in Group 1; (3) CS challenge (50N occlusal load, 30 s occlusal time plus 30 s with no load, for 30 days); (4) pre-treatment with 0.5M EDC as in Group 2 and CS challenge as in Group 3. After aging, sampleswere prepared for SEMandmicroanalysis characterization by means of EDS probe. Results: Fig. 1 reports the results of the SEM and EDS analyses. Samples treated with EDC aged in both CS (Fig. 1a) and Static (Fig. 1b) conditions demonstrate a more compact structure if compared to samples without treatment (Fig. 1c and d). In addition, EDS analyses revealed the persistence of chlorine element of samples treated with EDC in both CS (Fig. 1e) and static conditions (data not shown). Conclusion: EDC-treated collagen exhibits a compact structure probably related to higher stability of the matrix. The presence of chlorine in EDC treated samples led to conclude that cross-linking treatment is stable also after 30 days of aging.