This study evaluates the Bone Ring Technique, a single stage procedure that combines external sinus floor elevation and dental implant placement using an autogenous bone ring harvested from the chin. Ten patients with residual alveolar bone height ≤4 mm in the posterior maxilla will be enrolled. Implant stability (ISQ), vertical bone gain, peri implant bone density, and implant survival will be assessed over 6 months. The aim is to reduce treatment time and surgical interventions compared to traditional two stage approaches.

The Bone Ring Technique (BRT) was introduced by Giesenhagen (2004) to address severe posterior maxillary atrophy. In this prospective single arm case series, after obtaining ethics approval (DN 28102025 542, Damascus University), ten patients with residual bone height ≤4 mm will undergo: harvesting of an 8 mm cylindrical autogenous bone ring from the mandibular symphysis using trephine burs; creation of a lateral window in the maxillary sinus using a straight handpiece with a diamond round bur; meticulous elevation of the Schneiderian membrane; placement of the bone ring; simultaneous insertion of a dental implant (ICX) through the ring into the native ridge; filling of the defect with xenograft (bovine) particles; coverage with a collagen membrane; and suturing Primary stability will be measured immediately after implantation using resonance frequency analysis (Mega ISQ II).

CBCT scans (PaX i3D, VATECH) will be performed preoperatively, at 1 week, and at 6 months to quantify vertical bone gain (distance from implant shoulder to sinus floor) and peri implant bone density (Hounsfield like units).

Clinical follow up includes suture removal at 7 10 days and assessment of implant survival/success at 6 months (absence of mobility, pain, radiolucency, suppuration, crestal bone loss <1.5 mm).

Results will be submitted for publication in a peer reviewed journal.

Inclusion Criteria:

• Need for dental implant in posterior maxilla (premolar/molar).
• Residual alveolar bone height ≤4 mm on preoperative CBCT.
• Age ≥18 years.
• Controlled systemic health.
• Able to comply with procedures and follow up.
• Good oral hygiene.
• Signed written informed consent.

Exclusion Criteria:

• Uncontrolled systemic disease.
• Head/neck radiotherapy.
• Bisphosphonate therapy >3 years.
• Autoimmune disease affecting healing.
• Pregnancy/lactation.
• Active maxillary sinus pathology (sinusitis, cysts, polyps, tumours).
• Heavy smoking (>10 cigarettes/day).
• Severe bruxism.

De-identified individual participant data that underlie the results reported in the publication, specifically: Implant Stability Quotient (ISQ) values, vertical bone gain measurements (mm), and peri-implant bone density values (Hounsfield-like units).

Beginning 6 months after publication of the primary results. Data will be available for a period of 3 years.

With Researchers who submit a methodologically sound research proposal to the principal investigator, To achieve the aims specified in the approved research proposal, particularly for individual participant data meta-analysis or secondary analyses of maxillary sinus augmentation techniques

Starting 6 months after publication of primary results for a period of 3 years.

Requests for data access should be directed to the principal investigator (Adel Alassaf) via adel96.alassaf@damascusuniversity.edu.sy. Access will be granted to qualified researchers whose proposed use of the data has been approved by an independent review committee. Requesters will need to sign a Data Use Agreement (DUA) and ensure IRB approval or exemption for their proposed research.