Split-crest technique with inlay bone block grafts for narrow posterior mandibles: a retrospective clinical study with a 3-year follow-up

The use of the split-crest technique (SCT) and bone block grafts provides benefits to horizontal bone augmentation. However, no information is currently available to evaluate the clinical effects of SCT combined with inlay bone block grafts on soft and hard tissues of the narrow posterior mandibles. In this study, 56 healthy patients underwent SCT to augment the alveolar ridge width. Implant placement was performed 3 months after SCT, and the implants were restored 3 months after placement. A planned follow-up was performed to analyze various clinical features, including X-ray radiographs, alveolar ridge width, and keratinized mucosal width, after SCT to evaluate the success of the procedure. The incisions healed well in all patients. The average initial alveolar ridge width was 2.78 +/- 0.56 mm, which increased to 6.67 +/- 0.60 mm after SCT. Three months later, this width declined slightly to 6.19 +/- 0.48 mm. The average initial keratinized mucosal width was 2.83 +/- 0.66 mm, which increased to 6.00 +/- 0.71 mm 3 months later. Both at 3 months and 1 year after the procedure, vertical bone loss at the buccal sites was 1.32 +/- 0.56 mm and 1.94 +/- 0.54 mm, respectively. Survival rates of the implants were 100% after 3 years. SCT with inlay bone block grafts was successfully applied to narrow posterior mandibles with efficient augmentation of soft and hard tissue widths. The findings of this study aim to identify future beneficial applications of SCT.