Two-year effects of chlorhexidinecontaining adhesives on the in vitro durability of resin-dentin interfaces and modeling of drug release

Objectives: To evaluate the effects of addition of diacetate chlorhexidine (CHX) at different concentrations into two etch-And-rinse adhesive systems on CHX release, as well as the immediate (IM) and two-year (2-Y) resin-dentin microtensile bond strength (lTBS) and nanoleakage (NL). Methods: CHX was added to XP Bond (XP) and Ambar (AM) at concentrations of 0.0 wt% (control); 0.01 wt%; 0.05 wt%; and 0.1 to 0.2 Pamela Malaquias, DDS, Ms, PhD candidate, Department of wt%. To assess the cumulative CHX release, adhesive disks were made in a metallic matrix and after light-curing were stored in water. Ultraviolet spectrophotometric measurements of the storage solution were performed to examine the release kinetics of CHX. For lTBS and NL, the occlusal enamel of molars was removed and the adhesives were applied to the dentin surface after acid etching. After composite resin build-up, specimens were sectioned to obtain lTBS sticks. The specimens were subjected to lTBS and NL at IM and after 2-Y. In addition, specimens underwent examination for CHX using micro-Raman spectroscopy. All data were submitted to statistical analysis (a=0.05). Results: With regard to CHX release, AM showed a slower and gradual release of CHX while XP released CHX more quickly (p,0.05), and CHX was still present in the hybrid layers after 2-Y. Both adhesives showed CHX release at 2-Y water storage. Both CHX-containing adhesives showed higher lTBS values than did the control group (p,0.05). adhesive disks were made in a metallic matrix and after light-curing were stored in water. Ultraviolet spectrophotometric measurements of the storage solution were performed to examine the release kinetics of CHX. For lTBS and NL, the occlusal enamel of molars was removed and the adhesives were applied to the dentin surface after acid etching. After composite resin build-up, specimens were sectioned to obtain lTBS sticks. The specimens were subjected to lTBS and NL at IM and after 2-Y. In addition, specimens underwent examination for CHX using micro-Raman spectroscopy. All data were submitted to statistical analysis (a=0.05). Results: With regard to CHX release, AM showed a slower and gradual release of CHX while XP released CHX more quickly (p,0.05), and CHX was still present in the hybrid layers after 2-Y. Both adhesives showed CHX release at 2-Y water storage. Both CHX-containing adhesives showed higher lTBS values than did the control group (p,0.05).