Clinico-statistical study on impacted supernumerary teeth in the anterior region of the upper jaw.

Impacted supernumerary anterior teeth in the upper jaw were clinico-statistically reviewed in 139 patients at our department during the past 7 years. The following results were obtained.1. The incidence was approximately 1.5%. Extraction was performed on 120 (86.3%) of the 139 patients.2. By sex distribution, the patients consisted of 116 males and 23 females. The incidence of impacted supernumerary upper anterior teeth was approximately five times as great in the male patients as in the female patients.3. The ages ranged from 4 to 57 years. Patients of 7 to 10 years accounted for 66.2%(92 cases).4. On examining the number of impacted supernumerary teeth, one was observed in 87 cases (62.6%), one with an erupted supernumerary tooth in 29 (20.9%), and two in 23 (16.5%), respectively. None of the patients had more than three impacted supernumerary teeth.5. The state of impaction was examined in 85 patients (106 teeth) who underwent tooth extraction.In 57 patients with one impacted supernumerary tooth, the tooth was impacted in a normal direction of eruption in 21.1% and in inverted position in 71.9%. In 21 patients with two impacted supernumerary teeth, the direction of impaction was normal+inverted in 28.6% and inverted+inverted in 66.7%. In all seven patients with an erupted supernumerary tooth, the direction of impaction was inverted.On examining distomesially the positions of the impacted supernumerary teeth, impaction occurred between the roots of the right and left upper central incisors in 95.3%. When examined in a vertical direction, the impacted teeth were located inferiorly to the radix of the upper central incisor or at some distance away from the root in 72.6%.6. Cystic formation on the X-ray films were 18 cases (17.0%).7. Incision for tooth extraction was placed from the palatal side in 95 (79.2%) of the 120 cases.8. 10 patients (8.3%) developed postoperative complications but these were all transient and mild.9. Roentgenological diagnosis were carried out intraorally by the bisecting angle and occlusal methods and extraorally by orthopantomography, lateral projection and tomography. In some cases in which the location of impaction was unclear, two to five kinds of imaging techniques were used in combination. At the stage of mixed dentition, tomography was found more useful than lateral projection for assessing the positional relationship of the impacted supernumerary tooth and adjacent teeth.For the treatment of impacted supernumerary upper anterior teeth, it is our plan to first continue careful observation with extraction already in mind and then perform extraction when, taking individual differences of patients into consideration, the patients grow up mentally strong enough to withstand the stress of operation.