Ridge Preservation Following Tooth Extraction Using Porcine and Bovine Xenograft Materials

The study is designed to examine histologic wound healing following ridge preservation using bovine xenograft and porcine xenograft materials.

This entire protocol involves procedures that are standard care. The study is a 2-arm, parallel-design, randomized, prospective clinical trial. The test group subjects will have extraction sockets grafted with porcine xenograft (Zcore). This test group will be compared to an active control group using bovine xenograft (Bio-Oss). The null hypothesis is that there will be no significant difference in formation of new vital bone between treatment groups (primary outcome).

In keeping with the protocol our study group has used several times before, the plan will be to extract non-molar teeth and graft with the test/control materials. Each subject will provide a single non-molar tooth site for study treatment. The graft material will be covered with a non-resorbable dense polytetrafluoroethylene (d-PTFE) membrane (TXT-200 singles, Osteogenics Inc). This d-PTFE membrane will be removed 4 weeks after placement during the 4-week post-op visit. Following 18-20 weeks of healing, the dental implant will be placed. To place a dental implant, an osteotomy (hole in the bone) is prepared into which the implant is placed. This osteotomy can be prepared with either a solid drill, in which case the bone that is removed is suctioned into the suction system, or with a hollow trephine drill into which a core of bone can be collected. The only "research procedure" being done in the current study is the collection of this bone core biopsy for histologic evaluation. The core biopsy will then be evaluated for the primary histologic outcome of % vital bone formation and secondary histologic outcome of % residual graft material.

Inclusion criteria

• Patients will be included in this study if they qualify the following inclusion criteria:
• Live within 50 miles from the School of Dentistry, University of Texas Health Science Center at San Antonio
• Are able to attend a minimum of 6 visits over a 4-5 month period, as required by the study protocol
• A single rooted tooth that has been identified as requiring extraction
• Desire a dental implant to replace the missing tooth
• Have adequate restorative space for a dental implant-retained restoration
• Have at least 10mm of alveolar bone height, without impinging on the maxillary sinus or inferior alveolar canal.
• Have a dehiscence of the buccal or lingual bony plate of the tooth socket extending no more than 50% of the total depth of the socket.
• Female patients who have undergone a hysterectomy, tubal ligation, or menopause, and non-pregnant women of child-bearing potential.
• Are nonsmokers or former smokers. Current smokers may only be included if they smoke <10 cigarettes per day

Exclusion criteria

• Patients who live more than 50 miles from the School of Dentistry, University of Texas Health Science Center at San Antonio
• Patients who do not meet all the inclusion criteria or who will not cooperate with the required follow-up schedule.
• Patients will are mentally incompetent, prisoners, or pregnant.
• Pregnant women or women intending to become pregnant during the study period.
• Smokers who smoke >10 cigarettes per day
• Clinical and/or radiographic determinations which will preclude inclusion in this study are: Active infection other than periodontitis; Inadequate bone dimensions or restorative space for a dental implant; Presence of a disease entity, condition or therapeutic regimen which decreases probability of soft tissue and bony healing, e.g., poorly controlled diabetes, chemotherapeutic and immunosuppressive agents, autoimmune diseases, history of bisphosphonate use or long-term steroid therapy
• Positive medical history of endocarditis following oral or dental surgery.