Evaluation of the effect of 2 different bonding systems and 2 different tooth conditioning on the bond strength of lithium disilicate veneers on enamel, dentin and enamel-dentin complex. In vitro and in vivo study.

Description :

2 In vitro studies: A total of 180 human extracted central incisors will be used for study 1 and 2. in study 1, 90 teeth will be used for studying the bonding strength of lithium disilicate veneers. they will be divided into 3 main groups(n=30). Group E1: Teeth are prepared in enamel. Group (ED1): Teeth are prepared in enamel in the incisal and middle third, and in dentin in the cervical third. Group D1: Dentin exposure on the entire tooth surface. Then the 3 groups will be subdivided into 6 subgroups (n=15) based on the bonding system received. Study 2: 90 teeth will be used for studying the bonding strength of lithium disilicate veneers after tooth conditioning with erbium-doped yttrium aluminum laser. Group E1: Teeth are prepared in enamel. Group (ED1): Teeth are prepared in enamel in the incisal and middle third, and in dentin in the cervical third. Group D1: Dentin exposure on the entire tooth surface. Then the 3 groups will be subdivided into 6 subgroups (n=15) based on the bonding system received. In vivo study: A total of 120 lithium disilicate veneers will be used to evaluate the success rate in vivo: absence/presence of fracture, debonding or marginal discoloration. The 120 veneers will be distributed into 15 patients receiving 6 anterior veneers for esthetic purposes (from right to left upper canine). These 120 restorations will be divided in 2 groups of 60 each, based on the bonding system used on the restorations.