Porphyromonas Gingivalis-induced Periodontitis Research Articles

RgpA-Engineered/Functionalized DNA Vaccine as a Novel Prophylactic Vaccination to Prevent Porphyromonas gingivalis-Induced Periodontitis: An in Vivo Study.

Arg-gingipain A (rgpA) and Arg-gingipain B (rgpB) are crucial virulence factors associated with Porphyromonas gingivalis (P. gingivalis) and have been recognized as promising targets for antibacterial vaccines. Although vaccines containing rgpA have shown efficacy, the incorporation of rgpB, which lacks the haemagglutinin adhesin (HA) domain, diminishes the vaccine's effectiveness. This study aims to assess the immunogenicity of the functional HA domain of rgpA in mouse periodontitis models. A total of 24 mice were randomly divided into four groups, each receiving different immune injections: group A received phosphate-buffered saline (PBS) as an empty control; group B received pVAX1 as a negative control (NC); group C received pVAX1-HA; and group D received pVAX1-rgpA. The mice were subjected to intramuscular injections every two weeks for a total of three administrations. Prior to each immunization, blood samples were collected for antibody detection under isoflurane anesthesia. Following the final immunization, periodontitis was induced two weeks later by using sutures soaked in a P. gingivalis solution. The mice were euthanized after an additional two-week period. To assess the safety of the procedure, major organs were examined through hematoxylin-eosin (HE) staining. Subsequently, the levels of IgG, IgG1, and IgG2a in the serum were quantified via enzyme-linked immunosorbent assay (ELISA). Additionally, the expression of inflammatory factors in the gingiva, including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor alpha (TNF-α), was determined using quantitative real-time reverse transcript PCR (qRT-PCR). The extent of bone loss in periodontal tissues was evaluated using micro-computed tomography (micro-CT) and HE staining. HE staining of the organs confirmed the absence of vaccine-induced toxicity in vivo. After the second immunization, both the rgpA and HA groups displayed significantly higher specific IgG titers in comparison to the NC and PBS groups (p < 0.05). Furthermore, the rgpA and HA groups exhibited a noteworthy predominance of IgG1 antibodies after three immunization doses, while there was a noticeable reduction in IgG2a levels observed following ligation with P. gingivalis sutures, as opposed to the NC and PBS groups (p < 0.05). Additionally, both the HA and rgpA groups showed a significant decrease in the expression of inflammatory factors such as IL-6, IL-1β, and TNF-α, as well as a reduction in bone loss around periodontitis-affected teeth, when compared to the NC and PBS groups (p < 0.05). The results of this study demonstrate that the rgpA-engineered/functionalized HA gene vaccine is capable of eliciting a potent prophylactic immune response against P. gingivalis-induced periodontitis, effectively serving as an immunogenic and protective agent in vivo.

Porphyromonas gingivalis-induced periodontitis could contribute to cognitive impairment in Sprague-Dawley rats via the P38 MAPK signaling pathway.

Periodontitis is one of the most common oral diseases and has been shown to be a risk factor for systemic diseases. Our aim was to investigate the relationship between periodontitis and cognitive impairment and to explore the role of the P38 MAPK signaling pathway in this process. We established a periodontitis model by ligating the first molars of SD rats with silk thread and injecting Porphyromonas gingivalis (P. gingivalis) or P. gingivalis plus the P38 MAPK inhibitor SB203580 at the same time for ten weeks. We assessed alveolar bone resorption and spatial learning and memory using microcomputed tomography and the Morris water maze test, respectively. We used transcriptome sequencing to explore the genetic differences between the groups. The gingival tissue, peripheral blood and hippocampal tissue were assessed for the cytokines TNF-α, IL-1β, IL-6, IL-8 and C reactive protein (CRP) with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). We observed the presence of P. gingivalis in the hippocampus of rats by paraffin-fluorescence in situ hybridization (FISH). We determined the activation of microglia by immunofluorescence. Finally, Western blot analysis was employed to determine the expression of amyloid precursor protein (APP), β-site APP-cleaving enzyme 1 (BACE1) and P38MAPK pathway activation. We demonstrated that silk ligature-induced periodontitis plus injection of P. gingivalis into subgingival tissue could lead to memory and cognitive impairment. Transcriptome sequencing results suggested that there were neurodegenerative diseases in the P. gingivalis group, and the MWM test showed that periodontitis reduced the spatial learning and memory ability of mild cognitive impairment (MCI) model rats. We found high levels of inflammatory factors (TNF-α, IL-1β, IL-6, and IL-8) and CRP in the gingiva, peripheral blood and hippocampus, and the expression of APP and BACE1 was upregulated, as was the P38 MAPK pathway activation. Activated microglia and the presence of P. gingivalis were also found in the hippocampus. P38 MAPK inhibitors mitigated all of these changes. Our findings strongly suggest that topical application of P. gingivalis increases the inflammatory burden in the peripheral and central nervous systems (CNS) and that neuroinflammation induced by activation of P38 MAPK leads to impaired learning and memory in SD rats. It can also modulate APP processing. Therefore, P38 MAPK may serve as a linking pathway between periodontitis and cognitive impairment.

Anti-Inflammatory Effects of Geniposidic Acid on Porphyromonas gingivalis-Induced Periodontitis in Mice.

Periodontal disease is predominantly caused by the pathogenic bacterium Porphyromonas gingivalis that produces inflammation-inducing factors in the host. Eucommia ulmoides is a plant native to China that has been reported to reduce blood pressure, promote weight loss, and exhibit anti-inflammatory effects. Geniposidic acid (GPA) is the major component of E. ulmoides. Herein, we investigated the effects of GPA on P. gingivalis-induced periodontitis by measuring the inflammatory responses in human gingival epithelial cells (HGECs) after P. gingivalis stimulation and GPA addition in a P. gingivalis-induced periodontitis mouse model. We found that GPA addition suppressed interleukin (IL)-6 mRNA induction (33.8% suppression), IL-6 production (69.2% suppression), toll-like receptor (TLR) 2 induction, and mitogen-activated protein kinase (MAPK) phosphorylation in HGECs stimulated by P. gingivalis. Inoculation of mice with GPA inhibited P. gingivalis-induced alveolar bone resorption (25.6% suppression) by suppressing IL-6 and TLR2 production in the serum and gingiva. GPA suppressed osteoclast differentiation of bone marrow cells induced by M-CSF and sRANKL in mice (56.7% suppression). GPA also suppressed the mRNA expression of OSCAR, NFATc1, c-Fos, cathepsin K, and DC-STAMP. In summary, GPA exerts an anti-inflammatory effect on periodontal tissue and may be effective in preventing periodontal disease.

Nano-emulsion of mangosteen rind extract in a mucoadhesive patch for periodontitis regenerative treatment: An in vivo study

ObjectiveTo investigate the therapeutic potential of nano-emulsion of mangosteen rind extract in a mucoadhesive gingival patch on periodontitis, and its effect on tumor necrosis factor alpha (TNF-α), receptor activator of nuclear factor kappa Β ligand (RANKL), and interleukin 10 (IL-10) expression. MethodsSixty Wistar rats were divided into four groups: positive control group (mucoadhesive patch with doxycycline), negative control group (mucoadhesive patch), treatment group I (mucoadhesive patch with mangosteen rind extract), and treatment group II (mucoadhesive patch with nano-emulsion of mangosteen rind extract). An experimental model of Porphyromonas gingivalis-induced periodontitis was established in rats by treatment with 0.03 mL bacteria locally (1 × 1010 colony-forming units) seven times at 2-day intervals in the gingival sulcus of mandibular anterior teeth. Treatment was 1 h/day for 3 days. On days 3, 5, and 7, five rats from each group were killed. TNF-α, IL-10, and RANKL expression was determined by dissecting the lower jaw for immunohistochemistry. ResultsThe mucoadhesive patch with nano-emulsion mangosteen rind extract significantly decreased TNF-α and RANKL expression and increased IL-10 expression (p < 0.05) compared to the treatment I, positive and negative control groups. ConclusionA mucoadhesive gingival patch with nano-emulsion of mangosteen rind extract has the potential to treat periodontitis by decreasing TNF-α, RANKL, and increasing IL-10 expression.

The Effects of Rice Husk Liquid Smoke in Porphyromonas gingivalis-Induced Periodontitis.

Objectives The purpose of this study was to analyze the effects of rice husk liquid smoke in Porphyromonas gingivalis -induced periodontitis in the inflammatory and proliferation marker such as nuclear factor kappa β (NF-kB), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), transforming growth factor-β (TGF-β), fibroblast growth factor 2 (FGF2), collagen type 1 (COL-1) expression, and the number of macrophages, lymphocytes, and fibroblasts. Materials and Methods Rice husk liquid smoke is obtained by the pyrolysis process. Porphyromonas gingivalis -induced periodontitis in 20 μL phosphate-buffered saline containing 1 × 10 9 CFU was injected into the lower anterior gingival sulcus of Wistar rats. The periodontitis was then treated with 20 μL/20 g body weight of rice husk liquid smoke once a day for 2 and 7 days, respectively. After treatment, the bone and lower anterior gingival sulcus were analyzed with immunohistochemistry and hematoxylin–eosin staining. Results The treatment of periodontitis with rice husk liquid smoke showed a lower NF-kB, TNF-α, and IL-6 expression and a higher TGF-β, FGF2, and COL-1 expression than the control after treatment for 2 and 7 days ( p < 0.05), respectively. The number of macrophages and fibroblasts was also higher when compared with the control group ( p < 0.05), but the number of lymphocytes was lower than the control ( p < 0.05). Conclusion Rice husk liquid smoke showed its effects on Porphyromonas gingivalis -induced periodontitis with a decrease in inflammatory markers and an increase in proliferation markers. The development of a rice husk liquid smoke periodontitis treatment is promising.

Effects of omega-3 fatty acids and aspirin on Porphyromonas gingivalis-induced periodontitis in rats.

Periodontitis is a common chronic inflammatory disease caused by bacteria which can result in periodontal tissue inflammation, as well as alveolar bone resorption. The purpose of this study was to evaluate the effects of omega-3 fatty acids plus aspirin (ASA) on ligature-induced periodontitis in rats. Ninety-six male Sprague-Dawley (SD) rats (age 6 weeks) were randomly divided into eight groups (n=12 each) and had ligatures placed for 7days, followed by daily treatment with specific drug regimens for 14days. The rats were sacrificed 20days after drug treatment, and their maxillary were subjected to histomorphometric analysis. RAW264.7 cells were cultured with lipopolysaccharide (LPS) or receptor activator (NF)-κB ligand (RANKL), and treated with various concentrations of omega-3 and ASA. Then, cyclooxygenase (COX-2), inducible nitric oxide synthase (iNOS) protein expression and receptor activator of nuclear factor κ B (RANK), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-9 (MMP-9), MMP-2, and Cathepsin-K gene expression were detected. The administration of omega-3 fatty acids and aspirin significantly inhibited tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum of rats. Histomorphometric analysis showed omega-3 fatty acids plus aspirin promoted alveolar bone increase. Omega-3 fatty acids only, aspirin only, or omega-3 fatty acids plus aspirin also inhibited the protein expressions of COX-2 and iNOS in LPS-stimulated RAW264.7 cells. In addition, omega-3 combined with ASA also inhibited the RANKL-induced gene expressions of MMPs in dose-dependent manners. These results demonstrate that omega-3 fatty acids plus aspirin could decrease alveolar bone loss, while simultaneously increasing the protection against periodontal inflammation.

The therapeutic potential of regulatory T lymphocytes in periodontitis: A systematic review

This systematic review aimed to: (a) generate a descriptive synthesis of preclinical studies assessing the therapeutic potential of regulatory T lymphocytes (Tregs) to arrest periodontitis, (b) evaluate the methodological heterogeneity of the reviewed animal studies and (c) assess the risk of bias (RoB) of the included studies. The electronic search for animal studies included the MEDLINE, EMBASE, Web of Science and LILACS databases. In addition, a manual search assessed the high-ranked scientific journals in "periodontics/immunology" and the references listed in the included studies. There were no language, year or publication status restrictions. Two independent reviewers selected and extracted the data, and Cohen's Kappa coefficient was calculated to determine the inter-examiner agreement. The Systematic Review Center for Laboratory Animal Experimentation's (SYRCLE) tool was used to assess the RoB. A total of 21 of the 425 studies obtained from the database search were included. Treg function was mainly described in Porphyromonas gingivalis-induced periodontitis (57.1%) in mice (76.2%), where Treg suppression was strongly related to disease progression and Treg induction was strongly related to immuno-inflammatory response reduction. Of those 21 studies, eight included eight animal experiments using three distinct therapeutic approaches, including: P.gingivalis-driven immunization (n=3), retinoic acid inoculation (n=2) and anti-inflammatory molecules in polymeric carriers (n=3), which could modulate the Treg activity through cytokine production (interleukin-10 and transforming growth factor-β1), CC-chemokine- and CC-chemokine receptor-mediated chemoattraction (CCL22 and CCR4) or Th17-associated receptor activator of nuclear factor κB ligand (RANKL) downregulation. However, the studies with animal experiments did not specify the randomization sequences and housing conditions that were used, and therefore, 42.11% of the entries were rated as unclear RoB. Distinct therapeutic strategies involving Tregs could potentially suppress the immuno-inflammatory response and restore alveolar bone homeostasis during periodontitis. Nevertheless, important methodological variability, poor reporting of treatment effect estimates and unclear RoB suggest using caution when assessing the results of these studies.

Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1\u03b2 and TNF-\u03b1 production

BackgroundP-113 (AKRHHGYKRKFH-NH2) is a 12-amino-acid histidine-rich peptide derived from histatin 5 that is highly degradable in high salt concentrations and biological fluids such as serum, plasma and saliva. Nal-P-113, a novel antimicrobial peptide whose histidine residues are replaced by the bulky amino acids β-naphthylalanine, causes the antimicrobial peptide to retain its bactericidal activity even in physiological environments. This study evaluated the effect of the novel antimicrobial peptide Nal-P-113 in a rat periodontitis model and the mechanisms of action of Nal-P-113 for suppressing periodontitis.MethodsPeriodontitis was induced in mandibular first molars in rats receiving a ligature and infected with Porphyromonas gingivalis. Animals were randomly divided into six groups: a, P. gingivalis W83 alone; b, P. gingivalis W83 with 6.25 μg/mL of Nal-P-113; c, P. gingivalis W83 with 25 μg/mL of Nal-P-113; d, P. gingivalis W83 with 100 μg/mL of Nal-P-113; e, P. gingivalis W83 with 400 μg/mL of Nal-P-113; and f, control without P. gingivalis W83 or Nal-P-113. Morphometric analysis was used to evaluate alveolar bone loss. Microbiological assessment of the presence of Porphyromonas gingivalis and total bacteria was performed using absolute quantitative real-time PCR and scanning electron microscopy. Gingival tissue was collected for western blot and immunohistochemical assays of IL-1β and TNF-α levels.ResultsAlveolar bone loss was inhibited by 100 μg/mL or 400 μg/mL of Nal-P-113 compared to the control group (P < 0.05). Lower amounts of P. gingivalis and total bacteria were found in groups d and e compared with group a (P < 0.05). A decrease in the levels of IL-1β and TNF-α was detected in group d and group e compared to the control group (P < 0.05). The amount of P. gingivalis was positively correlated with IL-1β and TNF-α expression in periodontal tissue (P < 0.05).ConclusionsNal-P-113 exhibited protective effects on Porphyromonas gingivalis-induced periodontitis in rats by limiting the amount of bacteria and modulating IL-1β and TNF-α production. The use of Nal-P-113 in vivo might serve as a beneficial preventive or therapeutic approach for periodontitis.

The aggravation of arthritis by periodontitis is dependent of IL-17 receptor A activation.

To evaluate whether Porphyromonas gingivalis-induced periodontitis aggravates the antigen-induced arthritis (AIA) model, and whether this effect is dependent on the Th17/IL-17 signalling pathway. Antigen-induced arthritis was triggered by local injection of methylated bovine serum albumin into the knee joint of previously immunized C57BL/6 wild-type (WT) and IL-17 receptor A (IL-17RA)-knockout mice. Periodontal disease in naïve or arthritic mice was induced by oral infection with P. gingivalis. Animals were sacrificed 7, 15 and 30days after infection. Alveolar bone loss, joint histopathology, articular hyperalgesia and joint cytokine production were assessed, in addition to the proportion of Th17 and Treg cells isolated from the inguinal lymph nodes. No influence of experimentally-induced arthritis was found on the alveolar bone resorption induced by P. gingivalis. However, mice with experimentally-induced arthritis that were exposed to P. gingivalis presented higher joint damage and Th17 frequencies when compared to non-infected mice. The aggravation of arthritis by periodontitis was accompanied by increased TNF and IL-17 production and articular neutrophil infiltration, whereas arthritis aggravation and changes in neutrophil infiltration were absent in IL-17RA-deficient mice. The effects of P. gingivalis-induced periodontitis on arthritis are dependent on Th17 expansion and IL-17RA signalling, which lead to increased neutrophil infiltration into the joints.

Alveolar bone loss in relation to toll-like receptor 4 and 9 genotypes and Porphyromonas gingivalis carriage.

Toll-like receptors (TLRs) are highly developed sensors to detect microbe-associated molecular patterns. Functional polymorphisms of the genes TLR4 and TLR9 were found to be associated with alveolar bone loss in a Porphyromonas gingivalis-induced periodontitis model in mice. Our aim was to examine whether such an association can be detected in a group of Finnish adults. Polymorphisms of TLR4 Asp299Gly (rs4986790) and TLR9 rs187084 (1486 T/C) were genotyped by pyrosequencing and PCR from the saliva samples of 223 adults (age range 40-60years). Alveolar bone loss, measured from panoramic radiographs, were compared between TLR genotype groups according to subjects' salivary carriage of P. gingivalis, measured using a single copy gene-based real-time PCR. The frequencies of TLR4 wild type and heterozygote variants were 87.4% and 12.6%, respectively, while those of TLR9 wild type, heterozygote, and homozygote variants were 25.6%, 39.1%, and 35.3%, respectively. In the TLR4 heterozygote group, P. gingivalis-positive subjects had more alveolar bone loss than P. gingivalis-negative subjects (p = 0.027), while no difference was observed in the wild type group. P. gingivalis-negative individuals with TLR9 heterozygotes exhibited significantly less alveolar bone loss compared to those with TLR9 wild type (p = 0.007). Polymorphisms of TLR4 in P. gingivalis carriers seem to expose to alveolar bone loss. Polymorphisms of TLR9 can be protective against alveolar bone loss in the absence of P. gingivalis.

Periodontitis and arthritis interaction in mice involves a shared hyper-inflammatory genotype and functional immunological interferences

Periodontitis (PD) and rheumatoid arthritis (RA) have been found to be clinically associated and to share the chronic nature of the inflammatory reaction associated with bone resorption activity. However, the mechanisms underlying such association are unknown. Therefore, we examined the basis of Actinobacillus actinomycetemcomitans- and Porphyromonas gingivalis-induced PD and pristane-induced arthritis (PIA) interaction in mice. Higher severity PD in the genetically inflammation prone acute inflammatory reactivity maximum (AIRmax) mice strain was associated with higher levels of TNF-alpha, IL-1beta, IL-17, matrix metalloproteinase (MMP)-13, and RANKL, whereas PD/PIA co-induction resulted in even higher levels of IL-1beta, IFN-gamma, IL-17, RANKL, and MMP-13 levels. Conversely, PD/PIA co-induction in AIRmin strain did not alter the course of both pathologies. PIA/PD co-induction resulted in altered expression of T-cell subsets transcription factors expression, with T-bet and RORgamma levels being upregulated, whereas GATA-3 levels were unaltered. Interestingly, PIA induction resulted in alveolar bone loss, such response being highly dependent on the presence of commensal oral bacteria. No differences were found in PIA severity parameters by PD co-induction. Our results show that the interaction between experimental PD and arthritis in mice involves a shared hyper-inflammatory genotype and functional interferences in innate and adaptive immune responses.

Extracorporeal Shock Wave Therapy Induces Alveolar Bone Regeneration

Periodontal inflammation with alveolar bone resorption is a hallmark of periodontitis. We hypothesized that extracorporeal shock wave therapy (ESWT) could promote the regeneration of alveolar bone following Porphyromonas gingivalis-induced periodontitis in rats. Rats were infected with P. gingivalis for 10 wks, which caused alveolar bone resorption. The rats were then treated with a single episode of 100, 300, or 1000 impulses of shock wave on both cheeks at energy levels 0.1 mJ/mm(2). Alveolar bone levels were determined at 0, 3, 6, and 12 wks following ESWT and compared with those in untreated controls. Infected rats treated with 300 and 1000 impulses demonstrated significantly improved alveolar bone levels at 3 wks compared with untreated controls, and the improved levels remained for at least 6 wks in most rats. The results demonstrated effective regeneration of alveolar bone by ESWT and suggested that ESWT should be evaluated as an adjunct in the regeneration of periodontal tissues following periodontal disease. ESWT, extracorporeal shock wave therapy; PCR, polymerase chain-reaction.

1‐Tetradecanol Complex Reduces Progression of Porphyromonas gingivalis–Induced Experimental Periodontitis in Rabbits

It has been recently shown that monounsaturated fatty acids inhibit endothelial activation and reduce tissue responsiveness to cytokines. The present study has been planned to investigate topical application of a novel monounsaturated fatty acid complex (1-tetradecanol complex) for prevention of Porphyromonas gingivalis-induced periodontitis in rabbits. Experimental periodontitis was induced in New Zealand white rabbits with silk sutures tied around the mandibular second premolars bilaterally, followed by the topical application of 10(9) colony forming units (CFU) of P. gingivalis. 1-Tetradecanol complex (1-TDC) was topically applied at 1- and 10-mg/ml concentrations in five animals in each group, whereas control animals received olive oil vehicle (five animals) three times per week for 6 weeks. Negative controls included ligature alone (14 animals) or ligature + P. gingivalis (non-treatment; 15 animals). Rabbits were sacrificed after 6 weeks, and mandibular block sections were obtained; tissues were decalcified and embedded in paraffin. Thin sections (5 microm) were stained with hematoxylin and eosin or tartrate-resistant acid phosphatase. Macroscopic and histologic evaluation of samples was followed by the characterization of cellular inflammatory infiltrate and quantitative histomorphometric measurements. Treatment with both concentrations of 1-TDC and vehicle resulted in significant prevention of macroscopic periodontal inflammation and bone loss (75%; P <0.05) compared to the non-treatment (ligature + P. gingivalis) group, where significant periodontal tissue destruction characterized by attachment and bone loss was detected. However, there was no statistically significant difference between the vehicle and both 1-TDC groups. Histologically, 1-TDC inhibited inflammatory cell infiltration and prevented osteoclastogenesis, whereas treatment with vehicle did not show the same effect as in the 1-TDC groups; the difference between vehicle and the higher concentration of 1-TDC (10 mg/ml) was statistically significant. Topical application of an esterified monounsaturated fatty acid complex (1-TDC) was found promising in preventing bone loss, inflammatory cell infiltration, and connective tissue destruction in the rabbit periodontitis model.

Inhibitory effects of incadronate on the progression of rat experimental periodontitis by porphyromonas gingivalis infection.

Incadronate (YM175, disodium cycloheptylaminomethylenediphosphonate monohydrate), a bisphosphonate, has been suggested to prevent the bone resorption associated with periodontitis by inhibiting osteoclast activity. The purpose of this study was to investigate the effect of incadronate in preventing periodontal destruction in rats with Porphyromonas gingivalis-induced periodontitis. Periodontitis was induced in 35 Wister rats by inoculating P. gingivalis into the oral cavity and feeding the rats a soft diet for 4 weeks. Incadronate or placebo was administered to the oral cavity of the rats 2 days per week for 2, 4, or 8 weeks. P. gingivalis infection resulted in destruction of the periodontal ligament, reduced bone density, and caused inflammatory cell migration. Radiographic, morphometric, and histological results showed that incadronate had the ability to increase the bone mineral density (quantum level score; cortex 518.9 [placebo 612.8]; sponge 579.8 [placebo 672.0]) and to prevent periodontal ligament destruction (width 0.16 mm [placebo 0.20 mm]; area 0.36 mm2 [placebo 0.54 mm2]) after 8 weeks' administration. Furthermore, the polymorphonuclear leukocyte (PMN) infiltration in gingival tissue was significantly decreased. These results showed that incadronate inhibits bone resorption and PMN migration in P. gingivalis-induced periodontitis.