Measurement And Analysis Of The Gingival And Bone Tissue Of The Maxillary Anterior Teeth Using CBCT

Object: The aesthetic area of maxillary anterior teeth of 95 healthy adults was scanned by cone beam computed tomography（CBCT）.After 3D reconstruction,the relative anatomical structures of soft and hard tissues in this area were measured and analyzed to study the gingival thickness in aesthetic area of maxillary anterior teeth,the basic bone situation of the maxillary anterior teeth,the relationship between the position of maxillary anterior teeth and the labial and palate position of the alveolar bone,and the correlation between the above measured results.Besides,the feasibility of measuring gingival thickness by CBCT was analyzed too.This study will provide a certain reference for aesthetic implant restoration of maxillary anterior teeth.Method: 95 healthy adults（mean age 33.79±10.65 years）were selected according to certain inclusion criteria.CBCT scanning was performed by indirect imaging method.The thickness of labial gingiva,the thickness of labial and palatal bone wall,the thickness and height of the alveolar bone,the lip and tongue inclination of anterior teeth and the gray value of interdental alveolar bone in anterior teeth were measured after 3D reconstruction.The data were analyzed by using SPSS20.0software package and the test level was α=0.05 on both sides.Results: 1.There was no statistical difference in soft and hard tissue of maxillary anterior teeth between males and females among 95 healthy adults,and there was no statistical difference between left and right teeth of the same name,but there was statistical difference among different tooth positions,which should be paidmore attention to in the process of anterior tooth implantation.2.The gingival thickness of the labial side of the maxillary anterior teeth in 95 healthy adults was less than 1mm,and the average thickness was（0.85±0.10）mm^0.91±0.12mm,which belongs to the thin gingival biotype.For maxillary central incisor,lateral incisor and canine,the ratio of the thickness of the labial gingiva greater than 1mm was only 18.4%,10.5% and 11.6%,respectively.3.The average thickness of the labial wall of maxillary anterior teeth in 95 healthy adults ranged from0.81±0.20 mm to 1.06±0.23 mm.The ratio of the thickness of labial wall of maxillary central incisor,lateral incisor and canine was 60%,23% and 9.5%,respectively;the average thickness of palatine wall was between 2.42±0.71 mm to3.47±0.98 mm.The ratio of palatal wall thickness of central incisor,lateral incisor and canine was 91.6%,73.7%and 96.8% respectively.4.The average thickness of maxillary anterior alveolar bone in 95 healthy adults ranged from7.63±0.96 mm to 10.01±1.03 mm,and the average height was between20.29±3.05 mm and 21.68±2.40 mm,which could meet the minimum requirements of implants.5.The angle between the long axis of teeth and alveolar crest of 95 healthy adults in maxillary anterior teeth ranged from14.01±4.96°to 18.26± 5.55°.6.The multiple correlation analysis showed that there was a positive correlation between the thickness of palatal bone wall and alveolar bone thickness and the angle value between the long axis of the teeth and the alveolar crest.Conclusions: 1.Most of the labial gingival thickness of the maxillary anterior teeth in 95 healthy adults were less than 1 mm,belonging to the thin gingiva biological type.Compared with the patients with thick gingiva biotype,gingival retraction and alveolar bone resorption were more likely to occur,which had an important influence on aesthetic implant and shoud be paid more attention to.2.Most of the thickness of the labial bone wall of maxillary anterior teeth in 95 healthy adults was less than 1 mm,and the vast majority（73.68⁹6.84%）of the thickness of palatal bone wall was more than 2 mm.It was easy to lead to the thin bone wall of the labial side of implant,so it was difficult to obtain and maintain a good aesthetic and long-term effect.3.The thickness and height of maxillary anterior alveolar bone in 95 healthy adults could basically meet the minimum requirements of implants.4.There was an angle（14.01±4.96°¹8.26±5.55°）between the long axis of maxillary anterior teeth and the long axis of alveolar bone in 95 healthy adults.The obliquity angle of lip and tongue of anterior teeth was different among different tooth positions,and the thickness of palatal bone wall and alveolar bone were positively correlated with this angle.