title: The prevalence and distribution pattern of hypodontia among orthodontic patients in Southern Iran.
abstract: OBJECTIVE
  To evaluate the pattern and prevalence of hypodontia and its association with different malocclusions among orthodontic patients in southern Iran.
  
  
  METHODS
  In this study, a total of 494 records of orthodontic patients (162 males, 332 females) were evaluated. To investigate percent of hypodontia pertinent information of patients was evaluated. Chi-square and Fisher's exact tests were used for statistical analysis.
  
  
  RESULTS
  The prevalence of tooth agenesis was 7.66%. Thirty-eight patients were found to have at least one tooth missing. Number of patients having hypodontia was the most in class III patients, whereas the number of missing teeth was more in class II sample. However, it was not statistically significant (P = 0.569). Upper lateral incisor (27.95%), lower second premolar (21.51%), and upper first premolar (12.9%) were respectively the most frequently absent teeth. There was not statistically significant difference between sexes (P = 0.580). Hypodontia observed to be more bilaterally, in the upper arch and in the left side.
  
  
  CONCLUSIONS
  The pattern and prevalence of hypodontia is different among races and ethnic groups. In our study population, hypodontia was found to be 7.66%. Higher prevalence of hypodontia in the maxillary arch and in class III patients may be considered as an etiologic factor.
authors: Orthodontic Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Zohreh
authors: Z
authors: Hedayati
authors: Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Yunes Nazari
authors: YN
authors: Dashlibrun
keywords: Hypodontia; malocclusion; orthodontics; tooth agenesis