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Inhibition of the progress of root dentine caries in vitro by fluoride-releasing resin
J. Dent.
188
International Section Assistant
1993;21:188-189
Abstracts
Editor: W. R. E. Laird Section
Editor: Dr A. D. Walmsley
Inhibition of secondary caries by laminating restoration method with glass ionomer cement and composite resin. Torii Y., Kato R., lmazato S. et a/. (1990) Jap. J. Conserv. Dent. 33, 994-l 000. The purpose of this study was to investigate the inhibition of marginal leakage and artificial secondary caries by a laminating restoration method with glass ionomer cement and resin composite. Class V cavities were prepared at the cement-enamel junction on the buccal and palatal surfaces of extracted human upper premolars. Glass ionomer cement was applied onto the dentine wall prior to light-cured composite resin restoration. Microleakage around restorations was estimated using a dye penetration test. Artificial secondary caries was formed by immersion of the teeth in acidified gelatin (pH 4.5) for 4 weeks. The depth of the lesion along the cavity wall was measured by microradiography. Glass ionomer cement restoration and resin composite restorations with bulk and two-layer incremental filling methods were also estimated. The main findings were as follows: 1. Without regard to incrementation, a resin composite presented poor sealing and severe secondary caries at the gingival margin. 2. Glass ionomer cement prevented artificial secondary caries around restorations effectively, although it presented poor sealing at the cement-enamel interface. 3. Laminated restoration with glass ionomer cement and resin composite presented the best marginal sealing and prevented artificial secondary caries effectively. The results indicated that laminated restoration with glass ionomer and resin composite has an inhibitory effect on secondary caries. (24 references) H. Hisamitsu
Inhibition of the progress of root dentine caries in vitro by fluoride-releasing resin. Torii Y., Kato R., Ui T. et a/. (1990) Jap. J. Conserv. Dent. 33,1143-1150. The purpose of this study was to investigate the inhibitory effect of a newly synthesized fluoride-releasing resin on the production and the progress of root dentine carious lesion. The resin contains methacryloyl fluoridemethylmethacrylate copolymer which is able to release fluoride ion through a hydrolytic reaction (F-resin). Dentine blocks were cut from the roots of extracted bovine teeth. The specimens were stored in deionized water for 7 days after application of the resin onto sound @ 1993 Butterworth-Heinemann 0300-5712/93/030188-02
Ltd.
dentine surfaces and predecalcified dentine surfaces induced by immersion in an acetate buffer solution, pH 4.0, for 12 h. Then the resin was removed mechanically and the specimen was again immersed in an acetate buffer solution (pH 4.0) for 40 h. The inhibitory effect of F-resin on the decalcification of dentine was estimated by microhardness testing, microradiography and X-ray microanalysis. C-resin without fluoride-releasing copolymer was also estimated. The following results were obtained: 1. Microradiographic observation showed that the application of F-resin onto a sound root dentine reduced the depth of lesion as compared with that of C-resin. Microhardness-testing showed that the decalcified dentine in F-resin group was harder than those in both Cresin and no-resin group. 2. As for the effect on a predecalcified dentine, microradiographic observation showed that the depth of lesions in both F-resin and C-resin groups was significantly shallower than that in no-resin group and they were almost comparable between F-resin and Cresin groups. Microhardness testing showed that the lesion in F-resin group was harder than that in C-resin group. X-ray microanalysis showed an uptake of fluoride and an increased mineral density in the lesion of F-resin group. The results suggested that the application of fluoridereleasing resin inhibits the production and the progress of caries on an exposed root surface. (17 references) H. Hisamitsu
Studies on physical properties of bleached tooth. 1. Microstructural changes by bleaching agent. Toko T., Hisamitsu H., Wakumoto S. et a/. (1990) Jap. J. Consefv. Dent. 33, 1 102-l 1 13. A sectioned tooth surface was treated with a 31% hydrogen peroxide solution at 37°C for 2 h or 1 week, and the microstructural change of the surface with or without treatment was examined under scanning electron microscopy. The results were as follows: 1. Tubular structures (inner wall) in the dentinal tubule disappeared, and non-fibrous organic components of peritubular dentine were also removed by immersing in a 31 % hydrogen peroxide solution. 2. A demineralizing effect (exposed in 2.5% EDTA for 30 min) was conspicuously observed in sectioned dentine and enamel surfaces. This effect was accelerated by removing the organic substances in tooth components.
188
International Section Assistant
1993;21:188-189
Abstracts
Editor: W. R. E. Laird Section
Editor: Dr A. D. Walmsley
Inhibition of secondary caries by laminating restoration method with glass ionomer cement and composite resin. Torii Y., Kato R., lmazato S. et a/. (1990) Jap. J. Conserv. Dent. 33, 994-l 000. The purpose of this study was to investigate the inhibition of marginal leakage and artificial secondary caries by a laminating restoration method with glass ionomer cement and resin composite. Class V cavities were prepared at the cement-enamel junction on the buccal and palatal surfaces of extracted human upper premolars. Glass ionomer cement was applied onto the dentine wall prior to light-cured composite resin restoration. Microleakage around restorations was estimated using a dye penetration test. Artificial secondary caries was formed by immersion of the teeth in acidified gelatin (pH 4.5) for 4 weeks. The depth of the lesion along the cavity wall was measured by microradiography. Glass ionomer cement restoration and resin composite restorations with bulk and two-layer incremental filling methods were also estimated. The main findings were as follows: 1. Without regard to incrementation, a resin composite presented poor sealing and severe secondary caries at the gingival margin. 2. Glass ionomer cement prevented artificial secondary caries around restorations effectively, although it presented poor sealing at the cement-enamel interface. 3. Laminated restoration with glass ionomer cement and resin composite presented the best marginal sealing and prevented artificial secondary caries effectively. The results indicated that laminated restoration with glass ionomer and resin composite has an inhibitory effect on secondary caries. (24 references) H. Hisamitsu
Inhibition of the progress of root dentine caries in vitro by fluoride-releasing resin. Torii Y., Kato R., Ui T. et a/. (1990) Jap. J. Conserv. Dent. 33,1143-1150. The purpose of this study was to investigate the inhibitory effect of a newly synthesized fluoride-releasing resin on the production and the progress of root dentine carious lesion. The resin contains methacryloyl fluoridemethylmethacrylate copolymer which is able to release fluoride ion through a hydrolytic reaction (F-resin). Dentine blocks were cut from the roots of extracted bovine teeth. The specimens were stored in deionized water for 7 days after application of the resin onto sound @ 1993 Butterworth-Heinemann 0300-5712/93/030188-02
Ltd.
dentine surfaces and predecalcified dentine surfaces induced by immersion in an acetate buffer solution, pH 4.0, for 12 h. Then the resin was removed mechanically and the specimen was again immersed in an acetate buffer solution (pH 4.0) for 40 h. The inhibitory effect of F-resin on the decalcification of dentine was estimated by microhardness testing, microradiography and X-ray microanalysis. C-resin without fluoride-releasing copolymer was also estimated. The following results were obtained: 1. Microradiographic observation showed that the application of F-resin onto a sound root dentine reduced the depth of lesion as compared with that of C-resin. Microhardness-testing showed that the decalcified dentine in F-resin group was harder than those in both Cresin and no-resin group. 2. As for the effect on a predecalcified dentine, microradiographic observation showed that the depth of lesions in both F-resin and C-resin groups was significantly shallower than that in no-resin group and they were almost comparable between F-resin and Cresin groups. Microhardness testing showed that the lesion in F-resin group was harder than that in C-resin group. X-ray microanalysis showed an uptake of fluoride and an increased mineral density in the lesion of F-resin group. The results suggested that the application of fluoridereleasing resin inhibits the production and the progress of caries on an exposed root surface. (17 references) H. Hisamitsu
Studies on physical properties of bleached tooth. 1. Microstructural changes by bleaching agent. Toko T., Hisamitsu H., Wakumoto S. et a/. (1990) Jap. J. Consefv. Dent. 33, 1 102-l 1 13. A sectioned tooth surface was treated with a 31% hydrogen peroxide solution at 37°C for 2 h or 1 week, and the microstructural change of the surface with or without treatment was examined under scanning electron microscopy. The results were as follows: 1. Tubular structures (inner wall) in the dentinal tubule disappeared, and non-fibrous organic components of peritubular dentine were also removed by immersing in a 31 % hydrogen peroxide solution. 2. A demineralizing effect (exposed in 2.5% EDTA for 30 min) was conspicuously observed in sectioned dentine and enamel surfaces. This effect was accelerated by removing the organic substances in tooth components.