Anthropometric Analysis Of The Crown Of Anterior Arch

Part I The measurement accuracy of Plaster Models% CBCT Models and Digital ModeslObjectives:This study aimed to compare the measurement accuracy of Plaster Models、CBCT Models and Digital Models.Methods:A total of 66 teenager orthodontic patients (32 males,34 females; aged 11-14)treated in our hospital were enrolled in the research. Researchers measured the clinical crown length and width of the three kinds models. The length and width of the clinical crown of the upper anteriors were measured, which server as the reference to compare the accuracy of the three kinds of Models.Results:1. The length and width of clinic crown of the digital models was not showed significant difference with anthropological measuring.2. The length and width of clinic crown of the CBCT models was showed difference with the somatometry of upper anteriors.3. The width measurement of clinic crown of plaster casts was brought out significant difference, nevertheless, there was no difference in length.Conclusions:The measurement accuracy of Digital Models was better than Plaster Models and CBCT Models.Part II The observation of morphological characteristics of anteriorsObjectives:This study aimed to observation of anterior morphological characteristics of orthodontic candidates.Methods:66 teenager orthodontic patients (32 males,34 females; aged 11-14) accepted orthodontic treatment were enrolled in the research. The Digital Models and Plaster Models of patients were built and measured the length, width and thickness of anterior teeth. In addition, the correlation of the thickness of upper anteriors with skeletal craniofacial pattern was evaluated.Results:1. The Bolton’s ratio showed significant difference between Han nationality and Caucasion groups(P<0.05).2. The mesiodistal width of maxillary lateral incisor and mandibular central incisor played an important part in Bolton’s ratio discrepancies.3. The thickness of maxillary lateral incisor also displayed a marked difference.4. The mesiodistal width of upper lateral incisors and lower central incisors in right-left quadrant had more discrepaning. Fathermore, the clinical crown length of canine in different side was shown significant diversity.5. The result is that there is a moderate correlation between ∠SNA and upper anterior teeth thickness. There is a low correlation between ∠SNB and upper anterior teeth thickness. There is a moderate correlation between ∠ANB and maxillary lateral incisor’s thickness and a low correlation between ∠ANB and maxillary central incisor and canine’s thickness.6. There is a low correlation between MP-FH/NBa-PtGn and the thickness of the anteriors.Conclusion The size of anterior teeth in Mongoloid teenager orthodontics patients showed ethnic group differences and some regularities, which can provide clinical reference for orthodontic treatment.