Fig. 5

Box plots showing changes in mean vertical increased bone height in the panoramic views at each time point. a In subantral inlay type bone graft sites, Group 1 shows a greater reduction of residual bone height than Group 2. In Group 1, the mean increased vertical bone height is 10.8 ± 0.9 mm immediately after the operation (T1), but it promptly decreases to 8.2 ± 0.9 mm 6 months postoperatively (T2), and continuously reduces to 5.6 ± 1.2 mm by T5. However, in Group 2, there is no statistical difference in the mean increased bone height between T1 (9.6 ± 1.0 mm) and T2 (8.7 ± 1.0 mm), and this gradually decreases to T5 (7.3 ± 1.2 mm). b Onlay type bone graft sites show similar mean residual bone height changes to the inlay type bone graft sites. Group 1 exhibit more rapid vertical bone loss than Group 2. In both groups, the largest bone loss occurs between T1 and T2. Data represent mean ± standard deviation of increased vertical bone height at each time point, and different letters denote statistically significant differences (p < 0.05)