Abstract: Objective: To investigate the alveolar bone thickness around apex of central incisor of early youth, and to analyze the correlation with cephalometric measurement of hard tissue. Methods: To assess 42 malocclusion pations who were accordance with the inclusion criteria with cone-beam CT (CBCT), and to measure the thickness of alveolar bone around apex of the 168 central incisors with MIMICS 10.0 software. To do the cephalometric measurement of the 42 pations with CBCT three-dimensional and lateral cephalogram two-dimensional measurements, and the application of SPSS 21.0 statistical software was for the analysis of the correlationship between the thickness of alveolar bone and the results of cephalometric measurement. Results: The thickness of the labial Alveolar bone around apex of the upper central incisor of early youth is positively associated with the protrusion of the upper central insicor, and is negatively correlated with SNA. The situation of the palatal thickness is as opposed to the labial thickness. The thickness of the labial and lingual Alveolar bone around apex of the lower central incisor is negatively correlated with SN-MP.The labial thickness of the lower central incisor is positively associated with ANB and the protrusion of the lower central insicor, and the situation of the palatal thickness is as opposed to the labial thickness. Conclusion: Some cephalometric indexes of hard tissue are related to the Alveolar bone thickness around apex of central incisor of early youth, which has the clinical reference value.

Key words: Early youth, Central incisor, Alveolar bone, Cone-beam CT