Long-term bio-degradation of cross-linked and non-cross-linked collagen barriers in human guided bone regeneration

Objective: This double-blind study clinically and histologically evaluated long-term barrier bio-durability of cross-linked and non-cross-linked collagen membranes (CLM and NCLM) in sites treated by guided bone regeneration procedures. Materials and methods: In 52 patients, 52 bony defects were randomly assigned to treatment with either a CLM or a NCLM. Post-surgical spontaneous membrane exposures were recorded. Before implant placement, full-thickness standard soft tissue discs were retrieved wherever suitable for histologic examination. Results: Spontaneous membrane exposure was observed in 13 (50%) CLM sites and in six (23.1%) NCLM sites (P < 0.05). Clinical healing at exposed sites lasted 2-4 weeks. CLM were histologically intact in all non-perforated sites, were interrupted in five perforated sites, and undetected in four. NCLMs were undetected in all 18 specimens examined. In three non-perforated CLM sites, bone apposition and ossification at or within the membrane was observed. Conclusions: CLMs were more resistant to tissue degradation than NCLMs, and maintained integrity during the study. Neither membrane was resistant to degradation when exposed to the oral environment. CLMs were associated with a higher incidence of tissue perforations. In non-perforated sites, CLM ossification at or within the membrane was occasionally observed.