Crestal vs Lateral Sinus Lift Augmentation

Inclusion Criteria: * Partially edentulous patient * Bilateral edentulism in posterior maxillae (premolars and molars) * 18 years or older * Able to understand and sign an informed consent. * At least 3 months after tooth extraction * Vertical bone height at the implant sites between 2 to 6 mm * Bone thickness at least 6 mm as measured on CBCT scan Exclusion Criteria: * general contraindications to implant surgery * subjected to irradiation in the head and neck area * immunosuppressed or immunocompromised * treated or under treatment with intravenous amino-bisphosphonates * poor oral hygiene and motivation * untreated periodontal disease * uncontrolled diabetes * pregnant or lactating * substance abusers * psychiatric problems * unrealistic expectations * lack of opposite occluding dentition/prosthesis * acute or chronic infection/inflammation * augmentation/implant placement * referred only for implant placement