The Influence of a Manual Glide Path on the Separation Rate of NiTi Rotary Instruments

Abstract

The dual purpose of this study was, to evaluate the fracture rate of Ni-Ti rotary instruments when following a manual glide path and using stainless steel hand files before carrying out instrumentation by means of rotary files and, to compare the results in this study with those obtained in two previous analyses, in which the glide path technique was not used. A total of 208 canals obtained from a pool of freshly extracted human mandibular and maxillary molars was divided into three groups corresponding to; K3, ProFile and ProTaper. The coronal 2/3 of each tooth were used. In all three groups the apical portion of the samples was prepared with size 10-20 stainless steel K-type hand files. The apical stops were prepared using K3, ProFile and ProTaper rotary instruments. Logistic regression model analysis indicated that breakage was significantly associated with the angle of curvature of the canal (OR = 1.078; 95% CI = 1.032-1.12; p = 0.001), and with the number of clinical uses (files used more than eight times broke more frequently that those used 1 or 2 times; OR: 22.686; 95% CI: 2.6-191.3; p = 0.004). The breakage rate obtained in the present study is significantly lower than in our previous studies, in which the angle of curvature was also greater than 30 degrees and rotational speed a constant 350 rpm, but in which the canals were not first prepared with hand files (25/205 = 12% versus 16/61 = 26%, p = 0.007). Based on the results of this study, we recommend the use of stainless steel hand files to prepare the apical 1/3 of curved canals before introducing rotary files.

Postoperative Pain after Manual and Mechanical Glide Path: A Randomized Clinical Trial

“…This risk may be reduced by performing coronal enlargement (12,13) and by creating a glide path, either manual (14,15) or mechanical (16), before using NiTi rotary instrumentation. The new NiTi Rotary PathFile™ (PF) leads to significantly less modifications in coronal and apical canal curvature and to fewer canal aberrations compared with manual glide path with stainless-steel KFs, independently from the clinician's expertise (16).…”

Modifications in Canal Anatomy of Curved Canals of Mandibular First Molars by two Glide Path Instruments using C BCT

“…Coronal enlargement [17] and preliminary creation of a glide path are fundamental for safer use of NiTi rotary instrumentation [18,19]. Canal scouting and preflaring are the first phases of canal instrumentation during which the clinician might more frequently find procedural difficulties [20].…”

“…Indeed, preflaring permits to maintain a pathway to the full Working Length (WL), avoiding excessive instrument binding in the canal [18,19].…”

Obturation Over an S1 ProTaper Instrument Fragment in a Mandibular Molar with Three Years of Follow-up

“…Thus, adequate straight-line access and preparation of a glide path with passive use of NiTi rotary files into the canal are essential steps to prevent the occurrence of fracture (4,8). Furthermore, monitoring of reused files is important to identify signals of fatigue (3)(4)(5).…”