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.

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 (V_SA) and the regenerated outer cortex (V_OC) were measured after model reconstruction, automatic alignment and Boolean operation. Correlation analyses were then performed between V_SA and BD, V_OC and BD.

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

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.