Clinical observation of two different resin cements on lithium disilicate glass-ceramic veneer

Objective: To assess the bonding effect of two resin cement on lithium disilicate glass ceramic veneer.Method: The study was conducted at the Medical School of Nanjing University, Nanjing Stomatological Hospital, China, in2023, and comprised isolated teeth that were prepared at the occlusal surface of premolars using high-speed emery needleunder running water, and then divided into groups A, B, C, D and E with the enamel area ratio being 0%, 25%, 50%, 75%and 100%, respectively. Each group was divided into subgroups 1 and 2. Groups A1, B1, C1, D1 and E1 were bonded byRelyX U200 bonding system, while groups A2, B2, C2, D2 and E2 were bonded using the Variolink Veneer bonding system.Followed by 24h of constant water bath, all the bonded specimens were placed in a universal dynamometer for shearstrength test. The bond fracture interface was observed under stereopicroscope. Data was analysed using SPSS 22.Results: Of the 100 specimens, 20(20%) were in each of the 5 groups. The shear strength of Variolink Veneer group onlithium disilicate glass ceramic veneer was higher relative to the RelyX U200 group (p<0.05). The shear strength betweenisolated teeth in group A1 and lithium disilicate glass ceramic veneer was the weakest, while the shear strength betweenisolated teeth in group E1 and lithium disilicate glass ceramic veneer was the strongest. With the increase of the enamelarea ratio, the shear strength between isolated teeth and lithium disilicate glass ceramic veneer was enhanced (p<0.05).There were 21 failures; 9(43%) interface and 12(57%) mixed.Conclusion: The bonding strength of Variolink Veneer was higher than RelyX U200.Keywords: Disilicate glass ceramic veneer, Variolink Veneer, RelyX U200, Bonding strength.