Association between retainers choice in endodontically treated teeth and training level of professionals

This study assessed the knowledge and attitudes of graduate students and professionals on the use of retainers and luting agents. This cross-sectional study interviewed 150 undergraduate dental students and 150 dentists in the city of Pelotas, using a questionnaire. The questionnaire contained multiple-choice questions on used retainers choice/cement, degree of confidence to use glass fiber posts and resin cement in anterior and posterior teeth with large coronal destruction. Data were analyzed using descriptive analysis and tested combinations through Fisher's Exact test or chi-square with a significance level of 5%. The data about the use of glass fiber post and resin cement confidence level was ranked and submited to the T test. Eighty-seven percent of professionals and 51% of students had used retainers (P=0.00). For anterior teeth (P=0.00), dental students would mostly use glass fiber posts as the first choice, while for posterior teeth, cast metal cores (P=0.004). Regarding the type of cement to lutel cast metal posts, zinc phosphate was selected among dentists and students. As for glass fiber posts, professionals and students chose the self-adhesive resin cement. Public service dentists preferred glass fiber posts for anterior (P=0.023) and posterior teeth (P=0.00), while in the private service cast metal posts were selected. The clinical choices of dentists and students was related to their training level and type of service.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESO estudo avaliou o conhecimento e atitudes de alunos de graduação e profissionais quanto ao uso de retentores intra-radiculares e suas modalidades de cimentação.Este estudo transversal entrevistou 150 alunos de graduação e 150 cirurgiões-dentistas da cidade de Pelotas-RS, através de questionário. O questionário continha questões de múltipla escolha sobre retentores utilizados, cimentos resinosos, escolha de retentor/cimento, função dos retentores, grau de confiança para utilização de pinos de fibra de vidro e cimento resinoso em dentes anteriores e posteriores com grande destruição coronária. Os dados foram submetidos a análise descritiva e associações testadas através dos testes Exato de Fischer ou Qui-quadrado com um nível de significancia de 5%. Os dados sobre a grau de confiança para a utilização de pinos de fibra de vidro e cimento resinoso foram rankeados e submetidos ao teste T.Oitenta e sete porcento dos profissionais e 51% dos alunos já haviam utilizado retentores (P=0,00). Para dentes anteriores, dentistas e alunos em sua maioria utilizariam pino de fibra de vidro como primeira escolha (P=0,00), enquanto que para dentes posteriores, núcleo metálico fundido (P=0,004). Quanto ao tipo de cimento para núcleos metálicos fundidos o fosfato de zinco foi uma tendência entre os dentistas e alunos. Já para pinos de fibra de vidro, profissionais e alunos escolheram o cimento resinoso autoadesivo. Os dentistas do serviço público escolheram pinos de fibra de vidro para dentes anteriores (P=0,023) e dentes posteriores (P=0,00), enquanto que no serviço privado a escolha foi de núcleos metálico fundidos.As escolhas clínicas dos dentistas e alunos tem relação com o grau de formação e tipo de serviço prestado

Influence of the restorative material and restorative protocol on the physic-mechanical performance of endocrown restorations

The aim of this study was to investigate the influence of the type of restorative material (conventional resin composite or bulk-fill) and of the restorative technique (application or not of modeler liquid in-between the layers of resin composite, or the use or not of fiber-reinforced glass posts to increase the retention of the restorative material) on the physic-mechanical performance of endocrown restorations. The work was divided in four studies: (1) a systematic review and meta-analysis of literature aiming to investigate whether the dental position and the type of restorative technique (endocrown or with fiber-reinforced glass posts) would influence the fracture resistance of the restorations; (2 and 3) in vitro studies that evaluated whether the presence of a fluid resin material (modeler liquid) in between the layers of resin composite would improve the physic-mechanical performance and color/translucency stability of resin composite restorations; and (4) an in vitro study that evaluated the fatigue and fracture resistance of endocrown restorations, evaluating the influence of the type of restorative technique (direct or indirect) and of the restorative materials used. The first study was described according to the PRISMA Statement in order to verify the existence of differences concerning the fracture strength of teeth restored with endocrowns or glass fiber posts. The second study used methodologies of physic-mechanical and optical characterization of the experimental groups. Lastly, the fourth study simulated the performance of endocrown restorations prepared with ceramic, resin composites (conventional or bulk-fill) with or without modeler liquid; moreover, the restorations were prepared using direct or indirect techniques, which were submitted to mechanical fatigue testing. For statistical analysis, the data were analyzed with a 5% level of significance. The results of the meta-analysis showed that endocrowns had fracture strength similar to resin composite restorations. The results of the in vitro studies demonstrated that the presence of modeler liquid (resin adhesive) in-between the layers of resin composite improved the physic-mechanical performance of the material, with this effect being more pronounced for the modeler lquid with a hydrophobic composition. In conclusion, endocrown restorations can be satisfactorily used in the daily routine to reestablish the function and aesthetics of severely damaged non-vital teeth. Furthermore, it was possible to understand the physical and mechanical behavior of resin composites modeled using resin adhesives (modeler liquid), thereby contributing for the selection of the best restorative system and restorative technique for preparing endocrown restorations.Sem bolsaO objetivo deste trabalho foi verificar a influência do tipo de material restaurador (resina composta convencional ou de preenchimento único/bulk-fill) e da técnica restauradora (aplicação ou não de líquido modelador entre camadas de resina composta e utilização ou não de pinos de fibra de vidro para aumentar a retenção do material restaurador) no desempenho físico-mecânico de restaurações do tipo endocrown. O trabalho foi dividido em quatro estudos: (1) uma revisão sistemática e meta-análise da literatura com o objetivo de averiguar se a posição dentária e o tipo da técnica restauradora (endocrown ou com pino de fibra de vidro) influenciariam na resistência à fratura das restaurações; (2 e 3) estudos in vitro que avaliaram se a presença de um material resinoso fluido (líquido modelador) entre as camadas de resina composta melhorariam o desempenho físico-mecânico e estabilidade de cor/translucidez de restaurações de resina composta; e (4) um estudo in vitro que determinou a resistência à fadiga e à fratura de restaurações endocrown, avaliandose a influência do tipo da técnica restauradora (direta ou indireta) e dos sistemas restauradores utilizados. O primeiro estudo foi descrito de acordo com o PRISMA buscando responder se há diferença na resistência à fratura de dentes restaurados com endocrown e pino de fibra de vidro. O segundo e terceiro estudos envolveram metodologias de caracterização físico-mecânica e ópticas dos grupos experimentais. Já o quarto estudo simulou o desempenho de restaurações endocrown em cerâmica, resina composta de preenchimento único ou convencional, contendo ou não líquido modelador; ainda, as restaurações foram confeccionadas usando-se técnica direta ou indireta, e posteriormente submetidas à fadiga mecânica. Para análise estatística dos dados quantitativos, foi utilizado um nível de significância de 5%. Os resultados da meta-análise mostraram que as endocrowns apresentaram resistência à fratura semelhante as restaurações com resina composta. Os resultados dos estudos in vitro indicaram que o líquido modelador (resina adesiva) entre as camadas de resina composta melhorou o desempenho físico-mecânico do material quando comparado à não utilização, sendo mais evidente quando utilizado o adesivo hidrófobo. Com a conclusão deste trabalho, constatou-se que restaurações endocrown podem ser favoravelmente utilizados na rotina clínica para restabelecer a função e estética de dentes tratados endodonticamente e que apresentem grande destruição coronária. Ainda, foi possível compreender o comportamento físico e mecânico de resinas compostas modelados com resinas adesivas (líquido modelador), contribuindo asism para a seleção do melhor sistema restaurador e técnica restauradora para a confecção de restaurações do tipo endocrown

Which materials would account for a better mechanical behavior for direct endocrown restorations?

Purpose: To investigate the mechanical performance and fracture behavior of endocrown restorations prepared using different composite materials and following a direct technique. Methods: Sound molars were cut at 2 mm above the cementoenamel junction, endodontically treated, and allocated according to the type of restoration (n ¼ 7): without post (endocrowns) or with post (post-retained restorations). Endocrowns were fabricated with conventional composite (Filtek Z350); bulk fill composite (Filtek Bulk Fill); conventional composite modeled using resin adhesives (SBMP: Scotchbond Multipurpose Adhesive; or SBU: Scotchbond Universal Adhesive); and lithium disilicate ceramic (E.max; Positive control). The post-retained restorations were fabricated with glass- fiber post combined with conventional or bulk fill composites. All restorations were bonded following an etch-and-rise adhesive approach or self-adhesive resin cement. The teeth were submitted to fatigue (Byocycle) and compression (EMIC DL500) testing at a crosshead speed of 1 mm/min. Data were analyzed with ANOVA and Tukey (p < 0.05) and Weibull analysis was carried out in order to evaluate the reliability of restorations. Results: The bulk-fill-based endocrown showed a stronger performance than the control. The presence of SBMP or the use of bulk-fill composite resulted in the occurrence of less aggressive fractures than the other restorative systems. Endocrowns bonded directly to the tooth seemed to produce similar fracture strength properties as compared to endocrowns bonded using self-adhesive resin cementation. The bulk-fill-based endocrown showed the greatest reliability of study. Conclusion: Resin-based restorative materials seem to be interesting alternative options to fabricate large dental restorations in lieu of the more traditionally used glass ceramics or root canal post systems

Translucency and color stability of resin composite and dental adhesives as modeling liquids – A one-year evaluation

Abstract The aim of this study is to evaluate the influence of modeling liquids on the translucency and color shade of resin composites (RCs) after one year of storage. RC specimens were prepared using either a conventional insertion technique (control; without modeling liquid) or a restorative dental modeling insertion technique (RDMIT) with dental adhesives as modeling liquids (Scotchbond™ Multi-Purpose [SBMP; 3M ESPE] or Adper™ Single Bond 2 [SB; 3M ESPE]). The initial colors of the specimens were obtained with a digital spectrophotometer and the CIEL*a*b* color system, after which specimens were stored (37°C) in distilled water or red wine for 12 months. Color measurements were reassessed after 6 and 12 months of storage, and scanning electron microscopy was performed after 12 months. Translucency and color change (ΔE*) were calculated and analyzed using ANOVA and Tukey’s test (α = 5%). RC samples prepared via RDMIT showed a translucency similar to that of control samples. ΔE* was also less intense for RCs containing SBMP than for RCs containing SB. Specimens stored in wine showed a clear pattern of degradation, especially in the control group, and surface degradation seemed to be less intense for specimens prepared with SBMP and SB than for specimens without. Specimens stored in water did not show clear evidence of surface degradation. RDMIT appears to be an interesting approach to reduce ΔE* in RCs over time without negative effects on the translucency of the material. However, the modeling liquid should feature a hydrophobic composition, similar to that used in the SBMP group, the achieve the best results

Impairment of resin cement application on the bond strength of indirect composite restorations

The aims of this study were to evaluate the effect of immediate and delayed resin cement application on the microtensile bond strength of indirect composite resin restorations and, to evaluate adhesive strategies (for regular resin cement or humidity parameters for self-adhesive resin cement). Forty-five enamel/dentin discs (0.5 mm height and 10 mm of diameter) obtained from bovine teeth were divided into nine groups (n = 5). For regular cement, the variation factors were cementation technique at three levels (immediate cementation, 5 or 30 min after adhesive system application); and type of adhesive system at two levels (three- or two-step). For self-adhesive cement, the dentin moisture was the source of variation at three levels (normal, dry, or wet cementation). The specimens were submitted to microtensile bond strength (μTBS) testing using a universal testing machine. Data were analyzed by ANOVA, Tukey’s test, and linear regression. Regular cement and three-step etch-and-rinse adhesive system showed the highest values of bond strength (25.21 MPa–30 min of delay). Only for this condition, three-step adhesive showed higher bond strength than the two-step adhesive. Nevertheless, the linear regression showed that irrespective of the strategy, the use of the two-step approach when compared with three-step adhesive system decreased μTBS (p < 0.001). The failure analysis showed predominant adhesive failures for all tested groups. All groups had comparable values of bond strength to bovine dentin when the same materials were used, even in suboptimal clinical conditions

New material perspective for endocrown restorations: effects on mechanical performance and fracture behavior

Abstract The aim of this study was to investigate the mechanical performance and the fracture behavior of endocrown restorations prepared using distinct restorative materials. A total of 42 sound molars with similar crown size and shape were cut at 2 mm above the cementoenamel junction and endodontically treated. They were categorized according to the restorative material used to fabricate endocrown restorations (n=7), namely, conventional composite (Filtek™ Z350 XT), bulk fill composite (Filtek™ Bulk Fill), conventional composite modeled using resin adhesives (SBMP: Scotchbond™ Multipurpose Adhesive; or SBU: Scotchbond™ Universal Adhesive), and IPS e.max lithium disilicate (Ivoclar Vivadent; positive control). Unprepared sound teeth were used as negative control. All endocrowns were bonded using a self-adhesive cement (Rely-X™ U200). The teeth were submitted to fatigue (Byocycle) and fracture (EMIC DL500) testing. Load-to-fracture (in N) and work-of-fracture (Wf, in J/m2) values were analyzed by ANOVA (p 0.05). The endocrowns fabricated by combining Z350 and SBMP had the least harsh fractures, in contrast to endocrowns prepared using Z350 only, which exhibited an equilibrium between repairable and irrepairable fractures. The e.max endocrowns exhibited more aggressive failures (root fracture) than other groups, resulting in higher rates of irrepairable fractures. In conclusion, dental practitioners may satisfactorily restore severely damaged nonvital teeth using the endocrown technique. Composite endocrowns prepared using resin adhesive as modeler liquid or using bulk fill material may result in less aggressive failures, thus providing a new material perspective for endocrown restorations

Effects of modeling liquid/resin and polishing on the color change of resin composite

Abstract Modeling liquids/resins have been used to build up resin composite (RC) restorations, although there is a lack of information regarding their effects on the color stability of the latter. Therefore, the purpose of the present study was to evaluate the effects of the presence of modeling liquid between layers of RC and the finishing/polishing state of the material on color change in specimens exposed to red wine staining over time. Specimens were prepared by placing four increments (±0.5 mm thick) of RC (Filtek™ Z350 XT, 3M ESPE) into molds; half of which were prepared by applying modeling liquid (Scotchbond™ Multi-Purpose™ Adhesive, SBMP, 3M ESPE) between the layers of RC, whereas the other half were prepared without SBMP (control). Light-activation was performed after application of the final RC layer using a light-emitting diode (Radii, SDI) curing unit with an irradiance of 900 mW/cm2 for 20 s. Each group was divided according to the surface finishing protocol (n = 7): nothing (non-polished) or polishing with Sof-Lex™/diamond paste (polished). Initial colors of the specimens were evaluated with a digital spectrophotometer and the CIEL*a*b* color system. The specimens were stored in wine (37°C) for 12 months, and the color measurements were reassessed after 4, 6, and 12 months of storage. Scanning electron microscopy (SEM) analysis was performed at the end. Data were analyzed using ANOVA and Tukey’s test (α = 5%). The presence of SBMP resulted in lower overall color change of the RC as compared with the control. The non-polished specimens exhibited a significantly higher color change than the polished specimens. SEM images corroborated the previous findings. In summary, the use of modeling liquid between layers of RC shows potential for application to reduce or delay the staining process of RC over time. Moreover, polishing is essential to provide increased color stability of the RC restoration