[Maxillary sinus lift in conjunction with endosseous implants. A long-term follow-up scintigraphic study]

To evaluate the efficacy of bone scintigraphy in the long-term follow-up of maxillary sinus lift by a mixture of bovine hydroxyapatite and autologous fibrin glue in conjunction with the insertion of endosseous implants.

A three-years follow-up study involved 18 surgical interventions performed on 14 edentulous patients (4 F; 10 M; mean age 49 yrs) suffering from mono or bilateral severe distal maxillary resorbtion. The bone scintigraphy of the skull was performed before, 1-18 months and 36 months post-intervention. Perimplant bone metabolism was quantified by a parameter called M/V index, used to statistically compare normal, atrophic and regenerate maxillary bone. Conventional radiographies were performed every six months; CT dental-scan 12 months post-intervention.

Bone perimplant metabolism showed top values 1-4 months post-intervention (M/V%2-2.2); then it showed a decreasing trend and the lowest values 36 months post-intervention. M/V index in the atrophic (0.6) and normal (0.7) maxillary bone was lower (p<0.05) than in the new formed one (0.8). Radiologically a good integration of the dental implants was found in the new formed bone; the CT-measured average maxillary height was equal to 1 cm.

The combination of several bioactive components in the mixture used didn't allow to detect the bone inductive role of the single products. Instead, quantitative bone scintigraphy confirmed its efficacy to gain important data about natural history of the endosseous implants and the value of the surgical technique. In particular we observed complete osseous integration of dental implants inserted in the mix of bovine hydroxyapatite and autologous fibrin glue is achieved 2-3 years after the intervention. After this period, possible pathological aspects suggest an early treatment to save the implants.