Effectiveness of cleaning protocols for temporary methacrylate-based resin cements in root canal dentin

Residual temporary cement may hinder fiber post bonding. Therefore, efficient root canal cleaning protocols are essential. This study investigated the effects of three cleaning methods on bond strength, adhesive interface quality as evaluated using scanning electron microscopy (SEM), and intratubular penetration of a self-adhesive resin cement as evaluated using confocal laser scanning microscopy (CLSM). Forty-two mandibular premolars were prepared using Reciproc R50, filled with AH Plus, and restored with provisional retainers cemented with Bifix Temp. Specimens were allocated to three groups (n = 14) according to the cleaning protocol: standardized drill (SD), drill with an ultrasonic insert (UI), or drill with a prophylactic brush (PB). Fiber posts were cemented using a self-adhesive resin cement. Push-out testing, failure mode analysis, and SEM/CLSM evaluations were performed. Bond strength (MPa) was analyzed using two-way ANOVA followed by Tukey's test, whereas failure patterns were analyzed using the chi-square test, and interface adaptation was analyzed using nonparametric tests. PB (4.42 ± 2.60 MPa) and UI (4.55 ± 2.41 MPa) showed significantly higher bond strength values and greater cement penetration than SD (3.04 ± 1.70 MPa) (p < 0.05). Mixed adhesive failures predominated, and SEM revealed no significant differences in interface adaptation. Cleaning with a PB or UI enhanced adhesive performance and resin cement penetration during fiberglass post cementation.