Abstract
Aim: The current research intended to assess the efficiency of mechanical and/or chemical cleaning methods (Ultrasonic and/or Acetone) of endodontic sealer remanent on the pulp chamber dentine and its outcome on the bond strength with composite restoration to the pulp chamber by the micro tensile bond strength (μ-TBS), and its failure modes by stereomicroscopy.
Method: 40 human permanent lower molars were selected to be used in this study. Every tooth has decoronated to 4 mm coronal to cementoenamel junction. The root canals were prepared via ProTaper Gold. ProTaper Gold obturators #F3 and AH Plus sealer were used for filling the canals. 2 mm apically of the occlusal gutta percha was removed to make a space for liner material. Glass ionomer restorative was used as liner material over the gutta percha to the level pulp chamber floor. The obturated teeth were then randomized divided into four identical test groups with 10 molars in every group. Group 1(Ultrasonic Cleaning) the sealer remnant was cleaned by Ultrasonic tip ET 20D, Group 2 (Acetone) the sealer remnant was cleaned by Acetone. Group 3 (Acetone / Ultrasonic) the sealer remnant was cleaned by both Acetone / Ultrasonic, and the Group 4 (Control) was not comminated with the sealer. All teeth were received Bulk Fill Restorative composite to fill the pulp chamber, the preparing the teeth for the μ-TBS test and determining the types of failure modes.
Results: Group 1 (Ultrasonic Cleaning) had the greatest reported μ-TBS (38.50 ± 7.91), while the least μ-TBS was reported in Group 2 (Acetone) 31.80 ± 7.42 with statistically significant different (p = 0.007).On other hand Group 1(Ultrasonic Cleaning), and Group 3 (Acetone / Ultrasonic) showed results similar to the results of Control Group with non-statistically significant different (P > 0.05). In concerning the distribution of failure mode, showed that the mixed-type failure mode (54%) was the most common one seen in Group 1 (Ultrasonic Cleaning), (51%) recorded in Group 4 (Control), (50%) recorded in Group 3 (Acetone / Ultrasonic), and the lowest was (39%) recorded in Group 2 (Acetone). While the distribution of adhesive failure mode was (45%) recorded in groups Group 2 (Acetone), (37%) recorded in Group 3 (Acetone / Ultrasonic), and (30%) recorded in both Group 1(Ultrasonic Cleaning) & Group 4 (Control).
Conclusion: Mechanical removal of resin sealer remanent by Ultrasonic Cleaning gives good condition for increasing the μ-TBS of composite restoration to the pulp chamber dentine of endodontically treated molars.