Prevalence of Asymptomatic Apical Periodontitis and its Association with Coronary Artery Disease in a Brazilian Subpopulation.

OBJECTIVE: The aim of the present study was to determine the prevalence of asymptomatic apical periodontitis (AAP) and its association with coronary artery disease (CAD) in a Brazilian subpopulation, and to examine the correlation of AAP with gender, age and most frequently affected dental elements.
METHODS: The data were collected from medical records of the patients (n = 1346) treated at the Specialization in Endodontics Clinic of the Federal University of Pernambuco in the period between 2003 and 2010. From each patient, the following variables were recorded: gender, age, endodontically compromised teeth, endodontic diseases diagnosed and the history of CAD. The data were analyzed using Pearson's chi-square test adopting a significance level of 5%.
RESULTS: AAP was diagnosed in 574 patients (42.6%), corresponding to 641 teeth (40.1%). Both genders (p = 0.082), and all age groups (p = 0.190) were affected similarly. The upper incisors (52.8%, p <0.001) had a higher prevalence of AAP. The patients with AAP showed 1.45 times more chance of exhibiting CAD (p = 0.307).
CONCLUSIONS: The results pointed out that the prevalence of AAP in this population was high and similar to that observed in other countries. A positive association, but not statistically significant, between AAP and CAD was found.

Introduction

Asymptomatic apical periodontitis (AAP) is defined as a chronic inflammation and destruction of apical periodontium caused in response to bacterial infection of the root canal system, which appears as an apical radiolucent area, and does not produce clinical symptoms (). Epidemiological studies on the prevalence of AAP in different countries such as Canada (), Japan (), Colombia (), Spain () e Nigeria () have revealed that this pathology is an oral health problem that affects significant proportions of people throughout the world.

In recent years, a growing number of studies have found evidence that there is an association between chronic oral infections and the development of adverse systemic health conditions (). This topic has emerged as one of the main area of research in Periodontics. Some studies have found links between chronic periodontal disease and coronary heart disease (), stroke (), acute myocardial infarct size (), cerebrovascular disease (), and development of atheromatous plaques (). Despite numerous differences between chronic inflammatory diseases of periodontal and endodontic origins, both have important characteristics in common: they are chronic infections of the oral cavity; they share a common gram-negative anaerobic microbiota () and they are both accompanied by increased local levels of inflammatory markers which may extend to systemic levels (, ). It can, therefore, be assumed that AAP is associated with the same systemic disorders that are related to the periodontal disease ().

The available scientific evidence shows that the periapical health status of patients may be directly related to their status of cardiovascular health (, -). However, the evidence remains limited. Therefore, the purpose of the present study was to evaluate the prevalence of AAP in a Brazilian subpopulation, as well as its association with coronary artery disease (CAD).

Materials and Methods

After approval by the Ethics Committee (Federal University of Pernambuco – UFPE, Recife, Brazil), information from a convenience sample of medical records of patients that had sought dental care in the Specialization Course in Endodontics of UFPE between April 2003 and March 2010 were collected. Only medical records containing full details of medical history and systemic health conditions that was self-reported during the process of medical history taking, and confirmed by an attached medical report; clinical assessments of periodontal status, including periodontal probing; and examination of the teeth referred for root canal treatment by means of pulp vitality tests, percussion and palpation, and periapical radiographs were included.

From each medical record, the following variables were recorded: gender, age, number of the endodontically compromised teeth, endodontic pathologies diagnosed, and history of CAD. AAP was diagnosed as an apical radiolucency over twice the width of the normal periodontal ligament in an asymptomatic necrotic tooth (, ). All variables were recorded by 1 observer. To exclude possible confounding factors, smoker patients, or those who were diagnosed with chronic periodontal disease or diabetes were excluded from the study.

The information obtained was tabulated and analyzed using descriptive statistics, applying the Pearson's chi-square test, adopting the significance level of 5%. The Statistical Package for Social Sciences, version 21 (SPSS, Chicago, IL) was used.

Results

A total of 1600 endodontically compromised teeth of 1346 patients were evaluated. Of those, 908 individuals were female (67.5%). AAP was detected in 641 teeth (40.1%, Table 1) and in 574 patients (42.6%, Table 2). Both genders (39.2% male and 44.2% female, p = 0.082) and all age groups (p = 0.190, Table 2) were affected similarly.

Table 1

Prevalence of asymptomatic apical periodontitis according to dental groups

AAP: asymptomatic apical periodontitis
(*):Significant association to the level of 5.0%.
(a): Using Pearson's chi-square test

Table 2

Prevalence of asymptomatic apical periodontitis according to age groups

		Patients
AGE GROUP	All	With AAP		Without AAP		p value
(years)	patients	n	%	n	%
≤18	226	84	37.2	142	62.8	p(a) = 0.190
19-29	300	133	44.3	167	55.7
30-39	334	132	39.5	202	60.5
40-49	266	124	46.6	142	53.4
50-59	165	74	44.8	91	55.2
≥60	55	27	49.1	28	50.9
Total	1346	574	42.6	772	57.4

AAP: asymptomatic apical periodontitis
(a): Using Pearson's chi-square test

In the upper arch, the incisors (52.8%) were the dental elements most affected by AAP (p < 0.001, Table 1), while in the lower jaw, the second premolars (46.2%) were the most frequently affected teeth (p = 0.187). AAP affects the maxilla and the mandible with equal frequency (40.3% and 39.6%, respectively, p = 0.770).

The prevalence of CAD was 2.3%. The patients with AAP presented 1.45 times more chances of exhibiting CAD compared to those without AAP (p = 0.307, Table 3).

Table 3

Prevalence of coronary artery disease according to asymptomatic apical periodontitis

		Patients
AAP	All	With CAD		Without CAD		p value	OR (CI 95%)
	patients	n	%	N	%
With	574	16	2.8	558	97.2	p(a) = 0.307	1.45 (0.71 - 2.95)
Without	772	15	1.9	757	98.1		1.00
TOTAL	1346	31	2.3	1315	97.7

AAP: asymptomatic apical periodontitis
CAD: coronary artery disease
(a): Using Pearson's chi-square test
OR: Odds Ratio
CI: Confidence Interval

Discussion

The primary objective of this cross-sectional study was to describe the prevalence of asymptomatic apical periodontitis, as well as its association with CAD in a Brazilian urban subpopulation by analysis of medical records of patients treated in a walk-in clinic in the Northeast of Brazil. Since the patients studied did not represent a random sample of the population, but instead constituted individuals who had sought dental treatment, the extrapolation of results for the Brazilian population in general should be made with caution.

The prevalence of AAP in this study (40.1% of teeth) was in accordance with studies conducted in other populations such as in Rabat in Morocco (), Barcelona in Spain () and Ile-Ife in Nigeria (), where AAP ranged from 38-63% of the teeth examined. However, these scores were higher than those reported in other surveys conducted in English (4.1%) (), Scottish (5,8%) (), and Kosovan (12.3%) populations ().

The discrepancies observed between the results of the above-mentioned studies can be justified by different degrees of social and economic development among populations, as well as the lack of homogeneity among the analyzed population, and the lack of standardization of evaluation methods, factors that hamper the comparison of the results from different studies.

The sample in our survey was mostly composed of female patients (67.5%). Previous research reported similar results, stating that this gender discrepancy occurs because women take care of their health and appearance better than men (). On the other hand, in our study, men and women exhibited similar AAP prevalence (39.2% and 44.2%, respectively, p = 0.082), showing that AAP is not related to gender, as previously reported by other studies (-).

Some authors such as Kamberi et al. (), Paes da Silva Ramos Fernandes et al. (), and Peters et al. () have demonstrated an increased prevalence of AAP with the advance of patient age. Although our results revealed that there was no statistically significant difference between the age groups (p = 0,190), the prevalence of AAP was higher in patients older than 60 years (49.1%), while the individuals younger than 18 years had a lower prevalence (37.2%). According to Terças et al. (), this result is expected since, with the advance of age, the tooth is exposed to caries, periodontal disease, friction and various surgical procedures that increase the incidence of pulpar inflammation.

The results of our study showed that the central and lateral upper incisors were the teeth which were most commonly affected by AAP (p < 0.001). These results can be explained by the socioeconomic status of the population sample. Since the patients were unable to pay for a subsequent prosthetic onerous treatment, they probably chose extraction of the compromised posterior teeth, and retention of the upper anterior teeth for cosmetic reasons. In addition, the central and lateral upper incisors are the teeth that are most frequently affected by trauma, which is often associated with AAP lesions ().

One of the most interesting questions that the scientific community is exploring today is the possible link between oral chronic inflammation and systemic health. Associations between inflammations of endodontic origin and cardiovascular disease are biologically plausible, given that, as in periodontal infections, the systemic dissemination of high levels of inflammatory markers may lead to subsequent deleterious cardiovascular effects (, , ).

Our study found a close, although not significant, correlation between AAP and CAD, showing that the patients with AAP had 1.45 times more chances of exhibiting CAD.

This result is in line with that obtained by Costa et al. (), who confirmed that a patient with AAP had 2.79 times higher risk of developing CAD compared to a patient without AAP.

The main limitation of our study relates to the lack of access to more detailed information on the status of cardiovascular health presented by the patients evaluated. Unfortunately, the available data were restricted to medical records containing medical information based on self-reported data during the process of medical history taking and confirmed by an attached medical report. It is, therefore, likely that the number of individuals with CAD reported in the present study has been underestimated, either due to the lack of knowledge on the part of the patients of their cardiovascular condition or due to omission of this piece of information.

Despite the limitations mentioned, the results presented here are clinically relevant because of the limited number of studies which have been published in the international literature on this topic. Thus, more research is needed into the role of endodontic infections and the development of adverse systemic health outcomes.

Conclusions

From the results obtained in this study, we concluded that the prevalence of AAP in this population was high and similar to that observed in other countries. Both genders, and all age groups were affected indistinctly. Upper incisors were affected most frequently by AAP. Moreover, a positive but not statistically significant association was found between AAP and CAD.