SEM Evaluation of the Hybrid Layer of Two Universal Adhesives on Sound and DI Type II Affected Dentin

Abstract

Universal nanofilled adhesives were recently introduced in restorative dentistry to simplify clinical procedures and improve adhesion in different clinical situation. This study investigated the effectiveness of two universal adhesives on both sound and dentinogenesis imperfecta type II (DI-II)-affected teeth. To evaluate the effectiveness of adhesion on both sound and DI-II-affected teeth, four samples, two sound extracted molars and two extracted molars affected by DI-II were selected. Coronal enamel and dentin were exposed, and the samples were used for testing two different universal adhesives, Universal Bond (Tokuyama) and All-Bond Universal (Bisco). After the adhesive procedures, the samples were stored in saline at room temperature for one week prior to SEM investigation for the interfacial bonding layer. The samples were longitudinally sectioned into two parts, obtaining two sections for the evaluation of the adhesive interface to the SEM. The SEM-morphology of the hybrid layer on the enamel was similar for the two universal adhesives tested. The study of the hybrid layer on sound dentin confirmed the great versatility of All-Bond Universal and Universal Bond adhesives in managing adhesion even on pathological dental substrates. Both universal adhesives tested showed encouraging results on DI-II-affected dentin, creating an effective hybrid layer even on the atubular and less mineralized altered dentin.