The purpose of the present study was to investigate the effect of unerupted maxillary incisors on dentofacial structures comparing a group with unerupted teeth with a group with crowded teeth at Hellman's dental age IIIB. The group with unerupted teeth comprised fifteen girls (mean age: 10.3years) exhibiting the unerupted maxillary incisor. The group with crowded teeth consisted of fifteen girls (mean age: 10.2 years) with class I crowded malocclusion. All of the subjects were evaluated cephalometrically.
The results were obtained as follows.
1) L1 to Mp angle, Overjet and Overbite were significantly smaller in the group with unerupted teeth compared with the group with crowded teeth.
2) The values of ANS-U1e/ANS-Me and ANS-U1e/Me-L1e ratios were shown to be significantly smaller in the group with unerupted teeth than in the group with crowded teeth.
3) The distances between points A and Pr, and between points ANS and Pr were revealed to be significantly smaller in the group with unerupted teeth in comparison with the group with crowded teeth.
The above-mentioned results suggested that the unerupted maxillary incisors were associated with lingual inclination of the lower incisors, smaller height of maxillary alveolar process, and decreased overjet and overbite. These dentofacial anomalies with the unerupted maxillary incisors should be considered with respect to diagnosis, treatment planning and mechanotherapy.