Evaluation of enamel matrix derivative used alone or added to collagen membrane for tissue repair: in vivo animal study using a rat dorsal wound model

Gingival biotype is decisive for the outcome of rehabilitation treatments, and its impact on therapeutic prognosis is directly related to tissue fragility and marginal tissue recessions. This study aimed to evaluate the effect of enamel matrix derivative (EMD) and porcine collagen matrix, alone or combined, on wounds made on the rat dorsum. Wounds were created in the dorsum of 40 Wistar rats divided into 4 sample groups: G1 = clot, G2 = porcine collagen matrix (Straumann^® Mucoderm^®), G3 = enamel matrix derivative (EMD, Emdogain^®), G4 = porcine collagen matrix (Straumann^® Mucoderm^®) and EMD (Emdogain^®). The animals were euthanized on days 7 and 14, and their wound was evaluated histologically to assess wound closure and re-epithelialization, and to measure tissue inflammation. At 7 days, groups treated with EMD (G3 and G4) exhibited significantly lower inflammation scores compared to G1 and G2 (p < 0.05). At 14 days, all groups showed complete wound closure with no significant differences in inflammatory scores. However, G3 demonstrated a markedly greater epithelial thickness, with epithelial projections into the underlying connective tissue and evidence of keratin formation. Collagen fiber organization was also more evident in G3 and G4. Therefore, porcine collagen matrix, whether alone or combined, promoted tissue regeneration, and the combination of these substitutes with EMD, resulted in less tissue inflammation and greater epithelial thickness. These advantages emphasize their use for soft tissue augmentation and improvement.