Assessment of cortical and medullar interforaminal donor site bone volumes in different vertical facial growth patterns.

Description :

Assessment of cortical and medullar interforaminal donor site bone volumes in different vertical facial growth patterns. The interforaminal area is located between the 2 mandibular mental foraminas and it’s considered as an ideal bone donor site due to its relative low complications rate, bone quality and quantity and the surgical technique. The interforaminal bone is composed of cortical and medullar bone, each type has its own properties and uses. It can be used as an onlay graft when it’s rich in medullar bone as well as a shell when it’s mainly formed of cortical bone. This study will assess the impact of the skeletal class on the cortical and medullar chin bone and will quantify the cortico-cancellous bone components volume, percentages and surface. Methodology The sample was divided in 3 groups of 60 (30 male and 30 female) according to their facial typology: hyperdivergeant, normodivergeant and hypodivergeant, and each group was divided into 2 subgroups following the patient’s gender. All CBCT examinations were performed using the ICAT scanner after setting the acquisition parameters as follows: 120 kV, 5 mA, and 4- to 6-second exposure time. Each file was converted to digital imaging and communications in medicine (DICOM) format. DICOM files were processed using NEWTOM software and BLUESKY. As for radiological measures the following steps were followed: -Skeletal class measurement according to SN-GOGN angle using BLUESKY software. -Standardisation of the patient head position according to the Frankfort plan. -FILES export in DIcom extension -Image analysis using ITK-SNAP -Region of interest setting: Cranial: 5 mm apical to the root apices of the mandibular teeth. Caudal: 2 mm cranial to the inferior border of the mandible. Distal: 5 mm mesial to the mental foramens. Buccal: buccal surface of the mandible. Lingual: 2 mm to the lingual surface of the mandible. - Contour segmentation and threshold setting: Cortical Maximum threshold fixed Medullar Minimum threshold fixed -Volume, percentage and surface calculation