A randomized, controlled, multicentre clinical trial of post-extraction alveolar ridge preservation.

AIM: To compare the effectiveness of two-ridge preservation treatments. MATERIALS AND METHODS: Forty subjects with extraction sockets exhibiting substantial buccal dehiscences were enrolled and randomized across 10 standardized centres. Treatments were demineralized allograft plus reconstituted and cross-linked collagen membrane (DFDBA + RECXC) or deproteinized bovine bone mineral with collagen plus native, bilayer collagen membrane (DBBMC + NBCM). Socket dimensions were recorded at baseline and 6 months. Wound closure and soft tissue inflammation were followed post-operatively, and biopsies were retrieved for histomorphometric analysis at 6 months. RESULTS: Primary endpoint: at 6 months, extraction socket horizontal measures were significantly greater for DBBMC + NBCM (average 1.76 mm greater, p = 0.0256). Secondary and Exploratory endpoints: (1) lingual and buccal vertical bone changes were not significantly different between the two treatment modalities, (2) histomorphometric % new bone and % new bone + graft were not significantly different, but significantly more graft remnants remained for DBBMC; (3) at 1 month, incision line gaps were significantly greater and more incision lines remained open for DFDBA + RECXC; (4) higher inflammation at 1 week tended to correlate with lower ridge preservation results; and (5) deeper socket morphologies with thinner bony walls correlated with better ridge preservation. Thirty-seven of 40 sites had sufficient ridge dimension for implant placement at 6 months; the remainder were DFDBA + RECXC sites. CONCLUSION: DBBMC + NBCM provided better soft tissue healing and ridge preservation for implant placement. Deeper extraction sockets with higher and more intact bony walls responded more favourably to ridge preservation therapy.

Group Practices and Partnerships: A traditional model that Fits Many Situations.

The traditional group practice model can take many forms, including general practitioners, specialists, and combinations, as well as solo practitioners sharing space and staff, partnerships, and other legal entities. These practices may share some or all staff functions, including contracting for some functions. The essential characteristic is that those treating patients also have full control over and often direct management of the business aspects of the practice. The most important requirements for success in this model may be a common philosophy of patient care and mutual trust regarding business matters.