Radiographic evaluation
bone defects, volume reduction
To compare the size of the bone defects, cone-beam computed tomography (CBCT) was performed at 1 week, 3 months, and 6 months postoperatively using a CS9300 3D CBCT unit (Carestream Health Inc., Rochester, NY, USA) with a set value of 4–10 mA and 85–120 kV, and a voxel size of 0.2–0.3 mm.To measure the volume of bone defects, CBCT image files in digital imaging and communications in medicine (DICOM) format were transferred to Mimics Medical software version 21.0 (Materialize, Leuven, Belgium). The threshold was appropriately adjusted to mark bone defects. In this study, the standard threshold range was set from − 326 to 670, and a fixed threshold was applied equally to all patients. After image segmentation in the axial, coronal, and sagittal planes, the bone-defect volume was calculated by converting the image into a 3D image (Fig. 
Measurement of the bone-defect volume using Mimics medical software
Representative sagittal cone-beam computed tomography and 3D images of the bone defect. Bone regeneration was compared between the groups based on the rate of volume reduction of the bone defects. As the initial lesion size varied in each patient, the proportion of unfilled lesions was calculated by dividing the mean V