Alveolar ridge preservation using an intentionally exposed xenogeneic collagen matrix seal in sockets with varying proportions of vertical bone resorption: a pilot study.

PURPOSE: This pilot study investigated the effects of different extraction-socket bone-resorption patterns on alveolar ridge preservation (ARP) performed with an open-wound healing technique.

METHODS

Sites were divided into two groups according to cone-beam computed tomography (CBCT) findings obtained immediately after ARP surgery (T1): group 1 included sockets with vertical bone resorption >1/3 of the buccal/labial or lingual/palatal bone wall, and group 2 included sockets with vertical bone resorption ≤1/3 of the buccal/labial and lingual/palatal bone walls. Follow-up CBCT was performed approximately 5 months after surgery (T3). Hard-tissue changes were measured by superimposing CBCT images obtained at T0 (before tooth extraction), T1, and T3. Soft-tissue healing was evaluated at suture removal (T2), and biopsy specimens were collected before implant placement.

RESULTS

Sixteen participants with 19 sites completed this pilot study. All included patients underwent ARP with an intentionally exposed xenogeneic collagen matrix seal; however, one patient did not undergo implant-placement surgery at our hospital. Overall, CBCT measurements of ridge alterations showed excellent intra-rater reliability and minimal systematic bias. Bone resorption occurred in both groups (P<0.05), reflecting the natural bone-remodeling process. However, no intergroup differences were observed in horizontal or vertical dimensional changes. In addition, locally estimated scatterplot smoothing analysis identified bootstrap median inflection points below the 1/3 threshold, suggesting a possible nonlinear relationship between the vertical resorption proportion and three-dimensional changes. No statistically significant differences were observed in soft-tissue healing or implant-related outcomes. Histomorphometric evaluation of biopsy specimens showed new bone formation without signs of inflammation or fibrous encapsulation.

CONCLUSIONS

Within the limitations of this study, intentionally exposing the xenogeneic collagen matrix seal yielded comparable outcomes in non-contained and contained sockets. This finding may reflect the material's ability to reduce the adverse effects of socket-wall resorption; however, larger multicenter studies are warranted.

TRIAL REGISTRATION: Chinese Clinical Trial Registry Identifier: ChiCTR2300078331.