Effect of different root canal sealers on apical patency regaining and instrument surface deformation during retreatment: A scanning electron microscopy evaluation

The aim of the present study was to evaluate surface deformation and the reestablishment of apical patency following the retreatment of root canals obturated with sealers of different chemical compositions using scanning electron microscopy (SEM). Twenty-four extracted maxillary central incisors were shaped, cleaned, and randomly allocated into three groups ( n = 8) according to the sealer used: resin-based AH Plus Jet, calcium silicate-based Bio-C Sealer, and MTA-based MTA Bioseal. Following retreatment procedures, the time required to reestablish apical patency was recorded. The rotary files were then examined under SEM at various magnifications to assess surface deformation. Statistical analysis comprised the Shapiro–Wilk test for normality, one-way ANOVA for quantitative comparisons, the chi-square test for categorical variables, and the Levene test for homogeneity of variances. Ordinal SEM deformation scores were analyzed using the linear-by-linear association test (α = 0.05). The time required to reestablish apical patency was significantly longer in the AH Plus Jet group compared to the MTA Bioseal group ( p < 0.05), whereas no significant differences were observed among the other comparisons ( p > 0.05). SEM analysis demonstrated higher surface deformation scores in files used with AH Plus Jet, moderate scores with Bio-C Sealer, and lower scores with MTA Bioseal. The findings indicate that sealers with different chemical compositions may affect the time for regaining apical patency and the severity of surface deformation, and that these sealer-related factors may substantially influence the fracture risk of rotary files.