Outcomes and treatments of mal fractures caused by the split-crest technique in the mandible.

In this study, we investigated cases of mal fracture occurring during the split-crest procedure. In all subjects (six patients), the free cortical bone segment caused by the mal fracture was carefully maintained in the lateral position without fixation using a titanium plate or screw. On pre- and postoperative multiplanar reconstruction CT, the average total alveolar increase was 5.0 mm in the lower portion 1 mm from the top of the alveolar ridge, and the average total alveolar increase in the lower portion 11 mm from the top of the alveolar ridge was 2.2 mm. A total of 11 dental implants were placed immediately at the same time as the split-crest procedure, while three dental implants were placed after a waiting period of 4-11 months from bone augmentation. During an average follow-up of 27.8 months, there were no complications or cases of failed implants. Consequently, among the patients who experienced mal fracture during the split-crest technique, a sufficient volume of alveolar bone was obtained without the need for rigid fixation of the free bone segment, and the dental implants placed within the area of the mal fracture showed a good prognosis.