Negotiating the second mesiobuccal canal: A comparison of nickel titanium files through the experience of undergraduate dental students.

OBJECTIVES: The aim of this study was to compare the ability of undergraduate students to reach working length (WL) in second mesiobuccal root canals (MB2) of maxillary first molars (n = 210) by using Reciproc Blue without glide path preparation, and One Curve with glide path preparation. METHODS: The students (n = 105) attended theoretical and practical courses. The first group (n = 53) shaped MB2 root canals using the One Curve system and then Reciproc Blue; the second group (n = 52) shaped MB2 root canals following the reverse sequence. Participants completed a questionnaire. The chi-square and Mann-Whitney U test were used for statistical analysis using significance of p < 0.05. RESULTS: The full WL was reached and shaping procedures were completed without complications in Reciproc Blue and One Curve groups at rates of 86.67% and 82.85%, respectively (p > 0.05). Treatment time was shorter in Reciproc Blue (p < 0.05). More (62.9%) students felt the One Curve system safer, while 61% felt the Reciproc Blue system faster. CONCLUSIONS: Within the limitations of this study, instrument kinematics and glide path preparation did not interfere with undergraduate students' ability to achieve the WL in MB2 root canals.

A CBCT based digital analysis of shaping ability of Max Wire® alloy file in the treatment of large and curved root canals

Aim: To evaluate the limits of the shaping ability of MaxWire® alloy file in the treatment of pre-created large and curved root canals with different apical sizes by using cone-beam computed tomography (CBCT). Materials and methods: Forty-five permanent maxillary first molars with moderately curved palatal roots (20°-30°) were divided into three groups, and large root canals were created with apical diameter #35 (Group 1), #40 (Group 2) or #50 (Group 3) by using BioRace NiTi System. Then, they were reshaped with the MaxWire alloy file, XP-endo Shaper®. Canals were scanned before and after instrumentation by using the CBCT scanner. Canal transportation (CT), centering ratio (CR), % increased prepared area (PA), and % increased prepared outline (PO) at 2, 3, and 4 mm from the apex were calculated. Data were statistically analyzed at P < 0.05. Results: There was a significant difference in the mean increase in PO in all apical sizes and all three levels. At both 3 mm and 4 mm levels the maximum PA and PO were achieved in apical size 35, while at 2 mm level the maximum values were obtained in apical size 40. There was no statistically significant difference in CT and CR within groups at 2 mm distance from the apex. Conclusion: Max Wire alloy technology of this novel instrument makes it possible to clean and touch the dentin walls of large and curved root canals. Small FOV and small voxel size of CBCT could also be used in shaping ability studies in endodontics.

Effect of a novel bioceramic root canal sealer on the angiogenesis-enhancing potential of assorted human odontogenic stem cells compared with principal tricalcium silicate-based cements.

OBJECTIVE: This study evaluated the angiogenesis-enhancing potential of a tricalcium silicate-based mineral trioxide aggregate (ProRoot MTA), Biodentine, and a novel bioceramic root canal sealer (Well-Root ST) in human dental pulp stem cells (hDPSCs), human periodontal ligament stem cells (hPLSCs), and human tooth germ stem cells (hTGSCs). METHODOLOGY: Dulbecco's modified Eagle's medium was conditioned for 24 h by exposure to ProRoot MTA, Biodentine, or Well-Root ST specimens (prepared according to the manufacturers' instructions). The cells were cultured in these conditioned media and their viability was assessed with 3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H tetrazolium (MTS) on days 1, 3, 7, 10, and 14. Angiogenic growth factors [platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF-2), and vascular endothelial growth factor (VEGF)] were assayed by sandwich enzyme-linked immunosorbent assay (ELISA) on days 1, 7, and 14. Human umbilical vein endothelial cell (HUVEC) migration assays were used to evaluate the vascular effects of the tested materials at 6-8 h. Statistical analyses included Kruskal-Wallis, Mann-Whitney U, and Friedman and Wilcoxon signed rank tests. RESULTS: None of tricalcium silicate-based materials were cytotoxic and all induced a similar release of angiogenic growth factors (PDGF, FGF-2, and VEGF) (p>0.05). The best cell viability was observed for hDPSCs (p<0.05) with all tricalcium silicate-based materials at day 14. Tube formation by HUVECs showed a significant increase with all tested materials (p<0.05). CONCLUSION: The tricalcium silicate-based materials showed potential for angiogenic stimulation of all stem cell types and significantly enhanced tube formation by HUVECs.

Effect of a novel bioceramic root canal sealer on the angiogenesis-enhancing potential of assorted human odontogenic stem cells compared with principal tricalcium silicate-based cements

Abstract Objective: This study evaluated the angiogenesis-enhancing potential of a tricalcium silicate-based mineral trioxide aggregate (ProRoot MTA), Biodentine, and a novel bioceramic root canal sealer (Well-Root ST) in human dental pulp stem cells (hDPSCs), human periodontal ligament stem cells (hPLSCs), and human tooth germ stem cells (hTGSCs). Methodology: Dulbecco's modified Eagle's medium was conditioned for 24 h by exposure to ProRoot MTA, Biodentine, or Well-Root ST specimens (prepared according to the manufacturers' instructions). The cells were cultured in these conditioned media and their viability was assessed with 3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H tetrazolium (MTS) on days 1, 3, 7, 10, and 14. Angiogenic growth factors [platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF-2), and vascular endothelial growth factor (VEGF)] were assayed by sandwich enzyme-linked immunosorbent assay (ELISA) on days 1, 7, and 14. Human umbilical vein endothelial cell (HUVEC) migration assays were used to evaluate the vascular effects of the tested materials at 6-8 h. Statistical analyses included Kruskal-Wallis, Mann-Whitney U, and Friedman and Wilcoxon signed rank tests. Results: None of tricalcium silicate-based materials were cytotoxic and all induced a similar release of angiogenic growth factors (PDGF, FGF-2, and VEGF) (p>0.05). The best cell viability was observed for hDPSCs (p<0.05) with all tricalcium silicate-based materials at day 14. Tube formation by HUVECs showed a significant increase with all tested materials (p<0.05). Conclusion: The tricalcium silicate-based materials showed potential for angiogenic stimulation of all stem cell types and significantly enhanced tube formation by HUVECs.

A comparison of the shaping effects of 5 nickel-titanium rotary instruments in simulated S-shaped canals.

OBJECTIVE: The objective of this study was to compare the shaping efficacy of 5 Ni-Ti rotary instruments with different cross-sectional designs in simulated S-shaped resin root canals. STUDY DESIGN: One hundred canals (n = 20) were instrumented to apical size 0.04/25 with ProFile, K3, NiTi-TEE, EndoWave, or HeroShaper. Pre- and postoperative images were superimposed. Width of resin removal was measured. Total amount of material removal, amount and direction of transportation, and centering ratios were determined. Data were analyzed using 1-way ANOVA and post hoc Tukey and Newman-Keuls multiple comparison tests. RESULTS: In terms of centering ratio and amount of transportation, ProFile followed by K3 gave the best results almost throughout the whole canal. However, ProFile created insufficient taper. Canals instrumented with the other 3 systems were transported and lacked flow. CONCLUSION: The K3 system, probably owing to its cross-sectional design and sequence encompassing a high number of instruments, seems under the conditions of this study to be a better choice in preparing S-shaped simulated root canals.