Space-maintaining management in maxillary sinus lifting: a novel technique using a resorbable polymeric thermo-reversible gel.

Several techniques have been proposed to achieve sinus floor elevation and the formation of new bone through the grafting of autologous, heterologous, or alloplastic materials. The grafted materials act as a scaffold for bone formation inside the maxillary sinus. This study investigated a non-graft sinus lifting procedure using a resorbable polymeric thermo-reversible gel. A space-maintaining approach to sinus lifting, using a resorbable polymeric thermo-reversible gel, was applied in 11 patients undergoing implant treatment in the atrophic posterior maxilla. After a healing period of 6 months, a total of 14 implants were placed; biopsies were taken and evaluated histologically and histomorphometrically. The parameters evaluated included the percentages of new bone formation, residual gel, and fibrous tissue. Histological examination showed the formation of new bone with no fibrous tissue or severe inflammatory cellular infiltration. The percentage of newly formed bone was in the range of 54-60%; this consisted of both lamellar and woven bone. No foreign-body reaction was observed. The mean quantities of both residual gel and connective tissue were small. This non-graft sinus lifting procedure using a space-maintaining gel appears to stimulate predictable bone formation; it is thus a useful technique for promoting bone formation in the sinus.