Fig 2. Region of interest (ROI).

(A) Inter-radicular bone area used for bone quantity and quality measurements (MB, mesial-buccal root; IB, intermediate buccal root; DB, disto-buccal root; MP, mesial-palatine root; DP, disto-palatine root). (B) ROI in the area of the maxillary first molar is limited from below with a horizontal plane parallel to the occlusal plane (Plane B) passing through the alveolar ridge crest; from the top by a horizontal plane passing through the apex of the mesio-buccal root and disto-buccal root (Plane T). The area between Planes B and T was divided equally into occlusal, middle and apical thirds to measure bone quantity and quality. The rectangular boxes have different dimensions, increasing in size apically as the roots diverge.