Frequency And Characteristics Of Tooth Agenesis Among Orthodontic Patients In Different Nationalities Of Xining Area

Purpose The objectives of this study were to investigate the prevalence and characteristics of tooth agenesis in a group of patients seeking orthodontic treatment in Xining first people’s hospital of Qinghai province.Methods2,911orthodontic patients (1,863females and1,048males; mean age14.6±3.8years) were selected during the period2007.1-2012.12.The prevalence tooth agenesis was calculated between sex and different ethnic. The characteristics of tooth agenesis were evaluated according to missing teeth number in different groups. The Pearson chi-square test was performed to determine potential differences.Results The prevalence of tooth agenesis was7.7percent for the Qinghai orthodontic patients. Tooth agenesis was found more frequently in females than in males (p<0.05). The ratio is3:2. Han,Hui,Tibetan prevalence rate were7.3%、12.1%、10.0%.This difference was not statistically significant (p>0.05). The number of missing teeth one to two accounted for95.6%. The most commonly missing teeth were the mandibular lateral incisors, In the upper arch, there was higher percentage of missing teeth number. It was symmetrical between left and right. The percentage of missing teeth number in incisor, canine and posterior region had a significant difference between the three groups (p<0.01)Conclusions The prevalence of tooth agenesis was7.7percent for the Qinghai orthodontic patients. The other result of tooth agenesie is similar to the reports. Han, Hui, Tibetan prevalence rates were7.3%,12.1%,10.0%. It still cannot believe that there were no differences between the prevalence due to the limited range of samples. When missing one or two teeth, the number of missing teeth focus on the incisor area, When missing up to two teeth, posterior region had an increased proportion of missing teeth number.