An Epidemiological Analysis Of Impacted Teeth In Orthodontic Patients And An Study Of Elements Of Forced Eruption About Inversely Impacted Maxillary Central Incisor

Objective:To make an epidemiological and descriptive study of the basic characteristics of patients who associated with malocclusion with impacted teeth,in order to further enrich prevalence data of impacted teeth, and take advantage of onventional cephalometric radiographs and panoramic radiographs to analysis the factors that affect the duration of forced eruption of the inversely impacted maxillary central incisor,and analyzed and compared different traction methods on the basis of the clinical to guide clinical practice. Methods:To collect the orthpantomography and lateral skull radiographs of 3757 patient in the Dept. of Orthodontic of the Affiliated Hospital of Qingdao University from Jan. 1 2010 to Dec.1 2014(except in patients with primary dentition).259 patients were diagnosed as impacted teeth(excluding supernumerary teeth and third molars),then take the variables of gender, age, quantity, location into account.Measure cephalometric radiographs of 26 patients with inversely maxillary central incisor, analyze the relationship between the factors and the duration of forced eruption of the inversely maxillary central incisor.15 inversely impacted upper central incisors with successfully guided were selected.The applyied conditions,traction time and the success rate of the three groups was studied and analyzed. Results:The prevalence rate of impacted teeth in patients who associated with malocclusion was 6.89%.The male patients were more frequently sufferred than female patients,but there was no significant differencet.Among these impacted teeth,the highest proportion is maxillary canine,followed by the maxillary central incisor.The number of impacted teeth was mostly single, accounting for 71.04%.Patients with impacted teeth occur in mixed dentition period, there was a statistically significant difference.The results indicated that there was a positive correlation between the duration of forced eruption and inverted angle of impacted tooth.And there was a positive correlation of the duration of forced eruption with the age. In addition, a direct correlation of the duration of forced eruption with the curvature of the root, which with curved root was needed more treatment time.The success rate among the reverse pull headgear and homemade appliance group objects was 100% compared with 60% among the intermaxillary traction ones,but the difference was not significant(P> 0.05).Compared with the other two groups,the reverse pull headgear objects showed significant increase in the duration of treating the impacted upper central incisors(P<0.05).Conclusions:1. The prevalence rate of impacted teeth of in orthodontic patients,especially the maxillary canine and maxillary central incisors,which needs patients’ and orthodontists’ attention.2. The patient’s age,inverted angle of impacted tooth and the curvature of the root can be provided as important predictors of the duration of the forced eruption.3. Compared with intermaxillary traction, reverse pull headgear traction and homemade appliance traction more suitable for artificial eruption of impacted teeth.