Dental crowding: the role of genetics and tooth wear.
OBJECTIVE
To evaluate the role of genetics and tooth wear in the etiology of dental crowding through the analysis of a split indigenous Amazon population.


METHODS
Dental crowding prevalence (n  =  117), tooth wear (n  =  117), and inbreeding coefficient (n  =  288) were compared for both villages. A biometric investigation was performed by dental cast analysis of 55 individuals with no tooth loss. Mann-Whitney statistics, independent t-tests, and Fisher exact tests were used at P < .05.


RESULTS
A high coefficient of inbreeding was confirmed in the resultant village (F  =  0.25, P < .001). Tooth wear was not significantly different (P  =  .99), while a significantly higher prevalence of dental crowding was confirmed in the original village (PR  =  6.67, P  =  0.02). Forty dental arches (n  =  20) were examined in the new group, and only one (2.5%) had a dental crowding ≥ 5 mm. In the original villages, we found 20 arches (28.6%) with dental crowding. No difference was observed for tooth size, while larger dental arch dimensions explained a lower level of dental crowding in the resultant village.


CONCLUSIONS
Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on dental crowding and emphasize the role of heredity, exacerbated through inbreeding, in the etiology of this malocclusion.
Department of Orthodontics, Federal University of Pará, Faculty of Dentistry, Belém, Brazil. davidnormando@hotmail.com
David
D
Normando
Marco A O
MA
Almeida
Cátia C A
CC
Quintão
D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D003241:Consanguinity; D003724:Dental Arch; D004032:Diet / Q000208:ethnology*; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000208:ethnology / Q000209:etiology* / Q000235:genetics; D044382:Population Groups; D015995:Prevalence; D018709:Statistics, Nonparametric; D057085:Tooth Wear