Clinical and histological evaluation of atrophic maxillary ridges implant rehabilitation

Objective: the aim of this study was to evaluate early loading of PBR(Primary Bone Regeneration) implants inserted together with bone grafts in atrophic maxillary ridges. Methods: A sinus lifting was performed in a 8 patients (56years mean age, male sex, initial bone height of 1,5-2 mm and bone width of 5 mm) asking for a fixed implant-supported rehabilitation. They signed an informed consent. In every patient 2 implants (TMI®, Pressing Dental, San Marino, Italy) having 3.25 diameter and 10.5mm length were inserted together with a bone graft material (Physiograft®, Ghimas). 2.5 months after maxillary sinus augmentation one of the implants was retrieved and processed for undecalcified histology while the other one was loaded The endoral X-rays have been executed to 0, 2, 6, 9 and 12 months. Results: from the histomorphometric analysis, the graft material residuals accounted for the 46.98% of the bioptical volume, marrow spaces for the 18.76% and bone for the 32.87% (new bone: 22.62%, native bone: 10.25%). Well-mineralized regenerated bone with lamellar parallel-fibred structure and Haversian systems surrounded the residual graft material particles. The measured BIC amounted to 16.94%. No connective tissue was observed at the implant boundary surface. From clinical point of view there was no implant failure at the 2nd stage; neither mobility nor bleeding on probing. The endoral X-rays showed a complete bone defect filling and no change of the marginal bone level was observed. Clinical and X-ray results analized with T-Student test were statistically significant (P<0.005). Conclusions: these results showed as early loading of PBR implants inserted together bone grafts appears to be suitable for maxillary sinus floor augmentation, also in critical condition as minimal vertical bone height and shorter healing time.