title: Evaluation of radicular dentin thickness of danger zone in mandibular first molars.
abstract: OBJECTIVE
  Better understanding of the furcation anatomy may serve to decrease the risk of root perforation. The purpose of this study was to measure the thickness of root walls in the danger zone in mandibular first molars.
  
  
  METHODS
  The roots of 53 extracted human mandibular first molars were sectioned in the horizontal plane 4 mm below the orifice of the mesial and distal root canals. For each cut surface buccal, lingual, mesial, and distal thickness of the root wall was measured. Mean values of the thickness at each location were calculated and compared by ANOVA and t-test.
  
  
  RESULTS
  The results showed that the mean thickness in the distal portion of the mesial root was smaller in comparison to all other portions of the roots (P<0.05) and this difference was statistically significant except for the mesial portion of the distal root (P=0.463). The mean thickness of radicular dentin at the distal aspect of mesial roots was 1.2 millimeter.
  
  
  CONCLUSIONS
  Our study suggests that knowledge of the root dentin thickness in the danger zone is essential for preventing endodontic mishaps leading to failure.
authors: Assistant Professor, Department of Endodontics, School of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors: M
authors: M
authors: Tabrizizadeh
authors: J
authors: J
authors: Reuben
authors: M
authors: M
authors: Khalesi
authors: M
authors: M
authors: Mousavinasab
authors: Mk Ghane
authors: MG
authors: Ezabadi