The Effect Of BioPure MTAD To Remove The Smear Layer And On The Apical Microleakage Of Obturated Canals

Successful root canal therapy depends on the method and quality of instrumentation, irrigation, disinfection and hermetic three-dimensional obturation of the root canal system. Numerous studies have shown that current methods of instrumenting root canals produce a smear layer that covers the shaped walls. Removal of the smear layer allows for intimate contact of medicals with dentinal tubules and increases the sealing ability of resin sealers. The purpose of this study in vitro was to evaluate the ability of BioPure MTAD to remove smear layer and the effect on apical sealing.Part I : Effect of Bioure MTAD to remove the smear layerObjective: The aim of this study was to evaluate and compare the ability of three different endodontic irrigants to remove smear layer in vitro.Methods: Forty extracted mandibular single-rooted human teeth were randomly divided into three test groups of each 10 and two control groups of each 5, all prepared by using a combination of Nickel-Titanium files and crown-down techniques. Sterile distilled water, 5.25% sodium hypochlorite or 1.3% sodium hypochlorite was used as endodontic irrigant during instrumenting. The canals were then treated with 5ml of one of the following solutions as final rinse respectively: sterile distilled water, 17% EDTA, 3% EDTA or BioPure MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope.Result: (1) The surfaces of samples in group A,C were covered with smear layer. The surfaces of root canals in the coronal and middle thirds of samples in group B, D, E were free of smear layer and statistical analysis confirmed no significant difference (p > 0.05) between them. (2) The apical third of canals in the group D were significantly cleaner (p<0.05) than in groups B and E; Comparison of the apical third of canals in the group B and E showed no significant differences (p>0.05). (3) Because the smear layer was not removed in groups A and C, the amount of erosion was not evaluated. The coronal and middle sections were significantly more eroded in group B than in group D and E (p<0.05). The degree of erosion of the coronal and middle sections of the canals in group D and E was not statistically different (p>0.05). (4) The degree of erosion in the apical section was not statistically different between group B, D and E (p>0.05).Conclusion: BioPure MTAD is an effective solution for removal of the smear layer on the surface of root canal. As an endodontic irrigant, it does not significantly change the structure of the surface of root canal. Part II : Evaluation of the effect of BioPure MTAD as an endodontic irrigant on the apical sealingObjective: The purpose of this study was to evaluate whether BioPure MTAD, used as a root canal irrigant, would affect the apical sealing ability of AH Plus sealer.Methods: Eighty-eight extracted mandibular single-rooted human teeth were randomly divided into two groups. Each group were randomly divided into four test groups of each 10 and two control groups of each 2, all prepared by using a combination of Nickel-Titanium files and crown-down techniques. Sterile distilled water, 5.25% sodium hypochlorite or 1.3% sodium hypochlorite was used as endodontic irrigant during instrumenting. The canals were then treated with 5ml of one of the following solutions as final rinse respectively: sterile distilled water, 1.3% sodium hypochlorite, 17% EDTA, 3% EDTA or BioPure MTAD. Obturation was accomplished using cold lateral condensation Technique(CLC) .The positive control group was obturated with gutta-percha without sealer. All test groups and the negative group was obturated with gutta-percha and AH Plus sealer. (1)Randomly choosing one of the two groups, the teeth were made transparent and dye penetration was measured by using a stereoscopic microscope. (2) Then microleakage was evaluated by dye extraction method. (3) In another group, the teeth were sectioned latitudinally and the amount of apical dye migration was measured by using a stereoscopic microscope. Result: (1) Evaluating the transparent teeth under the stereomicroscope, the mean distance of dying line for test groups were 1.81±0.73 mm, 0.53±0.49 mm, 0.40±0.44 mm, 0.39±0.55 mm respectively. Statistical analysis confirmed a significant difference (p< 0.05) between group C and other three test groups (D, E, F) and there were no significant difference (p>0.05) between group D, group E and group F. (2) The dye absorbance of group C was statistically higher (p< 0.05) than that of three other test groups, which were not different from each other (p>0.05). (3) Statistical analysis of microleakage at 0.50mm level confirmed no significant difference (p>0.05) between group C, group D, group E and group F. The section of group C showed more (p <0.05) dye leakage at level of 1.00mm, 1.50 mm and 2.00mm than other three test groups (D, E, F) and there were no significant difference (p>0.05) between group D, group E and group F at those levels.Conclusion: BioPure MTAD as a root canal irrigating solution did not adversely affect the apical sealing ability of AH plus sealer.