title: Systematic review and meta-analysis of congenitally missing permanent dentition: Sex dimorphism, occurrence patterns, associated factors and biasing factors.
abstract: OBJECTIVE
  We aimed to summarize/analyze, comprehensively and for the first time, the literature on the prevalence of congenitally missing teeth (CMT) in males and females and the CMT pattern, taking various associated and biasing factors into account.
  
  
  METHODS
  A search was performed independently by two authors during September 2012 till June 2013 to find all the available literature regarding CMT-associated factors and patterns comprising sex dimorphism, arches, anterior/posterior regions, unilateral/bilateral patterns, and involved teeth. The data were statistically analyzed.
  
  
  RESULTS
  Seventy-four studies were included. The mean CMT prevalence was 6.42±2.76% in males and 7.55±2.67% in females. Overall, CMT is more prevalent in females but only in epidemiological samples, and not in orthodontic or dental patients. Enrolling orthodontic/dental patients might increase the observed CMT in boys and/or reduce it in girls. Gender dimorphism was not affected by any of the factors: time, regions, or the biasing factors. There is not a significant predominance of maxillary or mandibular involvement, although the anterior segment is more likely to be affected.
  
  
  CONCLUSIONS
  CMT is more common in girls and in the anterior segment, regardless of the date of publication. Contrary to the commonly held belief regarding more CMT prevalence in female orthodontic patients, it was shown that in dental/orthodontic patients, CMT prevalence is higher in boys.
authors: Department of dental anatomy and morphology, dental school, Azad university, Tehran, Iran. Electronic address: vahid.rakhshan@gmail.com.
authors: Vahid
authors: V
authors: Rakhshan
authors: Tehran, Iran.
authors: Aghdas
authors: A
authors: Rakhshan
mesh_terms: D000848:Anodontia / Q000453:epidemiology* / Q000209:etiology; D015982:Bias; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012727:Sex Characteristics
keywords: Biasing factors; Congenital missing teeth; Hypodontia; Occurrence pattern; Permanent dentition; Prevalence; Risk factors; Sex dimorphism