Perlecan-enriched intercellular space of junctional epithelium provides primary infrastructure for leukocyte migration through squamous epithelial cells.

The aim of this study was to demonstrate the presence of intraepithelial stroma represented by extracellular matrix (ECM) deposits in the junctional epithelium to clarify its function as a scaffold for leukocyte migration through epithelial cells. Twenty-three biopsy specimens from the gingiva including the junctional epithelium were examined to determine comparative protein and gene level expression profiles for keratin and ECM molecules between the junctional epithelium and the gingival epithelium using immunohistochemistry and in situ hybridization. Intraepithelial leukocyte types and frequencies were also determined and compared between the junctional and gingival epithelia. In the junctional epithelium, which was positive for keratin 19, perlecan was strongly deposited in intercellular space of the whole epithelial layer, while it was faintly positive around the parabasal layer of the gingival epithelium. Perlecan mRNA signals were enhanced to a greater degree in both epithelial and inflammatory cells within the junctional epithelium. In the junctional epithelium, greater numbers of neutrophils and macrophages were found as compared with the gingival epithelium. Our results showed that perlecan is the primary ECM molecule comprising intraepithelial stroma of the junctional epithelium, in which leukocytes may migrate on ECM scaffolds in intercellular space toward the surface of the gingival sulci or pockets.

Efficacy of Erbium:YAG Laser for Regenerative Surgical Treatment of Peri-implantitis: Clinical, Microbiological, and Biomarker Analyses.

This paper reports on a study undertaken to ascertain the efficacy of the erbium:YAG laser (EYL) for peri-implantitis treatment. A total of 12 patients with bone loss resulting from peri-implantitis were involved in this study. The treatment protocol consisted of using the EYL for implant surface debridement and deproteinized bovine bone mineral (DBBM) for bone grafting. The following parameters were analyzed: probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), bone levels (BLs), and the lipopolysaccharide levels before and after debridement with the EYL. This study found a statistically significant improvement in PPD, CAL, BOP, and BL at 3 and 12 months postoperative. Furthermore, a statistically significant decrease in implant-surface LPS levels was observed following debridement with the EYL. These findings show that using the EYL for debridement in peri-implantitis cases is effective in decreasing LPS levels. Moreover, after partial reconstruction with DBBM grafting, BLs were restored for at least 12 months. It was shown in one case that BLs had remained stable over 6 years, which also attests to the efficacy of this treatment. The combined use of EYL and DBBM could be effective for regenerative surgical peri-implantitis treatment.

Altered gene expression levels of matrix metalloproteinases and their inhibitors in periodontitis-affected gingival tissue.

BACKGROUND: The balance between the degradation and synthesis of extracellular matrix determines periodontal attachment levels and alveolar bone matrix concentration in periodontal diseases. Matrix metalloproteinases (MMPs) are known to degrade periodontal ligamental attachment and bone matrix proteins. The purpose of this study was to examine the effect of different expression levels of MMPs and their inhibitors, the tissue inhibitors of matrix metalloproteinases (TIMPs), in periodontitis. METHODS: Sixteen inflamed gingival tissue samples from subjects with generalized chronic periodontitis and 14 control tissue samples from systemically and periodontally healthy subjects were evaluated. The total RNA was extracted, and the transcript levels for MMP-1, -3, -9, and -13 and TIMP-1, -2, -3, and -4 relative to beta-actin were determined by quantitative real-time reverse transcription-polymerase chain reaction. RESULTS: Gene transcript levels for MMP-1 and TIMP-4 were significantly higher in periodontitis-affected gingival tissues (P <0.05). MMP-3, -9, and -13 and TIMP-1 mRNAs also were elevated in periodontitis; however, the difference was not statistically significant. TIMP-2 and -3 mRNA levels were similar in healthy and diseased gingivae. The ratios of MMP-1/TIMP-2 (P <0.01), MMP-3/TIMP-2 (P <0.05), MMP-9/TIMP-2 (P <0.05), and MMP-1/TIMP-3 (P <0.01) from periodontitis lesions were significantly higher than those in the control tissues. CONCLUSIONS: Upregulated MMP expression and an increased MMP/TIMP ratio indicate that a potential imbalance between degradation and synthesis of extracellular matrix persists in periodontitis-affected gingival tissues. This process may be responsible for increased tissue breakdown in periodontitis.

Clinical and CBCT Evaluation of Combined Periodontal Regenerative Therapies Using Enamel Matrix Derivative and Deproteinized Bovine Bone Mineral With or Without Collagen Membrane.

Use of collagen membrane (CM) with deproteinized bovine bone mineral (DBBM) and enamel matrix derivative (EMD) in periodontal regenerative therapy was evaluated. A total of 40 intrabony defects in periodontitis patients were treated. Clinical parameters and filled bone volume (FBV) and rate (FBR) were assessed. Probing pocket depth (PPD) was reduced significantly at 12 months with CM treatment, while clinical attachment level (CAL), FBV, and FBR showed similar improvements. In stratified analyses, CM-treated thick-biotype patients showed significant improvement in PPD and CAL. Regenerative therapy with the use of EMD and DBBM showed similar improvements in periodontal tissue regeneration with or without CM. The combination with CM appeared to influence the healing of soft tissue and was effective in decreasing pocket depth.

Effectiveness of an erbium-doped: yttrium, aluminum and garnet laser for treatment of peri-implant disease: Clinical, microbiological, and biochemical marker analyses.

BACKGROUND: The effectiveness of an erbium-doped: yttrium, aluminum and garnet (Er: YAG) laser (EYL) for the treatment of peri-implant disease (PID) remains unclear. The aim of this study was to compare non-surgical EYL therapy for PID with locally delivered minocycline hydrochloride (MC) ointment therapy by evaluating clinical, microbiological, and biochemical markers. MATERIAL AND METHODS: Thirty-seven patients with PID were randomly assigned to either the EYL group (n = 18) or the MC group (n = 19). The clinical, microbiological, and biochemical markers at baseline and at 1 and 3 months after treatment were compared between the two groups. Subgingival plaque and peri-implant crevicular fluid (PICF) were collected from the diseased pockets. RESULTS: In the EYL group, probing pocket depth (PPD) was significantly decreased after treatment when compared with baseline. On the other hand, in the MC group, there was no significant decrease in PPD after treatment. Specific bacteria associated with PID were not determined. The counts of both Gram-positive and -negative species did not significantly decrease in the EYL group at 3 months after treatment. In the MC group, the counts of almost all bacterial species were significantly decreased after treatment. Biochemical marker analysis of PICF revealed significantly lower levels of metalloproteinase (MMP)-9 in the EYL group, as compared with the MC group at 3 months after treatment (p= 0.009). CONCLUSIONS: Non-surgical therapy with an EYL for PID was clinically effective, with decreased MMP-9 levels in PICF, which may lead to reduced peri-implant tissue destruction. Key words:Er: YAG laser; peri-implant disease; biomarker; peri-implant crevicular fluid.

Effects of Antimicrobial Photodynamic Therapy and Local Administration of Minocycline on Clinical, Microbiological, and Inflammatory Markers of Periodontal Pockets: A Pilot Study.

OBJECTIVE: We evaluated the efficacies of antimicrobial photodynamic therapy (aPDT) and minocycline ointment (MO) on clinical and bacteriological markers and the local host inflammatory response. MATERIALS AND METHODS: A total of 30 patients with chronic periodontitis were randomly assigned to two groups. Selected periodontal pockets (probing depth 5-7 mm with bleeding on probing) were treated with aPDT or MO. Measurements of clinical parameters and the collection of gingival crevicular fluid (GCF) and subgingival plaque were performed at baseline, and at 1 and 4 weeks after treatment. Quantification of periodontopathic bacteria in the sulcus and a multiplex bead immunoassay of ten inflammatory cytokines in the GCF were performed. RESULTS: Local MO administration exhibited a significant decrease in scores for clinical parameters (P < 0.01) and a significant reduction in bacterial counts (P < 0.01) and interleukin-1ß and interferon-γ levels at 1 and 4 weeks after treatment (P < 0.01). No significant changes were observed in the aPDT group, except in clinical parameters. CONCLUSIONS: Although our study had some limitations, we found that while local administration of MO may slightly help to improve clinical, microbiological, and crevicular cytokine levels in periodontal pockets, aPDT did not show any effects. This trial is registered with the UMIN Clinical Trials Registry UMIN000013376.

The 2G allele of promoter region of matrix metalloproteinase-1 as an essential pre-condition for the early onset of oral squamous cell carcinoma.

BACKGROUND: Matrix metalloproteinase (MMP) is known to be involved in the initial and progressive stages of cancer development, and in the aggressive phenotypes of cancer. This study examines the association of single nucleotide polymorphisms in promoter regions of MMP-1 and MMP-3 with susceptibility to oral squamous cell carcinoma (OSCC). METHODS: We compared 170 Japanese OSCC cases and 164 healthy controls for genotypes of MMP-1 and MMP-3. RESULTS: The frequency of the MMP-1 2G allele was higher and that of the 1G homozygote was lower in the OSCC cases (p = 0.034). A multivariate logistic regression analysis revealed that subjects who were 45 years old or older had a significantly increased (2.47-fold) risk of OSCC (95%CI 1.47-4.14, p = 0.0006), and those carrying the MMP-1 2G allele had a 2.30-fold risk (95%CI 1.15-4.58, p = 0.018), indicating independent involvement of these factors in OSCC. One of the key discoveries of this research is the apparent reduction of the MMP-1 1G/1G and 1G/2G genotype distributions among the early onset OSCC cases under the ages of 45 years. It should be noted that the tongue was the primary site in 86.2% of these early onset cases. This could suggest the specific carcinogenic mechanisms, i.e. specific carcinogenic stimulations and/or genetic factors in the tongue. CONCLUSION: Since the 2G allele is a majority of the MMP-1 genotype in the general population, it seems to act as a genetic pre-condition in OSCC development. However this report suggests a crucial impact of the MMP-1 2G allele in the early onset OSCC.

Synergistic effects of the combined use of human-cultured periosteal sheets and platelet-rich fibrin on bone regeneration: An animal study.

A human-cultured alveolar bone-derived periosteal (hCP) sheet is an osteogenic grafting material used clinically in periodontal regenerative therapy, while platelet-rich fibrin (PRF), a platelet concentrate with fibrin clot, is considered to augment the wound healing process. Therefore, whether the combined use of hCP-PRF complex could facilitate bone regeneration synergistically was evaluated in animal models. Human periosteal segments (1 × 1 mm) were cultured initially on plastic dishes and formed an hCP sheet. The hCP sheet was implanted with freshly prepared human PRF into subcutaneous tissue (hCP: n = 4, hCP + PRF: n = 4) and 4 mm diameter calvarial bone defect models (hCP: n = 4, hCP + PRF: n = 4, control [defect-only]: n = 4) that prepared in nude mice. At 4 weeks postimplantation, new bone formation was evaluated by using µCT. Cell growth and neovascularization were evaluated by histochemical and immunohistological methods. In the subcutaneous tissue, mineral deposit formation, collagen deposition, and number of vessels were higher in the hCP + PRF group than in the hCP alone group. In the calvarial defect models, new bone formation was significantly higher in the hCP + PRF group than in the hCP alone group and defect-only control group. The numbers of vessels and PCNA-positive cells in calvarial defects were also increased in the hCP + PRF group more than in the hCP alone group. Platelet-rich fibrin preparations support the proliferation and the growth of periosteal cells to form well-combined active biological materials. Platelet-rich fibrin also stimulates the local angiogenesis in the implantation site. Therefore, the combined use of hCP and PRF could be clinically applicable in bone regeneration therapy.

Prevalence and risk factors for peri-implant diseases in Japanese adult dental patients.

We investigated the prevalences and risk factors for peri-implant diseases in Japanese adult dental patients attending a follow-up visit at dental hospitals or clinics as part of their maintenance program. This cross-sectional multicenter study enrolled patients with dental implants who attended regular check-ups as part of a periodontal maintenance program during the period from October 2012 through September 2013. Patients with implants with at least 3 years of loading time were included in the study. The condition of peri-implant tissue was examined and classified into the following categories: healthy, peri-implant mucositis, and peri-implantitis. Patients were also evaluated for implant risk factors. A total of 267 patients (110 men, 157 women; mean age: 62.5 ± 10.7 years) were analyzed. The prevalence of patient-based peri-implant mucositis was 33.3% (n = 89), and the prevalence of peri-implantitis was 9.7% (n = 26). Poor oral hygiene and a history of periodontitis were strong risk factors for peri-implant disease. The present prevalences were lower than those previously reported. The quality of periodontal therapy before and after implant installation and patient compliance and motivation, as indicated by plaque control level, appear to be important in maintaining peri-implant tissue health.

Microbiological effect of essential oils in combination with subgingival ultrasonic instrumentation and mouth rinsing in chronic periodontitis patients.

Thirty chronic periodontitis patients were randomly assigned to 3 groups: control, saline, and essential oil-containing antiseptic (EO). Subgingival plaque was collected from a total of 90 pockets across all subjects. Subsequently, subgingival ultrasonic instrumentation (SUI) was performed by using EO or saline as the irrigation agent. After continuous mouth rinsing at home with EO or saline for 7 days, subgingival plaques were sampled again. Periodontopathic bacteria were quantified using the modified Invader PLUS assay. The total bacterial count in shallow pockets (probing pocket depth (PPD) = 4-5 mm) was significantly reduced in both saline (P < 0.05) and EO groups (P < 0.01). The total bacterial count (P < 0.05) and Porphyromonas gingivalis (P < 0.01) and Tannerella forsythia (P < 0.05) count in deep pockets (PPD ≥6 mm) were significantly reduced only in the EO group. In comparisons of the change ratio relative to baseline value of total bacteria counts across categories, both the saline and EO groups for PPD 4-5 mm and the EO group for PPD 6 mm showed a significantly low ratio (P < 0.05). The adjunctive use of EO may be effective in reducing subgingival bacterial counts in both shallow and deep pockets. This trial is registered with UMIN Clinical Trials Registry UMIN000007484.

Gene and protein localisation of tumour necrosis factor (TNF)-α converting enzyme in gingival tissues from periodontitis patients with drug-induced gingival overgrowth.

OBJECTIVE: It is known that tumour necrosis factor (TNF)-α converting enzyme (TACE) plays a crucial role in fibrotic inflammatory diseases, and is specifically inhibited by tissue inhibitor of metalloproteinase (TIMP)-3. Fibrotic drug-induced gingival overgrowth (GO) is often combined with periodontitis. However, neither TACE nor TIMP-3 has been thoroughly examined in periodontal tissues to date. The aim of the present study was to analyse mRNA expression of TACE and TIMP-3, and protein localisation of TACE in gingival tissues removed from drug-(calcium-channel blocker) induced GO and periodontitis. METHODS: A total of 30 gingival tissue samples were taken from 15 GO and 15 periodontitis patients. The mRNA expression levels were analysed by quantitative reverse transcription polymerase chain-reaction (qRT-PCR) and the protein localisation was investigated by immunohistochemistry. Statistical analysis was performed using the Mann-Whitney U-test. RESULTS: TACE and TIMP-3 mRNA levels were significantly higher in GO compared to the periodontitis groups, as revealed by qRT-PCR (p<0.05). TACE-producing cells were immunohistochemically detected among monocytes/macrophages, plasma cells and some epithelial cells. TACE immunoreactivity was shown to be more intense in GO than in periodontitis-gingival tissue. CONCLUSIONS: We have demonstrated TACE expression in cells such as macrophages, plasma cells and epithelial cells, and its predominant expression in GO tissues. This data suggests that TACE expression in GO-gingiva could be involved in the pathogenesis of disease.

Microarray and quantitative RT-PCR analyses in calcium-channel blockers induced gingival overgrowth tissues of periodontitis patients.

OBJECTIVES: The purpose of the present study was to analyse transcriptomes and mRNA expression levels for specific genes in calcium-channel blocker-induced gingival overgrowth (GO) tissues. DESIGN: Eight gingival tissues samples (from both GO negative and positive sites) were harvested from four GO patients for microarray analyses. Twelve candidate genes were selected for further quantitative real time reverse transcription-polymerase chain reaction (qRT-PCR) analyses. Ten GO tissues from periodontitis patients and ten control gingival tissues from healthy subjects were compared by qRT-PCR. Mann-Whitney U-test was used for statistical evaluation. RESULTS: In GO positive tissues, 163-1631 up-regulated and 100-695 down-regulated genes were identified with more than two-fold changes compared with GO negative tissues amongst patients by microarray experiments. No commonly expressed genes amongst the eight sets of microarray data were found. The clustering analysis confirmed that the entire transcriptome patterns showed similarities in individuals, but differences amongst the four patients. The qRT-PCR and statistical analyses for the candidate genes, though, revealed differential gene expressions between GO-positive and negative tissues. We found that matrix metalloproteinase (MMP)-1 and MMP-12 as well as cathepsin-L were significantly up-regulated whilst keratin-10 and transforming growth factor-ß1 were significantly down-regulated in GO tissues of periodontitis patients compared with the control gingival tissues of healthy subjects. CONCLUSION: The microarray analyses revealed that GO pathogenesis was complex and individually varied, though GO-affected gingival tissues were controlled at least by genes related to collagen metabolisms including regulated MMPs, cathepsin-L, growth factors, and keratins to maintain tissue homeostasis in vivo.

Effects of irrigation with an antiseptic and oral administration of azithromycin on bacteremia caused by scaling and root planing.

BACKGROUND: Transient bacteremia frequently occur secondary to several periodontal procedures. The purpose of the present study is to investigate the effects of irrigation with an essential oil-containing antiseptic (EO) and oral administration of azithromycin (AZM) on bacteremia caused by scaling and root planing (SRP). METHODS: Thirty patients with chronic periodontitis were randomly assigned to three groups (control, EO, and AZM). The EO group received quadrant subgingival irrigation with EO, and mouthrinsing was continued at home for 1 week. Oral administration of AZM was started 3 days before SRP in the AZM group. No adjunctive treatment was performed before SRP in the control group. Peripheral blood and subgingival plaque were collected at baseline and after 1 week. The second blood sample was taken 6 minutes after the initiation of quadrant SRP. The blood samples were cultured and analyzed for bacteremia. Quantitative analysis of periodontopathic bacteria in the sulcus was performed using the polymerase chain reaction Invader method. RESULTS: Bacteremia incidence rates were 90%, 70%, and 20% for the control, EO, and AZM groups, respectively. Significant reduction of the incidence of bacteremia was shown in the AZM group only (P <0.01). Subgingival bacterial counts significantly decreased in both the EO and AZM groups (P <0.01). CONCLUSIONS: Quadrant SRP frequently induced bacteremia. Although AZM was effective in reducing bacteremia incidence, EO showed less effectiveness.

Differential gene and protein expression of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues from drug induced gingival overgrowth.

OBJECTIVES: The purpose of this study was to analyse mRNA expression and protein localization of tissue inhibitors of metalloproteinases (TIMP)-3 and TIMP-4 in gingival tissues removed from drug (calcium-channel blocker) induced gingival overgrowth and periodontitis patients. DESIGN: Employing RT-PCR, we evaluated TIMP-3 and TIMP-4 mRNA levels of 20 human gingival tissue samples taken from patients suffering gingival overgrowth (GO) and periodontitis (P). Then, using immunohistochemistry we investigated the TIMP-3 and TIMP-4 protein localization of five sample tissues from each group. RESULTS: TIMP-4 mRNA levels in GO-gingiva tended to be lower than in P-gingiva but the results differed little (p = 0.22). Varying degrees of inflammation in the protein localization of TIMP-3 and TIMP-4 were found. TIMP-4 immunoreactivity (IR) was weak in the endothelial cells, fibroblasts, epithelial basal and parabasal cells while the degree of inflammation differed as well. TIMP-3 and TIMP-4 IR in inflammatory cells, including lymphocytes, plasma cells, and macrophages, were faint and intense respectively. For P-gingiva, both TIMP-3 and TIMP-4 IR expression was weak in the endothelial cells, fibroblasts, basal and parabasal epithelial layers. Expression of TIMP-3 was faint in the inflammatory cells, whereas TIMP-4 IR was strong. CONCLUSION: Our findings suggest that TIMP-3 and TIMP-4 expression differs in GO and P-gingival tissues, both of which are potentially involved in pathogenesis.

Alterations of gene expression in human neutrophils induced by smoking cessation.

OBJECTIVE: The purpose of the present study was to investigate the effect of smoking cessation on the peripheral neutrophil mRNA expression levels for inflammatory cytokines, chemokine, growth factor and matrix metalloproteinase (MMP). MATERIAL AND METHODS: Sixteen male smokers (aged 22-39 [25.3+/-4.0] years), with no clinical signs of periodontal and systemic diseases, were recruited. The experiment was performed before (baseline) and at 1, 4 and 8 weeks after smoking cessation. The status of smoking and smoking cessation was verified by exhaled carbon monoxide (CO) concentration and serum cotinine concentration. Neutrophils were isolated from each subjects' peripheral blood, then the cell was stimulated with N-formyl-methionyl-leucyl-phenylalanine (FMLP). The mRNA expression levels for interleukin (IL)-1 beta, IL-8, tumor necrosis factor (TNF)-alpha, vascular endothelial growth factor (VEGF) and MMP-8 were analyzed by semiquantitative reverse transcription-polymerase chain reactions. The same experiment was performed on 11 non-smoking controls (four female and seven male), aged 23-27 (24.4+/-1.2) years. RESULTS: Eleven of 16 smokers successfully completed smoking cessation for 8 weeks. At 1 day after smoking cessation, there was a statistically significantly lower CO concentration than at baseline (p<0.01). Also, cotinine concentration markedly decreased at the second measurement, which was taken at 1 week. All of the analyzed mRNA expression levels of neutrophils from smokers were statistically significantly lower than that in non-smokers (p<0.01: IL-1 beta, IL-8, VEGF; p<0.05: TNF-alpha, MMP-8). The MMP-8 mRNA levels were statistically significantly increased at 8 weeks after smoking cessation compared with the baseline (p<0.05). Although the other mRNA expression levels were also elevated gradually from the baseline, they did not reach the statistically significant levels at 8 weeks after smoking cessation. CONCLUSION: The results showed that the neutrophil transcript levels in smokers were generally lower than those in non-smokers, which could be related to an impairment of neutrophils by smoking effects. The significant increase of MMP-8 mRNA levels were associated with the effects of smoking cessation, while recovery of the other mRNA levels seemed to require a bit longer period beyond 8 weeks after smoking cessation.

Smoking cessation increases gingival blood flow and gingival crevicular fluid.

OBJECTIVES: The purpose of the present study was to determine the effect of smoking cessation on gingival blood flow (GBF) and gingival crevicular fluid (GCF). MATERIAL AND METHODS: Sixteen male smokers (aged 22-39 (25.3+/-4.0) years), with no clinical signs of periodontal and systemic diseases, were recruited. The experiment was performed before (baseline) and at 1, 3 and 5 days, and at 1, 2, 4 and 8 weeks after smoking cessation. The status of smoking and smoking cessation was verified by exhaled carbon monoxide (CO) concentration, and by serum nicotine and cotinine concentrations. A laser Doppler flowmeter was used to record relative blood flow continuously, on three gingival sites of the left maxillary central incisor (mid-labial aspect of the gingival margin and bilateral interdental papillae). The GCF was collected at the mesio- and disto-labial aspects of the left maxillary central incisor and the volume was calculated by the Periotron 6000(R) system. The same measurements except for the GBF were performed on 11 non-smoking controls (four females and seven males), aged 23-27 (24.4+/-1.2) years. RESULTS: Eleven of 16 smokers successfully completed smoking cessation for 8 weeks. At 1 day after smoking cessation, there was a significantly lower CO concentration than at baseline (p<0.01). Also, nicotine and cotinine concentrations markedly decreased at the second measurement. The GBF rate of smokers was significantly higher at 3 days after smoking cessation compared to the baseline (p<0.01). While the GCF volume was significantly increased at 5 days after smoking cessation compared to the baseline (p<0.01), it was significantly lower than that of non-smokers until 2 weeks after smoking cessation (p<0.01). CONCLUSION: The results show that the gingival microcirculation recovers to normal in the early stages of smoking cessation, which could activate the gingival tissues metabolism/remodeling, and contribute to periodontal health.

Matrix metalloproteinase-1 and -3 gene promoter polymorphisms in Japanese patients with periodontitis.

BACKGROUND/AIMS: Matrix metalloproteinase (MMP)-1 and MMP-3 have important roles in the connective tissue remodelling and destruction processes in periodontitis. MMP-1 1G/2G (-1607) and MMP-3 5A/6A (-1171) polymorphisms have been identified and appear to influence the transcription of the genes. The aim of this study was to investigate whether these gene promoter polymorphisms were associated with the susceptibility to periodontitis. MATERIAL AND METHODS: Genomic DNA was obtained from 37 generalised aggressive, 205 slight-to-severe generalised chronic-periodontitis patients and 142 healthy subjects. All subjects were non-smoking Japanese. We genotyped by using TaqMan PCR assay. The statistics were analysed by chi2-test. RESULTS: We found no significant differences in genotype distributions, allele frequencies, carriage rates and haplotype frequencies in the MMP-1 and the MMP-3 gene promoter polymorphisms among all groups. The distributions of MMP-1 and MMP-3 genotypes in our study were different from those of previously reported in Caucasians or Brazilians, but consistent with previously reported in Japanese. CONCLUSION: Our data did not support the hypothesis that MMP-1 and/or MMP-3 gene promoter polymorphisms influenced the susceptibility to periodontitis in Japanese patients, indicating MMP-1 and MMP-3 expressions were regulated by complex processes such as cytokine network in periodontal disease rather than gene polymorphisms.