Characterization of physical properties and histologic evaluation of injectable Dermicol-p35 porcine-collagen dermal filler.

BACKGROUND: Injectable dermal fillers have become important alternatives to traditional surgical procedures for the correction of facial wrinkles and restoration of facial volume. The physical properties of a dermal filler/volumizing agent, and the host tissue response to the agent, influence its clinical performance and patient outcomes. METHODS: In this study, several key physical properties of the new porcine collagen dermal filler Dermicol-P35 27G were measured and compared with those of commercially available hyaluronic acid-based dermal fillers. Furthermore, the in vivo properties of implanted Dermicol-P35 27G were evaluated by histologic and histopathologic methods. RESULTS: This study found that Dermicol-P35 27G provides a lower extrusion force profile and yield point compared with the hyaluronic acid-based dermal fillers tested. At 2 years, staining of punch biopsy specimens with hematoxylin and eosin and Herovici stains revealed no inflammatory cells and no evidence of other adverse events in any of the samples containing Dermicol-P35 27G. Within-implant colonization by fibroblasts depositing new collagen and the formation of elastin within the implanted collagen material (as shown by Luna staining) suggest that Dermicol-P35 27G is a bioactive implant. CONCLUSIONS: Compared with several hyaluronic acid-based dermal fillers, Dermicol-P35 exhibited lower extrusion force, higher viscosity under low shear rate, and a higher modulus of elasticity. Results of histologic evaluation indicated that Dermicol-P35 27G did not elicit an inflammatory response and was well integrated within the host tissue. Together, these results suggest that Dermicol-P35 27G offers several advantages that may result in improved clinical experiences for both patients and clinicians.

Ossification of a collagen membrane cross-linked by sugar: a human case series.

BACKGROUND: Collagen membranes cross-linked by glycation (GLYM) for guided bone regeneration (GBR) and guided tissue regeneration (GTR) are used extensively with proven safety and efficacy. Complete GLYM ossification, when placed in contact with bone, was described in a canine jaw model, suggesting that GLYM may serve as an ossification substrate. The purpose of this case series was to histologically evaluate GLYM in GBR procedures in humans. METHODS: We retrospectively selected seven consecutive patients with implant-related bony defects who underwent GBR with GLYM. Six defects had bone grafts, and one had a barrier alone. Selection criteria were primary closure upon post-surgical examination and tissue that was 2- to 3-mm thick over the implant's cover screw. Tissue was removed when the implants were uncovered after 20 to 29 weeks. Decalcified sections were stained and analyzed under light microscopy. RESULTS: In five of seven specimens, GLYM was identified and preserved its barrier effect. The mean membrane thickness was 0.17 +/- 0.054 mm. In two cases, the bone grafts under the membrane were embedded in new bone, whereas in five cases, they were embedded in fibrous connective tissue. Formation of new dense bone was observed along the side of the membrane facing the original bone, and various degrees of membrane ossification were evident in all five cases. CONCLUSIONS: GLYM maintained its barrier effect in five of seven cases for 25 weeks and induced dense new bone along its interface with underlying tissues. To the best of our knowledge, this is the first report on GLYM ossification in humans with direct mineral apposition on glycated collagen and suggests a new concept of tissue-integrated active barriers.

Long-term efficacy of a novel ribose-cross-linked collagen dermal filler: a histologic and histomorphometric study in an animal model.

BACKGROUND: Degradation and loss of the three-dimensional shape are the major causes of limited functional longevity of dermal fillers made of natural polymers as collagen and hyaluronic acid. OBJECTIVE: This study assessed the functional longevity of a new ribose-cross-linked collagen filler during 24 months in an animal model. METHODS: Ribose-cross-linked collagen (Evolence, Colbar Life Sciences Ltd), glutaraldehyde-cross-linked collagen (Zyplast, Inamed Inc.), and non-cross-linked collagen (Zyderm, Inamed Inc.) were injected in the rabbit ear dermis. Biopsies obtained at 1, 6, 12, and 24 months were histomorphometrically assessed for shape preservation and cell repopulation. RESULT: The three-dimensional shape of Evolence remained stable during 24 months. Zyderm and Zyplast lost their three-dimensional shape after 6 months. Although the cell density in Evolence remained stable over time, that in Zyplast and Zyderm decreased significantly at 12 and 24 months. CONCLUSION: Ribose-cross-linked collagen is endowed with a higher functional longevity as assessed in an animal model when compared with the most used collagen-based dermal fillers.

Ossification of a novel cross-linked porcine collagen barrier in guided bone regeneration in dogs.

BACKGROUND: Collagen membranes for guided bone regeneration (GBR) and guided tissue regeneration (GTR) are used extensively as bioabsorbable barriers. Cross-linking of collagen increases its biodurability and enables the control of its degradation kinetics and barrier function. A novel cross-linking technology was used to produce a porcine type I collagen membrane (GLYM). The purpose of this study was to evaluate the safety, efficacy, and degradation kinetics of GLYM compared to a non-cross-linked bilayer type I and III porcine collagen membrane (BCM) in surgically created defects in dogs. METHODS: After tooth extraction, two mandibular bilateral critical size defects were created in 12 beagle dogs that were randomly assigned to one of five groups: GLYM + bovine bone mineral (BBM), BCM + BBM, BBM alone, sham-operated, or GLYM alone. Dogs were euthanized after 8, 16, and 24 weeks, and sites were prepared for qualitative, semiquantitative, and quantitative light microscopy analyses. RESULTS: Membrane-protected sites displayed bone filling between the BBM particles with almost complete restoration of the original ridge morphology that increased with time up to 16 weeks and remained unchanged at 24 weeks. Both membranes showed marked degradation within 16 to 24 weeks, with BCM inconsistency that was undetectable in one of four sites at 8, 16, and 24 weeks. Membrane ossification was observed in all GLYM sites and in only one BCM site, which progressed with time to 24 weeks. Bone increased by approximately 1 mm on the lingual side, where the GLYM membrane was in direct contact with bone. CONCLUSIONS: Both membranes were safe and effective in supporting bone regeneration in critical size alveolar ridge defects in dogs and completely degraded within 24 weeks with marked BCM inconsistency. In areas of direct contact with bone, all GLYM sites were progressively ossified with time and augmented the original alveolar ridge. To the best of our knowledge, this is the first report of complete ossification of a collagen barrier membrane in GBR procedures.