Fig. 1

a Cross-sectional slice of the investigated molar, virtual implant was placed parallel to the long axis of the tooth (Straumann, bone level regular crossfit, 4.8 × 12 mm), and the level where the virtual implant was completely surrounded was identified. b The distance from the alveolar crest to the IAN, and the distance from the level where the virtual implant was completely surrounded by bone to IAN were measured. c CBCT sections 1, 3, 5, 7, 9, 11 mm apical to the alveolar crest were obtained. d Horizontal widths from the implant surface to the mesial and distal socket wall, the widths of inter-radicular septum, and the distances from implant surface to the buccal and lingual plate in each section were measured