Aim: The aim of this in vitro study was to evaluate the effect of two different chemomechanical caries removal (CMCR) agents on dentin microhardness. Materials and Methods: In this study, the crown portion of ten carious-free and ten caries-affected teeth were selected. In carious-free samples, the teeth were decoronated at the level of cemento - enamel junction. Only the crown portion of the teeth was selected. Occlusal one-third of the crowns were cross-sectioned and discarded to expose the dentin, and it was divided into two groups, five teeth in each group. Then, they were further sectioned longitudinally through the centre. In one group, no agent was applied on one half and Carisolv was applied on other half. In another group, no agent was applied on one-half and Carie-Care was applied on the other half for 1 min. In carious samples, the crowns were sectioned through the centre of carious lesion. Carisolv was applied on one-half and Carie-Care was applied on the other half. After using CMCR agents, surface hardness of dentin was examined using Vickers hardness number (VHN). Statistical Analysis and Results: The data were analyzed using t-test and one-way analysis of variance (ANOVA). There were no significant difference among normal dentin (62.91 ± 2.76), Carisolv-treated normal dentin (61.72 ± 2.89), and Carie-Care-treated normal dentin (61.90 ± 3.19). In carious samples, the results of Carisolv-treated dentin (58.57 ± 2.62) was not statistically significantly different from those of the Carie-Care-treated dentin (56.77 ± 4.41). Conclusion: In conclusion, neither of the CMCR methods caused a significant change in the microhardness of normal dentin and the treated carious dentin.

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.