Clinical, histological and histomorphometric evaluation of the healing of mandibular ramus bone block grafts for alveolar ridge augmentation before implant placement☆

Summary 

Background

Localized bone defects in the maxilla are commonly reconstructed with autologous mono-cortical bone blocks prior to the placement of dental implants. This study presents a clinical, histological and histomorphometric analysis on the use of mandibular ramus block grafts for ridge augmentation.

Materials and Methods

mono-cortical bone blocks from the mandibular ramus were grafted in 15 patients. The bone grafts were left to heal for period varying from 3 to 9 months. Afterwards, 30 implants were inserted and bone samples were removed for subsequent histological analysis.

Results

All the bone grafts were successful and resorption was minimal. There were no implant failures. At graft placement, mean lateral augmentation was 4.6±0.73mm, which, later, at the time of implant insertion, reduced to 4±0.77mm. Histological evaluation indicated signs of active remodelling in all specimens. However, the grafted bone contained substantial amounts of non-vital bone (NVB) and generally weak neo-vascularization regardless of the time of biopsies.

Conclusions

The outcome of the study suggests that the larger part of osteocytes in mono-cortical bone do not survive grafting and neo-vascularization of non-vital grafted bone is difficult because of the slow remodelling process into new vital.

Keywords: bone histology, bone histomorphometry, mandibular ramus, maxillary defects, mono-cortical bone block graft