test at 5% significance level. Some degree of misfit was observed in all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6-16.9 µm, with a 4.6 µm median; and the former from 0.3-12.9 µm, with a 3.4 µm median. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for SIN and Neodent (p

Made available in DSpace on 2019-09-12T16:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011 OBJETIVO: o presente estudo analisou a distribuição de tensões, em modelo fotoelástico, gerada por arco base de intrusão de incisivos inferiores. Compararam-se as tensões entre os terços radiculares de cada incisivo e, ainda, verificou-se a existência de diferenças de concentrações de tensões entre incisivos. MÉTODOS: foram confeccionados 15 arcos base de intrusão e a força de ativação foi mensurada em 50gf na região da linha média. O modelo fotoelástico foi observado em polariscópio circular, na configuração de campo escuro, e fotografado. As fotografias frontais foram analisadas e as ordens de franjas em cada região registradas. A análise de Kappa ponderado identificou a repetibilidade do método. A comparação entre as tensões foi realizada pelo teste de Kruskal-Wallis complementado com teste de Dunn com nível alfa de 5%. RESULTADOS E CONCLUSÕES: os resultados identificaram que as maiores magnitudes de tensões foram observadas nas regiões cervicais. Ao se comparar as ordens de franjas entre os dentes, as maiores magnitudes de tensões foram observadas nos incisivos centrais. Portanto, a região cervical pode estar mais sujeita a reabsorções, assim como os incisivos centrais, por concentrarem maiores tensões. OBJECTIVE: The present study is concerned with stress distribution in a photoelastic model, caused by lower incisor intrusion using utility arch. The stress levels on the radicular thirds of each lower incisors were compared and the stress concentration differences on each incisor were evaluated. METHODS: Fifteen intrusion utility arches were made up. The activation force of 50 gf was measured in the midline. The photoelastic model was observed using a circular polariscope in a dark field configuration, and, then, photographed. Frontal photographs were analyzed, and the fringe order in each region was registered. The method replicability was assessed by the Kappa weighted analysis. The comparison between the stress levels was carried out using Kruskall-Wallis test followed by the Dunn test at p

Purpose: The objective of this work was to compare by photoelastic analysis the stress distribution along a fixed framework placed over angled or parallel implants with different gap values between the framework and one of the implants. Materials and Methods: Two photoelastic models were created: (i) with parallel implants; (ii) with a 30° angled central implant. In both cases, three implants were used, and CP titanium frameworks were constructed with commercial components. A plane polariscope was used to observe the photoelastic fringes generated after initial framework assembly, and also when an axial load of 100 N was applied over the central implant. For both models, stress analysis was conducted on well-fitting frameworks and on another with a 150 μm vertical gap between the framework and the central implant. Results: The photoelastic analysis indicated that in the model with parallel implants, stress distribution followed the implant axis, and in the model with an angled implant, a higher and nonhomogeneous stress concentration was observed around the apical region of the lateral implants. The placement of an ill-fitting framework resulted in increased preload stress patterns. Conclusion: Stresses were generated after screw tightening of the frameworks, increasing when a load was applied and when a vertical gap was present. Angled implants resulted in oblique stress patterns, which were not transferred with homogeneity to the polymeric model.

This study evaluated, in vivo, the efficacy of a denture glazing material (Palaseal) in modifying plaque colonization of dentures. Ten subjects were selected and received maxillary temporary partial removable dentures, with complete acrylic palatal coverage. The right half of the fitting surface of the denture bases were glazed with Palaseal, whereas the other half was not glazed. One month after insertion, two fragments of the resin base of all dentures were removed (one from the glazed side and another from the non-glazed side). These samples were prepared and examined by scanning electron microscopy. Three months after insertion, other fragments were obtained and analyzed. Microscopic observation at 1 month revealed that, for all patients, the plaque film was thinner on the treated side in comparison to the non-treated side. However, at the 3-month evaluation, some areas of the glaze showed cracking, and both glazed and non-glazed sides were covered by a dense bacterial plaque film. In conclusion, the findings of this clinical experiment showed that glazing denture's fitting surface did not prevent bacterial colonization, but favored plaque removal while the glaze layer remained intact. After three months, glaze cracks created microretentive areas that increased plaque accumulation. Este estudo avaliou, in vivo, a eficiência de um glaze para bases protéticas (Palaseal) em modificar a colonização microbiana de próteses. Dez indivíduos foram selecionados e receberam próteses removíveis maxilares provisórias, com cobertura total do palato em acrílico. A metade direita da superfície interna das bases protéticas foi glazeada com Palaseal enquanto a outra metade ficou sem glaze. Um mês após a instalação, dois fragmentos foram removidos de todas as bases protéticas (um do lado glazeado, outro do lado não glazeado). Estas amostras foram preparadas e examinadas em microscopia eletrônica de varredura. Três meses após a instalação, outros fragmentos foram removidos e analisados. Observações microscópicas após 1 mês revelaram que, para todos os pacientes, a placa era menos espessa do lado tratado, em comparação ao lado não-tratado. Entretanto, observações aos 3 meses mostraram que áreas do glaze haviam trincado e, tanto o lado glazeado como o lado não-glazeado estavam cobertos por uma densa camada de placa bacteriana. Os achados desse estudo clínico demonstraram que o glazeamento da superfície interna da prótese não impediu a colonização bacteriana, mas favoreceu a remoção da placa enquanto a camada de glaze esteve intacta. Decorridos 3 meses, o glaze sofreu trincas, criando áreas de microretenção que aumentaram o acúmulo de placa.

The longevity of implant-supported prosthetic rehabilitation depends largely on how the masticatory forces are transferred to the implants and surrounding bone. Anatomical conditions, bone morphology and aesthetics usually dictate implant placement in less than ideal positions for prosthetic rehabilitation and sometimes it is possible to find them with different inclinations. The purpose of this paper was to compare, through photoelastic analysis, the stress distribution in a fixed prosthesis with 3 parallel implants, to the stress distribution in the same prosthesis in the existence of an angled central implant. Two photoelastic resin models were made and a polariscope was used in the visualization of isochromatic fringes formed in the models when axial loads of 2 kg, 5 kg and 10 kg were applied to a unique central point of the prosthesis. The presence of inducted tensions (preloads) was observed in the models after applying torque to the retention screws. Preloads were intensified with the incidence of occlusal forces. In the parallel implants, the force dissipation followed the long axis. The angled implant had a smaller quantity of fringes and the stresses were located mostly around the apical region of the lateral implants. A longevidade das reabilitações orais implanto-suportadas depende, em grande parte, de como as forças mastigatórias são transferidas aos implantes e ao osso que os circunda. Condições anatômicas, morfologia óssea e estética muitas vezes ditam a colocação de implantes em posições que não são ideais para a reabilitação protética, e podemos encontrá-los com diferentes inclinações. A proposta deste trabalho foi comparar, através de análise fotoelástica, a dissipação de tensões em uma prótese fixa com 3 implantes paralelos entre si com a dissipação de tensões na mesma prótese na existência do implante central angulado. Foram confeccionados dois modelos de resina fotoelástica. Utilizou-se um polariscópio para visualização das franjas isocromáticas que se formaram nos modelos fotoelásticos quando cargas axiais de 2 kg, 5 kg e 10 kg foram aplicadas em um mesmo ponto central da prótese. Verificou-se a indução de tensões (pré-tensões) nos modelos após o apertamento dos parafusos de retenção das próteses. As pré-tensões foram agravadas com a incidência de forças oclusais. Nos implantes paralelos, a dissipação de forças seguiu os longos eixos. No implante angulado houve menor quantidade de franjas, e as tensões estavam localizadas principalmente ao redor da região apical dos implantes laterais.