Australian Dental Journal, December, 1979

Volume 24. No. 6

395

Effects of stannous fluoride and amine fluorides on caries incidence and enamel solubility in adults

A. Obersztyn K. Kolwinski J. Trykowski

and S. Starosciak

Institute of Stomatology, Postgraduate Training Centre, Military Medical Academy, Warsaw

ABSTRACT-Three groups of men aged 19 to 22 years were examined. Group A was regarded as control, group B was treated topically with stannous fluoride solution every 6 months, group C received a gel for brushing once a week. All the subjects were re-examined after 6, 12, 18,24,30 and 36 months and DMFS scores were analysed. In the end of the trial 639 teeth from 213 participants were evaluated in vivo for enamel solubility rates by the CRT test. After three years of treatment both examinations disclosed that the gel was more effective in dental caries inhibition and reduction of the enamel solubility in acids, than stannous fluoride solution.

( Receiredfor puhlication June, 1978. Revised June, 1979)

Introduction Topical application of various fluoride compounds

was introduced simultaneously with water fluoridation. The remarkable anticaries efficacy of stannous fluoride’ and amine fluorides2, has been well documented in the last decade. There is evidence that amine fluorides are superior to the other fluoride compounds, particularly in reducing enamel solubility in acids4. To supplement

I Scola. F. P. -Self preparation stannous fluoride prophylactic technique in preventive dentistry: Report after two years. J.A.D.A.. 81: 12, 1369-1372 (Dec.) 1970.

* Marthaler, T. M.-Caries inhibition after seven years of unsupervised use of an amine fluoride dentifrice. Brit. D. J., 124: 1 1 . 510-515 (June) 1968.

’ Muhlemann. H. R.- Die kariesprophylaktische Wirkung der Aminfluoride. I . 10 Jahre Erfahrungen. Quintessenz, 18: 5 - 8 . 1967.

Gulzow. H. J.-Uber die Beeinflussung der Siurelflslichkeit der SchmelzoberFdche durch Aminfluoride. Deutsch Zahn- aerztl 2.. 21 : 2. 290- 295 (Feb.) 1966.

’ Giilzow. H. J.. Jellinghaus. M.-Kariesprophylaxe durch lokale Applikation von Fluorid als LBsung. Lack oder Gel. Deutsch Zahnaerztl 2.. 2X: 5. 592-597 (May) 1973.

previous work6 we now report the results of an investiga- tion of topical application of stannous fluoride solution and amine fluoride gel with regard to their inhibitory effect on dental caries and solubility of enamel in adults.

Materials and methods

Three hundred young men 19 to 20 years of age were selected from students of the engineering college in Warsaw, and divided into three equal groups (A, B, and C) the baseline DMFS for each group was determined.

Group A received no prophylactic treatment and served as a control. Group B received a prophylaxis every six months with paste containing 30 per cent stannous fluoride,* followed by direct topical application of a

* Alfa Inorganic Vcntrom. Bererly. M a w . U S A

Obersztyn, A., Piotrowski, Z., Kolwinski, K., Ekler, B.- Fluorek cynawy w profilaktyce prochnicy u doroslych. Czas. Stomatol., 26: I I , 1181-1187 (Nov.) 1973.

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10 per cent stannous fluoride aqueous solution. The students from the Group C brushed their teeth once a week with a gel containing both 297 and 335 amine fluorides and sodium flu0ride.t Toothbrushing had been done simultaneously by all participants of the C group,

Australian Dental Journal, December, 1979

N HCI solution. The elapsed time in seconds for colour change from yellow to violet was taken as a measure of acid resistance of the enamel covered by the filter disk. All measurements were compiled in daylight by the same two examiners and the data were analysed.

D M F S Reduction Group N , * Mean D M F S N,' Mean D M H N , * Mean D M F S N,* Mean D M F S (percent)

Standard errors in parentheses. * Number of subjects at initial examination and at I . 2. and 3 year examinations.

t P<0.01 .

Group A Group B Group C Percentage increase - ~~ _ - ~ --- Tooth types

N Medn SE N Medn SE N Medn SE A. B A. C B, C

Upper incisor5 69 73 27 0 50 75 90 38 0 YO 69 94 85 0 74 22 5* 24 4* 4 9. Upper canine\ 69 80 76 0 51 75 105 X7 1 02 69 112 57 I 17 3 1 0' 79 3* 6 3' Lower premolar5 69 66 86 0 47 75 82 10 0 85 69 81 92 0 63 22 7' 22 4* 0 18

N =Number of teeth SE = Standard error.

* P<0.0001.

lasted five minutes. and was supervised by the dentist. Each student was treated 40 to 45 times annually. DMFS scores were recorded after 6. 12. 18, 24, 30 and 36 months and analysed statistically. The examination was made using dental mirrors, sharp explorers. com- pressed air, and transillumination. N o radiographs were taken. All examinations were made by the same examiner whose skills in the use of D M F tooth and surface indices had been carefully calibrated.

Enamel solubility rates were determined in 0.1 N HCI after 36 months of treatment using an in V ~ W J Colour Reaction Time (CRT) test adopted from G u l ~ o w . ~ The measurements were performed on right or left maxillary central incisors and canines (the labial surface near the incisal edge) and on the tirst right or left man- dibular premolars (the buccal cusp). A 2 mm diameter disk of Whatman No. 540 filter paper previously im- mersed in 0.02 per cent aqueous crystal violet dye and dried was placed on the pumiced and dried enamel surface. The disk was then wetted with 1.5 ml of a 0.1

~~

t Elmer Gelee. G A B A S A R . i d Suiuerl.ind

Results and discussion

During the three years 52 participants withdrew from the experiment. The reasons for withdrawal were: leaving the college or not passing examinations, and unspecified reasons. There were no students discontented with the treatment. Differences between average pre- treatment and post-treatment DMFS scores were found to be statistically significant ( P <0.01) in Groups B and C after 36 months (Table 1). The DMFS increment was highest (10.54) in the control (Group A), lower (6.10) in the stannous fluoride group (Group B) and lowest (5.44) in the fluoride gel group (Group C). When the increment in mean DMFS in both test groups was compared. the amine fluoride gel produced somewhat greater. but not statistically significant, results in caries inhibition (48.4 per cent 11s 42.1 per cent). However. the inhibition for both Groups was significant ( P < O . O l ) when compared with the untreated control (Table I ) .

The data from the in vivo C R T test show that both fluoride compounds reduced enamel solubility signifi- cantly ( P < O . O O O I ) for all tested tooth types (Table 2). A significantly greater reduction ( P < O . O O O I ) for the

Australian Dental Journal, December, 1979 397

central incisors (29.4 per cent) and the canines (39.4 per cent) and the premolars (26.7 per cent) occurred in the amine fluoride group. Corresponding values were 23.3 per cent, 31.0 per cent and 22.7 per cent in the stannous fluoride group. The comparison of the reduction for the first lower premolars showed no difference. Vertical comparison of the table by tooth types shows that the highest mean rates were found in all instances for maxillary canines, next maxillary central incisors. and the lowest for mandibular first premolars. According to Weatherell. Robinson. and Hallsworth.’ variability 111

fluoride is due to differences in tooth composition and enamel wear concentration, The lower values for the buccal cusp of the lower first premolars could be mostly attributed to persistent wear of the enamel surface during chewing.

’ Weatherell, J. A,, Robinson, C., Hallsworth, A. S. -Changes in the fluoride concentration of the labial enamel with age. Caries Res., 6 : 4, 312-324, 1972.

It is hard to draw a comparison between the results of our study and the data of Gulzow and Jell inghau~.~ In both studies however, the amine fluoride gel gave the best results in enamel solubility reduction in adults. The greater effectiveness of amine fluoride gels indicates that it may be recommended as time-saving, and as an economic agent for caries prevention in adults.

Since the brushing with fluoride gel was supervised by the dentist it is possible that unsupervised brushing may not produce a similar result. It should be noted that the difference in reduction of mean DMFS in the two fluoride groups (B, C) was not great and the supervision by the dentist for the brushing was time consuming and therefore cannot be overlooked as an economic factor.

Institute of Stomatology, Postgraduate Training Centre of

Military Medical Academy, 128 Szaserow Street,

04349 Warsaw, Poland.