It was reported that postnatal stem cells are present in adult tissues such as bone marrow, liver, muscle, dental pulp, and periodontal ligament. We isolated postnatal stem cells from human dental tissues such as dental pulp (DPSC), periodontal ligament (PDLSC), periapical follicle (PAFSC), and the surrounding mandibular bone marrow (MBMSC) to ascertain their properties. Immunocytochemistry proved the existence of stem cells in these cell populations using STRO-1 as a stem cell marker. These cells also expressed the mesenchymal stem cell (MSC) markers CD29 and CD44. The isolated cells showed self-renewal capabilities and colony-forming efficiency. Almost all of the dental stem cells showed optimal growth when they were cultured in alpha modification of Eagle's medium (alpha-MEM) supplemented with 10% fetal calf serum (FCS) and 100 microM ascorbic acid. Only the PAFSC showed increased proliferation in 20% FCS and 50 microM ascorbic acid. All of the dental stem cells were capable of differentiating into adipocytes and mineral nodule forming cells. MBMSC, in particular, showed much better mineralization compared to the others. These results indicate that MSCs exist in various tissues of the teeth and can differentiate into osteoblasts, adipocytes, and other kinds of cells with varying efficiency.

The platelet-rich fibrin (PRF) is known as a rich source of autologous cytokines and growth factors and universally used for tissue regeneration in current clinical medicine. However, the microstructure of PRF has not been fully investigated nor have been studied the key molecules that differ PRF from platelet-rich plasma. We fabricated PRF under Choukroun's protocol and produced its extract (PRFe) by freezing at À808C. The conventional histological, immunohistological staining, and scanning electron microscopy images showed the microstructure of PRF, appearing as two zones, the zone of platelets and the zone of fibrin, which resembled a mesh containing blood cells. The PRFe increased proliferation, migration, and promoted differentiation of the human alveolar bone marrow stem cells (hABMSCs) at 0.5% concentration in vitro. From the results of proteome array, matrix metalloproteinase 9 (MMP9) and Serpin E1 were detected especially in PRFe but not in concentrated platelet-rich plasma. Simultaneous elevation of MMP9, CD44, and transforming growth factor b-1 receptor was shown at 0.5% PRFe treatment to the hABMSC in immunoblot. Mineralization assay showed that MMP9 directly regulated mineralization differentiation of hABMSC. Transplantation of the fresh PRF into the mouse calvarias enhanced regeneration of the critical-sized defect. Our results strongly support the new characteristics of PRF as a bioscaffold and reservoir of growth factors for tissue regeneration.

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The association between oral squamous cell carcinoma (OSCC) and periodontitis in large hospital cases with cohort controls has yet to be evaluated. The aim of this study was to investigate the association of periodontitis with OSCC across tumor location and tumor-node-metastasis (TNM) stage among Koreans ( N = 424). OSCC cases ( n = 146) were recruited from Seoul National University Dental Hospital and matched by age, sex, and smoking to controls ( n = 278) from the Yangpyeong health and periodontal cohort in Korea. OSCC was diagnosed through biopsy and radiographs, including computed tomography and magnetic resonance imaging. Tumor location and TNM stage were classified after the surgery. Periodontitis was defined by alveolar bone loss with panoramic radiographs following the guidelines of the Fifth European Workshop in Periodontology. Alcohol intake, education, physical activity, obesity by body mass index, hypertension by blood pressure, diabetes by plasma glucose, and hypercholesterolemia by plasma cholesterol were considered as confounders. Information about age, sex, smoking, alcohol intake, education, and physical activity was obtained through interview; body mass index and blood pressure, through physical examination; and preoperative glucose and cholesterol, through laboratory tests. Bivariate analysis was applied with Fisher’s exact chi-square test. Multivariable conditional logistic regression models were applied to evaluate the adjusted association of periodontitis with OSCC after controlling for confounders. Subgroup analyses were explored by OSCC and periodontitis. Participants with periodontitis were 3.7 times more likely to have OSCC (adjusted odds ratio [aOR] = 3.66, 95% CI = 1.46 to 9.23) than participants without periodontitis. The differences in periodontitis were not statistically significant across TNM stages of OSCC ( P > 0.05) and its location ( P > 0.05). The link was highlighted among males (aOR = 6.55), elders aged >60 y (aOR = 4.98), and those with more tooth loss (aOR = 9.99). Our data showed that periodontitis was independently associated with OSCC. Thus, the risk of OSCC could be modulated by reducing periodontitis.