ER:YAG Laser Application in Debonding of Two Ceramic Materials Using Two Types of Resin Cements

Abstract

This in-vitro study was designed to evaluate the efficiency of Er:YAG laser in the debonding of two glass ceramic materials; lithium disilicate (IPS e.max CAD) and zirconia reinforced lithium silicate (VITA SUPRINITY) using two types of resin cements; light cured resin cement and dual cured resin cement. Fifty-six freshly extracted maxillary premolars were collected, examined and those with cracks or structural defects were discarded. The premolars were stored in saline during the study. The extracted teeth were embedded in acrylic resin blocks for fixation. The fifty-six samples (n=56) were randomly divided into two main groups according to the type of glass ceramic material used (n=28) ; group (E) :lithium disilicate (IPS e.max CAD) and group (S) : zirconia reinforced lithium silicate (VITA SUPRINITY). Using IsometTM 4000, IPS e.max CAD and VITA SUPRINITY specimens were sectioned with dimensions 4x4 mm and thickness 0.5 mm. Dimensions and thickness of ceramic specimens were confirmed after sectioning by Digital caliper. Veneer samples were crystallized and glazed using the designated compatible glaze. Buccal surfaces of extracted teeth were prepared to receive veneers. Surface treatment was performed for bonding surfaces of the veneer and tooth. Ceramic veneers of both groups were etched using 9.5% hydrofluoric acid for 20 seconds to roughen the surface and increase surface area for bonding then rinsed thoroughly with water and dried followed by application of silane coupling agent for one minute.