Sealing ability of materials applied to resected root surfaces: a micro-CT evaluation

ABSTRACT Aim: This study aimed to evaluate, using micro-computed tomography (microCT), the sealing ability of three different materials—Adhese Universal (AU), One-Fil Putty (OF), and Geristore (Ge)—when applied to the resected surface of the root apex following apicoectomy. Materials and Methods: Forty extracted permanent single-rooted teeth were prepared and filled using the single cone technique (SCT) with the bioceramic sealer One-Fil. Following a 3-mm apical resection, the samples were randomly divided into five groups. The positive control group (PCG) underwent retrograde filling with mineral trioxide aggregate (MTA), while the negative control group (NCG) received no additional treatment. In the three experimental groups, a superficial sealing material (SSM) was applied to the resected root surface: Adhese Universal (AU), Geristore (Ge), or One-Fil Putty (OF). Each sample was scanned with microCT at three timepoints: t0 (after orthograde canal obturation), t1 (after apical resection and group allocation), and t2 (after 24-hour immersion in 50% silver nitrate solution). For each scan, the following were evaluated: the total volume of voids (VoV) within the entire endodontic space, in the apical 3-mm and 1-mm segments, and within the SSM material; and silver nitrate infiltration into both the root canal space and the sealing material. Image analysis was performed using Amira software, and non-parametric statistical tests were applied (significance level set at p < .05). Results: Statistically significant differences were observed among the groups in both total VoV at t1 and nitrate infiltration at t2. The PCG exhibited the highest values for both parameters (p < .05). In contrast, SSM and NCG groups showed significantly lower VoV. Among the experimental groups, AU demonstrated the lowest levels of nitrate infiltration, both within the endodontic space and the sealing material itself, indicating superior sealing performance. Conclusions: The application of surface sealing materials to the resected apex appears to reduce apical leakage and void formation more effectively than retrograde filling. Among the materials tested, AU showed superior performance in terms of sealing ability and handling, despite some limitations in radiopacity and biocompatibility. Clinical Implications: Surface-applied sealing materials may offer a simpler and safer alternative to retrograde fillings in apical surgery. These findings could assist clinicians in selecting more effective materials and techniques for endodontic retreatments. Further research is needed to explore alternative materials and confirm the reproducibility of these results, potentially streamlining surgical procedures and improving patient outcomes.