Ex vivo analysis of the debris remaining in flattened root canals of vital and nonvital teeth after biomechanical preparation with Ni-Ti rotary instruments

Abstract

The purpose of this study was to assess the presence of apical debris remaining in the apical third of flattened root canals of vital and nonvital teeth after biomechanical preparation with Ni-Ti rotary instruments. Fresh-extracted human mandibular incisors were used in this study. The teeth had clinical indication for extraction and were submitted to cold pulp vitality testing and radiographic examination. Eighteen teeth were selected and randomly assigned to two groups (n=9), according to the clinical diagnosis, i.e., pulp vitality or pulp necrosis. The canals were instrumented with the ProTaper NiTi rotary system in the following sequence: S1 -up to the middle third; SX -at the cervical third; S2-up to the apical third; and S1, F1, F2, F3 -at the working length. The canals were irrigated with 1% sodium hypochlorite, dried and were submitted to the histological processing. Sections from the apical third were analyzed by an optical microscope (X40) that was coupled to a computer where the images were captured and analyzed using specific softwares. A grid was placed over these images to assess the total canal area and the areas with debris. Mann-Whitney U-test showed no statistically significant difference (p>0.05) between the teeth with pulp vitality (6.49 ± 3.39) and those with pulp necrosis (5.95 ± 2.22). It may be concluded that the clinical condition of pulp tissue did not interfere with the amount of debris remaining in the apical third of flattened root canals prepared with Ni-Ti rotary instruments.

Sodium Hypochlorite with Reduced Surface Tension Does Not Improve In Situ Pulp Tissue Dissolution

“…The first one was about the prospective in vivo selection of vital teeth. This is an essential methodological step in assuring the credibility of the histological assessment (16,17). Only by using a rigorous and well-controlled tooth selection can the root canal contents be standardized with a minimal standard of control (16).…”

Flat-Oval Root Canal Preparation with Self-Adjusting File Instrument: A Micro–Computed Tomography Study

“…Although many technical advances have been made in endodontics, canal preparation is still adversely influenced by the highly variable anatomy (1,3,4), especially in oval, flat, or curved root canals (5)(6)(7)(8)(9). In flat-oval canals, rotary files have failed to perform adequate cleaning and shaping, leaving untouched fins or recesses on the buccal and/or lingual aspects of the central canal area prepared by the instrument (5,6,9,10).…”

Análise Da Capacidade De Limpeza De Três Técnicas De Instrumentação Em Canais Radiculares Achatados: Diaphanization Study

“…(13)(14)(15)(16) Flattened or oval canals studies use the mesial root of molars (17,18) or mandibular incisors. (5,10,19,20) Extracted mandibular incisors were used in this study by having a pronounced flattening on the mesiodistal direction, which can generate a second canal lingually located to the main one, as well as the occurrence of severely flattened canals, with elongated cross-section, being the biggest diameter on the buco-lingual direction. (13) Mandibular incisors with more than one root canal were excluded and only the ones with mesiodistal flattening were used.…”