Molecular analysis for bacterial contamination in dental unit water lines.

Bacterial contamination in dental unit waterlines (DUWLs) was evaluated by molecular techniques in addition to the conventional culture method. Water samples (n=8) from DUWLs were investigated for heterotrophic bacteria by culture method using R2A agar. The selected bacterial antibiotic-resistance genes and Legionella species-specific 16SrDNA were identified by PCR. The profiles of bacterial contamination in DUWLs were further identified by PCR-DGGE. In this study, no antibiotic-resistant or Legionella genes were detected. Polycyclic aromatic hydrocarbon-degrading bacterium, Novosphingobium sp. was the most prevalent in DUWLs. Conventional PCR and PCR-DGGE were shown to be potentially useful for monitoring of bacterial contamination in DUWLs.

Biological impacts of resveratrol, quercetin, and N-acetylcysteine on oxidative stress in human gingival fibroblasts.

In periodontitis, production of reactive oxygen species (ROS) by neutrophils induces oxidative stress and deteriorates surrounding tissues. Antioxidants reduce damage caused by ROS and are used to treat diseases involving oxidative stress. This study summarizes the different effects of resveratrol, quercetin, and N-acetylcysteine (NAC) on human gingival fibroblasts (HGFs) under oxidative stress induced by hydrogen peroxide. Real-time cytotoxicity analyses reveals that resveratrol and quercetin enhanced cell proliferation even under oxidative stress. Of the antioxidants tested, resveratrol is the most effective at inhibiting ROS production. HGFs incubated with resveratrol and quercetin up-regulate the transcription of type I collagen gene after 3 h, but only resveratrol sustained this up-regulation for 24 h. A measurement of the oxygen consumption rate (OCR, mitochondrial respiration) shows that resveratrol generates the highest maximal respiratory capacity, followed by quercetin and NAC. Simultaneous measurement of OCR and the extracellular acidification rate (non-mitochondrial respiration) reveals that resveratrol and quercetin induce an increase in mitochondrial respiration when compared with untreated cells. NAC treatment consumes less oxygen and enhances more non-mitochondrial respiration. In conclusion, resveratrol is the most effective antioxidant in terms of real-time cytotoxicity analysis, reduction of ROS production, and enhancement of type I collagen synthesis and mitochondrial respiration in HGFs.

Association of gingival recession and other factors with the presence of dentin hypersensitivity.

Dentin hypersensitivity (DH) may be present in association with gingival recession. The aim of this study was to determine quantitatively the association of gingival recession and other factors with the presence of DH. One hundred and four Japanese subjects with or without gingival recession were randomly selected. Intact canines and/or first premolars in both maxillary and mandibular quadrants were analyzed. Gingival recession was measured as a vertical length at the buccal site of the teeth. DH was recorded as an ordered categorical variable registering four increasing levels of pain after cold stimulation; from no discomfort to severe pain during and after stimulation (DH1, 2, 3, and 4). Association of DH with periodontal parameters and daily lifestyle was also investigated. Tooth-based analysis of 446 teeth from 104 subjects revealed that DH level was significantly higher in recessive teeth (1, 2, 3, and 4-8 mm) than in non-recessive teeth (0 mm). DH-positive rate in non-recessive teeth was only 18 % (DH1; 14 %, DH2; 3 %, and DH3; 1 %). Highest DH level was observed in teeth with severe recession (4-8 mm), showing DH0; 21 %, DH1; 33 %, DH2; 31 %, and DH3; 15 %. Recession-dependent increase in DH was observed, showing 18, 49, 52, 60, and 79 % DH-positive in teeth with 0, 1, 2, 3, and 4-8 mm recession, respectively. Plaque-free teeth showed a higher DH level than plaque-stained teeth, suggesting that good plaque control may be associated with the presence of DH. There were no significant differences in DH of teeth on the basis of smoking, probing depth, and bleeding on probing. Multiple logistic regression analysis revealed that gingival recession [odds ratio (OR) = 10.2, 95 % confidence interval (CI) = 5.5-18.9] and plaque deposition (OR = 0.3, 95 % CI = 0.2-0.5) were significant contributors to DH. Multilevel modeling analysis revealed that not only gingival recession and plaque deposition but also V-shaped cervical notch and tooth brushing frequency were associated with DH. These results demonstrate that the progression of gingival recession, plaque-free teeth, V-shaped cervical notch, and frequent brushing may be significant predictors of DH in canines and first premolars.

Stage of hepatocellular carcinoma is associated with periodontitis.

AIM: Periodontitis induces overproduction of reactive oxygen species (ROS). This state increases circulating ROS levels and may affect hepatocellular carcinoma (HCC). The Japan Integrated Stage (JIS) score is a novel staging system for HCC. The objective of the present study was to compare JIS scores in HCC patients with and without periodontitis. MATERIAL AND METHODS: We recruited 64 HCC patients comprising 31 chronic periodontitis subjects (HCC + P) and 33 periodontally healthy controls (HCC + H). Their JIS scores were recorded. Serum levels of reactive oxygen metabolites (ROM) from HCC + P, HCC + H and healthy age- and gender-matched subjects with healthy gingiva (control, n = 15) were also assessed for circulating ROS levels. RESULTS: The HCC + P and HCC + H groups had similar body mass index, habitual drinking and tobacco exposure data. The HCC + P group showed higher JIS scores than the HCC + H group (p = 0.027). Both the HCC + P and HCC + H groups had higher serum levels of ROM than controls (p < 0.001), while serum levels of ROM in the HCC + P group were a further 25.8% higher than those in the HCC + H group (p < 0.001). CONCLUSION: HCC patients with periodontitis had higher JIS score and circulating ROS level than HCC patients without periodontitis.

Hydrogen-rich water attenuates experimental periodontitis in a rat model.

AIM: Reactive oxygen species (ROS) contribute to the development of periodontitis. As molecular hydrogen can act as a scavenger of ROS, we examined the effects of treatment with hydrogen-rich water on a rat model of periodontitis. MATERIAL & METHODS: A ligature was placed around the maxillary molars for 4 weeks to induce periodontitis, and the animals were given drinking water with or without hydrogen-rich water. RESULTS: The rats with periodontitis which were treated with pure water showed a time-dependent increase in serum ROS level. Compared with the rats without periodontitis, the periodontitis-induced rats which were given pure water also showed polymorphonuclear leucocyte infiltration and alveolar bone loss at 4 weeks. Hydrogen-rich water intake inhibited an increase in serum ROS level and lowered expression of 8-hydroxydeoxyguanosine and nitrotyrosine in the periodontal tissue at 4 weeks. Such conditions prevented polymorphonuclear leucocyte infiltration and osteoclast differentiation following periodontitis progression. Furthermore, inflammatory signalling pathways, such as mitogen-activated protein kinases, were less activated in periodontal lesions from hydrogen-rich water-treated rats as compared with pure water-treated rats. CONCLUSION: Consuming hydrogen-rich water might be beneficial in suppressing periodontitis progression by decreasing gingival oxidative stress.

Periodontal treatment decreases plasma oxidized LDL level and oxidative stress.

Periodontitis induces excessive production of reactive oxygen species in periodontal lesions. This may impair circulating pro-oxidant/anti-oxidant balance and induce the oxidation of low-density lipoprotein (LDL) in blood. The purpose of this study was to monitor circulating oxidized LDL and oxidative stress in subjects with chronic periodontitis following non-surgical periodontal treatment. Plasma levels of oxidized LDL and oxidative stress in 22 otherwise healthy non-smokers with chronic periodontitis (mean age 44.0 years) were measured at baseline and at 1 and 2 months after non-surgical periodontal treatment. At baseline, chronic periodontitis patients had higher plasma levels of oxidized LDL and oxidative stress than healthy subjects (p < 0.001). Periodontal treatment was associated with a significant reduction in plasma levels of oxidized LDL (oxLDL)(p < 0.001) and oxidative stress (p < 0.001). At 2 months after periodontal treatment, the degree of change in the oxLDL was positively correlated with that in the oxidative stress (r = 0.593, p = 0.004). These observations indicate that periodontitis patients showed higher levels of circulating oxLDL and oxidative stress than healthy subjects. In addition, improved oral hygiene and non-surgical periodontal treatment were effective in decreasing oxLDL, which was positively associated with a reduction in circulating oxidative stress.

Effects of periodontitis on aortic insulin resistance in an obese rat model.

The combination of obesity and its associated risk factors, such as insulin resistance and inflammation, results in the development of atherosclerosis. However, the effects of periodontitis on atherosclerosis in an obese body remain unclear. The aim of the study was to investigate the effects of ligature-induced periodontitis in Zucker fatty rats on initiation of atherosclerosis by evaluating aortic insulin resistance. Zucker fatty rats (n=24) were divided into two groups. In the periodontitis group, periodontitis was ligature-induced for 4 weeks, whereas the control group was left unligated. After the 4-week experimental period, descending aorta was used for measuring the levels of lipid deposits, immunohistochemical analysis, and evaluation of gene expression. Levels of serum C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), and insulin were also measured. Rats in the periodontitis group had significantly enhanced lipid deposits in the aorta, but not in the control group. Expression of suppressor of cytokine signaling 3, vascular cell adhesion molecule 1, reactive oxygen species, nitrotyrosine, and endothelin-1 in the periodontitis group was more intense than that in the control group. Significantly decreased levels of phosphatidylinositol 3-kinase (Pi3k) catalytic beta-polypeptide (Pi3kcb), Pi3kp85, and insulin receptor substrate 1 and 2 were observed in the periodontitis group. Levels of serum CRP and TNF-alpha were significantly increased in the periodontitis group. Under insulin-stimulated conditions, aorta in the periodontitis group altered the Akt phosphorylation. Periodontitis in obesity induced the initial stage of atherosclerosis and disturbed aortic insulin signaling.

Short-term effects of non-surgical periodontal treatment on plasma level of reactive oxygen metabolites in patients with chronic periodontitis.

BACKGROUND: Elevated levels of blood reactive oxygen species (ROS) are associated with the severity of periodontitis. Therefore, improvement of periodontitis may result in a decrease in blood ROS. However, it is unclear how periodontal treatment affects blood ROS. Recently, reactive oxygen metabolites (ROMs) were recognized as a useful measure of blood ROS. The aim of this longitudinal study was to investigate the effect of non-surgical periodontal treatment on plasma ROMs in patients with chronic periodontitis. METHODS: Nineteen subjects with chronic periodontitis (mean age: 46.8 years) were monitored at baseline (prior to scaling and root planing) and 1 and 2 months after therapy. Dental health parameters were evaluated, and plasma was obtained at these time points from patients and controls (19 subjects without periodontitis; mean age: 45.3 years). The plasma ROM level was determined using a spectrophotometric technique. RESULTS: At baseline, patients with chronic periodontitis had higher plasma ROM level (441.8 +/- 71.1 Carratelli units) than the control subjects (324.4 +/- 34.0 Carratelli units; P <0.01). Probing depth, clinical attachment level, and bleeding on probing in patients with chronic periodontitis showed a significant improvement 2 months after non-surgical periodontal treatment, and this was accompanied by a significant reduction in plasma ROM level (P <0.01). CONCLUSIONS: In patients with chronic periodontitis, non-surgical periodontal treatment was effective at improving clinical parameters and reducing plasma ROMs. The improvement in chronic periodontitis by non-surgical periodontal treatment might offer clinical benefits by decreasing blood ROS.

Effects of obesity on gingival oxidative stress in a rat model.

BACKGROUND: Studies indicate a correlation between obesity and periodontitis. Oxidative stress is involved in the progression of periodontitis. The purpose of this study was to investigate the effects of obesity on gingival oxidative stress in a rat periodontitis model. METHODS: The obese Zucker rats (n = 14) and their lean littermates (n = 14) were each divided into two groups of seven rats. In one of each group, periodontitis was induced by ligature for 4 weeks, whereas the other group was left unligated. The level of 8-hydroxydeoxyguanosine and the ratio of reduced/oxidized glutathione were determined to examine gingival oxidative stress. The serum level of reactive oxygen metabolites and the gingival gene-expression pattern related to oxidative/metabolic stress, inflammation, and cell behavior were also evaluated. RESULTS: The obese rats weighed more than the lean rats at 4 weeks. Compared to lean rats, obese rats had enhanced gingival 8-hydroxydeoxyguanosine levels and a decreased ratio of reduced/oxidized glutathione in the gingival tissue, with increasing serum reactive oxygen metabolites. However, there were no significant differences in the degree of alveolar bone loss between lean and obese rats, except for teeth with and without ligatures in both rats. In addition, the periodontal lesion in obese rats showed higher 8-hydroxydeoxyguanosine levels and polymorphonuclear leukocyte infiltration than the inflamed ones in lean rats, with downregulation of multiple cytochrome P450 gene expression. CONCLUSIONS: Obesity induced gingival oxidative stress with increasing serum reactive oxygen metabolites in rats. In the periodontal lesion, gene expressions related to a capacity for xenobiotic detoxification were downregulated in the obese model.

Effects of improvement in periodontal inflammation by toothbrushing on serum lipopolysaccharide concentration and liver injury in rats.

OBJECTIVE: Periodontitis increases the serum lipopolysaccharide level, contributing to liver injury. Toothbrushing improves periodontitis and may also affect serum lipopolysaccharide concentration and periodontitis-induced liver injury. The purpose of the present study was to examine whether the improvement in periodontal inflammation by toothbrushing clinically affects the serum lipopolysaccharide level and hepatic pathological changes in rat periodontitis. MATERIAL AND METHODS: Thirty male Wistar rats were divided into 5 groups, 2 groups receiving topical application of pyrogen-free water to the gingival sulcus for 4 or 8 weeks. The next 2 groups received topical application of lipopolysaccharide and proteases for 4 or 8 weeks. The last group received topical application of lipopolysaccharide and proteases for 8 weeks, and the palatal gingiva was brushed with a powered toothbrush once a day for 4 weeks prior to the end of the experimental period. RESULTS: Topical application of lipopolysaccharide and proteases induced not only periodontal inflammation but also an elevation in the serum lipopolysaccharide concentration, with increasing hepatic inflammation, steatosis and 8-hydroxydeoxyguanosine levels in a time-dependent manner. The rats that received gingival stimulation showed decreased polymorphonuclear leukocyte infiltration and collagen loss levels in the periodontal lesions. Furthermore, this group also showed a decrease in serum lipopolysaccharide concentration and hepatic inflammation, steatosis and 8-hydroxydeoxyguanosine levels, compared with the group receiving no treatment. CONCLUSIONS: Toothbrushing promoted healing of periodontal lesions, decreased serum lipopolysaccharide concentration and suppressed liver injury in a rat periodontitis model.

A survey of Lasioderma serricorne (Fabricius) in Japanese Dental Clinics.

This study was to survey the capturing rate in Japanese dental clinics of the Lasioderma serricorne (cigarette beetles) , and to evaluate the beetle's potential as a carrier for transmission of nosocomial pathogens. L. serricorne imagoes were captured in pheromone traps in 14 Japanese dental clinics in August and September 2012 and 2013, and their numbers recorded. Polymerase chain reaction (PCR) for the bacterial antibiotic-resistant genes mecA, vanA, vanB, blaIMP, and blaVIM was performed on the captured L. serricorne imagoes. Bacterial species in the captured specimens were identified by 16S rRNA PCR and sequencing analysis. The L. serricorne imagoes were captured from 10 dental clinics (71.4%) . We failed to detect the presence of nosocomial antibiotic-resistant pathogens in L. serricorne imagoes. The bacterial species detected most commonly in the imagoes was Wolbachia sp., an intracellular proteobacterium infecting certain insect species. Monitoring of insects including L. serricorne should be incorporated into regiment of the infection control.

Relationship between periodontal condition and plasma reactive oxygen metabolites in patients in the maintenance phase of periodontal treatment.

BACKGROUND: The relationship between systemic antioxidative status and periodontal condition has been investigated in epidemiologic studies. However, little literature is available with regard to the correlation between systemic reactive oxygen species and periodontal condition. The purpose of this cross-sectional study was to investigate the relationship between plasma reactive oxygen metabolites (ROM) and periodontal condition in patients in the maintenance phase of periodontal treatment. METHODS: Eighty-one subjects (mean age: 57.4 years) who had entered a periodontal maintenance program were examined for probing depth (PD) and clinical attachment level (CAL). Plasma levels of ROM and biologic antioxidant potential (BAP) were determined with a free radical electric evaluator. RESULTS: The plasma level of ROM was positively correlated to mean CAL (r = 0.281; P = 0.011) and percentage of teeth with CAL > or =4 mm (r = 0.236; P = 0.034), but not mean PD (r = 0.196; P = 0.080). Logistic regression analysis showed that subjects with ROM levels >400 Carratelli units (CARR U) had significantly higher mean CAL compared to subjects with ROM < or =400 CARR U after adjusting for age, gender, and the number of teeth present (P = 0.011). However, the plasma level of BAP was not significantly correlated with the periodontal parameters. CONCLUSIONS: A positive association was found between plasma oxidative status and CAL in patients in the maintenance phase of periodontal therapy. A systemic increase in oxidative stress may influence the rate of progression of periodontal disease.

Mechanical stimulation of gingiva reduces plasma 8-OHdG level in rat periodontitis.

OBJECTIVE: Gingival cells respond to periodontal pathogens by generating reactive oxygen species, and such a condition would increase circulating oxidative stress. Improvement of gingival inflammation by toothbrushing may offer clinical benefits on not only periodontal health but also the circulatory conditions. We examined the effects of mechanical stimulation on the plasma 8-hydroxydeoxyguanosine level in a rat periodontitis model. DESIGN: In this experiment, male Wistar rats (n=18) were divided into three groups. The control group received topical application of pyrogen-free water to the gingival sulcus for 8 weeks, while the other two groups received topical application of bacterial pathogens (lipopolysaccharide and proteases). After 4 weeks, half of the rats in the experimental groups received daily mechanical stimulation with an electric toothbrush for 4 weeks. RESULTS: Rats treated with bacterial pathogens presented periodontal tissue damage and increased plasma levels of 8-hydroxydeoxyguanosine. Mechanical stimulation by toothbrushing decreased gingival inflammation and oxidative DNA damage indicated by a decrease in plasma 8-hydroxydeoxyguanosine. CONCLUSIONS: Mechanical stimulation of periodontally involved gingiva reduced 8-hydroxydeoxyguanosine in plasma and may contribute to a reduction in circulating oxidative stress associated molecules.

Oral administration of vitamin C prevents alveolar bone resorption induced by high dietary cholesterol in rats.

BACKGROUND: A high-cholesterol diet stimulates alveolar bone resorption, which may be induced via tissue oxidative damage. Vitamin C reduces tissue oxidative damage by neutralizing free radicals and scavenging hydroxyl radicals, and its antioxidant effect may offer the clinical benefit of preventing alveolar bone resorption in cases of hyperlipidemia. We examined whether vitamin C could suppress alveolar bone resorption in rats fed a high-cholesterol diet. METHODS: In this 12-week study, rats were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high-cholesterol diet supplemented with 0, 1, or 2 g/l vitamin C). Vitamin C was provided by adding it to the drinking water. The bone mineral density of the alveolar bone was analyzed by microcomputerized tomography. As an index of tissue oxidative damage, the 8-hydroxydeoxyguanosine level in the periodontal tissue was determined using a competitive enzyme-linked immunosorbent assay. RESULTS: Hyperlipidemia, induced by a high-cholesterol diet, decreased rat alveolar bone density and increased the number of tartrate-resistant acid phosphatase-positive osteoclasts. The expression of 8-hydroxydeoxyguanosine was upregulated in the periodontal tissues. Intake of vitamin C reduced the effect of a high-cholesterol diet on alveolar bone density and osteoclast differentiation and decreased periodontal 8-hydroxydeoxyguanosine expression. CONCLUSION: In the rat model, vitamin C suppressed alveolar bone resorption, induced by high dietary cholesterol, by decreasing the oxidative damage of periodontal tissue.

Chronic administration of lipopolysaccharide and proteases induces periodontal inflammation and hepatic steatosis in rats.

BACKGROUND: Epidemiologic studies suggest a relationship between periodontitis and liver diseases. A rat periodontitis model was used to investigate whether a causal relationship exists between periodontitis and liver diseases. METHODS: Fourteen male Wistar rats (8 weeks old) were divided into two groups: a periodontitis group in which Escherichia coli lipopolysaccharide (LPS) and Streptomyces griseus proteases were applied into the gingival sulcus for 8 weeks, and a control group using pyrogen-free water instead. After blood samples were collected, periodontal tissues and liver specimens were analyzed. RESULTS: Chronic administration of LPS and proteases to the gingival sulcus induced periodontitis and liver injury, including steatosis with inflammation and sinusoidal fibrosis. Apoptosis, enhanced concentration of 8-hydroxydeoxyguanosine, and activated production of tumor necrosis factor-alpha in liver were observed in the periodontitis group, with increased gingival inflammation, serum LPS, and reactive oxygen species. CONCLUSION: Periodontal inflammation in a rat model induced fatty liver disease through increased serum LPS.

Oxidative damage of periodontal tissue in the rat periodontitis model: effects of a high-cholesterol diet.

Studies suggest an association between consumption of a high-cholesterol diet and periodontitis. We addressed the mechanism by which high dietary cholesterol could be detrimental to periodontal health in a rat model. Feeding a high-cholesterol diet augmented the effects of bacterial pathogens and their products (e.g., lipopolysaccharide and proteases) on production of pro-inflammatory cytokines in fibroblasts. High dietary cholesterol also increased mitochondrial 8-hydroxydeoxyguanosine in the periodontal tissues. These results suggest that excessive tissue oxidative damage induced by high dietary cholesterol could potentiate pro-inflammatory cytokine production by fibroblasts stimulated with bacterial pathogens.

Hydrogen-Rich Water Intake Accelerates Oral Palatal Wound Healing via Activation of the Nrf2/Antioxidant Defense Pathways in a Rat Model.

The wound healing process attempts to restore the integrity and function of the injured tissue. Additionally, proinflammatory cytokines, growth factors, and oxidative stress play important roles in wound healing. The aim of this study was to determine whether hydrogen-rich water intake induces the activation of the Nrf2/antioxidant defense pathway in rat palatal tissue, thereby reducing systemic oxidative stress and proinflammatory cytokine levels and promoting healing-associated genes. A circular excisional wound was created in the oral palatal region, and the wound healing process was observed. The rats were divided into two experimental groups in which either hydrogen-rich water or distilled water was consumed. In the drinking hydrogen-rich water, the palatal wound healing process was accelerated compared to that in the control group. As molecular hydrogen upregulated the Nrf2 pathway, systemic oxidative stresses were decreased by the activation of antioxidant activity. Furthermore, hydrogen-rich water intake reduced proinflammatory cytokine levels and promoted the expression of healing-associated factors in rat palatal tissue. In conclusion, hydrogen-rich water intake exhibited multiple beneficial effects through activation of the Nrf2/antioxidant defense pathway. The results of this study support the hypothesis that oral administration of hydrogen-rich water benefits the wound healing process by decreasing oxidative stress and inflammatory responses.

Resveratrol improves oxidative stress and prevents the progression of periodontitis via the activation of the Sirt1/AMPK and the Nrf2/antioxidant defense pathways in a rat periodontitis model.

Oxidative stress is a key factor regulating the systemic pathophysiological effects associated with periodontitis. Resveratrol is a phytochemical with antioxidant and anti-inflammatory properties that can reduce oxidative stress and inflammation. We hypothesized that resveratrol may prevent the progression of periodontitis and reduce systemic oxidative stress through the activation of the sirtuin 1 (Sirt1)/AMP-activated protein kinase (AMPK) and the nuclear factor E2-related factor 2 (Nrf2)/antioxidant defense pathways. Three groups of male Wistar rats (periodontitis treated with melinjo resveratrol, periodontitis without resveratrol, and control rats with no periodontitis or resveratrol treatment) were examined. A ligature was placed around the maxillary molars for 3 weeks to induce periodontitis, and the rats were then given drinking water with or without melinjo resveratrol. In rats with periodontitis, ligature placement induced alveolar bone resorption, quantified using three-dimensional images taken by micro-CT, and increased proinflammatory cytokine levels in gingival tissue. Melinjo resveratrol intake relieved alveolar bone resorption and activated the Sirt1/AMPK and the Nrf2/antioxidant defense pathways in inflamed gingival tissues. Further, melinjo resveratrol improved the systemic levels of 8-hydroxydeoxyguanosine, dityrosine, nitric oxide metabolism, nitrotyrosine, and proinflammatory cytokines. We conclude that oral administration of melinjo resveratrol may prevent the progression of ligature-induced periodontitis and improve systemic oxidative and nitrosative stress.

Anti-ageing effects of dentifrices containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) on gingival collagen degradation in rats.

OBJECTIVE: Previous studies have demonstrated the relationship between ageing and oxidative stress. In this study, we examined the effects of topical application of a dentifrice containing anti-oxidative, anti-inflammatory, and anti-bacterial agents (Tomarina®) to the gingival surface on gingival collagen degradation in rats. DESIGN: Fischer 344 male rats (4 or 8 months old) were divided into two groups: experimental group and control group. Tomarina® (the experimental group) or control dentifrice (the control group) was applied 5 days per week for 2 months. RESULTS: In the control group, gingival collagen density decreased with ageing. In the experimental group, the collagen density did not change with ageing, and was greater than that in the control group at 10 months of age (p < 0.0083). In addition, the control group showed an increase in serum oxidative stress with ageing. The experimental group also showed increased serum oxidative stress, but the value was lower than the control group at 10 months of age (p < 0.0083). Furthermore, low expressions of protein oxidative damage in the periodontal tissue were observed in the experimental group, compared to the control group at 6 months and 10 months. CONCLUSION: These findings indicate that Tomarina® might suppress the effects of ageing on gingival collagen degradation, by decreasing oxidative stress in the rat model.

Longitudinal relationship between plasma reactive oxygen metabolites and periodontal condition in the maintenance phase of periodontal treatment.

AIM: The present cohort study describes the longitudinal relationship between plasma oxidative status and periodontitis progression during the maintenance phase of treatment. MATERIALS AND METHODS: Forty-five patients (mean age 58.8 years) were monitored from 2008 to 2013. Periodontal conditions, including probing pocket depth (PPD) and clinical attachment level (CAL), were recorded. Measurements of plasma reactive oxygen metabolites (ROM) and biologic antioxidant potential (BAP) were performed to evaluate plasma oxidative status. The patients were assigned into 2 groups as low and high plasma ROM level using a cut-off value which was median of plasma ROM level at baseline. RESULTS: In the subjects with low plasma ROM level at baseline, changes in mean CAL were positively correlated with changes in plasma ROM levels, bleeding on probing, and plaque control record, but not with PPD. In the subjects with high plasma ROM at baseline, changes in CAL were significantly associated with only PPD at baseline. On the other hands there were no significant associations between changes in CAL and those in plasma BAP levels. CONCLUSIONS: When plasma ROM level in periodontitis patients was low, increases in plasma ROM level were associated with those in CAL during the maintenance phase of treatment.