Mechanisms of degradation of collagen or gelatin materials (hemostatic sponges) in oral surgery: a systematic review

Objective: The goal of this systematic review was to identify the mechanisms associated with the enzymatic degradation of collagen and gelatin biomaterials and the possible associated flaws. Methods: Four databases (PubMed, B-On, Cochrane Library, and ResearchGate) were used for the bibliographic search of articles. The research question was formulated using the PCC method, (P): collagen or gelatin sponges, hydrogels, and scaffolds; concept (C): enzymatic degradation of collagen or gelatin sponges, hydrogels, and scaffolds; and context (C): effect of enzymatic action on degradation time of collagen or gelatin sponges, hydrogels, and scaffolds. The search was contextualized according to PRISMA recommendations. The identification and exclusion of evidence followed the PRISMA criteria, with specific inclusion and exclusion factors being stipulated for the selection of articles. The risk of bias assessment was performed using the QUIN Scale. Results: The initial search was composed of 13,830 articles after removing duplicates; 56 articles followed for the full-text reading; 45 were excluded; then, 11 articles were obtained, constituting the results of this systematic review. All studies evaluated the materials using gravimetric analysis, and collagenases were the proteases used for the degradation solution. The materials tested were as follows: humanlike collagen (HLC) hydrogel with microbial transglutaminase (MTGase), gelatin sponges subjected to different types of crosslinking, and collagen scaffolds with different types of crosslinking. The period of analysis varied between 0.25 h and 35 days. It was possible to highlight the lack of uniformity in the protocols used, which varied largely, thus influencing the degradation times. The risk of bias was low in nine studies and medium in two studies. Conclusions: This systematic review identified a gap in the literature, highlighting the absence of in vitro studies using human saliva and a collagenase concentration close to the physiological levels to simulate oral dynamics. However, based on existing literature, the mechanisms associated with collagen enzymatic degradation in collagen and gelatin biomaterials were comprehensively understood, answering the first research question postulated. In response to the second research question, the main shortcomings identified in the laboratory evaluation of mechanisms associated with collagen enzymatic degradation in collagen and gelatin biomaterials included the lack of standardization in degradation test protocols; this limited inter-study comparisons, which increased heterogeneity. Additionally, variations in collagenase concentrations and types influenced collagen degradation rates, and inappropriate evaluation intervals hindered the identification of total degradation time.