Effect of resin liners on the microleakage of class V dental composite restorations Efeito do uso de forradores resinosos sobre a microinfiltração de restaurações classe V em compósito odontológico

PURPOSE: The aim of this study was to evaluate the effect of an adhesive applied in layers of different thickness or in association with a filled adhesive or with a low viscosity composite liner on the microleakage of composite restorations. METHODS: Forty bovine incisors were prepared with round cavities (4mm diameter X 2mm depth) on the cementoenamel junction. The teeth were assigned to four groups according to the liner used: 1 (control) - application of 1 layer of the Scotchbond Multi Purpose adhesive system (SBMP); 2 - application of 3 layers of SBMP; 3 - application of 1 layer of SBMP followed by application of one layer of Optibond FL adhesive; 4 - application of one layer of SBMP followed by application of flowable composite Flow-it. All cavities were restored using composite resin Z100. The microleakage test was conducted according to ISO (TR11405). Data were analyzed by Kruskall-Wallis test (a=0.05). RESULTS: Group 4 showed less leakage than Group 1. Groups 2 and 3 showed intermediate values and there were no statistical differences when they were compared to the values of Groups 1 and 4 CONCLUSION: The use of resin liners with flowable composites can reduce the microleakage of composite restorations.<br>OBJETIVO: O objetivo desse estudo foi avaliar os efeitos da aplicação de um adesivo em diferentes espessuras ou em associação com um adesivo com carga ou com compósito de baixa viscosidade na microinfiltração marginal de restaurações com compósito odontológico. MÉTODOS: Quarenta incisivos bovinos foram selecionados e cavidades circulares (4mm de diâmetro X 2mm de profundidade) foram preparadas na região da junção cemento-esmalte. Os dentes foram então divididos em quatro grupos de acordo com o forramento utilizado: 1: (controle) aplicação do sistema de união Scotchbond Multi Uso (SBMU) - 1 camada de adesivo; 2: aplicação de 3 camadas do adesivo SBMU; 3: aplicação do SBMU, seguido pela aplicação de uma camada do adesivo Optibond FL; 4: aplicação do SBMU seguido pela aplicação de forramento com o compósito de baixa viscosidade Flow-it. Todas as cavidades foram restauradas com o compósito Z100. O teste de microinfiltração foi conduzido de acordo com a ISO (TR11405). Os dados foram analisados pelo teste de Kruskall-Wallis (p>0,05). RESULTADOS: O grupo 4 apresentou redução significativa dos níveis de infiltração quando comparado ao grupo 1. Os grupos 2 e 3 apresentaram valores intermediários e não foram detectadas diferenças significativas quando estes grupos foram comparados aos grupos 1 e 4. CONCLUSÃO: O uso de forramento com compósito de baixa viscosidade pode reduzir os níveis de infiltração marginal, possibilitando melhora na qualidade das restaurações em compósito odontológico

Physicomechanical evaluation of low-shrinkage dental nanocomposites based on silsesquioxane cores

10.1111/j.1600-0722.2007.00449.xEuropean Journal of Oral Sciences1153230-23

The effect of fibre insertion on fracture resistance of root filled molar teeth with MOD preparations restored with composite

Erdemir, Ali/0000-0003-1140-3887WOS: 000226528900001PubMed: 15667628Aim To evaluate the effect of using flowable composite with or without leno woven ultra high modulus polyethylene fibre reinforcement on fracture resistance of root filled mandibular molars with mesio-occluso-distal (MOD) preparations. Methodology Sixty sound extracted human mandibular molars were randomly assigned to five groups (n = 12). Group 1 did not receive any preparation. From groups 2 to 5, the teeth were root filled and MOD preparations were created. Group 2 remained unrestored. Group 3 was restored with a dentine bonding system (DBS; SE Bond, Kuraray, Japan) and composite resin (CR) (AP-X; Kuraray). In group 4, flowable composite resin (Protect Liner F; Kuraray) was used before restoring teeth with CR. In group 5, leno woven ultra high modulus polyethylene ribbon fibre (Ribbond, Seattle, WA, USA) was inserted into the cavities in a buccal to lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens were stored in 100% humidity at 37 degreesC for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min(-1). The mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (anova) and Tukey post-hoc test. Results The mean load necessary to fracture the samples in each group were (in N): group 1: 1676.75 +/-154.63(a), group 2: 376.51 +/- 37.36(b), group 3: 733.23 +/- 133.33(c), group 4: 786.48 +/- 145.34(c), group 5: 943.63 +/- 121.15(d). There were statistically significant differences between the groups annotated with different letters. Conclusions (i) Use of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molar teeth with MOD preparations, (ii) use of polyethylene ribbon fibre under composite restorations in root filled teeth with MOD preparations significantly increased fracture strength