Periodontal Pathogens and Respiratory Diseases - Evaluating Their Potential Association: A Clinical and Microbiological Study

Abstract

Objective:
To evaluate whether any potential association exists between respiratory diseases such as chronic obstructive pulmonary disease (COPD) and periodontal health status clinically and or microbiologically.

Materials and methods:
Fifty patients of COPD (test group) and 50 Patients without COPD (control group) were recruited for the study with more than 20 years of age with at least six natural teeth. All the patients were nonsmokers. Periodontal health was assessed by measuring clinical attachment loss (CAL) and gingival bleeding by using William's graduated periodontal probe. Microbiological evaluation was done by collecting sputum samples of the subjects with respiratory diseases to find out any periodontal pathogen in the lung fluid.

Result and conclusion:
The results showed that the subjects with COPD had significantly more bleeding sites (i.e. >20%) and had more of the clinical mean attachment loss (2.84 ± 0.66) than those without COPD. On the basis of the observed results of the study, we can hypothesize that the risk for COPD appeared to be significantly elevated when attachment loss was found to be severe.

Clinical significance:
It is conceivable that oral interventions that improve oral health status may prove to lower the severity of lung infection in susceptible populations.

Full text

S Vadiraj et al
610
ORIGINAL RESEARCH
Periodontal Pathogens and Respiratory Diseases—
Evaluating Their Potential Association: A Clinical
and Microbiological Study
S Vadiraj, Rashmita Nayak, Gopal Krishna Choudhary, Nitin Kudyar, BR Spoorthi
10.5005/jp-journals-10024-1373
ABSTRACT
Objective: To evaluate whether any potential association exists
between respiratory diseases such as chronic obstructive
pulmonary disease (COPD) and periodontal health status
clinically and or microbiologically.
Materials and methods: Fifty patients of COPD (test group)
and 50 Patients without COPD (control group) were recruited
for the study with more than 20 years of age with at least six
natural teeth. All the patients were nonsmokers. Periodontal
health was assessed by measuring clinical attachment loss
(CAL) and gingival bleeding by using William’s graduated
periodontal probe. Microbiological evaluation was done by
collecting sputum samples of the subjects with respiratory
diseases to find out any periodontal pathogen in the lung fluid.
Result and conclusion: The results showed that the subjects
with COPD had significantly more bleeding sites (i.e. >20%)
and had more of the clinical mean attachment loss (2.84 ± 0.66)
than those without COPD. On the basis of the observed results
of the study, we can hypothesize that the risk for COPD
appeared to be significantly elevated when attachment loss was
found to be severe.
Clinical significance: It is conceivable that oral interventions
that improve oral health status may prove to lower the severity
of lung infection in susceptible populations.
Keywords: Periodontal disease, Respiratory disease,
Periodontal medicine.
How to cite this article: Vadiraj S, Nayak R, Choudhary GK,
Kudyar N, Spoorthi BR. Periodontal Pathogens and Respiratory
Diseases—Evaluating Their Potential Association: A Clinical and
Microbiological Study. J Contemp Dent Pract 2013;14(4):610-615.
Source of support: Nil
Conflict of interest: None declared
INTRODUCTION
Recently, there has been resurgence of interest in field of
periodontal medicine. We view the term periodontal
medicine, as first suggested by Offenbacher1 that defines
as rapidly emerging branch of periodontology focusing on
the wealth of new data establishing a strong relationship
between periodontal health or disease and systemic health
or disease. Among these interactions, the relation between
periodontitis and respiratory diseases has been largely
studied. Recent cross-sectional epidemiological studies have
suggested a potential association between poor oral health
and respiratory diseases, such as pneumonia and chronic
obstructive pulmonary disease (COPD).2 COPD is a
condition in which there is chronic obstruction to airflow
with excess production of sputum as a result of chronic
bronchitis or emphysema.3
The most important established risk factor for COPD is
a history of prolonged cigarette smoking. Chronic exposure
to toxic atmospheric pollutants may also contribute to the
disease. Genetic conditions including a defective alpha
1-antitrypsin gene, variant 1-antichymotrypsin, alpha
2-macroglobulin, vitamin D-binding protein and blood
group antigen genes may also predispose subjects to COPD.4
Lower respiratory tract infections, including exacerbation
of COPD, depend on the initial colonization of microbial
pathogens to oral/pharyngeal surfaces. The pathogens are
subsequently shed into the salivary secretions, together with
oral bacteria, hydrolytic enzymes and proinflammatory
cytokines (Fig. 1).
Thus, the contents of this secretion may contaminate
and induce alterations of the respiratory epithelium.5 Oral
bacteria may modulate the adhesion of respiratory pathogens
to mucosal surfaces by altering the environment of the upper
airway to enhance the potential for respiratory pathogen
colonization of the lower respiratory tract.6 The resulting
inflamed mucosal epithelium may be more susceptible to
infection by respiratory pathogen.7,8

Periodontal Pathogens and Respiratory Diseases—Evaluating their Potential Correlation: A Clinical and Microbiological Study
The Journal of Contemporary Dental Practice, July-August 2013;14(4):610-615
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JCDP
The aim of the present study was to evaluate the
potential associations between respiratory diseases and
periodontal diseases.
MATERIALS AND METHODS
This study was carried out in Nijalingappa Medical College
and Hospital, Bagalkot, after obtaining the institutions
ethical clearance. This cross-sectional retrospective study
included a study population of 50 patients of COPD (test
group) and 50 patients without COPD (control group) were
recruited for the study. All the participants were nonsmokers
and were more than 20 years of age with at least six natural
teeth. They were randomly selected from the pool of patients
who came to the outpatient department. All patients enrolled
in the study voluntarily signed an informed consent.
A history of bronchitis and/or emphysema was recorded
and dichotomized variable (COPD) was also considered.
Periodontal health was assessed by measuring clinical
attachment loss (CAL) and gingival bleeding by using
William’s graduated periodontal probe. Microbiological
evaluation was done by collecting Sputum samples of the
subjects with respiratory diseases to find out any periodontal
pathogen in the lung fluid.
Periodontal disease was measured for determination
of:
• Clinical attachment loss (CAL) for each subject was
computed and dichotomized as those who had <2 mm
CAL and those who had >2 mm CAL. This cut off was
determined by examination of the distribution of MAL
for all the teeth examined, where 53.3% of the subjects
had a CAL <2 mm.
•Gingival bleeding: this was divided as <20% of sites
that bled on probing and >20% of sites that bled on
probing. This was done on the basis of the pilot study
done before which showed that more than 50% of the
patients had 20% bleeding sites.
MICROBIOLOGICAL EVALUATION
Microbiological evaluation was carried out using the sputum
samples of the subjects with respiratory diseases to find out
any periodontal pathogen in the lung fluid. Sputum sample
was collected and transferred to the microbiological
laboratory at the medical college. To create an anaerobic
environment GasPak™ EZ was used.
Principles of the procedure: The GasPak™ EZ gas
generating pouch systems are single-use systems that
produce atmosphere suitable to support the primary isolation
and cultivation of anaerobic, microaerophilic or capnophilic
bacteria by use of gas generating sachets inside single-use
resealable pouches. The GasPak™ EZ Gas Generating
Sachet consists of a reagent sachet containing inorganic
carbonate, activated carbon, ascorbic acid and water. When
the sachet is removed from the outer wrapper, the sachet
becomes activated by exposure to air. The activated reagent
sachet and specimens are placed in the GasPak EZ
incubation container and it is sealed. The sachet rapidly
reduces the oxygen concentration within the container.
At the same time, inorganic carbonate produces carbon
dioxide. For the cultivation of anaerobic bacteria, the
GasPak EZ anaerobe container system sachets produce an
anaerobic atmosphere within 2.5 hours, with greater than
15% carbon dioxide within 24 hours.
Culture: Cultures were grown on blood agar plates in an
anaerobic environment, at 95ºF (35ºC) for at least 48 hours
before the plates are examined for growth. Gram staining
was performed on the specimen at the time of culture. While
infections can be caused by aerobic or anaerobic bacteria
or a mixture of both, some infections have a high probability
of being caused by anaerobic bacteria.
STATISTICAL ANALYSIS
The mean and standard deviation values were calculated
for all clinical parameters. Chi-square test was used to
compare data among the groups and Student t-test. Analysis
was done by using SPSS (statistical package for social
sciences) version 14.0.
Demographic data of the sample population are
summarized in (Table 1). The mean age of subjects with
COPD was 48.9 ± 12.1 years, while the mean age of controls
was 44.0 ± 9.9 years. Number of females was less than males
both in test and control groups.
Fig. 1: Bacteria responsible for respiratory diseases and periodontal
diseases are shed into the saliva which is then aspirated into the
tracheal tree. The cytokines from periodontally diseased sites also
enter the tracheal tree where they attract inflammatory responses.
(Figures are being reproduced with permission from the American
Academy of Periodontology.
Source:
Role of oral bacteria in
respiratory infection. J Periodontol 1999; 70:793-802)

S Vadiraj et al
612
Patients with COPD had more bleeding sites (i.e.
>20%) than Non-COPD patients, who had less bleeding
sites (<20%). This was highly significant finding (×2 = 27.8,
p < 0.001,) (Table 2).
Patients with COPD had more of the clinical mean
attachment loss (2.84 ± 0.66) where as patients without
COPD had comparatively less of clinical mean attachment
loss (2.37 ± 0.60) which was highly significant (p < 0.001)
(Table 3).
Culture studies on the sputum showed only 30% of the
samples showed species like Streptococcus spp, Candida,
and Diphtheroids, Staphylococcus species, Porphyromonas
spp (Fig. 2).
Table 1: Age and sex distribution
No. of cases COPD Non-COPD
50 50
Age (yrs) Range 25-80 27-64
mean ± SD 48.9 ± 12.1 44.0 ± 9.9
SEX MF 34 32
16 18
Table 2: Bleeding sites (COPD
vs
Non-COPD)
Sites showing COPD N (%) Non-COPD Significance
bleeding of % N (%)
<20% 8 (16) 34 (68)
>20% 42 (84) 16 (32) *2 = 27.8
Total 50 50 p < 0.001, HS
*Chi-square test; HS: highly significant
Table 3: Clinical attachment loss (COPD
vs
Non-COPD)
Group No. of cases Clinical attachment loss Mean ± SD Median Significance
1.5 2.0 2.5 3.0 3.5
COPD 50 8 (16) – 11 (22) 16 (32) 15 (30) 2.84 ± 0.66 3.0 **p < 0.001,HS
Non-COPD 50 10 (20) 10 (20) 17 (34) 9 (18) 4 (8) 2.37 ± 0.60 2.5
**student t-test; HS: highly significant
Figs 2A to D: (A)
Porphyromonas spp
, (B)
Staphylococcus
,
Streptococcus
(C)
Staphylococcus
,
Streptococcus
(D) Candida
D
C
A
B

Periodontal Pathogens and Respiratory Diseases—Evaluating their Potential Correlation: A Clinical and Microbiological Study
The Journal of Contemporary Dental Practice, July-August 2013;14(4):610-615
613
JCDP
DISCUSSION
The findings of the present analysis, together with other
recently published studies support an association between
poor periodontal health and COPD.
In our study we found that patients with >20% of
bleeding sites were more in COPD patients (84%) compared
to non-COPD patients (16%). We also noticed that clinical
attachment loss was also more in COPD patients than in
non-COPD patients. This may be because of various reasons
which include:
1. Aspiration of oral pathogens (such as P. gingivalis, etc.)
into the lung.
2. Periodontal disease associated enzymes in saliva may
modify mucosal surfaces to promote adhesion and
colonization by respiratory pathogen.
3. Periodontal disease associated enzyme may destroy
salivary pellicles on pathogenic bacteria.
4. Cytokines originating from periodontal tissues may alter
respiratory epithelium to promote infection by
respiratory pathogen.5
Estimates have been made that 40% of all cases of
aspiration pneumonia, necrotizing pneumonia, lung
abscesses, involve anaerobic bacteria. A variety of oral
anaerobes and facultative anaerobes have been cultured from
infected lung fluids including P. gingivalis, Bacteroids
gracilus, Bacteroids oralis, Fusobacterium spp. Most, if
not all have been implicated in pathogenesis of periodontal
diseases. Distal airway of COPD patients frequently shows
bacterial colonization by nonpathogenic oral bacteria,
including oral Streptococci species. Indeed, Streptococci
viridans have been found to be cause of pneumonia in 4%
of the patients.9 Several studies have been documented
regarding lack of oral health in hospitalized patients. Lack
of attention to oral hygiene results in increase in mass and
complexity of dental plaque, which will lead to interaction
between indigenous plaque bacteria and respiratory
pathogens. This will lead to colonization of dental plaque
by respiratory pathogen. Dental plaque can therefore provide
reservoir for respiratory pathogens which will later shed
into saliva. Contamination of distal portion of respiratory
tree by this saliva can lead to pulmonary infection.
Figs 3A to D: (Figures are being reproduced with permission from the American Academy of Periodontology.
Source
: Role of oral
bacteria in respiratory infection. J Periodontol 1999;70:793-802) (A) Dental pathogens such as
P. gingivalis
produce enzymes (such as
proteases) that alter mucosal surface adhesion receptors for respiratory pathogens such as
H. influenzae
, which adhere, colonize and
can subsequently be aspirated into lungs to cause infection, (B) Oral bacteria such as
P. gingivalis
produce enzymes that degrade the
salivary molecules that normally form pellicle on the pathogens which prevents them from adhering to mucosal surfaces. (C) Oral
bacteria produce enzymes that degrade the salivary pellicles on mucosal layer. (D) Cytokines up regulate the expression of adhesion
receptors on the mucosal surfaces to promote respiratory pathogen colonization
A
B
C
D

S Vadiraj et al
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Saliva also contains wide variety of hydrolytic enzymes
like fibronectin and amount of enzyme activity in saliva is
related to the periodontal and oral hygiene status of subjects
tested.10 A direct relationship has been found between
fibronectin and oral hygiene status.11 It is conceivable that
in subjects having periodontal diseases and elevated level
of proteolytic bacteria such as P. gingivalis and spirochetes,
fibronectin activity may alter the mucosal epithelium to
increase the adhesion and colonization of respiratory
pathogen (Fig. 3A).
Recent evidence suggests that the respiratory pathogen
like H. influenzae binds to mucins contained within mucosal
secretions.12 This binding may involve sialic acid residues.
In the context of COPD, it is possible that subjects with
poor oral hygiene may have elevated levels of hydrolytic
enzymes in their saliva. These enzymes may process mucins
which reduce their ability to bind to and clear pathogens
such as H. influenzae (Fig. 3B).
Conversely enzymes may process the respiratory
epithelium to modulate adhesion of such pathogens to
mucosal surface (Fig. 3C).
In untreated periodontal diseases, oral pathogens
continuously stimulate cells of oral tissues and periodontium
to release wide variety of cytokines and other variety of
biologically active molecules.13 Cytokines produced by
these epithelial and connective tissue cells in response to
the bacteria include IL-1, IL-1, IL-6, IL-8 and TNF.
In fact, oral Streptococci which are abundant in dental
plaque, stimulate the release of high levels of these cytokines
from these cells. Epithelial cells also known to alter
expression of various cell adhesion molecules on their
surface in response to cytokine stimulation. Variation in
expression of such adhesion molecules may alter the
interaction of bacterial pathogen with the mucosal surface
(Fig. 3D).
Data from the National Health and Nutrition Examination
Survey I (NHANES I) where 23,808 individuals were
analyzed. Of these, 464 individuals reported a suspected
respiratory infection. Patients who had the highest oral
hygiene index (OHI) values were 4.5 times more likely to
have COPD than patients with an OHI of 0.14 Although this
study was cross-sectional in design, the result is supported
by a longitudinal study performed by Hayes et al. They
defined patients with a history of periodontal diseases as
assessed by radiographic alveolar bone loss (ABL) and
found that ABL at baseline is an independent risk factor for
COPD, and increased ABL is associated with increased risk
for COPD.15 Although both results are interesting, these
data need to be interpreted with caution due to the imprecise
definitions of respiratory diseases. Travis described a
biologically plausible mechanism to explain the theoretical
association between emphysema and periodontal diseases.
Both diseases share very similar pathological processes that
are characterized by the recruitment of neutrophils to
inflammatory sites. Destruction of connective tissue is a
common result in both diseases.
To summarize in short, in patients with poor oral hygiene,
i.e. with inadequate plaque control and accompanying
periodontal disease will lead to pulmonary disease. It should
be noted that we are not arguing that poor oral health alone
is responsible for COPD. Rather, poor oral health may work
in concert with other factors (such as continued smoking,
environmental pollutants, viral infections, allergy and/or
genetic factors) to promote the progression and/or exacerbation
of COPD. Further investigations will establish the role of
oral health in the initiation and progression of COPD.
ACKNOWLEDGMENT
We are thankful to the staff of Department of Periodontology,
PMNM Dental College and Hospital, Bagalkot, Karnataka
and Department of Microbiology, Medical College,
Bagalkot, Karnataka, India for their support.
REFERENCES
1. Offenbacher S. Periodontal diseases. Pathogenesis. Ann
Periodontol 1996;1:821-878.
2. Scannapieco FA, Stewart EM, Mylotte JM. Colonization of
dental plaque by respiratory pathogens in medical intensive care
patients. Crit Care Med 1992;20:740-745.
3. Ingram RH. Chronic bronchitis, emphysema and airway
obstruction. In: Isselbacher KJ, Brounwald E, Wilson JD, Martin
JB, Fauci AS, Kasper DL, editors. Harrison’s Principles of
Internal Medicine, New York: Mcgraw-Hill 1994;1197-1206.
4. Stanford AJ, Weir TD, Pare PD. Genetic risk factors for chronic
obstructive pulmonary disease. Eur Resp J 1997;10:1380-1391.
5. Scannapieco FA. Role of oral bacteria in respiratory infection.
J Periodontol 1999;70:793-802.
6. Scannapieco FA, Mylotte JM. Relationship between periodontal
disease and bacterial pneumonia. J Periodontol 1996;67:
1114-1122.
7. Hedges SR, Agace WW, Svanborg C. Epithelial cytokine
responses and mucosal cytokine networks. Trends Microbial
1995;3:266-270.
8. Svanborg C, Hedlund M, Connell H, et al. Bacterial adherence
and mucosal cytokine responses. Receptors and transmembrane
signaling. Ann NY Acad Sci 1996;797:177-190.
9. Torres A, Dorca J, Zalacain R. Community acquired pneumonia
in chronic obstructive pulmonary disease: a Spanish multicenter
study. Am J Crit Care Med 1996;154:1456-1461.
10. Nakamura M, Slots J. Origin and relationship to periodontal
diseases. J Periodont Res 1983;18:559-569.
11. Gibbons RJ, Etherden I. Fibronectin degrading enzymes in saliva
and its relationship to oral cleanliness. J Periodont Res 1986;
21:386-395.
12. Reddy MS, Murphy TF, Faden HS, Berstein JM. Middle ear
mucin glycoprotein: purification and interaction with non-
typable. Otolaryngol Head Neck Surg 1997;116:175-180.

Periodontal Pathogens and Respiratory Diseases—Evaluating their Potential Correlation: A Clinical and Microbiological Study
The Journal of Contemporary Dental Practice, July-August 2013;14(4):610-615
615
JCDP
13. Reddi K, Wilson M, Nair S, Poole S, Henderson B. Comparison
of the proinflammatory cytokine–stimulating activity of the
surface associated proteins of periodontopathic bacteria.
J Periodont Res 1996;31:120-130.
14. Scannapieco FA, Papandonatos GD, Dunford RG. Associations
between oral conditions and respiratory disease in a national
sample survey population. Ann Periodontol 1998;3:251-256.
15. Hayes C, Sparrow D, Cohen M, Vokonas PS, Garcia RI. The
association between alveolar bone loss and pulmonary function:
the VA Dental Longitudinal Study. Ann Periodontol 1998;
3:257-261.
ABOUT THE AUTHORS
S Vadiraj (Corresponding Author)
Reader, Department of Periodontics, PDU Dental College and
Hospital, Solapur, Maharashtra, India, e-mail: vadi24@rediffmail.com
Rashmita Nayak
Reader, Department of Periodontics, Institute of Dental Sciences
Bhubaneshwar, Odisha, India
Gopal Krishna Choudhary
Reader, Department of Prosthodontics, Institute of Dental Sciences
Bhubaneshwar, Odisha, India
Nitin Kudyar
Senior Lecturer, Department of Periodontics, Indira Gandhi Government
Dental College and Hospital Jammu, Jammu and Kashmir, India
BR Spoorthi
Reader, Department of Oral Pathology, MS Ramaiah Dental College
and Hospital, Bengaluru, Karnataka, India