Korean J Oral Maxillofac Radiol.  2007 Jun;37(2):103-110.

Evaluation of danger zone in mesial root of mandibular first molar by cone beam computed tomography (CBCT)

• Chang YR
• Choi YS
• Choi GW
• Park SH

Abstract

PURPOSE: To examine the danger zone of mesial root of mandibular first molar of patient without extraction using CBCT(cone -beam computed tomography) to avoid the risk of root perforation.
MATERIALS AND METHODS
20 mandibular first molars without caries and restorations were collected. CT images were obtained by CBCT(PSR9000N TM, Asahi Roentgen Co., Japan), reformed and analyzed by V-work 5.0 (CyberMed Inc., Korea). Distance between canal orifice and furcation was measured. In cross sectional images at 3, 4 and 5 mm below the canal orifice, distal wall thickness of mesiobuccal canal (MB-D), distal wall thickness of mesiolingual canal (ML-D), distal wall thickness of central part (C-D), mesial wall thickness of mesiobuccal canal (MB-M) and mesial wall thickness of mesiolingual canal (ML-M) were measured.
RESULTS
The mean distance between the canal orifice and the furcation of the roots is 2.40 mm. Distal wall is found to be thinner than mesial wall. Mean dentinal wall thickness of distal wall is about 1 mm. The wall thickness is thinner as the distance from the canal orifice is farther. But significant differences are not noted between 4 mm and 5 mm in MB-D and C-D. MB-D is thinner than ML-D although the differences is not significant.
CONCLUSION
The present study confirmed the anatomical weakness of distal surface of the coronal part of the mesial roots of mandibular first molar by CBCT and provided an anatomical guide line of wall thickness during endodontic treatment.

Keyword

Mandibular First Molar; Danger Zone; Dentinal Wall Thickness; Tomography, Cone Beam Computed

MeSH Terms

Cone-Beam Computed Tomography*
Dentin
Humans
Molar*