Internal morphology of distal roots of mandibular first molars revealed by computed microtomography.

To evaluate the internal morphology of 100 distal roots of mandibular first molars using micro-CT. Teeth were scanned to characterise: Vertucci type, root length, canal shape, presence and location of accessory canals, and the number of foramina at 4 mm from the apex, presence of root isthmus and the length from the primary canal to the apical foramen. Vertucci type I was found in 57% of cases, followed by V (27%). The most common cross-section 1 mm from the apex was oval (49%) and circular (38%). The average root length was 16.06 mm (16.61-19.02 mm). The mean foramen size was 0.32 and 0.53 mm for the minor and major diameters, respectively. The volume, surface area and SMI were 7.84 mm3 , 68.87 mm2 and 1.52 mm, respectively. Root isthmi were found in 47% of the samples, and the length mean from the primary canal to the apical foramen was 2,03 mm. The internal morphology of the distal roots of mandibular first molars may be complex and shows variations.

In vivo evaluation of painful symptomatology after endodontic treatment with or without the use of photodynamic therapy.

CONTEXT: Postoperative pain control after endodontic treatment is important to maintain patient comfort. AIM: The aim of this prospective clinical study was to evaluate the postoperative symptomatology of endodontic treatments performed in a single session, with or without photodynamic therapy (PDT), using Reciproc #40 file in necrotic unirradicular anterior teeth. MATERIALS AND METHODS: In a prospective clinical study, 40 teeth indicated for endodontic treatment were treated by a single endodontist according to a preestablished protocol. The teeth were randomly divided into two groups (n = 20): control group (CG) and laser group (LG). After 24 h, 72 h, and 1 week of endodontic treatment, patients' pain symptomatology was evaluated through a Visual Analog Scale (VAS) ranging from 0 to 10, in which 0 corresponds to no pain and 10 indicates extreme pain. In both workgroups, similar protocols were used for instrumentation with the Reciproc system (R40), irrigation with 2.5% sodium hypochlorite, and filling by the gutta-percha plastification technique, in which the CG did not use PDT, and the LG used PDT after the instrumentation sequence. After the visit, the patients were given a prescription for ibuprofen 400 mg to be taken every 6 h if they experienced pain. RESULTS: The results of the study, analyzing the VAS, did not show any difference in pain symptoms between the groups at 24 h, 72 h, and 1 week (P > 0.05). CONCLUSIONS: It was concluded that there was no statistical difference between the groups.

Micro-Computed Tomographic Evaluation of 2 Nickel-Titanium Instrument Systems in Shaping Root Canals.

INTRODUCTION: Cleaning and shaping without making procedural errors have always been a challenge in endodontics, particularly when the root canals are curved. Several rotary instruments have been developed to minimize such errors. The purpose of this study was to compare the shaping ability of 2 rotary file systems, BioRace (BR; FKG, La Chaux-de-Fonds, Switzerland) and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), during the preparation of curved root canals in extracted teeth using micro-computed tomographic imaging. METHODS: A total of 20 first and second human mandibular molars with 2 separate mesial canals were scanned before and after root canal preparations using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 µm. Canals were prepared using the BR and PTN systems. The percentage of dentin removed after preparation, root canal volume increase, untreated canal walls, structure model index, degree of canal transportation, and centering ability were also measured. RESULTS: There were no significant differences between the 2 groups in the removed dentin after preparation and determination of the root canal volume, percentage of untreated canal walls, structure model index, degree of canal transportation, and centering ability (P > .05). CONCLUSIONS: In conclusion, within the limitations of this ex vivo study, instrumentation of moderately curved mesial roots with 2 independent root canals and foramina using the BR and PTN rotary file systems were equally effective. Both instrumentation systems caused negligible procedural errors with minimal apical transportation.