title: The location of the cementodentinal junction in single-rooted mandibular first premolars from Egyptian and Saudi patients: a histological study.
abstract: OBJECTIVE
  To determine the location of the cementodentinal junction (CDJ) in mandibular first premolars from Egyptian and Saudi patients.
  
  
  METHODS
  One hundred and twenty-two extracted single-rooted mandibular first premolars (68 Egyptian; 54 Saudi) were examined histologically. Half of the teeth were fixed, decalcified, embedded in paraffin, mesio-distally sectioned and stained with H&E, whilst the other half were ground with a stone prior to microscopic evaluation. Measurements of the location of the CDJ were made parallel to the long axis of the teeth from the external surface of the root apex on the mesial and distal sides of the canal. Measurements were statistically analysed using two-way anova of repeated-measure design.
  
  
  RESULTS
  The CDJ in Egyptian sections ranged from 0 to 2.0 mm (mean +/- SD = 0.9 +/- 0.4 mm) on the mesial side of the canal and from 0.2 to 2.5 mm (mean +/- SD = 1.0 +/- 0.5 mm) on the distal aspect. In the Saudi sample, the CDJ ranged from 0.5 to 1.2 mm (mean +/- SD = 0.8 +/- 0.3 mm) on the mesial side and from 0.6 to 0.9 mm (mean +/- SD = 0.7 +/- 0.4 mm) on the distal side. The mesial and distal differences between Egyptian and Saudi premolars on the mesial and distal surface were statistically significant (P < 0.001).
  
  
  CONCLUSIONS
  The location of the CDJ varied between the Egyptian and Saudi mandibular first premolars, indicating that this junction is not a fixed point in populations of different countries.
authors.affiliation: Department of Restorative Dental Sciences, Endodontic Division, College of Dentistry, King Saud University, Kingdom of Saudi Arabia. aysaad@ksu.edu.sa
authors.forename: A Y
authors.initials: AY
authors.lastname: Saad
authors.forename: A S
authors.initials: AS
authors.lastname: Al-Yahya
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001641:Bicuspid / Q000033:anatomy & histology*; D003739:Dental Cementum / Q000033:anatomy & histology*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology*; D004534:Egypt; D005260:Female; D006801:Humans; D008297:Male; D012529:Saudi Arabia; D019227:Tooth Apex / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology*