This prospective randomized clinical study evaluates and compares three different grafting approaches (allograft, xenograft, and combined grafting) used in lateral maxillary sinus augmentation prior to dental implant placement.

Patients with posterior maxillary bone deficiency (residual bone height ≤4 mm) undergoing sinus lift surgery were randomly assigned to one of three grafting groups. Cone-beam computed tomography (CBCT) was used to assess bone height before surgery, immediately after grafting, and at 6 months. During implant placement at 6 months, bone biopsy samples were collected from the grafted sites for histological and immunohistochemical evaluation.

The study aims to assess vertical bone gain, graft height stability, and biological bone healing using osteocalcin, osteopontin, and RUNX2 markers. The results are intended to provide clinically relevant information regarding the volumetric and biological behavior of different graft materials used in maxillary sinus augmentation.

Inclusion Criteria:

• Adults aged 18 to 75 years.
• Patients presenting with posterior maxillary edentulism requiring dental implant rehabilitation.
• Residual alveolar bone height of 4 mm or less, indicating the need for lateral maxillary sinus augmentation.
• Patients suitable for lateral sinus lift surgery based on clinical and radiographic evaluation.
• Ability to provide written informed consent.

Exclusion Criteria:

• Systemic conditions that could affect bone healing (e.g., uncontrolled diabetes, metabolic bone diseases).
• History of radiotherapy or chemotherapy to the head and neck region.
• Active sinus pathology or chronic sinusitis.
• Heavy smoking (more than 10 cigarettes per day).
• Pregnancy or lactation.
• Use of medications known to affect bone metabolism.

Individual participant data will not be shared.

Histological and immunohistochemical evaluations were performed by a blinded examiner.