A Dual-parameter 3D Assessment of Alveolar Cleft Bone Grafts: Integrating Bone Density and Modified Volumetry

Alveolar cleft is a discontinuity of the maxillary alveolar process commonly associated with cleft lip and palate, leading to functional and aesthetic impairments. Secondary alveolar bone grafting (SABG) is the standard treatment to restore continuity. However, conventional postoperative evaluation relies solely on volume measurement. Although 3D computed tomography is widely used for this purpose, it ignores the porous, trabecular nature of newly formed bone (NFB), resulting in systematic underestimation of graft volume and incomplete assessment of regeneration.

We developed a dual-parameter evaluation method that integrates bone density analysis with a modified 3D volumetric algorithm accounting for trabecular porosity. Preoperative and 6-month postoperative computed tomography scans from 37 patients with unilateral alveolar cleft who underwent autologous SABG were used to construct matched maxillary models. Bone quality was quantified by mean Hounsfield units (HUs), and volumetric accuracy was enhanced by correcting for the porous structure of NFB using Smart Fill technology.

The conventional Boolean subtraction method yielded a mean NFB ratio of 44.87%. With our Smart Fill-enhanced method, the NFB ratio significantly increased to 55.85% (absolute increase 10.98%, relative increase 24.47%; P < 0.001). The mean bone density of the graft was 483.01 ± 78.11 HU (range: 358.77-614.64 HU), consistent with the quality of trabecular bone.

By simultaneously assessing the quantity (modified volume) and quality (density) of regenerated bone, this dual-parameter method provides a more accurate postoperative evaluation of SABG outcomes and can assist surgeons in clinical decision-making for alveolar bone repair.