Summary

The present epidemiological study is derived from arandom sample of 322 residents of the Porto area, aged30–39 years. Prevalence of apical periodontitis andresults of endodontic treatment were evaluated fromorthopantomograms, available from 179 of a total of197 individuals attending for examination. The resultsindicated a prevalence of apical periodontitis in 27% ofthis population. The quality of a majority (54%) of the69 root fillings observed were found to be inadequate,(i.e. short and/or poorly condensed), but only 15 (22%)of the endodontically treated teeth presented with apicalperiodontitis.

Keywords: apical periodontitis, endodontic treatment.

Introduction

Epidemiological studies on adult oral health from theScandinavian countries have documented high preva-lence of apical periodontitis (30–50%) and success ratesof endodontic treatment performed by general practi-tioners varying between 60 and 75% (Molven 1974,Allard & Palmqvist 1986, Hugoson et al. 1986,Petersson et al. 1986, Eckerbom et al. 1989, Eriksen1991, Eriksen & Bjertness 1991, Eriksen et al. 1995).This is inferior to that generally obtained from specialtyclinics (Strindberg 1956, Grossman et al. 1964, Kerekes& Tronstad 1979, Ørstavik et al. 1987). High prevalenceof apical periodontitis has also been documented in aDutch (deCleen et al. 1993), a Swiss (Imfeld 1991) andan American (Buckley & Spångberg 1995) study, whilstinformation from other countries is lacking. Studies onadult oral health have been performed in Portugal(Meyer et al. 1983, Almeida et al. 1987, Meyer 1990,Almeida et al. 1990, 1991, Marques 1994), but none of

them have reported on the prevalence of apicalperiodontitis and quality and results of endodontic treat-ment.

In the scientific, endodontic literature, reports basedon selected cases and studies of advanced techniquesand new materials are dominating (Eriksen 1991).Endodontic epidemiology is, however, important inorder to give a complete picture of endodontic diseases,their treatment and treatment outcome in differentsocieties. The aim of the present study was therefore torecord the prevalence of apical periodontitis and qualityand results of endodontic treatment in an adultPortuguese population.

Material and methods

The original sample comprised 322 individuals, 30–39years of age and living in the Porto area. This samplewas randomly drawn from electorate lists in 1990,constituting approximately 0.5% of the population.From the original sample, 197 individuals were avail-able for the clinical investigation (61%). Of the non-attendants, 65 invitations were returned because ofunknown addresses, and 35 refused to participatebecause of lack of interest. From the last 25, no responsewas received. Orthopantomograms (OPGs) (Fig. 1) andbite-wing radiographs were obtained from 179 individ-uals (56%). The main reasons for not having OPGs takenwere technical difficulties, pregnancy and lack of time.With these limitations considered, the sample might berepresentative of the 30–39-year-olds in the Porto area.

The endodontic investigation was part of a compre-hensive oral health study performed at the dental school(Faculdade de Medicina Dentária) in Porto during 1990(Marques 1994). Presence of an apical periodontallesion was evaluated from the OPGs (Fig. 1) using thePeriapical Index (PAI) (Ørstavik et al. 1986) fordocumentation of the severity of the lesions (score 1–5for increasing size and severity). For teeth with morethan one root, the highest score was allocated to the

International Endodontic Journal (1998) 31, 161–165

Prevalence of apical periodontitis and results of endodontictreatment in an adult, Portuguese populationM . D. M A RQ U E S a , B . M O R E I R A a & H . M . E R I K S E N b

aDepartment of Preventive Dentistry and Department of Endodontics, Faculty of Dentistry, University of Porto, Porto,Portugal; and bDepartment of Operative Dentistry and Endodontics, Faculty of Dentistry, University of Oslo, Oslo, Norway

© 1998 Blackwell Science Ltd 161

Correspondence: Professor M. D. Marques, Faculdade de MedicinaDentária do Porto, Departamento de Medicina Dentária Preventiva,Rua Dr Roberto, Frias, P-4000, Porto, Portugal.

tooth. An intraobserver reliability test was performedbased on a double scoring of 23 OPGs. This test indicateda consistent scoring level with high intraindividual relia-bility (Table 1).

The status of each tooth was recorded as ‘not rootfilled’, ‘pulpotomy’ (pulp chamber filled), and ‘rootfilled’. In addition, retained roots were recorded. This lastcategory was a frequent finding in the present sample.The quality of the endodontic treatment performed was classified in four categories. ‘Adequate’, indicatingproperly filled root canals terminating 3 mm or less fromthe radiographic apex; ‘voids’, indicating voids andporosities in the root filling; ‘short’, when the root fillingterminated more than 3 mm from the apex; and ‘long’,indicating a surplus of root filling material visible peri-apically. Short and incomplete root fillings were fre-quently recorded together. For endodontically treatedteeth, the quality of the root fillings was correlated withthe prevalence of apical periodontitis.

Results

Table 2 gives an overview of the main findings. Becauseof the low number of root-filled teeth, the three cate-gories: voids, short and long, have been groupedtogether as ‘inadequate’ in the presentation of theresults. The 179 individuals studied had a total of 4446teeth (mean 23.9 including third molars). The mean

value for the total sample of 197 individuals was 24.8.Forty-seven of these individuals (26%) presented withone or more teeth with an apical periodontal lesionclearly identified in the OPGs (PAI-score 3–5), whilst 39(22%) had one or more teeth endodontically treated(Table 2). The number of endodontically treated teethpresent was 69, including three pulpotomies (Table 3).The number of teeth with an apical periodontitis (PAI-score 3–5) was 87, including 28 in association withretained roots (Table 3). Fourteen participants presentedwith two or more retained roots with an apical perio-dontal lesion, in addition to other signs of neglected oralhealth, indicating a skewed distribution of retained rootsin the sample. These individuals all reported irregulardental visiting habits, but other oral health and socialparameters did not differ significantly from the meansample values.

Fifteen of the 69 endodontically treated teethpresented with an apical periodontitis. Four of the 69teeth could not be evaluated due to the inferior quality ofparts of the OPGs. Overall, the results indicated a successrate for the endodontically treated teeth of 78% (Fig. 2).Of the 65 endodontically treated teeth eligible for evaluation, 30 (46%) had adequately filled roots (wellcondensed and terminating 3 mm or less from theradiographic apex). Twenty-six (87%) of these showedno or only minor deviations from normal periapicalstructures, and may be considered as successful treat-ments. Of the 35 teeth having one or more signs ofinferior quality of the root fillings, 11 presented with anapical periodontitis (31%), whilst 24 (69%) had normal

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© 1998 Blackwell Science Ltd, International Endodontic Journal, 31, 161–165

Fig. 1 Orthopantomogram showing several teeth with incompleteendodontic fillings and a remaining root (45), but no apparent apicalperiodontitis present.

Table 1 Results from double PAI-scoring of 551 teeth from 23orthopantomograms

First score

1 2 3 4 51 532 0 0 1 1

Second 2 0 2 0 0 0score 3 1 0 1 0 0

4 0 0 0 2 05 3 0 0 0 8

Table 2 Prevalence of endodontically treated teeth and teeth withapical periodontitis based on orthopantomograms amongst 30–39-year-old Porto citizens

Number of subjects examined 179

Individuals with endodontically treated teeth(including 3 pulpotomies) 39 (22)

Individuals with apical periodontitis (PAI- score > 2) 47 (26)Number of teeth present in the sample 4446Number of endo-treated teeth 69 (1.5)Number of teeth with apical periodontitis

(including 28 remaining roots) 87 (2.0)Endodontically treated teeth with apical periodontitis 15 (0.3)

aFigures in parentheses are percentages.

Table 3 Individual distribution of root fillings and apical periodontitisamongst 30–39-year-old Porto citizens

Number per individual Total

8 6 5 4 3 2 1Root fillings 2 1 3 11 22 69Apical periodontitis 1 2 1 2 3 7 31 87

periapical structures despite the inferior quality of theroot fillings (Fig. 2).

Discussion

The present investigation is derived from a randomsample of 30–39-year-olds from the Porto area.Although the final attendance for the radiographicevaluation was only 56% of the initial sample of 322(70% if the 65 individuals without known addresses areignored), there was no apparent selection bias present.The mean number of remaining teeth amongst the 179individuals with OPGs was 23.9, which is very close tothe original sample value of 24.8.

There is some uncertainty linked to periapical diag-nosis from OPGs, with a possible underestimation of thereal values. However, Ahlqvist et al. (1991) indicatedgood correlation between OPGs and intraoral radio-graphs, and a slight overestimation was recorded in arecent study on 35-year-olds (Eriksen et al. 1995). It istherefore probable that the validity of recording peri-apical status from OPGs is acceptable.

The intraindividual reproducibility performed showedidentical scores for 545 of the 551 teeth included. Thelargest discrepancy was observed amongst score 5s dueto uncertainties linked to remaining roots with com-bined marginal/apical periodontal lesions (Table 1).

Prevalence of apical periodontitis was 27% in thisadult, Portuguese population (Table 2). This is close tothe values found in Scandinavian populations of similarage (Molven 1974, Hugoson et al. 1986, Petersson et al.1986, Eckerbom et al. 1989, Eriksen & Bjertness 1991,

Eriksen et al. 1995). When considering the number ofteeth affected (87 out of a total of 4446), this gives 2.0%including 28 remaining roots. A skewed distribution ofapical periodontitis was observed with a few individualspresenting with many apical lesions (Table 3). Thesefigures indicate that apical periodontitis is a prevalentoral disease.

When considering the prevalence, quality and resultsof endodontic treatment, the present data demonstratedthat 22% of the present sample had one or more teethwith a root filling (Table 2). This is lower than that foundin several Scandinavian (Molven 1974, Hugoson et al.1986, Petersson et al. 1986, Eckerbom et al. 1989,Eriksen & Bjertness 1991, Eriksen et al. 1995) and oneDutch (deCleen et al. 1993) investigation, where theprevalence of individuals with endodontically treatedteeth has been reported to be around 50% in this agecohort.

The quality of endodontic treatment is inferior to thatreported in many epidemiological studies (Molven 1974,Allard & Palmqvist 1986, Hugoson et al. 1986,Petersson et al. 1986, Eckerbom et al. 1987, Eckerbom et al. 1989, Eriksen 1991, Eriksen & Bjertnes 1991,Petersson 1993, Eriksen et al. 1995) (Fig. 1). Incom-pletely obturated roots with porosities and absence ofgutta-percha cones were commonly registered. On theother hand, well condensed root fillings were also afrequent finding, indicating substantial variations in the quality of endodontic treatment in this population(Figs 1 and 2).

Despite the quality problems encountered in thepresent study, the results of endodontic treatment weresurprisingly good. An overall success-rate of 78% isequal to or better than reported in most other epidemio-logical studies, and the results seemed to be lessinfluenced by quality fluctuations in endodontic treat-ment than is commonly found (Eriksen 1991) (Fig. 2).The most probable explanation for this may be thatextraction is a more commonly accepted treatment for apical periodontitis in Portugal than in theScandinavian countries. Thereby, teeth with apicalperiodontitis and unsuccessfully treated teeth may havebeen extracted and therefore excluded from observationin the present study. This assumption is supported by thefact that the average number of remaining teeth waslower in the present population than in similarScandinavian populations (Marques et al. 1994). Thetendency to extract teeth with apical periodontitis mayalso have resulted in a high proportion of vital pulp extir-pations, improving the overall prognosis of endodontictreatment (Strindberg 1956).

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© 1998 Blackwell Science Ltd, International Endodontic Journal, 31, 161–165

PAI–scores 1-2

PAI–scores 3-5

100%

50%

Totalsamplen = 65

Adequatelyfilled

n = 30

Inadequatelyfilled

n = 35

Fig. 2 Success of endodontic treatment according to quality of the rootfillings evaluated in Portuguese 30-39-year-old patients. Presence of adistinct periapical radiolucency (PAI-score > 2) (Ørstavik et al. 1986)was used as criterion for apical periodontitis/failure.

The treatment profile and dental visiting habits arealso different from Scandinavia (Marques et al. 1994).All the individuals with two or more remaining rootswith apical periodontitis were attending their dentist onan irregular basis only, indicating that attitudes toextractions are of importance to the present findings. Onthe other hand, remaining roots without any sign ofapical periodontitis was also a frequent finding. Togetherwith the high frequency of inadequately obturated teethwith normal periapical condition, this may suggest that factors related to biology and/or techniques andmaterials used may be of relevance for the resultsobserved.

In Portugal, the most commonly applied endodontictreatment procedures, until recently, included the use ofarsenic-containing, mummifying pastes in vital casesand potent, usually formaline-containing antiseptics forantibacterial dressing of the pulp chamber and canals.Endodontic treatment was never completed in onesession. Therapeutic pastes such as N2 (Sargenti 1971)and iodoform-containing pastes were most commonlyapplied, frequently without complete removal of pulpaltissue and the use of gutta-percha points. During the lasttwo decades, a gradual shift toward treatment utilizingmore tissue-compatible agents and standardized prin-ciples (Ingle 1961, Kerekes & Tronstad 1979) hasoccurred. However, it is likely that a majority of the rootfillings evaluated in the present study represent thetraditional approach.

It has recently been suggested that one of the majorreasons for failures in endodontic treatment is related tocoronal leakage and re-infection of the root canal system(Saunders & Saunders 1990, Ray & Trope 1995).Although the frequent use of toxic compounds inendodontic treatment in Portugal does not comply withmodern principles of infection control and antibacterialtreatment (Sundqvist 1976, Bystrøm 1986), they mighthave reduced coronal reinfection. This may in partexplain the surprisingly good periapical status of endo-dontically treated teeth shown in the present investiga-tion, despite the inferior technical quality of the treat-ment performed. In this context, it is also interesting tonote that the overall best results documented byStrindberg (1956) was obtained in pulpectomies usingdevitalizing, arsenic or paraformaldehyde-containingpastes.

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