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#### Abstract

Matrix-based therapy restoring the cell microenvironment is a new approach in regenerative medicine successfully treating human chronic pathologies by using a heparan sulfate mimetic (ReGeneraTing agents [RGTA]). Periodontitis are inflammatory diseases destroying the tooth-supporting tissues with no satisfactory therapy. We studied in vivo RGTA ability to fully restore the tooth-supporting tissues. After periodontitis induction, hamsters were treated with RGTA (1.5 mg kg(-1) w(-1)) or saline. Bone loss was evaluated and immunohistochemical labeling of molecules expressed during cementum development was performed. RGTA treatment restored alveolar bone and the attachment apparatus where fibers were inserted in acellular decorinnegative cementum. RGTA treatment increased the epithelial rests of Malassez, previously depleted by periodontitis.

Bone morphogenetic protein (BMP) expressions were compartmentalized: BMP-3 was strongly expressed by epithelial rests of Malassez; BMP-7 was expressed by cells lying on the cementum and BMP-2 by osteoprogenitors around bone formation sites but not at the root-bone interface. Cells near the cementum and bone expressed the ALK2 receptor. This is the first evidence that reconstructing the extracellular matrix scaffold with a heparan sulfate mimetic regenerated the root interface despite the persistence of the bacteria responsible for the disease The improved cellular microenvironment led to the sequential recruitment of cell populations involved in attachment apparatus regeneration.