Meta-analysis of congenitally missing teeth in the permanent dentition: Prevalence, variations across ethnicities, regions and time.
BACKGROUND
Congenitally missing teeth (CMT) are of concern to many fields of dentistry. Only a few reviews have been published in this regard.


OBJECTIVE
The aim was to analyze the literature on CMT in the permanent dentition, excluding the third molars, and to identify potential links with ethnicity, geographical regions, and time.


METHODS
A total of 118 reports on CMT were collected by two authors by interrogating databases. Sample homogeneity, publication bias, publication year (in Caucasian and Mongoloid samples, and in general), ethnicities, and geography of CMT prevalence were statistically analyzed using a Q-test, Egger regression, linear regression, a Spearman coefficient, Kruskal-Wallis, a Dunn post-hoc (α = 0.05), and a Mann-Whitney U test (α = 0.0125, α = 0.0071).


RESULTS
The mean CMT prevalence was 6.53% ± 3.33%. There were significant geographic differences in CMT rates (P = 0.0001, Kruskal-Wallis) and between ethnicities (P = 0.0002, Kruskal-Wallis). According to the Mann-Whitney U test (α = 0.0071), eastern Asians (P = 0.0008) and Europeans (marginally significant, P = 0.0128) showed an elevated prevalence, while Western Asians (P = 0.0001) and Americans (marginally significant, P = 0.0292) had lower prevalence rates. Compared with other ethnicities, Mongoloids showed higher prevalence (P = 0.0009) while Asian Caucasians showed lower rates (P = 0.0005, Mann-Whitney U, α = 0.0125). The year of publication was not significantly correlated with any of the subsamples studied (P > 0.3, linear regression).


CONCLUSIONS
Clinicians should be vigilant in the assessment of CMT in Mongoloids. No increase of this condition was detected during the last century.
Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Dental Anatomy and Morphology, Dental Branch, Islamic Azad University, Tehran, Iran. Electronic address: v_rakhshan@dentaliau.ac.ir.
Vahid
V
Rakhshan
Tehran, Iran.
Hamid
H
Rakhshan
D000848:Anodontia / Q000453:epidemiology* / Q000208:ethnology; D044466:Asian People / Q000208:ethnology / Q000706:statistics & numerical data; D044383:Black People / Q000208:ethnology / Q000706:statistics & numerical data; D014943:Global Health / Q000208:ethnology / Q000706:statistics & numerical data*; D006801:Humans; D015995:Prevalence; D044469:Racial Groups / Q000208:ethnology / Q000706:statistics & numerical data*; D044465:White People / Q000208:ethnology / Q000706:statistics & numerical data
Congenitally missing teeth (hypodontia); Continents; Ethnicity; Permanent dentition; Prevalence; Time populations