The aim of this study was to evaluate the effects of large apical preparations in the danger zones of the mesial root canals of mandibular molars instrumented with the Mtwo and Reciproc systems (VDW, Munich, Germany) until reaching apical diameters of 0.25 and 0.40 mm.
Twelve mandibular molars, the mesial roots of which presented distinct foramens and similar anatomies, were selected using micro–computed tomographic scanning. Mtwo and Reciproc instruments were used to shape the mesiobuccal or mesiolingual canals. The mesial canals were scanned before and after the use of 0.25- and 0.40-mm Mtwo and Reciproc instruments. The analyzed parameters included the root canal volume and remaining dentin thickness at 5 different levels. The obtained data were subjected to paired analysis of variance and Tukey or Friedman and Dunn tests for intragroup analysis and the Mann-Whitney U test for comparison between the mesial and distal walls.
There were no significant differences between the mesial and distal dentin thickness for the points analyzed with both instrumentation techniques (P > .05). The volumetric analysis revealed a significant difference (P < .05) among the initial volume and after the use of the 0.25- and 0.40-mm instruments for both systems. The use of the 0.40-mm instrument increased the root canal volume in comparison to the 0.25-mm instrument (P < .05).
Both systems performed similarly for the preparation of curved root canals with separate apical foramens. The increase of the root canal preparation with the 0.40-mm instrument significantly increased the root canal volume at the apical third without significantly reducing the dentin thickness in the danger zone for both instrument systems.
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- Cleaning and shaping the root canal.Dent Clin North Am. 1974; 18: 269-296
- Mechanical preparation of root canals: shaping goals, techniques and means.Endod Topics. 2005; 10: 30-76
- The effect of preparation procedures on original canal shape and on apical foramen shape.J Endod. 1975; 1: 255-262
- Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth.Int Endod J. 2006; 39: 203-212
- Root canal preparation with the NiTi systems K3, Mtwo and ProTaper.Aust Endod J. 2007; 33: 73-81
- An evaluation of the influence of passive ultrasonic irrigation on the seal of root canal fillings.Int Endod J. 2007; 40: 356-361
- Effect of apical preparation size and preparation taper on irrigant volume delivered by using negative pressure irrigation system.J Endod. 2010; 36: 721-723
- Homogeneity and adaptation of endodontic fillings in root canals with enlarged apical preparation.Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009; 108: e141-e146
- Increased apical enlargement contributes to excessive dentin removal in curved root canals: a stepwise microcomputed tomography study.J Endod. 2011; 37: 1580-1584
- Resistance to flexural fatigue of Reciproc R25 files under continuous rotation and reciprocating movement.J Endod. 2012; 38: 684-687
- The ability of the Reciproc R25 instrument to reach the full root canal working length without a glide path.Int Endod J. 2013; 46: 993-998
- Canal preparation using only one Ni-Ti rotary instrument: preliminary observations.Int Endod J. 2008; 41: 339-344
- Effects of two nickel-titanium instrument systems, Mtwo versus ProTaper Universal, on root canal geometry assessed by micro–computed tomography.J Endod. 2011; 37: 1412-1416
- A comparison of the minimum canal wall thickness remaining following preparation using two nickel-titanium rotary systems.Int Endod J. 2003; 36: 636-642
- Root canal anatomy of the human permanent teeth.Oral Surg Oral Med Oral Pathol. 1984; 58: 589-599
- A comparison of canal preparations in straight and curved canals.Oral Surg Oral Med Oral Pathol. 1971; 32: 271-275
- Shaping ability and cleaning effectiveness of two single-file systems in severely curved root canals of extracted teeth: Reciproc and WaveOne versus Mtwo and ProTaper.Int Endod J. 2012; 45: 449-461
- The effect of root canal taper on the irrigant flow: evaluation using an unsteady computational fluid dynamics model.Int Endod J. 2010; 43: 909-916
- Effect of apical size and taper on volume of irrigant delivered at working length with apical negative pressure at different root curvatures.J Endod. 2013; 39: 119-124
- Histological evaluation of the effectiveness of increased apical enlargement for cleaning the apical third of curved canals.Int Endod J. 2010; 43: 988-994
- The effectiveness of increased apical enlargement in reducing intracanal bacteria.J Endod. 2002; 28: 779-783
- Reduction in intracanal bacteria during root canal preparation with and without apical enlargement.Int Endod J. 2002; 35: 437-446
- Success rate of single versus two visit root canal treatment of teeth with apical periodontitis: a randomized controlled trial.J Endod. 2012; 38: 1164-1169
- Effect of different apical preparation sizes on outcome of primary endodontic treatment: a randomized controlled trial.J Endod. 2012; 38: 1309-1315
- The risk of perforation in curved canal: anticurvature filing compared with the stepback technique.Int Endod J. 1987; 20: 33-39
- Assessment of apically extruded debris produced by the single-file ProTaper technique under reciprocating movement.Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010; 110: 390-394
- Apical enlargement according to different pecking times at working length using reciprocating files.J Endod. 2014; 40: 281-284
Published online: August 12, 2014
© 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.