Lateral Ridge Augmentation Using Cross-Linked or Non-Cross- Linked Collagen Membrane: A Pilot Randomized Clinical Trial

Purpose: The aim of this investigation is to test, in a lateral ridge augmentation model without simultaneous implant placement, the effect of using a cross-linked collagen membrane and a non-cross-linked collagen membrane on guided bone regeneration. Material and Methods: Edentulous alveolar ridges of less than 5 mm width were treated with guided bone regeneration using a glutaraldehyde cross-linked collagen membrane (CL) or a non-cross-linked collagen membrane (NonCL). In all treated cases the bone graft used was a combination of autogenous bone scrapings and deproteinized bovine bone mixed in a 1:3 ratio. Ridge measurements were recorded clinically (during augmentation surgery and during implant placement surgery) and radiographically on the CBCT scans (pre-op, 1 week post-op and at implant placement). All ridge measurements were recorded at 1, 3 and 5 mm from the ridge crest. Soft tissue healing was assessed during the follow-up visits at 1, 2, 4, 8, 12, 16, 20 and 24 weeks post-op. A histological analysis was performed on core biopsies retrieved axially from implant or pontic sites. Results: Four patients were recruited and randomly allocated to treatment groups. Ridge width gain (RWgain) was significantly better for the CL group as assessed clinically. At 1, 3 and 5 mm from ridge crest, the clinically assessed gain was respectively 5.50 mm ± 2.121, 5.40 mm ± 2.074, 5.60 mm ± 1.140 for the CL group and -1.33 mm ± 0.577, 1.33 mm ± 2.517 and 2.00 mm ± 1.000 for the NonCL group. Graft volume resorption was significantly higher in the NonCL group (62%) in comparison to the CL group (10.9%). No soft tissue complications occurred during follow-ups in neither group. Histologically, both groups showed signs of bone remodeling and vital bone formation. New bone formation in the NonCL group was 23.64 % ± 0.64 and in the CL group was 15.75% ± 8.73. Conclusion: Despite the limitations of this pilot study, The CL membrane showed better performance than the NonCL membrane in terms of ridge width gain and in terms of graft volume consolidation as assessed clinically and radiographically. Although no statistical comparison was possible, the NonCL group presented a higher percentage of new bone formation than the CL group.