title: Correlation of root dentin thickness and length of roots in mesial roots of mandibular molars.
abstract: BACKGROUND
  The purpose of this study was to analyze the relation of tooth length and distal wall thickness of mesial roots in mandibular molars at different locations (ie, 2 mm below the furcation and at the junction between the middle and apical third).
  
  
  METHODS
  Forty-five mandibular first molars were taken, and the length of each tooth was measured. Then, specimens were divided into three groups according to their length: group I-long (24.2 mm ± 1.8), group II-medium (21 mm ± 1.5) and group III-short (16.8 mm ± 1.8). mesial root of each marked at two levels - at 2 mm below the furcation as well as at junction of apical and middle third of roots. The minimum thickness of the distal root dentine associated with the buccal and lingual canals of the mesial roots was measured, The distance between the buccal and lingual canals and the depth of concavity in the distal surface of the mesial roots were also measured.
  
  
  RESULTS
  Statistical analysis was performed by using analysis of variance and the Student-Newman-Keuls test. The minimum thickness of the distal wall of the mesiobuccal canal was significantly different (P < .001) between groups 1 (long) and 3 (short).
  
  
  CONCLUSIONS
  Distal wall thickness of the mesiobuccal root and distal concavity of the mesial root of mandibular first molars were found to be thinner in longer teeth compared with shorter teeth.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India. Electronic address: shwetaCdwivedi@gmail.com.
authors.forename: Shweta
authors.initials: S
authors.lastname: Dwivedi
authors.affiliation: Department of Oral and Maxillofacial Surgery, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors.forename: Chandra Dhar
authors.initials: CD
authors.lastname: Dwivedi
authors.affiliation: Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
authors.forename: Neelam
authors.initials: N
authors.lastname: Mittal
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology*; D006801:Humans; D008334:Mandible; D008963:Molar / Q000033:anatomy & histology*; D009811:Odontometry / Q000379:methods; D019227:Tooth Apex / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology*
keywords: Mandibular molars; mesial roots; stereomicroscope