Caries Res. 12: 43-51 (1978)
The Effect of Differing Concentrations of SnF 2 on Demineralized Enamel D. J. Purdell-Lewis, J. A rends and A. Groeneveld Caries Research Unit, Organisation for Health Research TNO, Laboratory for Microbiology, University of Utrecht, Utrecht, and Laboratory for Materia Technica, University of Groningen, Groningen
Key Words. Demineralization • Enamel • Fluoride, stannous • Remineralization • White spot lesions
It has been demonstrated in clinical trials that a single annual application of an 8°/o or 10°/o stannous fluoride (SnF.,) solu tion can have a caries-preventative effect, even when applied to subjects living in a fluoridated area [Muhler, 1960a, b; Szwejda, 1972J. These concentrated solutions are
now being used less frequently because of their astringent and disagreeable taste and the side effects of gingival irritation and tooth pigmentation [Hyde and Muhler, 1963; O’Carrol and Muhler, 1963], More frequent applications of a less concentrated solution (4°/o) have also been shown to be
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 3/7/2018 3:19:41 AM
Abstract. The effect of different concentrations of stannous fluoride (SnF,) on de mineralized enamel was studied, on cross-sections, using microhardness and densitometric measurements. SnF2 solutions, ranging in concentration from 0.5 to 8%>, were applied to artificially demineralized enamel surfaces. It was found that the hardness increase in the surface layer was similar in all groups but that the radiodensity increased significantly with increasing concentration. It is suggested that these results are due to the maximum for mation of fluorapatite from the available brushite, thus improving the crystalline structure and giving equal hardness in all groups, whilst the increase in radiodensity demonstrates the incorporation of stannous ions resulting in an increase in mineralization. In the subsurface lesion there was an increase in hardness with increasing concentration. This trend was also seen in the microradiographic results but to a much greater degree. This more demineralized area requires a greater SnF2 influx for the formation of stannous compounds which appear primarily to have a space-filling and mineralizing function. It can be concluded that: (a) maximum surface rehardening occurred after the application of an 0.5% SnF., solution; (b) maximum increase in hardness and radiodensity in both the surface layer and subsurface lesion occurred after the application of an 8%> SnF2 solution; (c) hardness increases are not directly correlated to the increase in radiodensity.
effective in both fluoridated and non-fluoridated areas [McDonald and Mahler, 1957; Houwink et al., 1974]. The temperature of the fluoride solution used in a topical application plays a very important role in determining the rate of the reaction. It has been shown, for example, that a 12 C increase from room tempera ture (23 ± 2 C) to 35 C doubles the fluo ride uptake in enamel [Mellberg and Loertscher, 1972], The reaction between SnF2 and dicalcium phosphate dihydrate (brushite, DCPD). one of the breakdown products of the demineralization process [Moreno and Zahradnik, 1974], is also tem perature-dependent. A 13 °C increase from 37 to 50 C more than doubles the rate of fluorapatite formation [Purdell-Lewls et al., 1977a], Very little work has been done on the ef fect of fluorides on demineralized enamel, although it has been shown, in vivo, that these areas tend to have a higher F- concen tration than the surrounding sound enamel [Weatherell et al., 1977]. Previous reports from this laboratory have shown that the application of either a 4% or a 10°/o SnF, solution at 50 C on artificially demineral ized enamel surfaces has a rehardening ef fect, both in the surface layer and the sub surface lesion. This treatment also con ferred a significant degree of protection against further acid attack [Purdell-Lewis et al., 1976, 1977b], The purpose of this experiment was to investigate whether weaker concentrations of SnF,, which have fewer undesirable side effects, could be used successfully, particu larly if applied at a higher temperature. The SnF,-treatcd artificially demineralized hu man enamel lesions were examined in cross-section using microhardness and mi
Purdell-Lewis/Arends/Groeneveld
croradiographic techniques to ascertain the effects in both the surface layer and the sub surface lesion. Since it must be accepted that to obtain optimal results from topical fluorides they should not be applied at sto rage or room temperature, then logically the highest possible temperature should be used. This work was therefore completed at 50 °C since this is considered to be well within acceptable temperature limits at which trays with topical application fluid in warmed plastic inserts can be used in the mouth.
Materials and Methods 10 sound premolars, extracted for orthodontic reasons, were used in this study. They were lightly cleaned with pumice and covered with blue wax with the exception of a central window on the buccal surface. Artificial white spot lesions were formed by demineralizing the exposed windows at pH 4.0 for 2
The Effect of Differing Concentrations of SnF 2 on Demineralized Enamel D. J. Purdell-Lewis, J. A rends and A. Groeneveld Caries Research Unit, Organisation for Health Research TNO, Laboratory for Microbiology, University of Utrecht, Utrecht, and Laboratory for Materia Technica, University of Groningen, Groningen
Key Words. Demineralization • Enamel • Fluoride, stannous • Remineralization • White spot lesions
It has been demonstrated in clinical trials that a single annual application of an 8°/o or 10°/o stannous fluoride (SnF.,) solu tion can have a caries-preventative effect, even when applied to subjects living in a fluoridated area [Muhler, 1960a, b; Szwejda, 1972J. These concentrated solutions are
now being used less frequently because of their astringent and disagreeable taste and the side effects of gingival irritation and tooth pigmentation [Hyde and Muhler, 1963; O’Carrol and Muhler, 1963], More frequent applications of a less concentrated solution (4°/o) have also been shown to be
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 3/7/2018 3:19:41 AM
Abstract. The effect of different concentrations of stannous fluoride (SnF,) on de mineralized enamel was studied, on cross-sections, using microhardness and densitometric measurements. SnF2 solutions, ranging in concentration from 0.5 to 8%>, were applied to artificially demineralized enamel surfaces. It was found that the hardness increase in the surface layer was similar in all groups but that the radiodensity increased significantly with increasing concentration. It is suggested that these results are due to the maximum for mation of fluorapatite from the available brushite, thus improving the crystalline structure and giving equal hardness in all groups, whilst the increase in radiodensity demonstrates the incorporation of stannous ions resulting in an increase in mineralization. In the subsurface lesion there was an increase in hardness with increasing concentration. This trend was also seen in the microradiographic results but to a much greater degree. This more demineralized area requires a greater SnF2 influx for the formation of stannous compounds which appear primarily to have a space-filling and mineralizing function. It can be concluded that: (a) maximum surface rehardening occurred after the application of an 0.5% SnF., solution; (b) maximum increase in hardness and radiodensity in both the surface layer and subsurface lesion occurred after the application of an 8%> SnF2 solution; (c) hardness increases are not directly correlated to the increase in radiodensity.
effective in both fluoridated and non-fluoridated areas [McDonald and Mahler, 1957; Houwink et al., 1974]. The temperature of the fluoride solution used in a topical application plays a very important role in determining the rate of the reaction. It has been shown, for example, that a 12 C increase from room tempera ture (23 ± 2 C) to 35 C doubles the fluo ride uptake in enamel [Mellberg and Loertscher, 1972], The reaction between SnF2 and dicalcium phosphate dihydrate (brushite, DCPD). one of the breakdown products of the demineralization process [Moreno and Zahradnik, 1974], is also tem perature-dependent. A 13 °C increase from 37 to 50 C more than doubles the rate of fluorapatite formation [Purdell-Lewls et al., 1977a], Very little work has been done on the ef fect of fluorides on demineralized enamel, although it has been shown, in vivo, that these areas tend to have a higher F- concen tration than the surrounding sound enamel [Weatherell et al., 1977]. Previous reports from this laboratory have shown that the application of either a 4% or a 10°/o SnF, solution at 50 C on artificially demineral ized enamel surfaces has a rehardening ef fect, both in the surface layer and the sub surface lesion. This treatment also con ferred a significant degree of protection against further acid attack [Purdell-Lewis et al., 1976, 1977b], The purpose of this experiment was to investigate whether weaker concentrations of SnF,, which have fewer undesirable side effects, could be used successfully, particu larly if applied at a higher temperature. The SnF,-treatcd artificially demineralized hu man enamel lesions were examined in cross-section using microhardness and mi
Purdell-Lewis/Arends/Groeneveld
croradiographic techniques to ascertain the effects in both the surface layer and the sub surface lesion. Since it must be accepted that to obtain optimal results from topical fluorides they should not be applied at sto rage or room temperature, then logically the highest possible temperature should be used. This work was therefore completed at 50 °C since this is considered to be well within acceptable temperature limits at which trays with topical application fluid in warmed plastic inserts can be used in the mouth.
Materials and Methods 10 sound premolars, extracted for orthodontic reasons, were used in this study. They were lightly cleaned with pumice and covered with blue wax with the exception of a central window on the buccal surface. Artificial white spot lesions were formed by demineralizing the exposed windows at pH 4.0 for 2
