[Comparison of the sealing ability of three bioceramic root canal sealers using single-cone technique]

Objective: To analyze and compare the sealing ability of three bioceramic root canal sealers (iRoot SP, cRoot SP, nRoot SP) in root canal obturation using the single-cone technique by means of micro-CT. Methods: Single-rooted premolars freshly extracted from patients aged 14-24 years for orthodontic reasons at the Department of Oral and Maxillofacial Surgery, Shanghai Stomatological Hospital were collected. Thirty extracted teeth were strictly included according to the five inclusion criteria to ensure baseline consistency of the experiment and randomly divided into three groups (n=10) by lottery. The root canals were prepared using the ONE-PLEX single-file system. The three groups of extracted teeth were then obturated using the single-cone technique with iRoot SP, cRoot SP, and nRoot SP sealers, respectively. The obturated specimens were stored in a 100% humidity environment at 37 ℃ for 14 days to allow complete setting. Subsequently, the specimens were scanned using micro-CT. Three-dimensional reconstruction of the root canal system was performed using CTAn software. The void volume within the root canal was measured in the apical third (2-3 mm from the root apex), middle third (>3-5 mm from the root apex), and coronal third (>5-7 mm from the root apex), respectively. The root canal filling void percentage was calculated. Data regarding the total void percentage, interfacial gap percentage, and isolated void percentage in the apical, middle, and coronal thirds of the obturated specimens from the three groups were analyzed using analysis of variance or non-parametric tests with SPSS software. The significance level was set at P<0.05. Results: In the iRoot SP group, cRoot SP group, and nRoot SP group, the total void percentage after obturation showed no statistically significant differences in the apical segment [(16.81±3.15)%, (15.21±3.62)%, (13.52±2.90)%], the middle segment [(14.52±4.21)%, (12.66±2.37)%, (11.63±2.39)%], or the coronal segment [(11.96±5.31)%, (12.59±4.98)%, (10.09±1.77)%], respectively (P=0.093, P=0.129, P=0.417). No statistically significant differences were observed in the interfacial gap percentage among the groups in the apical segment, middle segment, or coronal segment after obturation (P=0.112, P=0.147, P=0.463). Similarly, no statistically significant differences were found in the isolated void percentage among the groups in the apical segment, middle segment, or coronal segment after obturation (P=0.388, P=0.810, P=0.584). Conclusions: Based on quantitative analysis of root filling void volume using micro-CT scanning, the short-term sealing abilities of the novel bioceramic root canal materials cRoot SP and nRoot SP in standardized root canals are comparable to that of the classical bioceramic sealer iRoot SP in vitro.