Effects of smoking and treatment status on periodontal bacteria: evidence that smoking influences control of periodontal bacteria at the mucosal surface of the gingival crevice

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.

Effect of initial periodontal therapy on metallothionein levels in smokers and non-smokers with periodontitis

The aim of this study was to determine the effect of non-surgical periodontal therapy (NSPT) on mRNA expression of metallothionein (MT) and its levels in serum, saliva and gingival crevicular fluid (GCF) of smokers (S) and non-smokers (NS) with periodontitis (P).A total of 100 participants were included: 48 periodontally healthy (PH) subjects (24 S [PH + S] and 24 NS [PH + NS]) and 52 patients with P (27 S [P + S] and 25 NS [P + NS]). Clinical parameters were recorded, and biofluids (serum, saliva and GCF) and gingival tissue samples were obtained at baseline in all groups and 3 months after NSPT in P groups. MT levels in biofluids were determined by ELISA. In gingival tissues, MT-mRNA expression was quantified using real-time PCR. mRNA expression of MT and its levels in biofluids were significantly higher in P + S compared to other groups, and the differences between P + NS and PH + S were non-significant. A significant decrease was observed for MT levels in biofluids, and MT-mRNA expression in periodontitis patients after NSPT. In conclusion, smoking and periodontitis are associated with higher MT expression which decreases after NSPT. MT as an oxidative stress biomarker and its therapeutic role in periodontitis should be investigated in future studies.Clinical trial registration: The study was prospectively registered at Clinical Trials Registry-India (ctri.nic.in) as CTRI/2018/08/015427 on August 23, 2018.

Comparison Between the Conventional and Electronic Smoking Effects on Periodontal Health-A Cross-Sectional Study

Objectives

To compare the adverse effect of e-cigarettes and conventional cigarette smoking on periodontal health.

Materials and Methods

Sixty participants were split into two groups of 30 each (Group A-traditional cigarettes and Group B-e-cigarette smokers). Socio-demographic data, smoking, and oral health status were gathered using a self-administered questionnaire. Gingival index (GI), Russell's periodontal index, and clinical attachment loss (CAL) were recorded in patients of both the groups.

Results

The mean GI (1.79), periodontal index (5.92), and CAL (3.44) were higher in patients using traditional cigarettes than e-cigarettes. The questionnaire revealed that patients using traditional cigarettes had bleeding gums (32.22%), pus in the gums (39.22%), extracted teeth due to mobility (59.65%), discolored tooth (89.66%), and tongue (71.76%), which was more than e-cigarette smokers.

Conclusion

E-cigarette smokers have similar adverse effects on the periodontal tissues but are less as compared to normal cigarette smokers.

Clinical and microbiological effects of photodynamic therapy applied in non-surgical treatment of periodontitis

Background/Aim. Treatment of periodontitis undergoes several treatment phases. Non-surgical periodontal treatment (NSPT) represents the basic treatment stage, and it is applied to all the patients undergoing periodontal treatment. Adjunctive antimicrobial photodynamic therapy (aPDT) is one of several contemporary and relatively new possibilities with a role to inactivate microorganisms responsible for the occurrence and progression of the disease. The aim of this study was to comparatively analyze the clinical and microbiological effects of the NSPT alone, as well as combined with aPDT. Methods. A split-mouth method design was used in a prospective randomized controlled trial. The following clinical parameters were registered and monitored: plaque index (PI), bleeding on probing, probing depth (PD), and clinical attachment level (CAL). The presence of microorganisms Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola was detected by the polymerase chain reaction (PCR) method. Samples were tested before the therapy, as well as three months after the therapy. Therapeutic modalities of NSPT and NSPT with adjunct aPDT were examined. Results. All of the analyzed clinical parameters proved statistically significant improvement after the application of both treatment modalities (p < 0.001). Microbiological analyses showed that the total number of microorganisms was statistically significantly lower after the application of both methods (p < 0.001). Following the treatment, there was a statistically significantly reduced number of microorganisms Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola (p < 0.001). NSPT combined with aPDT led to a statistically significant improvement of both clinical parameters and microbiological status compared to NSPT applied on its own. Conclusion. The study showed improvement of all clinical indicators after the application of both treatment modalities. The total number of microorganisms was reduced as well as the number of specific microorganisms. Combining aPDT with NSPT led to a statistically significantly higher reduction in the number of microorganisms compared to NSPT alone.

The Impact of Smoking on Subgingival Plaque and the Development of Periodontitis: A Literature Review

Smoking seriously affects oral health and causes a variety of oral diseases. Numerous clinical data show that smoking significantly increases the risk of periodontitis, and the duration and amount of smoking are positively correlated with the severity of periodontitis. In fact, smoking creates an environment conducive to the colonization of periodontopathogens, which affects the process of periodontitis. Since subgingival plaque which harbors periodontopathogens is the initiation factor of periodontitis, it is critical to study the impact of smoking on subgingival microbiota for understanding the relationship between smoking and periodontitis. Continuous advances have been made on the understanding of effects of smoking on subgingival plaque and the development of periodontitis. Smoking is observed to enhance the pathogenicity of periodontopathogens, especially the red complex microorganisms, via promoting their colonization and infection, and regulating the expression and function of multiple virulence factors. Furthermore, smoking has a negative impact on periodontal microecological homeostasis, which is reflected in the decrease of commensal bacteria and the increase of periodontopathogens, as well as the changes in the interaction between periodontopathogens and their commensal microbes in subgingival biofilm, thus influencing the pathogenicity of the subgingival plaque. In summary, the mechanism of smoking on subgingival plaque microorganisms represented by the red complex and its effect on the periodontal microecology still need to be further explored. The relevant research results are of great significance for guiding the periodontal clinical treatment of smoking population. This review summarizes the effects and relevant mechanisms of smoking on subgingival plaque and the development of periodontitis.

Comparative Effects of E-Cigarette Aerosol on Periodontium of Periodontitis Patients

Introduction: Tobacco use is one of the main causes of periodontitis. E-cigarette are gaining in popularity, and studies are needed to better understand the impact of e-cigarettes on oral health. Objective: To perform a longitudinal study to evaluate the adverse effects of e-cigarettes on periodontal health. Methods: Naïve E-cigarette users, cigarette smokers, and non-smokers were recruited using newspaper and social media. Age, gender, and ethnicity, were recorded. Participants were scheduled for two visits 6 months apart. At each visit, we collected data on the frequency and magnitude of e-cigarette and cigarette use, and alcohol consumption. Carbon monoxide (CO) levels, cotinine levels, salivary flow rate, periodontal probing depth (PD), bleeding on probing (BoP), and clinical attachment loss (CAL) were also determined at both baseline and follow-up visits and compared between groups with two-way repeated measures ANOVA. Periodontal diagnosis and other categorical variables were compared between groups with the chi-square statistic and logistic regression. Results: We screened 159 subjects and recruited 119 subjects. One-hundred-one subjects (31 cigarette smokers, 32 e-cigarette smokers, and 38 non-smokers) completed every assessment in both visits. The retention and compliance rate of subjects was 84.9%. The use of social media and craigslist was significant in recruiting e-cigarette subjects. Ethnicity and race differed between groups, as did average age in the male subjects. Carbon monoxide and salivary cotinine levels were highest among cigarette smokers. Bleeding on probing and average PDs similarly increased over time in all three groups, but CAL uniquely increased in e-cigarette smokers. Rates of severe periodontal disease were higher in cigarette smokers and e-cigarette users than non-smokers, but interpretation is confounded by the older age of the cigarette smokers. Conclusion: Among the recruited participants, CAL after 6 months was significantly worse only in the e-cigarette smokers. This study design and protocol will assist in future larger studies on e-cigarette and oral health.

Porphyromonas gingivalis, the most influential pathogen in red-complex bacteria: A cross-sectional study on the relationship between bacterial count and clinical periodontal status in Japan

BACKGROUND

Porphyromonas gingivalis is a key pathogen in microbiota associated with periodontitis. The purpose of the present study was to assess the association between salivary counts of red-complex bacteria and clinical periodontal status in a Japanese population.

METHODS

A total of 977 subjects who visited a general dental clinic in Japan from 2003 to 2006 were enrolled in the study. Stimulated saliva was obtained, and the amounts of major periodontal bacteria were measured using real-time polymerase chain reaction. Probing pocket depth (PPD), bleeding on probing (BOP), and each subject's average proximal bone crest level (BCL) on dental radiographs were measured.

RESULTS

The number of P. gingivalis strongly associated with percentage of 4 mm or more PPD sites, BOP positive percentage, and 1.5 mm or more BCL sites. The detection of P. gingivalis with Treponema denticola and/or Tannerella forsythia showed a high rate of three positive clinical parameters, whereas the only P. gingivalis detected group and those without P. gingivalis had a low rate of three positive clinical parameters.

CONCLUSION

Among red-complex bacteria, the amount of P. gingivalis showed the strongest association with the severity of periodontal condition, and co-occurrence of P. gingivalis with T. denticola and/or T. forsythia showed heightened progression of periodontitis.

Oral Candida carriage in smokers and tobacco users: A systematic review and meta-analysis of observational studies

OBJECTIVE

To synthesize evidence from observational studies that evaluated the association between smoking and smokeless tobacco with oral Candida carriage.

METHODS

Following the PRISMA guidelines, we searched through PubMed/MEDLINE, Web of Science, Embase, and Scopus without restrictions until April 2020 for studies that assessed this association. Following study retrieval and selection, relevant data were extracted, and the risk of bias was assessed by two independent authors using the Newcastle-Ottawa Scale. A fixed-effect meta-analysis was performed due to insignificant heterogeneity between studies.

RESULTS

We identified 14 studies that were eligible for inclusion in this review. The pooled odds ratio (OR; six studies) for Candida carriage among smokers and non-smokers was 2.15 (95% confidence interval [CI]: 1.47, 3.14; I2 = 8%; P < 0.0001). The OR (five studies) for Candida carriage among smokeless tobacco users and non-users was 1.77 (95% CI: 1.29, 2.44; I2 = 46%; P = 0.0004).

CONCLUSION

Our findings suggest a significant relationship between smoking/smokeless tobacco users and oral Candida carriage. However, observational studies cannot clarify whether the observed epidemiologic association is a causal effect or the result of some unmeasured confounding variables. Therefore, continued efforts to measure the association between smoking and oral Candida carriage are required.

Electronic Cigarette Aerosol Modulates the Oral Microbiome and Increases Risk of Infection

The trend of e-cigarette use among teens is ever increasing. Here we show the dysbiotic oral microbial ecology in e-cigarette users influencing the local host immune environment compared with non-smoker controls and cigarette smokers. Using 16S rRNA high-throughput sequencing, we evaluated 119 human participants, 40 in each of the three cohorts, and found significantly altered beta-diversity in e-cigarette users (p = 0.006) when compared with never smokers or tobacco cigarette smokers. The abundance of Porphyromonas and Veillonella (p = 0.008) was higher among vapers. Interleukin (IL)-6 and IL-1β were highly elevated in e-cigarette users when compared with non-users. Epithelial cell-exposed e-cigarette aerosols were more susceptible for infection. In vitro infection model of premalignant Leuk-1 and malignant cell lines exposed to e-cigarette aerosol and challenged by Porphyromonas gingivalis and Fusobacterium nucleatum resulted in elevated inflammatory response. Our findings for the first time demonstrate that e-cigarette users are more prone to infection.

The Impact of Smoking on Subgingival Microflora: From Periodontal Health to Disease

Periodontal disease is one of the most common diseases of the oral cavity affecting up to 90% of the worldwide population. Smoking has been identified as a major risk factor in the development and progression of periodontal disease. It is essential to assess the influence of smoking on subgingival microflora that is the principal etiological factor of the disease to clarify the contribution of smoking to periodontal disease. Therefore, this article reviews the current research findings regarding the impact of smoking on subgingival microflora and discusses several potential mechanisms. Cultivation-based and targeted molecular approaches yield controversial results in determining the presence or absence of smoking-induced differences in the prevalence or levels of certain periodontal pathogens, such as the “red complex.” However, substantial changes in the subgingival microflora of smokers, regardless of their periodontal condition (clinical health, gingivitis, or periodontitis), have been demonstrated in recent microbiome studies. Available literature suggests that smoking facilitates early acquisition and colonization of periodontal pathogens, resulting in an “at-risk-for-harm” subgingival microbial community in the healthy periodontium. In periodontal diseases, the subgingival microflora in smokers is characterized by a pathogen-enriched community with lower resilience compared to that in non-smokers, which increases the difficulty of treatment. Biological changes in key pathogens, such as Porphyromonas gingivalis, together with the ineffective host immune response for clearance, might contribute to alterations in the subgingival microflora in smokers. Nonetheless, further studies are necessary to provide solid evidence for the underlying mechanisms.

Porphyromonas gingivalis genes conferring fitness in a tobacco-rich environment

Smokers are more likely than non-smokers to harbour Porphyromonas gingivalis, they are more susceptible to destructive periodontal disease and smokers may, ultimately, benefit from tobacco-specific preventive and treatment strategies. A Mariner transposon insertion library for P. gingivalis ATCC 33277 was exploited to define 256 genes as essential for P. gingivalis survival in a tobacco-rich environment. Genes whose products play roles in protein transport and catabolism, nicotinamide processing, protection against oxidative stress, drug resistance, and transcriptional regulation have all been identified as essential for CSE survival. Many of these tobacco-essential genes are also requisite for epithelial colonization and abscess formation, suggestive of a core stress-related P. gingivalis genome. Single-gene deletions in several of the TnSeq-implicated genes led to significantly reduced P. gingivalis fitness upon competition with the parent strain, under conditions of cigarette smoke extract-induced stress (1,000 ng/ml nicotine equivalents). This study identifies, for the first time, a subset of P. gingivalis genes required for surviving the plethora of insults present in cigarette smoke. Such conditionally essential genes may delineate bacterial persistence strategies and represent novel therapeutic foci for the prevention of P. gingivalis infection and related diseases in smokers and in general.

Tobacco exposure associated with oral microbiota oxygen utilization in the New York City Health and Nutrition Examination Study

PURPOSE

The effect of tobacco exposure on the oral microbiome has not been established.

METHODS

We performed amplicon sequencing of the 16S ribosomal RNA gene V4 variable region to estimate bacterial community characteristics in 259 oral rinse samples, selected based on self-reported smoking and serum cotinine levels, from the 2013-2014 New York City Health and Nutrition Examination Study. We identified differentially abundant operational taxonomic units (OTUs) by primary and secondhand tobacco exposure, and used "microbe set enrichment analysis" to assess shifts in microbial oxygen utilization.

RESULTS

Cigarette smoking was associated with depletion of aerobic OTUs (Enrichment Score test statistic ES = -0.75, P = .002) with a minority (29%) of aerobic OTUs enriched in current smokers compared with never smokers. Consistent shifts in the microbiota were observed for current cigarette smokers as for nonsmokers with secondhand exposure as measured by serum cotinine levels. Differential abundance findings were similar in crude and adjusted analyses.

CONCLUSIONS

Results support a plausible link between tobacco exposure and shifts in the oral microbiome at the population level through three lines of evidence: (1) a shift in microbiota oxygen utilization associated with primary tobacco smoke exposure; (2) consistency of abundance fold changes associated with current smoking and shifts along the gradient of secondhand smoke exposure among nonsmokers; and (3) consistency after adjusting for a priori hypothesized confounders.

A cross-sectional study on the periodontal status and prevalence of red complex periodontal pathogens in a Japanese population

This large-scale study cross-sectionally examined the periodontal status and prevalence of "red complex" bacteria (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) in Japanese adults. A total of 977 participants were enrolled in the study. Probing depth (PD), bleeding on probing (BOP), and bone crest level (BCL) were recorded, and the presence of red complex bacteria in the saliva was examined using polymerase chain reaction. The mean BCL value and the percentage of sites with a PD ≥4 mm or the presence of BOP were significantly higher in older participants. The detection rates of P. gingivalis, T. denticola, and T. forsythia were 46.3%, 76.4%, and 61.1%, respectively. The P. gingivalis detection rate significantly increased with age, while those of T. denticola and T. forsythia were comparably high for all age groups. A close correlation between P. gingivalis and the percentage of sites with PD ≥4 mm was indicated by nonlinear canonical correlation analysis. Current smokers exhibited a more advanced disease condition and a significantly higher P. gingivalis detection rate than non-smokers. In conclusion, periodontal condition worsens with age, and P. gingivalis appears to be the red complex bacterium most closely associated with periodontitis.

Microbiological Response to Periodontal Therapy: A Retrospective Study

BACKGROUND

Periodontitis is a multifactorial infection caused by a complex of pathogenic bacterial species that induce the destruction of periodontal structures.

OBJECTIVE

The aim of this study is to evaluate the presence and bacterial load of six periodontal pathogens bacteria, measured at initial visit and after osseous surgery in patients affected by chronic periodontitis and treated between 2005 and 2007.

METHODS

This cohort study was carried out on a sample of 38 consecutive patients affected by severe chronic periodontitis, diagnosed at baseline on the basis of probing depths equal to 6.68 ± 1.47 mm. On each subject, a microbiological test was performed before periodontal initial therapy and after osseous surgery (one year later). Five compromised teeth were chosen for each patient (the same teeth, before and after surgery), for a total of 190 teeth. Real-time PCR based analysis computed total bacterial load of the samples and quantified six periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum and Prevotella intermedia. Data collection was made consulting medical charts.

RESULTS

Pocket probing depth reduction after surgery was 4.50 ± 1.54 mm (p=0.0001). The mean number of sites with bleeding at baseline was 2.08 ± 1.17 and 0.58 ± 1.00 after surgery (p=0.001). The mean number of sites with suppuration at baseline was 0.26 ± 0.86 and 0 after surgery (p=0.02). Cell count of each pathogen and total cell count were significantly higher at baseline than after surgery. Almost all bacteria presented a mean percentage reduction equal to that of the total count, except for Aa and Pi, which seemed to show a greater resistance. The difference of bacterial load, both before and after surgery, between smokers and non-smokers was not statistically significant (p<0.05). A statistically significant correlation was detected between pocket probing depth variation and bleeding on probing variation before and after the surgery, controlling for age (r=0.6, p=0.001). No significant correlations were observed between pocket probing depth and bacterial loads, except for Pg (r=0.5, p=0.001), Tf (r=0.6, p=0.001) and Td (r=0.4, p=0.02).

CONCLUSIONS

Reduction of presence and bacterial load of the examined periodontal pathogens bacteria after osseous surgery, along with periodontal pocket reduction, appeared to be essential to achieve and maintain periodontal stability over years.

Tobacco-induced suppression of the vascular response to dental plaque

Cigarette smoking presents oral health professionals with a clinical and research conundrum: reduced periodontal vascular responsiveness to the oral biofilm accompanied by increased susceptibility to destructive periodontal diseases. This presents a significant problem, hampering diagnosis and complicating treatment planning. The aim of this review is to summarize contemporary hypotheses that help to explain mechanistically the phenomenon of a suppressed bleeding response to dysbiotic plaque in the periodontia of smokers. The influence of smoke exposure on angiogenesis, innate cell function, the production of inflammatory mediators including cytokines and proteases, tobacco-bacteria interactions, and potential genetic predisposition are discussed.

The Influence of Cigarette Smoking on Various Aspects of Periodontal Health

Tobacco is one of the most important risk factors for oral diseases, including oral cancer, oral mucosal lesions and periodontal diseases. There is substantial evidence suggesting that the risk of oral diseases increases with frequent use of tobacco and that quitting smoking results in reduced risk. In this article, the influence of cigarette smoking on the periodontium will be discussed, giving importance to the effects on immune responses, alveolar bone loss, periodontal pathogens and briefly outlining the negative effects of smoking on wound healing and periodontal treatment procedures.

Alterations in oral microbial flora induced by waterpipe tobacco smoking

Background

Waterpipe smoking is a global health problem and a serious public concern. Little is known about the effects of waterpipe smoking on oral health. In the current study, we examined the alterations of oral microbial flora by waterpipe smoking.

Methods

One hundred adult healthy subjects (59 waterpipe smokers and 41 non-smokers) were recruited into the study. Swabs were taken from the oral cavity and subgingival regions. Standard culturing techniques were used to identify types, frequency, and mean number of microorganisms in cultures obtained from the subjects.

Results

It was notable that waterpipe smokers were significantly associated with a history of oral infections. In subgingiva, Acinetobacter and Moraxella species were present only in waterpipe smokers. In addition, the frequency of Candida albicans was higher in the subgingiva of waterpipe smokers (p = 0.023) while the frequency of Fusobacterium nucleatum was significantly lower in the subgingiva of waterpipe smokers (p = 0.036). However, no change was observed in other tested bacteria, such as Campylobacter species; Viridans group streptococci, Enterobacteriaceae, and Staphylococcus aureus. In oral cavity and when colony-forming units were considered, the only bacterial species that showed significant difference were the black-pigmented bacteria (p < 0.001).

Conclusion

This study provides evidence indicating that some of the oral microflora is significantly altered by waterpipe smoking.

Effect of cigarette smoking on subgingival bacteria in healthy subjects and patients with chronic periodontitis

Background

Cigarette smoking is known to increase the risk of periodontal destruction and developing chronic periodontitis (CP). It is also reported to affect the subgingival bacterial profile among CP patients. However, studies on the effect of smoking on the bacterial profile among healthy subjects are still limited. Therefore, the aim of this study was to investigate the impact of smoking on the subgingival bacterial profile in both healthy adults and CP patients.

Methods

Subgingival plaque samples were collected from CP patients (30 nonsmokers and 9 smokers) and healthy subjects (37 non-smokers and 18 smokers). Genomic DNA was extracted and 25 bacterial species were detected using PCR of 16S rRNA. Comparing smokers to non-smokers from each group was conducted using chi2 and binary logistic regression analysis.

Results

After correcting for confounding factors, the odds of having Slackia exigua, Selenomonas sputigena and Campylobacter rectus was higher among healthy smokers (ORadj = 10.1, 6.62 and 5.62 respectively). While for CP group, the highest odds were observed for Treponema amylovorum, Treponema medium, Slackia exigua and Treponema vincentii (ORadj = 20.7, 7.97, 6.37 and 5.37 respectively) and the increase in Treponema amylovorum was statistically significant (p = 0.05).

Conclusion

Smoking affects the subgingival bacterial profile in healthy individuals and is responsible for the depletion of beneficial bacteria and the increase in periodontopathogenic bacteria. In the CP patient group, our study suggests that subgingival bacteria (particularly Treponema species) make a more substantial contribution in the etiology of CP among non-smokers. Further studies using a larger sample set and more sensitive and quantitative techniques (such as real -time PCR) are needed to enhance our understanding of the exact effect of smoking on subgingival biofilm.

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-017-0359-4) contains supplementary material, which is available to authorized users.

Prevalence of periodontopathogens and Candida spp. in smokers after nonsurgical periodontal therapy - a pilot study

This pilot study aimed to evaluate the influence of smoking on clinical and microbiological parameters after nonsurgical periodontal therapy. Forty-eight subjects were grouped into smokers (SM, n = 24) and nonsmokers (NS, n = 24) and paired according to gender, age, ethnicity, and periodontal status. Both groups received oral hygiene education and scaling and root planing. Clinical evaluation was performed using plaque index (PI), bleeding on probing (BOP), pocket probing depth (PPD), gingival recession (GR), and clinical attachment level (CAL) before instrumentation (baseline) and at 3 and 6 months. The prevalence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Candida albicans, Candida glabrata, Candida tropicalis, and Candida dubliniensis in subgingival biofilm was determined by polymerase chain reaction. The data were statistically analyzed considering p < 0.05. Clinical conditions improved between baseline and 3 months after periodontal treatment. However, NS had a better clinical response, presenting greater PPD reduction and CAL increase in comparison to SM. Periodontal treatment reduced the levels of P. gingivalis, A. actinomycetemcomitans, and T. forsythia individually after 3 months for the NS group and after 6 months for both groups. The prevalence of Candida species was markedly higher in SM than in NS at all time points evaluated. Periodontopathogens associated or not with C. albicans or C. dubliniensis were more prevalent in SM than in NS at baseline and after 3 months. It was concluded that smoking impairs clinical and microbiological responses to periodontal therapy. Periodontopathogens combined or not with some Candida species are resistant to short-term periodontal therapy in SM.

The tobacco-using periodontal patient: role of the dental practitioner in tobacco cessation and periodontal disease management

Although the prevalence of tobacco use has declined in some parts of the world, tobacco use remains a persistent and, in some cases, growing problem that will continue to be a fundamental challenge facing dental practitioners in the decades ahead. Dental practitioners have a unique opportunity and professional obligation to be a positive influence in reducing the economic and social burden inflicted by tobacco use on dental and general health. In this article, the current noninvasive, evidence-based approaches are presented for dental practitioners to help patients avoid initiating tobacco use, to encourage and assist patients in ceasing tobacco use and to address tobacco-induced damage to periodontal supporting tissues.

Periodontal Status and Whole Salivary Cytokine Profile Among Smokers and Never-Smokers With and Without Prediabetes

BACKGROUND

Whole salivary interleukin (IL)-1β and IL-6 in smokers and never-smokers with prediabetes remains uninvestigated. The aim of this study is to assess the periodontal status and whole salivary IL-1β and IL-6 levels among smokers and never-smokers with and without prediabetes (controls).

METHODS

Ninety-five males (45 with prediabetes and 50 systemically healthy controls) were included. Twenty-seven controls and 29 patients with prediabetes were smokers. Periodontal parameters (plaque index, bleeding on probing, probing depth, clinical attachment loss, and marginal bone loss) were measured, and the number of missing teeth were recorded. Fasting blood glucose (FBG) and hemoglobin A1c (HbA1c) levels were recorded. Unstimulated whole saliva samples were collected, unstimulated whole salivary flow rate (UWSFR) was determined, and IL-1β and IL-6 levels were measured. P values <0.05 were considered statistically significant.

RESULTS

FBG (P <0.05) and HbA1c (P <0.05) levels were higher among patients with prediabetes than controls. All patients with prediabetes were hyperglycemic. UWSFR was significantly higher among controls than among patients with prediabetes (P <0.05). Periodontal parameters and whole salivary IL-1β and IL-6 levels were comparable among smokers and never-smokers with prediabetes. Among controls, periodontal parameters and whole salivary IL-1β and IL-6 levels were higher among smokers than never-smokers (P <0.05).

CONCLUSIONS

Among controls, periodontal inflammation was worse, and whole salivary IL-1β and IL-6 levels are higher in smokers than never-smokers. Among patients with prediabetes, periodontal inflammation and whole salivary IL-1β and IL-6 levels were comparable between smokers and never-smokers.

Scratching the surface - tobacco-induced bacterial biofilms

Individual environmental factors, such as iron, temperature and oxygen, are known to have a profound effect on bacterial phenotype. Therefore, it is surprising so little known is about the influence of chemically complex cigarette smoke on bacterial physiology. Recent evidence has demonstrated that tobacco smoke and components alter the bacterial surface and promote biofilm formation in several important human pathogens, including Staphylococcus aureus, Streptococcus mutans, Klebsiella pneumonia, Porphyromonas gingivalis and Pseudomonas aeruginosa. The mechanisms underlying this phenomenon and the relevance to increased susceptibility to infectious disease in smokers and to treatment are reviewed.

Current perspective of the impact of smoking on the progression and treatment of periodontitis

This literature review provides an overview of the current scenario regarding the impact of smoking on the progression and treatment of periodontitis; clinical, microbiological and immunological data from studies from our and other groups are presented. In general, preclinical and clinical data are unanimous in demonstrating that smokers present increased susceptibility, greater severity and faster progression of periodontal disease compared with nonsmokers. The evidence further demonstrates that smokers lose more teeth and have a less favorable response to therapy than do nonsmokers. Although it is well established that smoking significantly impacts on the onset, progression and outcome of periodontal disease, the mechanisms involved remain unclear. More importantly, some of the reported deleterious effects of smoking on periodontal tissues have been reported to be reversible upon participation in smoking-cessation programs. Therefore, clinicians should strongly advise smokers to enroll in cessation strategies, even temporarily, in order to improve the overall outcome.

Implications of tobacco smoking on the oral health of older adults

Cigarette smoking is the foremost health risk issue affecting individuals of all age groups globally. It specifically influences the geriatric population as a result of chronic exposure to toxins. Its role in various systemic and oral diseases including cancer, premalignant lesions, periodontitis, tooth loss, dental caries and implant failures is well established. Smoking causes immuno-inflammatory imbalances resulting in increased oxidative stress in the body. The latter hastens the immunosenescence and inflammaging process, which increases the susceptibility to infections. Thus, implementation of smoking cessation programs among older adults is imperative to prevent the development and progression of oral and systemic diseases. The present review focuses on smoking-associated oral health problems in older adults, and the steps required for cessation of the habit.

Neutrophils alter epithelial response to Porphyromonas gingivalis in a gingival crevice model

A gingival crevice model (epithelial cell-Porphyromonas gingivalis-neutrophil) was established and used to profile gingipain, matrix metalloproteinase (MMP), MMP mediators [neutrophil gelatinase-associated lipocalin (NGAL) and tissue inhibitor of metalloproteinases 1 (TIMP-1)] and cytokine networks. Smoking is the primary environmental risk factor for periodontitis. Therefore, the influence of cigarette smoke extract (CSE) was also monitored in the same model. Porphyromonas gingivalis alone induced low levels of interleukin-1β and interleukin-8 from epithelial cells, but high levels of both cytokines were produced on the addition of neutrophils. Exposure to CSE (100 and 1000 ng ml(-1) nicotine equivalency) significantly compromised P. gingivalis-induced cytokine secretion (both P < 0.05). P. gingivalis induced impressive secretion of NGAL (P < 0.05) that was not influenced by CSE. The influence of CSE on gingipain production was strain-specific. Purified gingipains effectively and rapidly degraded both TIMP-1 and MMP-9. Induction of large amounts of NGAL, degradation of TIMP-1, and increased gingipain activity would each be expected to prolong collagen degradation and promote disease progression. However, gingipains also degrade MMP-9. Hence, P. gingivalis exerts a complex influence on the proteolytic balance of a gingival crevice model. Exposure to CSE reduces the proinflammatory cytokine burden, which may be expected to promote P. gingivalis survival. In addition to novel findings that provide mechanistic insight into periodontal disease progression, these results are in keeping with the recognized clinical dogma of decreased inflammation/increased disease in smokers. This straightforward gingival crevice model is established as a suitable vehicle for the elucidation of mechanisms that contribute to susceptibility to periodontitis.

Tobacco smoke augments Porphyromonas gingivalis-Streptococcus gordonii biofilm formation

Smoking is responsible for the majority of periodontitis cases in the US and smokers are more susceptible than non-smokers to infection by the periodontal pathogen Porphyromonas gingivalis. P. gingivalis colonization of the oral cavity is dependent upon its interaction with other plaque bacteria, including Streptococcus gordonii. Microarray analysis suggested that exposure of P. gingivalis to cigarette smoke extract (CSE) increased the expression of the major fimbrial antigen (FimA), but not the minor fimbrial antigen (Mfa1). Therefore, we hypothesized that CSE promotes P. gingivalis-S. gordonii biofilm formation in a FimA-dependent manner. FimA total protein and cell surface expression were increased upon exposure to CSE whereas Mfa1 was unaffected. CSE exposure did not induce P. gingivalis auto-aggregation but did promote dual species biofilm formation, monitored by microcolony numbers and depth (both, p<0.05). Interestingly, P. gingivalis biofilms grown in the presence of CSE exhibited a lower pro-inflammatory capacity (TNF-α, IL-6) than control biofilms (both, p<0.01). CSE-exposed P. gingivalis bound more strongly to immobilized rGAPDH, the cognate FimA ligand on S. gordonii, than control biofilms (p<0.001) and did so in a dose-dependent manner. Nevertheless, a peptide representing the Mfa1 binding site on S. gordonii, SspB, completely inhibited dual species biofilm formation. Thus, CSE likely augments P. gingivalis biofilm formation by increasing FimA avidity which, in turn, supports initial interspecies interactions and promotes subsequent high affinity Mfa1-SspB interactions driving biofilm growth. CSE induction of P. gingivalis biofilms of limited pro-inflammatory potential may explain the increased persistence of this pathogen in smokers. These findings may also be relevant to other biofilm-induced infectious diseases and conditions.

Influence of smoking on gingival crevicular fluid cytokines in severe chronic periodontitis

AIM

The aim of this study was to compare the expression of 22 chemokines and cytokines in gingival crevicular fluid (GCF) from smokers and non-smokers with periodontitis and periodontally healthy control subjects.

MATERIALS AND METHODS

Forty subjects with generalized severe chronic periodontitis (20 smokers and 20 non-smokers) and 12 periodontally healthy control subjects participated in this study. Four diseased and two healthy sites were selected from each of the periodontitis subjects. GCF samples were collected and cytokines analysed utilizing a multiplexed immunoassay (Luminex(®) ). Statistical analyses employed non-parametric tests including the Mann-Whitney and Wilcoxon matched-pairs signed-rank tests.

RESULTS

Compared with healthy control subjects, GCF in subjects with chronic periodontitis contained significantly higher amounts of interleukin (IL)-1α, IL-1β, IL-6, IL-12(p40) (pro-inflammatory cytokines); IL-8, macrophage chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, regulated on activation normal T-cell expressed and secreted (RANTES) (chemokines); IL-2, IFN-γ, IL-3, IL-4 (Th1/Th2 cytokines); IL-15 [regulator of T-cells and natural killer (NK) cells]. Smokers displayed decreased amounts of pro-inflammatory cytokines [IL-1α, IL-6, IL-12(p40)], chemokines (IL-8, MCP-1, MIP-1, RANTES), and regulators of T-cells and NK cells (IL-7, IL-15).

CONCLUSIONS

Periodontitis subjects had significantly elevated cytokine and chemokine profiles. Smokers exhibited a decrease in several pro-inflammatory cytokines and chemokines and certain regulators of T-cells and NK-cells. This reflects the immunosuppressant effects of smoking which may contribute to an enhanced susceptibility to periodontitis.

Effect of teenage smoking on the prevalence of periodontal bacteria

The aim of our study was to investigate how teenage smoking affects the prevalence of periodontal bacteria and periodontal health with the hypothesis that smoking increases the prevalence of the bacteria. Oral health of 264 adolescents (15- to 16-year-olds) was clinically examined, and their smoking history was recorded. The participants also filled in a structured questionnaire recording their general health and health habits. Pooled subgingival plaque samples were taken for polymerase chain reaction analysis of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola. The prevalence of P. intermedia (21% vs. 4%, p = 0.01) and T. forsythia and T. denticola (23% vs. 8%, p < 0.05, for both) was higher among female smokers than among non-smokers. T. forsythia and T. denticola were more often associated with bleeding on probing (29% vs. 12%; 25% vs. 10%, respectively) and deep pockets (25% vs. 15%; 23% vs. 10%, respectively) with smokers than non-smokers. Among the girls, a significant association was found between pack-years and the prevalence of P. nigrescens (p < 0.007). In both genders, A. actinomycetemcomitans and P. gingivalis were rare in this study. To conclude, periodontal bacteria were associated with higher periodontal index scores among all teenage smokers. Smoking girls harbored more frequently certain periodontal bacteria than non-smokers, but this was not seen in boys. Hence, our study hypothesis was only partly confirmed.

Tobacco upregulates P. gingivalis fimbrial proteins which induce TLR2 hyposensitivity

BACKGROUND

Tobacco smokers are more susceptible to periodontitis than non-smokers but exhibit reduced signs of clinical inflammation. The underlying mechanisms are unknown. We have previously shown that cigarette smoke extract (CSE) represents an environmental stress to which P. gingivalis adapts by altering the expression of several virulence factors - including major and minor fimbrial antigens (FimA and Mfa1, respectively) and capsule - concomitant with a reduced pro-inflammatory potential of intact P. gingivalis.

METHODOLOGY/PRINCIPAL FINDINGS

We hypothesized that CSE-regulation of capsule and fimbrial genes is reflected at the ultrastructural and functional levels, alters the nature of host-pathogen interactions, and contributes to the reduced pro- inflammatory potential of smoke exposed P. gingivalis. CSE induced ultrastructural alterations were determined by electron microscopy, confirmed by Western blot and physiological consequences studied in open-flow biofilms. Inflammatory profiling of specific CSE-dysregulated proteins, rFimA and rMfa1, was determined by quantifying cytokine induction in primary human innate and OBA-9 cells. CSE up-regulates P. gingivalis FimA at the protein level, suppresses the production of capsular polysaccharides at the ultrastructural level, and creates conditions that promote biofilm formation. We further show that while FimA is recognized by TLR2/6, it has only minimal inflammatory activity in several cell types. Furthermore, FimA stimulation chronically abrogates the pro-inflammatory response to subsequent TLR2 stimulation by other TLR-2-specific agonists (Pam3CSK4, FSL, Mfa1) in an IkappaBalpha- and IRAK-1-dependent manner.

CONCLUSIONS/SIGNIFICANCE

These studies provide some of the first information to explain, mechanistically, how tobacco smoke changes the P. gingivalis phenotype in a manner likely to promote P. gingivalis colonization and infection while simultaneously reducing the host response to this major mucosal pathogen.

Interleukin-1 and interleukin-8 in nicotine- and lipopolysaccharide-exposed gingival keratinocyte cultures

BACKGROUND AND OBJECTIVE

Tobacco use is associated with increased periodontal destruction in both cigarette smokers and smokeless tobacco users. Gingival keratinocytes are the first cells in contact with microbial and tobacco components and play a key role in the innate immune response to these agents. The objective of this study was to evaluate the effect of nicotine and bacterial lipopolysaccharide (LPS) alone and in combination on gingival keratinocyte production of interleukin-1 alpha (IL-1 alpha) and interleukin-8 (IL-8).

MATERIAL AND METHODS

Gingival keratinocyte cultures were established from 10 healthy, non-tobacco-using subjects. The cells were stimulated for 24 h with 1 mum or 1 mm nicotine and/or 10 microg/mL Escherichia coli or Porphyromonas gingivalis LPS. Interleukin-1 alpha and IL-8 proteins were quantified using ELISAs.

RESULTS

Compared with untreated cultures, 1 mm nicotine stimulated production of IL-1 alpha (p < 0.001); E. coli and P. gingivalis LPS increased IL-8 production (p = 0.0014 and p = 0.0232, respectively). A combination of nicotine and LPS produced the highest cytokine quantities. Amounts of IL-1 alpha and IL-8 following 1 mm nicotine and LPS exposure were significantly greater than in untreated cultures (p < 0.001). Interleukin-8 was also responsive to 0.1 mum nicotine combined with E. coli or P. gingivalis LPS compared with control cultures (p < 0.0001 and p = 0.0029, respectively). Both cytokines tended to be elevated following the combined treatment relative to nicotine or LPS treatment alone.

CONCLUSION

These results demonstrate that nicotine and LPS differentially regulate IL-1 and IL-8 production by gingival keratinocytes. Combined treatment tended to elevate cytokine production further, which may have implications for the progression of periodontitis in tobacco users.

Tobacco-induced alterations to Porphyromonas gingivalis-host interactions

Smokers are more susceptible than non-smokers to persistent infection by Porphyromonas gingivalis, a causative agent of periodontitis. Patients who smoke exhibit increased susceptibility to periodontitis and are more likely to display severe disease and be refractory to treatment. Paradoxically, smokers demonstrate reduced clinical inflammation. We show that P. gingivalis cells exposed to cigarette smoke extract (CSE) induce a lower proinflammatory response (tumour necrosis factor-alpha, interleukin-6, interleukin-12 p40) from monocytes and peripheral blood mononuclear cells than do unexposed bacteria. This effect is reversed when CSE-exposed bacteria are subcultured in fresh medium without CSE. Using microarrays representative of the P. gingivalis genome, CSE-exposure resulted in differential regulation of 6.8% of P. gingivalis genes, including detoxification and oxidative stress-related genes; DNA repair genes; and multiple genes related to P. gingivalis virulence, including genes in the major fimbrial and capsular operons. Exposure to CSE also altered the expression of outer membrane proteins, most notably by inducing the virulence factors RagA and RagB, and a putative lipoprotein cotranscribed with the minor fimbrial antigen. Therefore, CSE represents an environmental stress to which P. gingivalis adapts by altering gene expression and outer membrane proteins. These changes may explain, in part, the altered virulence and host-pathogen interactions that have been documented in vivo in smokers with periodontal disease.

Tobacco use increases susceptibility to bacterial infection

Active smokers and those exposed to secondhand smoke are at increased risk of bacterial infection. Tobacco smoke exposure increases susceptibility to respiratory tract infections, including tuberculosis, pneumonia and Legionnaires disease; bacterial vaginosis and sexually transmitted diseases, such as chlamydia and gonorrhoea; Helicobacter pylori infection; periodontitis; meningitis; otitis media; and post-surgical and nosocomial infections. Tobacco smoke compromises the anti-bacterial function of leukocytes, including neutrophils, monocytes, T cells and B cells, providing a mechanistic explanation for increased infection risk. Further epidemiological, clinical and mechanistic research into this important area is warranted.

Etiological analysis of initial colonization of periodontal pathogens in oral cavity

It is unclear when the initial colonization by periodontal pathogens occurs in the oral cavity. Therefore, we report here the association between specific age groups and the time when the initial colonization by periodontal pathogens occurs in the oral cavity in such groups. Findings are based on an epidemiological analysis of the prevalence of five periodontal pathogens in the oral cavities of a wide range of age populations, from newborn to elderly, who were randomly selected in a geographic region of Brazil. These periodontal pathogens include Campylobacter rectus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Tannerella forsythia and were analyzed in the bacterial samples isolated from gingival sulcus, the dorsum of the tongue, and cheek mucosa of diverse age groups, using a bacterial DNA-specific PCR method. Results indicated that there are distinct age-related groups where initial colonization by the five periodontal pathogens examined in this study can be detected and that the presence of teeth is a permissive factor for colonization by P. gingivalis, P. intermedia, and T. forsythia. Although it remains unclear exactly how or when target pathogens colonize healthy subjects, an understanding of age-related groups does provide a potentially useful tool in the early detection and prevention of periodontitis in healthy individuals.

Mechanical Therapy With Adjunctive Minocycline Microspheres Reduces Red-Complex Bacteria in Smokers

BACKGROUND

Smoking increases the risk for periodontal disease and reduces the healing response. We examined the antimicrobial and clinical effects of scaling and root planing (SRP) with and without minocycline HCl 1 mg microspheres (MM) relative to smoking status in subjects with periodontitis.

METHODS

A total of 127 subjects (46 never smokers, 44 former smokers, and 37 current smokers) with moderate to advanced periodontitis were randomized to receive MM + SRP (N = 62) or SRP alone (N = 65). Subgingival plaque samples collected at baseline and day 30 were examined for the presence of 40 periodontal bacteria by DNA probe analysis.

RESULTS

MM + SRP reduced red-complex bacteria (RCB) numbers and proportions to a greater extent than SRP alone, irrespective of smoking status. RCB numbers were not reduced by SRP in current smokers. The difference in the reduction in numbers of RCB by SRP relative to MM + SRP in current smokers was statistically significant (P <0.05). Numbers and proportions of orange complex bacteria (OCB) were reduced in all groups treated with MM + SRP. Proportions of OCB increased in current smokers treated with SRP alone. In current smokers, MM + SRP significantly reduced probing depth (PD), increased clinical attachment level (CAL), and reduced bleeding on probing (BOP) to a greater extent than SRP alone (P <0.05).

CONCLUSIONS

SRP alone was ineffective at reducing numbers or proportions of RCB or OCB in current smokers, whereas MM + SRP significantly reduced both. MM + SRP also improved PD, BOP, and CAL to a greater extent than SRP alone independent of smoking status.

Population-based study of salivary carriage of periodontal pathogens in adults

Large, general population-based data on carriage rates of periodontal pathogens hardly exist in the current literature. The objectives of the present study were to examine the salivary detection of Aggregatibacter (formerly Actinobacillus) actinomycetemcomitans, Campylobacter rectus, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, and Treponema denticola in a representative sample of the adult population living in southern Finland and to clarify which determinants are associated with the presence of these pathogens in saliva. 16S rRNA-based PCR methods with species-specific primers were employed to determine the presence of the six target bacteria in stimulated saliva samples, which were available from 1,294 subjects aged > or =30 years. The age group, gender, level of education, marital status, smoking history, number of teeth, and number of teeth with deepened pockets were included in the statistical analysis. In general, the carriage of periodontal pathogens was common, since at least one of the examined pathogens was found in 88.2% of the subjects. In descending order, the total detection rates were 56.9%, 38.2%, 35.4%, 31.3%, 20.0%, and 13.9% for T. forsythensis, T. denticola, P. gingivalis, C. rectus, A. actinomycetemcomitans, and P. intermedia, respectively. Age per se was strongly associated with the carriage of P. gingivalis (P = 0.000), and the level of education with that of T. denticola (P = 0.000). There was an association between the number of teeth with deepened pockets and carriage of P. gingivalis (P = 0.000), P. intermedia (P = 0.000), T. denticola (P = 0.000), and A. actinomycetemcomitans (P = 0.004). The data suggest that distinct species have a different carriage profile, depending on variables such as age, educational level, and periodontal status.