A Retrospective Clinical Study Of Implant In Sinus-lifted Maxillary Bone

[Objective]:In the maxillary posterior region,atrophy of the alveolar ridge after tooth loss,more cortical bone and the anatomical position of the maxillary sinus,it is considered to be challenging area for dental implantation.With the development of dental implant technology,maxillary sinus floor elevation surgery comes into being,widely used to treat the loss of maxillary posterior teeth,but conclusions on its long-term clinical effects are inconsistent.To evaluate the clinical effect of dental implantation in the patients who missed at least one maxillary posterior tooth with insufficient maxillary bone volume over a time period of 6-9 years.[Methods]:In this study,69 patients suffered from maxillary posterior teeth loss were enrolled,with 95 dental implants inserted from 2007 to 2010.For group A,29 patients were placed 38 implants via maxillary sinus floor lift with bone grafts technique.For group B,17 patients were placed 24 implants via maxillary sinus floor lift without bone grafts technique.For group C,25 patients were placed 33 implants positioned in native areas beneath the sinus.All patients were followed up for 72 to 108 months after surgery.The aspects of implant survival rate,peri-implant soft tissues status,patients' satisfaction degree,marginal bone loss,bone substitutes volume and maxillary sinus floor level,the length of implant protruding into the sinus,the height of maxillary sinus mucosa elevation and the endo-sinus bone gain are evaluated.[Results]:The total implant survival rate showed 97.9%with 2 implants failed in 6 months after surgery,and there was no statistically significant difference in survival rate between the different groups.There was no difference between patients' satisfaction degree for group A,group B and group C.Similarly,no difference was found for peri-implant soft tissues status which were in good condition at 6-9 years after surgery.MBL was discovered with significant difference between 6 months and 6-9 years in three groups and was not associated with types of surgery.Large parts of maxillary sinus floor were risen for group A.We found that the volume of graft materials remained 64.23%at 6 months and 6.56%at 6-9 years after surgery.The correlation index between the length of implant protruding into the sinus and the new bone formation was 0.533,which has a positive correlation,similarly,that of the height of maxillary sinus mucosa elevation and the new bone formation was 0.334,which has an unobvious correlation.[Conclusion]:The results suggest that implants in sinus-lifted maxillary bone with 6-9 years follow-up achieve good clinical effect.The rise rate of maxillary sinus floor is increased after bone graft but bone substitutes are absorbed at a high proportion.