Effect of thickness on fluorescence of resin-composites and dental substrates

Objective: This study evaluated the effect of thickness on fluorescence of resin composites and tooth substrates (enamel and dentin). Material and methods: Ninety bovine incisors were used, resulting in 45 dentin and 45 enamel disks (6 mm diameter and 0.5, 1 , or 1.5 mm in thickness). Ninety discs of Charisma, Filtek Z350 and IPS Empress Direct (for enamel and dentin) resins at same dimensions were built . Fluorescence measurements were performed using a fluorescence spectrophotometer (RF-5301PC, Shimadzu Corp) with excitation at 365 nm. Data were submitted to 2-way ANOVA and Tukey’s post hoc tests (α = 0.05). Results : The 2 - way - ANOVA revealed statistically significant differences for all factors, as well as the interaction between them (p <0.05). Dentin specimens (1.5 mm) showed highest fluorescence (128.33 A.U.), while Filtek Z350 (dentin - 1.0 mm) showed the lowest fluorescence (29.84 A.U.). Thickness influenced fluorescence values of enamel substrate. Conclusion: The thickness influenced fluorescence of enamel and all resin composite assessed showed fluorescence lower than natural dentin. Keywords Dental enamel; Dental resins; Dentin; Spectrometry, Fluorescence.