Xylitol chewing gum in caries prevention: a field study in children

Xylitol chewing gum in caries prevention: a field study in children

A R T I C L E S A s th e prevalence o f dental caries decreases in industrialized n a tio n s like th e U nited States, it sim u lta n eo u sly incre...

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A R T I C L E S

A s th e prevalence o f dental caries decreases in industrialized n a tio n s like th e U nited States, it sim u lta n eo u sly increases in developing n a tio n s a n d T h ird W orld countries. T h e decrease in the W est is attributed to increased use o f fluorides, b u t the increase in developing countries has been exp la in ed by a n increase in the co n su m p tio n o f sugar. A s this in fo rm a tio n continues to p ro p el researchers to fin d sucrose substitutes, x y lito l has been singled o u t as a proposed sucrose replacem ent. T h e q uestion tackled by th is study was: Can the daily use o f chew ing g u m c o n ta in in g xy lito l increase the efficacy o f the ex istin g caries-preventive m easures n o w regularly used fo r 11- to 15-year-old children in m ost industrialized western countries?

Xylitol chewing gum in caries prevention: a field study in children P au li Isokangas, D D S Pentti Alanen, M A , P h D , D D S Jaakko T iekso, D D S Kauko K. M akinen, P h D , M A

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h e e p id e m io lo g ic a l p ic tu re of dental caries has changed d u rin g th e p a s t d ecade. T h e la te s t epidem iological d a ta 1 confirm two tre n d s: r a p id ly in c re a s in g p re v a le n c e of caries in m any developing countries an d sim ultaneous decrease of dental caries in m ost industrialized countries. D ental c a rie s seem s to c o n c e n tra te in a d i ­ m in ish in g pro p o rtio n of the in d u stria l­ ized p o p u la tio n .2’6 T h e teeth of ab o u t o n e -fifth of each age g ro u p in in d u s ­ trialized countries co n tin u e to decay at a considerable rate.7-9 C hanges in the prevalence of a m u l­ tifactorial disease like dental caries are difficult to explain. In developing co u n ­ tries, however, the increase in caries has been ex p lain e d th ro u g h an increase in th e c o n s u m p tio n of s u g a r .10 11 T h e decrease in caries in industrialized nations has been considered p rin c ip a lly a co n ­ sequence of increased use of fluorides.1217 C om m on factors in nearly all countries w ith ca rie s r e d u c tio n h av e b e e n th e widespread use of dentifrices co n tain in g flu o rid es an d the a v a ila b ility of better

preventive systems. F u rth e rm o re , co m ­ pare d w ith the situ a tio n 10 years ago, the lower num ber of cariogenic m icroor­ gan ism s (S trep to co ccu s m u ta n s, lactoglobal bacilli) in children has at least p artially explained the observed reduction in caries p re v a le n c e .18 T h e p re v a le n c e of o th e r streptococcal diseases such as scarlet fever an d rh e u m a tic fever has also d eclin ed w ithin the past decade.19 E vidence su g g ests th a t re d u c tio n in the frequency of the use of sucrose leads to decreased caries activity in h u m an s.2022 T h is in fo rm a tio n h as g iv e n rise to attem pts to replace the sucrose, especially in p ro d u c ts co n su m ed betw een m eals, w ith sweeteners th at are less cariogenic. T hese sw eeteners in c lu d e ce rtain sugar a lc o h o ls (p o ly o ls), su c h as s o rb ito l, m a n n ito l, an d x y lito l. R ecen t d a ta on the effect of xylitol on the gro w th and m etabolism of S m u ta n s have stren g th ­ ened the case for xylitol as a p o ten tial sucro se s u b s titu te .23,24 S ev eral h u m a n ca ries tria ls , som e of th e m u n d e r the au s p ic e s of th e W o rld H e a lth O rg a ­ n iz a tio n (W H O ) a n d c a r rie d o u t by

in d e p e n d e n t research team s, have su g ­ g ested th a t x y lito l p r o g ra m s m ay be reg ard ed as p o te n tia l ca ries-p rev en tiv e m ethods u nder co n d itio n s in w hich caries prevalence an d caries incidence are h ig h o r are increasing, a n d also in areas w here there are considerable nu m b ers of c h il­ dren w ith u ntreated caries.25 29 M ore re se a rc h is n e e d e d , h o w ev e r, p a rtic u la rly o n ways of im p ro v in g the efficacy of e x is tin g p r e v e n tio n m e th ­ ods.30,31 T h is study asks: C an daily use of a c h e w in g g u m c o n ta in in g x y lito l increase the efficacy of the existing cariespreventive m easures now regularly used for 11- to 15-year-old ch ild ren in m ost in d u stria liz ed w estern countries? Study su b je c ts w ere fro m Y liv ie sk a , a r u r a l co m m unity in n o rth F inland. T h e decision to perform the study in F in la n d w as re la te d to th e c o n d itio n s prev ailin g in the F in n ish h ealth centers, o ffe rin g th e o p p o r tu n ity to te st th e efficacy a n d a c c e p ta b ility of ca riespreventive agents u n d er actual conditions. Because of the sim ila rities betw een the U n ited States an d F in la n d w ith regard JADA, Vol. 117, August 1988 ■ 315

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to the d ietary h a b its32 an d caries prev­ a le n c e ,17’33 the results o b ta in e d in this study should be applicable to the U nited States an d other industrialized countries. T h e W H O chew ing gum program s are c o n sid ered successful in H u n g a ry an d o th er T h ird W orld countries.25 29’34'35 Methods and materials

Background and subjects T h e Ylivieska xylitol study spanned from 1982 th ro u g h 1985 at the Ylivieska H ealth C enter in n orthern F inland. T h e health c e n te r services th e to w n o f Y liv ie sk a (p o p u latio n 12,500). T h e subjects in the study were born in 1970 and 1971, and were included in organized dental health program s and dental care on an an n u al b asis sin ce 1972. A ll d e n tin a l ca rio u s le s io n s (D 2 ) p re s e n t in p rim a ry a n d p erm an en t teeth were restored. According to the recom m endations of the N ational Board of H ealth of F inland, the fluoride m easures were: flu o rid e tablets a d m in ­ istered w ith o u t su p e rv isio n ; d en tifrice co n tain in g fluoride adm inistered starting

by fluoride measures. All ch ild ren p a r­ ticip atin g in the field study lived w ith in the same co m m u n ity w ater-su p p ly sys­ tem , w here the flu o rid e c o n c e n tra tio n in the w ater was low (< 0.1 ppm ). A ll 11- to 12-year-old c h ild re n (n = 366) w ho w ere fifth- an d six th -g rad e rs in th e fa ll of 1982 in th e Y liv ie sk a elem entary schools acted as test subjects. T h e xylitol (X) g ro u p (n = 212) an d the control (C) g ro u p (n = 154) were form ed by sc h o o l classes. In ea ch class, th e children belonged either to the X or C g ro u p . T h is a rra n g e m e n t p a rtly m in ­ im ize d th e u se of x y lito l p ro d u c ts in the control g roup, to w hich no chew ing gum was provided as p art of the study. T h e Y livieska trial was a field study by its nature; the experim ental arran g e­ m ents excluded the p otential for a d o u b le­ blin d study. It was also n o t feasible to carry o u t a ll c lin ic a l e x a m in a tio n s as b lin d recordings. At the baseline stage, w hen they all were at the sam e school w ith th e 11- to 1 2 -y ear-o ld c h ild r e n b e lo n g in g e ith e r to the X o r C g ro u p only, the e x a m in in g d en tist was aw are

Consequently, all final examinations and the examination of the initially 12-year-old children at the 1-year stage could be performed on a blind basis. from the age of 5 (w ith out supervision); biweekly rinses w ith 0.2% N aF solution at schools for 7- to 13-year-old children, supervised by a dental nurse, a govern­ m ent em ployee w ho visits schools twice a week teaching oral hygiene; and topical fluoride treatm ents at the h ealth center o n e to tw o tim e s ea ch year. C a ries prevention also included the use of fissure se ala n ts in the first m o lars before the trial. N o sealants were used du rin g the trial. T h e c h ild r e n c h o se n fo r th is stu d y w ere a p p o rtio n e d in to a x y lito l g ro u p (X gro u p) an d a control gro u p (C group). All carious lesions re q u irin g treatm ent (D 2 ) d u r in g th e tria l w ere resto re d a t th e a n n u a l c h e c k u p s in b o th g ro u p s. In th e to w n o f Y liv ie sk a , th e ca ries p re v a le n c e fig u re s of c h ild re n aged 6 to 17 years have been slightly better than th e m ean prevalences in F in lan d . T h e efficacy of the xylitol gum program was, thus, tested in a situation in w hich good results have already been achieved, m ainly 316 ■ JADA, Vol. 117, August 1988

o f th e g r o u p in g o f th e su b je c ts. T h e situ a tio n was altered in the year w hen the children reached 13 years, an d were thus transferred to the same ju n io r h igh school. At th a t p o in t, the classes w ere re-formed, and each new class random ly c o n ta in e d p u p ils b e lo n g in g to e ith e r the X or C group. T h e ex am in in g dentist could n o longer be aw are in w hich g ro u p the child had originally belonged. C on­ se q u e n tly , a ll fin a l e x a m in a tio n s an d the exam ination of the in itially 12-yearo ld c h ild re n at th e 1-year stag e co u ld be perform ed on a b lin d basis.

Chewing gum use As a vehicle for x y lito l, ch ew in g g um (5.4 g) c o n ta in in g this carb o h y d rate as the only sweetener was used. T h e xylitol c o n te n t o f each p iece w as 64.7%, c o r ­ re sp o n d in g to 3.5 g xylitol. T h e o th er in g r e d ie n ts w ere g u m b ase (29.87%), glycerol (1.98%), p ep p erm in t o r spearm int o il (0.45%), ta lc u m (0.50%), a n d w ate r

(1.30%). T h e gum was distributed at the schools to the children in the X g ro u p by a d e n ta l n u rse. T h e c h ild re n were instructed to chew the g um three times each day: after breakfast, as an afternoon sn a ck , a n d a t d in n e r. T h e m a x im u m daily xylitol dose was thus approxim ately 10 g, a n d th e c h e w in g tim e a b o u t 5 m in u te s . A ll in s tr u c tio n s c o n c e rn in g n u tr iti o n a n d o ra l h y g ie n e a t h o m e rem ained unchanged, and were identical in the X an d C groups. T h e parents of the children were fully instructed about th e use of th e x y lito l g u m , a n d w ere asked to supervise the use a t hom e. A d e n ta l n u rse c o n tro lle d a n d reg istered com pliance at schools regularly.

Clinical examination T h e su b je c ts w ere e x a m in e d in itia lly an d at 1-year in terv als by five d en tists a t th e h e a lth cen ter. A ll re g is tra tio n s were carried o u t after supervised toothb ru sh in g , an d were entered on a record form th at d id n o t m en tio n either group. D u rin g the study, the caries status was follow ed in the p e rm a n e n t teeth o n ly , alth o u g h the status of the prim ary teeth w as re g is te re d a t ea c h e x a m in a tio n . T h r o u g h o u t th e stu d y , a ll caries re g ­ istrations were m ade w ith o u t know ledge of earlier exam inations. T h e health care center’s codes and criteria for caries were m odified according to the requirem ents of W H O .36 T h e resu lts of clin ic al ex a m in a tio n s a n d o f o th e r o ra l r e g is tr a tio n s w ere evaluated through: m easurem ent of interan d in tra -e x a m in e r v a ria tio n in caries rec o rd in g ; c o m p a riso n betw een X an d C g ro u p s w ith reg ard to a ll m easu red variables at baseline ex am in ation , in c lu d ­ ing gender; analysis of data on dropouts in com parison w ith those rem ain in g in th e study; c o m p a riso n of caries in c re ­ m e n ts ex p ressed as d ecayed (firs t an d seco n d d eg rees se p a ra te ly ), ex tra c te d , an d filled te eth /to o th surfaces—location of surface, type of caries, an d by to o th — in the X an d C groups; com parison of increm ent rates between g roups in terms of surfaces at risk; com parison of caries increm ents of teeth eru p ted d u rin g the 2-year study; an d q uestionnaire presenta­ tions. Before the end of the 2-year followu p, two groups were form ed on the basis o f th e to ta l ca rie s e x p e rie n c e a t th e b aselin e ex a m in a tio n : all 11 year olds w ith D M F T > 5, an d all 12 year olds w ith D M FT > 7, were allocated to the high-risk g ro u p (34 children in the h igh

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caries-active xylitol gro u p and 36 in the h ig h caries-active control group).

Statistical methods In co m p ariso n of cross-sectional in fo r­ m a tio n , the M ann-W hitney U -test was used. In com parison of caries increm ents, the covariance analysis was used to adjust

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for baseline prevalence between groups. T h e differences between groups in incre­ m en t values were, how ever, also tested by the M ann-W hitney U-test. T h e P ear­ s o n ’s x 2 test w as u se d in c o m p a ris o n of th e d is tr ib u tio n s . T h re e le v els of significance were selected: P < .001, P < .01, P < .05. T h irty children p artic­ ip a tin g in the study as subjects or controls were random ly draw n for the exam iner variability analysis, w hich was done once d u rin g the 2-year study. T h e five dentists e x a m in e d the c h ild r e n in 2 days; 15 c h ild re n w ere d raw n a g a in at ra n d o m to be reexam in ed after 2 weeks by the sam e d en tists. T h e re su lts w ere based o n in f o rm a tio n of 30 c h ild re n in the inter-exam iner analysis a n d of 15 children in the intra-exam iner analysis. N o specific c a lib r a tio n w as p e rfo rm e d b efo re th e study. T h e reproducibility ratio by Shaw and M urray37 was used for each exam iner an d each p air of exam iners. T h e inter­ exam iner ratios of the five dentists ranged b e tw e e n .12 a n d .30 a n d th e in t r a ­ e x a m in e r r a tio s b etw e en .05 a n d .18. T h e s e r a tio s w ere w ith in th e ra n g e observed in other studies.37,38

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s ig n if ic a n tly in a n y of th e v a ria b le s m easured. T h e girls of the X g ro u p had s ig n if ic a n tly (P < .05) less c a rie s as m e a su re d by th e fo llo w in g v a ria b le s: D 2 -teeth, D 2 M F-teeth, D 2 F teeth, and D 2 surfaces. T h e DMFS increm ents an d increm ent rates for AD 2 MFS scores were calculated for b oth groups. In the X group, AD 2 MFS was 1.1 an d AD 1- 2 MFS was 1.3, an d the ra te of in c re m e n t w as .9 a n d ra te 1-2 was 1.1. In the C g ro u p , the increm ent scores were 2.0 an d 2.3, an d the rate scores 1.7 an d 2.0, respectively. T h e differences between the X an d C groups, m easured w ith AD 2 MFS an d rate scores, were h ig h ly significant (P < .001), w hereas m easured w ith AD 1- 2 MFS an d rate 1-2 scores, the differences were significant (P < .01). A n aly ses of ea c h in d iv id u a l to o th sh o w ed th a t th e seco n d m o la rs w ere am o n g the m ost susceptible teeth. T h e preventive effect of xylitol was also m ost clearly seen in second m o la rs in b o th bo y s a n d g irls , b u t th e re w as n o d is ­ tin c tio n betw een the second m o lars of th e m a x illa a n d m a n d ib le (F ig 1). G e n e ra lly , in a ll to o th g ro u p s, th e X g r o u p h ad lo w er in c re m e n ts th a n th e C group. T h e caries increm ent for the occlusal, b uccolingual, and ap p ro x im al surfaces— as well as for sm ooth surfaces and fissures an d pits by scores ADi 2 M FS—are given in Figure 2. T h e occlusal surfaces were the m ost su scep tib le surfaces to caries, a n d th e p re v e n tiv e effect o f x y lito l chew ing g um was m ost clearly seen on these surfaces. Based on interview s after 1 an d 2 years, th e su b je c ts w ere p la c e d in to th re e su b g ro u p s acco rd in g to the n u m b e r of X g um pieces used daily. Figure 3 shows

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F ig 2 ■ (A) T w o -y e a r m e a n c arie s in c re m e n t by location o f surface an d (B) by type o f caries:*, P > .05; **, P > .01; ***, P > .001.

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Isokangas-Others : XY LITO L CHEW ING GUM IN CARIES PREVENTIO N « 3 1 7

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th a t c h ild re n w h o u sed a n average of th re e p ie ce s o f g u m p e r day h ad s ig ­ nificantly less caries th an those w ho used fewer. T h e interview s also show ed th a t th e X a n d C g ro u p s d id n o t d iffe r significantly in the use of fluoride tablets a n d d e n tifric e s . T h e la tte r w as u se d re g u la rly by 90% of the ch ild ren ; o n ly less th a n 7.6% u sed f lu o rid e ta b le ts regularly. T h e frequency of the consum p­ tio n o f sw eets w as n o t s ig n ific a n tly affected by the use of X gum . T h e num ber of su b je cts w h o left th e X g ro u p w as 10% in 2 years. T h e m ost com m on reasons for leaving were related to m oving aw ay from school or com m unity, poor coop­ e r a tio n (overuse of g u m ), a n d loss of interest.

Three-year follow-up In th e 2-year fo llo w -u p , th e ca ries reduction between the high-caries groups was 49% an d 43% between the total groups, b u t th e p re v e n tiv e b e n e f it w as m o re n o ta b le d u r in g the th ir d year (F ig 4). T h e ca ries in c re m e n t level w as stab le in the high-caries X group, b u t the level in c re a se d in th e h ig h -c a rie s C g r o u p d u rin g the th ird study year. T h e highca ries X g ro u p h a d lo w er in c re m e n ts th a n the C g ro u p in all to o th groups, b u t the caries-preventive efficacy of xylitol w as e s p e c ia lly n o ta b le in m a x illa ry incisors. T h e preventive effect was also seen in second molars. In addition, the d ifferences betw een g ro u p s were m ore pron o u n ced in m axillary prem olars than in m a n d ib u la r p rem o lars, w hereas the s itu a tio n in first m o la rs w as o p p o site to th a t observed in p re m o la rs (Fig 5). T h e 3-year in c re m e n t o f th e d iffe ren t to o th surfaces w as an a ly z ed by scores D 1- 2 MFS. T h e difference between groups w as h ig h ly s ig n ific a n t (P < .001) for all types of surfaces except th e buccolin g u al surfaces, in w hich the difference was significant (P < .01). Discussion S ev eral r e p o r ts 39-42 c la im th a t a g u m base (alth o u g h stim u latin g salivary flow) does n o t increase or decrease caries, but th a t th e effect is r a th e r ca u se d by an added therapeutic agent or the sweetener p re s e n t. T h u s , in th is s tu d y a p la in c h e w in g g u m c o n tr o l g r o u p w as excluded. In addition, it is n o t feasible to expect the children to habitually chew three pieces of unsw eetened an d u n fla ­ vored g um base daily, 5 m inutes per piece, fo r 2 to 3 years. B ecause of p ra c tic a l 318 ■ JADA, Vol. 117, August 1988

rea so n s ( d is tr ib u tio n of p ro d u c ts a n d th e ir ev e n tu al use by the C g ro u p ), it was not possible to random ize the o rig in al participants in to X and C groups. T h e c h ild re n w ere in ste a d a s sig n e d to the resp ectiv e g ro u p s a c c o rd in g to sch o o l classes. In spite of this, som e C -g ro u p subjects used xylitol chew ing gum . T h is was a com m on occurrence in the W H O c o m p arativ e field tria ls as w ell.43 T h e tria l w as ch a ra c te riz e d by a w eak n ess typical of field studies—the experim ental a r r a n g e m e n ts d id n o t a llo w fo r th e b a s e lin e r e g is tra tio n s , n o r th e 1-year follow -up ex am in atio n s of the in itially 11 year olds on a blin d basis. All other re g is tra tio n s w ere p e rfo rm e d w ith o u t know ledge of the d is trib u tio n in to the X and C groups.

T h e p rev en tiv e reg im en by ch ew in g gum co n tain in g xylitol was well accepted by the subjects, ab o u t 90% regularly using tw o to three pieces p er day. S im ilarly, 90% of the present subjects in the X and C groups used fluoride dentifrices w ithout s u p e rv is io n . T h e e v a lu a tio n o f th e acceptability of chew ing g um in W H O field studies was also encouraging. T h e subjects of the X a n d C g ro u p s were in clu d ed since 1972 in a co m p re­ hensive dental care system, an d the same caries-preventive program . T h e subjects of both groups were also sim ilar in other b ack g ro u n d factors: flu o rid e content of d rin k in g water, use of fluoride-containing d e n tifric e s a n d tab lets, a n d freq u en cy of use of sweets. In the p resen t study, th e c o n d itio n s fo r h o m o g e n e ity of g ro u p s44,45 were met as closely as possible u n d e r th e circ u m sta n ce s p re v a ilin g in field studies. In the C g ro u p , the c o n ­ su m p tio n of sweets an d g um co n tain in g x y lito l a v a ila b le a t su p e rm a rk e ts a n d kiosks was so m in o r th at it had no cariespreventive significance.

Clinical effects In c o rp o ra tin g x y lito l g u m usage as an ad d itio n to the norm al caries prevention p ro g ra m of the h e a lth center caused a h ig h ly s ig n ific a n t caries re d u c tio n , a prevention benefit m ore notable in girls th a n in boys. T h e caries re d u c tio n in th e boys betw een the X a n d C g ro u p s was 33% (D 1- 2 MFS used as a m easure), w h erea s th e sam e fig u re fo r the g irls was 55%. T h e difference was at least partly caused by the more reg u lar use of gum by the girls. T h e difference in incidence scores on the basis of gender is perhaps also e x p la in e d by th e d iffe re n t tim es of to o th e ru p tio n betw een the genders, a lth o u g h th e c o n s is te n t use of ca ries in c re m e n t rates effectively assesses the true caries increm ent in a biostatistical sense.46 G irls m ay show a b etter effect b ecau se of lo w er b a s e lin e v alu es a n d a slightly larger g ro u p th an control. D u rin g the study, new carious lesions a p p e a r e d m o st f re q u e n tly in seco n d m olars of subjects aged 11.5 to 13.5 years. T h e new lesions were m ainly in fissures an d pits. T h is fin d in g was n o t a surprise, as o th e r stu d ie s h av e sh o w n th a t th e seco n d m o la rs are a m o n g th e m o st su sc ep tib le teeth a t th is age, an d th a t p re v e n tio n b ased o n f lu o rid e s is less effective on fissure caries th an on caries of sm ooth surfaces.47-50 P it and fissure caries ca n n o t be com ­ pletely prevented by red u cin g exposure

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to p la q u e an d sugar51; other additio n al p re v e n tiv e m e asu res are need ed . T o prevent fissure caries, inclusion of xylitol in caries-preventive p rogram s seems to offer an a d d itio n a l preventive m ethod. In this study, xylitol decreased the caries incidence in the fissures of second m olars by 42%, w ith o u t the use of fissure sealants. In the collaborative W H O studies, a m ore p ro n o u n ce d caries red u c tio n was achieved w ith a com bined fluoride and xylitol regim en (alternatively a m ixture of xylitol an d sorbitol) than w ith fluoride a lo n e .30-32,34,35 In th e p re s e n t tr ia l, a su p p le m e n tal 45% caries red u ctio n was ac h ie v ed w ith th e a d d itio n o f x y lito l to the reg ular preventive program , based m a in ly o n f lu o rid e s . T h e c o n c e p t of concerted approach seems appropriate. T h e caries-preventive ben efit for the children w ith high-caries incidence was m ore notable d u rin g the th ird study year th a n d u r in g th e f ir s t 2 years. T h e increased increm ent a t this age in highrisk c o n tro l subjects is m a in ly caused by p ro x im al caries. T h is trend is in line w ith e a r lie r o b s e rv a tio n s .50 In th e X g r o u p , th e in c re m e n t level r e m a in e d stable. Regardless of the basic prevention, th e m a x illa ry in c iso rs w ere su b je c te d to decay in the high-risk children after ag e 13. H o w ev er, th e u se of x y lito l m a in ta in e d the m a x illa ry in ciso rs v ir­ tually intact. T h e regular use of xylitol g u m s, in a d d itio n to b asic p rev e n tiv e measures, resulted in a significantly lower increm ent of caries th an obtained in the c o n tro l g r o u p re c e iv in g o n ly b a s ic prev en tio n . As the ac ce p tab ility of the g u m w as g o o d a lso fo r th e se w eekly m o tiv ated h ig h -caries risk in d iv id u als, x y lito l g u m s m ay be c o n s id e re d a n effic ie n t a d d itio n a l m e th o d fo r caries prevention. Summary A 2-year study was ca rrie d o u t o n 11to 12-year-old c h ild re n w ith m o d erate a n d decreasing caries prevalence. T h is study so u ght to determ ine w hether gum co n tain in g xylitol used in com bination w ith b a s ic ca ries p r e v e n tio n w o u ld im p ro v e the efficacy of the p rev e n tio n com pared w ith a control g ro u p practicing b asic p re v e n tio n on ly . T h e fin a l p a r ­ ticipants in the study were 324 children p la ce d in to a x y lito l g ro u p (n = 172) a n d a co n trol g ro u p (n = 152). After 2 years, th e AD 2 MFS in c re m e n t w as 1.1 in the xylitol group an d 2.0 in the control g ro u p . T h e effect o f x y lito l w as m ost clearly observable in second m olars, the

m o st su sc e p tib le te e th . D ifferen ces betw een the groups were h ig h ly signif­ icant, show ing th a t the co m b in atio n of xylitol gum an d fluoride usage resulted in a better protection against caries than th e b asic p re v e n tio n ( flu o rid e u sag e) alone. A separate 3-year trial was perform ed in subjects at h ig h risk for dental caries. T h e 3-year increm ent of caries was highly significant, 3.4 in the X g ro u p an d 8.7 in th e C g ro u p . T h e caries re d u c tio n between the caries-active X an d C groups was 51%. T h e caries reduction was better (66%) than d u rin g the first 2 years (49%). T h e decrease in caries in b o th follow u p exam inatio n s was achieved th ro u g h th e activ e a c tio n o f x y lito l g u m , n o t by a reduction in the frequency of intake of sucrose sweets.

----------------- J'AOA ----------------A dditional ta b u la r m aterial as w ell as data analysis in f o r m a tio n is a v a ila b le fro m D r. M a k in e n a n d can be sent o n request. T h e a u th o rs th a n k H ellas, a d iv is io n o f L e a f, In c , B a n n o c k b u r n , IL , w h o provided the xylitol gum . I n f o r m a tio n a b o u t th e m a n u f a c tu r e r s o f th e products m entioned in this article is available from the au th o rs. N either the au th o rs n o r the A m erican D e n ta l A ss o c ia tio n h as an y c o m m e ric a l in te re s t in the products m entioned. Dr. Is o k a n g a s is c h ie f d e n ta l o ffice r, Y livieska H e alth Center, Ylivieska, Finland, an d is w ith the I n s titu te o f D e n tistry , U n iv e rs ity o f T u r k u , a n d D r. A la n e n is a ss o c ia te p ro f e s s o r , c o m m u n ity dentistry, In stitu te of D entistry, U niversity of T u rk u , T u rk u , F in lan d . Dr. T iesko is in stru c to r in cariology, a n d Dr. M akinen is professor of bio ch em istry and dentistry, School of D entistry, U niversity of M ichigan, A nn A rbor, M I 48109. Address requests for reprints to Dr. M akinen. 1. W o rld H e alth O rganization. T e c h n ic al report series 713: p re v e n tio n m e th o d s a n d p ro g ra m m e s for o ral diseases. G eneva, Sw itzerland, 1984. 2. M arth aler, T . Selective In te n siv p ro fy la x e zur w eitgehenden V erh u tu n g von Zahnkares, G ingivitis u n d P a r o d o n ti tis b e im S c h u lk in d . S chw eiz M onatsschr Z ahnm ed 85:1227-1240, 1975. 3. von der Fehr, F.R. Evidence of decreasing caries p re v a le n c e in N o rw a y . J D e n t R es (S p e c ia l Issue)61:1331-1335,1982. 4. T h y lstru p , A.; Bille, J.; a n d B raun, C. Caries prevalence in D anish children liv in g in areas w ith low a n d o p tim a l levels of n a tu ra l w a ter fluoride. C aries Res 16:413-420, 1982. 5. H u g o s o n , A.; R y la n d e r , H .; a n d K o c h , G . L o n g itu d in a l study of d e ntal caries in ind iv id u als in Jo n k o p in g , Sweden, aged 15 years in 1973 and 20 years in 1978. C om m unity D ent O ra l E pidem iol 13:100-103, 1985. 6. N ordblad, A. P atterns and indicators of dental decay in th e p e rm a n e n t d e n titio n o f c h ild re n and adolescents, thesis. Proc F in n D ent Soc 82, S u p p l X II, 1986. 7. Bay, I. Id e n tific a tio n of c h ild re n a t ris k for caries. T an d laeg eb ladet 1977, 81:225-229. 8. G ro n d ah l, H .-G .; A ndersson, B.; an d T orstens-

son, T . Caries increm ent an d progression in teenagers w h en u sin g a p re v e n tio n - ra th e r th a n re sto ra tio n o rie n te d tre a tm e n t s tra te g y . S w ed D e n t J 8:237242, 1984. 9. L uom a, H . R ecent studies o n iden tify in g caries risk subjects. Proc F in n D ent Soc 82: 47-52, 1986. 10. H eloe, L.A ., a n d H a ugejorden, O. “ T h e rise a n d fa ll” o f d e n ta l caries: som e g lo b a l aspects of d e ntal caries epidem iology. C o m m u n ity D ent O ral E pidem iol 9:294-299,1981. 11. S heiham , A. D ental caries in underdeveloped countries. In G uggenheim , B., ed. C ariolo gy today. Basel, Karger, 1984, p p 33-39. 12. K önig, K.G. Fluorides in preventive dentistry. In t D ent J 30:364-368, 1980. 13. Fejerskov, O .; T h y lstru p , A.; a n d Jo o st Larsen, M. R a tio n a l use of flu o rid es in caries p rev en tio n . Acta O d ontol Scand 39:241-249, 1981. 14. H au g ejo rd en , O ., a n d H eloe, L.A. F luorides for everyone: a review of school-based o r com m u n ity program s. C om m unity D ent O ral E pidem iol 9:159169, 1981. 15. G la ss, R .L . D e c lin in g p re v a le n ce o f d e n ta l caries. J D ent Res 61(Special Issue):1304-1383, 1982. 16. A llen, C.D.; Ashley, F.P.; a n d N aylor, M .N . Caries experience in 11-year-old school girls betw een 1962 a n d 1981. Br D ent J 154:167-170, 1983. 17. M arth aler, T .M . E x p la n a tio n s fo r c h a n g in g p a tte r n s o f d is e a s e in th e w e s te rn w o rld . In G uggenheim , B., ed. C ariology today. Basel, Karger, 1984, p p 13-23. 18. Klock, B., a n d Krasse, B. S m uta n s, lactobacilli a n d d e n ta l c a rie s in S w e d is h c h ild r e n in 1984 com pared to 1973. Caries Res 20:171, 1986. 19. B ow en, W .H . Im p a c t o n research. In G u g ­ g e n h e im , B., ed. C a rio lo g y today. B asel, K arger, 1984, p p 49-55. 20. G u stafso n , B .E ., a n d o th e rs. T h e V ip e h o lm d e n ta l c aries stu d y . T h e effect o f d iffe re n t levels o f c a r b o h y d ra te in ta k e o n c a rie s a c tiv ity in 436 in d iv id u a ls observed for five years. A cta O d o n to l Scand 11:232-264, 1953. 21. M cD onald, S.P.; Cow ell, C .R .; an d S heiham , A. M e th o d s of p r e v e n tin g d e n ta l c a rie s u sed by dentists for th eir ow n children. Br D ent J 151:118121, 1981. 22. Is m a il, A .I.; B u rt, B .A .; a n d E k lu n d , S.A . C ario g e n icity of soft d rin k s in the U n ite d States. JAD A 109(2):241-245, 1984. 23. M akinen, K.K., a n d S cheinin, A. X ylitol an d d e ntal caries. A nn Rev N u tr 2:133-150, 1982. 24. L oesche, W .J. T h e effect of s u g a r a lc o h o ls o n p la q u e and saliva level of Streptococcus m utans. Swed D ent J 8:125-135, 1984. 25. Scheinin, A., a n d M akinen, K.K. T u r k u sugar s tu d ie s. A cta O d o n to l S c a n d 3 3 (S u p p l 70):I-348, 1975. 26. G a liu llin , A .N . E v a lu a tio n o f th e c a rie sp re v e n tiv e a c tio n o f x y lito l. K azan M ed J 67:1618, 1981. 27. K a n d e lm a n , D .; B ar, A .; a n d H e fti, A. C o lla b o ra tiv e W H O x y lito l field stu d y in F ren ch Polynesia. Baseline prevalence a n d 32-m onth caries increm ent. Caries Res 22:55-62, 1988. 28. Scheinin, A., an d others. C ollaborative W H O xylitol field studies in H un g ary . T h ree year caries activity in in stitu tio n a liz e d children. Acta O d o n to l Scand 43:327-347, 1985. 29. K a n d e lm a n , D ., a n d G a g n o n , G . C lin ic a l results after 12 m o n th s from a study of the incidence a n d p ro g r e s s io n o f d e n ta l c a rie s in r e la tio n to c o n s u m p tio n o f c h e w in g -g u m c o n ta in in g x y lito l in school preventive program s. J D ent Res 66:14071411, 1987. 30. K ö n ig , K .G . I m p a c t o f d e c r e a s in g c a rie s prevalence: im plicatio n s for d e ntal research. J D ent Res 61 (Special Issue):1378-1383, 1982.

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31. L u o m a, A .-R., a n d R o n n b erg , K. A ten-year f o llo w -u p o f th e carie s p re v a le n ce a n d in cid en ce in c h ild re n o f the tow n o f Espoo. Caries Res 20:160, 1986. 32. C u lb e r t, S .J ., a n d o th e rs . O ra l x y lito l in A m erican adults. N u tr Res 6:913-922, 1986. 33. F e d e ra tio n D e n ta ire In te rn a tio n a le a n d the W orld H e a lth O rg a n iz atio n (R e p o rt o f a W o rk in g G ro u p : R enson, C.E., an d others). C h an g in g patterns o f o ra l h e a lth a n d im p lic a tio n s fo r o ra l h e a lth m anpow er. In t D ent J 35:235-251, 1985. 34. S cheinin, A. Field studies o n su g ar substitutes. In t D ent J 35:195-200, 1985. 35. Barm es, D., an d others. Field trials o f preventive re g im e n s in T h a ila n d a n d F ren c h P o ly n e sia . In t D ent J 35:66-72, 1985. 36. W orld H e alth O rg an izatio n . A guide to oral h e a l th e p id e m io lo g ic a l in v e s tig a tio n s . G e n ev a , Sw itzerland, 1979. 37. S h a w , L ., a n d M u rra y , J .J . In te r-e x a m in e r a n d in tra -e x a m in e r re p ro d u c ib ility in clin ical an d ra d io g ra p h ic diagnosis. I n t D en t J 25:280-288, 1975. 38. Heifetz, S.B., an d others. E x am in er consistency a n d g ro u p b a la n ce a t b ase lin e o f a caries clin ic al

tria l. C o m m u n ity D en t O ra l E p id e m io l 13:82-85, 1985. 39. R ich ard son, A.S., and others. A n ticariogenic effects of dicalcium dihydrate chew ing gum s: results after tw o years. J C an D ent Assoc 38:213-218, 1972. 40. R ichardson, A.S., and C astaldi, C.R . C urrent s ta tu s o f c h e w in g g u m in p re v e n tiv e d e n tistry . J C an D ent Assoc 31:713, 1965. 41. G lass, R .L . Effects on dental caries incidence o f fre q u e n t in g e stio n o f sm a ll a m o u n ts o f s u g a r a n d sta n n o u s ED T A in chew in g g u m . C aries Res 15:256-262, 1981. 42. Glass, R .L. A two-year clinical trial of sorbitol c h e w in g g u m . Caries Res 17:365-368, 1983. 43. Banoczy, J., a n d others. C ollaborative W H O x y lito l field studies in H ungary. G eneral background a n d c o n tro l o f the dietary regim en. Acta O d o n to l Scand 43:349-357, 1985. 44. H orow itz, H .S., a n d others. (C om m ission on c la s s ific a tio n a n d s ta tis tic s fo r o ra l c o n d itio n s ): P rin cip al req u irem ents for controlled clinical trials of caries preventive agents and procedures. Int Dent J 23:506-516, 1973. 45. Stam m , J.W . T ypes of clinical caries studies:

ep idem iological surveys, random ized c linical trials, a n d dem o n stratio n program s. J D ent Res 63(Special Issue):701-707, 1984. 46. Glass, R .L .; A lm an, J.E .; an d Fleisch, S. T h e m e a su re m e n t of caries in c re m e n ts by c o u n ts a n d rates. IA D R P rogram a n d A bstracts of papers, abstract no. 633, 1971. 47. Backer D irks, O. L o n g itu d in a l d e ntal caries s tu d y in c h ild r e n 9-15 y e ars o f a g e. A rc h O ra l B iol(Special Suppl)6:94-108, 1986. 48. C a rlo s, J .P ., a n d G itte ls o h n , A .M . L o n g i­ tu d in a l s tu d ie s o f th e n a tu r a l h is to ry o f c a rie s. A life-table study of caries incidence in the p e rm anent teeth. Arch O ral Biol 10:739-750, 1965. 49. N ordblad, A., and Larm as, M. A cross-sectional stu d y of carie s p re v a le n ce in F in n is h c h ild re n 617 years of age. Proc F inn Soc 76:245-252, 1980. 50. K o le h m a in e n , L. D e n tal caries on d ifferen t to oth surfaces a m o n g 13-15 year old children. Proc F in n D ent Soc 79:107-114, 1983. 51. K leem ola-K ujala, E., a n d R asanen, L. R ela­ tio n s h ip of o ra l h y g ien e a n d s u g a r c o n s u m p tio n to risk of caries in children. C om m unity D ent O ral Epidem iol 10:224-233, 1982.

Self-Assessment Questions 1. W hat are the m echanism s of action of flu o rid e (s ) a n d x y lito l in caries prevention? 2 . O nce the in c id en ce of caries has been b ro u g h t dow n th ro u g h the use of xylitol, it does n o t show any increase a t la te r sta g es; th e c a rie s -re d u c in g effect rather seems to strengthen. W hat im p licatio n s m ig h t such an effect have o n preventive dentistry? 3. Based o n th e m e ta b o lism of c a r­ bohydrates in hum ans, w hich of the fo llo w in g have n o rm a l, p ree x istin g m e ta b o lic p a th w a y s in th e h u m a n body:

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(a) fructose (b) m an n ito l (c) sorbitol (d) xylitol (e) all of the above 4 . Sugar (sucrose) substitutes com prise a variety of n u tritive an d n o n n u tritiv e sw eeteners. W h ich of th e fo llo w in g p ro v id e v irtu a lly n o c a lo rie s w h en ingested by hum ans? (a) m an n ito l (b) xylitol (c) aspartam e (d) N utrasw eet (e) sorbitol

5. T here are several products on the m arket th at are claim ed to be sugarfree. M any of th e m are sw ee te n ed w ith so rb ito l a n d they m ay also c o n ta in m a n n ito l, x y lito l, fru c to se , h ig h fructose corn syrup, glucose, glucose sy ru p s, L y casin , a sp a rta m e , or sac­ charin. W hich of these sweeteners are n o t carb o h y d rates? W h ich o ccu r in nature?

A nsw ers are fo u n d in th e P eo p le & M eetings section.