Role of free radicals and antioxidants in the pathogenesis of the inflammatory periodontal diseases

Gaseous ligand binding to Porphyromonas gingivalis HmuY hemophore-like protein in complex with heme

Porphyromonas gingivalis is the main pathogenic player in the development of periodontitis. To acquire heme, being an essential source of iron and protoporphyrin IX, P. gingivalis utilizes TonB-dependent outer membrane heme receptor (HmuR) and heme-binding hemophore-like protein (HmuY) as the main system for heme uptake from host hemoproteins. In this work, we present an extensive spectroscopic characterization of the binding of exogenous gaseous ligands to the holo-form of the HmuY (HmuY-heme) to unravel the mechanistic basis of heme release. Our data are consistent with a scenario where heme release from HmuY-heme is a multistep process that requires the initial rupture of one of the two heme‑iron coordination bonds with endogenous histidines.

Evaluation of thiol/disulfide homeostasis and ischemia modified albumin as potential markers for periodontitis

BACKGROUND

The current study aimed to assess the impact of periodontitis on oxidative stress parameters by examining serum total antioxidant capacity (TAS), total oxidant status (TOS), oxidative stress index (OSI), thiol/ disulfide homeostasis and ischemia modified albumin (IMA).

METHODS

The study had 90 participants, categorized into 3 groups: Group 1: Periodontally healthy; Group 2: Stage II Grade B periodontitis; Group 3: Stage III and IV Grade B periodontitis. Demographic and periodontal variables were assessed. The levels of serum TAS, TOS, OSI, IMA, and thiol/disulfide were assessed.

RESULTS

No significant differences in sex and age were detected among the groups (p > 0.05). When compared to Group 1, all clinical measurements were statistically significantly greater in Group 3 (p < 0.05). Statistical analysis revealed no significant differences in serum TAS, TOS, and OSI levels among the groups (p > 0.05). The highest serum IMA value was observed in Group 3 (p = 0.037), whereas native thiol (p = 0.00), total thiol (p = 0.00) and disulfide values (p = 0.023) were highest in Group 1.

CONCLUSIONS

These findings indicate that thiol/disulfide homeostasis and IMA could hold promise as a potential biomarker of inflammation in periodontitis.

Effects of ozone therapy as an adjuvant in the treatment of periodontitis: a systematic review and meta-analysis

BACKGROUND

Chronic periodontitis is an infectious disease initiated by plaque, which affects chewing and even general health. Ozone therapy, as a complementary means in the treatment of chronic periodontitis, numerous clinical trials have been conducted. We conducted this review to evaluate the effect of the ozone use accompanied by scaling and root planning (SRP) in periodontal treatment.

METHODS

Randomized controlled trials investigating the use of ozone therapy in chronic periodontitis. The search was carried out across PubMed, Cochrane Central Register of Controlled Trials, and EMBASE databases with the search period extending to July 2024. The quality of the identified studies was evaluated using the Cochrane Collaboration's Risk of Bias tool. The results were presented as weighted mean differences (WMD) with corresponding 95% confidence intervals (95% CI). Heterogeneity among the studies was assessed using the I2 test. Data analysis was performed using RevMan 5.4 and Stata 16.0.

RESULTS

Thirteen articles meeting the inclusion criteria. The meta-analysis revealed statistically significant differences in probing depth (PD) and gingival index (GI) reduction between ozone-assisted nonsurgical periodontal treatment and placebo-assisted treatment in patients with chronic periodontitis (P < 0.05). However, no significant differences were observed in clinical parameters such as bleeding on probing (BOP) percentage, plaque index (PI), and clinical attachment level (CAL) (P > 0.05).

CONCLUSION

Ozone therapy combined with SRP is superior to SRP alone in improving PD and GI indexes in patients with periodontitis, without increasing adverse reactions, and the effect is worthy of recognition. The research evidence indicates that ozone therapy in patients with chronic periodontitis has a positive effect.

Beneficial effects of cranberry juice enriched with omega-3 fatty acids in patients with type 2 diabetic and periodontal disease: A randomized pilot clinical trial

Background

The present study evaluated the effects of cranberry juice enriched with omega-3 on inflammatory, oxidative stress, and periodontal status in diabetic patients with periodontal disease.

Methods

Forty-one patients with diabetes (35‒67 years old) and periodontal disease were assigned to four groups: C: control (n=12), I1: omega-3 (n=10, 1 g), I2: cranberry juice (n=9, 200 mL), and I3: cranberry juice enriched with omega-3 (n=10, 200 mL, containing 1 g of omega-3) twice daily for 8 weeks. Serum and salivary total antioxidant capacity (TAC), malondialdehyde (MDA), serum uric acid, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), clinical attachment loss (CAL), pocket depth (PD), bleeding on probing (BOP), and plaque index were evaluated in all the subjects before and after the intervention.

Results

Serum and salivary TAC increased, and salivary MDA decreased in the I3 group compared with the control group. Additionally, serum MDA decreased in the I2 and I3 groups while serum TAC increased. Serum hs-CRP, IL-6, and TNF-α decreased in the I3 group compared with the baseline. Furthermore, serum hs-CRP and IL-6 decreased in the I3 group compared with the control group. After the intervention, PD and CAL significantly reduced in all the groups.

Conclusion

The consumption of cranberry juice enriched with omega-3 can be helpful as adjuvant therapy with non-surgical periodontal treatment in decreasing serum levels of IL-6 and hs-CRP, as well as serum and salivary levels of MDA while also increasing serum and salivary levels of TAC.

Clinical and Biochemical Effects of Antioxidant Gel as a Local Drug Delivery Agent in Stage II Grade A Periodontitis Patients: A Prospective Clinical Study

Background Periodontal tissue breakdown is mainly due to pathogenic bacteria and dysregulated immune response resulting in the production of reactive oxygen species/reactive nitrogen species (ROS/RNS) causing tissue degradation. Scaling and root planing (SRP) is usually done for the management of periodontitis. However, it has been reported that adjuncts like antibiotics, antiseptics, and antioxidants in the form of local drug delivery enhance the outcome of SRP. Aim The present clinical study aims to examine the efficacy of an antioxidant oral gel (Bluem®) as a local drug delivery agent adjunct to SRP in the management of stage II grade A periodontitis in terms of clinical and biochemical parameters. Materials and methods The prospective clinical study was conducted among 40 stage II grade A periodontitis patients. The participants were then divided into two groups: Group 1 (Control)-SRP alone (n=20) and Group 2 (Test)-antioxidant gel (Bluem®) with SRP (n=20). Clinical variables including plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment level (CAL) were recorded. Saliva (unstimulated) specimens were collected to measure total oxidant status (TOS), total antioxidant capacity (TAOC), and oxidative stress index (OSI). Specimen collection and assessment of clinical variables were done before intervention (baseline) and after three months. SPSS Software (Version 20.0, Armonk, NY, USA: IBM Corp) was used for statistical analysis. Intragroup and intergroup comparisons were done by paired t-test and independent t-test, respectively. A p-value <0.05 indicated that the result was statistically significant. Results On intragroup analysis, both the groups at three months revealed statistically significant improvement of PI, GI, PD, CAL, TOS, TAOC, and OSI (p<0.05) from baseline. Intergroup comparison in the third month showed a statistically significant improvement in favor of Group 2 in terms of all the clinical and biochemical parameters (p<0.05) except for PI (p>0.05). Conclusion The locally delivered antioxidant gel as an adjunct to SRP seems to be effective in reducing oxidative stress and improving the periodontal parameters among stage II grade A periodontitis patients.

Exploring enzyme inhibition and comprehensive mechanisms of antioxidant/prooxidative activity of natural furanocoumarin derivatives: A comparative kinetic DFT study

This study aimed to explore the antioxidant and prooxidative activity of two natural furanocoumarin derivatives, Bergaptol (4-Hydroxy-7H-furo [3,2-g] [1]benzopyran-7-one, BER) and Xanthotoxol (9-Hydroxy-7H-furo [3,2-g] [1]benzopyran-7-one, XAN). The collected thermodynamic and kinetic data demonstrate that both compounds possess substantial antiradical activity against HO• and CCl3OO• radicals in physiological conditions. BER exhibited better antiradical activity in comparison to XAN, which can be attributed to the enhanced deprotonation caused by the positioning of the -OH group on the psoralen ring. In contrast to highly reactive radical species, newly formed radical species BER• and XAN• exhibited negligible reactivity towards the chosen constitutive elements of macromolecules (fatty acids, amino acids, nucleobases). Furthermore, in the presence of O2•─, the ability to regenerate newly formed radicals BER• and XAN• was observed. Conversely, in physiological conditions in the presence of Cu(II) ions, both compounds exhibit prooxidative activity. Nevertheless, the prooxidative activity of both compounds is less prominent than their antioxidant activity. Furthermore, it has been demonstrated that anionic species can engage in the creation of a chelate complex, which restricts the reduction of metal ions when reducing agents are present (O2•─ and Asc─). Moreover, studies have demonstrated that these chelating complexes can be coupled with other radical species, hence enhancing their ability to inactivate radicals. Both compounds exhibited substantial inhibitory effects against enzymes involved in the direct or indirect generation of ROS: Xanthine Oxidase (XOD), Lipoxygenase (LOX), Myeloperoxidase (MPO), NADPH oxidase (NOX).

Role of Oxidative Stress in Periodontal Diseases

Periodontal disease, a significant worldwide health burden, is characterized by chronic inflammation and destruction of periodontal tissues, including the cementum, periodontal ligament (PDL), alveolar bone, and gingival tissue. Recent research has linked the development and progression of periodontal disease to oxidative stress. This study provides comprehensive explanations of the mechanisms behind oxidative stress in periodontal disease, with a focus on the generation of reactive oxygen species (ROS) and their effects on periodontal tissues. Oxidative stress triggers a number of detrimental reactions, including lipid peroxidation, protein oxidation, and damage to deoxyribonucleic acid (DNA). Alveolar bone resorption, connective tissue degradation, and periodontal inflammation are further conditions exacerbated by these processes. In addition, the delicate balance between antioxidants and oxidants is upset by oxidative stress, which impairs antioxidant defense systems and exacerbates periodontal tissue damage. This review highlights the negative effects of oxidative stress and enhances periodontal health outcomes.

The Role of Sulfhydryl (Thiols) Groups in Oral and Periodontal Diseases

AIM

The sulfhydryl (thiols) group of glutathione plays an important role in the neutralization of foreign organic compounds and the reduction in peroxides. The purpose of the study is to evaluate the concentration of sulfhydryl groups in the gingival tissue of healthy individuals and those with gingivitis or periodontitis, and to examine the differences between these groups.

MATERIAL AND METHODS

To assess the concentration of sulfhydryl groups (thiols) in the gingival tissue of healthy individuals and those with gingivitis or periodontitis, we used spectrophotometric analysis using dithionitrobenzoate (DTNB) as a reagent to measure the accessible sulfhydryl groups present in gingival tissue proteins. The sample was divided into three distinct groups: individuals with periodontal health, gingivitis, and periodontitis, and different indices were used to assess the periodontal status of the participants. Next, a statistical analysis was conducted to compare the concentrations of sulfhydryl groups among the different groups of patients.

CONCLUSIONS

The results of this study showed significantly decreased levels of sulfhydryl (thiols) groups in gingival tissue from patients with gingivitis and periodontitis, compared with healthy people (control group). These results confirm the role of sulfhydryl (thiols) groups in defense against free radicals. They share a significant role in detoxification, signal transduction, apoptosis, and various other functions at the molecular level.

Influence of Nutrition and Physical Activity on Local and Systemic Inflammatory Signs in Experimentally Induced Gingivitis

Although numerous studies have been published investigating the relationship between various dietary components and inflammatory periodontal disease, it has not yet been possible to clearly distinguish between periodontally healthy and unhealthy diets. This clinical study aimed to assess the association of specific food ingredients and physical activity on local and systemic inflammatory signs in experimentally induced gingivitis. Thirty-nine non-smoking periodontally healthy volunteers (mean age 23.2 ± 3.8 years) refrained from oral hygiene in the right maxilla for 21 days to induce an experimental gingivitis. Clinical examination (baseline and day 21) included plaque index, bleeding on probing (BOP), gingival crevicular fluid volume and high sensitive C-reactive protein levels (blood sample). Accompanying the intervention, volunteers documented with validated questionnaires their physical activity converted into metabolic equivalent (MET) and their nutrition converted into the dietary inflammatory index (DII). Significantly lower BOP (p = 0.039) was found for subjects with a more anti-inflammatory DII than for those with a more pro-inflammatory DII; higher MET values were correlated with lower BOP at day 21 (correlation coefficient -0.36). The results show an influence of nutrition and physical activity on periodontal inflammation signs. The DII may be a suitable parameter to verify the relationship between nutrition and inflammatory periodontal diseases.

Green Alternatives as Antimicrobial Agents in Mitigating Periodontal Diseases: A Narrative Review

Periodontal diseases and dental caries are the most common infectious oral diseases impacting oral health globally. Oral cavity health is crucial for enhancing life quality since it serves as the entranceway to general health. The oral microbiome and oral infectious diseases are strongly correlated. Gram-negative anaerobic bacteria have been associated with periodontal diseases. Due to the shortcomings of several antimicrobial medications frequently applied in dentistry, the lack of resources in developing countries, the prevalence of oral inflammatory conditions, and the rise in bacterial antibiotic resistance, there is a need for reliable, efficient, and affordable alternative solutions for the prevention and treatment of periodontal diseases. Several accessible chemical agents can alter the oral microbiota, although these substances also have unfavorable symptoms such as vomiting, diarrhea, and tooth discoloration. Natural phytochemicals generated from plants that have historically been used as medicines are categorized as prospective alternatives due to the ongoing quest for substitute products. This review concentrated on phytochemicals or herbal extracts that impact periodontal diseases by decreasing the formation of dental biofilms and plaques, preventing the proliferation of oral pathogens, and inhibiting bacterial adhesion to surfaces. Investigations examining the effectiveness and safety of plant-based medicines have also been presented, including those conducted over the past decade.

Targeting Nrf2 with Probiotics and Postbiotics in the Treatment of Periodontitis

Periodontitis is a destructive disease of the tooth-surrounding tissues. Infection is the etiological cause of the disease, but its extent and severity depend on the immune–inflammatory response of the host. Immune cells use reactive oxygen species to suppress infections, and there is homeostasis between oxidative and antioxidant mechanisms during periodontal health. During periodontitis, however, increased oxidative stress triggers tissue damage, either directly by activating apoptosis and DNA damage or indirectly by activating proteolytic cascades. Periodontal treatment aims to maintain an infection and inflammation-free zone and, in some cases, regenerate lost tissues. Although mechanical disruption of the oral biofilm is an indispensable part of periodontal treatment, adjunctive measures, such as antibiotics or anti-inflammatory medications, are also frequently used, especially in patients with suppressed immune responses. Recent studies have shown that probiotics activate antioxidant mechanisms and can suppress extensive oxidative stress via their ability to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The aim of this narrative review is to describe the essential role of Nrf2 in the maintenance of periodontal health and to propose possible mechanisms to restore the impaired Nrf2 response in periodontitis, with the aid of probiotic and postbiotics.

Salivary Antioxidant Capacity and Oral Health Status in Children with Visual Impairments—A Cross-Sectional Study

Background Children with visual impairment are at a higher risk for developing dental disease, and imbalances in the antioxidant levels may play an important role in the development and management of oral diseases.

Aim Our aim was to evaluate and compare the oral health status and salivary total antioxidant capacity (TAC) in children with and without visual impairment.

Methods Oral health was evaluated among 6 to 11 years old children with and without visual impairment (50 each) using World Health Organization oral health assessment form for caries prevalence, gingival health, and oral hygiene levels. Unstimulated saliva was collected and assayed for TAC using the phosphomolybdic method.

Statistical Analysis The data collected were tabulated, and the results, thus, obtained were subjected to statistical analysis using EZR software—version 1.37. The variables between the two groups were compared using the Mann–Whitney U test and Fisher's exact test. A correlation test was done using Spearman's correlation test.

Results The mean TAC levels among children with and without visual impairment were 49.17 (±25.702) and 156.67 (±56.031) µg/mL, respectively, which was statistically significant (p < 0.001). The children with visual impairment showed a significantly higher number of carious lesions compared with the control group (p < 0.001). Oral hygiene status and gingival health status were significantly poorer in children with visual impairments than the children in the control group (p < 0.001).

Conclusions Oral health was significantly poorer, and salivary TAC levels were significantly lower in children with visual impairment. There may be an inverse correlation between salivary TAC and oral health status. Clinical Significance: Since these children have been shown to have poorer oral health status, a baseline assessment of their salivary antioxidant capacity may indicate the need to reinforce oral care efforts and supplement them using an antioxidant-rich diet.

Evaluation of the effect of nonsurgical periodontal therapy on malondialdehyde and 8-hydroxy deoxyguanosine levels in chronic periodontitis

Background

Reactive oxygen species released on stimulation by periodontal pathogens cause oxidation of biomolecules and play significant role in periodontal disease pathogenesis.

Aim

This study aimed to evaluate the levels of oxidative by-products malondialdehyde (MDA) and 8-hydroxy deoxyguanosine (8-OHdG) as biomarkers in chronic periodontitis patients compared to healthy as well as before and after nonsurgical periodontal therapy. The correlation between biomarkers and clinical attachment level was also evaluated.

Settings and Design

A total of 112 subjects were included in this study. The subjects were divided into two groups (Group I included 56 healthy subjects and Group II constituted 56 chronic periodontitis patients) on the basis of clinical periodontal parameters.

Materials and Methods

Group I subjects received no treatment and were evaluated once only for clinical and oxidative stress biomarker parameters. Nonsurgical periodontal therapy was carried out in Group II patients and they were evaluated at baseline and 3 months after therapy.

Results

Both salivary and serum levels of MDA and 8-OHdG were found to be increased in chronic periodontitis patients as compared to healthy subjects. After nonsurgical periodontal therapy, the levels of MDA and 8-OHdG significantly reduced. Linear correlation between clinical attachment level and oxidative stress parameters was found to be positive and highly significant.

Conclusion

It can be concluded that periodontal therapy is effective in improving the oxidative stress condition.

A randomized, double-blind, split-mouth controlled clinical trial of systemically administered Lycopene on periodontal health

Background/Purpose

This research aimed to compare the effects of systemically prescribed Lycopene as a monotherapy and as an alternative to scaling and root planing in patients with chronic gingivitis.

Materials and methods

The participants were randomly assigned to one of two treatment groups: the experimental group (n = 50), which received 10 mg of Lycopene a day for two weeks, or the control group (n = 50) received a placebo for two weeks. For each category, quadrant distribution was randomized, with two quadrants receiving oral prophylaxis (OP) and two quadrants receiving no care (non-OP). At baseline, 1st, and 2nd weeks, the sulcus bleeding index, plaque index, gingival index, and salivary uric acid level were measured.

Results

All clinical criteria, including SBI, PI, GI, and salivary uric acid levels, showed a statistically significant decline in all patient types. Both clinical parameters were significantly reduced (p < 0.001) in the OP-lycopene group relative to the non-OP-placebo group and non-OP lycopene group (p < 0.05). The PI value in the OP-lycopene group was statistically significantly lower (p < 0.001) than in the non-OP-placebo group; there was no statistically significant difference in the other groups. Salivary uric acid levels in the OP- and non-OP- lycopene groups were significantly lower (p < 0.001) than in the non-OP-placebo population.

Conclusion

Based on the findings of this study, Lycopene seems to have a bright future as a treatment option for plaque-induced generalized chronic marginal gingivitis. More research with a broad sample size and multicentre trials is required.

Clinical relevance

The article reveals the positive relationship between Lycopene and gingivitis. The analysis shows that a combination of systemically administered Lycopene with oral prophylaxis can be a valuable tool in treating chronic gingivitis and controlling respiratory oxidative stress.

The Evaluation of Saliva Oxidative and Antioxidative Markers’ Levels in Adolescents with Gingival Inflammation

Periodontal disease is highly prevalent and affects 10%–15% of the world population. Salivary markers of oxidative stress and antioxidant status represent promising tool for research of oral diseases. Given the importance of reactive oxygen species (ROS) in the pathogenesis of periodontal disease, the aim of this study was to determine the association between oxidative stress parameters and periodontal disease gingivitis in adolescents. The study included a consecutive sample of 80 male and female participants referred to the Institute of Dentistry, Kragujevac, Serbia, as a result of periodontal problems or for routine control, aged 18 to 21, with definitive dentition as an inclusion criterion. Patients were divided into three groups depending on their gingival inflammation status. The first group was control group (n=20) with no gingival inflammation, the second group was with mild gingival inflammation (n=19), the third group was with moderate gingival inflammation (n=21) and the fourth group was with severe gingival inflammation (n=20). Oxidative stress parameters were measured in unstimulated whole saliva samples (superoxide anion radical, hydrogen peroxide, nitric oxide, index of lipid peroxidation, reduced gluthatione, catalase and superoxide dismutase). We have found increased levels of hydrogen peroxide and reduced glutathione in the saliva of patients with moderate levels of gingival inflammation, while the other markers were not significantly affected. In conclusion, oxidative stress plays a central role in the pathogenesis and the determination of oxidative and antioxidative levels could be a potent tool in controlling the development of gingivitis.

Has vitamin E any shreds of evidence in cisplatin-induced toxicity

Cisplatin is one of the highly consumed and effective antitumor agents whose clinical application is accompanied by nephrotoxicity adverse reaction. Also, other complications such as ototoxicity and hepatotoxicity are a matter of concern. Today, it is suggested that cisplatin-associated toxicities are mainly induced by free radicals production, which will result in oxidative organ injury. The evidence is growing over the protective effects of antioxidants on cisplatin-induced adverse reactions especially nephrotoxicity. The possible protective effects of vitamin E and its derivative in cisplatin-induced nephrotoxicity and ototoxicity are reviewed here at the light of pertinent results from basic and clinical research. Administration of vitamin E alone or in combination with other antioxidant agents could cause amelioration in oxidative stress biomarkers such as decreasing the level of malondialdehyde, reducing serum urea and creatinine, and also enhancing the activities of renal antioxidant enzymes including renal catalase, glutathione-S-transferase, and superoxide dismutase. Although the data from most of the studies are in favors of protective effects of vitamin E against cisplatin-induced toxicity, more clinical trials are needed to clarify the clinical importance of vitamin E administration as an antioxidant during cisplatin therapy in cancer condition.

Effect of micronutrient malnutrition on periodontal disease and periodontal therapy

Periodontitis is a complex chronic inflammatory noncommunicable disease, initiated by the development of a dysbiotic microbial plaque biofilm below the gingival margin. Whilst the pathogenic biofilm is a "necessary cause" of periodontitis, it is insufficient on its own to cause the disease, and a destructive immune-inflammatory response is a key to the translation of risk to destructive events. Other exposures or "component causes" include individual genetic predisposition, lifestyle (including smoking and nutrition), and environmental factors. Dietary nutrients are essential for life as they provide crucial energy sources in the form of macronutrients, as well as important cofactors in the form of micronutrients, which regulate the functionality of enzymes during the regulation of anabolic and catabolic processes in human cells. Moreover, micronutrients can regulate gene transcription factors, such as the proinflammatory nuclear factor kappa B and the anti-inflammatory nuclear factor (erythroid-derived 2)-like 2. This review focuses on the role of vitamins (vitamin A, carotenoids, the vitamin B complex, vitamins C, D, and E, and coenzyme Q10) and minerals (calcium, magnesium, iron, zinc, potassium, copper, manganese, and selenium) in human physiology and the impact of their deficiencies upon periodontal health and disease.

Evaluating clinical and laboratory effects of ozone in non-surgical periodontal treatment: a randomized controlled trial

OBJECTIVE

This study aims to evaluate the clinical and biochemical (oxidative stress and pro-inflammatory mediators) effects of the gaseous ozone use accompanied by scaling and root planning (SRP) in periodontal treatment.

MATERIAL AND METHODS

The study population consisted of 40 patients with chronic periodontitis (CP) randomly sorted into two groups of 20. The experimental group received SRP plus 3 watts gaseous ozone in two separate applications five days apart, whereas the control group received SRP plus placebo. Clinical periodontal parameters were assayed and saliva samples were taken before the initial and one month after the second treatment. Periodontal examination assessed plaque index (PI), gingival index (GI), probing depth, and clinical attachment level (CAL). Total antioxidant status (TAS), total oxidant status (TOS), nitric oxide (NO), 8-hydroxy-2'-deoxyguanosine (8-OHdG), myeloperoxidase (MPO), glutathione (GSH), malondialdehyde (MDA), and transforming growth factor-beta (TGF-β) levels were evaluated from saliva samples.

RESULTS

Changes following treatment in PI, GI, probing depth, and CAL scores were similar for both groups (p>0.05). Of note, TGF-β levels were observed to be higher in the treatment group than in controls (p<0.05). Changes in 8-OHdG, TAS, TOS, NO, MPO, GSH and MDA levels, however, were not significantly different between groups (p>0.05).

CONCLUSION

The findings of this study indicate that SRP plus gaseous ozone versus SRP alone does not correlate to a significant improvement in periodontal recovery.

Effects of blue-light irradiation during dental treatment

In dentistry, blue light is widely used for tooth bleaching and restoration procedures involving composite resin. In addition, many dentists use magnification loupes to enable them to provide more accurate dental treatment. Therefore, the use of light is indispensable in dental treatment. However, light can cause various toxicities, and thermal injuries caused by light irradiation are regarded as particularly important. In recent years, the eye damage and non-thermal injuries caused by blue light, the so-called "blue light hazard", have gained attention. Unfortunately, much of the research in this field has just begun, but our recent findings demonstrated that blue-light irradiation generates reactive oxygen species (ROS) and induces oxidative stress in oral tissue. However, they also showed that such oxidative stress is inhibited by antioxidants. There have not been any reports that suggested that the ROS-induced phototoxicity associated with blue-light irradiation causes direct clinical damage, but some disorders are caused by the accumulation of ROS. Therefore, it is presumed that it is necessary to suppress the accumulation of oxidative stressors in oral tissues during treatment. In the future, we have to promote discussion about the suppression of phototoxicity in dentistry, including concerning the use of antioxidants to protect against phototoxic damage.

The effect of periodontal therapy on oxidative stress biomarkers: A systematic review

AIM

To systematically review the literature about the effect of periodontal treatment on oxidative stress (OxS) biomarkers.

MATERIAL AND METHODS

Three databases (PubMed, EMBASE, and Scopus) were searched up to February 2018. Clinical trials with a follow-up of at least 6 weeks after mechanical periodontal treatment were included. Due to the high heterogeneity among the units and indices of measurements used in the studies, a meta-analysis was not performed.

RESULTS

Overall, 3,199 studies were retrieved, of which 20 were included. Four studies were randomized clinical trials (RCT), and 16 studies were non-RCTs. The most common OxS biomarkers used were 8-hydroxydeoxiguanosine (8-OHdG), total oxidant status (TOS), and total antioxidant status (TAS). After treatment, most of the studies reported a decrease in 8-OHdG concentration in the gingival crevicular fluid (GCF) and saliva. In addition, the salivary concentration of this biomarker was similar to periodontally healthy patients. Periodontal therapy was effective in reducing TOS in GCF, saliva, and serum in most studies. TAS, however, responded inconsistently to the periodontal intervention.

CONCLUSION

Periodontal therapy reduces the levels of OxS biomarkers, even to values similar to those found in periodontally healthy individuals. Additional RCTs are warranted, as the information is mainly based on nonrandomized studies.

Modulation of Neutrophil Extracellular Trap and Reactive Oxygen Species Release by Periodontal Bacteria

Oral bacteria are the main trigger for the development of periodontitis, and some species are known to modulate neutrophil function. This study aimed to explore the release of neutrophil extracellular traps (NETs), associated antimicrobial proteins, and reactive oxygen species (ROS) in response to periodontal bacteria, as well as the underlying pathways. Isolated peripheral blood neutrophils were stimulated with 19 periodontal bacteria. NET and ROS release, as well as the expression of NET-bound antimicrobial proteins, elastase, myeloperoxidase, and cathepsin G, in response to these species was measured using fluorescence-based assays. NET and ROS release was monitored after the addition of NADP (NADPH) oxidase pathway modulators and inhibitors of Toll-like receptors (TLRs). Moreover, bacterial entrapment by NETs was visualized microscopically, and bacterial killing was assessed by bacterial culture. Certain microorganisms, e.g., Veillonella parvula and Streptococcus gordonii, stimulated higher levels of ROS and NET release than others. NETs were found to entrap, but not kill, all periodontal bacteria tested. NADPH oxidase pathway modulators decreased ROS production but not NET production in response to the bacteria. Interestingly, TLR inhibitors did not impact ROS and NET release. These data suggest that the variability in the neutrophil response toward different bacteria may contribute to the pathogenesis of periodontal diseases by mechanisms such as bacterial avoidance of host responses and activation of neutrophils. Moreover, our results indicate that bacterium-stimulated NET release may arise in part via NADPH oxidase-independent mechanisms. The role of TLR signaling in bacterium-induced ROS and NET release needs to be further elucidated.

Effect of adjunctive use of systemic antioxidant therapy (N-acetylcysteine) on soluble receptor activator nuclear factor κB ligand levels in gingival crevicular fluid following surgical periodontal treatment for chronic periodontitis

N-acetylcysteine (NAC) is an anti-oxidant drug that has been used as a mucolytic agent and a paracetamol antidote for many years. This study was designed to determine the efficacy of the adjunctive use of NAC for periodontal treatment. Thirty subjects with moderate-to-severe chronic periodontitis were randomized to surgery with NAC (600 mg; S-NAC), surgery only (S-nonNAC), and healthy control groups. Gingival crevicular fluid (GCF) samples were obtained from all patients and sRANKL levels were determined by enzyme-linked immunosorbent assay at baseline, and 1, 3, and 7 months post-surgery. Plaque and gingival indices, probing depths, and clinical attachment levels were recorded at the same time. There was a significant reduction in probing depth at 3 months in the S-NAC group when compared to the S-nonNAC group (P < 0.05). However, no statistically significant differences in plaque and gingival indices, probing depths, clinical attachment levels, and sRANKL levels in GCF were noted between the surgical treatment groups at the end of 7 months. Hence, the use of adjunctive NAC resulted in a significant reduction in probing depths in the S-NAC group when compared to the S-nonNAC group at 3 months, but no statistically significant differences in GCF sRANKL levels were observed in the sites that underwent surgical treatment with or without NAC at different time intervals.

Effects of metformin on inflammation, oxidative stress, and bone loss in a rat model of periodontitis

Aim

To evaluate the effects of metformin (Met) on inflammation, oxidative stress, and bone loss in a rat model of ligature-induced periodontitis.

Materials & methods

Male albino Wistar rats were divided randomly into five groups of twenty-one rats each, and given the following treatments for 10 days: (1) no ligature + water, (2) ligature + water, (3) ligature + 50 mg/kg Met, (4) ligature + 100 mg/kg Met, and (5) ligature + 200 mg/kg Met. Water or Met was administered orally. Maxillae were fixed and scanned using Micro-computed Tomography (μCT) to quantitate linear and bone volume/tissue volume (BV/TV) volumetric bone loss. Histopathological characteristics were assessed through immunohistochemical staining for MMP-9, COX-2, the RANKL/RANK/OPG pathway, SOD-1, and GPx-1. Additionally, confocal microscopy was used to analyze osteocalcin fluorescence. UV-VIS analysis was used to examine the levels of malondialdehyde, glutathione, IL-1β and TNF-α from gingival tissues. Quantitative RT-PCR reaction was used to gene expression of AMPK, NF-κB (p65), and Hmgb1 from gingival tissues. Significance among groups were analysed using a one-way ANOVA. A p-value of p<0.05 indicated a significant difference.

Results

Treatment with 50 mg/kg Met significantly reduced concentrations of malondialdehyde, IL-1β, and TNF-α (p < 0.05). Additionally, weak staining was observed for COX-2, MMP-9, RANK, RANKL, SOD-1, and GPx-1 after 50 mg/kg Met. OPG and Osteocalcin showed strong staining in the same group. Radiographically, linear measurements showed a statistically significant reduction in bone loss after 50 mg/kg Met compared to the ligature and Met 200 mg/kg groups. The same pattern was observed volumetrically in BV/TV and decreased osteoclast number (p<0.05). RT-PCR showed increased AMPK expression and decreased expression of NF-κB (p65) and HMGB1 after 50 mg/kg Met.

Conclusions

Metformin, at a concentration of 50 mg/kg, decreases the inflammatory response, oxidative stress and bone loss in ligature-induced periodontitis in rats.

Metabolic control and periodontal treatment decreases elevated oxidative stress in the early phases of type 1 diabetes onset

OBJECTIVE

Recently, increasing concern has been focused on the contribution of oxidative stress in the pathology of periodontal disease and diabetes mellitus. Firstly, the present study aimed to analyze gingival crevicular fluid (GCF), salivary, and serum oxidative status in children with type 1 diabetes mellitus (T1DM) at diagnosis and systemically healthy children with and without gingivitis. Additionally, the diabetic patients were reevaluated after diabetes and periodontal treatment.

DESIGN

The study groups were composed of 32 T1DM patients at diagnosis, and age- and gender-matched thirty-six systemically healthy children with (G) and without (H) gingivitis. The diabetic patients who took insulin therapy (1.5 units/kg/day totally) and periodontal treatment (oral hygiene education with professional scaling) were reevaluated after 3 months. The levels of total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were recorded.

RESULTS

GCF, salivary, and serum OSI were elevated in group T1DM compared to the other groups at baseline (p<0.05), and decreased in group T1DM at reevaluation compared to baseline (p<0.05). GCF OSI was positively correlated with periodontal clinical parameters (p<0.05). Glycated hemoglobin was positively correlated with GCF TOS (r=0.302, p=0.007), GCF OSI (r=0.346, p=0.002), salivary TOS (r=0.326, p=0.046), and serum TOS (r=0.239, p=0.044).

CONCLUSION

The instability in the oxidative status that accompanies diabetes may be considered a significant pathogenic factor of diabetes-related periodontal inflammation.

Antioxidant enzymes in periodontitis

Periodontitis is basically an inflammatory disease initiated by the subgingival biofilm and modified by the individual's aberrant inflammatory/immune response. Various studies have pointed toward the role of oxidative stress in periodontitis. As the reactive oxygen species and antioxidants are in dynamic equilibrium, any disturbance in one would lead to changes in the other. As studying, individual antioxidants is a vast field, this review focuses on the role of antioxidant enzymes in periodontitis and in other related systemic conditions. It is highlighted that oxidative stress may be the missing link in these associations of periodontitis and other conditions. Also, the antioxidant enzymes may be considered a useful biomarker for periodontal diseases and antioxidant supplementation may be of help to reduce the burden of periodontal destruction without having much extra effort.

A Systematic Review on the Implication of Minerals in the Onset, Severity and Treatment of Periodontal Disease

Periodontal disease is an inflammatory disease with high prevalence in adults that leads to destruction of the teeth-supporting tissues. Periodontal therapy has been traditionally directed at reduction of the bacterial load to a level that encourages health-promoting bacteria and maintenance of oral-hygiene. The role of nutrition in different chronic inflammatory diseases has been the subject of an increasing body of research in the last decades. In this sense, there has been an important increase in the volume of research on role of nutrition in periodontitis since the diet has known effects on the immune system and inflammatory cascades. Minerals play a key role in all these processes due to the multiple pathways where they participate. To clarify the role of the different minerals in the establishment, progression and/or treatment of this pathology, a systemically review of published literature cited in PubMed until May 2016 was conducted, which included research on the relationship of these elements with the onset and progression of periodontal disease. Among all the minerals, calcium dietary intake seems important to maintain alveolar bone. Likewise, dietary proportions of minerals that may influence its metabolism also can be relevant. Lastly, some observations suggest that all those minerals with roles in immune and/or antioxidant systems should be considered in future research.

Role of nitro-oxidative stress in the pathogenesis of experimental rat periodontitis

Background and aims

Periodontitis is a common chronic adult condition that implicates oxidative damage to gingival tissue, periodontal ligament and alveolar bone. This study aimed at assessing the association between the nitro-oxidative stress and the periodontal tissues destructions in experimental rat periodontitis.

Methods

Periodontitis was induced in 15 male albino rats by repetitive lesions to the gingiva adjacent to the inferior incisors, performed daily, for 16 days. On D1, D3, D6, D8, and D16 the onset and evolution of periodontitis were monitored by clinical and histopathological examinations; blood was collected and serum nitro-oxidative stress was evaluated through total nitrites and nitrates, total oxidative status, total antioxidant capacity, and oxidative stress index.

Results

The results demonstrated that there was a graded and continuous increase in serum levels of total nitrites and nitrates, total oxidative status and oxidative stress index, which was consistent with the severity of periodontal destructions during periodontitis progression. However, total antioxidant capacity was not significantly influenced by the disease progression.

Conclusions

In experimental rat periodontitis, the systemic nitro-oxidative stress was associated with the severity of periodontal destructions assessed clinically and histopathologically. Therefore, systemic nitro-oxidative stress parameters might be used as diagnostic tools in periodontitis.

Eugenol and Its Role in Chronic Diseases

The active components in cloves are eugenol and isoeugenol. Eugenol has recently become a focus of interest because of its potential role in alleviating and preventing chronic diseases such as cancer, inflammatory reactions, and other conditions. The radical-scavenging and anti-inflammatory activities of eugenol have been shown to modulate chronic diseases in vitro and in vivo, but in humans, the therapeutic use of eugenol still remains to be explored. Based on a review of the recent literature, the antioxidant, anti-proliferative, and anti-inflammatory activities of eugenol and its related compounds are discussed in relation to experimentally determined antioxidant activity (stoichiometric factor n and inhibition rate constant) and theoretical parameters [phenolic O-H bond dissociation enthalpy (BDE), ionization potential (IP according to Koopman's theorem), and electrophilicity (ω)], calculated using a density functional theory method. Dimers of eugenol and its related compounds showed large antioxidant activities and high ω values and also exerted efficient anti-inflammatory activities. Eugenol appears to possess multiple antioxidant activities (dimerization, recycling, and chelating effect) in one molecule, thus having the potential to alleviate and prevent chronic diseases.

Nutrigenomics: the role of nutrients in gene expression

Improved understanding of the mechanism behind periodontal tissue destruction, the potential protective role of nutrients and the advent of modern genomic measurement tools has led to an increased interest in the association between nutrition and periodontal disease. To date, evidence for a direct link between periodontal disease and nutrition has come mainly from large observational cross-sectional studies or very small double-blind randomized supplementation trials, with a large proportion finding no significant association between the nutrient being analyzed and markers of periodontal disease status. The advent of the 'genomic era' has introduced the concept of nutrigenomic studies, which aim to reveal the relationship between nutrition and the genome to provide a scientific basis for improved public health through dietary means. Used alongside relatively inexpensive high-throughput technology, this will allow the effect of diet on the etiology of periodontal disease to be studied in greater detail. As it is extremely likely that interactions between genotype and diet are important in determining the risk of the most common complex diseases, it is highly probable that these interactions will be important in determining periodontal disease risk. Numerous nutritional genetic studies where the outcome measures have been markers of disease risk, most notably cardiovascular disease and cancer, provide proof of principle, highlight the importance of understanding these interactions and illustrate where the effect of dietary modification on periodontal disease progression may have been overlooked previously by observational studies.

Neutrophil Extracellular Traps in Periodontitis: A Web of Intrigue

Neutrophil extracellular traps (NETs) represent a novel paradigm in neutrophil-mediated immunity. NETs are believed to constitute a highly conserved antimicrobial strategy comprising decondensed nuclear DNA and associated histones that are extruded into the extracellular space. Associated with the web-like strands of DNA is an array of antimicrobial peptides (AMPs), which facilitate the extracellular destruction of microorganisms that become entrapped within the NETs. NETs can be released by cells that remain viable or following a unique form of programmed cell death known as NETosis, which is dependent on the production of reactive oxygen species (ROS) and the decondensing of the nuclear DNA catalyzed by peptidyl arginine deiminase-4. NETs are produced in response to a range of pathogens, including bacteria, viruses, fungi, and protozoa, as well as host-derived mediators. NET release is, however, not without cost, as the concomitant release of cytotoxic molecules can also cause host tissue damage. This is evidenced by a number of immune-mediated diseases, in which excess or dysfunctional NET production, bacterial NET evasion, and decreased NET removal are associated with disease pathogenesis. Periodontitis is the most prevalent infectious-inflammatory disease of humans, characterized by a dysregulated neutrophilic response to specific bacterial species within the subgingival plaque biofilm. Neutrophils are the predominant inflammatory cell involved in periodontitis and have previously been found to exhibit hyperactivity and hyperreactivity in terms of ROS production in chronic periodontitis patients. However, the contribution of ROS-dependent NET formation to periodontal health or disease remains unclear. In this focused review, we discuss the mechanisms, stimuli, and requirements for NET production; the ability of NET-DNA and NET-associated AMPs to entrap and kill pathogens; and the potential immunogenicity of NETs in disease. We also speculate on the potential role of NETs in the pathogenesis of periodontitis.

Role of Lycopene in Preventing Oral Diseases as a Nonsurgical Aid of Treatment

Without pigments, we are nothing. Life presents us with a kaleidoscope of colors. From the green grass of home to a forest's ruddy autumn hues, we are surrounded by living colors. Living things obtain their colors, with few exceptions, from natural pigments. In addition to their role in coloration, natural pigments carry out a variety of important biological functions. Of the various classes of pigments in nature, the carotenoids are among the most widespread and important ones, especially due to their varied functions. Lycopene is a red plant pigment found in tomatoes, apricots, guavas, watermelons, papayas, and pink grapefruits, with tomatoes being the largest contributor to the dietary intake of humans. Lycopene exhibits higher singlet oxygen quenching ability. Due to its strong color and nontoxicity, it is a useful food coloring agent. Moreover, it plays a multifunctional role as a nonsurgical aid in the treatment of oral diseases like leukoplakia, oral submucous fibrosis, lichen planus, oral squamous cell carcinoma, and also prevents the destruction of periodontal tissues. This review article focuses mainly on the role of lycopene in the prevention of various oral diseases.

Natural medicaments in dentistry

The major objective in root canal treatment is to disinfect the entire root canal system. Cleaning, shaping, and use of antimicrobial medicaments are effective in reducing the bacterial load to some extent, but some bacteria do remain behind and multiply, causing reinfection. Taking into consideration the ineffectiveness, potential side-effects and safety concerns of synthetic drugs, the herbal alternatives for endodontic usage might prove to be advantageous. Over the past decade, interest in drugs derived from medicinal plants has markedly increased. Phytomedicine has been used in dentistry as anti-inflammatory, antibiotic, analgesic, sedative and also as endodontic irrigant. Herbal preparations can be derived from the root, leaves, seeds, stem, and flowers. The PubMed database search revealed that the reference list for natural medicaments featured 1480 articles and in dentistry 173 articles. A forward search was undertaken on the selected articles and author names. This review focuses on various natural drugs and products as well as their therapeutic applications when used as phytomedicine in dentistry.

Role of vitamin e in prevention of oral cancer:-a review

Oral cancer is one of the major global threads to public health. The development of oral cancer is tobacco related mainly. Vitamin-E can inhibit reaction of the tobacco specific nitrosamine which undergoes specific activation, detoxification process. Dietary substitute such as vitamin-E can prevent oral cancer at a very early stage that is in premalignant lesions, in premalignant conditions. Main action of vitamin E includes increase immunity, controls free radicals mediated cell disturbances, maintains membrane integrity, inhibit cancer cell growth, cytotoxicity. Many past studies suggest the role of antioxidant (vitamin-E) in treatment of oral mucosal lesions particularly includes oral leukoplakia, oral lichen planus, oral submucous fibrosis and oral cancer. Vitamin-E as an antioxidant helps in prevention and slow the growth of Head and Neck cancer, improve the effects of cancer chemotherapy and reduce the side effects from both chemotherapy and radiation therapy for cancer patients. As prevention modality use of Vitamin-E may be beneficial for human beings.

Psidium guajava: A review on its potential as an adjunct in treating periodontal disease

Plants for thousands of years have been used to enhance health and for medicinal purposes. Psidium guajava is one which has an enormous wealth of medicinal value. It for long has been known for its anti-inflammatory, antimicrobial, antioxidant, antidiarrheal, antimutagenic properties. Despite of its widespread biologic uses there is a dearth of information on its therapeutic effect in the treatment of periodontal disease. Hence, this review is an attempt to highlight the potential of P. guajava in the treatment of periodontal disease. Internet databases PubMed, Google Scholar were searched and the most relevant articles were considered for review.

Reactive oxygen species in periodontitis

Recent epidemiological studies reveal that more than two-third of the world's population suffers from one of the chronic forms of periodontal disease. The primary etiological agent of this inflammatory disease is a polymicrobial complex, predominantly Gram negative anaerobic or facultative bacteria within the sub-gingival biofilm. These bacterial species initiate the production of various cytokines such as interleukin-8 and TNF-α, further causing an increase in number and activity of polymorphonucleocytes (PMN) along with these cytokines, PMNs also produce reactive oxygen species (ROS) superoxide via the respiratory burst mechanism as the part of the defence response to infection. ROS just like the interleukins have deleterious effects on tissue cells when produced in excess. To counter the harmful effects of ROS, human body has its own defence mechanisms to eliminate them as soon as they are formed. The aim of this review is to focus on the role of different free radicals, ROS, and antioxidants in the pathophysiology of periodontal tissue destruction.

Insights into and relative effect of chitosan-H, chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin on dentine bond strength

OBJECTIVE

The purpose of the study was to design and evaluate novel functional chitosan hydrogels (chitosan-H-propolis, chitosan-H-propolis-nystatin and chitosan-H-nystatin) by using the chitosan-H polymer as "dual function restorative materials".

MATERIALS AND METHODS

The nystatin/antioxidant carrier gel was prepared by dispersion of the corresponding component in glycerol and 3% acetic acid with 5% chitosan gelling agent was then added to the dispersion with continuous mixing. The natural bio-adhesive functionalized chitosan hydrogels were combined with built in drug delivery system and bio-actives such as propolis in order to increase the dentin bond strength capacity and maintain therapeutic properties of the alternative drug delivery system. The surface morphology, release behaviors (physiological pH and also in acidic conditions), stability of nystatin:antioxidant:chitosan and the effect of the hydrogels on the shear bond strength of dentin were also evaluated.

STATISTICAL ANALYSIS USED

Non-parametric ANOVA test was used to asses significance of higher shear bond values than dentine treated or not treated with phosphoric acid.

RESULTS

The release of both nystatin and propolis confer the added benefit of dual action of a functional therapeutic delivery when comparing the newly designed chitosan-based hydrogel restorative materials to commercially available nystatin alone. Neither the release of nystatin nor the antioxidant stability was affected by storage. Chitosan-H, chitosan-propolis, chitosan-nystatin and chitosan-nystatin-propolis treated dentine gives significantly (P < 0.05) higher shear bond values (P < 0.05) than dentine treated or not treated with phosphoric acid.

CONCLUSION

The added benefits of their unique functionality involve increased dentin adhesive bond strengths (after 24 h and after 6 months) and positive influence on the nystatin release. Nystatin was a model therapeutic agent, evaluating the concept of using functional materials as carriers for pro-drugs as well as displaying a certain degree of defence mechanism for free radical damage of the novel functional drug delivery. Overall, there was an insignificant relapse in the shear bond strength after 6 months.

Oxidative stress and cellular immunity in patients with recurrent aphthous ulcers

Recurrent aphthous ulcer (RAU) is an inflammatory condition of the oral mucosa characterized by painful, well-circumscribed, single or multiple round or ovoid ulcerations. The exact etiologic factor(s) of these ulcerations are not yet understood. The objective of this study was to evaluate inflammatory processes and free radical metabolism of 25 patients with RAUs compared to 25 healthy controls. The levels of malondialdehyde (MDA) and glutathione (GSH) were determined by high-performance liquid chromatography. Tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), IL-10, and IL-12 were determined by ELISA. Nitric oxide (NO), myeloperoxidase (MPO), total antioxidant status (TAS), and total oxidant status (TOS) levels were measured spectroscopically in serum. The levels of MDA, GSH, TNF-α, IL-2, IL-12, MPO, and TOS, and oxidative stress index (OSI) were higher, and the levels of NO, IL-10, and TAS were lower in patients with RAU than in controls. Statistical analysis showed that GSH, TNF-α, IL-2, IL-10, and OSI differed significantly in patients with RAU compared to controls. These parameters have important roles in oxidant/antioxidant defense.

Alteration of the redox state with reactive oxygen species for 5-fluorouracil-induced oral mucositis in hamsters

Oral mucositis is often induced in patients receiving cancer chemotherapy treatment. It has been reported that oral mucositis can reduce quality of life, as well as increasing the incidence of mortality. The participation of reactive oxygen species (ROS) in the pathogenesis of oral mucositis is well known, but no report has actually demonstrated the presence of ROS. Thus, the purpose of this study was thus to demonstrate the involvement of ROS and the alteration of the redox state in oral mucositis using an in vivo L-band electron spin resonance (ESR) technique. An oral mucositis animal model induced by treatment of 5-fluorouracil with 10% acetic acid in hamster cheek pouch was used. Lipid peroxidation was measured as the level of malondialdehyde determined by the thiobarbituric acid reaction. The rate constants of the signal decay of nitroxyl compounds using in vivo L-band ESR were calculated from the signal decay curves. Firstly, we established the oral mucositis animal model induced by treatment of 5-fluorouracil with acetic acid in hamster cheek pouch. An increased level of lipid peroxidation in oral mucositis was found by measuring malondialdehyde using isolated hamster cheek pouch ulcer. In addition, as a result of in vivo L-band ESR measurements using our model animals, the decay rate constants of carbamoyl-PROXYL, which is a reagent for detecting the redox balance in tissue, were decreased. These results suggest that a redox imbalance might occur by excessive generation of ROS at an early stage of oral mucositis and the consumption of large quantities of antioxidants including glutathione in the locality of oral mucositis. These findings support the presence of ROS involved in the pathogenesis of oral mucositis with anti-cancer therapy, and is useful for the development of novel therapies drugs for oral mucositis.

Protective role of the PG1036-PG1037-PG1038 operon in oxidative stress in Porphyromonas gingivalis W83

As an anaerobe, Porphyromonas gingivalis is significantly affected by the harsh inflammatory environment of the periodontal pocket during initial colonization and active periodontal disease. We reported previously that the repair of oxidative stress-induced DNA damage involving 8-oxo-7,8-dihydroguanine (8-oxoG) may occur by an undescribed mechanism in P. gingivalis. DNA affinity fractionation identified PG1037, a conserved hypothetical protein, among other proteins, that were bound to the 8-oxoG lesion. PG1037 is part of the uvrA-PG1037-pcrA operon in P. gingivalis which is known to be upregulated under H2O2 induced stress. A PCR-based linear transformation method was used to inactivate the uvrA and pcrA genes by allelic exchange mutagenesis. Several attempts to inactivate PG1037 were unsuccessful. Similar to the wild-type when plated on Brucella blood agar, the uvrA and pcrA-defective mutants were black-pigmented and beta-hemolytic. These isogenic mutants also had reduced gingipain activities and were more sensitive to H2O2 and UV irradiation compared to the parent strain. Additionally, glycosylase assays revealed that 8-oxoG repair activities were similar in both wild-type and mutant P. gingivalis strains. Several proteins, some of which are known to have oxidoreducatse activity, were shown to interact with PG1037. The purified recombinant PG1037 protein could protect DNA from H2O2-induced damage. Collectively, these findings suggest that the uvrA-PG1037-pcrA operon may play an important role in hydrogen peroxide stress-induced resistance in P. gingivalis.

Effect of low-dose doxycycline on serum oxidative status, gingival antioxidant levels, and alveolar bone loss in experimental periodontitis in rats

BACKGROUND

Subantibiotic doses of doxycycline (low-dose doxycycline [LDD]) have been widely used in periodontal treatment for enzymatic inhibition and related anti-inflammatory properties. The aim of the present study is to verify the possible effects of LDD on oxidative stress in relation to periodontal attachment loss associated with ligature-induced experimental periodontal disease in rats.

METHODS

Thirty female Wistar albino rats were divided into three study groups as follows: 1) control (C) rats; 2) rats with experimental periodontitis (PED); and 3) rats with PED that were treated with doxycycline (PED + LDD). PED was induced by placing ligatures around the cervix of the maxillary second molars for 21 days. The PED + LDD group was treated orally with doxycycline (6 mg/kg) for 21 days after the ligature was placed. After 21 days, the rats were euthanized, and samples of the right maxilla were defleshed and used for histologic and morphometric analyses. The gingival tissue of the left maxilla was used for the analysis of lipid peroxidation (malondialdehyde [MDA]) and antioxidant enzymes (catalase, glutathione peroxidase, and superoxide dismutase). Levels of serum total antioxidant status (TAS)/total oxidant status (TOS) and oxidative stress index (OSI) were also analyzed.

RESULTS

Alveolar bone loss was significantly higher in the PED group compared with the PED + LDD and C groups (P <0.05). Doxycycline exhibited the most prominent inhibition on gingival tissue levels of MDA and antioxidant enzymes (P <0.05). Doxycycline also significantly reduced TOS and OSI levels (P <0.05) but increased the TAS level.

CONCLUSION

Doxycycline helps to prevent periodontal tissue breakdown by inhibiting local and systemic oxidative stress.

Estimation of serum malondialdehyde in potentially malignant disorders and post-antioxidant treated patients: A biochemical study

BACKGROUND

Tobacco causes the generation of free radicals and reactive oxygen species (ROS) which are responsible for the high rate of lipid peroxidation. Malondialdehyde (MDA) is the most widely used agent to estimate the extent of lipid peroxidation. Timely diagnosis of the condition followed by supplementation with antioxidants like beta-carotene, pro-vitamin A, vitamin A, vitamin C, vitamin E, lipoic acid, zinc, selenium, and spirulina can prevent potentially malignant disorders.

MATERIALS AND METHODS

In this study, serum MDA was measured according to the method of Buege, in 15 normal samples and 15 patients who were histopathologically diagnosed with potentially malignant disordered and they were prescribed with antioxidants for a period of 4 week-time following which potentially malignant patients serum MDA was analyzed again to determine the extent of peroxidation reactions.

RESULTS

The mean serum MDA level in Group C1 was 0.7900 ± 0.2336 μM/L were as the mean serum MDA level of Group S1 was 2.478 ± 0.50756 μM/L and the values between them were highly significant. The values between C1 and S2 were found to be statistically significant. The mean serum MDA of S2 was 2.160 ± 0.41252 μM/L and the values were significant when compared to S1.

CONCLUSION

Serum MDA estimation in oral pre-cancer would serve in determining the extent of lipid peroxidation. Diagnosis of patients and administration of antioxidants has proven to be effective in declining the ROS and thus reducing the extent of damage on the cells. MDA may serve as a diagnostic tool in the estimation of oral pre-cancer and in evaluation of post-treated cases.

Immune modulatory and antioxidant effects of melatonin in experimental periodontitis in rats

Melatonin is an important antioxidant, and through its anti-inflammatory effects it can control immune responses, oxidative stress, and defense cell infiltration. Periodontitis is a disease of the oral cavity and the generation of free radicals is an important consideration in this disease. Therefore, we examined the immune-modulatory and antioxidant roles of melatonin in the treatment of periodontitis. In all, 30 male Wistar rats were randomly divided into three groups: the control group, the periodontitis-induced (PED) group, and the periodontitis+melatonin treatment (MEL+PED) group. The control group received no treatment, whereas periodontitis was induced in both the PED and the MEL+PED groups, with the MEL+PED group being treated with systemic melatonin. For the periodontitis-induced groups, the rats' mandibular first molar teeth were ligatured (3-0 cotton) in a submarginal position for 4 weeks, and then the ligature was removed. After removal of the ligature, melatonin was administered only to the MEL+PED group (an ip dose of 10mg/kg body wt for 15 days at 11:00 PM each day). In the histological examination, the MEL+PED group, which received the melatonin, showed reduced inflammatory cytokines (IL-1β, from 97.47 to 84.24pg/ml; TNF-α, from 0.22530 to 0.22519pg/ml), regulated oxidative stress parameters (MDA, from 41,458 to 30,708nmol/g; GSH, from 18,166 to 25,858nmol/mg), and less periodontal tissue destruction (CEJ-PL, lingual, from 244.54 to 140.57μm; buccal, from 235.6 to 158.93μm; and CEJ-BC, lingual, from 383.65 to 287.76μm; buccal, from 391.92 to 296.12μm). From these findings we conclude that, even when periodontitis was induced, melatonin reduced the oxidative damage in the rats' periodontal tissue by inhibiting the inflammatory effects and by restoring the antioxidants.

Antioxidant therapy as monotherapy or as an adjunct to treatment of periodontal diseases

BACKGROUND

Treatment of periodontal diseases by nonsurgical debridement has been considered as a gold standard procedure. Various other treatment modalities have been tried and tested to treat periodontal diseases. The aim of this study was to investigate the effect of antioxidant therapy on the progression of periodontal disease as monotherapy and/or as an adjunct to nonsurgical debridement.

MATERIALS AND METHODS

70 subjects were divided into three groups, i.e. clinically healthy, gingivitis and periodontitis group on the basis of Community Periodontal Index of Treatment Needs score. Gingivitis and periodontitis groups were further subdivided into three subgroups. At the baseline, periodontal attachment loss was recorded and scaling and root planing was performed in two subgroups. 6 mg antioxidant was administered in three divided doses for 2 weeks. Saliva samples were collected at baseline, 15(th) day, 30(th) day and 45(th) day for evaluation of uric acid levels.

RESULTS

Uric acid levels were significantly low in patients with more periodontal attachment loss as compared to clinically healthy and gingivitis groups. As the treatment was initiated, significant increase in uric acid levels was observed.

CONCLUSION

Rise in salivary antioxidant levels was observed on the administration of antioxidant therapy. Hence, antioxidant therapy can be used as an adjunct to the nonsurgical periodontal therapy.