melatonin proved an ability to repair bone defects and enhance osseointegration of dental implants. Also, hyaluronic acid has osteopromoting properties.

the effect of melatonin and hyaluronic acid on the newly formed bone in maxillary sinus augmentation was evaluated

16 participants with missing maxillary posterior teeth and residual alveolar ridge of at least 5 mm will be equally and randomly divided into two groups.

The study group will receive melatonin and hyaluronic acid after sinus membrane elevation and simultaneous implant placement while the control group will not receive any materials after sinus membrane elevation and simultaneous implant placement.

Inclusion Criteria:

• Age range will be between (30 - 50) years old.
• Patients with missed one or more of posterior teeth with minimum residual bone height 5 mm
• Adequate inter-occlusal space of at least 8 mm

Exclusion Criteria:

• Maxillary sinus diseases.
• Previous sinus surgery like the Caldwell-Luc operation.
• History of chemotherapy or radiotherapy to maxilla.
• Presence of Underwood's septa/severe sinus floor convolutions.
• Systemic disease affecting bone metabolism.
• Uncontrolled diabetes mellitus.
• Heavy smokers.
• Para functional habits.