Comportamento dos enxertos alógenos em bloco na reconstrução alveolar maxilar antes e após a instalação de implantes: análise tomográfica, histológica e imunohistoquímica da incorporação e remodelação

Abstract

Extremely resorbed alveolar ridges may lead to insufficient bone volume for dental implants placement, as well as jeopardize the final prosthesis in the aesthetic and functional standpoints. In the last decade, several studies have demonstrated the application of allogeneic grafts as bone substitutes in the alveolar reconstruction. Although case reports and case series are well documented in the literature, the use of the allograft bone requires more well-designed studies to guide the clinical practice. The aim of this study was to evaluate the clinical behavior of bone allograft blocks before and after implant placement and to investigate its incorporation and remodeling. In a 53-months period, patients who had indication for maxillary bone block reconstruction were consecutively included in the study. The trial was divided into four studies to investigate the following parameters separately: the incorporation and remodeling; the prevalence of complications and the survival rate of the implants; histological and tomographic long-termdata; and a pilotstudy. The grafts showed resorption rates from 13.98% (4 months) to 31.52% (6 months); new bone formation from 20.79% (4 months) to 27.2% (6 months); presence of bone cells and absence of inflammatory infiltratehistologically; intense positivity for a physiological bone activitymarker; 22.14% prevalence of complications; and a implants survival rate of 94.03%. After a 4 years follow-up with loaded implants, the grafts demonstrated a reabsorption rate from 2.1 to 7.7%. Histologically, remnants of allograft tissue were found along with an abundant number of osteocytes, osteoblasts and vessels. The evaluated parameters showed to be similar to other reconstructive procedures, demonstrating the viability of allogeneic bone block grafts as an option to augment thealveolar ridgefor dental implants placement