Effect of medical dressings on intracanal bond strength of BioRoot RCS root canal sealer

Objectives: To assess the effect of 5 different medical dressings on bond strength of BioRoot RCS sealer using a pull-out test.

Methods: Access cavities were prepared in 60 single-rooted teeth with straight root canals. The root canals were instrumented to ISO 60 with BioRaCe instruments (FKG Dentaire) and roots randomly assigned to 6 different experimental groups (n=10): (1) control (no medical dressing), (2) AH Temp (Dentsply DeTrey) (3) chlorhexidine gel 2% (GlaxoSmithKline), (4) ActivPoint (chlorhexidine point, Coltène Whaledent), (5) Calciumhydroxide Plus Point (Coltène Whaledent), (6) chlorhexidine gel/AH Temp paste. After removal of medical dressing experimental stainless steel spreaders of ISO 60 (sand-blasted with aluminum oxide and silica-coating, Komet Dental) were inspected for correct position and controlled by radiograph. After placement of BioRoot RCS sealer one spreader per canal was inserted. After 4 weeks of storage (37°C/100% humidity) bond strength was tested according to Ebert et al. (2011) using a Zwick universal testing machine (Zwick-Roell). Statistical analysis was computed using SPSS 23.0 (IBM).

Results: Bond strength values were not significantly different between the experimental groups (ANOVA, p=0.052). Median bond strength values were (group/bond strength [MPa]): (1) 3.85 MPa, (2) 4.21 MPa, (3) 4.49 MPa, (4) 3.76 MPa, (5) 2.97 MPa, (6) 2.99 MPa. Although there were no statistical differences found between the groups, the use of chlorhexidine gel and AH Temp resulted in the highest bond strength values within the present study.

Conclusions: Medical dressings did not significantly affect the bond strength of BioRoot RCS. However, the use of chlorhexidine gel or calcium hydroxide paste resulted in higher bond strength, respectively.