Emergence angles in natural maxillary anterior teeth: 3D geological models

Objectives: To find the geometric values of emergence angles at cementoenamel junction (CEJ) in natural maxillary anterior teeth. Methods: One hundred and forty eight cervical intact extracted natural maxillary anterior teeth (74 central incisors, 59 lateral incisors and 15 canines) were collected for study. After carefully surface cleaning, the teeth were scanned with a 3D scanner to construct 3D models. The emergence angles of cervical CEJ were measured on the zenith of labial, palatal, mesial and distal for each tooth respectively. Two-way ANOVA for multiple comparisons were performed. Results: The mean emergence angles of maxillary anterior teeth at different aspects are: 13.65°±5.42°(labial), 11.99°±4.679°(palatal), 12.37°±4.17°(mesial), 13.47°±5.15°(distal). The mean angles of central incisors are: 15.26°±5.64°(labial), 11.97°±5.10°(palatal), 13.29°±4.61°(mesial), 14.49°±5.27°(distal); lateral incisors are: 12.11°±4.58°(labial), 11.84°±4.52°(palatal), 11.30°±3.59°(mesial), 12.40°±4.83°(distal) and canines are 11.65°±5.25°(labial), 12.70°±4.42°(palatal), 11.96°±3.06°(mesial), 12.54°±5.10°(distal) correspondingly. No statistical significant differences were found among the groups (p > 0.05). Conclusion: The variation of emergence angle at cementoenamel junction in natural maxillary anterior teeth is small ranging from 11 to 16 degrees.