title: Root-crown ratio in permanent dentition using panoramic radiography in a selected Iranian population.
abstract: BACKGROUND
  Determining the crown-root ratio is crucial in many dental clinical decisions. There are no reliable data presented for Iranian population.
  
  
  OBJECTIVE
  The aim of this study was to assess the root-crown ratio of permanent teeth with regards to the relationship of gender and jaw type using panoramic radiographs. The reliability of method was also assessed.
  
  
  METHODS
  The crown and root lengths of teeth were measured by a digital caliper on panoramic radiographs of 185 individuals except for the third molars. A total of 1994 teeth was studied and 50.8% of the teeth belonged to males and 49.2% belonged to females. The modified Lind method was applied.
  
  
  RESULTS
  The highest mean root-crown ratios in both arches of both genders were obtained in the second premolars, followed by the first premolars and canines. In both genders, the lowest root-crown ratios were found in the maxillary central incisors. In male patients, the mean root-crown ratio was higher (p= 0.003) than that of females. Using Bland-Altman analysis, a non-significant difference of 0.006 (95% CI: -0.012-0.024) and 0.0002 (95% CI: -0.011-0.011) were found for intra-observer and inter-observer agreement, respectively.
  
  
  CONCLUSIONS
  Assessment of the root-crown ratio in permanent dentition could be performed on panoramic radiographs with acceptable reproducibility in an Iranian Population. Considering observed differences, our findings suggest that for the accurate assessment, this ratio must be calculated for male and female patients and also for the upper and lower jaws, separately.
authors.affiliation: Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Sina
authors.initials: S
authors.lastname: Haghanifar
authors.affiliation: Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Moudi
authors.affiliation: General Dental Practitioner, Private Practice, Babol, Iran.
authors.forename: Shirin
authors.initials: S
authors.lastname: Abbasi
authors.affiliation: Noncommunicable Pediatric Diseases Research Center, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Bijani
authors.affiliation: Dental Materials Research Center, School of Dentistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Arash
authors.initials: A
authors.lastname: Poorsattar Bejeh Mir
authors.affiliation: General Dental Practitioner, Private Practice, Babol, Iran.
authors.forename: Nafiseh
authors.initials: N
authors.lastname: Ghasemi
keywords: Anatomy; Panoramic radiography; Root-Crown Ratio