Relations between bone density from computed tomography and bone regeneration after reduction mandibuloplasty.

BACKGROUND

Bone regeneration in the mandibular angle region after reduction mandibuloplasty may compromise the aesthetics of the lower face and thus lead to revision surgery. Bone quality is known to play an important role in osteogenesis. However, no study has evaluated the relationship between mandibular bone quality and bone regeneration volume.

METHODS

The bone density of the mandibular angle immediately after surgery (BD) was determined as the grey level in computed tomography (CT) images. Based on the immediate postoperative and long-term follow-up CT images, the volumes of the regenerated angle (VSA) and the regenerated outer cortex (VOC) were measured after model reconstruction, automatic alignment and Boolean operation. Correlation analyses were then performed between VSA and BD, VOC and BD.

RESULTS

23 patients (46 mandibular angles) were included in this study. The average BD was 907.09 ± 111.89 HU. The mean VSA was 201.66 (131.73-357.24) mm3. Spearman correlation analysis revealed a positive correlation between BD and VSA (r = 0.5449, p < 0.0001). The mean VOC was 236.23 ± 151.35 mm3. Pearson correlation analysis found a negative correlation between BD and VOC (r = -0.3501, p = 0.0171).

CONCLUSIONS

CT images can provide a quantitative assessment of mandibular bone quality. BD may influence the volumes of bone regeneration in different areas of the mandibular angle portion after reduction mandibuloplasty, in the regenerated angle area positively and in the regenerated outer cortex region negatively. Therefore, slight over-grinding may be a choice to prevent secondary angulation.