Immediate Pre-Endodontic Dentin Sealing (IPDS) Improves Resin-Dentin Bond Strength

Objective: Chemicals used during canal disinfection and endodontic sealers have a deleterious effect on dentin bond strength. The aim of this study was to evaluate a novel clinical sequence to improve the resin–dentin microtensile bond strength (μTBS) to endodontically treated teeth.

Materials and Methods: Twenty human molars were distributed in four experimental groups (n = 5, N = 20): C—control group without exposure to any endodontic chemical substances (2.5% sodium hypochlorite, 17% EDTA and endodontic cement); LDh—late dentin hybridization (Dh) with Dh at the time of final restoration, after exposure to chemical substances; IPDS—immediate pre-endodontic dentin sealing, with Dh before exposure to chemical substances; and PLDh—late Dh after exposure to chemical substances and after dentin repreparation with ultrasonic diamond tip. Teeth were restored with resin composite and the microtensile test was performed after 24 h.

Results: The highest bond strength values were found in the PLDh, IPDS, and C groups, without statistically significant differences among them. The lowest value was found in the LDh group. The LDh group presented a decrease of 70% when compared with the control group.

Conclusion: The resin–dentin microtensile bond strength was significantly improved by dentin hybridization before exposure to chemicals used during endodontics. Otherwise, substantial dentin repreparation is necessary to restore the bond strength after this exposure.

Clinical Significance: Early dentin hybridization (IPDS) before endodontic treatment not only improves the microtensile bond strength to dentin but also omitting this procedure would require significant repreparation of the exposed dentin after endodontic treatment to restore the bond strength. Hence, it allows the preservation of healthy tooth structure (no need for repreparation), as well as the reinforcement of weakened cusps and improvement of isolation (if combined with deep margin elevation, when necessary).