Increased oxidative product formation by peripheral blood polymorphonuclear leukocytes in human periodontal diseases

Meta-Analysis of Assessment of Total Oxidative Stress and Total Antioxidant Capacity in Patients with Periodontitis

Background

Periodontitis is intricately linked to oxidative stress-antioxidant (redox) imbalance. The antioxidant system scavenges the oxygen free radicals in biological fluids in patients with periodontitis. However, little is still known about the free radicals mediated oxidative stress and reductive ability of the antioxidant system. Thus, the present meta-analysis aims to quantitatively review the literature that assessed the oxidative stress marker total oxidative stress (TOS) and total antioxidant capacity (TAC) in various biological fluids of patients with periodontitis. Methodology. Electronic databases were searched for studies that assessed TOS and TAC levels in various biological samples of patients with periodontitis.

Results

From the 1,812 articles identified, 1,754 were excluded based on title and abstract screening due to irrelevance to the topic of interest. A full-text assessment of the remaining 58 articles led to the selection of 42 articles that satisfied the inclusion criteria. Of these, only 24 studies had consistent data for quantitative analysis. The periodontitis group displayed significantly elevated TOS levels (p < 0.05) in serum, gingival crevicular fluid (GCF), and saliva samples in the studies evaluated. In contrast, the periodontitis group exhibited significantly attenuated TAC levels (p < 0.01) compared to healthy controls in plasma, serum, and GCF samples of the studies evaluated, which was insignificant in salivary samples (p=0.433). At the same time, the periodontitis group displayed insignificantly elevated TAC levels after periodontal therapy (p=0.130).

Conclusions

The present meta-analysis showed significantly higher TOS and lower TAC in periodontitis, reflecting the elevated oxidative stress level than the control group. Clinical Relevance. Scientific rationale for the study: The imbalance between oxidants and antioxidants (oxidative stress (OS)) plays a critical role in the onset and progression of periodontitis; the assessment of the relationship between OS-related biomarkers in regional samples and systemic samples of patients with periodontitis helps us to evaluate the periodontal disease progression. The OS biomarker levels can be used to assess periodontal disease and therapeutic efficacy.

Salivary Antioxidant Profile in Patients with Systemic Sclerosis and Periodontitis

Objective

The aim of the present study was to compare periodontal status and antioxidant profile in unstimulated saliva of systemic sclerosis (SSc) patients with periodontitis and systemically healthy periodontitis patients.

Design

Twenty patients with established diagnoses of systemic sclerosis and periodontitis (SSc group) and 20 systemically healthy individuals with periodontitis (P group) were enrolled in the study. Clinical periodontal parameters (clinical attachment level (CAL), gingival recession (GR), periodontal probing depth (PPD), and gingival index (GI)) and concentration of uric acid (UA), superoxide dismutase (SOD), and glutathione peroxidase (GPX) in unstimulated saliva samples were assessed.

Results

There were significantly higher mean values of CAL (4.8 ± 0.21 mm versus 3.18 ± 0.17 mm; p ≤ 0.001) and GR (1.66 ± 0.90 mm versus 0.46 ± 0.54 mm; p ≤ 0.001) in the SSc group when compared to the P group. Significantly higher level of GPX (p ≤ 0.001) and SOD (p ≤ 0.001) in unstimulated saliva was detected in the SSc group in comparison with the P group. The specific activity of UA did not significantly differ between the two groups (p = 0.083).

Conclusion

The results may indicate higher periodontal destruction and antioxidant perturbations in unstimulated saliva of SSc patients with periodontitis compared to systemically healthy periodontitis patients.

Comparative evaluation of 1% melatonin gel in the treatment of intrabony defect: A randomized controlled clinical trial

BACKGROUND

The present study aims to evaluate and compare the efficacy of locally delivered 1% melatonin gel as an adjunct to non-surgical periodontal therapy (NSPT) in treatment of intrabony defect in Stage III periodontitis, clinically, and radiographically using cone-beam computed tomography (CBCT).

METHODS

This split-mouth clinical trial randomly allotted 44 bilateral intrabony defect (in 22 patients) into two groups where Group I was treated with NSPT with locally delivered placebo gel while Group II was treated with NSPT with 1% melatonin gel. The intrabony defect fill measured from cemento-enamel junction (CEJ)-base of the defect (BD), and the difference in the measurement values of CEJ-BD from baseline to 6 months denoting the bone fill and bone volume evaluated at 6 months using CBCT were the primary outcome measures. Secondary outcome measures were change in probing depth (PD), clinical attachment level (CAL), plaque index, and modified sulcus bleeding index recorded at baseline, 3 months, and 6 months.

RESULTS

Both the study groups showed improvements in assessed parameters, however, a significant gain in intrabony defect fill was observed in Group II (1.46 ± 0.58) as compared with Group I (0.50 ± 0.38) and change in bone volume for Group I was 21.4645 ± 8.8980 mm³ and for Group II was 51.8418 ± 30.2329 mm³ with P < 0.0001.The mean reduction in PD and gain in CAL was 3.90 ± 0.78 and 2.94 ± 0.80 in Group II and in Group I it was 3.23 ± 0.90 and 1.96 ± 0.80 (P < 0.0001).

CONCLUSION

The use of 1% melatonin gel as an adjunct to NSPT is more beneficial in achieving better clinical and radiographic outcome at 6 months which indicates that adjunct use of melatonin gel to NSPT as a local drug delivery is preferred when compared with NSPT and placebo gel alone.

Association between gestational diabetes mellitus and periodontitis via the effect of reactive oxygen species in peripheral blood cells

BACKGROUND

Periodontitis (P) has emerged as a risk factor for gestational diabetes mellitus (GDM) through immune cell function alterations, elevated proinflammatory mediators, and increased reactive oxygen species (ROS). The main objective of present study was to determine associations between pregnancy with and without GDM and P. The secondary objective was to compare ROS production in peripheral blood cells (PBCs) of pregnant women with and without GDM.

METHODS

This cross-sectional case-control study included 128 pregnant women: 64 with and 64 without GDM. All participants were examined for clinical parameters of GDM and periodontal conditions. Associations between GDM-related periodontal data and GDM risk were evaluated by multiple logistic regression. PBCs were isolated and cultured. ROS productions in each PBCs types was investigated by flow cytometry with ROS antibodies.

RESULTS

P was significantly more prevalent in pregnant women with GDM than in those without GDM (57.8% versus 37.5%), with an odds ratio (OR) of 2.28, and a 95% confidence interval (CI) of 1.12 to 4.64 (P = 0.022). The OR (95% CI) was 2.59 (1.19 to 5.65) (P = 0.017) after adjusting for potential confounding factors, including diabetes mellitus (DM) family history, age ≥30 years, body mass index, and maternal age. ROS levels in all PBCs types were significantly higher in the GDM than in the non-GDM group (P < 0.05).

CONCLUSION

This study supported the association between P and GDM and indicated that P may be a risk factor for GDM. High levels of ROS production in the PBCs of pregnant women with GDM emphasized the association with GDM.

Effect of Non-surgical Periodontal Therapy on Salivary Melatonin Levels

Objective: Melatonin, a hormone secreted predominantly by pineal gland in a circadian manner, has antioxidant and anti-inflammatory effects. The current research is conducted to explore the influence of non-surgical periodontal therapy (NSPT) on levels of salivary melatonin in subjects with gingivitis and periodontitis. Methods: Sixty systemically healthy participants were included in this study; the groups are as follows: gingivitis (G), chronic periodontitis (CP), generalized aggressive periodontitis (GAP) and periodontally healthy (H). NSPT was applied to G group patients for 2 sessions, to CP and GAP group patients for 4 sessions. Plaque and gingival indices, probing depth (PD), bleeding on probing (BOP), and clinical attachment level (CAL) were documented at baseline and 3 months post – treatment and early morning salivary samples were collected. ELISA was used to detect melatonin levels in saliva. Pittsburgh Sleep Quality Index (PSQI) questionnaire was performed to evaluate of sleep quality of patients. Results: At baseline, significant difference in gingival index, PD, BOP and CAL values was detected among all groups (p

Circulating inflammatory cell profiling and periodontitis: A systematic review and meta-analysis

Inflammation is a key driver of common noncommunicable diseases. Among common triggers of inflammation, chronic gingival inflammation (periodontitis) triggers a consistent humoral host inflammatory response, but little is known on its impact on circulating inflammatory cell profiles. We aimed to systematically appraise all the evidence linking periodontitis and its treatment to circulating inflammatory cell profiles. From 6 databases, 157 studies were eligible for qualitative synthesis and 29 studies for meta-analysis. Our meta-analysis showed that participants with periodontitis exhibited a significant mean increase in circulating CD4⁺ , CD4⁺ CD45RO⁺ , IFNγ-expressing CD4⁺ and CD8⁺ T cells, CD19⁺ CD27⁺ and CD5⁺ B cells, CD14⁺ CD16⁺ monocytes, and CD16⁺ neutrophils but decrease in CD8⁺ T and CD14⁺⁺ CD16^- monocytes. Our qualitative synthesis revealed that peripheral blood neutrophils of patients with periodontitis consistently showed elevated production of reactive oxygen species (ROS) when compared with those of healthy controls. Some evidence suggested that the treatment of periodontitis reversed the exaggerated ROS production, but limited and inconclusive data were found on several circulating inflammatory cell profiling. We conclude that periodontitis and its treatment are associated with minor but consistent alterations in circulating inflammatory cell profiles. These changes could represent key mechanisms explaining the association of periodontitis with other comorbidities such as cardiovascular disease, diabetes, and rheumatoid arthritis.

Influence of Electronic Cigarettes on Antioxidant Capacity and Nucleotide Metabolites in Saliva

The balance between reactive oxygen species production and the activity of antioxidant systems present in saliva is an important element in maintaining oral environment homeostasis. E-cigarettes adversely affect the oral cavity and their cytotoxic effect is related to oxidative stress. The aim of this study was to assess the influence of using electronic cigarettes on antioxidant capacity of saliva. The study involved 110 subjects (35 e-cigarettes users, 33 traditional cigarettes smokers and 42 non-smokers). Laboratory analysis involved quantitation of uric acid, hypoxanthine, xanthine, TAOS (total antioxidant status) and TEAC (Trolox equivalent antioxidant capacity) in saliva. Lower values for TAOS and TEAC were observed among e-cigarettes users and traditional cigarettes smokers in comparison to non-smokers. Uric acid concentration tended to be higher among e-cigarettes users while no differences in hypoxanthine and xanthine saliva concentrations were observed. Electronic cigarettes usage affects antioxidant capacity of saliva to the same extent as traditional cigarettes, when comparing smokers to non-smokers. Further longitudinal studies on a larger study group are needed to assess the effect of changes in antioxidant status on oral health.

Relationship between Periodontitis and Glaucoma: A Cross-Sectional Study

The objective of this cross-sectional study was to evaluate the association between periodontitis and glaucoma. This prospective cohort study used epidemiological data from the Korean Genome and Epidemiology Study performed between 2004 and 2016. Among 173,209 participants, 9572 patients with periodontitis and 115,332 controls (nonperiodontitis) were selected. We analysed the history of glaucoma in periodontitis and control participants. The participants were interviewed regarding their history of hypertension, diabetes mellitus, hyperlipidaemia, periodontitis, glaucoma, smoking, and alcohol consumption by trained interviewers. A logistic regression model was created to analyse the odds ratio of having a history of glaucoma among patients with periodontitis. Two-tailed analyses using chi-square and independent t-tests were used for statistical analysis. The adjusted odds ratio of periodontitis as a risk factor for glaucoma was 3.44 (95% confidence interval = 2.99–3.97, $p<0.001$ ). This study demonstrated that glaucoma was associated with periodontitis.

Total Oxidant and Antioxidant Capacity of Gingival Crevicular Fluid and Saliva in Patients with Periodontitis: Review and Clinical Study

Periodontitis is inextricably linked to oxidative-reductive (redox) imbalance. However, little is still known about the resultant ability to scavenge oxygen free radicals in saliva and gingival crevicular fluid in patients with periodontitis. The multitude of enzymatic and non-enzymatic antioxidants and their synergistic effects cause an interest in the evaluation of the total antioxidative capacity. Thus, our study aimed to evaluate the total oxidative and antioxidative activity of gingival crevicular fluid and saliva in the periodontitis, as well as to relate these biomarkers to clinical indices of periodontopathy. Additionally, by calculating the oxidative stress index (OSI), the intensity of redox disturbances was also evaluated. Fifty-eight periodontitis patients were included in the study and divided into two subgroups depending on the severity of the disease. In the non-stimulated/stimulated saliva as well as a gingival crevicular fluid of the study group, we found significantly higher OSI and total oxidant status (TOS) as well as lower total antioxidant capacity (TAC). However, the ability to reduce iron ions (FRAP) was significantly lower only in stimulated and non-stimulated saliva of patients with periodontitis. The examined parameters correlated with the periodontium’s clinical condition, which indicates the exacerbation of the inflammatory process. However, TAC, TOS, OSI, and FRAP did not differentiate individual stages of periodontitis.

The protective effect of myo-inositol on human thyrocytes

Patients affected by autoimmune thyroiditis reached positive effects on indices of thyroid autoimmunity and/or thyroidal function, after following a treatment with selenomethionine (Se) alone, or Se in combination with Myo-inositol (Myo-Ins). Our purpose was to investigate if Myo-Ins alone, or a combination of Se + Myo-Ins, is effective in protecting thyroid cells from the effects given by cytokines, or hydrogen peroxide (H₂O₂). We assessed the interferon (IFN)-γ-inducible protein 10 (IP-10/CXCL10) secretion by stimulating primary thyrocytes (obtained from Hashimoto's thyroiditis or from control patients) with cytokines in presence/absence of H₂O_2. Our results confirm: 1) the toxic effect of H₂O₂ in primary thyrocytes that leads to an increase of the apoptosis, to a decrease of the proliferation, and to a slight reduction of cytokines-induced CXCL10 secretion; 2) the secretion of CXCL10 chemokine induced by IFN-γ + tumor necrosis factor alpha (TNF)-α has been decreased by Myo + Ins, both in presence or absence of H₂O₂; 3) no effect has been shown by the treatment with Se. Therefore, a protective effect of Myo-Ins on thyroid cells has been suggested by our data, which exact mechanisms are at the basis of this effect need to be furtherly investigated.

Effects of Melatonin and Its Underlying Mechanism on Ethanol-Stimulated Senescence and Osteoclastic Differentiation in Human Periodontal Ligament Cells and Cementoblasts

The present study evaluated the protective effects of melatonin in ethanol (EtOH)-induced senescence and osteoclastic differentiation in human periodontal ligament cells (HPDLCs) and cementoblasts and the underlying mechanism. EtOH increased senescence activity, levels of reactive oxygen species (ROS) and the expression of cell cycle regulators (p53, p21 and p16) and senescence-associated secretory phenotype (SASP) genes (interleukin [IL]-1β, IL-6, IL-8 and tumor necrosis factor-α) in HPDLCs and cementoblasts. Melatonin inhibited EtOH-induced senescence and the production of ROS as well as the increased expression of cell cycle regulators and SASP genes. However, it recovered EtOH-suppressed osteoblastic/cementoblastic differentiation, as evidenced by alkaline phosphatase activity, alizarin staining and mRNA expression levels of Runt-related transcription factor 2 (Runx2) and osteoblastic and cementoblastic markers (glucose transporter 1 and cementum-derived protein-32) in HPDLCs and cementoblasts. Moreover, it inhibited EtOH-induced osteoclastic differentiation in mouse bone marrow⁻derived macrophages (BMMs). Inhibition of protein never in mitosis gene A interacting-1 (PIN1) by juglone or small interfering RNA reversed the effects of melatonin on EtOH-mediated senescence as well as osteoblastic and osteoclastic differentiation. Melatonin blocked EtOH-induced activation of mammalian target of rapamycin (mTOR), AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK) and Nuclear factor of activated T-cells (NFAT) c-1 pathways, which was reversed by inhibition of PIN1. This is the first study to show the protective effects of melatonin on senescence-like phenotypes and osteoclastic differentiation induced by oxidative stress in HPDLCs and cementoblasts through the PIN1 pathway.

Oxidative Stress and Antioxidants in the Diagnosis and Therapy of Periodontitis

Oxidative stress has been implicated in the pathogenesis of numerous diseases. However, large interventional studies with antioxidants failed to show benefits in the prevention or treatment of cardiovascular diseases, cancer, or diabetes mellitus. Numerous clinical studies have confirmed the association of oxidative stress markers and periodontitis. Technical and biological variability is high for most of the analyzed markers and none of them seems to be optimal for routine clinical use. In a research setting, analysis of a palette of oxidative stress markers is needed to cover lipid peroxidation, protein oxidation, and the antioxidant status. The source of reactive oxygen species and their role in the pathogenesis of periodontitis remains unclear. Interventional experiments indicate that oxidative stress might be more than just a simple consequence of the inflammation. Small studies have confirmed that some antioxidants could have therapeutic value at least as an addition to the standard non-surgical treatment of periodontitis. A clear evidence for the efficiency of antioxidant treatment in large patient cohorts is lacking. Potentially, because lowering of oxidative stress markers might be a secondary effect of anti-inflammatory or antibacterial agents. As the field of research of oxidative stress in periodontitis gains attraction and the number of relevant published papers is increasing a systematic overview of the conducted observational and interventional studies is needed. This review summarizes the currently available literature linking oxidative stress and periodontitis and points toward the potential of adjuvant antioxidant treatment, especially in cases where standard treatment fails to improve the periodontal status.

Nrf2 Inhibits Periodontal Ligament Stem Cell Apoptosis under Excessive Oxidative Stress

The present study aimed to analyze novel mechanisms underlying Nrf2-mediated anti-apoptosis in periodontal ligament stem cells (PDLSCs) in the periodontitis oxidative microenvironment. We created an oxidative stress model with H₂O₂-treated PDLSCs. We used real-time PCR, Western blotting, TUNEL staining, fluorogenic assay and transfer genetics to confirm the degree of oxidative stress and apoptosis as well as the function of nuclear factor-erythroid 2-related factor 2 (Nrf2). We demonstrated that with upregulated levels of reactive oxygen species (ROS) and malondialdehyde (MDA), the effect of oxidative stress was obvious under H₂O₂ treatment. Oxidative molecules were altered after the H₂O₂ exposure, whereby the signaling of Nrf2 was activated with an increase in its downstream effectors, heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1) and γ-glutamyl cysteine synthetase (γ-GCS). Additionally, the apoptosis levels gradually increased with oxidative stress by the upregulation of caspase-9, caspase-3, Bax and c-Fos levels in addition to the downregulation of Bcl-2. However, there was no alterations in levels of caspase-8. The enhanced antioxidant effect could not mitigate the occurrence of apoptosis. Furthermore, Nrf2 overexpression effectively improved the anti-oxidative levels and increased cell proliferation. At the same time, overexpression effectively restrained TUNEL staining and decreased the molecular levels of caspase-9, caspase-3, Bax and c-Fos, but not that of caspase-8. In contrast, silencing the expression of Nrf2 levels had the opposite effect. Collectively, Nrf2 alleviates PDLSCs via its effects on regulating oxidative stress and anti-intrinsic apoptosis by the activation of oxidative enzymes.

Melatonin: A Review of Its Potential Functions and Effects on Dental Diseases

Melatonin is a hormone synthesised and secreted by the pineal gland and other organs. Its secretion, controlled by an endogenous circadian cycle, has been proven to exert immunological, anti-oxidant, and anti-inflammatory effects that can be beneficial in the treatment of certain dental diseases. This article is aimed at carrying out a review of the literature published about the use of melatonin in the dental field and summarising its potential effects. In this review article, an extensive search in different databases of scientific journals was performed with the objective of summarising all of the information published on melatonin use in dental diseases, focussing on periodontal diseases and dental implantology. Melatonin released in a natural way into the saliva, or added as an external treatment, may have important implications for dental disorders, such as periodontal disease, as well as in the osseointegration of dental implants, due to its anti-inflammatory and osseoconductive effects. Melatonin has demonstrated to have beneficial effects on dental pathologies, although further research is needed to understand the exact mechanisms of this molecule.

Effects of an ascorbic acid-derivative dentifrice in patients with gingivitis: a double-masked, randomized, controlled clinical trial

BACKGROUND

Reactive oxygen species might be associated with the onset and progression of gingival inflammation. The aim of this study is to investigate the effect of a dentifrice containing L-ascorbic acid 2-phosphate magnesium salt (APM), a long-acting ascorbic acid derivative with antioxidant properties, on gingival inflammation.

METHODS

The clinical effects of APM were investigated in a multicenter, randomized, parallel-group, controlled clinical trial comprising 300 individuals with gingivitis. Half of the participants were given an APM-containing dentifrice and half were given a control dentifrice. The primary outcome was the gingival index (GI) at 3 months. Secondary outcomes included gingival redness as an indicator of the degree of local gingival inflammation, gingival bleeding as a measure of the gingivitis severity index, and total antioxidant activity of the saliva.

RESULTS

Under the intent-to-treat analysis, GI did not significantly differ between the groups (P = 0.12). However, under the per-protocol analysis, GI was significantly lower in the APM group (P = 0.01) than in the control group. In the APM group, gingival redness was significantly lower, and the difference from the baseline gingivitis severity index was significantly greater (P = 0.04 and P = 0.02, respectively). The total antioxidant activity of the saliva was significantly higher in the APM group (P = 0.03). The incidence of adverse events did not significantly differ between the groups (P > 0.15).

CONCLUSION

These findings indicate that the regular application of an APM-containing dentifrice could reduce gingival inflammation.

Evaluation of melatonin levels in saliva in gingivitis and periodontitis cases: A pilot study

Objective:

To evaluate the melatonin levels in saliva in gingivitis and periodontitis cases.

Background:

Melatonin has strong antioxidant, free radical scavenging, and immunomodulating properties, acts on osteoblasts directly to stimulate cell proliferation and synthesis of Type I collagen, and promotes bone formation.

Materials and Methods:

A total of thirty participants were selected and divided into three groups (control group, gingivitis group, and periodontitis group). In each group, ten participants were taken. Salivary melatonin was estimated in each of the three groups.

Results:

Results from this study showed that the mean levels of salivary melatonin increased as severity increased from control to periodontitis, i.e., the mean levels were highest in periodontitis followed by gingivitis and least in control group. The melatonin level of all participants was positively and significantly (P < 0.01) correlated with their gingival index (r = 0.85, P < 0.01) and probing depth (r = 0.72, P < 0.01).

Conclusion:

Salivary melatonin level varied with the severity of gingivitis and periodontitis. With increased severity of periodontal disease, the level of salivary melatonin also increased suggesting that salivary melatonin may act as a diagnostic biomarker for periodontal diseases.

Proteomic analysis of gingival crevicular fluid for discovery of novel periodontal disease markers

The protein composition of gingival crevicular fluid (GCF) may reflect the pathophysiology of periodontal diseases. A standard GCF proteomic pattern of healthy individuals would serve as a reference to identify biomarkers of periodontal diseases by proteome analyses. However, protein profiles of GCF obtained from apparently healthy individuals have not been well explored. As a step toward detection of proteomic biomarkers for periodontal diseases, we applied both gel-based and gel-free methods to analyze GCF obtained from healthy subjects as compared with supragingival saliva. To ensure optimized protein extraction from GCF, a novel protocol was developed. The proteins in GCF were extracted with high yield by urea buffer combined with ultrafiltration and the intensity of spots with supragingival saliva and GCF was compared using agarose two-dimensional electrophoresis. Eight protein spots were found to be significantly more intense in GCF. They included superoxide dismutase 1 (SOD1), apolipoprotein A-I (ApoA-I), and dermcidin (DCD). Moreover, GCF proteins from healthy subjects were broken down into small peptide fragments and then analyzed directly by LC-MS/MS analysis. A total of 327 proteins including ApoA-I, SOD1, and DCD were identified in GCF. These results may serve as reference for future proteomic studies searching for GCF biomarkers of periodontal diseases.

Melatonin levels in periodontal health and disease

BACKGROUND AND OBJECTIVE

The aim of this study was to measure melatonin levels in the gingival crevicular fluid and saliva of subjects with healthy periodontal tissues, plaque-induced gingival inflammation, chronic periodontitis and aggressive periodontitis.

MATERIAL AND METHODS

A total of 70 subjects were examined and assigned to four groups: healthy periodontium (10 subjects); plaque-induced gingival inflammation (20 subjects); chronic periodontitis (20 subjects); and aggressive periodontitis (20 subjects). Gingival crevicular fluid and saliva samples were collected from each subject and analyzed using ELISAs.

RESULTS

The melatonin levels in both gingival crevicular fluid and saliva were lower in patients with chronic periodontitis (10.4 and 12.8 pg/mL, respectively) and aggressive periodontitis (8.4 and 8.8 pg/mL, respectively) than in patients with gingivitis (13.9 and 17.6 pg/mL, respectively) and in healthy subjects (16.6 and 22.9 pg/mL, respectively). The mean melatonin levels in both gingival crevicular fluid and saliva were statistically significantly higher in healthy patients compared with patients with chronic periodontitis and aggressive periodontitis; however, there was no significant difference in the plaque-induced gingival inflammation between the study groups.

CONCLUSIONS

The melatonin levels in gingival crevicular fluid and saliva are decreased in diseased periodontal tissues, especially periodontitis. The melatonin level was lowest in the aggressive periodontitis group.

Oxidative stress caused by a low concentration of hydrogen peroxide induces senescence-like changes in mouse gingival fibroblasts

Periodontal tissue deteriorates under persistent oxidative stress induced by inflammatory reactions in the microflora of the oral cavity. This study aimed to evaluate the cellular properties of mouse gingival fibroblasts (MGFs) in the presence of oxidative stress. MGFs from 10-, 30- and 52-week-old mice were used to evaluate the changes in the cellular properties with aging. The study investigated the effects of oxidative stress on the cellular properties of MGFs from 10-week-old mice. The expression of p53, p21 and murine double minute 2 (Mdm2) in the MGFs in response to oxidative stress was also examined. By day 8, the number of MGFs increased in culture. However, the increase was markedly lower in MGFs derived from aged mice. Oxidative stress due to hydrogen peroxide (H2O2)-induced morphological changes characterized by a round shape with enlarged nuclei and expanded cytoplasm. The cell number of MGFs was decreased subsequent to treatment with 50 µM or a higher concentration of H₂O₂. MGFs treated with H₂O₂ at 20 µM showed a similar cell growth curve as the one seen in 52-week-old mice. Phosphorylated p53 protein was increased in MGFs subsequent to treatment with 20 µM H2O2, along with an upregulated transcription of p21 and Mdm2 mRNAs. These results suggest that treatment with a lower concentration of H₂O₂ in MGFs induces cell cycle arrest, resulting in stress-induced premature senescence, possibly correlated with the development of periodontal diseases.

Expression and cellular localizaion of melatonin-synthesizing enzymes in rat and human salivary glands

Melatonin, discovered in 1958, is secreted by the pineal gland primarily during the night. Its secretion is controlled by the light/dark cycle of the environment. Melatonin is also produced in and secreted by various extrapineal organs, tissues and cells and its synthesizing enzyme arylalkylamine N-acetyltransferase (AANAT) is expressed in various extrapineal organs, tissues and cells. Recently, it was reported that melatonin is present in saliva, but it is not certain where melatonin was synthesized and whether it was secreted into saliva and what function it may have in saliva. The present study was performed to investigate where melatonin was synthesized and whether it was secreted by salivary glands into saliva. We performed immunohistochemical analysis of the expression of AANAT in rat parotid, submandibular and sublingual glands and the expression of both AANAT and hydroxyindole-O-methyltransferase (HIOMT) in human submandibular glands. We evaluated the expression of AANAT and HIOMT mRNA in rat submandibular glands by quantitative reverse transcription-polymerase chain reaction. As a result, we observed expression of AANAT in epithelial cells of striated ducts in rat salivary glands and expression of AANAT, HIOMT and melatonin in epithelial cells of striated ducts in human submandibular glands. In addition, we also confirmed the expression of the most potent melatonin receptor, melatonin 1a receptor, in rat buccal mucosa. Our findings suggest that melatonin might be produced and secreted by salivary glands directly into saliva and that it might play some physiological role in the oral cavity.

Salivary and gingival crevicular fluid melatonin in periodontal health and disease

BACKGROUND

Melatonin, with its antioxidant properties, plays a pertinent role in influencing the pathogenesis of periodontal disease. This study aims to detect the presence of melatonin in gingival crevicular fluid (GCF) and to assess the levels of salivary and GCF melatonin in periodontal disease and show the correlation between salivary and GCF melatonin.

METHODS

Forty-five subjects, based on the gingival and Russell periodontal indexes, were grouped as 15 healthy subjects (group 1), 15 subjects with gingivitis (group 2), and 15 subjects with periodontitis (group 3). Saliva and GCF samples were collected from all subjects. Melatonin levels were assessed using an enzyme-linked immunosorbent assay. The paired-sample test was used to correlate between saliva and GCF.

RESULTS

Melatonin was present in GCF (mean: 1.54 pg/ml) with significantly less concentration compared to that of saliva (mean: 2.17 pg/ml). Salivary and GCF melatonin levels were reduced to the lowest concentrations in patients with chronic periodontitis (salivary melatonin: 0.07 pg/ml; GCF melatonin: 0.06 pg/ml; P <0.05), which were inversely proportional to the clinical indices. There was no significant correlation between salivary and GCF melatonin levels (P >0.05).

CONCLUSIONS

Melatonin was expressed in GCF. Salivary and GCF melatonin levels varied from clinically healthy subjects (group 1) to subjects with periodontitis (group 3). Both salivary and GCF melatonin levels decreased in group 3 subjects compared to group 1 subjects, indicating that melatonin may have a protective role against periodontal disease, although further research is required to validate this hypothesis.

Melatonin expression in periodontal disease

BACKGROUND AND OBJECTIVE

It was the purpose of this study to examine the relationship between periodontal diseases and melatonin level.

MATERIAL AND METHODS

Forty-six patients with periodontal disease, together with 26 age- and gender-matched healthy controls, were included. Periodontal status was assessed using the Community Periodontal Index. Plasma and salivary melatonin levels were determined using specific commercial radioimmunoassays, whereas lymphocyte subpopulations (e.g. CD3, CD4, CD8, C19 and natural killer cells) were analyzed using flow cytometry.

RESULTS

Patients with periodontal disease had significantly (p < 0.001) lower plasma (9.46 +/- 3.18 pg/mL) and saliva (2.55 +/- 0.99 pg/mL) melatonin levels than healthy control patients (14.33 +/- 4.05 and 4.22 +/- 0.87 pg/mL, respectively). A biphasic relationship was observed between plasma melatonin levels and Community Periodontal Indices. The plasma melatonin level was reduced in patients with a lower Community Periodontal Index value (1 or 2) and increased in patients with a higher Community Periodontal Index value (3 or 4). Salivary melatonin parallels the changes of plasma melatonin. The higher the Community Periodontal Index, the older the patient and the higher the total lymphocyte counts. CD4 concentrations also increased as the disease worsened.

CONCLUSION

The results obtained from this study suggest that melatonin could act as a protective function in fighting periodontal infection. However, further studies in this area are encouraged.

N-acetylcysteine prevents LPS-induced pro-inflammatory cytokines and MMP2 production in gingival fibroblasts

Periodontitis is an inflammatory process that ultimately results in tooth loss. Although the primary etiologic agent for periodontitis is bacteria, the majority of periodontal tissue destruction is thought to be caused by an inappropriate host response. Reactive oxygen species (ROS) have been known to be involved in periodontal tissue destruction. We treated human gingival fibroblasts with lipopolysaccharide (LPS) obtained from E. coli and the periodontopathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, and examined their inflammatory responses in the presence and absence of the antioxidant N-acetylcysteine (NAC). LPS enhanced ROS production, as well as, expression of pro-inflammatory cytokines such as interleukin-1beta, interleukin-6, interleukin-8 and tumor necrosis factor-alpha, and the production and activation of MMP2. NAC suppressed all LPS-induced inflammatory responses examined, suggesting that LPS-induced ROS may play a major regulatory role in these responses in gingival fibroblasts. In addition, NAC prevented LPS-induced activation of p38 MAPK and JNK but not phosphorylation and subsequent degradation of IkB. These results indicate that NAC exerts anti-inflammatory effects in LPS-stimulated gingival fibroblasts, functioning at least in part via down-regulation of JNK and p38 MAPK activation. Furthermore, this work suggests that antioxidants may be useful in adjunctive therapies that complement conventional periodontal treatments.

Melatonin: potential functions in the oral cavity

BACKGROUND

Melatonin is synthesized and secreted by the pineal gland and other organs. The pattern of melatonin secretion is controlled by an endogenous circadian timing system and conveys information about the light-dark cycle to the organism, thereby organizing its seasonal and circadian rhythms. Melatonin has powerful antioxidant effects, functions in an immunomodulatory role, may protect against certain cancers, delays some age-related processes, stimulates the synthesis of type I collagen fibers, and promotes bone formation.

METHODS

An extensive review was made (e.g., using PubMed, Science Direct, and Web of Knowledge) of the literature.

RESULTS

Melatonin, which is released into the saliva, may have important implications for dental disorders, especially in periodontal disease. Diseases of the periodontium are known to be aggravated by free radicals and by alterations in the immune response to microorganisms that are present in plaque. In response to periodontal inflammation, the blood and salivary levels of melatonin may increase.

CONCLUSION

Melatonin may play a role in protecting the oral cavity from tissue damage that is due to oxidative stress, and it may contribute to the regeneration of alveolar bone through the stimulation of type I collagen fiber production and the modulation of osteoblastic and osteoclastic activity.

Localized Attachment Loss in Pendred Syndrome: Incidental?

BACKGROUND

Pendred syndrome is a rare, inherited, autosomal recessive disorder with an iodine organification defect of thyroxin produced by the thyroid gland. Its clinical features include sensorineural hearing loss, classically congenital and prelingual, and goiter.

METHODS

This is the first case report of Pendred syndrome in the dental literature with oral findings that include localized extensive attachment loss involving mandibular incisor teeth and idiopathic hypercementosis involving multiple teeth in addition to other oral manifestations, suggesting hypothyroidism-like macroglossia and macrocheilia. Furthermore, serum alkaline phosphatase along with inorganic calcium and phosphate levels were also elevated. Peripheral neutrophil function test suggested a defective function of neutrophils.

RESULTS

Management of the case included augmenting thyroxin supplementation, in consultation with an endocrinologist, and extraction of hopeless mandibular central incisors followed by placement of immediate transitional dentures.

CONCLUSION

A comprehensive medical history and systemic and laboratory evaluations should be considered a prerequisite to identify, manage, and report such rare conditions in routine clinical practice.

Hyperactivity and reactivity of peripheral blood neutrophils in chronic periodontitis

Some evidence exists that peripheral neutrophils from patients with chronic periodontitis generate higher levels of reactive oxygen species (ROS) after Fcgamma-receptor stimulation than those from healthy controls. We hypothesized that peripheral neutrophils in periodontitis also show both hyper-reactivity to plaque organisms and hyperactivity in terms of baseline, unstimulated generation and release of ROS. Peripheral neutrophils from chronic periodontitis patients and age/sex/smoking-matched healthy controls (18 pairs) were assayed for total ROS generation and extracellular ROS release, with and without stimulation (Fcgamma-receptor and Fusobacterium nucleatum), using luminol and isoluminol chemiluminescence. Assays were performed with and without priming with Escherichia coli lipopolysaccharide (LPS) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Phox gene expression (p22, p47, p67, gp91) was investigated using reverse transcription-polymerase chain reaction (RT-PCR). Neutrophils from patients produced higher mean levels of ROS in all assays. Total generation and extracellular release of ROS by patients' cells were significantly greater than those from controls after FcgammaR-stimulation, with (P = 0.023) and without (P < or = 0.023) priming with GM-CSF. Differences in unstimulated total ROS generation were not significant. By contrast, patients' cells demonstrated greater baseline, extracellular ROS release than those from controls (P = 0.004). This difference was maintained after priming with LPS (P = 0.028) but not GM-CSF (P = 0.217). Phox gene expression was similar in patient and control cells at baseline and stimulation with F. nucleatum (3 h) consistently reduced gp91(PHOX) transcripts. Our data demonstrate that peripheral neutrophils from periodontitis patients exhibit hyper-reactivity following stimulation (Fcgamma-receptor and F. nucleatum) and hyperactivity in terms of excess ROS release in the absence of exogenous stimulation. This hyperactive/-reactive neutrophil phenotype is not associated with elevated phox gene expression.

Local Application of Melatonin Into Alveolar Sockets of Beagle Dogs Reduces Tooth Removal–Induced Oxidative Stress

BACKGROUND

The antioxidant and anti-inflammatory hormone melatonin is secreted by saliva into the oral cavity, where it may protect the mucosal and gingival tissues from radical damage. To date, no studies have addressed the potential beneficial role of melatonin in the acute inflammatory response that follows oral surgical interventions, especially tooth extractions. The aim of this study was to determine whether tooth extraction induces changes in plasma oxidative stress levels, and whether melatonin treatment may counteract these changes.

METHODS

Maxillary and mandibular premolars and molars of 16 adult Beagle dogs were extracted under general anesthesia. Eight dogs were treated with 2 mg melatonin placed into the alveolar sockets, whereas the other eight dogs received only vehicle. Lipid peroxidation (LPO) and nitrite plus nitrate (NOx) levels were determined in plasma, whereas glutathione (GSH) and glutathione disulfide (GSSG) levels and glutathione peroxidase (GPx) and reductase (GRd) activities were measured in red blood cells before and 24 hours after tooth extraction.

RESULTS

Removal of the premolars and molars caused a significant rise in plasma LPO and NOx levels and in the erythrocyte GSSG/GSH ratio, whereas melatonin treatment restored the normal values of these parameters. Also, melatonin slightly increased erythrocyte GRd activity without changing GPx activity.

CONCLUSION

For the first time to our knowledge, the results show that during the immediate postoperative period following tooth extraction, there is a significant increase of oxidative stress, which is counteracted by the administration of melatonin into the alveolar sockets.

Total antioxidant capacity and superoxide dismutase activity levels in serum and gingival crevicular fluid in post-menopausal women with chronic periodontitis

OBJECTIVES

Menopause has been linked with oxidative stress and decreased antioxidant (AO) defence. A connection has been established between menopause and certain periodontal conditions. The objective of this study is to compare serum and gingival crevicular fluid (GCF) total antioxidant capacity (TAOC) and superoxide dismutase (SOD) concentrations in post-menopausal patients with chronic periodontitis (PMCP) with those of pre-menopausal chronic periodontitis patients (CP).

MATERIAL AND METHODS

Thirty-two PMCP patients, 31 CP patients, 25 post-menopausal periodontally healthy controls (PMPH) and 26 pre-menopausal controls (PH) were studied. After clinical measurements and samplings, serum and GCF TAOC and SOD concentrations were established in turn using an automated TAOC assay and spectrophotometric end point measurement. The results were analysed statistically.

RESULTS

Serum and GCF TAOC and SOD concentrations were significantly lower in menopause and periodontitis (p<0.05). The lowest values were in the PMCP group, whereas the highest values were in the PH group. While the effect of menopause was more evident in serum antioxidant analysis, the effect of periodontitis was observed to be more apparent in GCF.

CONCLUSIONS

A decrease in systemic and local AO defence was observed owing to both menopause and periodontitis. The lowest AO values in the PMCP group suggest that menopause may be a risk factor for periodontitis.

Reactive oxygen species and human inflammatory periodontal diseases

Reactive oxygen species (ROS) have emerged as important signaling molecules in the regulation of various cellular processes. They can be generated by the mitochondrial electron transport chain in mitochondria and activation of polymorphonuclear leukocytes (PMN) during inflammatory conditions. Excessive generation of ROS may result in attack of and damage to most intracellular and extracellular components in a living organism. Moreover, ROS can directly induce and/or regulate apoptotic and necrotic cell death. Periodontal pathologies are inflammatory and degenerative diseases. Several forms of periodontal diseases are associated with activated PMN. Damage of tissues in inflammatory periodontal pathologies can be mediated by ROS resulting from the physiological activity of PMN during the phagocytosis of periodontopathic bacteria.

Effects of Tempol, a membrane-permeable radical scavenger, in a rodent model periodontitis

BACKGROUND

Recent studies have demonstrated that Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a cell membrane-permeable radical scavenger, exerts protective effects in various models of inflammation and shock. Reactive oxygen species (ROS) plays a pivotal role in the induction of genes involved in physiological processes as well as in the response to inflammation.

AIM

We have investigated the effect of Tempol in a rat model of periodontitis.

MATERIALS AND METHODS

Periodontitis was induced in rats by placing a 2/0 braided silk ligature around the lower left first molar. At day 8, the gingivomucosal tissue encircling the mandibular first molar was removed for evaluation of neutrophils infiltration, tissue permeability, nitrotyrosine formation, poly-(ADP-ribose) polymerase (PARP) activation, radiography and histology.

RESULTS AND CONCLUSIONS

Legation significantly induced an increased neutrophil infiltration and a positive staining for nitrotyrosine formation and PARP activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone erosion as evaluated by radiography analysis. Intraperitonial injection of Tempol (10 mg/kg daily for 8 days) significantly decreased all of the parameters of inflammation as described above. This suggests that antioxidant therapies, which interfere with ROS, may be of benefit in the treatment of periodontitis.

Reduced development of experimental periodontitis by treatment with M40403, a superoxide dismutase mimetic

M40403, [manganese(II)dichloro[(4R,9R,14R,19R)-3,10,13,20,26 pentaazatetracyclo[20.3.1.0.(4,9)0(14,19)]hexacosa-1(26),-22(23),24-triene]], is a low-molecular-weight, synthetic, manganese-containing superoxide dismutase mimetic that removes superoxide anions without interfering with other reactive species known to be involved in inflammatory responses (e.g., nitric oxide, NO and peroxynitrite, ONOO-). As such, M40403 represents an important pharmacological tool to dissect the roles of superoxide anion in acute and chronic inflammation. For this purpose, the pharmacological profile of M40403 was evaluated in a rat model of periodontitis. Periodontitis was induced in rats by placing a 2/0 braided silk around the lower left first molar. On day 8 the gingivomucosal tissue encircling the first molar was removed for biochemical and histological analysis. Ligation significantly increased inducible nitric oxide synthase activity and expression, and gingival tissue revealed increased neutrophil infiltration, lipid peroxidation and positive staining for nitrotyrosine formation and poly (ADP-ribose) polymerase activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone destruction. Intraperitoneal injection of M40403 (10 mg/kg daily for 8 days) significantly decreased all of the above-described markers of inflammation. This suggests compounds that inhibit the generation of superoxide anion, such as M40403 may be potentially useful for the treatment of periodontitis.

Analysis of superoxide dismutase activity levels in gingiva and gingival crevicular fluid in patients with chronic periodontitis and periodontally healthy controls

OBJECTIVES

Superoxide dismutase (SOD) is an antioxidant enzyme that acts against superoxide, an oxygen radical, released in inflammatory pathways and causes connective tissue breakdown. In this study, SOD activities in gingiva and gingival crevicular fluid (GCF) from patients with chronic periodontitis (CP) and periodontally healthy controls were compared.

MATERIAL AND METHODS

Twenty-six CP patients and 18 controls were studied. In patients, teeth with moderate-to-severe periodontal breakdown and > or =5 mm pockets that required full-thickness flap surgery in the right or left maxillary quadrant, and in controls, teeth scheduled for extraction for orthodontic reasons were studied. After the clinical measurements (probing depth, clinical attachment level, gingival index, gingival bleeding index, plaque index), GCF samples were collected. Tissue samples were harvested from the same teeth, during flap operation in patients and immediately after tooth extraction in controls. SOD activities were spectrophotometrically assayed. The results were statistically analysed.

RESULTS

Gingival SOD activity was significantly higher in the CP group than in controls (p<0.05). No significant difference was found in GCF SOD activity between the groups (p>0.05). Correlations between gingival and GCF SOD activities were not statistically significant in CP and control groups (p>0.05).

CONCLUSION

In CP, SOD activity seems to increase in gingiva, probably as a result of a higher need for SOD activity and protection in gingiva in CP than in periodontal health, while not significantly changing in GCF, suggesting a weak SOD activity in GCF in periodontal disease state. The weak correlation between gingival and GCF SOD activities suggests distinct actions of these SODs.

Relationship between salivary melatonin levels and periodontal status in diabetic patients

Among other functions, melatonin exerts both antioxidative and immunoregulatory roles. The indoleamine is secreted in the saliva, although its role into the mouth is not known. Diabetic patients frequently display oral cavity pathologies such as periodontal disease (PD), an inflammatory disease coursing with an increase in free radical production. Thus, we compared the degree of PD and interleukin-2 (IL-2) levels with melatonin concentrations in plasma and saliva of diabetic patients. A total of 43 diabetic patients (20 with type I and 23 with type II diabetes) and 20 age- and sex-matched controls were studied. Dental and medical history of all patients was in accordance with the criteria of the WHO. The periodontal status was evaluated by the Community Periodontal Index (CPI). Plasma and salivary melatonin levels were determined by specific commercial radioimmunoassays, and plasma IL-2 was measured using a commercial enzyme-linked immunosorbent assay kit. Diabetic patients had plasma and saliva melatonin levels of 8.98 +/- 7.14 and 2.70 +/- 2.04 pg/mL, respectively. These values were significantly lower (P < 0.001) than those obtained in plasma and saliva of controls (14.91 +/- 4.75 and 4.35 +/- 0.98 pg/mL, respectively). Plasma and salivary melatonin concentrations show a biphasic response in diabetic patients. Melatonin decreased in patients with a CPI index of 2, and then increased reaching highest levels in patients with a CPI index of 4. By contrast, IL-2 levels decreased from CPI index 1 to 4. The results indicate that, in diabetic patients, the presence of a marked impairment of the oral status, as assessed by the CPI index, is accompanied by an increase in plasma and salivary melatonin. The increase in salivary melatonin excretion may have a periodontal protective role.

Fcgamma receptor polymorphisms in relation to periodontitis

OBJECTIVES

Evidence suggests functional relevance for polymorphisms in FcgammaR in relation to inflammatory and infectious diseases. The present aim was to investigate genetic polymorphisms in three FcgammaR in relation to susceptibility and severity of periodontitis.

MATERIAL AND METHODS

The study population consisted of 68 periodontitis patients and 61 controls (Northern European Caucasian background, mean ages 44 and 42 years, respectively). Among the patients, 12 subjects were diagnosed with aggressive periodontitis (AgP) and 56 individuals were diagnosed with chronic periodontitis (CP). Radiographic bone levels were scored for all teeth in the patients. Subjects were typed for the following genes (alleles): FcgammaRIIa (R131 or H131), FcgammaRIIIa (V158 or F158) and FcgammaRIIIb (NA1 or NA2).

RESULTS

Hardy-Weinberg equilibrium criteria were fulfilled for the different genotypes at the three genes investigated. The frequency of the FcgammaRIIIa-V158 allele in the patient population (53%) was higher than in the control group (39%) (OR 1.73 [1.06-2.85], p=0.034). The V158 carriage rate in AgP was even higher (63%). The frequency of the FcgammaRIIa-H131 allele in the total periodontitis population was 58%; for AgP this was 79%, compared with 51% in the control population (OR 3.68 [1.29-10.5], p=0.013). Also, the frequency of the FcgammaRIIa-H/H131 genotype was significantly higher in AgP patients than in controls (OR 9.07 [1.29-63.56], p=0.026, adjusted for smoking status and other potential confounders). Moreover, patients with the FcgammaRIIa-H/H131 genotype had more severe radiographic bone loss than patients with the other FcgammaRIIa genotypes.

CONCLUSION

The current study of relative small sample size suggests that the FcgammaRIIa-H/H131 genotype may be a putative susceptibility and severity factor, and the FcgammaRIIIa-V158 allele a putative susceptibility factor for periodontitis in Northern European Caucasians. These results need further verification and the biological importance of these findings needs further investigation.

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis

The antimicrobial activity of honokiol and magnolol, the main constituents of Magnolia officinalis was investigated. The antimicrobial activity was assayed by the agar dilution method using brain heart infusion medium and the minimum inhibitory concentration (MIC) were determined for each compound using a twofold serial dilution assay. The results showed that honokiol and magnolol have a marked antimicrobial effect (MIC = 25 microg/mL) against Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Micrococcus luteus and Bacillus subtilis, but did not show antimicrobial activity (MIC > or = 100 microg/mL) for Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. Our results indicate that honokiol and magnolol, although less potent than tetracycline, show a significant antimicrobial activity for periodontal pathogens. Hence we suggest that honokiol and magnolol might have the potential to be an adjunct in the treatment of periodontitis.

Antimicrobial activity of tannin components from Vaccinium vitis-idaea L

Reactive oxygen species have been implicated as important pathological mediators in many clinical disorders, including periodontal disease. As a possible alternative for the treatment of periodontal disease, the antimicrobial activity of six tannins isolated from Vaccinium vitis-idaea L., with confirmed antioxidant activity, were assayed by the agar dilution method against selected periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. The results showed that epicatechin-(4beta-->8)-epicatechin-(4beta-->8, 2beta-->O-->7)-catechin had strong antimicrobial activity against P. gingivalis and P. intermedia, but not A. actinomycetemcomitans. The other tannins tested did not show antimicrobial activity. We conclude that tannins isolated from V. vitis-idaea L. with antimicrobial activity could potentially be used for the treatment of periodontal disease.

Dietary vitamin C and the risk for periodontal disease

BACKGROUND

Vitamin C has long been a candidate for modulating periodontal disease. Studies of scorbutic gingivitis and the effects of vitamin C on extracellular matrix and immunologic and inflammatory responses provide a rationale for hypothesizing that vitamin C is a risk factor for periodontal disease.

METHODS

We evaluated the role of dietary vitamin C as a contributing risk factor for periodontal disease utilizing the Third National Health and Nutrition Examination Survey (NHANES III) which is representative of the U.S. civilian, non-institutionalized population.

RESULTS

A sample of 12,419 adults (20 to 90+ years of age), with dental measurements and assessment of dietary information as well as demographic and medical histories were included in the studies. Dietary vitamin C was estimated by a 24-hour dietary record. Individuals with periodontal disease were arbitrarily defined as those who had mean clinical attachment levels of > or =1.5 mm. Using multiple logistic regression analysis, we found a relationship between reduced dietary vitamin C and increased risk for periodontal disease for the overall population (odds ratio [OR] = 1.19; 95% CI: 1.05 to 1.33). Current and former tobacco users who were taking less dietary vitamin C showed an increased risk of periodontal disease with OR of 1.28, 95% CI: 1.04 to 1.59 for former smokers, and an OR of 1.21, 95% CI: 1.02 to 1.43 for current tobacco users. There was a dose-response relationship between the levels of dietary vitamin C and periodontal disease with an OR of 1.30 for those taking 0 to 29 mg of vitamin C per day, to 1.16 for those taking 100 to 179 mg of vitamin C per day as compared to those taking 180 mg or more of vitamin C per day.

CONCLUSION

Dietary intake of vitamin C showed a weak, but statistically significant, relationship to periodontal disease in current and former smokers as measured by clinical attachment. Those taking the lowest levels of vitamin C, and who also smoke, are likely to show the greatest clinical effect on the periodontal tissues.

Reactive oxygen species: a potential role in the pathogenesis of periodontal diseases

The pathological events leading to the destruction of the periodontium during inflammatory periodontal diseases are likely to represent complex interactions involving an imbalance in enzymic and non-enzymic degradative mechanisms. This paper aims to review the increasing body of evidence implicating reactive oxygen species (ROS), derived from many metabolic sources, in the pathogenesis of periodontal tissue destruction. ROS are generated predominantly by polymorphonuclear leukocytes (PMN) during an inflammatory response and are regarded as being highly destructive in nature. The detection of ROS oxidation products, the elevation of iron and copper ions, which catalyse the production of the most reactive radical species, and the identification of an imbalance in the oxidant/antioxidant activity within periodontal pockets, suggests a significant role for ROS in periodontal tissue destruction. In vitro studies have shown that ROS are capable of degrading a number of extracellular matrix components including proteoglycans, resulting in the modification of amino acid functional groups, leading to fragmentation of the core protein, whilst the constituent glycosaminoglycan chains undergo limited depolymerisation. The identification and characterisation of connective tissue metabolites in gingival crevicular fluid (GCF) resulting from the degradation of periodontal tissues, notably alveolar bone, provides further evidence for a role for ROS in tissue destruction associated with inflammatory periodontal diseases.

Oxidative injury and inflammatory periodontal diseases: the challenge of anti-oxidants to free radicals and reactive oxygen species

In recent years, there has been a tremendous expansion in medical and dental research concerned with free radicals, reactive oxygen species, and anti-oxidant defense mechanisms. This review is intended to provide a critical, up-to-date summary of the field, with particular emphasis on its implications for the application of "anti-oxidant therapy" in periodontal disease. We have reviewed the nomenclature, mechanisms of actions, features, and sources of most common free radicals and reactive oxygen species, as well as analyzed the typical biological targets for oxidative damage. Based on a review of direct and indirect anti-oxidant host defenses, particularly in relation to the key role of polymorphonuclear neutrophils in periodontitis, we review current evidence for oxidative damage in chronic inflammatory periodontal disease, and the possible therapeutic effects of anti-oxidants in treating and/or preventing such pathology, with special attention to vitamin E and Co-enzyme Q.

Antioxidant activity of tannin components from Vaccinium vitis-idaea L

Reactive oxygen molecules have been implicated as important pathological mediators in many clinical disorders and periodontal disease. To provide possible alternative treatment of periodontal disease, six tannins isolated from Vaccinium vitis-idaea L. were evaluated for anti-lipid peroxidation, anti-superoxide formation and free radical scavenging activity. The results showed that cinnamtannin B1 displayed the strongest anti-lipid peroxidation activity, proanthocyanidin A-1 displayed the strongest superoxide scavenging activity, and epicatechin-(4beta--> 6)-epicatechin-(4beta-->8, 2beta-->O--> 7)-catechin had the strongest anti-superoxide formation effect. We conclude that tannins isolated from V. vitis-idaea L. exhibited multiple antioxidant activity, and could be used for the treatment of periodontal disease.

Degradation of glycosaminoglycans by reactive oxygen species derived from stimulated polymorphonuclear leukocytes

The effect of reactive oxygen species (ROS), generated by in vitro stimulation of isolated PMN upon the main GAG components of mineralised and non-mineralised connective tissues was investigated. PMN were isolated from whole blood and the production of the ROS superoxide (O2.-) and hydroxyl radicals (.OH) was stimulated by the addition of phorbol myristyl acetate (PMA) and PMA/FeCl3-EDTA chelate respectively and their production assessed over a 24 h period. The glycosaminoglycans (GAG), hyaluronan, chondroitin 4-sulphate and dermatan sulphate, were exposed to the ROS fluxes, incubated at 37 degrees C for 1 h and 24 h. GAG fragmentation was examined by gel exclusion chromatography and modification to hexuronic acid and hexosamine residues determined. Stimulation of PMN with PMA resulted in a burst of O2.- production for 1 h, which was sustained at a reduced level for 24 h. Fragmentation of GAG was observed for all GAG examined. Modification to the GAG was evident, with hyaluronan being more susceptible to loss of GAG residues than sulphated GAG. Modification of sugar residues increased with the incubation time and loss of the hexuronic acid residues was greater than loss of hexosamine residues. Addition of FeCl3-EDTA chelate, which led to the generation of .OH and was sustained over the 24 h period, demonstrated similar trends of GAG modification although increased degradation and loss of hexosamine and hexuronic acid were observed. GAG chains are constituents of PGs and their modification is likely to affect the function of these macromolecules and be of importance in considering the pathogenesis of inflammatory diseases, including periodontal diseases.

Reactive oxygen species and antioxidants in inflammatory diseases

This paper aims to review the rôle of free radical-induced tissue damage and antioxidant defence mechanisms in inflammatory diseases that involve pathogenic processes similar to the periodontal diseases. There is a clearly defined and substantial role for free radicals or reactive oxygen species (ROS) in periodontitis, but little research has been performed in this area. This paper reviews the considerable data available relating ROS activity and antioxidant defence to inflammatory diseases and attempts to draw parallels with periodontitis, in an effort to stimulate more periodontal research in this important area. The recent discovery of the transcription factor nuclear factor kappa B (NF-kappa B) is reviewed and several potential pathways for cytokine-induced periodontal tissue damage, mediated by NF-kappa B1 are discussed. Emphasis is placed on cytokines that have been studied in periodontitis, principally TNF-alpha, IL-1, IL-6, IL-8 and beta-interferon. The link between cellular production of such important mediators of inflammation and the antioxidant (AO) thiols, cysteine and reduced glutathione (GSH), is discussed and it is hypothesised that NF-kappa B antagonists may offer important therapeutic benefits.

Active and alpha-1 proteinase inhibitor complexed leukocyte elastase levels in crevicular fluid from patients with periodontal diseases

Human leukocyte elastase is present in large amounts in the crevicular fluid of patients with periodontal disease and was considered as a putative biological marker of the evolution of such diseases. The aim of this work was to measure spectrophotometrically amounts of active elastase (AE) and elastase complexed to alpha 1 proteinase inhibitor (E-alpha 1-PI) in gingival crevicular fluid obtained, from patients suffering from rapidly progressive periodontitis (RPP group) or adult periodontitis (AP group) with different probing depths (3 to 5 mm and > 6 mm). AE and E-alpha 1-PI concentrations were negligible in healthy individuals. AE, but not E-alpha 1-PI, concentration appears to vary significantly with the probing depth in patients suffering either from rapidly progressive or adult periodontitis. No correlations were found between levels of AE and E-alpha 1-PI in the different groups of patients. AE concentration seems to be a marker of periodontal diseases in relation with probing depth.