An RCT Comparing Xenograft and Allograft for Ridge Preservation

Study Overview
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Brief Summary
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To compare the effectiveness of demineralized freeze-dried bone allograft + cross-linked collagen membrane with xenograft + non-cross-linked collagen membrane for posterior extraction socket ridge preservation.

Detailed Description
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Buccal bony wall loss is a common sequela following tooth extraction, and guided bone regeneration (GBR) is a common treatment for the regeneration of ridge form and volume preservation allowing dental implant placement. Many bone augmentation biomaterials are employed to accomplish GBR, and both the medical/ dental community and, subsequently, patients benefit from understanding whether a given GBR biomaterial might be more efficacious. To this end, a randomized, case series comparison of allograft + x-linked collagen membrane versus xenograft + non-x-linked collagen membrane would be beneficial to both the dental community and patients. The study compares the effectiveness of demineralized freeze-dried bone allograft + x-linked collagen membrane with xenograft + non-x-linked collagen membrane for posterior region extraction socket ridge preservation.

Official Title
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A Prospective, Randomized, Controlled, Multi-center Study With Direct Measure and Histological Evaluation Comparing Xenograft and Allograft for Posterior Buccal Dehiscence Extraction Site Ridge Preservation

Conditions
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Tooth Loss

Intervention / Treatment
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* Device: allograft + x-link collagen membrane
* Device: xenograft + non-x-link collagen


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects 18 to 70-yrs of age Subject indicated for posterior tooth extraction (from 1st premolar to 1st molar) intended for implant placement, with adjacent teeth intact (for stent indexing) Subjects with extraction site bony buccal dehiscences at least 1/3 the depth of socket and 1/3 the mesial-distal width of tooth socket Subjects will have read, understood and signed an institutional review board (IRB) approved Informed Consent Form (ICF). Subjects must be able and willing to follow study procedures and instructions. Exclusion Criteria: Subjects with a history of any tobacco use within the last six months. Subjects with healing disorders (i.e., diabetes mellitus, cancer, HIV, bone metabolic diseases) that could compromise wound healing and/ or preclude implant surgery; or who are currently receiving or have received within two months prior to study entry, systemic corticosteroids, immunosuppressive agents, radiation therapy, and/or chemotherapy which could compromise wound healing and preclude periodontal surgery. Subjects taking intramuscular or intravenous bisphosphonates. Subjects who have a known allergy or sensitivity to alginate, latex, collagen or acrylic. Female subjects who are pregnant or lactating, or who intend to become pregnant during the study duration Subjects participating in other clinical studies involving therapeutic intervention (either medical or dental). Subjects, who in the opinion of the investigator, for any reason other than those listed above, will not be able to complete the study per protocol.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: allograft + x-link collagen membrane<br>Demineralized freeze-dried allograft + x-linked collagen membrane will be used for guided bone regeneration of dehiscence buccal defects post extraction. | Device: allograft + x-link collagen membrane<br>* Following resolution of any periodontal issues in the region of study and administration of pre-surgical antibiotic, minimally traumatic extraction with periotomes and flap reflection will be performed. Allograft will be placed according to randomization schedule and in quantity to fill the extraction socket and mimic surrounding ridge dimension. X-link collagen membrane will be trimmed to extend at least 2 mm beyond the margins of the defect, and soft tissue flaps will be re-approximated using resorbable Vicryl® 6-0.<br>|
| Active Comparator: xenograft + non-x-link collagen<br>Xenograft + non-x-linked collagen membrane will be used for guided bone regeneration of dehiscence buccal defects post extraction. | Device: xenograft + non-x-link collagen<br>* Following resolution of any periodontal issues in the region of study and administration of pre-surgical antibiotic, minimally traumatic extraction with periotomes and flap reflection will be performed. Xenograft will be placed according to randomization schedule and in quantity to fill the extraction socket and mimic surrounding ridge dimension. Non-x-link collagen membrane will be trimmed to extend at least 2 mm beyond the margins of the defect, and soft tissue flaps will be re-approximated using resorbable Vicryl® 6-0.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone Ridge Buccal-Lingual and Apico-Coronal Measures at 6 Months | The primary efficacy parameter will be ridge volume preservation as measured apico-coronal and buccal-lingual using a preformed and marked stent. | Six Months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| New Bone Plus Graft Content at 6-months | New bone and graft content are measured as histomorphometric % vital bone and % mineral (graft remnants) from mid-section bone core biopsies. Histomorphometric analyses are performed with imaging software on composite overview scans. The area of new healing (versus old/ original bony tissues) is demarcated in each section. Within this area, the percentage contributions of each tissue type within the overall area of newly healed tissue is computed, i.e., new bone plus graft content added with connective tissue/ marrow elements totals 100% of the new healing area. | Six Months | 
| Wound Closure at 4-weeks | Suture line gap will be measured (buccal-lingual) with a UNC-15 Probe, rounding down to the nearest 0.5 mm. | 4-weeks |