Does radiotherapy compromise root canal sealer penetration? An in vitro confocal laser microscopy study

To evaluate the penetration of root canal sealers into dentinal tubules when radiotherapy (RT) is applied to the head and neck region.

Ninety-six mandibular single-rooted premolars were randomly divided into two groups (n = 48). One group was not irradiated; the other was exposed to radiation 60 Gy (2 Gy/day, 5 days/week for 6 weeks). The root canals were prepared, and four subgroups were created based on the sealer used (n = 12): AH Plus (AHP), AH Plus Bio (AHPB), Bio-C Sealer (BC), and GuttaFlow Bioseal (GFB). One-millimeter-thick dentin slices were obtained from coronal, middle, and apical regions. Maximum penetration depth (MPD), penetration percentage (PP), and area (PA) values were evaluated using a confocal laser scanning microscope. Statistical analyses were performed using one-way ANOVA, Tukey HSD, and independent t-tests, with a significance level of α = 0.05.

Radiotherapy significantly increased the sealer PP in the middle-third of the AHP (p = 0.048) and AHPB (p = 0.022) groups, as well as in the apical-third (p = 0.028) of the GFB group. BC was not affected (p > 0.05). In all groups, penetration values increased from the apical toward the coronal-third. Among irradiated groups, the GFBRT showed higher PP (p = 0,037) in the apical and higher MPD (0,014) in the middle-third compared to BCRT CONCLUSION: Radiotherapy alters the dentinal penetration of sealers depending on material and root region.

The present findings contribute to the understanding of sealer penetration under simulated radiotherapy conditions and may serve as a basis for further clinical research.