Evaluation of Marginal Integrity and Internal Gap Formation in Fiber-Reinforced Restorations

Abstract

The aim of the present study was to evaluate marginal integrity and gap formation in fiber-reinforced restorations, as well as to analyze whether the nature of the fibers influences these conditions, through an in vitro study. Cavities were prepared in thirty sound bovine incisors, previously immersed in a 1% chloramine solution, washed, and stored under refrigeration in distilled water. The buccal surfaces of the teeth were flattened using a polishing machine with silicon carbide papers. Subsequently, Class I cavities (∅ = 5.0 mm; h = 4.0 mm) were prepared using a cylindrical diamond bur (#4054). The teeth were then restored and randomly assigned to six experimental groups (n = 5): G1 – Bulk Fill One; G2 – Z250 resin; G3 – Ribbond + Bulk Fill One; G4 – Ribbond + Z250; G5 – Interlig + Bulk Fill One; and G6 – Interlig + Z250. After restoration, the specimens were stored in an incubator at 37 °C. The percentage of marginal gap (%MG) at the tooth–restoration interface was evaluated using three-dimensional laser scanning confocal microscopy (3D-LCM). In addition, internal gap formation was analyzed using micro-computed tomography (micro-CT). The data were analyzed using statistical models appropriate to the observed distributions (α = 0.05). The results showed that group G5 presented the highest %MG values, while no statistically significant differences were observed among the groups regarding internal gap formation. It can be concluded that fiber insertion influences the percentage of marginal gaps but does not affect internal gap formation.

Keywords: Resin composite, marginal gap , internal fit