Potential associations between chronic respiratory disease and periodontal disease: analysis of National Health and Nutrition Examination Survey III

Recovery of periodontopathogenic bacteria from embalmed human cadavers

There is recent interest in recovery of periodontopathogenic bacteria from arterial and bronchial tissues to identify a link between periodontal and cardiovascular or pulmonary diseases. This interest could provide a useful clinical correlation exercise for gross anatomy. Our objective was to perform a feasibility study to determine whether these bacteria could be recovered from two sites within eight (4 dentate, 4 edentulous) human embalmed cadavers from an anatomical dissection laboratory. Bacterial samples were collected from the right coronary artery and the right superior secondary bronchus and assayed for the presence and concentrations of the DNA of A. actinomycetemcomitans, E. corrodens, C. rectus, P. intermedia, P. gingivalis, B. forsythus, T. denticola, and F. nucleatum. Frequencies were compared using a Kruskal-Wallis H-test. Correlations between the presence of teeth, bacterial species, and site were determined by a Spearman's rho correlation test. A. actinomycetemcomitans and B. forsythus frequencies were different between the sites in edentulous subjects (P <0.05); the frequency of B. forsythus was different in dentate and edentulous subjects at the bronchus site (P <0.05). Numerous significant correlations were identified between strains of bacteria, site, and presence of teeth. Thus, it is possible for the DNA of periodontopathogenic bacteria to be recovered from human embalmed cadavers. Collection and identification of these bacteria from these cadavers could be a useful clinical correlation exercise for dental students in a gross anatomy class.

Oral Health and Care in the Intensive Care Unit: State of the Science

Oral health is influenced by oral microbial flora, which are concentrated in dental plaque. Dental plaque provides a microhabitat for organisms and an opportunity for adherence of the organisms to either the tooth surface or other microorganisms. In critically ill patients, potential pathogens can be cultured from the oral cavity. These microorganisms in the mouth can translocate and colonize the lung, resulting in ventilator-associated pneumonia. The importance of oral care in the intensive care unit has been noted in the literature, but little research is available on mechanical or pharmacological approaches to reducing oral microbial flora via oral care in critically ill adults. Most research in oral care has been directed toward patients’ comfort; the microbiological and physiological effects of tooth brushing in the intensive care unit have not been reported. Although 2 studies indicated reductions in rates of ventilator-associated pneumonia in cardiac surgery patients who received chlorhexidine before intubation and postoperatively, the effects of chlorhexidine in reducing ventilator-associated pneumonia in other populations of critically ill patients or its effect when treatment with the agent initiated after intubation have not been reported. In addition, no evaluation of the effectiveness of pharmacological and mechanical interventions relative to each other or in combination has been published. Additional studies are needed to develop and test best practices for oral care in critically ill patients.

Associations Between Periodontal Disease and Risk for Nosocomial Bacterial Pneumonia and Chronic Obstructive Pulmonary Disease. A Systematic Review

BACKGROUND

Several recent studies provide evidence that the oral cavity may influence the initiation and/or the progression of lung diseases such as pneumonia and chronic obstructive pulmonary disease (COPD).

RATIONALE

Studies have shown that poor oral hygiene and periodontal disease may foster colonization of the oropharyngeal region by respiratory pathogens, particularly in hospital or nursing home patients. If aspirated, these pathogens can cause pneumonia, one of the most common respiratory infections, especially in institutionalized subjects. Other cross-sectional epidemiologic studies point to an association between periodontal disease and COPD. This systematic review examines the literature to determine if interventions that improve oral hygiene reduce the rate of pneumonia in high-risk populations.

FOCUSED QUESTION

Do periodontal diseases or other indicators of poor oral health influence the initiation/progression of pneumonia or other lung diseases?

SEARCH PROTOCOL

MEDLINE, pre-MEDLINE, MEDLINE Daily Update, and the Cochrane Controlled Trials Register were searched to identify published studies that related variables associated with pneumonia and other lung disease to periodontal disease. Searches were performed for articles published in English from 1966 through March 2002.

INCLUSION CRITERIA

Randomized controlled clinical trials (RCTs), longitudinal, cohort, and case-control studies were included. Study populations included patients with any form of pneumonia or chronic obstructive pulmonary disease (COPD) and periodontal disease, as measured by assessments of gingival inflammation, probing depth, clinical attachment level, and/or radiographic bone loss, or oral hygiene indices.

EXCLUSION CRITERIA

Limited to studies of humans.

DATA COLLECTION AND ANALYSIS

The summary statistics used to analyze the RCTs included weighted mean differences in rates of disease between control and intervention groups. For cohort studies that measured differences in rates of disease between groups with and without oral disease, weighted mean differences, relative risks, or odds ratios were compared. A meta-analysis was performed on the 5 intervention studies to determine the relationship between oral hygiene intervention and rate of pneumonia in institutionalized patients.

MAIN RESULTS

Of the initial 1,688 studies identified, 36 satisfied all inclusion criteria and were read. Of these, 21 (11 case-control and cohort studies [study population 1,413] and 9 RCTs [study population 1,759]) were included in the analysis. 1. A variety of oral interventions improving oral hygiene through mechanical and/or topical chemical disinfection or antibiotics reduced the incidence of nosocomial pneumonia by an average of 40%. 2. Several studies demonstrated a potential association between periodontal disease and COPD.

REVIEWERS' CONCLUSIONS

1. Oral colonization by respiratory pathogens, fostered by poor oral hygiene and periodontal diseases, appears to be associated with nosocomial pneumonia. 2. Additional large-scale RCTs are warranted to provide the medical community with further evidence to institute effective oral hygiene procedures in high-risk patients to prevent nosocomial pneumonia. 3. The results associating periodontal disease and COPD are preliminary and large-scale longitudinal and epidemiologic and RCTs are needed.

Respiratory infection: how important is oral health?

The oral cavity has long been considered a potential reservoir for respiratory pathogens. Recently, there has been a renewed interest in the relation between oral flora and respiratory infection among "at-risk" patients such as patients from intensive care units or frail older adults. The mechanisms of infection could be colonization of the oral biofilm by respiratory pathogens followed by aspiration. More recent hypotheses relate to the presence in saliva of enzymes and cytokines associated with oral pathogens, and that could modulate the colonization of the respiratory tract or promote infection by respiratory pathogens. It is the aim of this paper to review the recent literature on this topic.

An exploration of the periodontitis-cancer association

PURPOSE

Periodontitis has been linked to the occurrence of various systemic diseases. The goal of this study was to explore the periodontitis-cancer association in the NHANES I Epidemiologic Follow-up Study.

METHODS

Data were available on 11,328 adults, age 25 to 74 years, who were diagnosed as dentate individuals with either periodontitis (n = 2092), gingivitis (n = 2603), a healthy periodontium (n = 2,671), or as individuals without teeth (edentulous n = 3,962) at the beginning of the follow-up. The main outcome measure was fatal cancer, as ascertained from death certificates.

RESULTS

Compared with individuals with a healthy periodontium, fatal cancer occurrence was positively associated with periodontitis at baseline (age and gender adjusted odds ratio = 1.55, 95% confidence interval: 1.25-1.92). Of the different cancer types, lung cancer demonstrated the strongest association. After adjustment for known risk factors for lung cancer, the magnitude of the association between periodontitis and lung cancer ranged between 1.48 (95% confidence interval: 0.88-2.50) and 1.73 (95% confidence interval: 1.01-2.97).

CONCLUSIONS

Associations between periodontitis and lung cancer mortality can be identified above and beyond adjustment for known risk factors for lung cancer. Despite these apparent unconfounded associations, there are reasons to believe that the periodontitis-cancer associations may be spurious.

Feasibility of an HA2 domain-based periodontitis vaccine

In a rat periodontitis model, preinoculation with the Porphyromonas gingivalis HA2 binding domain for hemoglobin provided protection from disease. Protection was associated with induced anti-HA2 immunoglobulin G (IgG) humoral antibodies. The IgG subclass ratios suggested that relatively lower Th2/Th1-driven responses were directly associated with protection when rHA2 was administered in saline.

Met and unmet need for dental services among active drug users in Miami, Florida

This study considers both met and unmet need for dental services among chronic drug users in Miami, Florida, and compares them with non-drug users recruited from the same neighborhoods (N = 1,479). Three primary findings emerged: (1) dental problems are among the most frequently reported health problems, (2) drug use is independently associated with need for dental services, and (3) injection drug use is independently associated with increased odds of unmet need for dental services. These findings suggest that policies that increase access to dental services for drug users and other disadvantaged groups are needed. These services could be integrated into existing behavioral health programs already targeting active drug users.

Epidemiologic associations between periodontal disease and chronic obstructive pulmonary disease

The nature of the relationship of periodontal disease to a number of systemic health outcomes, including chronic obstructive pulmonary disease (COPD), remains unclear. Various causal mechanisms have been proposed to explain the observed epidemiologic associations between periodontal diseases and respiratory diseases. We have reviewed the epidemiologic and clinical evidence for this association. The methodologic approach we have taken is based on a structured systematic review of the indexed biomedical literature on these subjects. The primary focus of this review was on the analysis of periodontal health status measures and their association with COPD, which includes chronic bronchitis and emphysema. We found that a paucity of published results exist on this specific relationship and those which do exist typically represent secondary analyses of existing data sets. Nevertheless, the epidemiologic evidence identified in this systematic review indicates that worse periodontal health status is associated with an increased risk of COPD, with odds ratios ranging from 1.45 to 4.50 (significant at the 95% confidence interval). However, it is possible that residual confounding by tobacco smoking may account in part for the observations. A causal association between periodontal health status and risk of COPD, although biologically plausible, remains speculative. Randomized controlled trials will be required in order to address the question of causality and to better understand the biological basis of these epidemiologic associations.

Oral bacteria and respiratory infection: effects on respiratory pathogen adhesion and epithelial cell proinflammatory cytokine production

Several microbiologic and epidemiologic studies have suggested an association between dental plaque, poor oral health, and respiratory diseases such as nosocomial pneumonia and chronic obstructive pulmonary disease (COPD). A number of hypotheses are suggested to help explain how oral bacteria may participate in the pathogenesis of respiratory infection. Resident bacteria in oral secretions are likely aspirated along with respiratory pathogens and may affect the adhesion of the later organisms to the respiratory epithelium. Preliminary studies performed in our laboratory suggest that oral bacteria may modulate the adhesion of respiratory pathogens to epithelial cell lines. In addition, oral bacterial products or cytokines in oral/pharyngeal aspirates may stimulate cytokine production from respiratory epithelial cells, resulting in recruitment of inflammatory cells. The resulting inflamed epithelium may be more susceptible to respiratory infection. Further preliminary data are presented that some species of oral bacteria may induce the release of proinflammatory cytokines from epithelial cell lines to an extent similar to that seen for respiratory pathogens.