Aim: to evaluate the cavity wall adaptation of nanofilled resin composite cured with different LED light intensities and with different thickness of buccal wall after thermocycling using environmental scanning electron microscope.
Materials and methods: the materials used for this study was nanofilled resin composite material (Filtex Z350XT, 3M, ESPE) shade A3with its corresponding bonding system (single bond universal, 3M, ESPE). A total of 10 sound extracted human maxillary premolar teeth were used in this study. The teeth were divided into 2 main groups of 5 teeth each according to curing light intensities; either standard LED curing mode (800 mW/cm2) for 30 sec or high intensity LED curing mode (1400 mW/cm2) for 10 sec. In each tooth, 2 cavity preparations were performed; moderate cavity preparation width (1/3 intercuspal distance) in the mesial aspect of each tooth and wide cavity preparation (1/2 intercuspal distance) in the distal aspect. All specimens were light cured using transtooth curing technique from the buccal and lingual surfaces. All specimens were subjected to thermocycling protocol. All specimens were subjected to the quantitative margin analysis, examined using environmental scanning electron microscope (ESEM). Two ways analysis of variance (ANOVA) test was used to study the interaction of both variables. The significance level was set at p < 0.05.
Results: Two ways ANOVA test revealed that the interaction of both variables was statistically significant (p=0.00). Comparing both intensities, a higher mean value was recorded in high intensity (6.57±1.29), with a significant difference (p=0.00). Comparing 1/2ICD and 1/3ICD, a higher mean value was recorded in 1/3ICD (6.52±2.19), with a significant difference (p=0.00).
Conclusions: The wall thickness greatly affects the cavity wall adaptation in transtooth curing technique.Applying High intensity irradiation technique compromise margin quality and marginal seal of resin composite restoration.