Effect of layering strategy and prolonged water aging on masking ability of composite resins.

STATEMENT OF PROBLEM: Layered composite resins may adequately mask discolored substrates. However, whether color changes that occur over time affect masking ability is unclear. PURPOSE: The purpose of this in vitro study was to investigate the effect of layering and water aging on the masking ability of 2 composite resins. MATERIAL AND METHODS: Disk specimens (1.5 mm-thick and shade A1) from Charisma Diamond (CD) and Filtek Z350XT (Z350) were made according to the composite resin shade combination used in the layering strategies: bilayer for CD (enamel/dentin) and for Z350 (enamel/body and enamel/dentin) and trilayer for Z350 (enamel/body/dentin) (n=5). Color measurements were obtained with a spectrophotometer over an A3.5 ceramic substrate, and the whiteness index for dentistry (WID) was calculated. The specimens were aged in water at 37 °C and evaluated at different times: 24 hours, 1 week, 1 month, 2 months, 6 months, 12 months, 18 months, and 24 months. CIEDE2000 color differences (ΔE00) and WID differences (ΔWID) were calculated and interpreted by 50:50% color and whiteness perceptibility and acceptability thresholds. Changes among strategies and aging times were analyzed using the Kruskal-Wallis test (α=.05). Contrasts were made using the Mann-Whitney U test with Bonferroni correction (α=.001). RESULTS: ΔE00 decreased from 24 hours to 2 months of aging. From 2 months onwards, ΔE00 increased for all layering strategies and times, without significant changes in lightness for CD (P>.004). Overall, for the CD restorative system, an increase in ΔWID was observed after 1 month of aging (P<.001), while for the Z350 restorative system, ΔWID decreased after aging (P<.001), except for the Z350 bilayer strategy (enamel + dentin) at 1 week and 2 months (P>.004). For all layering strategies and aging times, color differences were higher than the 50:50% perceptibility threshold for ΔE00 and, after 6 months, higher than the 50:50% acceptability threshold for ΔE00 and the 50:50% whiteness acceptability threshold. CONCLUSIONS: The ability of the tested composite resins to mask a discolored substrate was affected by the layering approach applied and by prolonged water aging.

Masking ability of resin composites: A scoping review.

OBJECTIVE: To map the existing evidence regarding the masking ability of resin composites. OVERVIEW: The literature search was conducted electronically, based on the PRISMA Extension for Scoping Reviews-online protocol at https://osf.io/m2h67/ with no language or time restrictions. Two independent reviewers conducted the screening, and a third reviewer was consulted in case of disagreement. Studies that evaluated resin composite masking ability regardless of background, application technique, thickness, or number of layers were selected. The search found 2995 potentially eligible studies. After removal of duplicates (657), irrelevant articles (2323), 15 citations met the eligibility criteria based on title and abstract, and eight studies were included based on full text analysis (seven in vitro, and one case report). Acceptable masking ability is obtained by one layer of opaque shade resin composite or by the layering technique. A black background is masked with 1.0- to 2.0 mm-thick layers of opaque shade resin composites. Masking of the C4 background is achieved with one layer of 0.5- to 1.5 mm-thick opaque shade resin composite or by the layering technique using different combinations of enamel body and dentin shades with a final thickness of 1.5 mm. CONCLUSIONS: Acceptable masking of C4 shade background is achieved with one layer of opaque shade composite at least 0.5 mm-thick or by different combinations of the layering technique, with a final thickness of 1.5 mm. Acceptable masking of the black background of the oral cavity is achieved with a resin composite of at least 1.0 mm opaque shade. CLINICAL SIGNIFICANCE: The thickness of the resin composite layer required to achieve adequate masking is variable and depends on the translucency/opacity of the tested resin composites and the background shade.

Masking ability of resin composites: Effect of the layering strategy and substrate color.

OBJECTIVE: To evaluate the effect of layering strategy and substrate color on the masking ability of resin composites. MATERIALS AND METHODS: A1-shaded specimens from Charisma Diamond and Filtek Z350XT were produced using different layering strategies. Color measurements were made by a reflectance spectrophotometer over A2, C2, A3.5, C3, C4 substrates. Color differences were calculated and interpreted by the 50%:50% perceptibility and acceptability visual thresholds. Data was analyzed by Kruskal-Wallis and Dunn post hoc test. Chi-square test was used to determine the association between masking ability, and independent variables. RESULTS: Color differences were significantly lower on A2 and C2 in comparison with C4 for the majority of the layering strategies. Acceptable matches were observed on most of the combinations over A2. Moderately unacceptable mismatches were observed in most of the combinations over C2 and A3.5. Clearly unacceptable mismatches were observed on the C3 and C4. The ΔE00 color shifts were predominantly influenced by ΔL00 for all layering strategies and substrate colors. CONCLUSION: Masking ability was affected by the layering strategy and substrate color. Acceptable masking was associated with A2 and C2, and with layering strategy composed of 0.5 mm enamel opacity and 1.0 mm dentin opacity thicknesses, using the Filtek Z350XT. CLINICAL SIGNIFICANCE: Resin composites-shade A1-applied by different layering strategies with a final thickness of 1.5 mm were able to mask mild and moderately discolored substrates. Severely discolored substrates were not masked effectively.

Masking Ability of the Combined Application of Opaquers and Resin Composite on Discolored Backgrounds.

The aim of this study was to evaluate the masking ability of a combined application of opaquers and resin composite over discolored backgrounds: A3, A3.5, C2, C3, and C4. The groups were divided according to the opaquer brand, the number of opaquer coats (one or two), and the thickness of the resin composite layer (0.5 or 1.0 mm). The color measurements were made by a reflectance spectrophotometer (SP60, EX-Rite). The color difference between the opaquer + resin composite + background and a reference background was calculated using the CIEDE2000 formula. ANOVA and Tukey's post hoc test (α=0.05) were used to analyze the ΔE00 mean values. A bivariate analysis was used to determine the association between dependent and independent variables. The masking ability was rated by the ΔE00 visual thresholds of acceptability and perceptibility (Excellent Match: ΔE00 ≤ 0.8; Acceptable Match: 0.8 < ΔE00 ≤1.8; Moderately Unacceptable Mismatch: 1.8 < ΔE00 ≤ 3.6; Clearly Unacceptable Mismatch: 3.6 < ΔE00 ≤ 5.4; Extremely Unacceptable Mismatch: ΔE00 > 5.4). The mean ΔE00 values ranged from 0.5 to 5.52. Masking ability was affected by the opaquer brand, thickness of the resin composite layer, and background shades. Most of the combinations that achieved either excellent or acceptable masking ability were obtained with combinations composed of one or two coats of opaquer and a 1.0-mm-thick resin composite layer for all backgrounds except C4. Acceptable results were also obtained for combinations with 0.5-mm-thick resin composite over C2, A3, and A3.5 backgrounds.

Color stability of resin composites for orthodontic attachments: an in vitro study.

OBJECTIVE: The aim of the present study was to evaluate the color stability of Filtek Z350 XT, Filtek Z250 XT, Z100 resin composites and Transbond XT orthodontic resin, all used in orthodontic attachments, when immersed in popular beverages. METHODS: Thirty disk-shaped specimens of each resin composite (2 x 5mm) were manufactured and randomly divided into six groups according to immersion solutions: coffee, red wine, white wine, regular beer, dark beer and deionized water (control). The specimens were fully immersed in each of the solutions for six days at 37°C, representing approximately six months of consumption. The color measurements were evaluated by a reflection spectrophotometer, at baseline (before immersion) and after staining. L*a*b* coordinates were measured and the color change (ΔE00) was calculated using the CIEDE2000 formula. The data were analyzed by ANOVA/Tukey tests at a significance level of 0.05. RESULTS: The resin composites immersed in white wine and regular beer showed either imperceptible or clinically acceptable ΔE00, and no difference from the control group (p= 0.4449 and p= 0.467 respectively). Immersion in coffee and red wine were considered clinically unacceptable and were significantly different from the control group (p= 0.0028 and p= 0.0475 respectively). CONCLUSION: Based on the results of the present study, the consumption of coffee and red wine may cause color change of the resin composite attachments above the visual acceptability threshold, and impair aesthetics during treatment.

O uso de smartphones como ferramenta de aprendizado por estudantes de Odontologia / The use of smartphones as a learning tool by dental students

As tecnologias podem ser potentes facilitadoras do processo de aprendizagem dos alunos, principalmente nas gerações atuais. Os smartphonessão ferramentas rotineiramente utilizadas a qualquer momento e em qualquer lugar na busca de variadas informações. Assim, a aquisição de conhecimento por meiodeste dispositivo móvel, alinhada com as perspectivas de ensino e resultados esperados para o aprendizado, parece fazer cada vez mais sentido. Neste contexto, este estudo foi proposto com o objetivo de conhecer o perfil do uso de smartphones como ferramenta de aprendizagem ativa e móvel por estudantes de Odontologia. Trata-se de um estudo transversal, realizado por meiode um questionário eletrônico, composto por perguntas objetivas e abertas, as quais avaliaram características sociodemográficas, tipo de aparelho e conexão, usogerale para aprendizado odontológico, bem como aatitude dos alunos em relação ao uso. Do total de estudantes elegíveis ao estudo, 169 alunos responderam ao questionário (taxa de resposta de 49,1%). A maioria dos participantes eram mulheres, com faixa etária de 19 a 21 anos. Todos os estudantes afirmaram ter smartphone, com conexão à internet. Os principais usos descritos foram relacionados à comunicação, gerenciamento de tempo e educação. As vantagens relatadas foram praticidade, flexibilidade de uso, acesso a diferentes conteúdos, capacidade de pesquisar informações e de se comunicar rapidamente. Os desafios identificados incluíram distração e excesso de uso. Os resultados permitiram concluir que os estudantes utilizam os smartphonescomo ferramenta de aprendizagem ativa, principalmente, para acessar e-books, artigos científicos, escutar podcasts,assistir livese visualizar publicações de conteúdos teóricos e práticos no Instagram (AU).

Technologies can be powerful and helpful tools for students' learning process, especially for the current generations. Smartphones are routinely used to search for a wide rangeof information, at anytime and anywhere. Thus, knowledge acquisition through this mobile device, for teaching and learning outcomes, seems to increasingly make more and more sense. Therefore, the aim of thisstudy was to understand the profile of the use of smartphones as an active learning tool by dental students. The data of this cross-sectional study was collected by an electronic questionnaire, with open and closed questions regarding the socio-demographic characteristics, type of device and connection, general use for dentallearning, as well as the students' attitudes towards the use of smartphone for learning. Out of the total number of students eligible for the study, 169 students responded to the questionnaire (response rate of 49.1%). Most participants were women, aged between 19 and 21 years. All students declaredtohave a smartphone, with internet connection. The main uses described were related to communication, time management,and education. The advantages pointed out by the participants were convenience, flexibility of use, access to different contents in different ways, ability to search for information,and rapid communication. The main challenges included distraction and overuse. The results of this study demonstrate that students use smartphones as an active learning tool, mainly to access e-books, scientific articles, to listen to podcasts, watch lives,and view publications of theoretical and practical content on Instagram (AU).

Effectiveness and color stability of bleaching techniques on blood-stained teeth: An in vitro study.

OBJECTIVE: Evaluate the effectiveness and color stability of bleaching techniques on blood-stained teeth. MATERIAL AND METHODS: The teeth were stained by blood and allocated to groups: walking bleach, inside/outside, and in-office bleaching. L*, a*, b*, C*, h° color coordinates were measured using a clinical spectrophotometer at baseline, weekly (T1-T2-T3), and at 1-week (T4), 6-months (T5), and 1-year (T6) follow-up evaluations. ΔEab* , ΔE00 , and ΔWID were calculated between sequential evaluation timepoints and between baseline and each evaluation timepoint. Color coordinates and WID differences in each timepoint and technique were analyzed by Wilcoxon Signed Rank, Kruskal-Wallis and Mann-Whitney U test, respectively. ΔEab* , ΔE00 , and ΔWID were interpreted by color visual thresholds. RESULTS: The techniques presented a significant increase in L* and WID and, a significant decrease in a* and b* until the completion of treatments. Statistical differences between the techniques for a*, b* and WID were observed from T1 until T3. All techniques demonstrated excellent effectiveness for ΔEab* , ΔE00 , and ΔWID between baseline and each evaluation and follow-up timepoints. However, at T6, it was possible to identify a rebound effect for all techniques. CONCLUSIONS: All bleaching techniques presented excellent effectiveness. The stability of the whitening produced was maintained for 6 months. CLINICAL SIGNIFICANCE: Effective whitening of blood-stained teeth was achieved using walking bleach (sodium perborate), inside/outside (hydrogen peroxide - 7.5%) and in-office techniques (hydrogen peroxide - 35%). The bleaching techniques were effective after the completion of the treatments. A slight rebound was observed at 1 year follow-up.

Masking ability of bleach-shade resin composites using the multilayering technique.

OBJECTIVE: Evaluate the masking ability of bleach-shade resin composites applied by multilayering techniques over colored substrates. MATERIALS AND METHODS: Disc-shaped specimens were fabricated from bleach-shade resin composites using different multilayering techniques. Substrates were produced in opaque ceramic discs simulating colored substrates (A2, A3, A3.5, C2, C3, C4) and a bleached tooth (0M1). Color coordinates were obtained using a reflectance spectrophotometer. Color difference was calculated by CIEDE2000 using coordinates of 0 M1 ceramic as standard reference. Data were analyzed by one-way ANOVA and Tukey's post-hoc test (p ≤ 0.05). Masking ability interpretation was based on perceptibility and acceptability thresholds. RESULTS: All combinations presented ΔE00 above the acceptable threshold (ΔE00 >1.8), ranging from 2.49 to 7.42, regardless of the restorative system, multilayering strategy or substrate color. Multilayering combinations placed over A2, A3 and A3.5 were moderately (1.8<ΔE00 ≤3.6) and clearly unacceptable (3.6<ΔE00 ≤5.4), combinations associated with C2, C3 and C4 were clearly unacceptable and, extremely unacceptable (ΔE00 >5.4). Lower ΔE00 was observed for combinations with 0.5 mm extra white enamel layer (2.49), or 1.0 mm white dentin layer (2.69), over A2 and A3.5 substrates. Lightness difference showed the greatest contribution to ΔE00 . CONCLUSIONS: Bleach-shade resin composite systems applied by the multilayering technique were not able to ensure effective masking ability. CLINICAL SIGNIFICANCE: Bleach-shade resin composites applied with different combinations of the multilayering technique were not effective in masking colored substrates. Alternative strategies, techniques and dental materials should be explored to obtain acceptable masking.

Effect of different placement techniques on color stability and surface roughness of resin composites / Efeito das técnicas de inserção e alisamento na estabilidade de cor e rugosidade superficial de resinas compostas

Abstract Introduction Longevity and clinical success of dental restorations can be influenced by many factors during the restorative procedures. Objective This study aimed to evaluate the influence of different placement techniques on color stability and surface roughness of two resin composites. Material and method The groups of specimens (n=10) were divided according to resin composite (FiltekTM Z250 XT and FiltekTM Z350 XT) and placement technique: Mylar strip, spatula, dry brush, modeling liquid, and surface sealant. Color stability and surface roughness were accessed using a spectrophotometer (CIELab color space) and a rugosimeter (standard cutoff of 0.8 mm), respectively, after water storage. Subsequently, the specimens were immersed in coffee for 48 h and final color was measured. The data were analyzed using ANOVA and the Tukey's post hoc test (α=5%) and the correlation between surface roughness (Ra) and color change (∆Eab) was assessed using the Pearson's correlation coefficient. Result The different placement techniques influenced Ra and ∆Eab on both resin composites. The groups treated with surface sealant showed greater difference in ∆Eab for both resin composites. The FiltekTM Z250 XT resin showed greater color stability compared with the FiltekTM Z350 XT resin regardless of the placement technique used. Ra of each placement technique was similar among the resin composites except for the FiltekTM Z350 XT modeling liquid group, which presented lower Ra values compared with those of FiltekTM Z250 XT. A correlation between Ra and staining was identified (p=0.268). Conclusion Color stability and Ra are influenced by different placement techniques.

Resumo Introdução A longevidade e o sucesso clínico das restaurações dentárias podem ser influenciados por muitos fatores durante os procedimentos restauradores. Objetivo Avaliar a influência da técnica de alisamento na estabilidade de cor e rugosidade superficial de duas resinas compostas. Material e método Os grupos de amostras (n=10) foram divididos conforme a resina composta (FiltekTM Z250 XT e FiltekTM Z350 XT) e as técnicas empregadas: tira de poliéster, espátula, pincel seco, selante de superfície. A cor e a rugosidade da superfície foram avaliadas por espectrofotômetro (espaço de cor CIELab) e rugosímetro (corte padrão de 0,8 mm), respectivamente, após o armazenamento em água. Posteriormente, as amostras foram imersas em café por 48h e a cor final foi aferida. Os dados foram analisados usando teste ANOVA e Tukey post hoc (α = 5%) e a correlação entre rugosidade da superfície (Ra) e variação de cor (∆Eab) através do coeficiente de correlação de Pearson. Resultado As técnicas de alisamento influenciaram a Ra e a ∆Eab em ambas as resinas compostas. Os grupos tratados com selante de superfície apresentaram maior diferença na ∆Eab. A resina FiltekTM Z250 XT apresentou maior estabilidade de cor comparada à FiltekTM Z350 XT, independentemente da técnica utilizada. A Ra das técnicas de alisamento foi semelhante entre os compósitos, exceto para o grupo do líquido modelador da FiltekTM Z350 XT, que apresentou os menores valores. Uma correlação entre Ra e manchamento (p = 0,268) foi identificada. Conclusão A estabilidade da cor e a Ra são influenciadas pelas técnicas de alisamento utilizadas.

Marginal staining of ultra-thin ceramic veneers

The pigmentation of the resin cement at the tooth/ceramic interface compromises the esthetic and longevity of ultra-thin ceramic veneers. Aim: The aim of this study was to evaluate marginal staining of ultra-thin ceramic veneers cemented to intact enamel (non-prepared) and prepared enamel. Methods:Thirty-two (32) permanent central incisors were selected and randomly divided into two groups: intact enamel (IE) and prepared enamel (PE). The ceramic veneers of PE group were bonded to the prepared enamel and the ceramic veneers of IE group were cemented directly onto the intact enamel, with no preparation. Both preparation and cementation were standardized and performed by a single operator. Each group was subdivided into two subgroups (n = 8) with different immersion media - coffee and water. After an immersion period of 10 days, stereomicroscope images were made at 20X magnification of the mesial, distal, cervical and incisal surface of each specimen. Three blinded, trained and calibrated examiners evaluated the images of the resin cement interface of each surface. The data were subjected to KruskalWallis and MannWhitney statistical analysis. Immersion media and enamel preparation influenced the marginal staining of the tooth/ceramic interface. Results: When immersed in coffee, prepared interfaces presented greater marginal staining than unprepared interfaces. When immersed in water, there was no statistically significant difference between the groups. Conclusion: The cementation of ultra-thin ceramic veneers onto intact enamel is associated with less marginal staining and, consequently, improved esthetics

The effect of immediate and delayed polishing on the color stability of a composite resin.

Polishing techniques are known to enhance the longevity and appearance of composite resin restorations. However, the influence of the timing of polishing on the final results of a restoration is not well documented. The aim of this study was to determine the effect of immediate and delayed polishing on the color stability of a composite resin. Sixty composite resin specimens were fabricated and randomly divided into 2 groups according to immersion solutions: group 1, deionized water (control); and group 2, coffee (as staining solution). The groups were further divided according to polishing time periods (immediate, 1 day, 7 days, 14 days, and 21 days). The polishing was performed by 1 calibrated operator using a sequence of aluminum oxide discs with different granulations. Color measurements were assessed at baseline and after a 48-hour immersion in the assigned medium by a reflection spectrophotometer, according to CIE L*a*b* parameters. The data were submitted to an analysis of variance (ANOVA) and the post hoc Tukey test at a significance level of 0.05. The ANOVA showed that the immersion solutions had a statistically significant difference (α = 0.05) on color stability. The composite resin color stability was not influenced by the timing of polishing, and all subgroups showed clinically unacceptable discoloration after exposure to coffee. Thus, with regard to color stability, the timing of final polishing may be established according to the preferences of the clinician.

Evaluation of the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques / Avaliação da rugosidade superficial de uma resina nanoparticulada submetida a diferentes técnicas de alisamento e finalização

Introduction: Controlling the surface smoothness characteristics of the composite resin when performing a direct restorative technique is one of the factors involved in achieving restorative success. Objective: The purpose of this study was to evaluate the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques. Material and method: Fifty test specimens were made with the Z350 XT composite resin (3M ESPE) and then divided into five study groups according to the smoothing and finishing method applied, as follows: G1 (control), polyester strip; G2, composite spatula; G3, brush cleaned with absolute alcohol and dried; G4, brush cleaned with absolute alcohol, dried and moistened with Single Bond (3M ESPE); and G5, brush cleaned with absolute alcohol, dried and moistened with Natural Glaze surface sealant (DFL). After fabrication, the specimens were stored for 24 h in deionized water. The surface roughness of the specimens was measured using a profilometer. Surface roughness means were compared by analysis of variance followed by Tukey’s test at a level of significance of 5%. Result: The lowest surface roughness was observed in G1 (control group) and the highest, in G3. G5 had lower surface roughness values compared to the other test groups, and presented values similar to those of the control group. Conclusion: The smoothing and finishing techniques influenced the surface roughness of the composite resin. Application of the surface sealant by the copolymerization technique resulted in lower roughness values. The use of a clean, dry brush promoted roughness values beyond the acceptable limit, and is therefore liable to compromise the performance of composite resin restorations.

Introdução: O controle da técnica restauradora direta com resina composta no que se refere às características de lisura superficial, é um dos fatores que deve ser considerado para o sucesso restaurador. Objetivo: O propósito deste estudo foi avaliar a rugosidade superficial de uma resina composta nanoparticulada submetida a diferentes técnicas de alisamento e finalização. Material e método: Cinquenta corpos de prova foram confeccionados utilizando a resina composta Z 350 XT (3M ESPE), divididos em cinco grupos sendo: G1 (controle): padrão tira de poliéster; G2: espátula para inserção de resina; G3 pincel limpo com álcool e seco; G4; pincel limpo com álcool, seco e umedecido com adesivo Single Bond (3M ESPE); e, G5: pincel limpo álcool, seco e umedecido com selante de superfície Natural Glaze (DFL). Após a confecção os corpos de prova foram estocados por 24 horas em água deionizada. A rugosidade superficial foi mensurada por meio de um rugosímetro de precisão. As médias foram comparadas por análise de variância, seguida do Teste de Tukey a 5% de significância. Resultado: A menor rugosidade superficial foi observada em G1 e a maior em G3 O grupo G5, apresentou valores de rugosidade superficial inferiores aos demais grupos testados e próximos ao grupo controle. Conclusão: As técnicas de alisamento e finalização influenciaram a rugosidade superficial da resina composta. O uso de selante resinoso, pela técnica de copolimerização, resultou em menor rugosidade e o emprego do pincel limpo e seco promoveu rugosidade, além do limite aceitável o que pode comprometer o desempenho de restaurações.

Effect of a surface sealant on the color stability of composite resins after immersion in staining solution.

This study evaluated the influence of surface sealants on the color stability of 2 different composite resins after immersion in coffee. Four groups were created (n = 10): microhybrid composite, microhybrid with surface sealant, nanofilled composite, and nanofilled composite with surface sealant. Half of the specimens of each group were immersed in distilled water and half were immersed in coffee for 48 hours. Color was measured before and after immersion. Groups with surface sealants presented less color variation when compared with the groups without surface sealants. The nanofilled resin specimens presented the greatest color variation within the groups without sealant. The surface sealant positively influenced the color stability of composite resin specimens immersed in coffee. When surface sealant was not applied, the microhybrid specimens had better color stability than the nanofilled.

Tratamento estético de lesões não cariosas: série de casos / Aesthetic treatment of non-carious lesions: a case series

As lesões não cariosas têm sido frequentemente motivo de queixa de pacientes odontológicos, sobretudo quando elas têm implicações estéticas. A etiologia desses desgastes é multifatorial, sendo proveniente de processos mecânicos, que determinam desgaste por atrição, abrasão e abfração, e químicos, como a erosão. O aumento da incidência de lesões desse tipo direcionou maior atenção ao diagnóstico multidisciplinar e levou ao desenvolvimento de novas opções de terapias restauradoras minimamente invasivas. A presente série de casos de busca apresentar uma opção conservadora e multidisciplinar, desde o diagnóstico ao tratamento e proservação de desgastes dentários de diversas etiologias, com especial atenção para a estética e saúde geral do paciente...

Non-carious lesions have increasingly become a cause of patients complaint, especially when aesthetic implications are involved. The etiology of non-carious tooth wear is multifactorial. Mechanical processes which produce wear by attrition, abrasion and abfraction, and chemicals factors which produce tooth loss by erosion. The increasing incidence of these lesions led to a greater attention to multidisciplinary diagnosis and the development of new options of minimally invasive restorative therapies. This case series aims to presents a conservative and multidisciplinary approach, from diagnosis to treatment and proservation of tooth wear of various etiologies, with special attention to the aesthetics and patient’s general health...

Modeling and validation of a 3D premolar for finite element analysis / Modelagem e validação 3D de um premolar para análise de elementos finitos

Introduction: The development and validation of mathematical models is an important step of the methodology of finite element studies. Objective: This study aims to describe the development and validation of a three-dimensional numerical model of a maxillary premolar for finite element analysis. Material and method: The 3D model was based on standardized photographs of sequential slices of an intact premolar and generated with the use of SolidWorks Software (Dassault, France). In order to validate the model, compression and numerical tests were performed. The load versus displacement graphs of both tests were visually compared, the percentage of error calculated and homogeneity of regression coefficients tested. Result: An accurate 3D model was developed and validated since the graphs were visually similar, the percentage error was within acceptable limits, and the straight lines were considered parallel. Conclusion: The modeling procedures and validation described allows the development of accurate 3D dental models with biomechanical behavior similar to natural teeth. The methods may be applied in development and validation of new models and computer-aided simulations using FEM.

Introdução: O desenvolvimento e validação de modelos matemáticos é uma importante etapa da metodologia de estudos de elementos finitos. Objetivo: Este estudo tem o objetivo descrever o desenvolvimento e validação de um modelo numérico tridimensional de um pré-molar superior para análise em elementos finitos. Material e método: Fotografias padronizadas de cortes sequenciais de um pré-molar hígido serviram de referência para o desenvolvimento do modelo 3D, que foi construído por meio do programa SolidWorks (Dassault, França). A fim de validar o modelo testes de compressão e simulação numérica foram realizados. Os gráficos de carga versus deslocamento de ambos os ensaios foram comparados visualmente, a percentagem de erro calculada e homogeneidade dos coeficientes de regressão testada. Resultado: Um modelo 3D preciso foi desenvolvido e validado, uma vez que os gráficos apresentavam-se visualmente semelhantes, o percentual de erro ficou dentro dos limites aceitáveis e as retas foram consideradas paralelas. Conclusão: Os procedimentos de modelagem e validação descritos permitem o desenvolvimento de modelos dentários 3D precisos com comportamento biomecânico semelhante aos dentes naturais. Os métodos podem ser aplicados no desenvolvimento e validação de novos modelos e estudos de simulações computacionais por meio do MEF.

Otimização estética de dentes conoides com facetas de porcelana: relato de caso / Esthetic otimization of peg shaped lateral incisors using porcelain veneers: a case report

Incisivos laterais conoides apresentam a coroa dental com dimensões reduzidas e formato cônico, prejudicando a harmonia do sorriso. As facetas de porcelana têm se mostrado uma opção restauradora estética, conservadora e com resultados duradouros para essas situações clínicas. O presente relato de caso descreve o tratamento multidisciplinar para a recuperação estética do sorriso. O tratamento consistiu no clareamento dental, confecção de facetas de porcelana e realização de cirurgia de aumento de coroa clínica. O resultado final demonstra melhora da estética do sorriso com procedimentos minimamente invasivos...

Peg-shaped lateral incisors have small-sized, conical-shaped tooth crowns, which compromise the harmony of the smile. Porcelain veneers are an esthetic and conservative restorative option for this situation, with long-lasting results. This clinical report describes a multidisciplinary treatment to reestablish the esthetic of the smile. The treatment comprised in tooth bleaching, porcelain veneers and crown lengthening surgery. The final result demonstrates improved aesthetics with minimally invasive procedures...

Effect of ceramic thickness and composite bases on stress distribution of inlays--a finite element analysis.

The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred.

Instrument of self-perception and knowledge of dental erosion: cross-cultural adaptation to the Brazilian population.

There are few instruments available in Brazil for obtaining data on dental erosion among adults. For this reason, the interview entitled "A Survey on Hong Kong People's Dietary Behavior in Relations to Acid Erosion", published in English, was considered for translation. The aim of this study was to perform a cross-cultural adaptation and content validation for the Brazilian population. After obtaining the author's permission, the interview underwent several stages: translation, back translation, review by a bilingual person and a committee of experts, administration of the English instrument and of the Portuguese version to a bilingual group, and pretesting in a convenience sample of 50 adults. The interview was translated and adapted to the Portuguese language and the Brazilian culture. The analysis of the data revealed that the interview was easy to apply, conduct and understand; therefore, it was considered viable and capable of being used in different studies.

Effect of Ceramic Thickness and Composite Bases on Stress Distribution of Inlays - A Finite Element Analysis

The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred.

O objetivo do estudo foi avaliar o efeito da profundidade da cavidade, da espessura da cerâmica e da presença de bases de resina, com os diferentes módulos de elasticidade na distribuição de tensões de von Mises em inlays cerâmicos. Modelos geométricos tridimensionais foram desenvolvidos com o software SolidWorks. As diferenças entre os modelos foram: a profundidade da parede pulpar, a espessura da cerâmica e a presença de bases de resina composta com diferentes espessuras e módulos de elasticidade. Os modelos geométricos foram engastados nas superfícies proximais e base do osso maxilar e uma carga de 100 Newton foi aplicada. O padrão de distribuição de tensões foi analisado com diagramas de tensão de von Mises. O valor de tensão máxima de von Mises foi variável entre os modelos e situou-se na faixa entre 176 e 263 MPa. O maior valor foi encontrado nos modelos restaurados com bases de resina composta de 1 mm e inlay cerâmico de 1 mm de espessura. Valores intermediários (249-250 MPa) ocorreram nos modelos com bases de resina composta de 2 mm e inlays de 1 mm de espessura e nos modelos com bases de resina composta de 1 mm e inlays de 2 mm. Os menores valores foram observados nos modelos restaurados exclusivamente com inlay cerâmico (176-182 MPa). Verificou-se que inlays com maior espessura distribuem o estresse de forma mais favorável e bases com baixo módulo de elasticidade aumentam a concentração de tensões na superfície interna do inlay de cerâmica. O aumento da espessura do material cerâmico tende a apresentar uma distribuição de tensões mais favorável, principalmente quando cimentadas diretamente sobre o preparo cavitário, sem a existência de materiais intermediários. Em situações em que o emprego de materiais de base é necessária, deve-se preferir resinas compostas com alto módulo de elasticidade e espessura reduzida.

Instrument of self-perception and knowledge of dental erosion: cross-cultural adaptation to the Brazilian population

There are few instruments available in Brazil for obtaining data on dental erosion among adults. For this reason, the interview entitled “A Survey on Hong Kong People’s Dietary Behavior in Relations to Acid Erosion”, published in English, was considered for translation. The aim of this study was to perform a cross-cultural adaptation and content validation for the Brazilian population. After obtaining the author’s permission, the interview underwent several stages: translation, back translation, review by a bilingual person and a committee of experts, administration of the English instrument and of the Portuguese version to a bilingual group, and pretesting in a convenience sample of 50 adults. The interview was translated and adapted to the Portuguese language and the Brazilian culture. The analysis of the data revealed that the interview was easy to apply, conduct and understand; therefore, it was considered viable and capable of being used in different studies.