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Use of floss/interdentalbrushes is associated withlower risk for newcardiovascular eventsamong patients withcoronary heart disease
Reichert S, Schlitt A, Beschow V, Lutze A, Lischewski S, Seifert T, Dudakliewa T,
Gawe R, Werdan K, Hofmann B, Schaller H-G, Schulz S. Use of floss/interdental
brushes is associated with lower risk for new cardiovascular events among patients
with coronary heart disease. J Periodont Res 2014; doi: 10.1111/jre.12191 . 2014John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Background and Objective: Periodontitis has been found to be associated with
coronary heart disease (CHD) and stroke. However, only little is known about
whether periodontitis and associated confounders are associated with new car-
diovascular events among patients with CHD.
Material and Methods: A total of 942 inpatients with CHD were examined
regarding periodontitis, oral care habits, bacteria in the subgingival biofilm and
the expression of interleukin-(IL)-6 c. (coding DNA)174 genotypes (rs 1800793)
to determine whether these confounders are associated with new cardiovascular
events within a 1-year follow-up period. Adjusted hazard ratios (HR) with
respect of age, gender, smoking, body mass index, use of aids for interdental
hygiene, plaque index, occurrence of severe periodontitis and further internal
diseases such as diabetes, hypertension, dyslipoproteinemia, number of missing
teeth, serological parameters and IL-6 genotypes were generated with Cox
regression.
Results: In all, 941 cardiovascular patients completed the 1-year follow up and
7.3% of the patients achieved the primary endpoint (myocardial infarction:
2.1%, stroke/transient ischemic attack: 1.8%, cardiovascular deaths: 3.4%).
Patients who reported practicing interdental cleaning were younger, less likely to
be male or to have severe periodontitis, had a reduced tobacco exposure, had
fewer missing teeth, less indices for plaque and bleeding on probing and a
significant decreased adjusted risk for new cardiovascular events (HR = 0.2, CI0.060.6, p = 0.01) than those patients with CHD who did not report practicinginterdental cleaning. We did not obtain significant increased HR for patients
with severe periodontitis (HR = 1.2, CI 0.72.1, p = 0.53), carriers of the IL-6genotypes GC or CC (HR = 1.4, CI 0.82.5, p = 0.24) and did not find a signifi-cant association between the number of detected various oral species and the
incidence of the combined endpoint (HR = 0.9, CI 0.81.01, p = 0.07).
S. Reichert1, A. Schlitt2,
V. Beschow1, A. Lutze1,3,
S. Lischewski1, T. Seifert1,3,
T. Dudakliewa3, R. Gawe3,
K. Werdan3, B. Hofmann4,
H.-G. Schaller1, S. Schulz11Department of Operative Dentistry and
Periodontology, Martin Luther University Halle-
Wittenberg, Halle, Germany, 2Department of
Cardiology, Paracelsus-Harz-Clinic Bad
Suderode, Quedlinburg, Germany, 3Department
of Internal Medicine III, Heart Centre of the
University Clinics Halle (Saale), Martin Luther
University Halle-Wittenberg, Halle, Germany
and 4Department of Cardiothoracic Surgery,
Heart Centre of the University Clinics Halle
(Saale), Martin Luther University Halle-
Wittenberg, Halle, Germany
Dr Stefan Reichert, PD, Department of
Operative Dentistry and Periodontology, Martin
Luther University Halle-Wittenberg, Groe
Steinstrasse 19, 06108 Halle (Saale), Germany
Tel: +49 345 557 3772
Fax: +49 345 557 3773
e-mail: stefan.reichert@uk-halle.de
Key words: coronary heart disease; gene
polymorphism; interleukin-6; periodontitis;
prognostic marker
Accepted for publication March 26, 2014
J Periodont Res 2014All rights reserved
2014 John Wiley & Sons A/S.Published by John Wiley & Sons Ltd
JOURNAL OF PERIODONTAL RESEARCH
doi:10.1111/jre.12191
Conclusions: These findings suggest that flossing and brushing of interdental
spaces might reduce the risk for new cardiovascular events among patients with
CHD. The hypothesis that interdental cleaning per se reduces the risk of new
cardiovascular events should be examined in an interventional study.
In the last years numerous studies
were carried out to investigate
whether periodontitis is a putative
risk factor for atherosclerosis (1,2)
and subsequent diseases such as coro-
nary heart disease (CHD) (3) and
stroke(4). Indeed, meta-analyses have
shown that periodontal disease is an
independent risk factor for CHD
(57) and cerebrovascular disease (8).Furthermore, the occurrence of peri-
odontopathogens in the subgingival
plaque was found to be associated
with the occurrence of CHD (9).
Interleukin (IL)-6 is a proinflamma-
tory cytokine, which stimulates hepa-
tic production of acute phase proteins
such as C-reactive protein (CRP),
modulates adhesion of monocytes on
endothelial cells and promotes coagu-
lation of platelets (10). Therefore,
IL-6 might be involved in the patho-
genesis of both periodontitis (1113)and CHD (1416). It has beenreported that IL-6 c.174G/C poly-morphisms influenced IL-6 serum lev-
els (17). The genotype GG was
identified as a high-producer genotype
whereas carriers of the GC and CC
genotypes showed lower IL-6 serum
levels.
The IL-6 c.174G/C polymorphismwas found to be associated to both
chronic (18) and aggressive periodon-
titis (19) as well as to the subgingival
colonization with periodontopatho-
gens (20). Furthermore, this polymor-
phism was found associated with
CHD (2123). Hence, IL-6 genotypesat promoter position 174 may beprognostic markers for CHD and
periodontitis and should be consid-
ered in multivariate risk factor
analyses.
So far, only one study from Fin-
land has investigated the role of den-
tal infection for new coronary events
among patients with proven coronary
artery disease (24). Therefore, the aim
of the present, prospective, longitudi-
nal study was to investigate whether
oral hygiene habits, severe periodonti-
tis, presence of periodontopathogens
in the subgingival biofilm, or certain
IL-6 c.174 genotypes represent inde-pendent risk factors for the incidence
of new cardiovascular events (com-
bined endpoint: myocardial infarction,
stroke/transient ischemic attack [TIA],
myocardial death) among inpatients
suffering from CHD.
Material and methods
Study population
At baseline, 942 consecutive German
patients of Caucasian origin from cen-
tral Germany admitted to the Depart-
ment of Internal Medicine III or
Department of Cardiothoracic Sur-
gery of the Martin Luther University
Halle-Wittenberg with angiographical-
ly proven CHD were prospectively
included from October 2009 to Febru-
ary 2011. The investigations were car-
ried out in accordance with the
ethical guidelines of the Declaration
of Helsinki and its amendment in
Tokyo and Venice. The study was
approved by the ethics committee of
the Martin Luther University Halle-
Wittenberg. Informed written consent
was obtained from each patient.
Inclusion criteria were age
18 years and known CHD asdefined by a stenosis of 50% of amain coronary artery by coronary
angiography or percutaneous coro-
nary intervention or coronary artery
bypass surgery. At least four own
teeth except for the third molars
needed to be present. Exclusion crite-
ria were pregnancy, antibiotic therapy
during the last 3 mo, subgingival scal-
ing and root planing during the last
6 mo or psychological reasons that
rendered study participation impracti-
cal. Patients with current alcohol or
drug abuse might be not completely
able to understand the aim of the
study and the necessity of an addi-
tional dental examination. If a drug
or alcohol abuse was known from
patients file or a patient reported
during the interview about a current
drug or alcohol abuse s/he was not
included in the study.
Ages, body mass index, current or
past diseases (e.g. diabetes mellitus,
hypertension and dyslipoproteinemia)
were assessed as part of the patients
medical history. Diabetes mellitus
was diagnosed when it was known
from the history and/or the patients
were receiving dietary or antidiabetic
drug therapy in the hospital, or had
a fasting blood glucose of 7 mM.Dyslipoproteinemia was assumed if
this had been prediagnosed, a ther-
apy with lipid-lowering agents was
being administered or a fasting cho-
lesterol of > 5.2 mM or low-densitylipoprotein cholesterol > 3.9 mM waspresent. Arterial hypertension was
defined as hypertension that was
diagnosed before the current hospital-
ization and/or the patient was taking
antihypertensive medication or when
a blood pressure of > 140/90 mmHgwas measured. Furthermore, patients
were asked about their smoking
behaviors. A person who smoked a
minimum of one cigarette per day
at the time of questioning was
considered a current smoker. For
quantification of cigarette smoking,
pack-year of each current smoker
was calculated. When calculating the
pack-year, former smokers were not
considered. Furthermore, all patients
underwent detailed clinical and bio-
chemical investigation. For instance,
serum parameters, including hemo-
globin (mM), IL-6 (pg/mL), CRP
(mg/dL) and creatinine (lM) wererecorded.
2 Reichert et al.
During the periodontal examina-
tion, patients were asked about the
frequency of tooth brushing per day
and whether they use dental floss or
interdental brushes to clean the inter-
dental spaces. The clinical assessment
involved determining the plaque index
(PI) (25) and assessing bleeding on
probing (BOP) (26). In both indexes,
four sites around each tooth (mesio-
buccal, mid-buccal, disto-buccal and
mid-lingual) were examined. The mea-
surements for both maximal clinical
probing depth (distance between gin-
gival margin and bottom of the
pocket) and maximum clinical attach-
ment loss (distance between cemento-
enamel junction and bottom of the
pocket) were taken using a pressure-
sensitive probe (DB764R; Aesculap
AG & Co. KG, Tuttlingen, Germany)
at six sites around each tooth (mesio-
buccal, mid-buccal, disto-buccal, me-
sio-lingual mid-lingual, disto-lingual).
For the diagnosis of periodontitis, we
used the published criteria for a two-
level periodontitis case definition for
risk factor research. Periodontitis was
defined as the presence of proximal
attachment loss of 3 mm in 2nonadjacent teeth. Severe periodonti-
tis was defined as the presence of
proximal attachment loss of 5 mmin at least 30% of the teeth (27).
A 1-year follow-up was performed
and the incidence of the combined
endpoint defined as myocardial infarc-
tion, stroke/TIA and death from car-
diovascular causes was calculated.
For acquiring follow-up data, a stan-
dardized questionnaire was sent out.
If patients did not return the
questionnaires, a telephone interview
was conducted with the patient or
patients relatives and physician, when
the patient was dead. At an unknown
current address or telephone number,
we contacted civil registration offices
and requested information about cur-
rent address or date of death. If the
patients death was already known,
for instance for individuals who died
in our hospital, we did not send out a
questionnaire. Instead, the informa-
tion about the cause and date of
death was obtained from electronic
patient files.
Determination of interleukin-6 c.174
G/C genotypes
The genomic DNA was obtained
from leukocytes in venous EDTA
blood using a commercial DNA
extraction kit (QIAamp; Qiagen,
Hilden, Germany) in accordance with
the manufacturers instructions.
Genotype analyses were carried out
using a commercial available polymer-
ase chain reaction (PCR)-SSP kit
(CTS-PCR-SSP Tray kit, Collabora-
tive Transplant Study, Department of
Transplantation Immunology of the
University Clinic of Heidelberg,
Germany) as described previously (28).
After agarose gel electrophoresis, the
results were evaluated visually. Bands
of 430 bp correspond to the various
IL-6 alleles. According to db single
nucleotide polymorphism, the identifi-
cation number of the single nucleotide
polymorphism was rs 1800793.
Molecular biological assessment of
periodontal bacteria in subgingival
pockets
Microbial samples were taken from
the deepest pocket of each quadrant
by inserting one sterile paper point
for 20 s. The four bacterial plaque
samples taken from each patient were
pooled in one tube. Aggregatibacter
actinomycetemcomitans, Porphyromon-
as gingivalis, Prevotella intermedia,
Tannerella forsythia, Treponema denti-
cola, Peptostreptococcus micros,
Fusobacterium nucleatum, Campylo-
bacter rectus, Eubacterium nodatum,
Eikenella corrodens and a combina-
tion of Capnocytophaga sputigena,
Capnocytophaga gingivalis and Capno-
cytophaga ochracea were specifically
assessed by PCR in a commercial lab-
oratory (micro-Ident plus test; HAIN-
Diagnostica, Nehren, Germany). The
procedure for detecting bacterial
DNA can be divided into three steps:
isolation of bacterial DNA, multiplex
amplification with biotinylated
species-specific primers by PCR, and
reverse hybridization. These steps
have been described in detail in a pre-
viously published paper of our group
(29). The detection limit for all bacte-
ria was 104 genome equivalents with
the exception of Aggregatibacter
actinomycetemcomitans with 103 gen-
ome equivalents. The numbers of
detected bacterial species per individ-
ual that were over the detection limit
were counted.
Statistical evaluation
Statistical analyses were carried out
using commercially available software
(SPSS v.19.0 package; IBM, Chicago,
IL, USA). Values of p 0.05 wereconsidered significant. The distribu-
tion of the IL-6 c.174GG, GC andCC among the inpatients with CHD
was tested according to the HardyWeinberg equilibrium.
Metric demographic, clinical and
serological data were checked for
normal distribution using the
KolmogorovSmirnov test and theShapiroWilk test. As all metric valueswere not normally distributed, they
were plotted as median and 25th/75th
percentiles. For statistical evaluation,
the MannWhitney U test was used.Pack-year was calculated by multi-
plying the number of packs (one
pack = 20 cigarettes) of cigarettessmoked per day by the number of
years the person has smoked.
To evaluate adjusted odds ratios
for occurrence of severe periodontitis
among patients with CHD, a logistic
regression analysis was conducted
with respect of the cofactors age, gen-
der, body mass index, pack-year,
number of detected different bacterial
species per individual, frequency of
tooth brushing per day, use of floss/
interdental brushes and expression of
IL-6 c.174 G/C genotypes.For survival evaluation, Kaplan
Meier analyses with the log-rank test
were applied. Adjusted hazard ratios
were generated with Cox regression
and with respect of the variables age
gender, body mass index, pack-year,
hypertension, dyslipoproteinemia, dia-
betes, serum levels for IL-6, CRP,
hemoglobin and creatinine, IL-6 c.174 genotypes (GC+CC vs. GG),number of missing teeth, number of
detected different bacterial species per
individual, frequency of tooth
Periodontitis and cardiovascular events 3
brushing per day and use of floss/
interdental brushes were included in
one model.
Results
Periodontal, microbial and serologic
conditions in inpatients with
coronary heart disease
All baseline data are presented in
Table 1. The overall prevalence of
severe periodontitis among our
patients with CHD was almost 50%.
A median of 10 missing teeth (excep-
tion third molars) was recorded. The
median for the number of detected
bacterial species was 7. The majority
of patients with CHD (74.9%)
brushed their teeth more than once a
day but only 20.1% used floss and/or
interdental brushes. The overall med-
ian values for CRP and IL-6 were
above the reference values for healthy
persons.
The distribution of the IL-6 c.-174
genotypes GG, GC and CC fulfilled
the criteria of the HardyWeinberg
equilibrium. Of the patients, 70%
were carriers of IL-6 c.174 genotypesGC or CC.
Factors associated to the
occurrence of a severe periodontitis
among patients with coronary heart
disease
The age, male gender, the number of
detected oral species, and occurrence
of IL-6 c.174 GC or CC genotypeswere associated with an increased
adjusted odds ratio for severe peri-
odontitis whereas the use of floss/
interdental brushes was associated
with a lower adjusted odds ratio
(Table 2). Patients who used floss
and/or interdental brushes were signif-
icantly younger, more often females,
and had lower values for pack-years,
occurrence of a severe periodontitis,
missing teeth, PI and BOP in compar-
ison to patients with CHD, who did
not use any aids for interdental
hygiene (Table 3).
Association of severe periodontitis,
periodontal and microbial
conditions and IL-6 c.174
genotypes with the incidence of the
combined endpoint within the 1-year
follow-up period
A total of 942 patients with CHD
were prospectively included in the
longitudinal cohort study. For one
patient (0.1% dropout rate) we did
not obtain 1-year follow-up data.
During the mean follow-up of
54 11 wk, 20 (2.1%) myocardialinfarctions, 17 (1.8%) strokes/TIAs
and 32 (3.4%) cardiovascular deaths
were recorded. The total incidence of
the combined endpoint was 7.3%.
Bivariate analyses The KaplanMeier plot (Fig. 1) showed a signifi-
cantly lower incidence for the
combined endpoint among patients
who used dental floss/interdental
brushes than among individuals who
did not use these aids for oral hygiene
(1.6% vs. 8.8%, log-rank p = 0.001).Moreover, patients with CHD who
had only 010 missing teeth showed asignificantly lower incidence of the
combined endpoint than individuals
Table 1. Periodontal conditions, prevalence of internal diseases, biochemical parameters,
distribution of c.174 interleukin-6 genotypes among inpatients with coronary heart dis-ease
Variables
Stationary patients
with coronary
heart disease
n = 942
Demographic parameters
Age (years), median (25th/75th percentiles) 68.8 (59.5/74.9)
Males (%) 74.0
Pack-years, mean (SD) 3.0 (9.7)
Body mass index (kg/m2), median (25th/75th percentiles) 28.1 (25.3/30.8)
Prevalence of internal diseases
Diabetes (%) 34.2
Hypertension (%) 87.6
Dyslipoproteinemia (%) 58.7
Oral care habits and periodontal conditions
Frequency of tooth brushing per day (%)
Once a day 23.9
More than once a day 74.9
Use of interdental floss/brush (%) 20.1
No periodontitis (%) 2.1
All periodontitis cases (%)a 97.9
Severe periodontitis cases (%)b 47.7
Plaque index (%), median (25th/75th percentiles) 0.8 (0.5/1.4)
Bleeding index (%), median (25th/75th percentiles) 5.6 (1.8/12.1)
Number of missing teeth, median (25th/75th percentiles) 10.0 (5.0/18.0)
Number of detected oral species, median
(25th/75th percentiles)
7.0 (5.0/8.0)
Serological parameters
C-reactive protein (mg/dL), median (25th/75th percentiles)
Reference: < 0.58.9 (3.6/32.1)
Interleukin 6 (pg/mL)
Median (25th/75th percentiles)
Reference: < 6.4
7.4 (3.6/15.7)
Creatinine (lM), median (25th/75th percentiles)Reference: males: < 102; females: < 88
87.0 (72.0/106.3)
Hemoglobin (mM)
Median (25th/75th percentiles)
Reference: males 8.711.2; females: 7.39.9
8.3 (7.2/9.1)
IL-6 c.174 G>C genotypes (rs 1800793) (%)GG 29.8
GC 49.3
CC 20.95
aAttachment loss of 3 mm in at least two non-adjacent teeth.bAttachment loss of 5 mm in 30% of teeth present.
4 Reichert et al.
who had 1124 missing teeth (4.9%vs. 9.8%, log-rank p = 0.004) (Fig. 2).The incidence for the combined end-
point tended to be higher in patients
with severe periodontitis than in indi-
viduals who did not have severe peri-
odontitis (8.9% vs. 5.9%, log-rank
p = 0.095). There was no significantdifference regarding the incidence of
the combined endpoint in patients
where none to five various bacterial
species were detected in comparison
to those with six to 11 bacteria (7.9%
vs. 7.0%, log-rank p = 0.515). IL-6c.174 genotypes were not signifi-
cantly associated with different inci-
dence rates of the combined endpoint
(GG 6.1%, GC 7.1%, CC 9.6%,
log-rank p = 0.340).
Multivariate analysis To generate
adjusted hazard ratios the influence of
severe periodontitis, oral hygiene hab-
its, number of missing teeth and
expression of IL-6 c.174 genotypeson the cardiovascular endpoint, was
investigated with Cox regression with
respect to known confounders for
both, periodontitis and CHD. Only
the use of dental floss/interdental
brushes was associated with a signifi-
cantly decreased adjusted hazard ratio
for the combined endpoint (Table 4).
Discussion
Periodontitis, periodontopathogens,
oral hygiene habits, number of miss-
ing teeth and polymorphisms in genes
of cytokines such as IL-6 might be
indicative for new cardiovascular
events among patients who suffer
from CHD. If such associations were
identified, the diagnosis and therapy
of periodontal diseases would need to
be regularly integrated into cardiac
rehabilitation programs to reduce the
risk for such events.
The purpose of the present study
was to evaluate the impact of these
periodontal and genetic conditions on
further cardiovascular events (com-
bined endpoint: myocardial infarction,
stroke/TIA, myocardial death) within
a 1-year follow-up period among
inpatients with proven CHD. The
hazard ratios should be controlled for
known confounders for both peri-
odontitis and CHD.
Both the overall prevalence of peri-
odontitis (97.9%) and prevalence of a
severe periodontitis (47.7%) among
our patients with CHD (Table 1) were
slightly higher than the epidemiologic
data obtained in the fourth German
Dental Health Survey (DMS IV). In
that study, the overall prevalence of
periodontitis was 87.8% (Community
Periodontal Index [CPI] Code 3 or 4)
among individuals aged from 65 to
74 years and 39.9% had a severe peri-
odontitis (CPI Code 4) (30). In con-
trast, the number of missing teeth
(except for the third molars) was not
higher among our patients with CHD
(14.0 vs. 14.2) (31).
The differences regarding the preva-
lence of periodontitis among patients
with CHD in comparison to the DMS
IV data should be interpreted with
caution, however, and we cannot con-
clude from these data that the preva-
lence of periodontal disease is higher
among patients with CHD in general.
For instance, CPI codes were only
recorded on index teeth and a pocket
depth on 45 mm (Code 3) wasdefined as periodontitis. In the present
Table 2. Logistic regression analysis for the occurrence of a severe periodontitisa among
patients with cardiovascular heart disease
Confounding variables
Odds
ratio
95%
lower
CI
upper p values
Age 1.02 1.01 1.04 0.002
Male gender 1.42 1.03 1.95 0.03
Body mass index 0.99 0.96 1.02 0.44
Pack-years 1.03 1.01 1.05 0.002
Frequency of tooth brushing per day 0.87 0.68 1.11 0.26
Use of floss/interdental brushes 0.50 0.35 0.71 < 0.001Number of detected bacterial various
species per individual
1.14 1.08 1.21 < 0.001
Diabetes 1.22 0.91 1.64 0.18
IL-6 c.174 GC or CC vs. GG 1.11 0.83 1.49 0.009
aAttachment loss of 5 mm in 30% of teeth present.
Table 3. Demographic, general and periodontal conditions in patients with coronary heart
diseases in depending on the use of aids for approximal hygiene
Variable
No use of floss/
interdental brushes
n = 753
Use of floss/
interdental brushes
n = 189 p
Age (years), median
(25th/75th percentiles)
69.2 (59.7/75.5) 67.3 (59.2/72.0) 0.006c
Males (%) 74.0 30.7 < 0.001b
Pack-years, mean (SD) 3.3 (10.4) 1.5 (5.9) 0.045c
Body mass index (kg/m2), median
(25th/75th percentiles)
28.1 (25.2/30.8) 27.9 (25.4/30.5) 0.649c
Severe periodontitis (%)a 51.9 30.7 < 0.001b
Missing teeth (exception third
molars), median (25th/75th
percentiles)
12.0 (6.0/20.0) 7.0 (3.1/10.0) < 0.0001c
Plaque index (%), median
(25th/75th percentiles)
0.9 (0.6/1.6) 0.6 (0.4/0.8) < 0.0001c
Bleeding upon probing (%),
median (25th/75th percentiles)
6.3 (2.2/12.5) 3.5 (0.9//6.9) < 0.0001c
Number of bacterial species per
individual, median (25th/75th
percentiles)
7 (5.0/8.0) 7 (4.0/8.0) 0.963c
aSevere periodontitis: Attachment loss of 5 mm in 30% of teeth present.bChi-squared test with Yates correction.cMannWhitney U-test.
Periodontitis and cardiovascular events 5
study, the threshold for diagnosis of a
periodontitis case was a clinical
attachment loss of at least 3 mm in at
least two nonadjacent teeth. More-
over, all teeth were investigated.
As only 20 (2.1%) of our study
patients with CHD did not have peri-
odontitis, a separate statistical evalua-
tion for this cohort would not be
meaningful. Therefore, this group was
added to patients who had no severe
periodontitis.
Our main results showed a signifi-
cantly decreased adjusted HR for the
combined endpoint among patients
who used dental floss/interdental
brushes for oral hygiene (Table 4).
According to our results this associa-
tion might be due to the favorable
effect of proper oral hygiene in the
plaque and bleeding index, number of
missing teeth and prevalence of severe
periodontitis (Table 3). The inverse
association between use of floss/inter-
dental brushes and prevalence of a
severe periodontitis was additionally
confirmed in a binary logistic regres-
sion model (Table 2). The long-term
effect of effective plaque control on
periodontitis and tooth mortality has
already been demonstrated (32). The
use of aids for cleaning interdental
spaces as an adjunct to brushing was
found to remove more dental plaque
than brushing alone (33). In contrast
to our results, a Scottish health survey
(34) obtained (Table 4) an inverse
association between the frequency of
dental brushing and the risk of CHD.
The use of floss/interdental brushes,
however, was not evaluated.
Although our data suggest a direct
link between oral hygiene and the
incidence of the combined endpoint,
further confounders should be dis-
cussed. For instance, patients who
used aids for interdental hygiene were
significantly younger, more often were
females and had a lower smoke
exposure than their counterparts who
did not clean the interdental spaces
(Table 3). These confounders might
influence the risk for further cardio-
vascular events. It is also conceivable
that patients with a proper interdental
hygiene were in better general health
and more motivated and/or able to
use floss/interdental brushes regularly.
Furthermore, good oral care habits
such as use of aids for interdental
hygiene might reflect a higher health
consciousness in general. Despite this
uncertainty regarding the underlying
biologic effect of oral hygiene to the
incidence of new cardiovascular
events, the use of interdental brushes/
dental floss might be recommended,
in particular, to patients with CHD.
The hypothesis that interdental
cleaning per se reduces the risk of
new cardiovascular events should be
examined in an interventional study.
0.8
0.6
0.4
0.2
0.0
0 20 40 60 100Wk of follow up
Co
mb
ined
en
dp
oin
t
80
1.0
NoYes
Use of dentalfloss/interdental
brushes
Fig. 1. KaplanMeier plot for combined endpoint (stroke/transient ischemic attack, car-
diovascular death, myocardial infarction) according to the use of aids for interdental
hygiene (use of floss/interdental brushes vs. no use of floss interdental brushes).
010 missing teeth1124 missing teeth
0.8
0.6
0.4
0.2
0
0.0
20 40 60 100Wk of follow up
Co
mb
ined
en
dp
oin
t
80
1.0
Fig. 2. KaplanMeier plot for combined endpoint (myocardial infarction, stroke/transient
ischemic attack, myocardial death) according to the number of missing teeth (010 missing
teeth vs. 1124 missing teeth).
6 Reichert et al.
Although oral hygiene habits were
associated to both, the prevalence of
a severe periodontitis (Table 2) and
incidence of the cardiovascular end-
point (Table 4) we found only a trend
but not a significant association
between severe periodontitis and the
incidence of the combined endpoint at
all. In contrast to our result, a previ-
ous study (24) showed a significant
positive association between dental
infection and the risk of new coronary
events among patients with proven
coronary artery disease. In particular,
differences in the study design (e.g.
number of studied individuals, follow-
up intervals and definition of the end-
point, including cofactors) might be
responsible for these inconsistent
results. For instance, in a previous
study (24) only 214 individuals were
investigated but the follow-up period
was 7 years. The endpoint was
defined as incidence of fatal and non-
fatal coronary events and overall
mortality but incidence of TIA/stroke
was not investigated. Moreover, in
comparison to our multivariate Cox
regression the socioeconomic status,
the number of previous myocardial
infarctions, and serum lipids were
included as confounding variables.
A Swedish longitudinal study (35)
reported a dose-dependent relation-
ship between number of teeth and
all-cause and cardiovascular disease
mortality. The authors assumed that
severe tooth loss might be an indica-
tor for life-long dental infections,
which could represent an important
risk factor for atherosclerotic vascular
changes. The results of that study are
partially confirmed by our findings
because, according to the log-rank
test (Fig. 2), the incidence of the com-
bined endpoint was associated with
the number of missing teeth. How-
ever, this was not significant in the
multivariate model (Table 4).
The positive association between
the periodontal pathogen burden and
the prevalence of CHD obtained in a
previous cross-sectional controlled
study (9) could not be confirmed by
our results. According to our findings,
the number of detected bacterial spe-
cies per individual was indeed associ-
ated to the prevalence of a severe
periodontitis (Table 2) but not to the
incidence of the combined endpoint
(Table 4).
This different result in comparison
to the preceding study (9) could be
due to differences in study designs
(cross-sectional vs. longitudinal) or
the different methods for detecting
periodontopathogens and thus differ-
ent detection limits.
There was trend for a positive asso-
ciation between the individual expres-
sion of the genotypes IL-6 c.-174 GC
or CC and the prevalence of a severe
periodontitis among patients with
CHD (Table 2). However, although
our patients who were carriers of IL-6
c.174 CC or GC genotypes usuallymet the combined endpoint, this was
not significant after both log-rank test
and Cox regression. Therefore, our
results did not support previous cross-
sectional studies and meta-analyses,
which identified the IL-6 c.174 G/Cpolymorphism as indicative for car-
diovascular diseases (2123,36).
Limitations of the study
The present study is a longitudinal
cohort study to investigate predictors
for new cardiovascular events among
patients with CHD. Therefore, a gen-
der- and age-matched non-CHD con-
trol group was not included and the
prevalence of a severe periodontitis
among patients with CHD was com-
pared with data obtained in the
fourth German Dental Health Survey
(DMS IV). Not surprisingly, the com-
parison of patients with CHD to
matched controls without CHD
would extend conclusions. The pres-
ent study does not provide informa-
tion about whether use of aids for
interdental hygiene among individuals
without CHD reduced the risk for
CHD events at all.
In the study 118 patients were
included who reported in the inter-
view about a previous periodontitis
therapy earlier than 6 mo before den-
tal examination. Previous periodontal
therapy might lower the risk for new
cardiovascular events. Moreover,
patients with CHD were heteroge-
neous regarding their status of inter-
nal diseases. For instance, patients
with diabetes who had not yet started
any diabetic control measures were
included.
It is feasible that patients with
CHD where the concomitant internal
diseases were well treated have a
Table 4. Cox regression for the incidence of the combined endpoint (myocardial infarction,
stroke/transient ischemic attack, myocardial death) within the 1-year follow-up period
among patients with coronary heart disease. Significant data are highlighted in bold print.
Confounding variables
Hazard
ratio
95%
lower
CI
upper p values
Age 0.99 0.97 1.02 0.52
Male gender 0.65 0.37 1.16 0.15
Body mass index 0.95 0.89 1.00 0.07
Pack-years 0.99 0.96 1.02 0.43
Hypertension 0.96 0.45 2.02 0.91
Dyslipoproteinemia 0.86 0.53 1.41 0.55
Hemoglobin 0.97 0.78 1.20 0.77
Diabetes 1.51 0.90 2.56 0.12
IL-6 1.00 0.99 1.01 0.29
C-reactive protein 1.00 0.99 1.00 0.71
Creatinine 1.00 1.00 1.00 0.13
Severe periodontitisa 1.20 0.68 2.09 0.53
IL-6 c.174 GC or CC vs. GG 1.41 0.79 2.49 0.24Missing teeth 0.99 0.96 1.03 0.74
Plaque index 1.25 0.89 1.77 0.20
Number of detected various bacterial
species per individual
0.91 0.82 1.01 0.07
Frequency of tooth brushing per day 1.14 0.74 1.78 0.56
Use of floss/interdental brushes 0.19 0.06 0.63 0.01
CI, confidence interval; IL, interleukin.aSevere periodontitis: Attachment loss of 5 mm in 30% of teeth present.
Periodontitis and cardiovascular events 7
lower risk for further CHD events
than patients with untreated internal
diseases.
We investigated Caucasian patients
from central Germany. As the distri-
bution of gene polymorphisms is also
different with respect to ethnicity, our
results regarding the IL-6 polymor-
phism cannot be transferred to groups
with other ethnic affiliations.
With multivariate analyses, we tried
to identify independent risk indicators
for the incidence of the cardiovascular
endpoint. However, the results depend
very strongly on the type and number
of included confounding variables and
duration of follow-up. This could
explain different results in comparison
to other investigations.
In summary, the use of dental floss
and/or interdental brushes was signifi-
cantly associated with an adjusted
decreased HR for new cardiovascular
events among patients with CHD
within a 1-year follow-up period
whereas severe periodontitis, number
of missing teeth, the amount of
detected bacterial species and certain
IL-6 c.174 genotypes were not.Whether the use of aids for oral
hygiene actually reduces the incidence
of new cardiovascular events should be
investigated in an interventional study.
Acknowledgements
We would like to thank all patients
for their cooperation in this study.
Source of funding
The study was supported by a grant of
the Deutsche Herzstiftung, Frankfurt
am Main, Germany (F/34/08) and by
an unrestricted grant from HAIN-
Diagnostica, Nehren, (Germany).
Conflict of interest
The authors declare that they have no
conflict of interest.
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Periodontitis and cardiovascular events 9
Recommended