Evaluation of the risk of a stripping perforation with gates-glidden drills: serial versus crown-down sequences

Abstract

The aim of this study was to evaluate the remaining dentine/ cementum thickness using Gates-Glidden burs in serial and crown-down sequences and to observe which of the two sequences is the safest for preparing mesial roots of molars. Thirty-six left and right human mandibular first molars were selected. Standard access cavities were made and initially explored with Flexofiles sizes 10 and 15 until the tip was visible at the apex. The teeth were embedded in a muffle specially developed for this study using a PVC tube with two parallel metal rods in its lid. Each tooth-block was sectioned 3 mm apically to the furcation using a low-speed saw with a diamond disc. The tooth-block was examined under a microscope and an initial image was captured by a digital video system with 8 X and 12 X magnifications. Finally, the tooth-blocks were reassembled in the muffle so that the canals could be instrumented. After instrumentation the area of each mesial canal as well as the smallest distance to the root furcation were measured again. The mesio-buccal canals (crown-down order) and the mesio-lingual canals (serial sequence) presented an average area of 0.46 0.16 mm 2 and 0.88 0.27 mm 2 (P 0.01), respectively. The mean values of the smallest distance to the furcation for the mesio-buccal and mesio-lingual canals were 0.66 0.19 mm and 0.39 0.13 mm (P 0.01), respectively. The remaining dentine/cementum thickness using Gates-Glidden burs was greater in the crown-down sequence than in the serial sequence.

The dentin thickness remaining in the risk zone of mandibular molars after cervical preflaring with four methods

“…The present study found similar rates of dentin removal compared to previous studies 4,[9][10][11][12][13][14][15]24 .…”

“…On the other hand, as they were made of stainless steel and had limited flexibility, their use leads to risks especially in the lower molars mesial root, as its excessive enlargement may lead to wear of lateral perforation of the root, named "Strip Perforation" 10,11 . This accident may affect the treatment prognosis since it may reduce the treatment success rates [12][13][14] .…”

Morphometric evaluation and planning of anticurvature filing in roots of maxillary and mandibular molars

“…This fact demonstrates that it is not always necessary for canals to be accessed with files at a vertical straight line after anticurvature filing, as suggested by some studies. 1,5,6,7,9,10,17 The straight access of files in a vertical line after anticurvature filing simulation was possible in only 29% of mesiobuccal canals from maxillary molars and in 46% of mesial canals from mandibular molars. In the other cases, reaching straight file access would require excessive removal of dentin from coronal and cervical third regions, which can lead to weakening of tooth structure, thus increasing the risk of vertical root fractures ( Figure 3A).…”

“…Several investigations have been carried out on the danger zones in curved canals, 11,12,17 but studies on the filing of the safety zone are still lacking.…”

Computed tomography evaluation of residual root thickness after pre-flaring using gates Glidden drills: The sequence effect

“…[4] The low price, high cutting potential and easy use of Gates-Glidden (GG) drills have made them widely-used instruments in coronal preparation of root canals. [7] GG reamers to No. 2 in the coronal third of mesiobuccal canal did not significantly decrease the residual dentin thickness.…”