Influence of pH-cycling and abrasion wear on the mechanical properties of conventional and bulk fill resin composites

The objective of this study was to evaluate the effect of abrasion wear on surface roughness and microhardness of different commercially available resin composites simulating pH-challenges of the oral cavity. Methods: Three resin composites (RC) were used in this study: one conventional: Z250; and two bulk fill resin composites (BRC): Tetric N-Ceram (TNC) and Sonic Fill (SF). The RC was inserted in a prefabricated mold (15mm wide x 4mm thickness) in two layers, or in a single layer for BRC. Thirty samples were prepared and surface roughness (Ra) and Knoop microhardness (KHN) test were performed at three different time-points of evaluation: baseline (24h after sample preparation); partial (after pH cycling); and final (after simulated toothbrushing procedure). Two samples of each group were selected after different treatments and analyzed descriptively on a scanning electron microscopy (SEM). Data from Ra and KHN were analyzed by two-way repeated-measures ANOVA and Bonferroni's post-hoc test with a significance level set at 5%. Results: Ra increased for all groups (p<0.001), at the final time-point, Z250 and TNC groups present the highest values. Oppositely, KHN decreased for all groups (p<0.001), Z250 group showed the highest KHN values for all time-points (p<0.001). The SEM imagens showed a regular surface for samples cycled and irregular with inorganic particles exposed for samples toothbrushed. Conclusion: pH-cycling and simulated toothbrushing affected the superficial properties (roughness and Knoop microhardness), as observed at SEM imagens, with irregular surface with inorganic particles exposure

Do Bulk-Fill Resin Composites Present More Susceptibility to Marginal Degradation in Different Clinical Scenarios? A Systematic Review and Meta-Analysis

Abstract Objective: To compare the marginal degradation (susceptibility to marginal adaptation and marginal discoloration) of composite restorations placed in class II and V cavities using conventional and bulk-fill resin composites. Material and Methods: This study was approved by PROSPERO database (#42020201596). PubMed, Scopus, Embase, Web of Science, Lilacs, Cochrane, Open Grey, Clinical Trials, and Rebec databases were searched by three independent investigators using MeSH terms, supplementary concepts, synonyms, and free keywords, based on the PICOS strategy (P, population: restoration in permanent teeth; I, intervention: bulk-fill resin composite; C, comparison: conventional resin composite; O, outcome: marginal discoloration and adaptation; and S, study design: randomized and non-randomized clinical trials). The risk of bias was evaluated according to the Cochrane Collaboration's tool, the meta-analyses by RevMan software, the certainty of evidence by the Grading of Recommendations Assessment, Development, and Evaluation, and the leave-one-out sensitivity test. The prevalence of successful events and the total number of restorations were used to calculate the risk difference at a confidence interval of 95%, according to a fixed-effect model. The heterogeneity was evaluated using the I2 index. Results: 16 from 10,780 studies were selected and included for qualitative and quantitative analysis. Two studies were considered as high risk of bias, one showing some concerns, and 13 as low risk of bias. Four meta-analyses evaluated the marginal adaptation and marginal discoloration in class II and V cavities, with a nonsignificant heterogeneity (I2 = 0%, p>0.05). The certainty of evidence was considered high, except for two subgroups of each outcome. Conclusion: There is evidence that composite restorations using conventional and bulk-fill resin composites present similar clinical performance related to marginal degradation (AU).

The finish line location of the cemented crown is an influencing factor for tensile bond strength, marginal adaption and nanoleakage? / A localização do término marginal em coroas cimentadas é um fator que influencia a resistência à tração, adaptação marginal e nanoinfiltração?

Objective: The aim of this study was to evaluate the influence of different crowns finishing line location on the crown tensile bond strength, marginal adaption and nanoleakage. Material and Methods: Sixty healthy third molars were collected. For tensile bond strength, a self-adhesive resin cement was used. For marginal adaption, epoxy resin models were prepared. Prior to tensile bond strength test, images for the epoxy resin models were measured under scanning electron microscopy (SEM). Nanoleakage was measured using same protocol. Failure mode was evaluated through SEM and classified: adhesive failure, cohesive in cement, cohesive in dentin, cohesive in resin composite, cohesive in enamel, and mixed. Statistical analysis was performed using Shapiro-Wilk and Kolmogorov Smirnov normality tests, two-way ANOVA, Bonferroni (posthoc) parametric test, with significance level of 5% (P < .05), Spearman correlation test. Results: tensile bond strength was not statistically different between the cemented groups with composite resin and ceramic. Cementation of ceramic was not statistically different between the groups (enamel, 3.28 Pa; dentin, 3.14 Pa; resin, 2.85 Pa). Marginal adaption was statistically different between resin and ceramic; finish line location varied between enamel and resin (175.91 µm vs. 433.58 µm). Nanoleakage rate was statistically different among all groups, except for resin: with resin (9.49%) and ceramic (9.35%). There was a predominance of adhesive failure in all groups. Conclusion: finish line location can be performed safely in enamel and dentin. Composite resinas substrate present an alternative, but still need to be more studied. Regarding the crown's material, it is possible to perform a satisfatory restoration in both: resin and ceramic. With ceramics presenting better results. (AU)

Objetivo: O objetivo deste estudo foi avaliar a influência da localização do término marginal na cimentação de coroas, na resistência à tração, adaptação marginal e nanoinfiltração, de acordo com os fatores: término marginal (dentina, esmalte e resina composta), e material restaurador (resina composta e cerâmica). Material e Métodos: Foram coletados 60 terceiros molares hígidos. Para o teste de resistência à tração, todas as amostras foram praparadas com término em chanfro e um cimento resinoso autoadesivo foi utilizado para a cimentação. Para a avaliação da adaptação marginal, foram confeccionados modelos em resina epóxica da linha de cimentação das amostras, previamente ao teste de tração, e submetidas à avaliação em microscopia eletrônica de varredura (MEV), para obtenção de imagens que posteriormente foram mensuradas. Para a nanoinfiltração, foram confeccionados fragmentos dos substratos e materiais restauradores, que foram cimentados com o mesmo protocolo. As amostras/imagens foram obtidas em MEV e mensurada a área infiltrada. O padrão de fratura foi avaliado através de imagens obtidas no MEV e classificados em: falha adesiva, coesiva em cimento, coesiva em dentina, coesiva em resina composta, coesiva em esmalte e mista. A análise estatística foi realizada utilizando os testes de normalidade Shapiro-Wilk e Kolmogorov Smirnov, ANOVA a dois fatores, teste paramétrico Bonferroni (post-hoc), com nível de significância de 5% (P <0,05), teste de correlação de Spearman. Resultados: a resistência à tração não foi estatisticamente diferente entre os grupos cimentados com resina composta e cerâmica. A cimentação da cerâmica não foi estatisticamente diferente entre os grupos (esmalte, 3,28 Pa; dentina, 3,14 Pa; resina, 2,85 Pa). A adaptação marginal foi estatisticamente diferente entre resina e cerâmica; a localização da linha de chegada variou entre esmalte e resina (175,91 µm vs. 433,58 µm). Para a nanoinfiltração foi estatisticamente diferente entre todos os grupos, exceto a resina: com resina (9,49%) e cerâmica (9,35%). Houve predomínio de falha adesiva em todos os grupos. Conclusão: a localização da linha de chegada pode ser realizada com segurança no esmalte e dentina. O substrato em resina composta apresenta uma alternativa promissora, mas ainda precisa ser mais estudado. Em relação ao material da coroa, é possível realizar uma restauração satisfatória tanto em resina composta quanto em cerâmica. Sendo a cerâmica, o material que apresentou melhores resultados. (AU)

Glass fiber posts: influence of cementation techniques on push-out bond strength

Aim: Glass fiber posts are indicated in the rehabilitation of extensively damaged teeth; their cementation represents a critical step in restorative dentistry. The aim of this study was to quantify and compare the push-out bond strength of glass fiber posts cemented by conventional technique, two-step technique with luting agent and two-step technique associating bulk-fill composite and luting agent. Methods: Eighty maxillary bovine incisors were endodontically treated and divided into eight groups (n = 10) according to the luting agent (Rely X ARC and Duo-link) and cementation technique (conventional technique; two-step technique with luting agent; and two-step technique associating bulk-fill composite ­ Filtek Bulk-fill flow or Surefil SDR flow ­ and luting agent). Samples were submitted to pushout bond strength test, and the fracture pattern was evaluated through scanning electron microscope. Data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Results: When Rely X ARC was used, the conventional cementation technique obtained higher bond strength values than the twostep technique associated with Filtek Bulk-fill flow. When Duolink was used, the two-step technique associated with Filtek Bulk-fill flow presented higher bond strength values than the conventional technique. The most prevalent fracture patterns were adhesive between luting agent and dentin, and adhesive between bulk-fill composite and dentin. Conclusion: Two-step cementation technique associated with bulk-fill composite may be promising depending on the luting agent used

Influence of three treatment protocols for dental fluorosis in the enamel surface: an in vitro

Introduction: Dental fluorosis is an enamel alteration characterized with opaque stains caused by high exposures to fluoride during the dentition development. Aim : This in vitro study aimed to evaluate changes in the enamel surface of sound human teeth after three treatment protocols for dental fluorosis: microabrasion with 37% phosphoric acid and pumice, home bleaching with 10% carbamide peroxide, and a combination of these techniques. Methods : Thirty-eight specimens (5×5×2 mm) with enamel surface were obtained from 19 third molars. Thirty six specimens were randomized into three treatment groups (n= 12): MAB- enamel microabrasion; CP10- home bleaching; MAB+CP10- a combination of these techniques and two specimens not received treatment. Surface roughness and microhardness analyses were performed before and after treatment protocols. Two representative specimens from each group were evaluated by scanning electron microscopy (SEM). Analysis of variance and Tukey's tests were used for data analysis (p< 0.05). Results : All treatment protocols promoted an increased in enamel surface roughness (p< 0.02). MAB and MAB+CP10 showed a significant increase in the enamel microhardness (p< 0.04), while CP10 showed a microhardness lower than MAB and MAB+CP10 (p< 0.05). SEM images demonstrated a smoother surface from MAB and MAB+CP10 and, an irregular pattern of enamel erosion from CP10. Conclusions : The treatment protocols for dental fluorosis tested significantly changed the enamel roughness, microhardness and micromorphology.

Introdução: A fluorose dentária é uma alteração do esmalte caracterizada por manchas opacas causadas pela alta exposição aos íons fluoreto durante o desenvolvimento dentário. Objetivo : Este estudo in vitro objetivou avaliar mudanças na superfície do esmalte em dentes humanos hígidos após três protocolos de tratamento para a fluorose dentária: microabrasão com ácido fosfórico a 37% e pedra-pomes, clareamento caseiro com peróxido de carbamida a 10% e a associação destas técnicas. Métodos : Trinta e oito espécimes (5×5×2 mm) com superfície em esmalte foram obtidos a partir de 19 terceiros molares, sendo que dois não receberam tratamento e, trinta e seis foram randomizados em três grupos (n= 12): MAB- microabrasão do esmalte; CP10- clareamento caseiro; e MAB+CP10- associação destas técnicas. A rugosidade superficial e microdureza foram realizadas antes e após os protocolos de tratamento. Dois espécimes representativos de cada grupo foram avaliados por microscopia eletrônica de varredura (MEV). A análise de variância e teste de Tukey foram utilizados para análise dos resultados (p< 0,05). Resultados : Todos os protocolos de tratamento promoveram um aumento da rugosidade superficial do esmalte (p< 0,02). MAB e MAB+CP10 mostraram um aumento significativo da microdureza do esmalte (p< 0,04), enquanto que CP10 mostrou uma menor microdureza comparado ao MAB e ao MAB+CP10 (p< 0,05). As imagens de MEV demonstraram uma superfície mais lisa do MAB e MAB+CP10 e um padrão irregular do esmalte erodido para o CP10. Conclusão : Os protocolos testados para tratamento da fluorose dentária testados modificaram significativamente a rugosidade, microdureza e micromorfologia do esmalte.

Qualidade de vida de pacientes submetidos à exodontia de terceiros molares / Quality of life in patients undergoing third molar extraction

Introdução: A remoção dos terceiros molares pode causar transtornos e prejuízos à qualidade de vida. Objetivo: Avaliar a qualidade de vida de pacientes submetidos à exodontia de terceiros molares, discutindo os eventos mais comumente observados. Material e Método: Sessenta pacientes de uma Clínica Privada de Cirurgia, da cidade de João Pessoa-PB, foram submetidos à exodontia de terceiros molares, pelo mesmo operador e em condições semelhantes. Os dados foram coletados em duas etapas: a primeira foi realizada no dia do procedimento, quando foram anotados os dados do paciente, assim como as informações relacionadas à cirurgia. A segunda etapa foi realizada sete dias após o procedimento, quando os pacientes responderam o formulário acerca da qualidade de vida durante o pós-operatório. Resultado: 71,4% dos pacientes submetidos a Osteotomia e Odontossecção mantiveram suas atividades normais, e 28,6% não mantiveram. No entanto, quanto aos pacientes não submetidos às técnicas, 40,9% mantiveram suas atividades normais e 59,1% não mantiveram. De acordo com a classificação de Pell & Gregory, percebeu-se que 71,4% dos pacientes Classe 3 mantiveram suas atividades sociais normalmente, enquanto 60% dos pacientes Posição C não as mantiveram. Dos pacientes que se isolaram socialmente e foram submetidos às técnicas, 71,4% relataram a dor como o principal motivo, e 100% dos pacientes Classe 3 e 80% dos pacientes Posição C optaram pela mesma resposta. Conclusão: Os resultados indicam que as técnicas empregadas no transoperatório não interferem na qualidade de vida do paciente durante o pós-operatório e a posição tem maior influência do que a classe, no que se refere ao desenvolvimento normal das atividades sociais. .

Introduction: The removal of third molars can cause disorders and damage in quality of life. Objective: This study aimed to evaluate the quality of life in patients underwent surgery, discussing the most commonly events observed. Material and Method: Sixty patients of a private surgery clinic from João Pessoa/PB were underwent extraction of third molars by the same surgeon and and under the same conditions. Data were collected in two steps: the first one was accomplished at the day of the procedure, which were noted down both patient and surgery informations. The second step were realized seven days after the procedure, the patients answered a form about life quality at the postoperative period. Result: 71,4% patients underwent to osteotomy and odontosection maintained their normal activities and 28,6% did not. While in patients not submitted to the techniques, 40,9% maintained their normal activities and 59,1% did not. According to Pell & Gregory classification, 71,4% of patients Class 3 maintained normally their social activities, while 60% of patients Position C didn´t. Patients who remained socially isolated and were underwent to techniques, 71,4% reported as the main reason the pain, and 100% of patients Class 3 and 80% of patients Position C have chosen the same answer. Conclusion: The results suggest that the techniques used in the transoperative does not influence the quality of life during the postoperative and the position has more influence than the class, in respect to the development of normal social activities. .

Variações anatômicas que interferem no tratamento endodôntico - revisão da literatura / Anatomic variations affecting endodontic treatment – a review of the literature

O tratamento endodôntico visa restaurar a função e forma próprias do dente além de manter uma condição perirradicular saudável. No entanto, a ocorrência de variações na anatomia dental pode dificultar e/ou comprometer a eficácia do tratamento. Este estudo objetivou realizar uma revisão da literatura acerca das variações anatômicas que podem interferir no tratamento endodôntico. Foram encontrados diversos estudos contendo informações sobre variações anatômicas nos diferentes grupos de dentes e métodos auxiliares para diagnóstico. Desta maneira, se faz evidente a importância da detenção desse conhecimento para o sucesso da terapêutica endodôntica.

Endodontic treatment aims to restore tooth’s function and shape as well as maintaining a healthy periradicular condition. However, the occurrence of dental anatomy variations may difficult and/or compromise the efficacy of the treatment. The present study aimed toundertake a review of the literature on the anatomical variations, which may interfere with endodontic treatment. It was found several studies containing information about anatomical variations affecting different groups of teeth and auxiliary diagnostic methods. Thus, itbecomes evident the importance of such knowledge to endodontic treatment success.