| Objective To evaluate the bone changes and its influencing factors after dental implant in the maxillary anterior area by CBCT data.In order to help clinician determine the implant site,improve the restoration,and meeting the expectations of dental implant patients.Methods A total of 34 patients missing maxillary anterior teeth requiring dental implant from March 2018 to June 2022 in the Department of Stomatology,LiTongDe Hospital,Zhejiang Province were collected,with 40 implants placed.All patients accept dental implant with GBR.Cone-Beam Computed Tomography(CBCT)was taken before operation(T0),immediately(T1)after and 6 months(T2)after operation,and the implant retention rate was counted at 6 months after the operation.The digital software 3D Ondemand was used to measure the inclination of the alveolar process in the implant area before the operation,the inclination of the implant,and the thickness of the labial and palatal bone plates at the four sites of 0 mm(Sl),3 mm(S2),6 mm(S3)and 9 mm(S4)under the implant platform and the height of the labial bone immediately and 6 months after the operation.Perform statistical analysis of the data.Results 1.CBCT scans showed that 2 implants bone height loss at the labial and palate sides was greater than 4mm at T2 respectively,and the other implants had good bone osseointegration.Therefore,the retention rate of the implants was 95%(38/40)at T2.2.The mean inclination of the alveolar process was 125.4 ± 7.4 °,and the mean inclination of the implant was 112.8 ± 7.9°.The mean angle between the axis of alveolar process and implant was 12.5± 4.7°.3.There was bone loss 6 months after implantation compared to immediately after surgery.the bone thickness loss at sites S1、S2、S3、S4 of labial was 1.15±0.86mm,0.80±0.82mm,0.50± 0.61mm and 0.24 ± 0.53mm respectively,of palatal was 0.72 ± 0.41mm,0.40 ± 0.48 mm,0.20 ±0.36mm and 0.08 ± 0.34mm respectively;The bone height loss was 0.99± 0.62mm.4.In the vertical direction,there were significant differences in bone thickness loss between S1 and S3,between S2 and S4,and between S1 and S4(p<0.05);In the horizontal direction,there were significant differences in bone thickness loss of labial and palatal at the same side(p<0.05).The bone loss rate at S1 site of palatal side was greater than labial side,while at the S2,S3,and S4 sites,the labial side was greater than the palatal side.5.There is a positive correlation of the bone thickness between immediately after and 6 months after operation at S1,S2,S3 and S4 sites(p<0.05);There was a positive correlation between the bone thickness immediately after operation and the bone loss at S1 site(p<0.05).There was no correlation between bone thickness at S1 site immediately after operation and bone height loss(p>0.05).There was no correlation between bone thickness immediately after operation and bone thickness loss at S2,S3,S4 sites(p>0.05).6.There was no correlation between the inclination of alveolar process,the inclination of implant and the bone thickness loss at S1,S2,S3 and S4 sides of labial and palatal(p>0.05);The angle between the axis of the alveolar process and the axis of the implant was negatively correlated with the bone loss at palatal S1 site,r<0,p<0.05.Conclusion 1.The bone augmentation effect after dental implant simultaneous with GBR in maxillary anterior within 6 months was stable.2.There is a certain degree of bone loss around the implant after dental implant in the maxillary anterior area.In the vertical direction,bone loss gradually decreases from the neck to the apical direction,and in the horizontal direction,there are differences in bone thickness loss between the labial and palatal sides at the same horizontal site.3.At all sites,the initial bone thickness has an impact on the remaining bone thickness at 6 months after dental implant in maxillary anterior.At implant neck,initial bone thickness has an impact on the bone thickness loss,while has no effect on the bone height loss.Therefore,it is necessary to ensure that the initial bone thickness of the implant neck is at least 2.5～3mm on the labial side and at least 1.5～2mm on the palatal side.4.The inclination of the alveolar process and the implant have no effect on bone thickness loss around the implant,while the angle between the long axis of the alveolar process and the long axis of the implant has an impact on the bone thickness loss at the palatal side of the implant neck,the larger the angle,the less the bone loss.Therefore,when implant was tilted towards the palatal side at maxillary anterior area,it is necessary to ensure that 1.5～2mm bone thickness left in the palatal side of implant neck. |
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