Periodontal disease is a major public health issue, and various periodontal therapies have been performed to regenerate periodontal tissues. The periodontium is a complex structure composed of specialized tissues that support the teeth, and most periodontal surgeries are invasive procedures, including a resection of the gingiva or the alveolar bone. The periodontal wound healing process is slightly different from cutaneous wound healing and is similar to fetal healing, being almost scar-free. The aim of this review article is to provide an overview of periodontal wound healing and discuss various surgical and pharmaceutical approaches to achieve stable wound healing and improve the treatment outcomes. In addition, detrimental and limiting factors that induce a compromised prognosis are discussed, along with the perspective and future direction for successful periodontal tissue regeneration.

Background: Chitosan is known as a biodegradable and non‐toxic natural polymer that enhances wound healing and bone formation. The aims of this study are to evaluate the biocompatibility of chitosan nanofiber membranes and to examine the effect of the chitosan nanofiber membranes on bone regeneration in rabbit calvarial defects.Methods: In vitro cell proliferation tests using human osteosarcoma cell line MG63 and reverse transcription‐polymerase chain reaction (RT‐PCR) to evaluate the expression of alkaline phosphatase (ALP), collagen, osteocalcin (OCN), and GAPDH were done on chitosan nanofiber membranes. Chitosan nanofiber membranes were implanted in subcutaneous connective tissue and observed for 2, 4, and 6 weeks in rats. Ten‐millimeter diameter round cranial defects were made in rabbits and covered by chitosan nanofiber membranes for 4 weeks. Specimens were decalcified and observed by a light microscope.Results: MG63 cells proliferated for 28 days on the chitosan nanofiber membranes and expressed ALP, collagen, OCN, and GAPDH at 2 weeks. Chitosan nanofiber membranes that were grafted into rat subcutaneous tissue maintained their shape and space for bone regeneration for as long as 6 weeks. No inflammation could be seen on the membrane surface or in the surrounding tissues. In the rabbit calvarial defects, new bone filled the defects and fused to the original old bone in 4 weeks.Conclusions: The biocompatibility of the chitosan nanofiber membrane was confirmed, with enhanced bone regeneration and no evidence of an inflammatory reaction. This experiment shows that the novel biodegradable chitosan nanofiber membrane may be useful as a tool for guided bone regeneration.

Background: The present study was undertaken to evaluate the potential of periodontal ligament stem cells (PDLSCs) and bone marrow SCs (BMSCs) on alveolar bone regeneration in a canine peri‐implant defect model.Methods: Four adult, male beagle dogs were used in this study. Autologous BMSCs from the iliac crests and PDLSCs from extracted teeth were cultured. Three months after extraction, BMSC‐ and PDLSC‐loaded hydroxyapatite/β‐tricalcium phosphate (HA/TCP) (test groups) and cell‐free HA/TCP (control group) were implanted in three rectangular, saddle‐like peri‐implant defects, respectively. The left side of the mandible was initially prepared, and after 8 weeks, the right side was also prepared. The animals were sacrificed after an 8‐week healing period. Undecalcified ground sections were prepared. New bone formation and bone‐to‐implant contact (BIC) were measured histomorphometrically. BMSCs and PDLSCs were fluorescently labeled and traced.Results: Alveolar bone regeneration in surgically created peri‐implant saddle‐like defects was more effective in test groups than the control group. The BMSC group had the highest new bone formation (34.99% and 40.17% at healing times of 8 and 16 weeks, respectively) followed by the PDLSC group (31.90% and 36.51%) and control group (23.13% and 28.36%), respectively. Test groups exhibited a significantly higher new bone formation than the control group at 8 weeks, but the same was true for only the BMSC group at 16 weeks (P <0.05). Fluorescently labeled cells were identified adjacent to HA/TCP carriers and, partly, near connective tissues and osteoids.Conclusion: This study demonstrated the feasibility of using stem cell–mediated bone regeneration to treat peri‐implant defects.

Magnolol (1) and honokiol (2), main compounds from the stem bark of Magnolia obovata Thunb., were evaluated for an antimicrobial activity against periodontopathic microorganisms, Porphyromonas gingivalis, Prevotella gingivalis, Actinobadllus actinomycetemcomitans, Capnocytophaga gingivalis, and Veillonella disper, and a cytotoxicity against human gingival fibroblasts and epithelial cells. Our results indicate that magnolol and honokiol, although less potent than chlorhexidine, show a significant antimicrobial activity against these microorganisms, and a relatively low cytotoxic effect on human gingival cells. Thus, it is suggested that magnolol and honokiol may have a potential therapeutic use as a safe oral antiseptic for the prevention and the treatment of periodontal disease.