Cone-beam computed tomography analysis of the apical third of curved roots after mechanical preparation with different automated systems

Abstract

The present study evaluated by cone-beam computed tomography (CBCT) the apical canal transportation and centralizing ability of different automated systems after root canal preparation. The mesiobuccal canals of maxillary first molars (n=10 per group) were prepared with: GI - reciprocating system with K-Flexofile; GII - reciprocating system with NiTiFlex files; GIII - rotary system with K3 instruments; GIV - rotary system with RaCe instruments. CBCT scans were taken before and after biomechanical preparation up to a #40.02 diameter. Canal transportation was determined by measuring the smallest distance between the inner canal walls and the mesial and distal sides of the root. The centralization ability corresponded to the difference between the measurements from transportation evaluation, using the linear voxel to voxel method of analysis. The mean transportation was 0.06 + or - 0.14 mm, with a tendency to deviate to the mesial side of the root (n=22), with no statistically significant difference among the groups (p=0.4153). The mean centralization index was 0.15 + or - 0.65 also without statistically significant difference among the groups (p=0.0881). It may be concluded that apical canal transportation and centralization ability were not influenced by the type of mechanical movement and instruments used.

Retracted: Micro‐computed tomography evaluation of apical transportation and centring ability of Reciproc and WaveOne systems in severely curved root canals

“…Several studies have reported similar results (Oliveira et al 2009, Pasternak-Júnior et al 2009). However, Peters et al (2001) demonstrated that there is no constant pattern as regards the direction of apical transportation.…”

Assessment of canal centering ability and topography of three nickel- titanium rotary systems

“…Endodontic literature has yet to clearly establish an association between canal curvature and transportation directions. Whereas, some studies using mesiobuccal canals showed tendency toward mesial transportation 19,25 , which has been attributed to curvatures frequently observed in a distal positions. Meanwhile, other authors have stated that the direction of canal curvature has no effect on the direction of transportation 28 .…”

“…The results observed herein showed that, generally, BR, WP, and WN instruments produced similar canal transportation, which was also comparable with the amount of deviation produced by other commonly employed rotary systems 7,20 . Recent studies have shown that NiTi files did not avoid the occurrence of apical transportation 5,19,21 , but this deviation is reduced when compared to manual techniques 4,6,7 .…”

“…As well as previous studies 5,7,16,19,21 , this investigation used CBCT images to assess the centering ability of different instruments. Besides being a non--destructive and accurate method, this technique allows observation in both MD and BP directions, which is not possible when applying conventional radiographs 27 .…”

Partial volume correction for approximating crack opening displacements in CFRP material obtained from micro-focus X-ray CT scans

“…Since a crack that partially fills a voxel may be treated as occupying a full voxel when interconnected measurements are taken, overestimations in measurements occur [16][17][18]. This phenomenon is particularly noticeable at phase boundaries that fall within a voxel, leading to intermediate voxel intensities dependant on the percentage of "fill" between both phases [16,19,20].…”