Rialzo del pavimento sinusale in mascellari estremamente atrofici:valutazione della neoformazione ossea con innesti di osso omologo mineralizzato

This paper examines the healing, by means of mineralized human bone allograft in sinus lift procedures, of severe maxillary atrophy, also in relation to the sinu-sal cavity size.In a two stage protocol, 14 core biopsies have been taken by a trephine bur to place the implants in 12 patients, all having the crestal bone lesser than or equal to 2 mm. Sinus augmentation by lateral window was performed six months earlier using a mixture of cortical/cancellous MHBA particles (80%/2O%) (Puros®). Microradiography, histology and histochemistry of methacrylate-embedded sections were performed to evaluate the amount of bone and graft. Newly formed bone around MBHA particles was found in all 14 biopsies. Bone chiefly showed a woven structure; sometimes however a lamellar structure was reported on the periosteal side. Six months later, the mean bone amount in narrow sinuses was 25.6% and the graft about 15.8%.Based on the preoperative computer tomography sections (< or > 15 mm) the sinusal cavities were classified as Narrow Sinus (NS) and Broad Sinus (BS). The mean bone amount was 30.6% (NS) and 2O.6% (BS). The greater bone amount of NS was statistically significant (P<O.OO5) after Mann-Whitney test. To conclude, the use of the MHBA mixture (80%/ 20%) appears to promote adequate bone formation in severely atrophic maxillas.Our preliminary results, prove that the larger the sinus, the longer the maturation time required to achieve a suitable amount of new bone formation.