Periodontal diseases in adultKenyans

V. Baefum', O. Fejerskov' and RManji'^Royal Dental College, Aarhus, Denmark^Kenya Medical Research Institute, Kenya

Baelum V. Fejerskov O and Manji F: Periodontal diseases in adult Kenyans. J ClinPeriodontol 1988; 15: 445-452.

Abstract. This study comprised 1131 persons who constitute a stratified randomsample of the entire population aged 15—65 years in Machakos District, Kenya.Each person was examined for tooth mobility, plaque, calculus, gingiva! bleeding,loss of attachment and pocket depth on the mesial, buccal, distal and lingualsurface of each tooth. The oral hygiene was poor with plaque on 75-95% andcalculus on 10-85% of the surfaces depending on age. Irrespective of age, pockets>4 mm was seen on less than 20% of the surfaces, whereas 10-85yo of the surfaceshad loss of attachment > 1 mm. The proportion of surfaces per individual withloss of attachment >4 mm or > 7 mm, and pocket depths >4 mm or > 7 mm,respectively, showed a pronounced skewed distribution, indicating that in eachage group, a subfraction of individuals is responsible for a substantial pro-portion of the total periodontal breakdown. The individual teeth within thedentition also showed a marked variation in the severity of periodontal breakdown.Our fmdings provide additional evidence that destructive periodonta! diseaseshould not be perceived as an inevitable consequence of gingivitis which ultimatelyleads to considerable tooth loss, A more specific characterization of the featuresof periodontal breakdown in those individuals who seem particularly susceptibleis therefore warranted.

Key words: oral hygiene; periodontal dis-eases; loss of attachment; pockets, Kenya.

Accepted for publication 30 October 1987

The fundamental requirement for thedevelopment of rational strategies forprevention and control of periodontaldiseases (gingivitis and destructiveperiodontal disease) is a thoroughunderstanding of how these diseases de-velop and progress.

The prevailing concept is that bothgingivitis and destructive periodontaldisease are the results of long-term ef-fects of microbial activities on the perio-dontal tissues (Page 1986, Schroeder1986). Although certain doubts havebeen raised (Page 1986), it is widelyagreed that these disease entities arestrongly interrelated (Ranney 1977, Loe1986).

On a population basis, destructiveperiodontal disease is usually thoughtfo progress continuously at a relativelyeven rate (Loe et al. 1978a) althoughvariations between groups of individ-uals have been noted (Loe et al. 1986).Such data have often been interpretedas showing that destructive periodontaldisease inevitably results in a consider-able loss of teeth (Loe et al. 1978b,1986).

Recent studies on the patterns of

tooth loss in both industrialized and de-veloping countries indicate, however,that destructive periodontal disease ac-counts for a minor proportion of theteeth lost in adults even at ages beyond50 years (Ainamo et al. 1984, Bouma etal. 1985. Baelum & Fejerskov 1986), Inan adult Tanzanian population of lim-ited size, Baelum et al. (1986) showedthat not only did periodontal diseaseconstitute a minor cause of tooth lossbut also, and more importantly, that arelatively minor fraction of the popula-tion accounted for the majority of perio-dontal breakdown despite very poororal hygiene in all individuals. This ob-servation indicates that such subfrac-tions experience a much more rapidbreakdown than does the majority ofthe population.

The Tanzanian population studiedexhibited a limited number of patholo-gically deepened pockets as loss ofperiodontal attachment was most com-monly accompanied by gingival re-cession (Baelum et al. 1986). These fmd-ings implied that microbial deposits andcalculus, if left undisturbed, may notnecessarily be associated with the devel-

opment of deepened pathologicalpockets and extensive loss of attach-ment.

Inferences concerning the character-istics of sites or individuals in a popula-tion who experience rapid periodontalbreakdown can only be made based onlongitudinal studies. Although suchstudies have been conducted, the studypopulations have usually comprised in-dividuals who previously had experi-enced periodontal breakdown (Good-son et al. 1982, Haffajee et al. 1983a,Lindhe et al. 1983) or populations oflimited size and age span (Loe et al.1986).

Based on the above considerations,we have felt it necessary to investigatethe rate and patterns of progression ofperiodontal diseases in a large represen-tative sample of an adult populationwhich has limited access to dental care.The overall study design is longitudinalin nature and includes investigations ofboth clinical and laboratory par-ameters.

The aim of this paper is to report onthe cross-sectional findings at baselineof the patterns of periodontat disease in

446 Baelum, Fejerskov and Manji

Table !. The number of individuals examinedaccording to age and sex.

Age(years)

15-242S-34»-•« -45-5455-65

Total

Men

1198196

101112

509

Women

137135124114112

622

Total

256216220215224

1131

a large random sample of rural Ken-yans.

Material and Methods

The population under study was definedas all persons between the age of 15-65years living in 5 siiblocations in theNorthern Division of Machakos Dis-trict. Kenya. The population compriseapproximately 25,000 persons, predom-inantly of the Akamba tribe. The ma-jority of the population earn their livingeither as smallholders growing eoffee oras subsistence farmers growing cow-peas and maize. Except in one marketplace, there are no piped water suppliesavailable in the area, water being ob-tained from wells, springs or streams.No formal dental health care servicesare available in the area, the nearestclinic being located about 70 km southof the area. When oral hygiene is per-formed, the measures used compriseeither brushing with finger and charcoalor the use of a wooden chewing stick.The demographic, socio-economie and

general health profile of the study pop-ulation has been extensively describedelsewhere (Van Ginneken & Muller1984).

Using the largest standard deviationof the mean loss of attachment in anyage cohort observed in studies conduc-ted in Tanzania (Baelum et al. 1986), weestimated that a sample of approximate-ly 100 persons in each group would per-mit a detection of differences betweengroups in the mean loss of attachmentof at least 0.50 mm (a ^ 0.05, 1 -p =0.80). Assuming that after a period of5 years. 40% of the persons initialSyexamined would not be available, theremainder would still allow for the de-tection of differences in the mean lossof attachment of at least 0,60 mm.Therefore, the target sample sizes wereset to 100 persons in each of 10 5-yearage cohorts (15-19. 20-24, ..., 60-65).Details of the sampling procedures havebeen described previously (Manji et al,1988), For the purpose of this paper, the10 5-year age cohorts were collapsedinto 5 10-year age cohorts.

A total of 1131 persons were given aclinical examination (Table 1), Allexaminations were conducted by the 3authors in a shaded area using mouthmirrors, dental probes and periodonta!probes with natural daylight as thesource of illumination. Each person wasexamined for mobility of each toothpresent and for dental plaque, caiculus.gingival bleeding, loss of periodontal at-tachment and pocket depth on the me-sial, buccal, distal and lingual surfaces

Table 2. The proportional agreenpocket depths and calculus

:nt between examiners of recordings of loss of attachment.

ExaminerA versus B

1 versus 22 versus 31 vereus 3

ExaminerA versus B

1 versus 22 versus 31 versus 3

Examiner

! versus 22 versus 31 versus 3

3 +

11210

3 +

001

B > A b v2

31012

B > A b y2

I44

1

121114

1

193437

Agreement ofscores

776065

Loss of attachment

Agreement0

695955

Pocket depths

Agreement0

665553

Calculus

Agreementcaiculus yes/

846872

1

1267

1

1375

no

A>B by2

22

A > B b y2

100

3 +

100

3 +

-

of the teeth. Recordings on the mesiaand distal surfaces were all made fronthe buecal aspect of these surfaces. Nirecordings were made if the crown of;tooth had been destroyed by caries (i,e,only the root remaining).

Denial plaque was scored accordingto the criteria described by Silness &Loe (1964), Calculus was scored as fol-lows. Score 0: no hard deposits present;score I; supragingival calculus only:score 2: subgingival calculus (incltidedin this category were those sites at whicha rim of brownish/black calculus wasfound along the gingival margin); score3: both supra- and subgingival calculus.Loss of periodonial allachmenl wasmeasured as the distance (mm) from theenamel-cementum junction to the bot-tom of the pocket; pocket depth wasmeasured as the distance (mm) from thegingival margin to the bottom of thepocket. Due to the longitudinal designof the study, no attempts were made toremove any calculus present prior torecording loss of attachment and pocketdepth. Therefore, on sites where the en-amel-cementum junction was coveredby calculus, the position of the junctionwas determined by making reference tothe position on one of the other sites onthe tooth. Gingival bleeding was assessedafter gentle probing of the periodontalpockets. Mobility of teeth was scoredas: 0, ^ 1 mm; 1, >1 mm horizontalmobility; 2. both horizontal and verticalmobility,

1 randomly selected quadrant in eachof 30 persons who did not participatein the main study was examined for cal-culus, loss of attachment and pocketdepth by each of the 3 examiners inorder to investigate inter-examiner re-liability. Similarly, in order to investi-gate intra-examiner reliabihty, eachexaminer performed a double examin-ation of 1 randomly selected quadrantin each of 20 persons. The results ofthe inter-examiner rehability study areshown in Table 2. When allowing fordeviations between examiners of 1 mmor less, the inter-examiner agreement ofexaminer 1 versus 3 and examiner 2 ver-sus 3 for loss of attachment and pocketdepths corroborate with the results ob-tained by Badersten et al. (1984). Thereason for the agreement between exam-iners I and 2 being somewhat betteris unclear, but it is likely that these 2examiners have used the rule ''if indoubt score the lower" more frequentlythan examiner 3. This could explainwhy examiner 3 found more calculus,

Periodonial diseases in adult Kenyans

'able 3. The proportional agreement of repeated recordings of loss of attachment, pocketiepths and calculus for each of the examiners

Examiner

I23

Examiner

1

3

Examiner

123

2nd>lstby3-F 2 1

- 0 80 2 51 1 7

2nd > 1st by3+ 2 1

- 0 11

0 1 16

Agreement ofscores

888678

Loss of attachment

Agreement0 1

84 779 974 6

Pocket depths

Agreement0 1

79 1076 1373 10

Calculus

Agreement ofcalculus yes/no

898879

Ist>2nd by2 3-f

13 15 6

lst>2nd by2 3 +

000

more loss of attachment and deeperperiodontal pockets than either exam-iner 1 or examiner 2. Table 3 showsthat all 3 examiners were very consistentwith respect to intra-examiner reprodu-cibility. The agreement observed con-cerning loss of attachment was similarto that found by Glavind & Loe (1967)and Badersten et al. (1984) but lowerthan that found by Smith et al. (1970).The agreement observed for pocketdepth was similar to that observed byGlavind & Loe (1967), higher than theagreement observed by Badersten et al.(1984) and lower than observed by Smi-th et al. (1970).

The variables subjected to statisticalanalysis iri this report were defined as

"The proportion of sites per individualexhibiting ...". Hence, the unit of studywas the individual. Since the variablesconsidered did not fulfill the basic as-sumptions about normality and equalityof variances required for the use ofparametric tests (e.g.., the /"-test), analternative approach was used variouslyreferred to as the conditional x^ test formeans, or the /= analysis of variance(De Jonge 1964). This test is based onthe null hypothesis that each group in acomparison is a randomly drawnsample from a "population" whose par-ameters are defined as being those of allgroups combined.

MF MF M F M F MF15-24 25-34 35-44 45-54 55-65

m SCORE 1 ^SCORE 2 • S C O R E 3

/ 'g. 1. The distribution of surfaces withplaque. Data represent total frequency ineach age group.

MF MF MF MF MF15-24 25-34 35 44 45-54 55 65

\M ^ H SUB-ANDSUPRAGING. SUBGING. SUPRAGING.

Fig. 2. The distribution of surfaces with cal-culus. Data represent total frequency in eachage group.

MF MF MF MF MF15-24 25-34 35-44 45-54 55-65

Fig. 3. The distribution of surfaces showingbleeding on probing. Data represent total fre-quency in each age group.

Results

Plaque deposits were observed on75-95% of the surfaces present (Fig. 1).In the younger age groups, immediatelyvisible plaque deposits (scores 2 + 3)were seen on approximately Vi of thesurfaces, increasing to about Vi of thesurfaces in the older age groups. Menhad significantly more surfaces with im-mediately visible plaque deposits thanwomen (x-= 32.41; df = l;/)<0.001).

The proportion of surfaces with cal-culus increased considerably with age:from 10-20% of the surfaces among15-24 year olds to 70-85% of the sur-faces in the 55-65 year olds (Fig. 2).Subgingival calculus (score 2) was thepredominant type of calculus observed.Men had significantly more surfaceswith calculus deposits than women(/= = 48.20; df= \;p<0.00\).

Bleeding on gentle probing was seenat more than 40% of the surfaces in15—24 year olds rising to about 60-70%of surfaces in the older age groups (Fig.3). The proportion of surfaces showingbleeding on gentle probing did not differbetween the sexes ( / ' = 0.44; d f = l ;;7>0.50).

Loss of attachment affected 5-10%of the surfaces in the 15-24 year olds(Fig. 4). Most of the loss of attachmentobserved in this age group was withinthe range of 1-3 mm. In the oldest agegroup, 75-85% of the surfaces had ex-perienced loss of attachment and about'A of these surfaces presented loss ofattachment of 4 mm or more. Men hada significantly higher proportion of sur-faces with loss of attachment thanwomen (x'= 26.26; df = 1 ; / J < 0 . 0 0 1 ) .

Irrespective of age, less than 20% ofthe surfaces present had pocket depths

Baelum, Fejerskov and Manji

Table 4. The age-specific observed probabilities of finding loss of attachment if a pocket depth^ 4 mm has been found and of finding no loss of attachment if a pocket depth < 3 mm ha;been found

The observed probability of findingAge L.A. ^ 1 mm given No L.A. given(years) pocket > 4 mm pocket < 3 mm

MF MF M F M F MF15-24 25-34 35-44 45 54 55-65

Fig. 4. The distribution of surfaces with lossof attachment. Dala represent lotal fre-quency in each age group.

of 4 mm or more, and less than 3%of the surfaces presented with pocketdepths exceeding 6 mm (Fig. 5). Again,men had a significantly higher pro-portion of surfaces with pockets > 4mm than women (/ = 11.13; df = I;

/ 0 . 0 0 1 ) .Table 4 shows that the observed prob-

ability of a surface exhibiting loss ofattachment if a pocket depth of 4 mmor tnore was observed on that surfacewas strongly dependent on age as thisprobability increased from 0.34 among15-24 year olds to 0.97 among 55-65year olds. However, the probabiHty ofa surface showing no loss of attachmentif the pocket depth was 3 mm or lessdecreased with age from 0.93 among15-24 year olds to 0.22 among 55-65year olds.

Fig. 6 shows the cumulative fre-

MF MF M F M F MF15 24 25-34 35-44 45 54 55-65

4-6 MM 7-9MM

Fig. 5. The distribution of surfaces withpockets. Data represent total frequency ineach age group.

15-2425-3435-4445-5455-65

0.340.790.900.940.97

0.930.670.440.320.22

quency distribution of individuals ac-cording to the proportion of surfacesper individual with loss of attachment> i mm. > 4 mm and s 7 mm. respec-tively. Loss of attachment > 1 mm wasa very common finding as more than88% of the individuals were affected,irrespective of age. In the 15—24 yearolds, the proportion of surfaces withloss of attachment > 1 mm was rela-tively small with less than 10% of theindividuals having more than 20% o\:their surfaces with loss of attachment.In contrast, 90% of the individuals inthe 55-65 year olds had at least 50% oftheir surfaces with loss of attachment

> 1 mm.Loss of attachment >4 mm was pres-

ent in 68-100% of the individuals, de-pending on age (Fig. 6). Below the ageof 45 years, less than 20yo had morethan 30% of their surfaces affected,whereas 70% of those aged 55-65 yearshad more than 30% of their surfacesshowing loss of attachment > 4 mm.

Loss of attachment > 7 mm was onlyobserved in one person in the 15-24year group, but the prevalence increasedwith age to 80% in the oldest age group(Fig. 6).

The cumulative frequency distri-bution of individuals according to theproportion of surfaces in each individ-ual showing pocket depths > 4 mm and>7 mm, respectively, is shown in Fig.7. Pocket depths >4 mm were found in75-95% of the individuals, dependingon age. Most individuals in all agegroups had a relatively small proportionof surfaces with pockets >4 mm. butapproximately 10% had more than 15%of their surfaces affected.

Depending on age, a pocket depth of7 mm or more was found in 3-38yo ofthe individuals (Fig. 7). However, lessthan 5% had pockets > 7 mm on morethan 20% of their surfaces.

Table 5 shows the proportion of indi-viduals accounting for 75% of the total

100-i;

90

80-

20-

10

0 10 20 30 40 50 60 70 80 90 100% SURFACES/INDIVIDUAL

>50-

30- '» • . > \

0 10 20 30 40 50 60 70 80 90 100% SURFACES/INDIVIDUAL

10 20 30 40 50 60 70 80 90 lOO% SURFACES/INDIVIDUAL

Fig. 6. The cumulative distribution of indi-viduals according to Ihe proportion of sur-faces showing loss of attachment > I mm;> 4 mm; and > 7 mm, respectively, in eachage group.

Age

(years)15-2425-3435^4445-5455-65

0-3 1_

0000

Loss of attachment (%)Tim 4—6 mm

_

1122

7-9 mm

_

24253419

Total

_

1254

Periodontal diseases in adult Kenyans 449

sistently the teeth most affected by loss Table 6. The proportion of teeth showingof attachment, whereas third molars, increased mobility according to loss of at-upper canines and lower premolars were tachment and agethe teeth least affected.

Pocket depths > 4 mm were predom-inantly found on interproximal surfaces(Fig. 9). No special pattern of distri-bution of pockets > 4 mm could be di-scerned on the interproxima! surfaces ofupper teeth. In the lower jaw. however,third molars and incisors were consist-ently the teeth having the highest fre-

10 20 30 40 50 60 70 80 90 100 quency of pockets > 4 mm. lack of normality of the distribution of% SURFACES/INDIVIDUAL Overall, less than 5% of the teeth tbe variables observed in the present

present exhibited mobility (Table 6). and previous studies (Baelum et al.Mobility was almost exclusively ob- 1986), we purposely chose to presentserved in teeth with loss of attachment our data in a way which allows the di-> 7 mm but more than 65% of those versity of manifestations of periodontalteeth exhibiting loss of attachment > 7 disease to eome through. Recently, simi-

^ ^ mm did not show mobility. lar points have been raised concerning' —3 35-34 YRS the use of mean values to refiect pro-B « 35-44 YRS _ gression of periodontal disease (Lindhe:=: S : S v S °'«="'"' '" et al. 1983, Haffajee et al. 1983b).

The present data originate from a ran- The pattern of periodontal break-dom sample from a rural population down observed in the present study waswhich comprises a spectrum of econ- almost identical to that previously de-omic, social and cultural activities scribed in a smaller and less well-definedcharacteristic of rural populations in Tanzanian study population (Baelum et

% SURFACES/INDIVIDUAL Eastem Africa (Van Ginneken & Muller al. 1986, Baelum 1987). For a detailed1984). The age-span covered by this discussion on the significance of our

fig. 7. The cumulative distribution of indi- study is more comprehensive and more findings in relation to the results report-viduals according to the proportion of sur extensive than has been studied pre- ed from previous epidemiological stud-faces with pockets depths >4 mm; and >7mm, respectively, in each age group.

viously. The study therefore enables a ies, the reader is referred to these pa-characterization of the entire spectrum pers.of periodontal diseases almost through- Our data show that abundant

number of surfaces in each age group out life, albeit at present, on a cross- amounts of both soft and hard mi-with loss of attachment >4 mm. >7 sectional basis. crobial deposits are present in andmm, pockets >4 mm and pockets >7 As previously discussed (Baelum et around the gingival crevice in virtuallymm, respectively. The relatively low fig- al. 1986), several other periodontal dis- all individuals. Despite this poor oralures in most cells refiect the skewed dis- ease studies have been carried out in hygiene, the essential characteristic oftributions seen in Figs. 6, 7. populations not influenced by dental periodontal breakdown is that of a

Fig. 8 shows the distribution of loss health care. However, in most of these gradual recession of the highly inflamedof attachment according type of tooth studies, the criteria employed and the gingival margin accompanying the lossand type of surface in each age group. data presentations provided differ from of attachment. The extent of perio-Lingual surfaces generally showed more those utilized in the present study, thus dontal breakdown varies within theloss of attachment than buccal surfaces, rendering comparisons difficult. We rec- mouth so that certain teeth and siteswhich in turn showed more loss of at- ognize that our abstention from the use manifest more advanced loss of attach-tachment than interproximal surfaces, of mean values as a mode of data pres- ment than others. Despite extensive lossIrrespective of age and type of surface, entation has diminished the number of of attachment on buccat and lingualfirst molars and lower incisors were con- possible comparisons. However, due to surfaces, deep periodontal pockets were

very rare in these sites, whereas in inter-proximal sites, 4-6 mm deep pockets

Table 5. The proportion of individuals in each age group responsible for 75% of the total were more frequent. Of particular inter-amount ofJ ^^^A^^HTTm J ^A^^4^mn^^ est is that a small, but with age increas-

ing, minority of individuals is respon-sible for the major part of the loss ofattachment observed.

The finding that deepened perio-dontal pockets were mainly confined tointerproximal sites whereas loss of at-tachment was also very prevalent onbuccal and lingual sites could have sev-eral explanations. One explanation

Age(years)15-2425-3435-4445-5455-65

Proportion of individuals accounling for 75% of the totalamount of

loss of attachment (%)> 1 mm

2338526062

^ 4 mm6

22324353

^7 mm14

112131

pockets>4 mm

2934333641

: (%)2 7 mm

258

11

15

450 Baelum. Fejerskov and Manji

could be that vigorously performed oralhygiene procedures may cause gingivaltissue recession as a result of mechanicalirritation (Sangnes & Gjermo 1976).The amounts of plaque and calculus ob-served on buccal and lingual sites, how-

ever, do not support this suggestion (Ba-elum 1987). As we see it, a more likelyexplanation is found in the suggestionthat microbial plaque has a certainrange of effectiveness in generatingbone loss (Page & Schroeder 1982). As

15-24 YR 25-34 YR 35-44 YR 45-54 YR SB-K YR

INTERPROXIMAL

• t - 3 MM

Fig. 8. The distribution of loss of attachment according to type of tooth and type of surface.Data represent total frequency in each age group.

the bone thickness is generally much lesin buccal and lingual sites as comparecto interproximal sites, this could explaiiwhy pocket formation is apparently favoured in interproximal sites.

It could be argued that those individ-uals who apparently are less affected b\periodontal breakdown are individualswho have already lost their affectedteeth. However, this is not very likely.Only I edentulous person was identifiedand a house-to-house survey revealedthat the rate of edentulousness of per-sons aged 20 to 65 years was less than0.3% (Manji et al. 1988). Moreover,even in the oldest age group, more than50% of the individuals had at least 26remaining teeth and 90% had at least16 remaining teeth (Manji et ai. 1988).

From a holistic viewpoint, it seemsthat in humans it is possible to have amassive microbial accumulation alongthe marginal periodontium for a periodof some 20 years (from 6 to 25 years ofage) without there being any significantsign of irreversible breakdown except ata few sites in a minority of individuals.This appears to be the case, despite themarginal gingiva being markedly in-flamed throughout this period of time.Even at a late age, a substantial numberof individuals remain almost unaffectedby clinical loss of attachment despite thepresence of severe gingivitis.

Although this statement appears tobe a truism, our findings indicate a needto reconsider the concepts of the etiol-ogy and pathogenesis of destructiveperiodontal disease. Certainly, our find-ings support the view that gingivitis maynot be a "harbinger of impending perio-dontal destruction'" (Page 1986) andthat the "continuous disease" conceptof destructive periodontal disease needsreevaluation (Socransky et al. 1984). Asall strategies for treatment and preven-tion are governed by these concepts (So-cransky et al. 1984), their reconsider-ation is particularly important in orderto derive more rational strategies for theprevention and treatment of destructiveperiodontal breakdown.

It is apparent from the present datathat within each age cohort, there existssubfractions of advanced break-downers. The size of these subfractionsincreases with increasing age. However,until the longitudinal data are available.we are not able to determine whetherthose individuals who experience thisrelatively severe breakdown at an earlyage are also included in the severely af-fected subfractions at a later age. The

Periodonlai diseases in adult Kenyans

Fig. 9. The distribution of surfaces with periodontal pockets according to type of tooth atype of surface. Data represent total frequency in each age group.

though it is conceivable that mass-prophylactic campaigns may changesome of these explanatory factors, it re-mains a question whether such cam-paigns will, in turn, lead to a decreasein the prevalence of destructive perio-dontal disease. Thus, although gingivitisdecreased (Douglass et al. 1983), nosimilar trend was observed for theprevalence of periodontal pockets.

Taken altogether, the present findingsemphasize the need to further ourunderstanding of the development andprogression of gingivitis and destructiveperiodontal disease in order to be ableto develop more appropriate strategiesfor the treatment and prevention ofthese diseases.

Acknowledgements

This paper constitutes a report of thePrimary Oral Health Care Projccl, ajoint project of the Kenya Medical Re-search Institute and the Royal DentalCollege. Aarhus, Denmark, which issupported by DANIDA (IO4.Kenya.4).We would also like to acknowledge herethe assistance of The Ministry of Health(Kenya); Colgate-Palmolive (East Af-rica) Ltd.; East African Industries Ltd.;and The Kenya Army. Our thanks aredue to the Director, Kemri, for per-mission to publish this paper.

recetit finditigs by L6e et al, (1986) indi-cate that such identification may bepossible, but due to the limited numberatid age-span of the population in theirstudy, this question needs further atten-tion. In a subsequent paper, we willpresent a detailed characterization ofthe clinical manifestations of perio-dontal breakdown in these apparentlymore susceptible individuals.

Although our data are of a cross-sectional nature, the above consider-ations suggest that the strategy of choicefor the control and prevention of perio-dontal diseases in this populationshould not necessarily involve the tra-ditional approach of regular, pro-fessional removal of all hard and softniicrobial deposits in al! individuals (Pi-hlstrom et al. 1983. Lindhe & Nyman1984). Quite apart from the inordinatecosts of a strategy based on such prin-ciples on a population basis (Manji &Sheiham 1986). our data indicate thatonly a subfraction of the populationneed intensive professional care to pre-vent tooth loss as a result of periodontaldisease.

From the point of view of costs, on apopulation basis an alternative strategycould be that of mass-prophylactic cam-paigns to improve periodontal self-care.Recent studies have indicated that somepopulations presently experience a de-cline of the prevalence of gingivitis,which is associated with an improve-ment of the oral hygiene situation (Dou-glass et ai. 1983). These improvementshave been ascribed to factors such ashigher education levels, higher income,increased dental care utilization, in-creased use of antibiotics, and decreasein smoking (Douglass et al. 1983). Al-

Zusammenfassung

Parodonlalkrankheiten bei erwachsenen Keni-anernAn dieser Studie nahmen 1131 Personen teil- eine geschichtete Stichprobe der 15-65-jah-rigen Gesamtbevolkerung im Distrikt Ma-chakos in Kenia, Bei jeder Versuchspersonwurde die Zahnlockerung, die Plaque, derZahnstein. die Blutungsbereitschafl der Gin-giva, der Attachment vert ust und die Taschen-tiefe an der mesialen. distalen und hngualenOberflache eines jeden Zahnes untersucht.Die orale Hygiene war mangelhaft, mil Pla-queansammlungen an 75—95% und Zahn-stein an 10-85% der Zahnoberflachen - je

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Badersten, A., Nilveus. R. & Egelberg, J, (1984) Reproducibility of probing attachment levelmeasurements. Journal of Clinical Periodontology 11, 475-485.

Baelum, V. (1987) Pattern of periodontal breakdown in adull Tanzanians. Scandinavian Journalof Denial Research 95, 22i-228.

Baelum. V. & Fejerskov, O. (1986) Tooth loss as related to dental caries and periodontalbreakdown in adult Tanzanians. Community Dentistry and Oral Epidemiology 14, 35 J-357.

Baelum. V,. Fejerskov, O. & Karring, T (1986) Oral hygiene, gingivitis and periodontalbreakdown in adult Tanzanians. Journal of Periodontal Research 21. 221-232-

452 Baelum. Fejerskov and Manji

nach dem Alter. Vom Alter unabhangig wur-den an weniger ais 20% der Oberflachen S 4mm-Taschen konstatiert und an 10-85% warder Attachmentvcrlust > 1 mm. Das Verhalt-nis zwischen Oberflachen pro Versuchspersonund Attachmentveriust von > 4 mm oder > 7mm; sowie Taschentiefen von > 4 mm bzw.> 7 mm zeigte eine ausgesprochen schiefeVerteilung und liess daniii erkennen, dasseine Teilgruppe jeder Altersklasse von demhaupsachlichen Antcil des parodontalcn Ab-baus betroffen ist. Innerhalb der Gebisse wa-ren gleichtalls bedeutende Unterschicdezwischen der Schwere des parodontalcn Ab-baus einzelner Zahne vorhanden. tjnsere Re-sultate iassen weiteres Beweismaterial fiir dieThese erkennen. dass die destruktive Paro-dontalkrankheit nicht als eine unvermeidbareFoige der Gingivitis zu betrachten sei. dieunbedingt zu betrachtlichem Zahnverlustruhrl, Eine ins Einzclnc gchcndc Beschrci-bung der Merkmale des parodontalen Ab-baus bei schcinbar besonders anfalligen Per-sonen, erscheint darum von hohem Stellen-

Resume

Maladies parodontates chez les aduttes duKenyaLa presente etude portait sur i 131 f>ersonnesqui constftuaient un echantillon aleatoirestratifie de la totalite de la population de15-85 ans dans le district de Machakos, Ke-nya. Les parametres suivants onl ete exami-nes chez chacun des sujels: mobilite dentaire,plaque, tarlre, saignement gingival, perted'attachc et profondeur des poches sur lesfaces mesiales. veslibulaires, distales et hn-guales de chaque dent. L'hygiene buccale etaitinsutTlsante, !a plaque couvrant suivant Page75-95% des surfaces et le tartre 10-85% dessurfaces. Independamment de Page, on neconstalait de poches > 4 mm que sur moinsde 20% des surfaces, tandis que 10-85% dessurfaces presentaieiil une perte d'attache > 1mm. La proporlion des surfaces/individuayani respectivement une perte d'atlache > 4mm ou > 7 mm, el une profondeur de poches> 4 mm ou > 7 mm presentait une distribu-tion d'une asymelrie marquee, cc qui indi-quait que, dans chaque groupe d'age, uneproportion notable du total de la destructionparodontaie pouvait eire mise ,sur le compted'un petit nombre d"individus. On notait aus-si une variation marquee de la severite de ladestruction parodontaie au niveau des diffe-rentes dents. Nos resultats fournissent unepreuve suppiementaire que !a maladie paro-doniale destructrice ne doit pas etre regardeecomme une consequence inevitable de la gin-givite, aboutissant a des pertes dentairesconsiderables. II esl done justifie de cherchera etablir une caracterisation plus speciflquedes elements de la destruction parodontaiechez les sujets qui semblent y etre particulie-rement predisposes.

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Address;

Viheke BaelumDepartment of PeriodontologyRoyal Dental CollegeVennelyst BoulevardDK-8000 AarhusDenmark

ntology