Table 2 Inclusion and exclusion criteria

Age > 20 years old

In need of complicated bone augmentation procedure

Being edentulous for more than 6 months

Local or systemic contraindication for implant therapy (i.e. uncontrolled diabetes, hemophilia, metabolic bone disorder, history of renal failure, radiation treatment to the head or neck region, current chemotherapy, and pregnancy etc.)

Willing to receive implant treatment

Smoking more than 10 cigarettes per day

Buccal-lingual width of keratinized tissue less than 6 mm