title: Root Canal Morphology of Permanent Mandibular Premolars in Iranian Population: A Systematic Review.
abstract: BACKGROUND
  It is essential for clinicians to have knowledge about root canal configuration, although its morphology varies largely in different ethnicities and even in different individuals within the same ethnic group. The current study reviewed the root canal configuration of root canals in mandibular first and second premolars among Iranian population based on independent epidemiological studies.
  
  
  METHODS
  A comprehensive search was conducted on retrieved articles related to root canal configuration and prevalence of each types of root canal in mandibular premolars based on Vertucci's classification. An electronic search was conducted in Medline, Scopus and Google Scholar from January 1984 to September 2015.
  
  
  RESULTS
  In eleven studies conducted in eight provinces, 1644 mandibular first premolars and 1268 second premolars were investigated. Within mandibular first premolars, 70.9% were Vertucci's type I, followed by 10.4% type III, 7.18% type IV, 5.23% type II and 5.16% type V. In addition, among mandibular second premolars, 82.86% were type I, 6.25 type III, 5.32% type II, 4.27% type IV, and 0.69% type V.
  
  
  CONCLUSIONS
  These results highlight the necessity of searching for additional possible root canals by clinicians. Moreover, these results indicated the ethnical characteristics of Iranian population regarding the morphology of mandibular premolars compared to other populations.
authors.affiliation: Students' Research Office, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran;
authors.forename: Sepanta
authors.initials: S
authors.lastname: Hosseinpour
authors.affiliation: Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran;
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Kharazifard
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Canada;
authors.forename: Akbar
authors.initials: A
authors.lastname: Khayat
authors.affiliation: Department of Endodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mandana
authors.initials: M
authors.lastname: Naseri
keywords: Anatomy; Iranian; Mandibular Premolar; Review; Root Canal