The recovery effect of dentin biomodifiers on microtensile bond strength and sealer-penetration depth of coronal and radicular dentin: an <i>in vitro</i> experimental study

Objectives: This study aimed to assess the outcomes of bromelain enzyme and chlorhexidine (CHX) following endodontic irrigation by evaluating coronal dentin microtensile bond strength (μTBS) and radicular dentin sealer penetration depth. Methods: Fifty-one human molars with flat mid-dentin surfaces were soaked in sodium hypochlorite, then randomly assigned to three groups relying on the biomodification approach (n = 17): group 1, saline; group 2, 8% bromelain; and group 3, 2% CHX. After bonding and resin composite build-ups, the μTBS, failure mode, and bond interface were evaluated. Forty-two root canals of human molars were mechanically prepared and randomly distributed among three groups (n = 14), similar to the coronal-dentin biomodification protocol. The sealer-penetration depth was measured utilizing the scanning electron microscope. One- and two-way analyses of variance and the pairwise t- and chi-square tests were utilized. Results: The bromelain group showed the highest statistically significant resin-dentin μTBS values, followed by the CHX and control groups. For sealer-penetration assessment, the bromelain group showed the highest penetration at the middle and apical root levels, whereas CHX demonstrated the highest penetration at the coronal level. Conclusions: Bromelain biomodification positively influenced the resin-dentin bond strength and the sealer-penetration depth in apical and middle levels.