This study is intended to evaluate the efficiency of utilizing "dynamic implant valve approach" (DIVA) system in treating chronic maxillary sinusitis.

A prospective study aimed to test the efficiency of a minimal interventional approach in treating chronic maxillary sinusitis. The "dynamic implant valve approach" (DIVA), a minimally invasive approach utilizes a dental implant, designed with an internal sealing screw that might serve as drug delivery system via its channel. The implant is inserted to a posterior maxillary edentulous area, creating a connection between the sinus cavity and the oral cavity (Oro-antral connection), hence, provides a controlled working channel for diagnosis and treatment of the disease (e.g; allowing drainage, lavage and sinus endoscopy). The implant is a medical device approved for use at the anatomical area of interest.

The treatment method proposed in this study is based on the principle of a conventional treatment of washing the maxillary sinus cavity called "Antral puncture and lavage".

The changes that are proposed in this study could make the operation more convenient and effective in the therapeutic level, both for the patient and the clinician for the following reasons:

• DIVA (Dynamic Implant Valve Approach) Implant with a multi- useful working channel: the mere presence of the canal in the center of the implant with a screw seal, ensures controlled Oro-antral connection, and enables multiple endoscopy and lavage procedures until resolution of the pathological condition is achieved.
• The anatomical location of the puncture / penetration to the sinus - is performed in the maxillary edentulous region. This is the lowest area of the sinus cavity (standing or sitting posture), which utilizes gravity for drainage and extraction of the contaminated contents of the sinus.

By appropriate advance planning, the implant, after eradication of the disease, can later be used for prosthetic purposes.

Inclusion Criteria:

• No medical history of diseases involving bone metabolism
• Unilateral or bilateral maxillary sinusitis, as evident by radiographic and endoscopic modaleties, which have not responded to optimal conservative treatment
• Patient who is edentulous in the maxillary region and is interested in dental implant
• The patient does not participate in another clinical study
• The patient can read and understand the informed consent

Exclusion Criteria:

• Medical history of increased risk of developing bone necrosis (MRONJ - medically related osteonecrosis of the jaw , or ORN - osteoradionecrosis)
• patients who are not interested or need dental implants
• Patients with maxillary sinus neoplastic pathology
• Chronic maxillary sinusitis with polyps
• Pregnant women