RESUMEN
The current in vivo study evaluated the degradation of dentin hybrid layers in deep occlusal-surface resin composite restorations using TEM. Caries-free premolars scheduled for extraction as part of orthodontic treatment were prepared and restored, then extracted after 12 months. The adhesive used was a single-bottle etch-and-rinse acetone-based product (Prime & Bond NT, Dentsply/Caulk). Control group restorations (n=8) were placed according to the manufacturer's instructions, while the experimental group received application of a 2% solution of chlorhexidine digluconate after etching and rinsing and prior to application of the adhesive. Extensive degradation was observed in all of the teeth in the control group after 12 months, while no degradation was observed in the experimental group. In vitro testing showed no significant difference in immediate microtensile bond strength between the control and experimental adhesive protocols.