The ability of three nickel–titanium mechanized systems to negotiate and shape MB2 canals in extracted maxillary first molars: a micro‐computed tomographic study

Abstract

AimTo evaluate the influence of three engine‐driven NiTi file systems manufactured from different NiTi alloys for the preparation of second mesiobuccal (MB2) canals in extracted maxillary first molars using a micro‐computed tomographic (micro‐CT) scanner.MethodologyThirty maxillary molars with two canals in the mesiobuccal root were selected and randomly divided into three groups (n = 10): Reciproc [REC; size 25, .08 taper; VDW, Munich, Germany], ProDesign R [PDR; size 25, .06 taper; Easy, Belo Horizonte, Brazil] and Mtwo [MO; size 25, .06 taper; VDW, Munich, Germany]. Before and after root canal preparation of the MB2 canal, the teeth were scanned using a micro‐CT to evaluate canal transportation, centring ability, dentine thickness and volume change. The working time to achieve working length was also evaluated. All parameters were compared statistically using the Kruskal–Wallis and Dunn test for multiple comparisons, with a significance level of 5%.ResultsThere was no significant difference amongst the groups regarding canal transportation and centring ability (P > 0.05). However, the PDR size 25, .06 taper group had significantly lower canal volume and volume of dentine removal compared with a MO size 25, .06 taper and REC size 25, .08 taper (P < 0.05). A root perforation was detected in MO size 25, .06 taper and REC size 25, .08 taper groups, respectively. Regarding the working time, the PDR size 25, .06 taper required a significantly longer time to achieve working length than MO size 25, .06 taper and REC size 25, .08 taper (P < 0.05).ConclusionsAll NiTi systems had similar canal transportation, centring ability and increase in apical volume after preparation of MB2 canals. However, the PDR size 25, .06 taper had less volume of dentine removal, absence of root canal perforation and required a longer time to accomplish the root canal preparation.

Effect of larger apical size on the quality of preparation in curved canals using reciprocating instruments with different heat thermal treatments

“…Therefore, in curved canals, even using heat‐treated instruments, it is expected that there will be a deviation towards the outer wall of the curvature (Camargo et al . ).…”

“…All systems had transportation at below 0.3 mm, which is considered by some studies to be the limit before a negative impact on clinical prognosis occurs (Camargo et al . , Pinheiro et al . ).…”

“…After root canal preparation, the increase in root canal volume, percentage of untouched areas and canal transportation were assessed using instruments with a size 25 tip and complemented with large apical preparation sizes. The methodology has been extensively used in several previous studies because it is an accurate and nondestructible method (De-Deus et al 2017, Duque et al 2017, Camargo et al 2018, Marks Duarte et al 2018.…”

“…A negative result indicated transportation to the outer region of the curvature, while a positive result indicated transportation to the inner region of the curvature (Camargo et al . , Pinheiro et al . ).…”

“…According to this formula, a result of 0 (zero) indicated absence of root canal transportation. A negative result indicated transportation to the outer region of the curvature, while a positive result indicated transportation to the inner region of the curvature (Camargo et al 2018, Pinheiro et al 2018).…”