Objectives Periodontitis and rheumatoid arthritis (RA) are chronic inflammatory diseases characterized by progressive tissue destruction, and numerous studies have suggested that they are linked. However, the molecular mechanisms underlying this association remain unclear. The aim of this study was to identify molecular pathways beyond classical inflammation and immunity that are commonly dysregulated in periodontitis and RA. Methods We performed in silico screening of publicly available transcriptomic datasets for periodontitis and RA. Next, we performed experimental validation of candidate molecules in an in vitro culture model designed to mimic periodontal tissue under RA-associated conditions. Results Comparative analyses of healthy controls identified 540 differentially expressed genes (DEGs) in periodontitis, 4019 DEGs in RA, and 117 commonly upregulated DEGs. Among these, CHI3L2 and MMP3 were selected for further investigation and were found to be prominently expressed in gingival fibroblasts. Quantitative real-time polymerase chain reaction analyses showed that both genes were significantly upregulated by lipopolysaccharide stimulation and by conditioned medium derived from RA synovial cells, with a synergistic enhancement observed when both stimuli were applied simultaneously. Co-culture and wound-healing assays showed that RA synovial cells impaired proliferation and migration of gingival fibroblasts. Conclusions RA-associated pathological factors may influence the responsiveness of periodontal tissue to inflammatory stimuli. Although periodontitis and RA are primarily driven by immune-mediated inflammation, tissue-level molecular expression and sensitivity to stimulus may also be altered, providing complementary insights into shared disease mechanisms and their potential relevance for clinical management.

BACKGROUND:The aim of this case series was to introduce intraoral Er:YAG laser-assisted de-epithelialization of autogenous gingival graft (EL-DGG) for root coverage and alveolar ridge augmentation. METHODS:In conventional harvesting of de-epithelialized gingival grafts (DGGs) with a scalpel, the presence of residual epithelium has occasionally been observed, posing challenges to the reliable procurement of stable connective tissue grafts (SCTG). We utilized an Er:YAG dental laser, known for its minimal histological effect among dental lasers, to perform intraoral DGG in three cases involving root coverage or ridge augmentation. RESULTS:Complete root coverage was achieved in the two root coverage cases. In the ridge augmentation case, horizontal and vertical dimensional gains of 1.56 and 0.74 mm, respectively, were observed. A portion of the CTG obtained from the peripheral trimmed area was biopsied and histologically examined. De-epithelialization of this area was performed using the same protocol as in the clinical procedure, including both Er:YAG laser irradiation and adjunctive rotary brush application, suggesting that epithelial removal was achieved in the examined sample with minimal damage to the underlying connective tissue layer of dense collagen fibers. CONCLUSIONS:By effectively eliminating epithelial remnants and preserving connective tissue thickness in palatal grafts, EL-DGG can offer more favorable clinical outcomes in root coverage and ridge augmentation compared to conventional graft-harvesting methods. KEY POINTS:Selective epithelial removal: Intraoral Er:YAG laser-assisted de-epithelialization enables selective removal of palatal epithelium while preserving dense subepithelial connective tissue thickness. Histologic and clinical validation: Histologic analysis confirmed complete epithelial elimination with minimal lamina propria damage, resulting in stable root coverage and soft tissue augmentation. Advantage in thin phenotypes: This technique allows predictable graft harvesting even in thin palatal mucosa, supporting phenotype modification and ridge augmentation procedures. PLAIN LANGUAGE SUMMARY:Gum tissue taken from the roof of the mouth is commonly used to cover exposed tooth roots or rebuild areas where soft tissue has been lost. However, when preparing these grafts with a scalpel, small remnants of the surface epithelial layer may remain, while removing too much tissue can reduce the thickness and quality of the connective tissue needed for treatment. In this case series, we used an Er:YAG laser to remove the epithelial layer directly from the palate before harvesting the graft. This approach was used in three patients: two received treatment for exposed tooth roots, and one received soft tissue augmentation in an area with a missing tooth. Complete root coverage was achieved in both root coverage cases, and an increase in tissue volume was observed in the ridge augmentation case. Microscopic examination of a graft sample suggested that the epithelial layer was removed while the dense connective tissue underneath was largely preserved. These findings suggest that Er:YAG laser-assisted graft preparation may help clinicians obtain thick, stable connective tissue grafts while reducing unwanted epithelial remnants. Further studies involving more patients and longer follow-up are needed to confirm these potential benefits.

The purpose of this study was to longitudinally investigate the hemoglobin (Hb) test in gingival crevicular fluid of periodontitis patients, together with clinical parameters (plaque index: PlI, probing depth: PD, clinical attachment level: CAL, bleeding on probing: BOP, and gingival index: GI) during two-year supportive periodontal therapy (SPT). A total of 191 periodontal sites in 91 patients during the SPT period were clinically and biochemically evaluated three times (first, second, and third examinations) over two years. After the first examination of the clinical and biochemical parameters, periodontal support treatments were administered and then repeated every three months until the third examination. The values of PD, CAL, GI, and Hb decreased from the first examination to the second or third examination. Notably, the percentage reduction of Hb test values was significant. However, only the BOP value tended to increase. The decreases in these clinical and biochemical parameters suggested that the periodontitis was not exacerbated, but rather tended to recover with periodontal treatment. These reductions in PD, CAL, and Hb values from the first examination were clearly more common in the PD ≥ 5 mm group than in the PD ≤ 4 mm group for all test sites. In this study, the highly sensitive Hb test showed that periodontal treatment for two years suppressed the progression of periodontitis. This trend was significant in the deep gingival sulcus (PD ≥ 5 mm) group, suggesting that the Hb test may be a useful quantitative marker to predict recurrence of periodontitis.

Despite the well-established bidirectional relationship between periodontal disease and diabetes, limited research has examined the role of regular dental check-ups in patients with type 2 diabetes. This study analyzed the relationship between periodontal disease status, dental visit patterns, and diabetes status using baseline data from the Japan Diabetes Complication and its Prevention (JDCP) prospective study. Among 6,099 patients with diabetes (aged 40–75 years), 685 with type 2 diabetes who underwent dental examinations were included. Trained dentists collected periodontal disease data using self-report questionnaires and periodontal examination.Insulin resistance was evaluated using the homeostasis model assessment of insulin resistance (HOMA-IR). Participants who did not undergo regular dental check-ups exhibited higher HOMA-IR values than those who did. Logistic regression analyses revealed a significant association between insulin resistance and regular dental check-ups (odds ratio = 2.33, 95% confidence interval = 1.07–5.09, P = 0.034). Approximately 50% of the respondents did not undergo regular dental check-ups. Individuals who undergo dental check-ups may experience improved local periodontal inflammation through treatment, potentially reducing systemic inflammation and infection compared to those who do not. This reduction in systemic inflammation and infection could contribute to improved insulin resistance.

Periodontal inflamed surface area (PISA) and masticatory efficiency have been used to evaluate the relationship between systemic diseases and oral diseases. However, clear standards for PISA values and masticatory efficiency in relation to the severity of periodontitis are lacking. This study aims to evaluate PISA values and masticatory efficiency based on the 2018 periodontal status classification system. In total, 153 healthy participants diagnosed with periodontitis were included in the study. The diagnosis was based on the 2018 periodontal status classification. PISA values and masticatory efficiency were measured at baseline and after initial periodontal therapy. PISA demonstrated a higher area under the curve for Stage III (0.815) and Grade B (0.85). At baseline, PISA was showed significant negative correlation with masticatory efficiency (B coefficient [95

Osteoclasts are hematopoietic cells attached to the bones containing type I collagen-deposited hydroxyapatite during bone resorption. Two major elements determine the stiffness of bones: regular calcified bone (bone that is resorbable by osteoclasts) and un-calcified osteoid bone (bone that is un-resorbable by osteoclasts). The osteolytic cytokine RANKL promotes osteoclast differentiation; however, the roles of the physical interactions of osteoclasts with calcified and un-calcified bone at the sealing zones and the subsequent cellular signaling remain unclear. In this study, we investigated podosomes, actin-rich adhesion structures (actin-ring) in the sealing zone that participates in sensing hard stiffness with collagen in the physical environment during osteoclast differentiation. RANKL-induced osteoclast differentiation induction was promoted when Raw264.7 cells were cultured on collagen-coated plastic dishes but not on non-coated plastic dishes, which was associated with the increased expression of podosome-related genes and Src. In contrast, when cells were cultured on collagen gel, expression of podosome-related genes and Src were not upregulated. The induction of podosome-related genes and Src requires hard stiffness with RGD-containing substratum and integrin-mediated F-actin polymerization. These results indicate that osteoclasts sense both the RGD sequence and stiffness of calcified collagen through their podosome components regulating osteoclast differentiation via the c -Src pathway.

AimDiabetes is a significant risk factor that exacerbates the pathological progression of periodontal disease. In recent years, attention has focused on the effect of regulatory T cells (Tregs), which play a central role in immune tolerance, on inflammatory processes in periodontal tissue, suggesting a link with diabetes-associated periodontitis. In this study, we examined the dynamics of Tregs in periodontal tissue of mice with streptozotocin (STZ)-induced hyperglycemia.MethodsEleven-week-old male C57BL/6J mice were divided into four treatment groups: Untreated (C group), ligature placed around the maxillary second molars with silk sutures (PD group), intraperitoneal administration of STZ (HG group), and ligature placed after STZ administration (PHG group). Establishment of hyperglycemia was assessed 14 days after STZ administration, and ligation was performed 7 days later. After another 7 days of ligation, the mice were euthanized. The right side of the maxilla was observed histopathologically, whereas the palatal gingiva on the left side of the maxilla was analyzed genetically, and the microstructure of the alveolar bone was also assessed. In addition, lymphocytes from peripheral blood, spleen, and periodontal tissue were analyzed using flow cytometry.ResultsIn bone structure analyses, alveolar bone height, bone volume/tissue volume (BV/TV), and bone mineral density (BMD) were lower in the PHG group than the PD group. In the gingival tissue, expression of the Foxp3 gene was up-regulated in the PHG group compared with the C group, and IL-17a was up-regulated in the PHG group compared with the PD group. Flow cytometry analyses showed that the number of Tregs (CD4+CD25+Foxp3+ cells) in the blood and gingival tissue was significantly higher in the PD and PHG groups than the C group. The number of CD4+CD25-Foxp3+ cells, which are reportedly functionally attenuated as Tregs, was increased in blood of the PHG group. Immunofluorescence staining of periodontal tissue showed that the number of CD25+Foxp3+ cells was significantly increased only in the PD group, whereas a trend toward an increased number of CD25-Foxp3+ cells was observed in the PHG group.ConclusionThe present study showed that STZ-induced hyperglycemia numerically and functionally attenuates Tregs in a mouse model of experimental periodontitis. Furthermore, impaired immune tolerance capacity appears to be involved in exacerbating inflammation and bone destruction in periodontal tissue.

Objective: The purpose of this study was to verify the accuracy and utility of clinical parameters (plaque index, gingival crevicular fluid volume, probing depth, clinical attachment level, bleeding on probing and gingival index) and biochemical parameters (aspartate aminotransferase, protein and haemoglobin) in a longitudinal analysis during the supportive periodontal therapy period.Subjects and Methods: A total of 279 test sites of 128 patients were investigated clinically and biochemically. After the first examination of clinical and biochemical parameters, periodontal support treatments were administered immediately and per-formed once every three months up to the second examination.Results: All of the clinical and biochemical parameters were significantly lower at the second examination than at the first, except for the plaque index and bleeding on probing. Of these parameters, in particular, aspartate aminotransferase and haemoglobin in the gingival crevicular fluid were significantly reduced compared to those of the first examination in both the <= 4 and >= 5 mm probing depth groups, and they clearly suggested that periodontitis tended to recover.Conclusion: Adding the haemoglobin test to the bleeding on probing test strongly improves the accuracy of measurement of clinical parameters after periodontal treatment.

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis , to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis , Treponema denticola , Tannerella forsythia and Fusobacterium nucleatum , were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin’s ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

BACKGROUND: We determined the effects and an accurate marker of periodontal treatment on serum interleukin (IL) -6 and high -sensitivity C -reactive protein (HsCRP) levels in systemically healthy individuals with periodontal disease. METHODS: This multicenter study included systemically healthy individuals with periodontal disease who received initial periodontal treatment and had no periodontal treatment history. Periodontal parameters, including periodontal inflamed surface area, masticatory efficiency, and periodontal disease classification; serum IL -6 and HsCRP levels; and serum immunoglobulin (Ig)G titers against periodontal pathogens were evaluated at baseline and after treatment. Subjects were classified as low or high responders (group) based on periodontal inflamed surface area changes. RESULTS: There were 153 participants. Only periodontal inflamed surface area changes were markedly different between low and high responders. Periodontal treatment (time point) decreased both serum IL -6 and HsCRP levels. The interaction between group and time point was remarkable only for serum IL -6 levels. Changes in serum immunoglobulin (Ig)G titers against periodontal pathogens were not associated with IL6 changes in high responders. We analyzed the indirect effect of serum anti-Porphyromonas gingivalis type 2 IgG titer changes using mediation analysis and found no significance. However, the direct effect of group (low or high responder) on IL -6 changes was considerable. CONCLUSIONS: Periodontal treatment effectively decreased serum IL -6 levels, independent of periodontal pathogen infection, in systemically healthy individuals with periodontal disease. (c) 2023 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) center dot The American Journal of Medicine (2024) 137:273-279

日本歯周病学会会員の職種別喫煙状況や禁煙支援の現状とその関連要因を明らかにするため,2022年時の会員にweb質問票調査を実施した。解析対象は1,396名(回収率11.2%)で,喫煙状況は,非喫煙者945名(67.7%),前喫煙者414名(29.6%),喫煙者37名(2.7%)となった。なお,喫煙者の内訳は,紙巻きタバコ単独13名(35.1%),加熱式タバコ(HTP)単独15名(40.5%),水タバコ単独1名(2.7%),紙巻きタバコとHTPの併用4名(10.8%),HTPの併用3名(8.1%),紙巻タバコと電子タバコの併用1名(2.7%)であった。次に,歯周病患者に対する禁煙支援は,すべての患者に実施240名(18.3%),必要時に実施656名(50.1%)であった。さらに,禁煙支援の関連要因は,歯科医師では,50歳以上,KTSND得点規準範囲9点以下,重度歯周病との関連を認識している者の3要因が関連していた(P < 0.05)が,歯科衛生士では有意な関連要因がみられなかった。したがって,歯科医師は,喫煙に対する正しい知識を持つ者がより禁煙支援を実施していた。このことから,禁煙支援の知識や正しい認識の普及等の啓発により,歯科医療職の禁煙支援実施率の向上をめざし,禁煙支援を行いやすい環境を作ることが急務であると考えた。

A growing body of evidence from multiple areas proposes that periodontal disease, accompanied by oral inflammation and pathological changes in the microbiome, induces gut dysbiosis and is involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). A subgroup of NAFLD patients have a severely progressive form, namely nonalcoholic steatohepatitis (NASH), which is characterized by histological findings that include inflammatory cell infiltration and fibrosis. NASH has a high risk of further progression to cirrhosis and hepatocellular carcinoma. The oral microbiota may serve as an endogenous reservoir for gut microbiota, and transport of oral bacteria through the gastro-intestinal tract can set up a gut microbiome dysbiosis. Gut dysbiosis increases the production of potential hepatotoxins, including lipopolysaccharide, ethanol, and other volatile organic compounds such as acetone, phenol and cyclopentane. Moreover, gut dysbiosis increases intestinal permeability by disrupting tight junctions in the intestinal wall, leading to enhanced translocation of these hepatotoxins and enteric bacteria into the liver through the portal circulation. In particular, many animal studies support that oral administration of Porphyromonas gingivalis, a typical periodontopathic bacterium, induces disturbances in glycolipid metabolism and inflammation in the liver with gut dysbiosis. NAFLD, also known as the hepatic phenotype of metabolic syndrome, is strongly associated with metabolic complications, such as obesity and diabetes. Periodontal disease also has a bidirectional relationship with metabolic syndrome, and both diseases may induce oral and gut microbiome dysbiosis with insulin resistance and systemic chronic inflammation cooperatively. In this review, we will describe the link between periodontal disease and NAFLD with a focus on basic, epidemiological, and clinical studies, and discuss potential mechanisms linking the two diseases and possible therapeutic approaches focused on the microbiome. In conclusion, it is presumed that the pathogenesis of NAFLD involves a complex crosstalk between periodontal disease, gut microbiota, and metabolic syndrome. Thus, the conventional periodontal treatment and novel microbiome-targeted therapies that include probiotics, prebiotics and bacteriocins would hold great promise for preventing the onset and progression of NAFLD and subsequent complications in patients with periodontal disease.

In implant treatment, the reduction and structural changes in the alveolar ridge that occur after tooth extraction limit the length, width, and placement position of the implant body, impair esthetics, and, in some cases, make implant placement difficult. To solve these problems, an alveolar ridge preservation (ARP) technique, which is performed simultaneously with tooth extraction, generally aims to promote bone regeneration and prevent alveolar ridge reduction by filling the extraction socket with bone graft material and then covering it with a barrier membrane to protect against the invasion of epithelial tissue. The extraction socket provides a favorable environment for bone regeneration throughout the healing period because the blood supply is abundant, and it effectively retains the bone graft material by using the remaining bone wall of the socket. In recent years, advances in bioengineering technology have led to the development of graft materials with various biological properties, but there is currently no clear consensus regarding the selection of surgical techniques and materials depending on the condition of the alveolar ridge. This review will provide a comprehensive survey of the evidence accumulated to date on ARP, present many cases according to the clinical situation, and discuss various treatment options.

Purpose: Recently, low reactive level laser therapy (LLLT) has been attracting attention in periodontal treatment. However, little is known about the response to irradiation of gingival epithelial cells, which constitute gingival tissue and are directly affected by laser light in the superficial layer. In this study, we determined the ideal laser irradiation conditions and analyzed the temporal expression of relevant genes to investigate the effect of LLL irradiation on wound healing in human gingival epithelial cells. Methods: Immortalized human gingival epithelial cells (HGK) were seeded at 2.5×103 cells per well, cultured for 24hours. After incubation for 24hours, the cells were irradiated with lasers of 0.5, 1, 2, 3, 4, 5, and 6W, with no laser irradiation as a control. After laser irradiation, the cell proliferation rate was measured using WST-8, which is a method offering improvement over the MTT assay. Irradiation was performed under the laser irradiation conditions determined from cell proliferation measurement results. Then, qRT-PCR analysis was used to compare the temporal expression of wound healing-related genes (EGF, EGFR, TGF-α, and HB-EGF) at 1, 3, 6, 12, and 24 hours after laser irradiation. Results: A significant increase in cell proliferation rate was observed in the 3 W laser irradiated group on days 2 and 3 after laser irradiation, compared to the control. Based on the above, the ideal laser irradiation condition for HGK in this study was determined to be 3W (100mJ, 30pps, 10s). Gene expression analysis showed significant upregulation of EGFR and TGF-α at 6 hours and HB-EGF at 12 hours after laser irradiation compared to the control. Discussion and Conclusion: The results of this study showed that LLL irradiation of HGK promoted cell proliferation and increased the expression of wound healing-related genes. LLL irradiation might promote wound healing of the gingival epithelium in vitro.

The purpose of this study was to evaluate the periodontal status of patients who routinely did SPT, when compared to patients that did not SPT. This retrospective cohort study was conducted at a general dental office from 2001 to 2019. Patients aged 18 to 81 years who visited the dental office over a 10-year period were assigned into two groups: an SPT group, which included patients who continually visited the dental office for SPT one or more times every year, and an irregular group, consisting of patients who did not visit the dental office at least once a year. A total of 7307 teeth (SPT group) and 4659 teeth (irregular group) were evaluated, and the periodontal conditions were compared between the first and latest visits. Multiple regression analysis was used to analyze the results. The mean follow-up time was 13.74 years. The risk factors for improvements in probing pocket depth included age, sex, smoking, diabetes mellitus, molar tooth, and irregular SPT group (p < 0.001), and that for a positive bleeding on probing site was the irregular group (odds ratio 2.94; 95

There has been emerging data and a growing appreciation of the negative effects of periodontal disease on nonalcoholic fatty liver disease (NAFLD), which is currently the most prevalent chronic liver disease worldwide. A subgroup of these NAFLD patients develops more severe and progressive forms of liver disease, namely, nonalcoholic steatohepatitis (NASH), which are a risk for developing cirrhosis and hepatocellular carcinoma. In this review, we will summarize the recent epidemiological, basic, and clinical research findings on the relationship between periodontal disease and NAFLD/NASH and discuss the pathogenesis of NAFLD/NASH and potential new treatment options with a particular focus on the gut microbiota. In terms of the mechanism by which harmful factors are transported from diseased periodontal tissue to the liver, two routes of transmission have been proposed based on the unique anatomical characteristics of the liver, namely, through a hematogenous diffusion via the systemic circulation and through a gut–liver axis via the gastrointestinal tract. In particular, with respect to enteral diffusion, gut microbiome dysbiosis induced by enteral translocation of periodontopathic bacteria may be involved in NAFLD. In terms of a gut–liver axis, one mechanism assumed to link the gut microbiome to NAFLD is the disruption of the gut epithelial barrier, which may allow leakage of microbial products and metabolites into the portal circulation. Namely, changes in lipopolysaccharide and bacterial metabolites due to gut dysbiosis can induce intestinal inflammation and increase permeability, thereby promoting hepatic exposure to these components, which can directly cause NAFLD and liver fibrosis. Porphyromonas gingivalis, a common periodontopathic bacteria, may be involved in the pathogenesis of both the gut dysbiosis and NAFLD via several different pathways. Therefore, diverse strategies for manipulating the gut microbiome in the management of NAFLD related to periodontal disease have been proposed, including the use of antibiotics, probiotics, and prebiotics. Despite research limitations, there is a large body of evidence supporting the relationship between periodontal disease and NAFLD/NASH. The importance of the oral–gut–liver axis in the pathogenesis of NAFLD is increasing, and future research on microbiome-targeted therapy to improve periodontal disease-related gut dysbiosis is warranted.

Background: Necrotizing periodontitis (NP) is a reactive and destructive inflammatory process that occurs in response to bacterial infection. Predisposing factors such as compromised host immune responses contribute significantly to NP pathogenesis. NP occasionally progresses to a more advanced and life-threatening state. Case presentation: A 73-year-old man in need of nursing care visited our dental clinic with severe gingival pain and intraoral bleeding. He had a disability and was immunocompromised because his medical history included cerebral infarction and type 2 diabetes mellitus. He was diagnosed with NP based on his typical symptoms, such as prominent bleeding and suppurative discharge from the gingiva, in addition to crater-shaped ulcerations of the interdental papillae. To improve daily oral hygiene, periodontists, dentists, and dental hygienists educated care workers and other staff at the nursing home on appropriate oral cleansing, including brushing three times a day using the Bass technique. Basic periodontal therapy, including whole-mouth scaling and debridement of the root surfaces using hand and ultrasonic instruments, was also performed. After this basic treatment of NP, we extracted the hopeless teeth. Currently, dentists visit the patient fortnightly to manage his oral hygiene. To date, good oral health has been maintained.

PURPOSE The aim of this study was to establish an in vitro model of nifedipine-induced gingival overgrowth and characterize the anti-fibrotic effect of hepatocyte growth factor (HGF) using this model. METHODS Human gingival fibroblasts were cultured-treated with 0.1, 1, or 10 µg/mL nifedipine or 10 ng/mL IL-1β + 0.1, 1, or 10 µg/mL nifedipine (0.1N, 1N, 10N, IL + 0.1N, IL + 1N, IL + 10N). Cell proliferation and levels of type I collagen, TGF-β1, CCN2/CTGF, and α-SMA were measured 48 h after the simultaneous addition of 10 and 50 ng/mL HGF (10 and 50HGF) along with IL-1β and nifedipine. Type I collagen was measured after administration of anti-HGF neutralizing antibody. RESULTS Significant increases in type I collagen, TGF-β1, and CCN2/CTGF were observed after treatment in the 1N and IL + 0.1N groups. Levels of type I collagen and CCN2/CTGF differed significantly between the IL + 0.1N group and the IL + 0.1N + 50HGF group. Production of type I collagen increased significantly following addition of anti-HGF antibody. CONCLUSION This study demonstrated the establishment of an in vitro model of nifedipine-induced gingival overgrowth by showing increased collagen levels. Experiments using this model suggested that HGF exerts anti-fibrotic effects.

BACKGROUND AND OBJECTIVE:Macrophages play important roles from the initiation of inflammation to wound healing. Two phenotypes of macrophages, namely pro-inflammatory type macrophages (M1-MΦ) and anti-inflammatory type macrophages (M2-MΦ), have been reported. Two contrasting metabolic enzymes that use arginine as a substrate, inducible nitric oxide synthase (iNOS), and arginase-1 (Arg-1), have been identified as M1-MΦ and M2-MΦ markers, respectively. The purpose of this study was to elucidate the temporal dynamics of the macrophage phenotype during the progression and healing phases of experimental periodontitis in mice.MATERIAL AND METHODS:A total of 63 C57BL/6J mice were divided into the following 3 groups: control (C), periodontitis (P), and healing (H). To induce periodontitis, a silk ligature was placed around the maxillary bilateral second molars of mice in the periodontitis and healing groups. In the healing group, the ligature was removed 3 days after ligation to induce tissue healing. Maxillary tissue was collected on day 0 for the control group, days 1, 3, 5, and 7 for the periodontitis group (P1, P3, P5, and P7), and days 5 and 7 for the healing group (H5 and H7: 3 days with the ligation + 2 days or 4 days following ligature removal). The left side of the maxilla was subjected to bone structure analysis using micro-computed tomography and gene expression analysis using polymerase chain reaction. On the right side, immunohistochemistry was performed to histopathologically evaluate the localization of macrophages by phenotype in the periodontal tissue.RESULTS:In the alveolar bone structure analysis, the linear distance of bone height increased significantly in the P5 and P7 groups, whereas bone volume fraction and bone mineral density decreased over time after ligature placement; in the healing group (H5 and H7), these parameters improved significantly compared with the periodontitis group (P5 and P7). Expression of genes encoding pro-inflammatory cytokines and iNOS increased in the periodontitis group, and expression of anti-inflammatory cytokine genes and Arg-1 increased in the healing group. Furthermore, the iNOS/Arg-1 expression ratio increased with ligation, whereas the ratio in the healing groups (H5 and H7) significantly decreased compared with the periodontitis groups (P5 and P7). Immunofluorescence staining revealed a significant increase in the number of iNOS-positive macrophages in the periodontitis group and decrease in the healing group. In contrast, the number of Arg-1-positive macrophages decreased in the periodontitis group and increased in the healing group.CONCLUSION:The results of the present study suggest that wound healing in periodontal disease induces macrophage polarization from M1-MΦ to M2-MΦ characterized by iNOS and Arg-1.