According to our findings and the results of the clinical trial, the occurrence of postoperative pain was low and similar between the reciprocating and rotary techniques during the time intervals assessed. These results are different from basic laboratory studies that affirm that the reciprocating techniques tend to promote more postoperative pain since extrusion of debris is greater.

Biomechanical preparation of root canals with accentuated curvature is challenging. New rotatory systems, such as Reciproc, require a shorter period of time to prepare curved canals, and became a viable alternative for endodontic treatment of teeth with root dilaceration. Thus, this study aimed to report a clinical case of endodontic therapy of root with accentuated dilaceration using Reciproc single-file system. Mandibular right second molar was diagnosed as asymptomatic irreversible pulpitis. Pulp chamber access was performed, and glide path was created with #10 K-file (Dentsply Maillefer) and PathFile #13, #16 and #19 (Dentsply Maillefer) up to the temporary working length. The working length measured corresponded to 20 mm in the mesio-buccal and mesio-lingual canals, and 22 mm in the distal canal. The R25 file (VDW GmbH) was used in all the canals for instrumentation and final preparation, followed by filling with Reciproc gutta-percha cones (VDW GmbH) and AH Plus sealer (Dentsply Maillefer), using thermal compaction technique. The case has been receiving follow-up for 6 mon and no painful symptomatology or periapical lesions have been found. Despite the difficulties, the treatment could be performed in a shorter period of time than the conventional methods.

This study aimed at evaluating the changes in surface characteristics and NiTi content of reciprocating and rotary instruments after continuous use. Thirty brand-new instruments were assigned to 3 groups (n=10): PNX1 Group -ProTaper Next system -instrument X1; PNX2 Group -ProTaper Next system -instrument X2 and WO Group -WaveOne system -Primary instrument 25.08. The instruments were used to prepare 60 simulated root canals. Analysis of surface characteristics by scanning electron microscopy (SEM) and chemical analysis of Ni and Ti content by energy-dispersive spectroscopy (EDS) were performed before and after the first and third use of the instruments. Only WO Group had significant increase in the quantity of defects and deformations after the third use (p<0.05). PNX1 Group had significant decrease in Ni content after the third use, in comparison with the unused instruments (p<0.05). PNX1 Group had no decrease in Ti content throughout the time of use (p>0.05), however, in PNX2 Group, there was significant decrease in the different time interval of analysis (p<0.05). Continuous use promoted increase in defects and deformations only for WaveOne instruments. Chemical composition presented significant changes according to the time of instruments use.

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a b s t r a c t a r t i c l e i n f oMethods: Sixty-six mandibular premolars were prepared and randomly distributed into three groups, according to the root canal sealer used for filling, as follows: G1 AH Plus (Dentsply-Maillefer), G2 MTA Fillapex (Ângelus) and Sealapex (Kerr Corporation). After one week in an oven (37°C, 100% humidity), the teeth were immersed in India ink for 15 and 30 days (n = 10), and then submitted to diaphanization to verify the amount of coronal microleakage using an operating microscope. The values were statistically analyzed using Kruskal-Wallis test (p < 0.05).Results: MTA Fillapex had the highest coronal microleakage values, in both periods (15 and 30 days). Coronal microleakage mean values were only significant in comparison with AH Plus group at the 15 day-period (p < 0.05).Conclusions: None of the tested cements was able to prevent coronal microleakage. However, MTA Fillapex had the worst results at 15 days. Métodos: Sessenta e seis pré-molares inferiores foram preparados e distribuídos aleatoriamente em três grupos, de acordo com o cimento endodôntico utilizados para obturação, da seguinte maneira: G1 AH Plus (Dentsply-Maillefer), G2 MTA Fillapex (Ângelus) e Sealapex (Kerr Corporation). Depois de uma semana em estufa (37°C, 100% de humidade relativa), os dentes foram imersos em corante durante 15 e 30 dias (n = 10), e em seguida, submetidos a diafanização para verificar a quantidade de infiltração coronária utilizando microscópio operatório.