A Study Of Maxillary Anterior Teeth In Chinese Individuals Evaluated By Cone-Beam Computed Tomography

Purpose:This study analyzed the location and angulation of the maxillary anterior teeth with reference to the alveolus, providing some referential data for clinicians to achieve the best results for implant placement in the esthetic zone.Materials and Methods:A large quantity of CBCT images from Shandong University Stomatological Hospital were reviewed and screened.150maxillary images evenly divided between male and female (between the ages of19and48years at the time of CBCT scan) were selected strictly according to the defined inclusive criteria. The maxillary anterior teeth were pooled into the following three groups for men and women each:upper canines, upper lateral incisors, upper central incisors. Four linear aspects were measured:the bone thickness of their alveolar bone crest, the bone thickness of their alveolar bone, and the thickness of the palatal and labial bone at their apical level. Then the long axes of each qualified tooth and its corresponding alveolar process were drawn and the angles formed by them were measured. The data were analyzed by SPSS.Results:The mean thickness of the alveolar bone crest of maxillary center incisors, lateral incisors and canines for male subjects are8.06mm,7.58mm and9.58mm; as for females, they are7.64mm,6.99mm and8.64mm, respectively.The mean thickness of the alveolar bone of maxillary center incisors, lateral incisors and canines for male subjects are9.89mm,8.69mm and11.87mm; as for females, they are8.27mm,7.27mm and10.26mm, respectively.The thickness of the labial bone at the apical level of maxillary center incisors, lateral incisors and canines ranged from0mm to5.69mm. A thin facial bone wall (<2.0mm) at the apical level was quite frequent in central incisors (69.33%in males,81.33%in females), lateral incisors (60%in males,78%in females) and canines (62%in males,64.67%in females).The mean thickness of the palatal bone at the apical level of maxillary center incisors, lateral incisors and canines are8.14mm,7.01mm and10.29mm in males, and6.92mm,7.01mm and9.07mm in females.The long axes of all the maxillary anterior teeth incline to the palatal side of the alveolar process. The internal angle (a) formed by the long axis of the maxillary central incisors and the long axis of the alveolar bone was16.22degrees (range,2.50～28.80degrees) for male subjects and15.20degrees (range,2.20～27.20degrees) for female subjects, respectively. The internal angle (a) of the maxillary lateral incisors was17.50degrees (range,3.80～29.50degrees) for male subjects and15.59degrees (range,4.10～33.30degrees) for female subjects, respectively. The internal angle (a) of the maxillary canines was16.27degrees (range,1.00～31.50degrees) for male subjects and15.01degrees (range,3.50～27.40degrees) for female subjects.There were differences between males and females in the linear data of three groups and the angulation of maxillary lateral incisors and maxillary canines.Conclusion:For implant placement, careful preoperative analysis and evaluation with CBCT may be beneficial to avoid the risk factors and to achieve high predictability of success in the esthetic region.