Anti-NGF treatment reduces bone resorption in periodontitis.

Periodontitis is characterized by periodontal tissue destruction, including the alveolar bone. One of its critical components is the release of pro-inflammatory neuropeptides from sensory nerve endings innervating the periodontium. Since nerve growth factor (NGF) has been reported to up-regulate neuropeptides in sensory neurons, we hypothesized that it would be increased in ligature-induced periodontitis in rats, and that systemic NGF neutralization would reduce the periodontitis-associated alveolar bone resorption. Real-time PCR analysis disclosed a statistically significant time-dependent up-regulation of NGF mRNA in gingiva during 2 weeks of periodontitis. Interestingly, NGF up-regulation was also detected in the contralateral gingiva. In addition, immunohistochemistry of trigeminal ganglion neurons innervating the gingivomucosa demonstrated increased expression of TrkA receptor for NGF. Systemic anti-NGF treatment during periodontitis significantly reduced interleukin-1beta expression in gingiva and bilateral alveolar bone resorption. This suggests that NGF promotes periodontal inflammation and implicates a possible use of anti-NGF treatment in periodontitis.

Chronic ingestion of Porphyromonas gingivalis induces systemic nitric oxide response in mice.

INTRODUCTION: Porphyromonas gingivalis induces nitric oxide (NO) production in various cells, systemic NO elevation being expected in chronic oral challenge. METHODS: Groups of BALB/c mice were inoculated orally with either live P. gingivalis ATCC 33277 or sterile broth on days 0, 2 and 4, with or without later administration of the inducible nitric oxide synthase (iNOS) inhibitor 1400W. Plasma and tissues were harvested on day 42 for assays of tumor necrosis factor-alpha (TNF-alpha), nitrite and nitrate (NOx) and tissue NO, or histology and iNOS immunohistochemistry. RESULTS: No signs of gingivitis were observed, but plasma NOx was significantly elevated (P = 0.028) as was TNF-alpha (P = 0.079) in P. gingivalis-inoculated animals compared with controls, NOx being reduced when 1400W was used. NO production in organs showed a similar trend, with significant elevation in liver (P = 0.017) and kidneys (P = 0.027), whereas concomitant treatment of inoculated animals with 1400W caused significant reductions in NO in aorta (P = 0.008) and kidneys (P = 0.046). Sham-inoculated 1400W-treated animals had significantly increased plasma NOx (P = 0.004) and liver NO (P = 0.04). NOx in plasma correlated significantly with NO production in lungs (0.35, P = 0.032) and kidneys (0.47, P = 0.003). Immunohistochemistry demonstrated iNOS activity in many tissues in all groups. CONCLUSION: Repeated oral administration of P. gingivalis induced systemic NO and NOx production in mice, probably by activating iNOS as suggested by the response to 1400W.

T1 relaxation time and magnetic resonance imaging of inflamed gingival tissue.

OBJECTIVES: The aim of this study was to evaluate the use of MRI as a non-invasive method for the characterization of the inflammation and healing processes in periodontal tissues. METHODS: For the in vitro study, 99 gingival samples were collected during periodontal surgical treatment and T1 relaxation time measurements were performed and correlated to the probing depth measurements recorded at the collection sites. For the in vivo study, a group of eight patients with moderate to advanced periodontal disease was examined with pre-contrast and Gd-DTPA contrast-enhanced T1 weighted MRI both before and 3 months after non-surgical periodontal therapy. On the MR images of the 8 patients, 53 regions of interest (ROIs) were selected. For each ROI, the ratio between post- and pre-contrast signal intensity (RSI) was calculated and used as a measure for the degree of inflammation. RESULTS: The in vitro T1 relaxation times measurements of gingival samples showed an increase in relaxation times with the increase of probing depth at the sites of tissue removal. The in vivo studies demonstrated that the reduction of inflammation and probing depth in gingival tissues after non-surgical periodontal therapy correlates with a decrease of RSI in T1 weighted MR images. The non-invasively obtained data provide the characteristic ratio U, which shows that two distinct types of inflammation occurred in the examined group of patients. CONCLUSIONS: The results of MRI provide a new possibility to characterize the type and healing process of periodontal inflammation.

Single gavage with Porphyromonas gingivalis reduces acute systemic nitric oxide response in mice.

INTRODUCTION: Porphyromonas gingivalis, an important periodontal pathogen, can also induce host responses in distant tissues. P. gingivalis induces nitric oxide (NO) production in immune system cells and non-immune system cells, therefore NO might be involved in an acute systemic host response. METHODS: Eighteen female BALB/c mice were perorally inoculated with 10(8) colony-forming units live P. gingivalis ATCC 33277. Plasma nitrite and nitrate (NOx) and NO production in lungs, aorta, heart, liver, spleen, kidneys, and brain were measured at intervals after inoculation and compared with levels in 11 control animals. RESULTS: NOx levels were significantly (P = 0.017) lower at 7, 13, and 25 h after P. gingivalis inoculation. A similar trend in NO production occurred in most tested organs, but never reached statistical significance. The correlation between NOx in plasma and NO in liver was positive (Spearman correlation coefficient = 0.81, P = 0.0025) and marginal for kidney (0.58, P = 0.059). CONCLUSION: Single peroral inoculation of mice with P. gingivalis reduces the acute systemic NO response. As NO is important for host defense, the reduction of NO levels after exposure is likely to delay the host response, increasing the chances that infection with P. gingivalis will become established.

Curriculum structure: principles and strategy.

This report provides general guidelines for the structure of a curriculum, followed by specific advice on the principles of learning and teaching, the process of restructuring and change leadership and management. It provides examples of several educational philosophies, including vertical and horizontal integration. It discusses the use of competence, learning outcomes, level of degree and assessment and provides a number of recommendations. It does not seek to be prescriptive of time allocation to disciplines within a curriculum. Although this report has been written primarily for those who will develop an undergraduate curriculum, the information may be sufficiently generic to apply to the recent development in graduate entry ('shortened dental' or 'accelerated') courses and to postgraduate degree planning and higher education certificate or diploma courses for other dental care professionals (auxiliaries). The report may have a European bias as progress is made to converge and enhance educational standards in 29 countries with different educational approaches - a microcosm of global collaboration.

The effect of image content on detail preservation and file size reduction in lossy compression.

OBJECTIVES: To demonstrate the effect of image content on image detail preservation and file size reduction. METHODS: The first set, containing 16 in vitro images with variable projection geometry, exposure time, bone level and number of teeth, was compressed with three compression modes: JPEG quality factor (JPQF), JPEG2000 quality factor (J2QF) and JPEG2000 compression ratio (J2CR). Image detail degradation was evaluated by local mean square error (MSE) on a standardized region of interest (ROI), containing bone. The second set, containing 105 clinical bitewings, was compressed with the same compression modes at 3 quality factors/compression ratios and local MSEs were calculated on two ROIs, containing bone and crown. RESULTS: For the first image set, nearly constant MSE was found for the JPQF and J2QF compression modes, while file size depended on projection geometry, exposure time, bone level and the number of teeth. In contrast, file size reduction was nearly constant for the J2CR compression mode, while MSE depended on the abovementioned factors. Similarly, for the second image set, nearly constant MSE and variation of file size reduction were found for JPQF and J2QF but not for the J2CR compression mode. All of these results were consistent for all three quality factors/compression ratios. CONCLUSIONS: Constant image detail preservation, crucial for diagnostic accuracy in radiology, can only be assured in QF compression mode in which the file size of the compressed image depends on the original image content. CR compression mode assures constant file size reduction, but image detail preservation depends on image content.

Lossy JPEG compression: easy to compress, hard to compare.

OBJECTIVES: To review the literature on lossy compression in dental radiography and to discuss the importance and suitability of the methodology used for evaluation of image compression. METHODS: A search of Medline (from 1966 to October 2004) was undertaken with the search expression "(Radiography, dental) and compression". Inclusion criterion was that the reference should be evaluating the effect of lossy image compression on diagnostic accuracy. For all included studies, information in relation to mode of image acquisition, image content, image compression, image display, and method of image evaluation was extracted. RESULTS: 12 out of 32 papers were included in the review. The design of these 12 studies was found to vary considerably. Parameters used to express the degree of information loss (DIL) were either or both compression ratio (CR) and compression level (CL). The highest acceptable CR reported in the studies ranged from 3.6% to 15.4%. Furthermore, different CR values were proposed even for the same diagnostic task, for example, for caries diagnosis CR ranged from 6.2% to 11.1%. CONCLUSION: Lossy image compression can be used in clinical radiology if it does not conflict with national law. However, the acceptable DIL is difficult to express and standardize. CR is probably not suitable to express DIL, because it is image content dependent. CL is also probably not suitable to express DIL because of the lack of compression software standardization.

Prevalence of some herpesviruses in gingival crevicular fluid.

BACKGROUND: The herpesviruses, ancient pathogens which have co-evoluted with human, are etiologically associated with a number of diseases, from asymptomatic to oncogenic and mortal diseases. It seems that some of them have also an important role in the pathogenesis of human periodontal disease. OBJECTIVE: This study aimed to determine the prevalence of Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), human herpesvirus 8 (HHV-8) and human cytomegalovirus (HCMV) in gingival crevicular fluid (GCF) and, eventually, to find the correlation between specific virus types and clinical parameters which are important in periodontitis, like plaque index (PI), gingival index (GI) and probing depth (PD). STUDY DESIGN: A polymerase chain reaction (PCR) and digestion of PCR products with restriction endonuclease were employed to identify the presence of EBV, HHV-6, HHV-8 and HCMV. RESULTS: Out of 66 samples of GCF taken from the patients with periodontal disease, EBV was found in 29 (43.9%), HHV-6 in 16 (24.2%) and HCMV in 2 (3%) samples, while in the samples of healthy persons, these viruses were not found. HHV-8 was detected neither in the patients with periodontitis nor in healthy control group. More positive results were found in clinical samples taken from people with higher PI and GI and in the samples taken from the patients with medium PD (PD=3-6mm). In all HHV-6 positive samples, we found only variant A; as for EBV positive samples, type A and type B were identified and also co-infection with the two types. It seems that there is a correlation between PI, PD and EBV types, but no correlation was found between EBV types and GI or HHV-6 types and PI, PD, GI. CONCLUSIONS: The present findings confirm some association between herpesviruses and human periodontitis.

Effects of periodontal dressings on fibroblasts and gingival wound healing in dogs.

In the present study the effects of different commercially available periodontal dressings (Peripac, Barricaid, Fittydent, Reso-Pack and Myzotect-tincture) on fibroblast (V-79-379A) proliferation and survival were tested in vitro. Barricaid, Fittydent and Reso-Pack periodontal dressings have only small inhibitory effects on cell proliferation (83.3 +/- 9%, 71.6 +/- 8.7% and 87.3 +/- 4.5% of control after 48 h, respectively) in comparison with the great inhibitory effect of Myzotect-tincture (2.9 +/- 0.1%) and Peripac (33.7 +/- 11.4%) (p < 0.001). Barricaid was the only dressing where 41% of cells survived after exposure, while the other four dressings killed all the cells in 6 days. In addition, the healing of artificially created gingival wounds covered by Barricaid and Reso-Pack was followed for 7 days in 12 Beagle dogs. Histological evaluation of gingival tissue demonstrated that wounds covered by Reso-Pack showed the best epithelisation and vascularity and the least inflammatory reaction in first 4 days. Later the observed parameters were similar with those of wounds covered by Barricaid or without pack. The present results indicate that Peripac periodontal dressing and Myzotect-tincture showed the highest cytotoxicity to fibroblasts in vitro. From the histological observations in Beagle dogs Reso-Pack has been found to be the most suitable dressing, followed by Barricaid.

The IgG antibody profile to various antigen regions of hepatitis C virus differs in oral fluid and serum of patients with chronic hepatitis C.

Antibodies to hepatitis C virus (HCV) can be detected not only in serum but also in oral fluid. The aim of the study was to determine IgG antibody reactivity directed to six antigen regions of HCV in oral fluid and to evaluate the significance of the antibody pattern in oral fluid compared to serum. Oral fluid and serum samples of 32 HCV viremic patients were collected to detect antibodies to six antigen regions incorporated as antigen bands into modified commercial updated third generation line immuno-assay. Compared to serum, a significantly lower cumulative antibody response and reactivity to five HCV antigens was found in oral fluid. The significantly highest prevalence of oral fluid reactivity was recorded with antigen C1 (78%), whereas in serum the most significantly frequent reactivity was detected with antigen NS3 (100%). The absence of antibody reactivity with antigen E2 was similar in both body fluids. The discrepancy in antibody pattern to HCV antigens between oral fluid and serum indicates the possible existence of local viral replication, viral mutants, viral inhibitors in oral cavity and, most probably, leakage of the muco-vascular barrier.

Immunolocalization of inducible nitric oxide synthase in localized juvenile periodontitis patients.

Localized juvenile periodontitis (LJP) is associated with a destruction of periodontal tissues and the presence of Actinobacillus actinomycetemcomitans (AA). Lipopolysaccharide (LPS) from AA was found to induce a significant macrophage production of nitric oxide (NO). Increased nitric oxide synthase (NOS) activity was found to be negatively correlated with the neutrophil chemotactic response. The aim of this study was to determine the occurrence and distribution of inducible NOS (iNOS) in human gingival tissue from LJP patients. The distribution of iNOS was assessed by monoclonal antibody against iNOS. Cellular markers (CD 3, CD 20, and CD 68) were used to determine the cellular origin of iNOS. The immunostaining revealed the appearance of iNOS in inflamed compared to noninflamed gingival tissues. Macrophages expressed high levels of iNOS that may cause some damage to the periodontal tissues. This study suggests that iNOS activity in macrophages may modify abnormalities of neutrophil function.

Comparative evaluation of JPEG and JPEG2000 compression in quantitative digital subtraction radiography.

OBJECTIVES: The aim of this in vitro study was to compare the impact of JPEG and the novel JPEG2000 compression standard on quantitative digital subtraction radiography (DSR) and to determine the acceptable JPEG2000 compression ratios for DSR. METHODS: Nine dry pig mandible sections were radiographed three times ('Baseline', 'No change', and 'Gain') with standardized projection geometry. Bone gain was simulated by adding artificial bone chips (1, 4 and 15 mg). Images were registered, compressed by JPEG and JPEG2000 using compression ratios (CR) of 1 : 7, 1 : 16, 1 : 22, and 1 : 31, and then subtracted. Image distortion was assessed objectively by calculating average pixel error and peak signal to noise ratio. No change areas in compressed and subtracted 'No change-Baseline' images and bone gain volumes in compressed and subtracted 'Gain-Baseline' images were calculated for both compression standards and compared. RESULTS: JPEG introduced less distortion at low CRs, while JPEG2000 was superior at higher CRs. At CR of 1 : 7, no significant difference between JPEG and JPEG2000 was found. JPEG2000 yielded better results for no change measurements at higher CRs. Volumes of simulated bone gain were overestimated when JPEG and underestimated when JPEG2000 compression was used. CONCLUSIONS: At CR of 1 : 7 JPEG and JPEG2000 performed similarly, which indicates that CR of 1:7 in JPEG2000 can be used for DSR if images are registered before compression. At higher CRs, JPEG2000 is superior to JPEG but image distortions are too high for reliable quantitative DSR.

Impact of JPEG lossy image compression on quantitative digital subtraction radiography.

OBJECTIVES: The aim of the study was to evaluate the impact of JPEG lossy image compression on the estimation of alveolar bone gain by quantitative digital subtraction radiography (DSR). METHODS: Nine dry domestic pig mandible posterior segments were radiographed three times ('Baseline', 'No change', and 'Gain') with standardized projection geometry. Bone gain was simulated by adding artificial bone chips (1, 4, and 15 mg). Images were either compressed before or after registration. No change areas in compressed and subtracted 'No change-Baseline' images and bone gain volumes in compressed and subtracted 'Gain-Baseline' images were calculated and compared to the corresponding measurements performed on original subtracted images. RESULTS: Measurements of no change areas ('No change-Baseline') were only slightly affected by compressions down to JPEG 50 (J50) applied either before or after registration. Simulated gain of alveolar bone ('Gain-Baseline') was underestimated when compression before registration was performed. The underestimation was bigger when small bone chips of 1 mg were measured and when higher compression rates were used. Bone chips of 4 and 15 mg were only slightly underestimated when using J90, J70, and J50 compressions before registration. CONCLUSIONS: Lossy JPEG compression does not affect the measurements of no change areas by DSR. Images undergoing subtraction should be registered before compression and if so, J90 compression with a compression ratio of 1:7 can be used to detect and measure 4 mg and larger bone gain.

The change of DMFT counts in Slovenia.

This longitudinal study was designed to assess the change in caries prevalence and DMFT counts in the adult population of Ljubljana, Slovenia, over a 10-year period. All data in the present study are derived from two surveys conducted in 1983-1987 and 1993-1997. In the first survey, 1,609 dentate subjects in the range from 15 to 65 years were examined. Ten years later, 555 (34.5%) of these subjects participated in the second oral survey. In the 538 dentate 25- to 75-year-old subjects examined in the second survey, a decline in the mean number of decayed teeth (1.1 vs. 0.5) was found, and an increase in DMFT counts (15.9 vs. 19.1) due to a higher number of missing (5.2 vs. 7.5) and filled teeth (9.7 vs. 11.1) was observed. However, a comparison with the previous generation of the same age showed a decline in the average number of decayed and missing teeth in all age groups and an increase in the mean number of filled teeth in all age groups as well. The population of Ljubljana from the 1993-1997 survey had retained in most of the age groups about 2 teeth more than had the generation 10 years before.

Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiation.

OBJECTIVES: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. MATERIAL AND METHODS: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80 mJ/p and 100 mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. RESULTS: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. CONCLUSION: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins.

Detection of hepatitis C virus RNA from gingival crevicular fluid and its relation to virus presence in saliva.

BACKGROUND: To search for a possible source of hepatitis C virus (HCV) in saliva, the presence and shedding patterns of HCV in gingival crevicular fluid (GCF) and saliva of HCV viremic patients were assessed based on clinical, biochemical, histological, virological, and oral health parameters. METHODS: Saliva and GCF samples of 50 HCV viremic patients were collected to detect HCV RNA by a modified commercial polymerase chain reaction (PCR) assay. Clinical oral examination was performed and periodontal status at the collection sites was monitored. The results were correlated to specified parameters. RESULTS: HCV RNA was detected in 59% (29/49) of the GCF specimens and in 35% (17/48) of the saliva specimens. In saliva specimens, HCV RNA was detected only in cases which also had detectable HCV RNA in the GCF samples (P=0.00002) and was significantly related to the presence of blood in saliva (P=0.03). Higher, but not significant, values of oral clinical parameters at the sites of fluid collection were found in GCF specimens harboring HCV RNA. In GCF specimens with no blood detected, HCV RNA was more often present in cases with higher plasma viral load (P=0.05). CONCLUSIONS: The results suggest that besides blood, the other most probable source of HCV in saliva is GCF. Unknown endogenous HCV inhibitory mechanisms in the oral cavity may explain the discrepancies in HCV appearance between saliva and GCF. The results provide a biologic basis for further investigation of the role of HCV in the pathogenesis of periodontal disease.

Proviral HIV-1 DNA in gingival crevicular fluid of HIV-1-infected patients in various stages of HIV disease.

The oral cavity is rarely reported to be a site of human immunodeficiency virus (HIV) transmission, despite detectable virus in saliva and relatively frequent prevalence of periodontal disease in HIV-infected persons yielding increased excretion of mononuclear-cell-enriched gingival fluid. To search for possible sources of HIV in saliva, and using the polymerase chain-reaction technique, we sought the presence and shedding patterns of proviral HIV-1 DNA in gingival crevicular fluid in a group of patients previously determined as HIV-1-seropositive. Periodontal status at the collection sites was monitored by several clinical parameters, including Plaque Index, Gingival Index, probing depth, and clinical attachment loss. Gingival crevicular fluid samples were collected by means of paper points. Proviral HIV-1 DNA was detected in the gingival fluid of 17 out of 35 HIV-1-infected patients. Its detection correlated significantly with higher plasma HIV-1 RNA viral load (p = 0.03) and not with peripheral blood CD4+ cell count, the presence of blood in gingival fluid, or oral lesions. There was a significant correlation between clinical attachment loss at the sites of fluid collection and plasma HIV-1 RNA viral load (p = 0.002), and borderline correlation between the latter and probing depth (p = 0.54) in the group of patients harboring proviral HIV-1 DNA in gingival crevicular fluid. The results of our study suggest that mononuclear cells present in gingival crevicular fluid and harboring proviral HIV-1 DNA could represent a potential source of HIV-1 in the presence or absence of local bleeding, especially in persons with advanced HIV infection and increased loss of clinical attachment.

The prevalence of oral mucosal lesions in a population in Ljubljana, Slovenia.

The purpose of the present study was to evaluate the prevalence of oral mucosal lesions and conditions in a population in Ljubljana, capital of Slovenia. A total 1609 subjects represented the study population in the survey about the periodontal treatment needs in a population in Ljubljana, conducted from 1983 to 1987. Ten years later the same 1609 subjects were invited to the second examination. Altogether, 555 (34.5%) of the invited subjects in the age range 25-75 years came for an interview and clinical examination at the Department of Oral Medicine and Periodontology of the Dental Clinic in Ljubljana. Oral mucosal lesions and conditions were evaluated according to the WHO Guide to Epidemiology and Diagnosis of Oral Mucosal Diseases and Conditions. The results showed the presence of one or more mucosal lesions in 61.6% of the population. Fordyce's condition was observed the most frequently (49.7%) followed by: fissured tongue (21.1%), varices (16.2%), history of herpes labialis (16.0%), history of recurrent aphthae (9.7%), denture stomatitis (4.3%), leukoplakia (3.1%), cheek biting (2.7%), lichen planus (2.3%), frictional keratosis (2.2%), geographic tongue (2.2%), geographic and fissured tongue together (1.1%), mucocele (0.9%), smoker's palate (0.5%) and angular chelitis (0.4%). In the population examined, no oral malignancies were observed. Mucosal lesions like whitish lesions, denture related lesions, fissured tongue, varices and mucocele were more prevalent with increasing age. Tobacco-related lesions (leukoplakia and smoker's palate together) were significantly more prevalent among men than among women (P<0.05), while lichen planus, denture stomatitis and herpes labialis occurred more frequently in the female population.

Influence of developer exhaustion on accuracy of quantitative digital subtraction radiography: an in vitro study.

OBJECTIVE: The aim of the study was to evaluate the influence of developer exhaustion on accuracy of quantitative digital subtraction radiography. STUDY DESIGN: Six objects, each incorporating a section of dry human mandible, were radiographed with 4 exposure times. Baseline films were processed in fresh solutions, whereas follow-up films were processed in fresh and in increasingly exhausted solutions (ie, 1, 2, and 3 weeks old). Bone loss and bone gain were computer simulated in 17 regions of interest on baseline radiographs. Area and volume of changes in mineralization were measured in subtracted images, obtained by subtraction of baseline from their corresponding follow-up radiographs. Friedman's 2-way analysis of variance by ranks and Wilcoxon signed-rank test were used for statistical analysis. RESULTS: Because of exhausted developer, bone loss was relatively underestimated from 6.6% to 16.5% (P <.05), whereas bone gain was relatively overestimated from 9.7% to 16.7% (P <.05). CONCLUSIONS: This in vitro study demonstrates that films for quantitative digital subtraction radiography should be processed in fresh developer or error might be introduced.

Superoxide release and superoxide dismutase expression by human gingival fibroblasts.

Oxygen reactive intermediates released from phagocytic cells are important for microbicidal activity, but they may also be harmful to surrounding cells and matrix components at the inflammation site. In different forms of inflammatory periodontal disease, peripheral and crevicular polymorphonuclear leukocytes, as well as mononuclear phagocytes and gingival fibroblasts, are exposed to bacterial cell wall components and cytokines. The aim of this study was to evaluate if some bacterial components and cytokines induce superoxide release and superoxide dismutase (SOD) expression in gingival fibroblasts. Lipopolysaccharide (LPS), streptococcal cell walls (SCW), and formyl-methionyl-leucyl-phenylalanine were found to stimulate O2- release from gingival fibroblasts, which increased when Ca2+ was added. Phorbol myristate acetate, a potent activator of respiratory burst in phagocytes, was found to be a weak stimulator of O2- release in gingival fibroblasts. Of the cytokines tested, tumor necrosis factor (TNF)-alpha was found to activate superoxide release in gingival fibroblasts. Gene expression for manganese superoxide dismutase (MnSOD), but not for copper/zinc superoxide dismutase (CuZnSOD), was demonstrated in fibroblasts exposed to LPS, SCW and TNF-alpha using Northern blot analysis. The production of MnSOD may be protective for these cells. We conclude that bacterial cell wall components and cytokines modulate O2- release by gingival fibroblasts which may contribute to periodontal pathology.