Evaluation of 3D-printed oval root canal preparation by small field-of-view cone beam CT and computer-aided technique / 口腔疾病防治

Objective@# To evaluate the effect of 3D-printed oval root canal preparation by using small field-of-view cone beam CT (CBCT) combined with computer-aided technologies.@*Methods@#An extracted tooth with a suitable single oval canal was selected by small field-of-view CBCT scanning. Three-dimensional (3D)-printed resin teeth were obtained based on the CBCT data after data conversion and processing. 50 general dentists were selected to prepare the oval root canal of the resin teeth with X-Gold rotary Ni-Ti instruments. Small field-of-view CBCT was applied to scan the oval root canals before and after preparation. Then, computer-aided technologies were used to calculate and compare these CBCT data, analyzing the effects of oval root canal cleaning as well as the root canal deviation by 3D reconstruction and rendering of the images.@*Results @#Among the 50 cases, the mean unprepared area of the oval root canal wall was（56.20 ± 11.91）% and the mean maximum deviation distance of the root canal was（0.140 ± 0.041）mm. There was no correlation between root canal cleanliness and deviation (r=0.18, P=0.212).@*Conclusion @# Combined with small field-of-view CBCT and computer-aided technology, we can effectively quantitatively evaluate the root canal preparation effect.

A comparison of apical sealing ability of different root canal obturation techniques in oval root canals / 口腔疾病防治

Objective@# To investigate the effect of different root canal obturation techniques on apical sealing in oval root canals. @*Methods@#120 recently extracted human premolars with single oval canal were randomly divided into 6 groups, including single point obturation, warm gutta percha vertical condensation, cold lateral condensation obturation method combined with different root canal sealers (iRoot SP or AH-Plus). There're six groups in total, including single point iRoot group, warm gutta percha iRoot group, cold gutta percha iRoot group, single point AH group, warm gutta percha AH group, cold gutta percha AH group. @*Results @#Root depth of dye penetration in warm gutta percha iRoot group and warm gutta percha AH group were significantly lower than group single point iRoot group and single point AH group (P < 0.05), and root depth of dye penetration of warm gutta percha iRoot group, cold gutta percha iRoot group was less than warm gutta percha AH group, cold gutta percha group (P < 0.05), but there was no statistic difference between other groups (P > 0.05). @*Conclusion @#In root canal treatment, warm gutta-percha condensation technology can make the oval canal root achieve better sealing effect, using iRoot SP is better than using AH-Plus.

Apical sealing ability of iRoot SP in oval-root canals in vitro / 实用医学杂志

Objective To evaluate the apical sealing ability of iRoot SP root canal sealer in oval-root canal. Methods After root canals were instrumented by Mtwo, 28 premolars with oval-root canal were randomly divided into 2 groups, 14 teeth in each. The root canals were obturated with AH Plus (group A) and iRoot SP (group B) by modified continuous wave condensation technique. The apical leakage was evaluated by dye penetration method and transparent teeth technique. Results Mean depth of leakage was (0.92 ± 0.26) mm for group A and (0.84 ± 0.40) mm for group B. There was no significant difference between the two groups (t=0.506, P > 0.05). Conclusion The apical sealing ability of iRoot SP is equivalent to AH Plus in oval-root canal.