Mechanical Preparation Showed Superior Shaping Ability than Manual Technique in Primary Molars - A Micro-Computed Tomography Study

Abstract

The aim of the study was to evaluate canal preparation in primary molars with hand files, ProTaper Next and Self-Adjusting File (SAF) by 2D and 3D micro-computed tomography (micro-CT) analysis. Canals of 24 primary molars were prepared with hand files (HF), ProTaper Next (PTN) and SAF (n=8/group). The teeth were scanned before and after root canal preparation and the pre-and postoperative micro-CT images were reconstructed. Changes in 2D (area, perimeter, roundness, minor and major diameter) and 3D [volume, surface area, structure model index (SMI)] morphological parameters, as well as canal transportation and lateral perforations were evaluated (Kruskal-Wallis and ANOVA; α=0.05). SAF presented smaller changes in minor diameter, volume and surface area compared with HF and PTN (p<0.05). PTN presented more circular canals after preparation. 3D analysis revealed greater transportation in HF. PTN and SAF presented more centered canal preparation, especially in curved areas. SAF and HF presented, respectively, the lowest (0.05±0.02 and 0.07±0.04) and highest (0.14±0.11 and 0.29±0.17) apical transportation. There were fewer lateral perforations in SAF (4.2%) and PTN (7.7%) than in HF (47.8%) (p<0.05). In primary molars, mechanical preparation showed better shaping ability than hand files, promoting more centered preparations and lower occurrence of lateral perforations and canal transportation. Clinical Relevance: Manual instrumentation is still reported as the main choice in the primary teeth preparation; however, studies have shown limitations in its use. The morphological characteristics of primary teeth and the limited knowledge of shaping procedures in these teeth using mechanical preparation become a challenge for clinical practice and might impair the predictability of endodontic treatment.

A micro‐computed tomographic assessment of root canal preparation with conventional and different rotary files in primary teeth and young permanent teeth

“…In this study, all file systems similarly increased the SMI scores in primary teeth, indicating that the final three‐dimensional shapes were not different than their original counterparts. This finding is in line with a recent study which showed an increase in SMI scores after preparation with rotary and hand files, without a significant difference between the file systems. As for permanent teeth, Revo‐S and conventional hand files preserved the original three‐dimensional canal shape better than One Shape, which changed the original shape by forming a more round, cylindrical geometry.…”

“…Rotary files were first evaluated in primary teeth by Barr et al, who concluded that root canal preparation was faster with rotary files than with manual files, and produced uniform and predictable canal morphologies. Although few other studies have evaluated the performance of rotary file systems in the primary dentition, their outcomes are still limited to provide an exact conclusion.…”

Role of the Flat-Designed Surface in Improving the Cyclic Fatigue Resistance of Endodontic NiTi Rotary Instruments

“…The development of endodontic nickel–titanium (NiTi) rotary instruments have improved root canal shaping, making the treatment more feasible, repeatable, and faster [1,2,3]. Despite the superior mechanical properties of the NiTi alloy, the risk of intracanal separation of the nickel–titanium rotary instruments has been shown to increase when compared with the traditional stainless steel files [1].…”

Root canal conicity estimation of primary maxillary central and lateral incisors—A study by Nano‐CT

“…There is increasing scientific evidence in the literature from both in vitro [22][23][24] and clinical 25,26 studies evaluating different instruments and systems for biomechanical root canal preparation in primary dentition. Specifically, in anterior teeth, only Subramaniam et al 22 evaluated the effectiveness of hand and rotary files for smear layer removal in root canals of primary teeth by scanning electron microscope (SEM).…”