Two-Stage Transcrestal Sinus Lift With Osseodensification: Allograft vs Autogenous-Xenograft

Evaluation of 2 Stage Transcrestal Maxillary Sinus Lift With Osseodensification Using Allograft Versus Autogenous-Xenograft in Severely Atrophic Posterior Maxilla: A Radiographic and Histomorphometric Study

This study is a prospective, randomized, controlled clinical trial comparing two grafting approaches used during two-stage crestal sinus lifting with osseodensification in patients with severely atrophic posterior maxillae (residual bone height ≤ 4mm). Participants will be randomly allocated in a 1:1 ratio to receive either allograft alone (Group A) or a mixture of autogenous bone and xenograft (Group B).

During the first stage, crestal sinus elevation will be performed using osseodensification drills, and the assigned graft material will be placed incrementally. Cone beam computed tomography (CBCT) will be performed immediately postoperatively and again after a six-month healing period to assess vertical bone gain.

At the second stage, during implant placement, bone-core biopsies will be harvested for histomorphometric analysis, and implant primary stability will be recorded using insertion torque values.

This randomized controlled trial will be conducted at the Oral and Maxillofacial Surgery (OMFS) Outpatient Clinic, Faculty of Dentistry, Cairo University, Egypt.

Eligibility criteria:

Inclusion Criteria:

Participants must:

1. Be 18-70 years old.
2. Have severely atrophic posterior maxilla with RBH 0-4 mm confirmed by CBCT after extraction of more than months.
3. 4. 5. Have adequate bone width of minium 7 mm. Be in good health status and able to undergo surgery. Provide informed consent and agree to follow study instructions.

Exclusion Criteria patients with:

1. Uncontrolled systemic diseases, immunosuppression, history of head & neck radiotherapy or chemotherapy.
2. Use of bisphosphonates, antiresorptive or antiangiogenic drugs.
3. Pregnancy
4. Heavy smoking (>10 cigarettes/day).
5. Active sinus disease, oral infection, untreated periodontal disease, or severe bruxism.
6. Poor oral hygiene
7. Anatomical issues such as sinus septa or inadequate ridge width preventing the OD approach.
8. Previous sinus lift or implant failure in the same site.

Intervention:

Pre-operative procedures:

1. Patient Selection and Eligibility Confirmation
2. Screening for inclusion and exclusion criteria.
3. Informed Consent obtained from all eligible participants prior to enrollment.
4. Explain study purpose, procedures, risks, and benefits to the patients
5. Record medical & dental history.
6. Clinical and Radiographic Examination
7. Randomization: Patients randomly assigned to:

Group A: Two-stage crestal sinus lifting with OD using allograft alone. Group B: Two-stage crestal sinus lifting with OD using a combination of autogenous bone and xenograft.

Intra-operative procedures STEP 1 1.0.12% chlorhexidine rinse 2. Local anesthesia with 4% articaine + epinephrine 1:100,000 3. Horizontal incision 2-3 mm palatal to crest, full-thickness flap elevation. 4. Pilot drill osteotomy to the sinus floor using Densah burs at 1000-1100 RPM with copious irrigation. 5.Controlled advancement 1-2 mm beyond sinus floor to elevate Schneiderian membrane 6.Graft material compacted incrementally (1 mm lifts) using Densah bur in low-speed CCW compaction mode. Group A: Hydrated Allograft Group B: Autogenous bone harvested from intra-oral site (External oblique ridge/ chin/ maxillary tuberosity) using ACM bur mixed with xenograft. 7.flap closure with resorbable sutures (4-0 Vicryl). 8.Immediate Postoperative CBCT to

1. Confirm membrane integrity
2. Evaluate graft placement and initial vertical augmentation
3. Serve as baseline for later comparison

STEP 2

1. Six-Month Postoperative CBCT

   •Performed before implant placement to measure: A) Height of newly formed bone B) Graft consolidation and density. C) Final vertical bone height.

2. Bone-core biopsies will be taken at re-entry using a trephine bur and fixed for histologic processing.

3. Histologic and Histomorphometric analysis to assess the vital bone, residual graft, marrow tissue, and maturation.

4. Implant osteotomy will be done with osseodensification, implants placement and primary stability measuring using insertion torque.

Post-Operative Care

• Standard antibiotic and analgesic protocol.
• Instructions for oral hygiene and follow-up.

outcomes

1. Primary outcome Vertical bone height after sinus lift after graft healing, before implant placement
2. Secondary outcomes Histomorphometric image-analysis applied to the stained biopsy section
3. Implant primary stability at implant placement time

Inclusion Criteria:

• Participants must:

  1. Be 18-70 years old.
  2. Have severely atrophic posterior maxilla with RBH 0-4 mm confirmed by CBCT after extraction of more than months.
  3. 4. 5. Have adequate bone width of minium 7 mm. Be in good health status and able to undergo surgery. Provide informed consent and agree to follow study instructions.

Exclusion Criteria:

• patients with:

  1. Uncontrolled systemic diseases, immunosuppression, history of head & neck radiotherapy or chemotherapy.
  2. Use of bisphosphonates, antiresorptive or antiangiogenic drugs.
  3. Pregnancy
  4. Heavy smoking (>10 cigarettes/day).
  5. Active sinus disease, oral infection, untreated periodontal disease, or severe bruxism.
  6. Poor oral hygiene
  7. Anatomical issues such as sinus septa or inadequate ridge width preventing the OD approach.
  8. Previous sinus lift or implant failure in the same site.