EFFECT OF DIFFERENT IRRIGATING PROTOCOLS ON THE BOND STRENGTH OF THE ACTIV GUTTA PERCHA ROOT CANAL OBTURATION SYSTEM (COMPARATIVE IN VITRO STUDY)

Abstract

INTRODUCTION: Different irrigations may cause alteration in the composition of dentin, thereby affecting the adhesion of materials to dentin surfaces. OBJECTIVES: evaluate the effect of different irrigating protocols used as final rinse on the bond strength of the ActiV gutta percha. MATERIALS AND METHODS: Forty extracted single rooted lower premolars were used. Teeth were decoronated to standardize the root length to 15mm. The canals were instrumented using OneShape rotary system. Teeth were irrigated with 2.5% sodium hypochlorite then divided into four parallel groups according to the final rinse (n=10). GroupI: 10ml 17% Ethylene diaminetetraacetic acid, followed by 10ml of 2.5% NaOCL; GroupII: 10ml of 1.3%mixture of a tetracycline isomer, an acid and detergent (MTAD); GroupIII: 10ml of 2% chlorhexidine gluconate; GroupIV: 10ml 2.5% NaOCL(control). All the root canals were filled using ActiV GP. Slicing was done at the coronal and middle thirds for push-out test to measure bond strength. Then failure mode was evaluated under stereomicroscope. Data were analysed using t-test and one-way ANOVA test. RESULTS: Group III yielded significantly the highest mean push-out bond strength (2.91± 0.79 MPa), followed by group II (2.39± 0.89 MPa), then group IV (1.80± 0.61MPa) and finally group I (1.61± 0.52 MPa). The bond strength values of the middle sections were significantly higher than that of the coronal sections. The failure mode was predominantly cohesive in groups II and III and adhesive in groups I and IV. CONCLUSIONS: CHX and MTAD increased the bond strength of ActiV GP, while EDTA decreased the bond strength. The push out bond strength values were affected by the location of root segment. There was correlation between the push out bond strength values and the failure mode.