ABSTRACT
Objective: This study aimed to evaluate the canal cen-tering ability and topography of BioRaCeTM (BR), Wi-zard CD PlusTM (WP), and Wizard NavigatorTM (WN) instruments. Materials and method: mesiobuccal roots of upper first molars were selected and randomly dis-tributed in three groups (n=10), according to the rota-ry system used for instrumentation. Canal transporta-tion was assessed at 2, 4, 6, and 8 mm from the root apex, by subtracting cone bean computed tomography (CBCT) images taken before and after preparation. The root canal center was marked in pre- and post-prepa-ration images, and the distance between these points was measured in bucco-palatal (BP) and mesio-distal (MD) directions. New instruments were analyzed un-der scanning electron microscopy (SEM) regarding their surface finishing, topographical features, and surface defects. The SEM images were obtained at the tip of the instrument, and at 5 mm from the tip. Data of the canal centering ability were analyzed by two-way ANOVA (? = 0.05). Results: regardless of root level (2, 4, 6, and 8 mm), all groups presented canal transportation in both directions. Significant differences were not detected (p > 0.05). Surface finishing was regular in the BR group with rounded transitional angle. Cutting edges had a sharp angle in BR and WN groups, while WP instru-ments had a flattened angle. Conclusion: despite such topographical differences between the rotary instru-ments tested, none of them were able to exactly main-tain the original root canal center, and no significant differences were observed among groups.
ABSTRACT
Objective: this study aimed at evaluating which temporary restorative materials are recommended by Brazilian Dental Schools (BDS), during and after endodontic treatment completion. Methods: a questionnaire was distributed to all 191 BDS, and returned by 55 (28.8%)schools. Topics of interest included: which temporary restorative materials are advised in different remaining dental conditions and different permanence periods in the mouth, minimum material thickness, intermediate material application, use of matrix band and factors influencing material selection. Results: the answers showed that the remaining coronal tooth structure significantly interferes with the choice of temporary restorative materials. On the other hand, time between ap pointments does not have significant influence on material selection. Still, premixed hygroscopic materials are recommended in cases of simple endodontic access (occlusal or lingual/palatal) if the material will be kept for up to one week in the month. Glass ionomer cement (GIC) is the most commonly used material in long periods, especially for access cavities involving proximal surfaces or fractured cusps. The utilization of an intermediate material is very variable and some schools do not advocate any material. Most BDS recommend a minimum thickness of 3 mm for temporary restorations and the use of matrix band in proximal surfaces. Conclusion: BDS choices with respect to coronal sealing materials are driven especially by remaining dental conditions.