Fig. 1 Osteological survey of New Zealand White rabbit skull. Preserved skull of a NZW rabbit (Oryctolagus cuniculus) showing the depth and orientation of the maxillary incisor alveolus after removing the central incisor. The alveolus penetrates into the maxillary bone laterally with strong curvature toward the palatal shelf. The tooth extends just shorts of the extensively aerated maxillary sinus

Fig. 2 Imaging survey. Micro-CT three-dimensional reconstruction of a preserved skull of a NZW rabbit showing the depth and morphology of the extraction socket. Coronal sections at the level of the central incisors show thin bony plates separating the tooth from the nasal cavity

Fig. 3 Postmortem pilot alveolar cleft creation surgery. a–i Postmortem pilot alveolar cleft creation surgery of a sacrificed NZW rabbit showing the modification of the extraction socket to expose the nasal lining. The defect can be completely covered by mucosa to allow healing and enable mucosal coverage of the cleft surfaces

Fig. 4 Postmortem imaging. Micro-CT imaging of the created cleft in a pilot postmortem surgery. Coronal view at the level of the anterior part of the extraction socket shows a complete cleft 8 mm wide extending from the oral cavity to the nasal cavity. Coronal view at the apical region of the extracted central incisor shows a residual defect with all bony walls intact

Fig. 5 In-vivo alveolar cleft creation surgery. a–l In-vivo cleft creation surgery showing the modification of the extraction socket to expose the nasal lining. Distance material of bone wax and oxidized cellulose were used to keep the defect open and allow the mucosa to cover the cleft surfaces

Fig. 6 Wound healing. Healing of the surgery site 1 week after surgery (a) and 3 weeks after surgery (b). c Healed cleft site 8 weeks after surgery and before exposure of the alveolar cleft for bone grafting. Note the fistula overlying the cleft side indicating the establishment of an underlying bone defect