Relationship of cigarette smoking to the subgingival microbiota

Longitudinal Study of the Association Between Smoking as a Periodontitis Risk and Salivary Biomarkers Related to Periodontitis

BACKGROUND

Insufficient data exist regarding the long-term influence of lifestyle factors including smoking on periodontal health. The objective of this study was to examine the prospective association between smoking and periodontal disease progression and the effects of smoking on salivary biomarkers related to periodontitis.

METHODS

Probing depth (PD) was measured at health checkups of workers in 1999 and 2003; additionally, lifestyle information was obtained through a questionnaire. In 2003, 219 of 256 (86%) workers examined at baseline completed PD measurements; saliva samples were also collected. Change in PD was used for assessment of periodontitis progression when three or more sites displayed an increase of >or=2 mm over 4 years. Salivary biomarker levels were determined by real-time polymerase chain reaction and enzyme assay. Statistical methods included bivariate and multivariate regression analyses.

RESULTS

In the multiple logistic model, in which lifestyle-related factors served as independent variables, significant variables were current smoking and hours of sleep; respective odds ratios were 2.3 and 2.1. Additionally, 38.5% of periodontal disease progression was attributable to current smoking. Moreover, pack-years of smoking showed a dose-response relationship with disease progression. Levels of salivary markers including prostaglandin E(2), lactoferrin, albumin, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase were significantly lower in current smokers than in non-current smokers. However, no meaningful differences in the proportions of six periodontal pathogens were observed between current and non-current smokers.

CONCLUSIONS

Smoking exerted the greatest influence on periodontitis risk among lifestyle factors. Smoking may suppress the host-defense system, which may promote periodontal disease progression.

Periodontal infection profiles in type 1 diabetes

OBJECTIVES

We investigated the levels of subgingival plaque bacteria and serum IgG responses in patients with type 1 diabetes and non-diabetic controls of comparable periodontal status.

MATERIAL AND METHODS

Fifty type 1 diabetes patients (mean duration 20.3 years, range 6-41) were age-and gender-matched with 50 non-diabetic individuals with similar levels of periodontal disease. Full-mouth clinical periodontal status was recorded, and eight plaque samples/person were collected and analysed by checkerboard hybridization with respect to 12 species. Homologous serum IgG titres were assessed by checkerboard immunoblotting. In a sub-sample of pairs, serum cytokines and selected markers of cardiovascular risk were assessed using multiplex technology.

RESULTS

Among the investigated species, only levels of Eubacterium nodatum were found to be higher in diabetic patients, while none of the IgG titres differed between the groups, both before and after adjustments for microbial load. Patients with diabetes had significantly higher serum levels of soluble E-selectin (p=0.04), vascular cell adhesion molecule-1 (VCAM-1; p=0.0008), adiponectin (p=0.01) and lower levels of plasminogen activator inhibitor-1 (PAI-1; p=0.02).

CONCLUSIONS

After controlling for the severity of periodontal disease, patients with type 1 diabetes and non-diabetic controls showed comparable subgingival infection patterns and serum antibody responses.

Nicotine treatment induces expression of matrix metalloproteinases in human osteoblastic Saos-2 cells

Tobacco smoking is an important risk factor for the development of severe periodontitis. Recently, we showed that nicotine affected mineralized nodule formation, and that nicotine and lipopolysaccharide stimulated the formation of osteoclast-like cells by increasing production of macrophage colony-stimulating factor (M-CSF) and prostaglandin E2 (PGE2) by human osteoblastic Saos-2 cells. In the present study, we examined the effects of nicotine on the expression of matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs), the plasminogen activation system including the component of tissue-type plasminogen activator (tPA), urokinase-type PA (uPA), and PA inhibitor type 1 (PAI-1), alpha7 nicotine receptor, and c-fos. We also examined the effect of the nicotine antagonist D-tubocurarine on nicotine-induced expression of MMP-1. Gene expression was examined using real-time polymerase chain reaction (PCR) to estimate mRNA levels. In addition, expression of the MMP, TIMP, uPA, tPA, and PAI-1 proteins was determined by Western blotting analysis. Nicotine treatment caused expression of MMP-1, 2, 3, and 13, but not MMP-14, to increase significantly after 5 or 10 d of culture; MMP-14 expression did not change through day 14. Enhancement of MMP-1 expression by nicotine treatment was eliminated by simultaneous treatment with D-tubocurarine. In the presence of nicotine, expression of uPA, PAI-1, or TIMP-1, 2, 3, or 4 did not change over 14 d of culture, whereas expression of tPA increased significantly by day 7. Nicotine also increased expression of the alpha7 nicotine receptor and c-fos genes. These results suggest that nicotine stimulates bone matrix turnover by increasing production of tPA and MMP-1, 2, 3, and 13, thereby tipping the balance between bone matrix formation and resorption toward the latter process.

Association of Eubacterium nodatum and Treponema denticola with human periodontitis lesions

BACKGROUND

The purpose of the present investigation was to compare the levels, proportions and percentage of sites colonized by 40 bacterial species in subgingival plaque samples from periodontally healthy subjects and patients with chronic periodontitis to seek possible pathogens other than the consensus pathogens Porphyromonas gingivalis and Tannerella forsythia.

METHOD

Subgingival plaque samples were taken from the mesial aspect of each tooth in 635 subjects with chronic periodontitis and 189 periodontally healthy subjects. The samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization (total samples = 21,832). Mean counts, % DNA probe counts and percentage of sites colonized at >10(5) were determined for each species in each subject and then averaged in each clinical group. Significance of difference between groups was determined using the Mann-Whitney test. Association between combinations of species and periodontal status was examined by stepwise logistic regression analysis. Analyses were repeated using a subset of subjects from both clinical groups who had proportions of P. gingivalis plus T. forsythia less than the median (4.42%) found in periodontally healthy subjects. All analyses were adjusted for multiple comparisons.

RESULTS

For the 824 subjects the consensus pathogens P. gingivalis and T. forsythia as well as Eubacterium nodatum and Treponema denticola had significantly higher mean counts, proportions and percentage of sites colonized in samples from subjects with periodontitis than from periodontally healthy subjects. There were significantly more Capnocytophaga gingivalis, Streptococcus gordonii and Veillonella parvula in periodontally healthy subjects. E. nodatum, T. denticola, Streptococcus oralis, Streptococcus intermedius, Fusobacterium nucleatum ssp. vincentii all had higher counts and proportions in diseased than healthy subjects who had low proportions of P. gingivalis and T. forsythia. Logistic regression analysis indicated that the same species groups were associated with disease status after adjusting for the proportions of the other species.

CONCLUSIONS

This investigation confirmed the strong association of P. gingivalis and T. forsythia with chronic periodontitis and emphasized a strong association of E. nodatum and T. denticola with periodontitis whether in the presence or absence of high levels of the consensus pathogens. Other species, including S. oralis, Eikenella corrodens, S. intermedius and F. nucleatum ssp. vincentii, were associated with disease when P. gingivalis and T. forsythia were present in low proportions.

Public health implications of smokeless tobacco use as a harm reduction strategy

Harm reduction strategies involve promoting a product that has adverse health consequences as a substitute for one that has more severe adverse health consequences. Smokeless tobacco low in nitrosamine content offers potential benefits in reducing smoking prevalence rates. Possible harm arises from the potential for such products to serve as a gateway to more harmful tobacco products, public misinterpretation of "less harmful" as "safe," distraction from the public health goal of tobacco elimination, and ethical issues involved in advising those marketing these harmful products. We offer a research agenda to provide a stronger basis for evaluating the risks and benefits of smokeless tobacco as a means of reducing the adverse health effects of tobacco.

Association between passive smoking and salivary markers related to periodontitis

OBJECTIVES

The mechanism of passive smoking in terms of development of periodontitis has not been investigated. This study examined the effect of passive smoking on salivary markers related to periodontitis.

METHODS

Periodontal status was evaluated on the basis of probing pocket depth and clinical attachment level in 273 workers. Salivary marker levels were determined by enzyme assay including enzyme-linked immunosorbent assay. Six periodontal pathogens in saliva were assessed using real-time PCR methodology. Non-, passive and active smokers were defined as subjects exhibiting salivary cotinine levels of 0 (53 subjects), 1-7 (118) and > or = 8 ng/ml (102).

RESULTS

Levels of salivary markers, including IL-1beta, lactoferrin, albumin and aspartate aminotransferase (AST), were elevated significantly in passive smokers relative to non-smokers. Additionally, these marker levels, with the exception of IL-1beta, decreased significantly in active smokers in comparison with passive smokers. However, no meaningful differences in percentages of periodontal pathogens were observed between non- and passive smokers. Multiple linear regression analyses were performed for each marker utilizing age, gender, cotinine level and periodontal status as independent variables. IL-1beta, albumin and AST were independently associated with cotinine level.

CONCLUSION

Passive smoke exposure leads to elevation of IL-1beta, albumin and AST levels in saliva.

Periodontal Status in Smokers and Never-Smokers: Clinical Findings and Real-Time Polymerase Chain Reaction Quantification of Putative Periodontal Pathogens

BACKGROUND

Smoking is a well-known risk factor for destructive periodontal disease, but its relationship with periodontal status and subgingival microbiota remains unclear. Inherent limitations of microbiological methods previously used may partly explain these mixed results, and real-time polymerase chain reaction (PCR) has been presented as a valid alternative. The aim of the present study was to investigate the clinical condition and microbiological profile of patients with chronic periodontitis as related to the habit of smoking.

METHODS

Fifty patients (33 to 59 years old), 25 smokers and 25 never-smokers, constituted the sample. The visible plaque index (VPI), gingival bleeding index (GBI), bleeding on probing (BOP), periodontal probing depth (PD), clinical attachment loss (CAL), and gingival crevicular fluid (GCF) volume were recorded. Real-time PCR quantified Porphyromonas gingivalis, Micromonas micros, Dialister pneumosintes, Actinobacillus actinomycetemcomitans and total bacteria in subgingival samples.

RESULTS

Smokers and never-smokers showed similar values for VPI, GBI, and BOP. Smokers had deeper PD in buccal/lingual sites and higher CAL independently of the tooth surface. The GCF volume was smaller in smokers, independent of the PD. Similar amounts of total bacteria and P. gingivalis were observed for both groups. Significantly higher numbers of D. pneumosintes and M. micros were present in smokers and associated with moderate and deep pockets. When heavy smokers were considered, higher counts of total bacteria, M. micros, and D. pneumosintes were observed.

CONCLUSIONS

Smoking seems to have a detrimental impact on the periodontal status and microbiological profile of patients with periodontitis. Compared to never-smokers, smokers had deeper pockets, greater periodontal destruction, and higher counts of some putative periodontal pathogens.

The Diagnosis of Periodontal Disease in Private Practice

BACKGROUND

Periodontal disease is an inflammatory reaction to the bacteria in dental plaque. The present study compared the prevalence of periodontal disease in patients using as a diagnostic either probing depth measurements, an inflammatory marker such as numbers of white blood cells in plaque samples, or microbiological markers such as the microscopic count and the benzoyl-DL-arginine naphthylamide (BANA) test.

METHODS

Teeth with the most inflammation and/or deepest pockets in each quadrant were probed and subgingival plaque was sampled from 1,043 consecutive new patients enrolled in a private practice. Multivariate "diagnostic" models were developed based upon the probing depth (general linear models), percentage of white blood cell-positive and percentage of BANA-positive plaques (logistic regression models) to determine the prevalence of patients with periodontal disease.

RESULTS

Plaque samples were removed from 3,694 sites. Fifty-two percent of sampled pockets were >4 mm; 49% of sites were inflamed, using the presence of white blood cells, and 28% were infected using the BANA test. Diagnostic models were highly significant at P<0.0001. The white blood cell model was the most parsimonious as demonstrated by the lowest Akaike information criteria statistic and had the highest receiver operator characteristic (ROC) curve relative to the probing depth and BANA models.

CONCLUSIONS

Periodontal disease can be diagnosed chairside by the presence of white blood cells in plaque samples, a finding that reflects the inflammatory nature of the disease process. This approach would reduce the misclassification of subjects as having periodontal disease (130 patients in the present study who had pockets) but minimal evidence of an inflammatory response.

Aggressive Periodontitis Among Young Israeli Army Personnel

BACKGROUND

The aim of this study was to assess the prevalence of aggressive periodontitis among young Israeli army recruits and to evaluate its association with smoking habits and ethnic origin.

METHODS

The study population consisted of 642 young army recruits (562 men [87.5%] and 80 women [12.5%]), aged 18 to 30 years (average: 19.6 +/- 1.6 years), who arrived at a military dental clinic for dental examinations between January and December 2004. Subjects filled out a questionnaire regarding their ethnic origin and family periodontal history, followed by radiographs and a clinical periodontal examination of four first molars and eight incisors.

RESULTS

Aggressive periodontitis was found in 5.9% of the subjects (4.3% localized and 1.6% generalized). At least one site with a probing depth > or =5 mm was found in 20.1% of the subjects. A radiographic distance between crestal bone height and the cemento-enamel junction >3 mm was found in 43 (6.7%) subjects. Current smokers (39.9%) (P = 0.03) and subjects of North African origin (P <0.0001) correlated with a high prevalence of aggressive periodontitis.

CONCLUSION

A relatively high prevalence of aggressive periodontitis was found in young Israeli army recruits, which was particularly associated with smoking and ethnic origin.

Influence of smoking on osseointegrated implant failure: a meta-analysis

The aim of this study was to examine the influence of smoking on osseointegrated implant failure by performing a meta-analysis. A computerized literature search using PubMed database (in English) and Japana Centra Revuo Medicina (in Japanese) was carried out to identify all relevant studies. Among 175 studies identified and chosen for detailed review, 19 were appropriate for inclusion in our meta-analysis. When smokers were compared with non-smokers, odds ratio (OR) for osseointegrated implant failure was significantly elevated (OR 2.17, 95% confidence intervals (CI), 1.67-2.83). Seven studies were appropriate to examine the influence of intra-oral location (maxillary arch vs. mandibular arch) of implant failure on smoking. The OR for implant failure occurring in the maxillary arch was significantly elevated (OR 2.06, 95% CI, 1.61-2.65), whereas the OR in the mandibular arch did not demonstrate a significant increased risk associated with smoking (OR 1.32, 95% CI, 0.72-2.4). Our meta-analysis revealed a significant relationship between smoking and the risk of osseointegrated implant failure, more particularly those implants located in the maxillary arch.

The Influence of Current and Former Smoking on Gingival Bleeding: The Hisayama Study

BACKGROUND

Previous studies have shown that smoking is a risk factor for periodontitis and that it has a suppressive effect on gingival bleeding. This study examined the relationship between smoking, including past smoking, and periodontal conditions, mainly gingival bleeding, in a community-based health investigation.

METHODS

Smoking status was examined in 958 subjects, along with the quantity of tobacco currently or previously smoked (never, former light, former heavy, current light, and current heavy). We analyzed the influence of smoking on probing depth (PD), clinical attachment loss (CAL), and gingival bleeding on probing (BOP).

RESULTS

In multivariate logistic regression analyses, current heavy smokers were at a significantly greater risk for having a higher proportion of teeth with PD > or =4 mm and a higher proportion of teeth with CAL > or =5 mm; however, they had a lower risk for having a high BOP than did those who had never smoked. Moreover, both former light and former heavy smokers had significantly lower risks for high BOP. When the analysis was limited to subjects with PD > or =4 mm, former heavy and current heavy smokers showed a significant suppression of high BOP compared to never smokers.

CONCLUSION

This study suggests that smoking is significantly associated with PD and CAL and that current and past smoking has a suppressive effect on BOP.

Technology development to explore the relationship between oral health and the oral microbial community

The human oral cavity contains a complex microbial community that, until recently, has not been well characterized. Studies using molecular tools have begun to enumerate and quantify the species residing in various niches of the oral cavity; yet, virtually every study has revealed additional new species, and little is known about the structural dynamics of the oral microbial community or how it changes with disease. Current estimates of bacterial diversity in the oral cavity range up to 700 species, although in any single individual this number is much lower. Oral microbes are responsible for common chronic diseases and are suggested to be sentinels of systemic human diseases. Microarrays are now being used to study oral microbiota in a systematic and robust manner. Although this technology is still relatively young, improvements have been made in all aspects of the technology, including advances that provide better discrimination between perfect-match hybridizations from non-specific (and closely-related) hybridizations. This review addresses a core technology using gel-based microarrays and the initial integration of this technology into a single device needed for system-wide studies of complex microbial community structure and for the development of oral diagnostic devices.

Influence of Combinations of Bacteria on the Levels of Prostaglandin E2, Interleukin-1β, and Granulocyte Elastase in Gingival Crevicular Fluid and on the Severity of Periodontal Disease

BACKGROUND

The aim of this study was to investigate the simultaneous presence of periodontal microbiota on inflammatory markers in gingival crevicular fluid from individuals with periodontal diseases.

METHODS

A total of 82 individuals with periodontal disease (mean age: 54.3 +/- 3.0 years) and 31 periodontally healthy individuals (mean age: 53.2 +/- 3.0 years) were randomly chosen and underwent clinical oral examinations in 2003 with the determination of the dental plaque index (PI), gingival index (GI), and periodontal probing depth (PD). The simultaneous presence of polymerase chain reaction (PCR)-assessed periodontal bacteria, levels of prostaglandin E(2) (PGE(2)), granulocyte elastase, interleukin 1-beta (IL-1beta), and total protein concentration were determined from the pockets. Marginal bone height percent was measured on x-rays. Analysis of variance and chi(2) tests were used to analyze the results.

RESULTS

In sites with Tannerella forsythensis, levels of PGE(2) (pg/site), granulocyte elastase (monoclonal antibodies (mAbs)/site), and total protein (mg/ml) were significantly higher than in sites without T. forsythensis (P <0.05, P <0.01, and P <0.05, respectively). Those with periodontal disease with simultaneous presence of T. forsythensis and Porphyromonas gingivalis, or T. forsythensis and Prevotella nigrescens, showed significantly higher PI and GI, deeper PD, more loss of attachment, and more release of PGE(2) and granulocyte elastase than did periodontitis patients without these bacteria.

CONCLUSION

The simultaneous presence of T. forsythensis and P. gingivalis, or T. forsythensis and P. nigrescens, seemed to promote the release of subgingival inflammatory mediators and seemed to be associated with more severe periodontal disease.

Prospective Study of Alcohol Consumption and Risk of Oral Premalignant Lesions in Men

Recent case-control studies indicate that alcohol increases the risk of oral premalignant lesions (OPL) among tobacco users, but the independent association between alcohol and OPL remains unclear. We prospectively evaluated the association between alcohol consumption and the incidence of OPL. Participants were 41,458 men in the Health Professionals Follow-up Study. Alcohol consumption was assessed every 4 years using validated food frequency questionnaires. We confirmed clinically or histopathologically diagnosed OPL events occurring between 1986 and 2002 by medical record review (193 cases). Multivariate-adjusted relative risks of OPL were calculated from Cox proportional hazards models. With detailed control for tobacco and other variables, multivariate relative risks (95% confidence intervals) were 1.7 (0.9-3.2) for drinkers of 0.1 to 14.9 g/d, 2.9 (1.5-5.6) for 15 to 29.9 g/d, and 2.5 (1.3-5.1) for > or =30 g/d, compared with nondrinkers. Approximately one additional drink per day (12.5 g) was associated with a 22% increase in risk (P < 0.001). The associations did not vary by beverage type, frequency, or consumption with meals. Results were similar when restricted to cases of oral epithelial dysplasia. Alcohol increased OPL risk in never-users of tobacco as well as in past or current users. An interaction between alcohol and tobacco was apparent by their more-than-additive joint effects. Alcohol is an independent risk factor for OPL, regardless of beverage type or drinking pattern. Recommendations to reduce alcohol intake have the potential to reduce incidence of OPL in nonsmokers and smokers alike.

Nicotine affects mineralized nodule formation by the human osteosarcoma cell line Saos-2

Several in vitro and in vivo studies have indicated that tobacco smoking may be an important risk factor for the development and severity of inflammatory periodontal disease. In the present study, we examined the effect of nicotine on cell proliferation, alkaline phosphatase (ALPase) activity, mineralized nodule formation, and the expression of extracellular matrix proteins in the human osteosarcoma cell line Saos-2. The cells were cultured with Dulbecco's modified Eagle medium containing 10% fetal bovine serum with 0, 10(-4) M, and 10(-3) M nicotine for up to 14 days. Mineralized nodule formation was examined by alizarin red staining, and the calcium content in mineralized nodules was determined using a calcium E-test kit. The expression of extracellular matrix proteins was estimated by determining the levels of their mRNAs using the real-time polymerase chain reaction. Mineralized nodule formation and calcium content in mineralized nodules were remarkably suppressed by nicotine on days 10 and 14 of culture, respectively. ALPase activity as well as type I collagen and osteopontin expression also decreased in the presence of nicotine after 5, 10, and 14 days of culture, respectively. By contrast, the amount of bone sialoprotein increased during 14 days of culture with nicotine. These results suggest that nicotine suppresses osteogenesis through a decrease in ALPase and type I collagen production by osteoblasts.

Impact of smoking on the clinical, microbiological and immunological parameters of adult patients with periodontitis

OBJECTIVES

The aim of the current study was to assess the impact of smoking on the clinical indices, the humoral immune response and the detection frequency of putative periodontal pathogens in patients with periodontitis cross-sectionally and following therapy.

MATERIAL AND METHODS

Clinical measurements, subgingival plaque samples, gingival crevicular fluid (GCF) and sera were collected from 40 untreated patients with moderate-to-advanced chronic periodontitis before and after treatment over a period of 6 months. The treatment consisted of the initial therapy of scaling and root planing. Smoking status was self-reported and was confirmed by cotinine enzyme inhibition assay (CEIA). Whole-mouth clinical measurements were recorded with a manual periodontal probe at baseline (BAS) and at 6 months (RAS). Selected-site analyses were performed on the deepest site in each quadrant before and after therapy and clinical indices were recorded with an electronic pressure-sensitive probe. GCF sample volume was quantified using the Periotron 6000. Polymerase chain reaction (PCR) was utilized to determine the presence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Prevotella intermedia, Treponema denticola and Tanerella forsythensis in subgingival plaque. Enzyme-linked immunosorbent assay examined the systemic antibody titres to these bacteria, and thiocyanate disassociation determined the antibody avidity to these organisms.

RESULTS

At baseline, smokers showed significantly less gingival inflammation and lower GCF volume compared with non-smokers. After treatment, a compromised clinical outcome was noted for smokers in terms of pocket depth reduction and gain in attachment levels. No significant differences in the detection of putative periodontal pathogens in subgingival plaque existed between smokers and non-smokers. A consistent trend was noted in that smokers had lower sera immunoglobulin G antibody titres to these organisms before and after treatment (statistically significant for A. actinomycetemcomitans). This pattern was less clear when antibody avidities were considered, revealing only small differences, if any, between the two groups of patients.

CONCLUSION

Current data indicate that smokers with periodontal disease have a suppressed inflammatory response, a significantly less favourable clinical outcome and seem to have an altered host antibody response to antigenic challenge than non-smokers. In contrast, the subgingival microflora of smokers appears similar to that of non-smokers.

Influence of Nicotine and Cotinine on Epithelial Colonization by Periodontopathogens

BACKGROUND

Since smoking is an established risk factor for the development of periodontitis, the present study investigated whether nicotine and cotinine can make epithelial cells more prone to colonization by periodontopathogens.

METHODS

Primary epithelial cell mono-layers were inoculated with nicotine and cotinine prior to adhesion experiments with Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. The number of bacteria associated with cells inoculated or not with nicotine or cotinine were assessed by an indirect culture viability assay. The same experimental set-up was used for assessing HeLa cells exposed to cigarette smoke extract (CSE).

RESULTS

Primary epithelial cells inoculated with concentrations of nicotine and cotinine, found in smokers and non smokers, did not show significant differences (P>0.05) in colonization susceptibility to A. actinomycetemcomitans. When these concentrations were increased to 1 mg/ml, a significant (P<0.05) and species-specific effect of the colonization susceptibility of epithelial cells was observed: It increased for A. actinomycetemcomitans, while it decreased for P. gingivalis. For both species the effects were more pronounced for nicotine, although this was not statistically significant. The change in colonization susceptibility did not result from alterations of the bacterial viability due to nicotine or cotinine. Treatment of HeLa cells with CSE also led to a species-specific variation in colonization tendency; i.e., increased for A. actinomycetemcomitans (P<0.05), but not for P. gingivalis.

CONCLUSIONS

The susceptibility of epithelial cells to become colonized by either A. actinomycetemcomitans or P. gingivalis could be altered by nicotine, cotinine, or CSE in a time-dependent, species-specific manner. Whether these findings that support the hypothesis of an increased patient susceptibility for bacterial adhesion to epithelial cells in smokers are clinically relevant remains to be proven.

Molecular analysis of human oral microbiota

OBJECTIVES

The application of molecular, mainly 16S ribosomal RNA (rRNA)-based approaches enables researchers to bypass the cultivation step and has proven its usefulness in studying the microbial composition in a variety of ecosystems, including the human oral cavity. In this mini-review, we describe the impact of these culture-independent approaches on our knowledge of the ecology of the human oral cavity and provide directions for future studies that should emphasize the role of specific strains, species and groups of microbes in periodontal disease.

MATERIALS AND METHODS

Recent findings are summarized to elucidate the relationship between periodontal disease and human oral microbiota, including as-yet-to-be-cultured organisms.

RESULTS

The real-time polymerase chain reaction (PCR) method was developed to detect and quantify periodontopathic bacteria, such as Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis (formerly Bacteroides forsythus) and Treponema denticola. The checkerboard DNA-DNA hybridization technique allowed enumeration of large numbers of species in very large numbers of samples. 16S rRNA gene clone library analysis revealed the diversity of human oral microbiota and the existence of as-yet-to-be-cultured organisms that are presumed periodontal pathogens. In addition, terminal restriction fragment length polymorphism (T-RFLP) analysis was applied for assessment of diversity of human oral microbiota.

CONCLUSION

Culture-independent approaches are useful for studying the microbial ecology in the human oral cavity and should be useful in the future to elucidate the etiology of periodontal disease.

Effect of khat chewing on 14 selected periodontal bacteria in sub- and supragingival plaque of a young male population

BACKGROUND/AIMS

The habit of chewing khat (Catha edulis) for its amphetamine-like effects is highly prevalent in Yemen and east Africa, and has expanded to Western countries. The purpose of this study was to estimate and compare the prevalence and levels of 14 periodontal bacteria in gingival plaque of khat chewers and khat nonchewers, as well as of khat chewing sides and khat nonchewing sides.

METHODS

A total of 408 sub- and supragingival plaque samples were collected from 51 young males (29 khat chewers and 22 khat nonchewers; age range 19-28 years) and analyzed using whole genomic DNA probes and checkerboard DNA-DNA hybridization. Clinical parameters were recorded for all teeth at six sites per tooth.

RESULTS

Streptococcus intermedius and Veillonella parvula were significantly more prevalent in the subgingival plaque of chewers, which also showed significantly higher levels of V. parvula and Eikenella corrodens. Similar results were found for the subgingival plaque of the chewing sides compared to the nonchewing sides. However, there was a significantly higher prevalence and higher levels of Tannerella forsythia in the subgingival plaque of the nonchewing sides. No significant differences were observed for the supragingival plaque between the two study groups. There was a significantly lower prevalence of Capnocytophaga gingivalis and Fusobacterium nucleatum in the khat chewing sides, and higher levels of V. parvula and Actinomyces israelii.

CONCLUSION

The data suggest that khat chewing induces a microbial profile that is not incompatible with gingival health.

Tobacco smoking and periodontal microflora in a Saudi Arabian population

OBJECTIVES

To explore the subgingival periodontal microflora in a Saudi Arabian population with a special focus on its relationship with various smoking habits.

MATERIAL AND METHODS

A total of 198 individuals in the age range 17-60 years were included in the study. 29% were water-pipe smokers, 18% cigarette smokers, 13% smokers of both water pipe and cigarettes (mixed smokers) and 40% non-smokers. For each individual, a subgingival plaque sample from the deepest site in each quadrant was obtained. The checkerboard DNA-DNA hybridization technology was used to determine the presence of Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Tannerella forsythensis, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Treponoma denticola, Peptostreptococcus micros, Campylobacter rectus, Eikenella corrodens, Selenomonas noxia and Streptococcus intermedius. Two cut-off levels for detection were used, score 1(10(5) bacteria) and score 3 (10(6) bacteria).

RESULTS

The prevalence of individuals positive for the different microorganisms at score 1 cut-off varied from 7% to 95%. At score 3 cut-off the prevalence varied from 0% to 30%. The depth of sample site was a key factor for detection. When the depth of sample site was taken into account, no statistically significant differences were observed between cigarette smokers, water-pipe smokers, and non-smokers with regard to occurrence of the microorganisms studied.

CONCLUSIONS

No major differences were observed between cigarette smokers, water-pipe smokers, and non-smokers regarding the occurrence of the periodontal microorganisms studied suggesting that this portion of the subgingival periodontal microflora is independent of tobacco smoking.

Experimental gingivitis in cigarette smokers: a clinical and microbiological study

OBJECTIVE

To assess clinical and microbiological changes during experimental gingivitis in cigarette smokers and non-smokers.

MATERIAL AND METHODS

Eleven current smokers (>/=5 years) and 11 (never-) non-smokers periodontally healthy or with gingivitis (PPD</=4 mm) were included. According to the original model (Löe et al. 1965), an experimental 3-week plaque accumulation period resulting in experimental gingivitis and a subsequent 2-week period of optimal plaque control were performed. Subgingival plaque samples were collected at days 0, 21 and 35 from one site per quadrant, pooled and analysed using checkerboard DNA-DNA hybridization.

RESULTS

Smokers {mean age: 24.7+/-2.2 [standard deviation (SD)] years, range 21-28 years} had a mean lifetime cigarette exposure of 6.4+/-2.8 (SD) pack-years, while non-smokers presented with a mean age of 23.1+/-2.2 (SD) years (range 21-29 years). Between days 0, 21 and 35, no statistically significant differences in mean Plaque and mean Gingival Index scores were observed between smokers and non-smokers. In both smokers and non-smokers, mean total DNA probe counts did not significantly differ nor increase between days 0 and 21. Also, between days 21 and 35 they did not significantly differ nor decrease. This was also true for the various proportions of bacterial complexes.

CONCLUSION

Both current smokers and (never-) non-smokers reacted to experimental plaque accumulation with gingival inflammation. Periodontal and microbiological parameters assessed in current cigarette smokers did not significantly differ from those in non-smokers during an identical period of experimental plaque accumulation. Hence, the early host response to the bacterial challenge appears to be of similar magnitude and timing in both groups.

Augmented transforming growth factor-beta1 in gingival crevicular fluid of smokers with chronic periodontitis

BACKGROUND

Patients who smoke are at increased risk for chronic periodontitis (CP). Also, CP patients who smoke exhibit significantly less reduction of probing depths and gains in clinical attachment compared to non-smokers following periodontal therapy. Several studies suggest that the effects of smoking on the host response may be paramount in regulating the basal systemic inflammatory status and therapeutic outcomes in this cohort. Growth factors, specifically transforming growth factor beta1 (TGF-beta1), are critical in regulating the wound healing response by controlling cell division, differentiation, and motility. The hypothesis to be tested was that gingival crevicular fluid (GCF) TGF-beta1 production was altered in smokers compared to non-smokers with CP.

METHODS

GCF was collected from smokers and non-smokers with CP, both at baseline and 1 to 2 weeks after initial therapy. GCF volume was determined using an electronic device and TGF-beta1 concentration was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Smokers exhibited a higher mean concentration of GCF TGF-beta1 at baseline compared to non-smokers (P = 0.03). After initial therapy, smokers exhibited significantly less reduction in mean GCF volume compared to non-smokers (P = 0.04).

CONCLUSIONS

Augmented constitutive production of GCF TGF-beta1 in smokers may explain the clinical appearance of fibrotic gingival tissue exhibited by this patient cohort. A diminished reduction in GCF volume in smokers following root instrumentation suggests a chronic inflammatory status in conjunction with an ineffective host response. These findings support the concept that smokers with CP display an altered local inflammatory response after initial therapy, perhaps symptomatic of colonization by residual periodontal pathogens.

Clinical Response of Azithromycin as an Adjunct to Non-Surgical Periodontal Therapy in Smokers

BACKGROUND

Antibiotic therapy can be used in very specific periodontal treatment situations such as in refractory cases of periodontal disease found to be more prevalent in smokers. This study was designed to determine the efficacy of azithromycin (AZM) when combined with scaling and root planing (SRP) for the treatment of moderate to severe chronic periodontitis in smokers.

METHODS

Thirty-one subjects were enrolled into a 6-month randomized, single-masked trial to evaluate clinical, microbial (using benzoyl- DL-arginine naphthylamine [BANA] assay), and gingival crevicular fluid (GCF) pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) levels in response to SRP alone or SRP + AZM. At baseline, patients who smoked > or =1 pack per day of cigarettes who presented with at least five sites with probing depths (PD) of > or =5 mm with bleeding on probing (BOP) were randomized into the test or control groups. At baseline and 3 and 6 months, clinical measurements (probing depth [PD], clinical attachment loss [CAL], and bleeding on probing [BOP]) were performed. GCF bone marker assessment (Ctelopeptide [ICTP] as well as BANA test analyses) were performed at baseline, 14 days, and 3 and 6 months.

RESULTS

The results demonstrated that both groups displayed clinical improvements in PD and CAL that were sustained for 6 months. Using a subject-based analysis, patients treated with SRP + AZM showed enhanced reductions in PD and gains in CAL at moderate (4 to 6 mm) and deep sites (>6 mm) (P <0.05). Furthermore, SRP + AZM resulted in greater reductions in BANA levels compared to SRP alone (P <0.05) while rebounds in BANA levels were noted in control group at the 6-month evaluation. No statistically significant differences between groups on mean BOP and ICTP levels during the course of the study were noted.

CONCLUSIONS

The utilization of AZM in combination with SRP improves the efficacy of non-surgical periodontal therapy in reducing probing depth and improving attachment levels in smokers with moderate to advanced attachment loss.

Use of checkerboard DNA-DNA hybridization to study complex microbial ecosystems

It has been difficult to conduct large scale studies of microbiologically complex ecosystems using conventional microbiological techniques. Molecular identification techniques in new probe-target formats, such as checkerboard DNA-DNA hybridization, permit enumeration of large numbers of species in very large numbers of samples. Digoxigenin-labeled whole genomic probes to 40 common subgingival species were tested in a checkerboard hydridization format. Chemifluorescent signals resulting from the hybridization reactions were quantified using a Fluorimager and used to evaluate sensitivity and specificity of the probes. Sensitivity of the DNA probes was adjusted to detect 10(4) cells. In all, 93.5% of potential cross-reactions to 80 cultivable species exhibited signals <5% of that detected for the homologous probe signal. Competitive hybridization and probes prepared by subtraction hybridization and polymerase chain reaction were effective in minimizing cross-reactions for closely related taxa. To demonstrate utility, the technique was used to evaluate 8887 subgingival plaque samples from 79 periodontally healthy and 272 chronic periodontitis subjects and 8126 samples from 166 subjects taken prior to and after periodontal therapy. Significant differences were detected for many taxa for mean counts, proportion of total sample, and percentage of sites colonized between samples from periodontally healthy and periodontitis subjects. Further, significant reductions were observed post therapy for many subgingival species including periodontal pathogens. DNA probes used in the checkerboard DNA-DNA format provide a useful tool for the enumeration of bacterial species in microbiologically complex systems.

Mechanisms of action of environmental factors--tobacco smoking

AIM

To review the potential biological mechanisms underlying the effects of tobacco smoking on periodontitis.

MAIN FINDINGS

Smoking has major effects on the host response, but there are also a number of studies that show some microbiological differences between smokers and non-smokers. Smoking has a long-term chronic effect on many important aspects of the inflammatory and immune responses. Histological studies have shown alterations in the vasculature of the periodontal tissues in smokers. Smoking induces a significant systemic neutrophilia, but neutrophil transmigration across the periodontal microvasculature is impeded. The suppression of neutrophil cell spreading, chemokinesis, chemotaxis and phagocytosis have been described. Protease release from neutrophils may be an important mechanism in tissue destruction. Tobacco smoke has been found to affect both cell-mediated immunity and humoral immunity. Research on gingival crevicular fluid has demonstrated that there are lower levels of cytokines, enzymes and possibly polymorphonuclear cells in smokers. In vitro studies have shown detrimental effects of nicotine and some other tobacco compounds on fibroblast function, including fibroblast proliferation, adhesion to root surfaces and cytotoxicity.

CONCLUSION

Tobacco smoking has widespread systemic effects, many of which may provide mechanisms for the increased susceptibility to periodontitis and the poorer response to treatment.

Evaluation of the relationship between smoking during pregnancy and subgingival microbiota

BACKGROUND

Numerous studies have shown that smoking negatively affects periodontal health. Hormonal changes, which occur during pregnancy have also been reported to have adverse effects on the periodontal tissues or indirectly through alterations in the subgingival bacterial flora. At present, no knowledge exists concerning possible effects of smoking on the composition of subgingival plaque in pregnancy. The purpose of the present study was to evaluate the effects of smoking during pregnancy on the subgingival plaque bacteria most commonly associated with periodontal disease.

METHODS

A total number of 181 women were examined within 72 h post-partum. Smoking status was recorded by means of a self-reported questionnaire and the study population was divided into three groups; non-smokers, light smokers, and heavy smokers. In each woman, two subgingival plaque samples were obtained from mesio- or disto-buccal aspect of randomly selected one molar and one incisor tooth by sterile paperpoints. Clinical periodontal recordings comprising presence of dental plaque, bleeding on probing (BOP), and probing pocket depth (PPD) were performed at six sites per each tooth at all teeth. Plaque samples were analysed by checkerboard DNA-DNA hybridization with respect to 12 bacterial species. In all analyses, the individual subject was the computational unit. Thus, mean values for all clinical parameters were calculated and bacterial scores from each individual sample were averaged. Statistical methods included chi2 test, Kruskal-Wallis test and Mann-Whitney U-test.

RESULTS

Mean ages were similar in the study groups. Plaque, BOP and PPD recordings were lower in the heavy-smoker group, but the differences were not statistically significant (p>0.05). The detection rates and bacterial loads of the specific subgingival bacteria exhibited no significant differences between the groups. No correlation could be found between smoking status and detection rates and bacterial loads of various bacterial species.

CONCLUSION

The present findings suggest that smoking during pregnancy does not have a significant effect on the composition of subgingival plaque bacteria.

Methods of detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in periodontal microbiology, with special emphasis on advanced molecular techniques: a review

BACKGROUND

Certain specific bacterial species from the subgingival biofilm have demonstrated aetiological relevance in the initiation and progression of periodontitis. Among all the bacteria studied, three have shown the highest association with destructive periodontal diseases: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Tannerella forsythensis (Tf). Therefore, the relevance of having accurate microbiological diagnostic techniques for their identification and quantification is clearly justified.

AIM

To evaluate critically all scientific information on the currently available microbial diagnostic techniques aimed for the identification and quantification of Aa, Pg and Tf.

SUMMARY

Bacterial culturing has been the reference diagnostic technique for many years and, in fact, most of our current knowledge on periodontal microbiology derives from cultural data. However, the advent of new microbial diagnostics, mostly based on immune and molecular technologies, has not only highlighted some of the shortcomings of cultural techniques but has also allowed their introduction as easy and available adjunct diagnostic tools to be used in clinical research and practice. These technologies, mostly polymerase chain reaction (PCR), represent a field of continuous development; however, we still lack the ideal diagnostic to study the subgingival microflora. Qualitative PCR is still hampered by the limited information provided. Quantitative PCR is still in development; however, the promising early results reported are still hampered by the high cost and the equipment necessary for the processing.

CONCLUSION

Quantitative PCR technology may have a major role in the near future as an adjunctive diagnostic tool in both epidemiological and clinical studies in periodontology. However, culture techniques still hold some inherent capabilities, which makes this diagnostic tool the current reference standard in periodontal microbiology.

Familial correlations, segregation analysis, and nongenetic correlates of soy isoflavone-metabolizing phenotypes

Particular intestinal bacteria metabolize the soy isoflavone daidzein to equol and O-desmethylangolensin (O-DMA), metabolites that can be identified in urine. Individuals that harbor bacteria capable of producing equol or O-DMA are known as equol producers (approximately 30%-50% of the population) and O-DMA producers (approximately 80%-90% of the population), respectively. The equol-producer phenotype has been associated with sex hormone-related outcomes in several studies. However, the bacteria responsible for these phenotypes have not yet been identified and factors that influence the manifestation of these phenotypes are not well understood. To evaluate familial clustering of and nongenetic factors associated with these phenotypes, 410 individuals from 112 families participated in phenotyping (3-day soy challenge and Day 4 spot urine collection). In segregation analyses of the equol-producer phenotype, the Mendelian dominant model provided the most parsimonious fit to the data, suggesting that the pattern of inheritance of the equol-producer phenotype is consistent with an autosomal dominant trait. This phenotype was positively associated with education (p trend = 0.01), but not with sex, smoking, or several dietary factors. Results of the segregation analyses of the O-DMA-producer phenotype were inconclusive; no other models provided a more parsimonious fit to the data than the general model. This phenotype was inversely associated with age in a nonlinear model (p = 0.01), positively associated with age- and sex-adjusted height (odds ratio [OR] 10-cm increase = 0.38, 95% confidence interval [CI] = 0.15, 0.95) and body mass index (kg/m(2)) (OR = 0.91, 95% CI = 0.85, 0.96), but not with sex, education, smoking, or several dietary factors. These results suggest the equol-producer phenotype may be under some degree of genetic control and that there are likely other environmental factors not evaluated in the present analysis that contribute to both of these phenotypes. These results provide a foundation for further work to refine our understanding of heritable and environmental determinants of daidzein-metabolizing phenotypes.

Cytokine profile in gingival crevicular fluid of aggressive periodontitis: influence of smoking and stress

BACKGROUND

Cigarette smoking and stress are considered risk factors that have been associated with periodontal disease progression. Conflicting results have been reported concerning the direct influence of smoking on the subgingival microbiota of periodontitis patients. Cytokine production may also be influenced by smoking and stress leading to an imbalance that disturbs the host-parasite relationship.

AIM

The objective of the present study was to evaluate the influence of cigarette smoking on the gingival crevicular fluid (GCF) levels of interleukin (IL)-1beta, IL-4, IL-6 and IL-8 in aggressive or early onset periodontitis (EOP) patients and in healthy controls (H), psychosocial stress being considered as modifying factor.

MATERIAL AND METHODS

Sixty-five EOP and 35 periodontally healthy individuals participated in this cross-sectional study. All the participants were interviewed about their smoking habits and their stressful social events. Clinical examination included the assessment of plaque index (PI), bleeding on probing (BOP), clinical attachment level (CAL) and probing pocket depth (PPD). GCF was collected using durapore strips, from four sites per patient, randomly selected in each quadrant. The total amounts of IL-1beta, IL-4, IL-6 and IL-8 were measured in a total of 400 samples using commercially available enzyme-linked immunosorbent assays.

RESULTS

All clinical parameters were significantly higher in the EOP group compared to the H group. There were no significant differences between EOP smokers and EOP non-smokers with regard to plaque accumulation, CAL and PPD of the sampling sites, whereas mean CAL and PPD of the diseased sites were greater in EOP smokers than in EOP non-smokers. In addition, EOP smokers seemed to have significantly less BOP and greater bone loss compared to EOP non-smokers. Significant interactions between "EOP" and "smoking" were present for total amounts of IL-1beta and IL-4. IL-1beta, IL-6 and IL-8 showed significant main effects with healthy smokers and healthy non-smokers, respectively. For IL-8, stress presented a statistically significant interaction with smoking status and EOP (F=4.742, p=0.030). More specifically EOP smokers were statistically affected by stress.

CONCLUSIONS

Smoking influences host-related factors including cytokine network. The relative importance of smoking and stress-related alterations and their precise mode of action in increasing the risk of aggressive periodontitis remains to be elucidated.

Subgingival microbiota of chilean patients with chronic periodontitis

BACKGROUND

An association between race/ethnicity and the composition of the subgingival microbiota has been found in chronic periodontitis. A study was undertaken to determine the characteristics of the subgingival microbiota of chronic periodontitis in Chileans residing in Santiago.

METHODS

Twenty-six subjects (mean age 45 +/- 7 years) with chronic periodontitis, mean probing depth (PD) 2.63 +/- 0.5 mm, mean attachment level (AL) 3.70 +/- 0.77 mm, and without a history of periodontal therapy were selected. Measurements of PD, AL, bleeding on probing, and plaque accumulation were recorded at six sites per tooth. Subgingival plaque samples were taken from the mesial aspect of every tooth and evaluated for the presence, levels, and proportions of 40 bacterial taxa using whole genomic DNA probes and checkerboard DNA-DNA hybridization. The microbial data of the Chileans were compared with data from 115 chronic periodontitis patients from Boston, Massachusetts. Since several clinical and demographic parameters differed between the two populations, significance of differences for each species was determined using analysis of covariance, adjusting for age, plaque level, mean PD, gender, and smoking status.

RESULTS

Each of the individual test species was present in at least 25 of the 26 subjects, and 12 subjects (46.1%) harbored all 40 test species. With the exception of Prevotella intermedia, all test species colonized more than 75% of sites, and 25 species colonized > or = 90% of sites including the co-colonizing species of advanced periodontal lesions, termed the red complex, composed of the three species Porphyromonas gingivalis, Tannerella forsythensis (formerly Bacteroides forsythus), and Treponema denticola as well as Fusobacterium nucleatum subspecies, Campylobacter rectus, Peptostreptococcus micros, and Treponerma socranskii. Sixteen of the 40 species differed significantly between Chilean and U.S. subjects. Red, yellow, and other complexes were significantly higher in the Chileans, while the Actinomyces were higher in the U.S. subjects.

CONCLUSIONS

The composition of the subgingival plaque differs among different subject populations. Thus, care should be taken when extrapolating the findings of one study to different ethnic groups.

Locally delivered doxycycline improves the healing following non-surgical periodontal therapy in smokers

OBJECTIVE

The outcome of non-surgical periodontal therapy is known to be inferior in smokers compared to non-smokers. In the present study, the question was asked whether such a difference in healing response may be less evident following adjunctive use of locally delivered controlled-release doxycycline.

METHODS

One hundred and three patients (42 smokers, 61 non-smokers), each having at least eight periodontal sites with PPD (probing pocket depth) > or =5 mm, were following stratification for smoking randomly assigned to two different treatment protocols; non-surgical scaling/root planing (Control) or ultrasonic instrumentation+application of a 8.5% w/w doxycycline gel (Atridox trade mark ) (Test). Instructions in oral hygiene were given to all patients. Clinical examinations of plaque, PPD, clinical attachment level (CAL) and bleeding following pocket probing were performed at baseline and after 3 months. Primary efficacy endpoints were changes in PPD and CAL. Patient mean values were calculated as basis for statistical analysis (multiple regression analyses).

RESULTS

The baseline examination revealed no significant difference in mean PPD between treatment groups or between smokers and non-smokers (mean PPD 5.7-5.9 mm). The mean PPD reduction in the control group at 3-month was 1.1 mm (SD=0.45) for smokers and 1.5 mm (0.67) for non-smokers. In the test group the PPD reduction was 1.4 mm (0.60) and 1.6 mm (0.45) for smokers and non-smokers, respectively. The mean CAL gain for smokers and non-smokers amounted to 0.5 mm (0.56) and 0.8 mm (0.71), respectively, in the control group, and to 0.8 mm (0.72) and 0.9 mm (0.82), respectively, in the test group. Multiple regression analysis revealed that smoking and initial PPD negatively influenced the treatment outcome in terms of PPD reduction and CAL gain, while the use of doxycycline had a significant positive effect.

CONCLUSION

Locally applied controlled-release doxycycline gel may partly counteract the negative effect of smoking on periodontal healing following non-surgical therapy.

Inhibition of osteogenesis in vitro by a cigarette smoke-associated hydrocarbon combined with Porphyromonas gingivalis lipopolysaccharide: reversal by resveratrol

BACKGROUND

Smoking and infection with Gram-negative bacterial pathogens are risk factors for alveolar bone loss. The aims of this study were: 1) to examine the combined effects of an aryl hydrocarbon, benzo[a]pyrene (BaP), that is concentrated in cigarette smoke, and lipopolysaccharide (LPS) extracted from Porphyromonas gingivalis on osteogenesis in a rat bone marrow cell (RBMC) model of osteogenesis; and 2) to determine whether resveratrol (Res), an aryl hydrocarbon receptor antagonist, could reverse the putative inhibitory effects of BaP + LPS on osteogenesis.

METHODS

LPS of P. gingivalis strain 2561 was introduced in various concentrations to the RBMC in 96-well plates and kept in culture for 8 to 12 days. The same protocol was used for studying BaP and LPS + BaP combinations. Following the incubation periods, parameters of osteogenesis were measured, including formation of mineralized bone nodules, alkaline phosphatase activity, and total cell protein. Transcription of the pro-inflammatory cytokine interleukin (IL)-1beta in the cultures was determined by reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Bone nodule formation generally decreased significantly with increasing LPS concentrations (P<0.05), whereas total cell protein decreased only slightly (P>0.05). BaP in previously high concentrations alone also caused a significant dose-dependent decrease in bone nodule formation (P<0.05) but when half maximal doses were used, significant decreases were most often seen when LPS was added. Hence, in combination, the inhibitory effects of LPS + BaP on osteogenesis were additive, inhibiting bone nodule formation up to 9-fold. Resveratrol partially reversed the inhibitory effects of low concentrations of LPS alone, and completely reversed the inhibition of nodule formation when low concentrations of LPS were combined with BaP. IL-1beta expression generally fluctuated inversely to the inhibitory activity of LPS, LPS + BaP, and LPS + BaP + Res combinations.

CONCLUSIONS

Smoke-derived aryl hydrocarbons and bacterial LPS may act additively to inhibit bone formation. The findings may explain, in part, why net periodontal bone loss is greater and bone healing is less successful in smokers than non-smokers with periodontal infections. Reversal of the inhibitory effects in vitro by resveratrol suggests that this phytoalexin should be studied further for its potential therapeutic value, given its aryl hydrocarbon receptor antagonism and apparent anti-inflammatory activity.

The influence of tobacco smoking on the onset of periodontitis in young persons

This paper reviews the evidence for cigarette smoking as a risk factor for the development of severe destructive periodontal disease in young adults. A high prevalence of cigarette smoking has been identified among young individuals with aggressive periodontitis and tobacco usage increases the risk of periodontal destruction most significantly in young populations. The effect appears to be dose related and is independent of levels of plaque accumulation. Young smokers have more alveolar bone loss and attachment loss than non smoking equivalents. Prolonged and heavy smoking can reduce gingival bleeding and therefore mask the clinical marker of bleeding on probing often used by dentists to monitor periodontal health. This has implications for potential misdiagnosis and failure to detect periodontitis at an early stage. Nicotine metabolites concentrate in the periodontal tissues and can have local effects as well as the potential to affect the systemic host response. Dentists are well placed to assess the smoking status of their young patients and have a role to play in the delivery of smoking cessation advice especially as it pertains to periodontal health. In this way the dental profession can also make a significant contribution to the general health and well being of our youth and future generations.

Effect of Periodontal Therapy in Smokers and Non-Smokers With Advanced Periodontal Disease: Results After Maintenance Therapy for a Minimum of 5 Years

BACKGROUND

Longitudinal clinical studies show smoking is a risk factor for periodontal disease progression. It has also been documented that smoking impairs healing after periodontal therapy. However, the longitudinal effect of smoking on treatment results in patients who undergo long-term maintenance therapy has not been extensively investigated. This study clinically and radiographically compared smoking and non-smoking patients who had been treated for advanced periodontal disease and who received maintenance therapy for a minimum of 5 years.

METHODS

Twenty-nine patients were selected over a 6-month period when they presented for a regularly scheduled visit in a private office. Patients were selected on the basis of initially having lost 50% of bone support on 50% of their teeth; had received follow-up therapy for at least 5 years; were compliant at 75% of the appointments; and had plaque scores < 20% in 75% of the visits. All patients had received non-surgical and surgical therapy as required for pocket elimination. Fourteen were active smokers during the entire maintenance period. Clinical measurements of probing depths and presence of plaque and gingivitis and a new set of standardized radiographs were taken.

RESULTS

Smokers had higher mean radiographic bone loss values prior to treatment (7.52 +/- 1.39 versus 6.65 +/- 1.39) and at the final examination (7.32 +/- 1.42 versus 6.29 +/- 1.29) mean radiographic bone loss as well as initial, immediate post-therapy, and final percent of pockets > or = 6 mm (1.42% +/- 1.87% versus 0.60% +/- 1.11%). Differences were not statistically significant. Over 5 to 8 years, seven sites in four non-smokers and 11 sites in six smokers exhibited radiographic bone loss > or = 2 mm. One tooth in a non-smoker and three teeth in two smokers were lost. In a logistic regression analysis, smoking increased the odds ratio 10.7 times of having > or = 1 site with bone loss > or = 2 mm.

CONCLUSION

The present study on a small group of patients treated for advanced periodontal disease and well maintained over 5 to 8 years showed no statistically significant differences between smokers and non-smokers in clinical probing depth and radiographic bone loss measurements.

Effects of periodontitis and smoking on the microbiota of oral mucous membranes and saliva in systemically healthy subjects

BACKGROUND/AIM

To examine the differences in the proportions of 40 bacterial species in samples from eight oral soft-tissue surfaces and saliva in systemically healthy adult subjects with and without periodontitis and in smokers and nonsmokers.

METHODS

Saliva and microbial samples were taken from eight oral soft-tissue surfaces in 229 systemically healthy subjects stratified by periodontal and smoking status. Subjects included 84 periodontally healthy and 145 periodontitis individuals. Of these, there were 182 nonsmokers and 47 smokers. Soft-tissue samples were taken using a "buccal brush" and saliva was taken by expectoration. All samples were individually evaluated for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. The percentage of total DNA probe count was determined for each species at each sample location and averaged across subjects. The significance of differences among the proportions of the 40 test species at different sample locations was sought in these populations using the Kruskall-Wallis test and adjusted for multiple comparisons.

RESULTS

When stratified for periodontal status or smoking status, microbial profiles at most sites did not differ significantly. Generally, periodontal pathogens were found at higher levels on the soft tissues of periodontitis subjects than in periodontally healthy subjects, and at higher levels in smokers than nonsmokers. Few significant differences were found, although trends in the populations were noted.

CONCLUSIONS

Small differences in the proportions of bacterial species were observed on soft tissues and in saliva comparing periodontally healthy and periodontitis subjects. Somewhat greater differences between smokers and nonsmokers were found; however, these were not statistically significant.

Cigarette Smoking and the Periodontal Patient

Evidence from cross-sectional and case-control studies in various populations demonstrates that adult smokers are approximately three times as likely as non-smokers to have periodontitis. The association between smoking and attachment loss is even stronger when the definition of periodontitis is restricted to the most severely affected subjects. Smokers have a diminished response to periodontal therapy and show approximately half as much improvement in probing depths and clinical attachment levels following non-surgical and various surgical modalities of therapy. Implant failures in smokers are twice those of non-smokers, with a higher failure rate in the maxillary arch accounting for the majority of the difference. Tobacco-induced alterations in microbial and host factors contribute to these deleterious effects of smoking on the periodontium. In longitudinal studies, the rate of periodontal disease progression is increased in smokers, but decreases to that of a non-smoker following tobacco cessation. Likewise, recent non-smokers respond to periodontal therapy in a manner similar to patients who have never smoked. Data regarding the impact of smoking on periodontal status included in this review will be helpful to dental health professionals as they counsel their patients regarding tobacco use. The role of dental health professionals in tobacco cessation is discussed, including the use of the five A's: ask--identify tobacco users; advise--advise them to quit; assess--evaluate the patient's readiness to quit; assist--offer assistance in cessation; and arrange--follow up on the patient's cessation efforts. The addition of pharmacotherapy to behavioral therapy, including nicotine replacement therapy and bupropion, can increase cessation rates. The most popular form of nicotine replacement therapy is the patch, and its use has been shown to double cessation rates compared to behavioral therapy alone. Use of bupropion in combination with nicotine replacement therapy may be particularly helpful for heavy smokers or smokers who have experienced multiple failed attempts at cessation. The American Academy of Periodontology Parameters of Care include tobacco cessation as a part of periodontal therapy, and the 2000 Surgeon General's Report on Oral Health in America encourages dental professionals to become more active in tobacco cessation counseling. Doing so will have far-reaching positive effects on our patients' oral and general health.

Effect of smoking and periodontal treatment on the subgingival microflora

BACKGROUND

The effect of smoking on the prevalence of periodontal pathogens after periodontal treatment is still not clear. Some studies found no effect of the smoking status on the prevalence of periodontal pathogens after therapy, whereas others did. The aim of this retrospective study was to investigate the influence of smoking on the treatment of periodontitis and the composition of the subgingival microflora.

METHOD

The study included 59 periodontitis patients (mean age 41.5 years): 30 smokers and 29 nonsmokers. The treatment consisted of initial periodontal therapy and, if necessary, surgery and/or antibiotics. Clinical and microbiological data were obtained before and after treatment at the deepest site in each quadrant. A pooled sample was analysed for the presence of Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotalla intermedia (Pi), Bacteroides forsythus (Bf), Fusobacterium nucleatum (Fn) and Peptostreptococcus micros (Pm).

RESULTS

For smokers and nonsmokers a significant improvement of the clinical condition was found after treatment. A decrease could be assessed for bleeding on probing (smokers: 0.46; nonsmokers: 0.52) and probing pocket depth (PPD) (smokers: 1.64 mm; nonsmokers: 2.09 mm). Furthermore, both groups showed gain of attachment (smokers: 0.68 mm; nonsmokers: 1.46 mm). No significant difference in bleeding on probing and PPD reduction was found between smokers and nonsmokers. In contrast, nonsmokers showed significantly more gain of attachment than smokers. The microbiological results revealed no differences in the prevalence of the various bacteria between smokers and nonsmokers before treatment. After treatment in nonsmokers, a significant decrease was found in the prevalence of Aa (11-3), Pg (17-7), Pi (27-11), Bf (27-11), Fn (28-20) and Pm (27-17). In smokers, a significant decrease could be shown only for the prevalence of Pg (15-5).

CONCLUSIONS

Nonsmokers showed more gain of attachment and a greater decrease in the prevalence of periodontal bacteria as compared to smokers. The phenomenon that among smokers, more patients remain culture positive for periodontal pathogens after therapy, may contribute to the often observed unfavourable treatment results in smoker periodontitis patients.

Tobacco and oral diseases. Update on the evidence, with recommendations

It is well known that smoking contributes to the development of lung cancer and cardiovascular disease, and there is weighty evidence that it has a considerable influence on oral health. Smoking has many negative effects on the mouth, including staining of teeth and dental restorations, reduction of the ability to smell and taste, and the development of oral diseases such as smoker's palate, smoker's melanosis, coated tongue, and, possibly, oral candidosis and dental caries, periodontal disease, implant failure, oral precancer and cancer. From a qualitative point of view the latter is obviously the most serious tobacco-related effect in the mouth. Quantitatively, however, importance has been attached to periodontitis, which affects a large proportion of the population, and during recent years more attention has been given to implant survival rates. Dentists have an important role to play in preventing the harmful effects of smoking in the mouth, and consequently smoking counselling should be as much a part of the dentist's job as plaque control and dietary advice.

Prevalence and severity of periodontal disease at mandibular molar teeth in smokers with regular oral hygiene habits

BACKGROUND

Smoking appears to be detrimental to health because it has been associated with several diseases including cancer and cardiovascular diseases. Smoking also appears to be a major environmental factor associated with periodontal disease progression. The objective of this study was to evaluate the prevalence and severity of periodontal destruction as influenced by smoking in a Thai population.

METHODS

Gingival health and periodontal conditions at mandibular molar furcation sites in 120 Thai dental patients (60 smokers and 60 never-smokers, age range 31 to 60 years) with generally high oral hygiene standards and regular dental care habits were evaluated.

RESULTS

Smokers exhibited more frequent and severe mandibular molar periodontal destruction than never-smokers. The prevalence and severity of gingival recession, periodontal pocket formation, clinical attachment loss, furcation involvement, and tooth mobility were significantly increased in smokers compared to never-smokers. Seventy-three percent of the smokers exhibited furcation involvement in contrast to only 20% of the never-smokers.

CONCLUSIONS

The results of this study suggest that smoking appears to be a major environmental factor associated with accelerated periodontal destruction in adult smokers with generally high oral hygiene standards and regular dental care habits in a Thai population.