For the root canal treatment to be successful, the root canal system must be cleaned and shaped, and must be gradually widened from the apical to the coronal region in order to preserve dentin thickness. ProFit S3 (Profit Dental, India) patented rotary file with variable taper design preserves dentin. The study employs ultra-high-resolution nano-computed tomography to assess the volumetric changes of two new rotary files in permanent mandibular premolars. Based on inclusion and exclusion criteria, this in-vitro investigation used extracted premolars. Before the pre-operative scan, samples were made and the working length was determined using a high-precision nano-CT (SkyScan 2214, Bruker, Kontich, Belgium). A single skilled pediatric dentist used ProFit S3 (Profit Dental, India) and Protaper Gold (PTG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) to prepare the canals. Post-op scans were similar to pre-ops. For 3D root canal visualization and analysis, NRecon software was used to rebuild images. Profit S3 has a mean value of 0.65500 and Protaper gold 1.38800, indicating a significant range. Protaper gold followed Profit S3 in canal volume differential. The two rotating file systems differed significantly (p 0.05). ProFit S3 maintained mesiodistal and buccolingual dentin thickness at 4 mm, 8 mm, and 12 mm, followed by Protaper Gold. ProFit S3 exhibited the lowest mean canal volume difference compared to Protaper gold. Unlike Protaper Gold, ProFit S3 offers a variable taper design that preserves root canal anatomy, peri cervical dentin, and dentin thickness.

To analyze the remaining dentin thickness and crack formation after retreatment, comparing three file systems.

Aim: To analyze the efficacy of various heat-treated retreatment file systems on the apical deformity and canal centering ability in single-rooted teeth using nano CT. Materials and Methods: A total of 45 single-rooted teeth were decoronated to 18mm and obturated. Three retreatment file systems were used, such as: Group 1- Solite RS3 Retreatment, Group 2- Solite RS3 Black Retreatment, and Group 3 - Solite RE Black Retreatment. All these procedures were carried out by a single operator. Nano-Computed tomography (CT) scans, pre- and post-operative, were obtained and superimposed for analysis. One-way ANOVA and post hoc tests were done to test the significance between the three groups. Results: Based on the results, it was inferred that the Solite RE Black file system had better canal centering ratio and less apical deformity during the retreatment compared to Solite RS3 and Solite RS3 Black (p<0.05). Conclusion: Solite RE Black file systems had superior centering ability in all apical thirds and less transportation in the middle and coronal thirds when compared to the other two retreatment file systems.

Background/Objectives: Non-surgical retreatment aims to remove infected filling material, prepare the canal for disinfection, and re-obturate. This ex vivo study evaluated the residual filling material and dentin volume removed after retreatment using a rotary or reciprocating system. Methods: Twenty mesial roots of mandibular molars with two independent, straight canals were decoronated to a 16 mm working length and obturated. Pre-operative nano-CT scans measured the initial dentin and filling material volumes. Specimens were randomly assigned to two groups: Solite RE Black system (RE1-30/0.08; RE2-20/0.06) and WaveOne Gold—small file (20/0.07). Post-operative nano-CT scans were superimposed to calculate the remaining filling material and dentin volume removed. Data are presented as the mean ± SD, and groups were compared using independent t-tests. Results: Neither system completely removed the intracanal filling material. The mean residual filling material volume was 1.42 ± 0.21 mm³ (Solite RE Black) vs. 1.56 ± 0.27 mm³ (WaveOne Gold), representing approximately 14% vs. 16% of the initial filling material, respectively (p < 0.05). Mean dentin volume removed was 0.95 ± 0.18 mm³ vs. 1.12 ± 0.22 mm³, with no significant difference (p > 0.05). Conclusions: In single-rooted, straight canals, Solite RE Black removed more filling material than WaveOne Gold, while dentin loss was similar. These findings are specific to straight canals, and further studies are required for curved or multi-rooted teeth.