Dentistry and Dental Materials

Periodontitis is an inflammatory disease resulting from the presence of oral bacteria biofi lm in periodontal tissue, which destroys the tooth-supporting attachment apparatus. Untreated inflammation can spread to all periodontal tissue and lead, ultimately, to tooth loss. Guided tissue regeneration (GTR) is a technique based on a barrier membrane designed to prevent colonization of the wound space by gingival cells. Indeed, these cells, with a faster migration and proliferation rate compared to those of bone and periodontal ligament ones, could interfere with the regeneration process. We developed a photo-crosslinkable formulation composed on methacrylated carboxymethyl Chitosan (MA-CMCS) and silanized hydroxypropylmethyl cellulose (Si-HPMC), that can be applied in situ and cured with a visible light lamp (λ 420-480 nm), already used in dentistry. Photocuring, in fact, appears the more appropriate technique for this application for its both shape and curing time control. We assessed the chemical and physico-chemical profile of this material, showing a quick time to obtain a solid membrane. To evaluate the degradation, the crosslinked material was soaked in highly concentrated lysozyme buffer at 37°C. Si-HMPC/ MA-CMCS material revealed a degradation profile between the two crosslinked biomaterials of reference. The in vitro biocompatibility was demonstrated by Neutral red assay using murine fibroblast (L929). Moreover, we studied the barrier eff ect of using primary cells, human gingival fi broblasts, observing the cells by confocal microscopy. No cells invasion was observed in Si-HMPC/MA-CMCS material. In addition, we set up an ex vivo experiment culturing human gingival explants in  presence of our biomaterial and using pullulan porous material as a negative control. After culture, the samples were stained with hematoxylin, eosin Y and safranin (HES). The histological sections revealed that the biomaterial exhibited the barrier eff ect in contact with soft  tissue. In the next future, in vivo experiment will be performed to further characterize the material for periodontal regeneration.