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From : The Uepartment of an atom^, Ynirersity o f Gotehorg, Sweden.
REVERSALS IN CARIES DIAGNOSIS
INTKOUYCTIOS
In periodically repeated caries registrations there will always appear a certain amount of reversals i.e. cavities detected at the first but not a t the following registrations. Clinical tests with various methods of local application of fluorides suggest a 110- sitive correlation between the caries reduction obtained and the number of reversals registered (Radike & Jlrihler, 1931; Howel l , Gish, Sriiiky & Mtrhler, 1955 ; Snnducill-Hagland, 1933 ; Jlrrhlcr, 1958, 19.59 and 1960; L4bdul-Ghclffnr & Muhler, 1959; Pef f l ey & Mrrhler, 1960; Hadike 1960; Goaz, JIcEluminc, Biswell & White , 1963). This correlation has been ascribed to a remineralisation of carious sites brought about by the fluorides applied. The pre- sent paper reports further exploration into the mechanism of reversals tvhereby use was made of data-) from the fluoride study in Giiteborg (Torell & Ericsson, 1965). For the convenience o f the readers the characteristics of this survey will be recapitulated here.
l 'he Giiteborg study included six experimental and three control groups. A t the stai-t each group contained about 200 randomly assigned 12 years old children. The experimental t ime m a s two years. l'he caries si tuation was reg-
") 'I'he da ta were programmed for and processed by an IBJI 1401 electronic computing machine. The expenses were defrayed by a grant f rom 'Patentme- tielsfonden fiir otiontologisk profylaxforskning'
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192 PER TORELL
istered in two separate ways, clinically and radiographically. The registra- tions were made at three occasions, a t the beginning of the study, after a year and at the end. The children were given full dental care shortly before the first registration and immediately after the second.
No significant differences in preexperimental caries experience were found between the groups. Figure 1 shows the number of new DMF-surfaces de- tected clinically in the nine groups during the two experimental years. The radiographical data corroborated the results of the clinical evaluation.
66teborg study
Mean numbers o f new DMF-surfaces recorded c l i n i c a l l y .
1
Fig. 1. Group denotions : NaF-paint = topical application of 2 % NaF solution according to Knutson. SnF,-paint = single topical application of 10 % SnF, solution. NaF-wash 1/1 = daily mouthwash with 0.05 % NaF solution. NaF-wash 1/14 = mouthwash with 0.2 % NaF solution every fortnight. SnF,-Ca2P20,-dfr. = dentifrice containing stannous fluoride and calcium
Ca2P207-dfr. = control for SnF2-CaP207-dfr. NaF-NaHC03-dfr. = dentifrice containing sodium fluoride and sodium bi-
NaHC03-dfr. = control for NaF-NaHC0,-dfr. Control = main control group. Asterisks denote significance of difference between compared groups.
pyrophosphate.
carbonate.
A great deal of the reversals noted in a clinical study emanate from observation and recording errors, wavering interpretation of the criteria used for the diagnosis of dental caries, environ- mental changes caused by tooth eruption etc. Hence only a part of the reversals noted can possibly have been effected by remine-
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n E r E n s A L s I N CARIES DIAGNOSIS 193
ralisation. When the significance of reversals is discussed it is necessary to keep in mind that reversals can be caused by two entirely different phenomenons, registration failures and remine- ralisation.
Clinical reversals in the Goteborg study
M.\TERIAL AND JIETHOI)
The numbers of clinical reversals in the nine groups were calculated from the data of the first and the second registrations. The data of the third registration were not made use of because the participating children had been given a full dental treatment immediately after the second registration. As full dental care had been given to the participants shortly before the start of the study, almost all carious lesions detected at the first registration must have been small. This ought to have presented an expedient basis for the establishment o f reversals a t the second registration.
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Fig. 2. Thc rcversals noted at the second registration expressed as percentages of the c:ivities recorded init ial ly .
1 3 ~ Act11 f l t lont . sctrnd. 1-01, 23.
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194 P E R TonELL
Table I. The occurrence of reversals at the second registration.
Initial cavities
Reversals a t the second reyistration Number Percentage of initial cavities
1 NaF-paint. 135 27 20.0 % 2 SnF2-paint. 157 34 21.7 % 3 NaF-wash. 1/1 86 21 24.4 % 4 NaF-wash. 1/14 175 54 30.9 % 5 SnF2-Ca2P20,-dfr. 166 42 25.3 % 6 Ca2P20,-dfr. 128 24 18.7 % 7 NaF-NaHC0,-dfr. 136 35 25.7 % 8 NaHC03-dt'r. 127 34 26.8 % 9 Main control 156 37 23.7 %
Significant differences
NaF-wash. 1/14 vs Ca2P20,-dfr. = 12.2 % * 4.9 NAF-wash. 1/14 vs NaF-paint. = 10.9 % * 4.9
RESULTS
The number of reversals are given in Table I and in figure 2. No significant differences were found between the reversal figures of the main group and those of the other groups. Statistical diffe- rences were calculated for the group given fortnightly mouth- washes with a 0.2 % sodium fluoride solution uersus the group given four topical applications with a 2 % sodium fluoride solu- tion as well as uersus the group given calcium pyrophosphate dentifrice.
DISCUSSION
A collation of the data shown in Table I and Figure 2 gave no evidence of a correlation between reversals and caries reduc- tion. This finding was not in agreement with the reversal studies cited above. An explanation of the divergency had therefore to be looked for.
A compilation of the relevant papers showed that the caries activity of the Gotehorg control groups was decidedly higher than the caries activity of the control groups employed in the contradictory reversal studies. This may provide the key to the desired explanation. According to a number of reports, reviewed by Torell (1962), it is obvious that demineralizing as well as mineralizing forces are involved in the development and progress of dental caries. The caries activity is thus determined by the balance between these two types of forces. The fluoride treat-
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I{liYEI{ShLS IN CAIIIES DI.AGNOSIS 19,;
nient given to the highly caries active Giiteborg groups may not hare been able to counteract the demineralizing forces sufficiently to establish conditions necessary for a repairing o f clinically diagnosed carious lesions. Or, the observation time, one year, may not have been long enough for the arresting of a carious lesion and the subseqiient rehardening of its surface. The last assumption is supported hy a previous non-fluoride Giiteborg study, in which no arrested caries areas with shiny, unbroken surface had been found on teeth, m-hicli had been erupted less than f i v years Torell , 1955).
The insignificant rerersal data obtained in the present study do not preclude that the fluoride treatment ma!- have had a delaying action on the growth of diagnosed cavities. Such an effect was reported by IZergriinn ( 1953) and Suntlurrll-Hnglrind (195-5 j frorn topical applications with 2 76 sodium fluoride S O ~ L I -
tions. For a further discussion of the mechanism of reversals it was found valuable to unravel if this delaying phenomenon 1i:id been in action in the Giitehorg study too.
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Fig. 3. 'The percentage of the carious les ions of t h e second ~.aciiog':lphical regis t ra t ion which Iiat l not been detected cl inical ly al t h e end o f tlica study. A
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P E R TORELL 196
Radiographical vs clinical findings
To a large extent proximal cavities are detected earlier by radio- graphical than by clinical examination (Backer Dirks, uan Ame- rongen & Winkler 1951). This phenomenon was thought to be related to caries activity; the lower the caries activity the longer the time between the radiographical and the clinical detection of carious lesions.
MATERIAL AND METHOD
Each caries notation made on the x-ray charts at the second registration was related to the clinical notation for the same tooth surface made at the third registration. By tabulating the findings it was possible to determine the number of radiolucencies of the second registration which had not been diagnosed cli- nically at the third registration.
RESULTS
Table I1 presents the relation between the radiographical and the clinical notations in the nine different groups. It gives also a
% I
Fig. 4. The percentage of the enamel lesions of the first radiographical re- gistration which were classified as enamel lesions a t the second radio- graphical registration. A
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REVE:RS.kLS I N CARIES DIAGNOSIS 1'37
statistical evaluation based on differences between the groups as to the percentage numbers of radiolucencies not detected cli- nically a t the third registration.
The statistical evaluation revealed : ( 1) significantly inore radiolucencies were detected clinically in the group given the stannous fluoride than in any of the other groups, (2 ) signi- ficantly less radiolucencies were detected in the daily mouth- washing group than in any other group with the exception of the sodium fluoride dentifrice group.
DISCUSSION
The results indicate that powerful fluoride treatments can delay the growth of carious lesions in a district with high caries activity. Apparently it is necessary to have a higher initial re- mineralisation potential than that of non-fluoride Giiteborg, if fluoride applications shall effect a rapid healing of diagnosed
Table 11. S~i ir iber of curious les ions of the second radiographical regis trat ion which h d t i o i detected rliniccilly a t the end of the s t u d y .
~ _ _ _ _ _ _ _ _ _________ ~~~~~~ -
Not detected clinircilly X-ray cavi t ies .\'umber Perceiitcige of X-ray cavi t ies
1 NaF-paint. 230 6 ,> 28.3 '%
3 NaF-wasii. 1/1 21T 8 i 10.1 '7,
4 NaF-wash. 1/14 305 !I 0 29.5 %
2 SnFe-paint. 240 72 30.0 %
5 SnF2-Ca,I',0,-dfr. 302 59 19.3 % 6 CaeP*Oi-dfr. 3.55 92 25.9 9; 7 NnF-SaHC03-df'r. 230 78 33.9 '% 8 NnI-IC03-dfr. 111 116 28.2 % 9 M n i n control 3 i l 119 32.1 %
~~~~ ~ ~~~ ~~~ ~~~~~~~ ~~~ ~~ ~~~~
Sign iliccin t tli f f erences
*5 vs 3 = 20.0 % * 4.0 3 V S 5 = 20.6 7c ? 4.0 5 vs 7 = 14.4 % 2 3.9 3 vs 6 = 14.2 '% i- 1.1 .3 vs 9 = 21.6 % t- 3.3 3 vs 8 = ll.!) 7G * 4.0 5 vs 2 = 10.5 % t- 3.7 3 vs 1 = 11.8 % 5 4.5 .i v s 4 z 10.0 % * 3.7 3 vs 4 = 10.6 a i- 1.2 3 vs 1 = 8.8 % t- 3.7 3 vs 2 = 10.1 % ?r 4.5 .5 vs 8 = 8.7 % k 3.2 3 vs 9 = 8.0 74 i- 4.1 5 v s 6 = 6.4 % 5 3.2
7 vs 6 :: 8.0 7; = 3.9 ~~ ~~~~ ~~~~ ~~ .. ~ ~~~ ~~~~
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198 PER TOIiELI,
carious areas and thereby significantly increase the number of clinical reversals found in short-time caries stirdies.
In the present study it was easier to diagnose caries clinically in the group given stannous fluoride dentifrice than in any other group. Without doubt this phenomenon is a consequence of the well-known discolouration of carious areas established by tin preparations. This caries disclosing mechanism must necessarily reduce the number of reversals of the error type and thus counter- balance the possible increase of reversals caused by reminera- lisation.
It was more difficult to diagnose caries clinically in the group given daily mouth-washes with 0.05 % sodium fluoride solutions than in any other group. Apparently this group aquired an in- creased tendency towards reversals during the experiment. The data of the Goteborg study thus indicate that more reversals are to be expected from non-colouring sodium fluoride preparations than from discolouring tin fluoride preparations. This is not in accordance with several of the stannous fluoride studies cited above.
It was assumed that the divergency might be derived from different criteria used to diagnose dental caries. Muhler stated in 1958 that the discolouration of carious sites brought about by tin ions signifies that the caries process has been arrested. His declaration has not been substantiated by experimental data. However, examiners sharing his opinion may be inclined to regard discoloured areas as non-carious. In Goteborg, on the other side, a number of remineralized areas might have been wrongly denoted as progressively carious owing to the presence of pigmentation. The possibility last discussed is examined in the following section.
The progress of caries, radiographically studied
The cavities detected radiographically in the Goteborg study were distributed in two groups according to whether or not the dentin had been reached by the carious process. The progress of the ”enamel cavities” recognized at the first registration was determined by an examination of the radiographs from the second registration. A table was prepared, presenting the number of
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REVERSALS IN CARIES DIAGNOSIS 199
preexperiinental enamel lesions which had not proceeded into the dentin during the first experimental year.
HESVL'I'S
l h e caries progress in the nine groups is presented in Table 111 and in Fig. 4. The highest value indicating the slowest advance of the caries process was registered in the group given daily mouth- washes with 0.05 ?< sodium fluoride solutions. The lowest values were obtained in the tmo groups using dentifrices with sodum bi- carbonate as the abrasive. Each of these two groups differed sig- nificantly from the groups given (1) daily mouth-washes with 0.03 clc sodium fluoride solutions, ( 2 ) fortnightly mouth-washes with 0.2 % sodium fluoride solutions and ( 3 ) four topical ap- plications mith 2 5; sodium fluoride solutions. The fluoride-free sodium bicarbonate dentifrice group also differed significantly or almost significantly froin the group given the single stannou\ fluoride application, the main control group and the calcium py-
Eiiamcl cavities Cavities restricted still a t the first to the enamel a t the
registration second registration Srtmber Percenttryr
~~~
1 NaF-paiut. 112 92 ti4.S % 63.6 'i; 2
3 S:lF-\v~lsIl. 1 / 1 142 97 68.8 ': 4 SaF-wash. 1 /14 180 116 l i l . 4 c; 5 SiiF,-(;~i,PBOi-tll'I-. 158 90 .) I .o c; (i Ca2P20,-dfr. 178 109 61.2 ": 7 NnF-SaIICO,-tlfl . 116 6 1 52.6 7;
- - Sn F2-p ii i 11 t . 118 I J
- -
S SaH(:Oy-dfi-. 201 104 51.7 5;. 9 hlaiii coiitrol 172 106 6 1 . 6 5
~ - .. .~ .- ..
Siyiii/ictrnt differences X vs 3 = 16.6 "/o f 5.3 7 YS 3 = 15.7 74 ? 6.0 8 vs 1 = 1 3 . 1 70 * 5.3 7 vs 1 = 12.2 7c 2 6.1 8 vs 1 = 12.7 % 2 5.0 7 vs 1 = 11.8 70 k 3.8 S vs 2 = 11.9 Yo i 5.7 7 \-s 2 = 11.0 'Z ? 6.4 s vs 9 = 9.9 Sb ? 5.1 8 v s 6 = 9.5 76 i 5.1 3 vs 5 = 11.3 7'~ k 5.6
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rophosphate dentifrice group. Besides a significant difference was found between the daily mouth-washing group and the stan- nous fluoride dentifrice group.
DISCUSSION
The rapid progress of the carious lesions in the groups given dentifrices with abrasive sodium bicarbonate particles may pos- sibly have a connection with the calcium complexing capacity of the carbonate ions (Ericsson, 1949; Hagen, 1965).
The radiographical study presented in this section does not lend support to the hypothesis that the discolouration of caries lesions established by tin fluoride preparations should signify an arrest of the caries process. On the other side it gives added evidence to the validity of the manner in which the criteria for the diagnosis of dental caries were handled in Goteborg.
The data of this paper thus indicate that the divergencies be- tween the stannous fluoride studies cited previously and the Goteborg study probably depend on the caries criteria used.
The following consequencies of the present findings may be noticed. Pigmenting preparations used in caries prophylactic studies can result in (1 ) too high caries reduction figures if caries processes located in pigmented areas are usually believed to be arrested, (2) too low caries reduction figures if pigmented sur- faces are usually regarded as progressively carious or (3) biased caries reduction figures owing to the difficulty to perform a blind test i f the carious areas of the experimental group are discoloured during the study.
The discussion made above indicates that caries reduction figures calculated in clinical studies with pigmenting preparations must be regarded as unreliable unless they are corroborated by a separate evaluation of radiographical data.
SCMMARY
The data of the Goteborg study (Torell & Ericsson, 1965) were used to examine the appearance of reversals. There was no in- dication of a relation between the number of reversals in the nine groups and the caries reduction obtained. It was found easier to recognize caries lesions clinically in the stannous fluoride denti-
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REVERSALS I N CARIES DIAGNOSIS 201
frice group than in any other group. This was ascribed to the well-known discolouring action of the tin ions. It was found more difficult to detect caries lesions in the group given daily mouth- washes with 0.05 % sodium fluoride solution than in the other groups. This was thought to indicate that the fluoride mouth- washes had established a higher remineralisation tendency in this group.
A comparison of x-ray data did not support the hypothesis that the discolouration of carious sites caused by tin fluoride prepa- rations should signify an arrestment of the carious process.
It was concluded that figures calculated in clinical studies with discolouring preparations may be regarded as unreliable un- less they are corroborated by a separate evaluation of radio- graphical data.
RESUME ANNULATIONS D A N S LE DIAGNOSTIC DE LA CARIE
Les renseignements recueillis lors de l’etude de Gijteborg (To- re11 65 Erirsson 1965) ont ktk utilises pour faire une ktude des cas d’annulations de diagnostics de carie. I1 n’a pas semble y avoir de rapport entre le nornbre d’annulations dans les neuf groupes et les reductions de la carie obtenues. I1 est apparu que le diagnostic clinique des caries ktait plus facile faire dans le groupe utilisant le dentifrice au fluorure stanneux que dans aucun des autres groupes. Ce fait est attribui. a la coloration provoquke, conime on le sait, par les ions Ctain. I1 est apparu que le diagnostic des caries btait plus difficile & faire dans le groupe effectiiant les rincages de bouche qiiotidien avec la solution de fluorure de sodium A 0,05 ’f% clue dans les autres groupes. Cela senible in- diquer clue les rinGages au fluorure de sodium auraient dCter- mink tine plus grande tendance h la rerninCralisation dans ce groupe.
La roniparaison des rksultats des examens radiographiques n’a pas confirnil. I’hypothkse suivant laquelle la coloration des caries proroc1ui.e par les produits a base de fluorure d’ktain signifierait tin arr6t d n processus de la carie.
En conclusion, on ne saurait se reposer sur les donnks oh- tenues dans les 6tudes cliniques au nioyen de produits dkter-
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202 PER TORELI,
minant un changement de couleur, A moins que ces donn6es ne soient confirmkes par 1'6tude faite indkpendamment sur les r6- sultats radiographiques.
ZUSAMMENFASSUNG
REVERSALIEN IN DER KARIESDIAGNOSE
Die Daten aus der Goteborg-Studie (Tore21 & Ericsson, 1965) wurden dazu benutzt um die Erscheinung der Reversalien zu un- tersuchen. Es ergab sich keine Abhangigkeit zwischen der Anzahl der Reversalien in der neun Gruppen und der erhaltenen Reduktion der Zahnkaries. Es war leichter kariose Lasionen festzustellen in der Gruppe, die Zinnfluorid-Zahnpaste benutzten als in j eder anderen Gruppe. Dies wurde dem wohlbekannten verfarbenden Vermogen der Zinn-Ionen zugeschrieben. Es war schwieriger ka- riose Lasionen festzustellen in der Gruppe, die tagliche Mund- spiihlungen mit 0,05 % Natriumfluoridlosung unternahmen, als in jeder anderen Gruppe. Dies wurde als ein Zeichen dafiir ge- nommen, dass die Fluorid-Mundspiihlungen eine hohere Remine- ralisations-Tendenz in dieser Gruppe errichtet hatten.
Die Rontgen-Daten der Goteborg-Studie unterstutzten nicht die Hypothese dass die von Zinnfluorid-Praparaten verursachte Ver- farbung von Kariesstellen ein Anhalten des Kariesprozesses be- deuten soll. Es wurde gefolgert, dass klinische Untersuchungen mit verfarbenden kariesverhiitenden Praparaten nicht zuverlassig sind, falls sie nicht von separaten Rontgenuntersuchungen unter- stiitzt werden.
REFERENCES
Abdizl-Ghaffar, H . & J . C . Muhler, 1959: Pretreatment of teeth with sodium fluoride prior to stannous fluoride application in children. J. dent. Res. 38: 901.
Backer Dirks, O., J . uan Anierongen h K . C . Winkler, 1951: A reproducible method for caries evaluation. J. dent. Res. 30: 346.
Rergman, G., 1953: The caries inhibiting action of sodium fluoride. Acta odont. scand. 11: suppl. 12.
Ericsson, Y., 1949 : Enamel-apatite solubility. Acta odout. scand. 8: suppl. 3. Goaz, P. W., L. P . McElwaine, H . E . Biswell h W . E . Whi te , 1963: Effect of
daily applications of sodium monofluorophosphate solution on caries rate in children J. dent. Res. 42: 965.
Hagen, A . R. , 1965 : Dental enamel in inorganic salt solutions. Universitetsfor- laget, Oslo.
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REYERSALS IN CARIES DI .KNOSIS 203
H o u i r l l , (:. I.., C . 7I‘. G i s h , R . L). S m i l e y h J . C . Muhler, 195.5 : The effect ot topically applied stannous fluoride on deutal caries experience in childrcn. .J. Amer. dent. Ass . 5 0 : 11.
Mzrhler, J . C., 1958 a : Effects of fluoride and nonfluoritie containing t in salts on tlie dental caries erpericnce in childrcu. d . dent. Res. 3 7 : 422.
Mnhler , 1. C., 1958 1) : Topical treatment of the teeth wi th stannous fluoridc. Single application technique. d. Dent. Child. 2 5 : 306.
Muhler, . I . C., 19.59: The combined anticariogenic effect of a single stannous fluoride solution and the unsupervised use of a stannous flnoritle containing dentifrice. d. dent. Res. 38: 994.
Muhler , . I . (;., 1960: Combined nnticariogenic effect o f a single stannous fluoride solution and the unsupervised use of :I stannous fluoride- containing dentifrice. 11. Results a t tlie end of two years. .J. dent. Res. 5 9 ; 953.
l’effley, ( i . E . & .I . C . Miihler, 1960: The effect of a commercial stannous fluoride dentifrice under controlled brushing habits on dental caries inciclence in children: Preliminary report. .J. dent. Iles. 39 : 871.
Hadike , .4. 77’. d., lD( i0 : A study of reversals in diagnosis of carious lesions. I n ’Caries diagnosis and experimental caries conference.’ Ed. G. E. (ir-een & P. R. \Yeinstein, Ohio State university research fouudation.
R o d i k e , .4 . TI’. h J . C . Muhler , 1954: Effect of reversals in diagnosis and interpretation of clinical caries tests. 3 . dent. Res. 33: 682.
.Siindrirtll-Hrigl*nd, Z., 1953: Sodium fluoride application to the deciduous dentition. Stockholm 1955.
T o r e l l , P . , 1935 : Acid resistaut substances in arrested caries lesions. Odont. 1’. K3: 495.
T o r ( , / / , l ’ . , 1962: Iiaricspi-ofylax genom lokal fluorterapi: Srcnsk Tand1iik.-T. .Xi: 1 3 3 .
Tore l l , I’. h 1.. Ericsson, 1965 : Two-year clinical tests wi th different methods of 1oc:il caries-preventive fluorine application in Swedish sehool- children. Acta odont. scand. 23: 287.
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