Ridge Preservation Using a Flapless Technique with the Membrane Exposed

Objectives: Bone resorption following tooth extraction may lead to esthetic and functional disadvantages and even compromise future implant placement. Many techniques for ridge preservation have been advocated to minimize bone resorption. The purpose of this retrospective study was to evaluate the outcomes of a flapless ridge preservation technique with a composite bone graft and a collagen membrane.

Materials & Methods: Patients who had tooth extraction and ridge preservation were recruited (n=102). Ridge preservation was performed with a flapless technique using demineralized freeze dried bone allograft (DFDBA) and anorganic bovine material with P-15 (ABM/P-15). A collagen membrane was utilized as a barrier and left exposed. After a mean period of 5.4 months, 91 implants were placed. Implant survival rate was determined at least 1 year after functional loading. Percentage of bone fill (BF) was evaluated radiographically. Descriptive statistics and independent t-test were used for statistical analysis.

Results: The overall mean BF was 92.0±13.3%. Overall implant survival rate was 96.7%. The relationships between gender, age, location of the procedure and BF were not statistically significant. BF in patients with a history of hypertension (84.6±9.7%) was statistically significantly less than that in patients without it (93.4±13.4%). (p<0.01) Patients who had failed implants demonstrated less BF than patients who had survived implants: 74.7±19.6% versus 92.7±12.7%. (p<0.019)

Conclusions: 1) Ridge preservation using a composite bone graft and an exposed collagen membrane seems to be an effective and predictable method; 2) The survival rate of the implants in the preserved areas is similar to the survival rate of the implants in previous studies. 4) A history of hypertension may adversely affect the amount of BF. 3) The patients who had less BF after ridge preservation are more likely to have implant failure.