Cojtnnunity Dent. Oral Epidemiol. H)78; 6: 97-10:^

(Key word-'*: denial raiifs, fliolof^y: denial plaque: m'urooriian

Actual caries developmentcompared with expected caries activity

J . RUNDKC.REN AND T . ERK'.SON

Departtticnt oj Cartotogy. Eaculty oj Oilontotogy. Utiiversity oj Utticd. Utticd. Sivedett

Aii.s-i-RAcr - l n 18 s(-lioolboys, 16 years o ld , llic a(-tual car ies cle\-elopment d u r i n g 1 y e a r was

( o m p a r e d w i l h Ihe ex iK ' i ted (-aries ac t iv i ty w h i c h was p r e d i c t e d from c x a l n a l i o n s of fonr

se lec lcd tests; (1 ) the bu f l e r ( a p a c i l y , (2 ) the l i te r of Streptococcus niulatts hi s t i i iu i l a ted

w h o l e sa l iva , (3 ) cliiii(-al e v a l u a t i o n of r a t e of ]5laqiie f o r m a t i o n , a n d (-1) a q u a n l i t a l i o n of

a sa l iva ry a g g l u l u i i n r e a c t i n g w i l h a s e ro lype c s t r a in ol i". mutans. .Xccordins;- to pri ' \-ious

e x p e r i e n c e s t h e e s t i m a t e d \-aliic for ea( h fa(-|(ir \\-;is ( l ass i l i ed lor e a c h i n d i v i d u a l e i t he r as a

n e g a t i v e (cari(- .s- | j rovoking) or as ;i n o n - n e g a l i v e factor , l h e score of n e g a t i v e fac tors cou ld

Ihus va ry b(-lvveen 0 a n d 4 for e a c h i n d i v i d u a l . A good r e l a t i o n s h i p was obsen ' ( -d b(- t \ \cen

the ca r ies i n c r e m e n t d i u i n s 1 yea r a n d t h e svini of t h e scores f rom the lesls r e p r e s e n t i n g

cxi )cc tcd car ies act i \- i ly. T h i s o b s e n - a t i o n i n d i c a t e s the possibi l i ty of sele(-tinn- llic mosl (-;iries

s u s c e p t i b l e i n d i v i d u a l s in a p o p u l a t i o n b;- nsiiig l h e four p ; i r a i ne t c r s . ,\ scl<-(-tion can be

m a d e from Iwo or t h r e e of the tests bu t then ihc d e g r e e of d i f l e r e n t i a l i o n IK-COIUCS lower .

N o p a r a n i e l e r c o u l d s ingly be used as a n i n d i c a t i o n of l h e p o t e n t i a l ( a r i e s ;i(-ti\-it\- in t h e

i n d i v i d u a l lesl .

(.Accepted jor publication 27 Novetnber t977)

fn an epidemiologic stndy'' it was lotind that in.spite of a general prophylactic program iiu'lndingregular fluoride treatment and instruction, about25 % of a poptilation still show high caries activity.As shown in an extensive study' on the effect of oralhygiene on dental caries, a careful oral Iiygiene pro-gram performed by dental auxiliaries leads to a.strongly reduced number of new caries .surfaces.

Endogenous lactors, as the salix'ary flow rate,buffer capacity of saliva, activity of nuLScles in-volved in the tnasticatory ftmetion, and salivary fac-tors which may redttce bacterial retetition in theoral cavity, can be regarded as determining the po-tential caries activity in an individual. The actualclinical caries activity is determined by exogenousfactors in combination with endogenous factors.Unfavorable valties of endogenous parameters willincrease the ri.sk for a high actual caries activity butmay bt- compensated for by a careftil diet, propei-oral hygiene habits, the n.se of antibacterial agents,and fluoride trealment. The clinical caries activitywill depend on the degree of compoisation.

To be able to give |:)roper prophylactic treatment

to risk group patients, procedures must be axailablelor prediction of ]X)tential caries activity and selec-tion of earie.s-prone individuals. The relationshijjbetween caries inerement or earies frequency andsingle factors of probable etiologic importance hasbeen studied iti a mimbrr of inxestigations"-'-"-'''-111, IS. -ji. rj.-i

Due to the nmltifactorial character of the cariesdisease, single factors may not lia\-e a dominant rolein caries cle\'elopment in a population. In the pres-ent investigation, therefore, we wanted lo sludy thepossibility of increasing the information about thepotential caries actix'ity b)- using a combined e\'al-nation of several parameters a.sstimed to l")e relatedto caries development. A combination of four fac-lors were tested for their value in the prediction olcaries develojjiuent during a test period.

MA FERIAL AND METHODS't\'st persons - Two groups, each of 10. 16-year-old lest

persons, wer(- selected Irom the dciit;il records of 71 school-

boys. Fell sliidcnts Avith less lliaii 4 DMl 'S were selected

for OIU- grou|) and 10 with more than 27 D M l ' S for ihc

98 RuNDl'.GtiEN AND I'jRtCSON

other group. Two subjects belonging lo lhe group wilh highDMFS-S(-or(-s dropj)cd out during lhe study.

The boys were n(;wly treated by ihcir regular denlistsand carried no carious lesions at lhe baseline registration.These children had all visited the same dental clinic oncea y(;ar since the age of 7 and at every visit ihey had beensubjected to extensive prophylaetic treatmenl by iheir den-tists and by auxiliaries Irained in jjrophylaxis. 'Lhis treat-ment included information and instruction abonl oral hy-giene measurements, plaque removal by auxiliaries andfluoride trealmenl; topical twice a year and rinsing atschool every 14tli day.

Clitiical examitiatioti and sartipling procedures - Onthree occasions during Uu- t('st year - at the starl, after 6months, and after 1 year - a careful registration of dental(aries was made wilh mirror and prob(- and four bitewingradiograjihs. This registration was made at 4;00 p.m. aflera careful elcaniufj of llu- teeth (for cleaning ])ro(;ednre seeRate oj plaque jortnatioti below).

PARAMETERS USED FOR ESTIMATIONOF CARIES ACLIVfTY'Phe concentration oj the salivary agglutinin which inducesaggregation of S. mutatis, strain KPSK 2, was determinedill resting whole saliva'. A numerical value for a concen-Iratioti of less ihan O.t)85 was regarded as low and asre|3reseiuiiig a negative factor in this context.

The rate oj plaque jormatton was estimated clinically16 hours after a careful polishing of llu; teeth. The pol-ishing was carried out in Iwo steps. In the first step asuspension of pumice in 2 % sodium fluoride solution wasused with a Robinson brushcup. In the seeond were used

a rubber cup and a fluoride-containing |x)lishing paste(Jodka fluor®, Jodkaliklora, Gothenburg, Sweden). A dis-elosing solution, 1 % basic fuehsin, was then ajiplied lo theteelh and plaque still remaining was removed with arubber cup and the Jodka paste. Special altenlion wasgiven to the leeth which were to be included in the e\'al-iialion of plaque formalion Ihe nexl morning. The par-licipanls were then told to avoid all oral hygiene niea-surcnicnls until after the next examination 16 hours later.At lhis examination new visible bacterial colonies on thebuccal surfaces of the maxillary right premolars were reg-islrated using llu- same disclosing solulioii as Ihe day be-fore. Discoloralions of pits and cracks were not regarded asnew plac|U(-.

The rate of plaque formation eslimau-d in this way was(onsidered high and a negative fa(-tor when new plaquewas deleeled on lhis o(;(;asion. f he rale was considered lowwhen no plaque was found'^.

I he concetttratiott oj S. tnutatts in whole stimulatedsaliva was measured after cultivation on mitis salivariusagar containing bacitracin". Tbe agar plales were ineu-bated anaerobically at 37°C for 1 day and then placed atroom teinperalure aerobically for 2 days. 'Fhe eslimalion of6\ mutans was based on colony morphology. An incidenceof more than 2t)0,000 eolony forming unit.s/ml was arbi-trarily regarded as a negative factor.

The bujjer capacity of stimulated whole saliva was de-termined according lo ERICSSON^', lhe final pH of a mix-lure of 1 ml of saliva and 3 ml of 5 liiM hydrochloric acidwas deterniined after aerali(jn for 2t) min lo remove carbondioxide. A final value of 5.3 or less was regarded as anegative hxeUn^.

Table 1. Numerieal values for the investigated paraiiiet(-rs from the 1-year examination. Values eonsidered negative art-found below dolled lines

SubjectNo.

83

185

12171496

1074

16

z11

Imn

Buffer(-apacily

8.097.797.607,457.257.027.016.506.356.025.5.5r>.5+

5.3t)4.044.003.443.403.25

Subje(-tNo.

510

113

n1

1747

12146

18102

lf>16

.S'. mutatisper ml

00

2,00018,000tit),00080,00t)

184,000

274,000280,000300,00050t),000550,000()t)0,000630,t)00670,0t)t)820,000910,000

1,600,000

SubjectNo.

3141811

521

15171210689

164

147

Aggregation(-apacily

0.1580.131O.Ill0.1050.1030.0910.085

0.0820.0780.0780.0690.068tl.O620.0620.062O.t)460.0450

SubjectNo.

567i9

10

23

1314

11

121415161718

Rate of plaqueformation

slowslowslowslowslowslow

(fast)(fast)(fast)fastfastfastfastfastfastfastfastfast

Aetttal earies dcvelofjinent 99

CO

Q A

u.O 2

CO

I'abh- 2. Distrilnilion of de(-ayed siirf;u-es (DS = 37) be-tween the negative—non-negativ(- exaliiation lor each factor

D INUMBER OF NEGATIVE VALUES

Fiij 1. Dislribulion of negative-, values for the evaluatedfactors b(-tweeii the lesl individuals. E\-aluations made atthe r2-iiioiith registralion. O]K-n bars denote individualswith lc.s.s ihan 4 D M F S al lhe baseline regislralion. Dottedbars dcnole individnals wilh more ihan 27 D M F S at thebaseline registralioii.

RESULTSIn Table 1 are given the titinierical values for theinvestigated parameters for each subject at the 1-year examination. Negative evaluations arc madefor values below the dotted lines.

A normal statistical distribution is seen of thenegative factors in the population (Fig. 1). Thereis a tendency to a larger ntimber of negative factorsin the group with high caries development beforethe start of the .study. This relationship between thepotetitial caries activity as evaluated from the num-ber of negative factors and DMFS score groups wasfound both at the 6-montli registration and at the1-year registration. The distribtition ol negative fac-tors at the baseline registration was not as differ-

Evaliialed faclors Negali\-e Non-negali\-c

,5. tnutattsBuffer capacity.Aggregation capaciURale ol ]jlaque formation

29122633

825114

entiated. In the whole grotip 37 new decayed sur-faces were developed during the test year (Table2) . Twenty-nine of these were combined with anegati\'e evaluation for S. itt tit ans whereas eightcavities were not. Approximately the same relation-ship was found lor aggregation capacity and rate ofplaque formation. Buffer capacity showed an in-verse relationship. When each factor is analyzed inrelation to the caries score for eaeh individual wefind (Table 3) that the negative or non-negativeex'aluations of single factors generally do not give asufficient basis for prediction of caries.

The stim of negative factors for each individtialis compared with the aclual caries dewlopnientduring the test year as shown in Fig. 2. The sub-jects with low numbers of negative factors devel-oped fewer new caries lesions than the stibjeels withhigh numbers of negative factors. The gronp withhigh initial DMFS-scores quite clearly developedmore caries lesions than the low l^MFS-scoregrotip. When the caries increment is plotted againsttriplet-combinations of negative factors, i.e. one fac-tor at a time is excluded, we can compare the prog-

Table 3. Distribution, according lo lhe negative or non-negative evalualion for each factor, of individuals with zero lofive new caries lesions

Factor cvahiat(-d No. of individualsNew c;iries lesions

.S'. mutans

Buffer (;apacity

Aggregati(jn (-ajjacity

Rate of plaf|iic

formation

11 wilh

7 wilh

6 wilh

12 with

I 1 wilh

7 with

12 with

() with

neg.

non-neg.

neg.

non-neg.

neg.

non-neg.

neg.

3

2

(I

5

4

1

1

1

3

2

2

1

3

3

0

1

1

0

0

1

1

3

I

1

3

')

2

3

1

0

0

1

I

0

1

3

0

2

1

3

t)

3

non-neg.

100 RuNtiEGREN AND ERICSON

zO

UJ 0Z D

0 1 2 3 4

NUMBER OF NEGATIVE VALUESl'ig. 2. Number of new cari(;s lesions during the tesl yearcoinpan-d wilh llu- miiiib(;r of iu;galivc values for llic fourevaluated factors, fujr explanation of symbols sec; Fig. 1.

toLU

toUJ

UJ

Z 0

0 1 2

NUMBER OF NEGATIVE VALUES

Fig. 4. Relationship between cari(-s increment and numberof negative values for only Iwo evaluated factors; .V. mu-tatts and aggregatiott capacity. Vor (-xplaiiation of .sj-mbols.s(-c Fig. I.

nostic value of the different factors. In Fig. 3 is.shown the .situation when buffer capacity wa.s ex-cluded. A weaker correlation betweeti caries incre-ment and the number of negative factors was ob-tained with all three-factor combinations.

When two factors at a time are compared withthe develo]3nient of new caries lesions, the degree ofdifferentiation becomes even lower, as shown inl''ig. 4 where buffer capacity and rate of plaque for-mation were excluded.

DISCUSSION

Tlie results of the present study indicate that in thepatients in whom we pt-edicted a high potential ear-

to 5

Z

(7)UJ

- • 3

to

UJ

Z D

7-:

rr

Iv*

•S

•jij:yy,:•:•":

%

* : • r0 1 2 3

NUMBER OF NEGATIVE VALUESl'ig. 3. Relalioiisliip betwe(-ii the number of nc-w cari(;s h--sions and lhe nuinber of negative- vahies when ihc eval-uation of one fa(-tor, bujjer capacity, is (-xcluded. For cx-planatioti of symbols se(; l''ig. 1.

ies activity, higher scores of new DS were found.Mfchanisms for colonization of looth surfaces by

caries-inducing microorganisms have been ratherwidely .studied during the last years'*-"-'"-'•'-'". Thesalivary concentration of microorganisms which]Drefer solid surfaces as habitat would prestimablybe i-elated to their frequeney in dental plaque.HOUTE Ik GREEN'" found that a successful inocula-tion of ,S'. mulans was related to the size of the in-oculum, la the present study the salivary ntmiber of.S'. mutans representing a high potential caries ac-tivity was chosen according to this finding. Fur-thermore, the consistent patterns of localized colo-nization for S. mulans' will make a repi-esenlativesampling of dental plac^ue for bacteriologic analysishazardous. The salivary titers of S. tnutans mighttherefore reflect the amount of S. mulans colonizing'the dental surlaces and the chances for recoloniza-tion after a thorough toothcleaning jjrocedtire. In astudy by KEOCK & KRASSE' ' , where saliva sampleswere collected from a population with plaque ofundefined ages, generally higher salivary numbersof S. niutans were, reported than we lotind in thepresent investigation. LOESCUE, ROWAN, STRAFFON

& Loos"' reported that tlict-e was no correlationbetween saliva titers of S. mulans and caries devel-opment. In the present study a weak (orrelationwas fotmd between salivary -S\ mntans values andcaries increment during the Le.sl year. Howev(>r, incombinalion wilh other factors it contributes to avalid eslimation of potential caries activity.

The salivary tiler of an agglutinin reacting withserotype e strain.s of S. ?nutans has been reported in

Aetual earies develofiitiettt 101

a highly standardized clinical study to be inverseh'related to the rate of plac|ue formation''. The ag-glutinin titer would reflect the rate of recolonizationof cleaned tooth surfaces. In the present study ear-ried out tmder le.ss controlled conditions a weakercorrelation is observed but in a conceited evaluationof several factors, they seem to add to the informa-tion on potential caries activity.

Because of the central role ol acids in the ioriua-tion of caries lesions a high bufler capacity of salix'acan be assumed to have a caries-preventive effect.In spite of the multifactorial nature of the cariesdisease correlations bt-tween buffer capacity andcaries prevalence have been reported'"'-'".

In the ]3resent study low btiller capacity is notwell correlated to the amount of new dental cariesin each individual. However, as seen in T'able 3 lessnew caries is de\'eloped in patients with a good biil-fer capacity. In the group of patients with a high(non-negative in Table 3) value for bufler capa-city a larger number of ]3atients were caries freeduritig the test year.

In this grotip of tesl subjects generally the oralhygiene standard was high. It was therefore likelythat the rate at which new dental plaque appearedon a cleaned toolh surface would be better relatedto caries develoijment than would a plaque scoretaken on a given occasion. The rate of plaque lor-ination a.s evaluated in this study varies a lot in a]3opulation and is obviously in the present iinesti-gation well correlated to caries development. At ahigh rate a cariogenic situation is present for a con-siderably longer time.

It appears that a combination of several tests lorestiniation of caries activity could be ol elinical usein the selection of lisk groups, i.e. ]Datients with highpotential caries activity. It is Important to realize-that a high potential caries activity must not nec-essarily be related to a high actual caries develop-ment. Factors like oral hygiene, dietary habils andpossibly other triggering factors will have a strongeffect on this relationship. In a study like the pres-ent one it may be difficult to know whelher a lackof correlation, when pre.sent, between the evalua-tions of potential caries acti\'ity and the actual car-ies development is due to such triggering factors orto a minor importance in caries etiology of the se-lected parameter. Judging from the results ol thesum of the four factors it appears that the la(-tors.selected are related to caries de\'eio]:)inent.

riie selected parameters may not be ideal forepidemiologic .screening for risk patients but con-firm the idea that several factors should be tised inevaluation of potenlial caries activity. It is neces-sary to lind simpler ways for the selection proce-dure. It may be observed that the single factorwhich had the b;\sl relalionshij) to caries de\-elop-nient was the clinical evaluation of rate of plaqueformation. This parameter also has the advantageof requiring no speeial equipment or personnel.

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1. & FRILL. I..: Flu- (H-curreii(-(- of (ertaiii "earies-

102 RUNDKOKEN AND ERICSON

inducing" strej)loco(;ci in human dental plaque mate-rial. With special referen(;e to fr(;qii(-ncy and activityof caric^s. Arch. Oral Biol. 1968; 13: 911-918.

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salivary aRglulinins on bacU-rial colonizalion of loothsurfac(-s. Caries Res. 1976; 10: 113-122.

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Address;

Departmettt oj CariologyEaculty oj OdontologyUniversity oj UntedS~90l 87 UrtieaSweden