Biomechanical effects of a hard insert and air space in mouthguards on the shock absorption and protection against fractures of direct resin composite veneers from trauma.

Background/aim: Mouthguards (MTG) are used to prevent dental trauma. However, their protective effect on esthetic restorations and whether modified MTGs are beneficial is uncertain. The aim of this study was to evaluate the effect of hard inserts and air spaces in MTGs in protecting direct resin composite veneers during impact.

Effect of exposure time and moving the curing light on the degree of conversion and Knoop microhardness of light-cured resin cements.

Objective: To evaluate the effect of exposure time and moving the light-curing unit (LCU) on the degree of conversion (DC) and Knoop microhardness (KH) of two resin cements that were light-cured through ceramic.

Methods: Two resin cements: AllCem Veneer APS (FGM) and Variolink Esthetic LC (Ivoclar Vivadent) were placed into a 0.3 mm thick matrix in 6 locations representing the canine to canine.