Transcrestal Sinus Floor Elevation With Simultaneous Placement Of Dental Implants In Severely Atrophied Posterior Maxilla:Radiographic Evaluation Based On Cone Beam CT

Objective : Study the changes of three-dimensional bone mass in the sinus after adopting the technology of osteotome sinus floor elevation with simultaneous placement of dental implants in severely atrophic maxilla,and to analyze the changing regularity and influencing factors.Methods: From January 2018 to August 2019,18 Volunteers who met the inclusion criteria were collected from patients with maxillary posterior tooth loss treated in the department of stomatology,the fourth affiliated hospital of nanchang university.The same surgeon performed the osteotome sinus floor elevation with simultaneous placement of 37 dental implants through the alveolar crest approach,PRF membrane and bone substitute were placed in the maxillary sinus and locking-taper implants were implanted at the same time,then the periosteal flap was tightly sutured after covering a collagen membrane around the alveolar crest.CBCT images were taken for all the selected patients before implantation(T0),on the day after surgery(T1)and 6 months after surgery(T2).CS 3D Imaging software was used to process the images,then the following data was measured:(1)Residual bone height,RBH;(2)Maxillary sinus width,SW: SW1 was meansured at the top of the implant,and SW2 was meansured at the level of 10 mm from the alveolar crest;(3)Implant protrusion length,IPL;(4)Sinus lift height,SLH;(5)Bone height apically,BHA;(6)Graft resorption,GR.SPSS24.0 statistical software was used for statistical description and analysis,the effects of RBH?SW and IPL on SLH and GR at 6 months after surgery were analyzed.Results:(1)Six months after the surgery,one implant failed and the implant survival rate was 97.3%.(2)Preoperative RBH was 2.80±0.67 mm;SW1 was 12.08±2.48 mm,SW2 was 15.87±2.92 mm;IPL immediately after the operation was 3.63±0.99 mm.RBH changed to 7.89±1.70 mm 6 months after surgery,increased 5.09 mm.SLH and BHA decreased from 6.51±1.36 mm and 3.32±1.21 mm immediately after surgery to 4.94±1.64 mm and 1.56±1.45 mm 6 months after surgery.(3)There was no significant difference in the elevation of maxillary sinus floor(SLH-T2)and GR in the groups of RBH,SW and IPL 6 months after surgery.Conclusion:(1)Osteotome sinus floor elevation with simultaneous placement of dental implants adopted in severely atrophic maxilla can get a good bone augmentation effect and a high implant survival rate.(2)Preoperative residual bone height,sinus width and implant protrusion length did not affect sinus lift height and graft resorption amount of 6 months after surgery.