Examination of the Effect of Preheating Process on Microtensile Bond Strength in the Cementation of Indirect Restorations The Effect of Preheating Process on Microtensile Bond Strength

Abstract

Aim: The aim of this study was to investigate the effect of preheating of inlay and onlay restorations prepared from composite materials and using a CAD/CAM device on microtensile bond strength in different structures.

Methodology: In this study, 90 impacted human third molar teeth unaffected by the mouth environment were used. These teeth were divided into 3 groups. MOD inlay cavity preparation was performed on all samples according to the parameters specified. For the first group, restorations were prepared using a CAD/CAM device. For the second group, a fiber-reinforced composite (EverX Posterior, GC, Tokyo, Japan) was used on the bottom of the cavity to simulate dentin structure. Restoration was then completed using the laboratory composite system (Gradia, GC, Tokyo, Japan). For the third group, restorations were completed using the laboratory composite system (Gradia, GC, Tokyo, Japan) alone. Er,Cr:YSGG laser (Fotona Laser AT Fidelis Plus III, Slovenia) was administered on all prepared restorations for surface roughening. In the cementation of the restorations, resin cement was administered with and without preheating. The prepared samples were placed in a microtensile tester, and the sticks were broken off by setting the loading speed at 1 mm/min. The prepared samples were tested for microtensile bond strength (Microtensile Tester, Bisco, Schaumburg, IL, USA). The results obtained in Newtons were divided into the surface area and converted to MPa. The results were recorded as microtensile bond strength values.

Results: There was no statistically significant difference between the groups in terms of the statistical evaluation of the microtensile bond strengths of the samples in which the adhesive cement was pre-heated (P) and not pre-heated (N) during the cementations (p>0.05). There was a statistically significant difference (p<0.05) in terms of the microtensile bond strength values between the groups in which the adhesive cement was pre-heated during the cementation of restorations.

Conclusion: It was observed that exposure of the adhesive cement to preheating in the cementation of the EverX Posterior-based inlays adversely affects the bond strength. It was observed that the preheating process statistically significantly increased the bond strength in the inlays made using the Gradia composite. Preheating of the cement in the cementation of Cerasmart composite inlays produced using the CAD/CAM system did not affect the microtensile bond strength.