Treatment of patients with extreme maxillary atrophy using sinus floor augmentation and implants: preliminary results

Twenty consecutive patients with extreme maxillary atrophy underwent bilate ral sinus floor augmentation, either with autogenous bone from the iliac cr est or with a combination of autogenous bone and hydroxyapatite. One patien t was treated using autogenous bone from the chin region. After a period of three to eight months, three to four implants were placed in each posterio r maxilla. Only 10 out of 155 inserted implants were located in the anterio r non-augmented maxilla. During the observation period of one to six years, four implants (one of them located in the anterior maxilla) had to be remo ved prior to prosthetic treatment. Another three implants were lost during the follow up period. This corresponds to a Kaplan-Meier survival probabili ty of 95.4% after 70 months. No statistically significant difference in imp lant success was observed between women and men (P=0.16). All prosthetic su prastructures are still in function despite these implant losses. Mean peri -implant bone resorption was 1.34 mm with no statistically significant diff erence between implants placed more mesially and those placed more distally in the augmented area, though a trend could be observed (P=0.058) for a mo re pronounced bone resorption around implants placed in the premolar region . When a mean mesial and distal bone resorption of >2 mm was considered in the calculation of the success prognosis, the survival probability dropped to 74.7% after 70 months.