Abstract
Objective: This study evaluated the residual dentin thickness (RDT) of maxillary premolars after the use of different cervical preflaring (PF) drills by using cone-beam computed tomography (CBCT). Methods: Eighty bifurcated maxillary premolars were accessed and randomly divided into 5 groups (n=16). PF was performed with Gates-Glidden #1, #2, and #3 (group 1), Largo #1 and #2 (group 2), and LA Axxess #20/.06 (group 3), #35/.06 (group 4), and #45/.06 (group 5). CBCT images were acquired before (preoperative) and after (postoperative) PF. Initial and final cervical dentin thickness was measured at the buccal, palatal, mesial, and distal aspects, 0.5 mm coronally to the furcation, on both buccal and palatal roots, using CBCT’s image analysis software. The percentage of removed dentin after PF preparation was also calculated. Data were analyzed using ANOVA followed by Tukey’s test at a significance level of P < 0.05. Results: No statistically significant differences were found among the groups for preoperative or postoperative RDT (P > 0.05). LA Axxess #20/.06 (group 3) removed significantly less cervical dentin at all root canal aspects on both buccal and palatal roots. The mesial aspect of the buccal root and distal aspect of the palatal root were significantly reduced after the use of LA Axxess #45/.06 (group 5) and Largo #1 and #2 drills (group 2), respectively (P < 0.05). Conclusion: PF in bifurcated maxillary premolars should be performed with LA Axxess instrument #20/.06. The use of Gates-Glidden #1, #2, and #3, Largo #1 and #2, and LA Axxess #45/.06 drills should be done with caution.
Highlights
Contemporary guidelines for cleaning, shaping, and disinfection of root canals emphasize the importance of the removal of dentin interferences along the cervical and middle thirds prior to apical instrumentation [1]
The lowest values of the residual dentin thickness (RDT) were observed in the mesial of group 5 (LA Axxess #45/.06 group; 1.33 ± 0.30;) and distal of group 2 (Largo #1 and #2; 1.33 ± 0.20) aspects of the buccal root canal and distal aspect of group 2 (Largo #1 and #2 group; 1.16 ± 0.19) of a palatal root canal, no significant difference was observed among groups (P>0.05)
The present study aimed to compare the effect of GG, Largo and LA Axxess drills on cervical dentin thickness of bifurcated maxillary premolars by using cone-beam computed tomography (CBCT)
Summary
Contemporary guidelines for cleaning, shaping, and disinfection of root canals emphasize the importance of the removal of dentin interferences along the cervical and middle thirds prior to apical instrumentation [1]. The presence of bifurcated roots with variable degree of curvature, narrow furcation entrance, deep mesial concavities, various pulp cavity configurations, and multiple canals and apical foramina [14, 15] makes the endodontic management of these teeth a real challenge [12, 15]. Furcation groove on the palatal aspect of the buccal root is another relevant anatomic feature, commonly observed in bifurcated maxillary premolars [12, 14, 16]. The existence of a furcation groove has clinical importance for endodontic and prosthodontic treatment planning [12, 14] because its presence may result in inconsistent wall thickness at the different aspects of the root [1, 13, 15], which could predispose to the occurrence of unpleasant operative accidents [17]. There is no consensus about the clinical and radiographic parameters that should be considered when choosing the type and size of the instrument for the enlargement of cervical and middle thirds [5], which means that in daily clinical practice, the choice of PF instrument has been based on personal preference
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