Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Abstract

Objective:This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations.Material and Methods:Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05).Results:The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition.Conclusions:The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Five second photoactivation? A microhardness and marginal adaptation in vitro study in composite resin restorations

“…Analysis of the highest gap width has been successfully presented by other authors for the assessment of marginal adaptation, and as the highest gap width has a strong relationship with contraction stress, it can be used to assess polymerization shrinkage and its effects. Values for the highest gap width in the resin being studied did not differ significantly between the continuous and PLS – 5 second groups.…”

“…Hardness tests and marginal adaptation observations are appropriate methods for analysing these variables. Marginal adaptation can be assessed using scanning electron microscopy, and an epoxy‐resin replica is used in this type of analysis to avoid possible artefacts generated during preparation for microscopy, such as cracks in the tooth as a result of the dehydration process. The hardness of a material is a property often used to measure its degree of conversion indirectly, and for the same material, higher hardness values correspond to higher levels of conversion.…”

Interfacial microscopic examination and chemical analysis of resin-dentin interface of self-adhering flowable resin composite

“…Most of the clinical studies assessing the performance of an adhesive system use class V cavities 8 . EDX analysis permits identification of silver particles, thus giving an indication about the chemical analysis of the interface 9 .…”

Efectos sobre microdureza y grado de conversión de dos tipos de resinas sometidas a tratamientos de pospolimerización

“…Desde la aparición de las resinas compuestas (1960) [1], los avances han sido muchos con respecto a su composición y utilización; sin embargo, las restauraciones de resinas compuestas presentan deficiencias en el sellado marginal como consecuencia de la contracción de polimerización [2]. Para compensar estos inconvenientes, los sistemas de resinas compuestas indirectas representan la mejor alternativa.…”