An interventional study of Bone Ring Technique (BRT) in Maxillary Deficiency and Bone Resorption, sponsored by Damascus University. Recruiting at 1 site in Syria. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-09-01.
Sponsored by Damascus University · Not applicable, Interventional, and Treatment
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.
62 studies on the registry are indexed under Retrognathia; 15 are open to participants now.
This study's planned enrollment of 10 is below the median of 34 across 52 interventional studies indexed under Retrognathia.
Browse Retrognathia studies →Damascus University is the lead sponsor of 212 studies on the registry; 11 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Eligible patients with posterior maxillary atrophy (RBH ≤4 mm) will undergo a single surgical session. Preoperatively, CBCT will be performed. Under local anesthesia, the surgeon will harvest an autogenous bone ring from the chin (mandibular symphysis) using trephine burs. A lateral window will be created in the maxillary sinus wall using a straight handpiece with a diamond round bur. The sinus membrane will be elevated, and the bone ring will be placed into the sinus. A dental implant (ICX) will be inserted through the ring into the residual ridge. The defect will be filled with xenograft particles and covered with a collagen membrane. Sutures will be removed at 7-10 days. Patients will be followed for 6 months with clinical and CBCT evaluations.
Procedure: Bone Ring Technique (BRT)
The Bone Ring Technique (BRT) is a one-stage surgical procedure that combines external maxillary sinus floor elevation with simultaneous dental implant placement. An autogenous bone ring is harvested from the mandibular symphysis using trephine burs. The sinus membrane is elevated via a lateral window approach created with a straight handpiece and diamond round bur. The bone ring is then placed into the sinus cavity, and a dental implant is inserted through the ring into the residual alveolar bone. The surgical site is augmented with xenograft particles and covered with a collagen membrane.
Implant Stability Quotient (ISQ).
Measured by resonance frequency analysis with MEGA ISQ II (MegaGen, Korea), Four readings per implant (mesial, distal, buccal, lingual); mean value reported
Time frame: Immediately after implant placement (baseline) and 6 months post_surgery (before prosthetic loading).
Vertical Bone Gain (mm)
Distance from implant shoulder to highest point of elevated sinus floor; measured on coronal sections using Ez3D plus software
Time frame: at preoperative, 1 week post_surgery , 6 months post_surgery
Peri implant Bone Density (gray values)
regions of interest: coronal, middle, apical thirds
Time frame: at preoperative, 1 week post_surgery , 6 months post_surgery
Implant Survival & Success
Survival = implant in situ. Success = absence of mobility, persistent pain, peri implant radiolucency, suppuration; and crestal bone loss \<1.5 mm on CBCT.
Time frame: 6 months post_surgery
Plan to share: Yes — 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
Supporting information: Study protocol, Statistical analysis plan, Informed consent form
Time frame: Starting 6 months after publication of primary results for a period of 3 years.
Access criteria: 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.
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