Study on the relationship between the third molar and malocclusion

Objective To study the relationship between the third molar and malocclusion. Methods It was studied panoramic radiograph,cephalogram and record model of 350 patients (male 156, female194) from the orthodontic whose ages were 12～18 yearsdd. Results There was significant difference between the congenitally missing M3 and the crowding(P0.05). And the crowding was the most in malocclusions. There was significant difference between the congenitally missing M3 and the spacing (P0.05). There was no significant difference between the congenitally missing M3 and every skeletal classification(P0.05). But the patients of class Ⅲ were more congenitally missing upper M3. The patients of class Ⅱ were more congenitally missing lower M3. The ratio of classⅠ、Ⅱ、Ⅲ was in 58.3%、26.6%、15.1%. Conclusion The congenitally missing M3 was more in the spacing malocclusion than the other malocclusion. The crowding malocclusion was more in presence M3 than the congenitally missing M3. There were correction between class Ⅱ/Ⅲ and congenitally missing M3 in lower/upper.