Background and Objective Although previous studies revealed the potential use of probiotics in the control of periodontitis, little is known about their interactions with gingival epithelial cells (GECs). Since GECs comprise the first defense in the subgingival microenvironment, the aim of this study was to evaluate the effect of probiotic lactobacilli and bifidobacteria strains on OBA‐9 cells challenged with Porphyromonas gingivalis. Methods Immortalized human GECs (OBA‐9) were challenged with live P. gingivalis (strains W83 and ATCC33277) and co‐infected with one of 12 tested probiotic strains at a multiplicity of infection (MOI) of 1:1000 for 2 hours. Bacterial adhesion and invasion were determined by antibiotic exclusion analysis and CFU counting. OBA‐9 viability was assessed by MTT assay, and levels of inflammatory mediators (TNF‐α, IL‐1β, and CXCL8) in the supernatants were determined by ELISA. The expression of genes encoding Toll‐like receptors (TLR2, TLR4) was evaluated by RT‐qPCR. Results Both strains of P. gingivalis were able to adhere and invade OBA‐9 cells, with significant loss in cell viability, increase in the levels of TNF‐α and IL‐1β, and upregulation of TLR4. However, co‐infection with probiotics attenuated these effects in P. gingivalis challenged GECs. Most probiotics maintained OBA‐9 viability and reduced pathogens adhesion and invasion. Furthermore, probiotics were able to adhere to GECs, which was enhanced for most strains in the presence of P. gingivalis. The synthesis of IL‐1β and TNF‐α by P. gingivalis in challenged GECs was reduced in co‐culture with most of the tested probiotics, whereas the secretion of CXCL8 increased, and TLR4 was downregulated. Conclusion Probiotics can alter the interaction of GECs with P. gingivalis by modulating the pathogen's ability to adhere and invade these cells, as well as by regulating the innate immune response. Such properties are strain‐specific and may indicate the most efficient probiotics to control periodontitis.

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Background: Cell sheet technique using mesenchymal stem cells is a high-level strategy in periodontal regenerative medicine. Although recent studies have shown the role of MSCSs in increased dental supporting tissues and bone, there is not a systematic review focused specifically on assessing periodontal regeneration in orthotopic animal models. Objective: To evaluate the potential of mesenchymal stem cell sheets (MSCSs) on periodontal regeneration, compared to control, in experimental animal models. Methods: Pre-clinical studies in periodontal defects of animal models were considered eligible. The electronic search included the MEDLINE, Web of Science, EMBASE and LILACS databases. The review was conducted according to the Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement guidelines. Results: A total of 17 of the 3989 studies obtained from the electronic database search were included. MSCSs included dental follicle (DF) MSCSs, periodontal ligament (PL) MSCSs, dental pulp (DP) MSCSs, bone marrow (BM) MSCSs, alveolar periosteal (AP) MSCSs and gingival (G) MSCSs. Regarding cell sheet inducing protocol, most of the studies used ascorbic acid (58.82%). Others used culture dishes grafted with a temperature-responsive polymer (41.18%). Adverse effects were not identified in the majority of studies. Meta-analysis was not considered because of methodological heterogeneities. PDL-MSCSs demonstrated to be superior for periodontal regeneration enhancement compared to control, but in an induced inflammatory microenvironment, DF-MSCSs were better. Moreover, DF-MSCSs, DP-MSCSs, and BM-MSCSs showed improved results compared to control. Conclusion: MSCSs can improve periodontal regeneration in animal periodontal defect models.

Human periodontal ligament stem cells (PDLSCs) have been studied as a promising strategy in regenerative approaches. The protease-activated receptor 1 (PAR 1 ) plays a key role in osteogenesis and has been shown to induce osteogenesis and increase bone formation in PDLSCs. However, little is known about its effects when activated in PDLSCs as a cell sheet construct and how it would impact bone formation as a graft in vivo. Here, PDLSCs were obtained from 3 patients. Groups were divided into control, osteogenic medium and osteogenic medium + PAR 1 activation by TFLLR-NH2 peptide. Cell phenotype was determined by flow cytometry and immunofluorescence. Calcium deposition was quantified by Alizarin Red Staining. Cell sheet microstructure was analyzed through light, scanning electron microscopy and histology and transplanted to Balb/c nude mice. Immunohistochemistry for bone sialoprotein (BSP), integrin β1 and collagen type 1 and histological stains (H&E, Van Giesson, Masson’s Trichrome and Von Kossa) were performed on the ex-vivo mineralized tissue after 60 days of implantation in vivo . Ectopic bone formation was evaluated through micro-CT. PAR 1 activation increased calcium deposition in vitro as well as BSP, collagen type 1 and integrin β1 protein expression and higher ectopic bone formation (micro-CT) in vivo.