No abstract

Purpose. The aim of this in vitro study was to evaluate the quality of four root canal obturation techniques using microcomputed tomography (micro-CT). Materials and Methods. A total of 36 mandibular first premolars with mostly round canals were decoronated, then instrumented up to a size F3 rotary file, and dressed with an epoxy resin-based sealer. Subsequently, they were divided into 4 different groups ( n = 9 ) based on the method of obturation: lateral condensation using 0.02 tapered master cone (LC2), lateral condensation using 0.04 tapered master cone (LC4), matched single-cone technique (MS), and matched single cone-mediated ultrasonic activation (MSUA). All the teeth were scanned using micro-CT (resolution of 19 μm), and the percentage volume of voids was calculated. One-way analysis of variance and Tukey test were used to analyze the data ( α = 0.05 ). Results. The total percentage volume of voids was significantly lower in the MSUA group compared to all other groups ( P < 0.05 ). The total percentage volume of voids was significantly lower in the MS group compared to the LC4 ( P < 0.001 ) and LC2 ( P < 0.001 ) groups. However, there was no significant difference between the LC2 and LC4 groups ( P < 0.65 ). Conclusions. MSUA, significantly, showed the least root canal filling voids amongst all the obturation techniques studied. MSUA can be considered an effective method for the filling of the round root canals. In general, lateral condensation using either 0.02 or 0.04 tapered master cones had significantly the highest volume percentage of voids amongst the experimental groups.

Background and Aim: Therapeutic effects of calcium hydroxide as an intra-canal medicament depend on its decomposition into hydroxyl and calcium ions. The aim of this study was to determine the diffusion amount of calcium ion and ph changes around the tooth root in the application of conventional calcium hydroxide and Nano particle calcium hydroxide at different times. Material and Methods:In this in vitro experimental study, 50 human single rooted and single canal teeth were divided into two experimental groups of 20 (conventional calcium hydroxide and Nano particle calcium hydroxide with a size of 23±5 nm after confirmation by X-ray Powder Diffraction) and a control group of ten (distilled water). After applying these materials using a K file ISO # 55, seal the coronal part of the canals and transfer to normal saline, the concentration of calcium ions and the ph of normal saline in all groups was measured After 3, 24, 96, 360 and 720 hours. Data were analyzed by one-way ANOVA, Tukey Post Hoc, Bonferroni Post Hoc statistical tests and SPSS 22 software. Results:There was a significant difference between the three groups at different times and in total in comparing the mean ph and mean concentration of calcium ions around the tooth roots (P <0.001). These values for both parameters, in the group of nanoparticle calcium hydroxide were significantly higher than conventional calcium hydroxide and in the group of conventional calcium hydroxide, higher than the control group (P <0.05). Also, the mean concentration of calcium ions in the group of normal calcium hydroxide and nanoparticle calcium hydroxide incresaed. Conclusion:Nanoparticle calcium hydroxide can be a suitable alternative to achieve the desired therapeutic goals due to its ability to emit more calcium ions and higher ph than the conventional type.

Introduction: Maxillary molars usually have three roots, four canals and the extra canal often exists in the mesiobuccal root. This study aimed to investigate the root morphology of maxillary first and second molars using CBCT. Materials & Methods: In this descriptive-analytical study, CBCT samples of 200 patients referred to maxillofacial radiology centers were selected and evaluated. Two-dimensional images in panoramic, cross-sectional, and transverse axial planes and three-dimensional images of the maxilla building that were reconstructed by a computer were examined. Analyzed data using one-way ANOVA and t-test (p value < 0.05) Results: The highest number of roots in the first molar was 3 (89.5%) and, the highest number of the second molar was 3 (90%). The maximum number of root canals in the first molar was 4 (65%) and, the highest number of root canals in the second molar was 3 (68%). The MB2 canal of maxillary first molars was 67.5% and the MB2 canal of maxillary second molars was absent at 71.5%. The presence of MB2 canal of maxillary first and second molars had no significant difference (p value > 0.05), but the presence of MB2 canal of maxillary first and second molars was significant (p value < 0.001). Conclusion: There is a significant relationship between being unilateral and bilateral with the presence of the mesiobuccal canal. Most of the first maxillary molars and, maxillary second molars had three separate roots. Also, there was no significant relationship between gender and side of study with the presence of mesiobuccal canal.