effect of intracanal glass-ionomer barrier thickness on microleakage in coronal part of root in endodontically treated teeth: an in vitro study

Statement of the problem: the most common cause of endodontic treatment failures is improper coronal sealing. therefore, besides to proper root sealing, coronal sealing which is supported by a proper restoration has a major role in endodontic treatment success, and coronal microleakage should be considered as an etiologic factor in endodontic treatment failure. glassionomer (gi) has been proposed as a coronal barrier for microleakage after endodontic treatment. purpose: this study aimed to evaluate the coronal microleakage in giobturated root canals in endodontically treated teeth using different thicknesses of gi. materials and method: in this invitro study, fortyfive singlerooted extracted human teeth with single canals were collected and disinfected with 0.5% chloramine solution. after endodontic treatment, teeth were divided into 3 groups. in the group 1 to 3, 1 to 3 mm of guttapercha was removed and gi was replaced at 1, 2 and 3mm thicknesses respectively. then subgroups were placed in methylene blue dye and the microleakage was assessed using dye penetration. results: the mean dye penetration in groups 1, 2 and 3 were 5.1, 3.7 and 2.9, respectively, with statistically significant differences. group 1 exhibited the highest amount of dye penetration while group 3 showed the least one. moreover, a significant difference between groups 1 and 2 (p = 0.002) and a nonsignificant difference between groups 2 and 3 (p = 0.098) was detected in mean dye penetration. conclusion:  thicker layers of gi might decrease the coronal microleakage. gi at 3mm thickness resulted in the best protective effect on coronal microleakage in endodontically treated teeth, though further studies are needed to confirm these results.