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Hydrodynamisches verhalten der Dentin-Tubulus-Flüssigkeit unter okklusasler Belastung.
58
J. Dent.
1992;
20:
No. 1
restoration/tooth interface. The radioisotope technique generally indicated a greater degree of leakage than did the ultraviolet dye technique. This should not be construed, however, to mean that the radioisotope test is necessarily more discerning than the ultraviolet dye test. For example, the radioisotope test did not detect a significant difference between the ‘No treatment’ and Copalite groups at the occlusal margin that was detected by the ultraviolet dye test. This outcome occurred, in large measure, because the differences in degrees of leakage detected by the two tests were not consistent for all groups. Future research should be directed toward attempting to determine if these inconsistencies extend to other microleakage detection tests. The possibility that testing order may affect the outcome should also be examined. In this study, the specimens were first exposed to the radioisotope and then, in a separate step, were exposed to the ultraviolet dye. This was intentionally done to prevent dye contamination of the radioisotope solution. Ideally specimens should be exposed to both media simultaneously to prevent testing order from having an effect on the outcome. Microleakage detection tests have played an important role in dental research and have enabled investigators to assess the ability of restorative materials to seal the restoration/tooth interface. The results of this study suggest, however, that individual tests do not yield equivalent results and that they should not be considered to be interchangeable.
International
References Christen A G. and Mitchell D. F. (1966) A fluorescent dye method for demonstrating leakage around dental restorations. J. Dent. Res. 45, 1485-1492. Crim G. A., Swartz M. L. and Phillips R. W. (1985) Comparison of four thermocycling techniques. J. Prosthet Dent. 53, 50-53. Going R. E. (1972) Microleakage around dental restorations: a summarizing review. J. Am. Dent Assoc. 84, 1349-1357. Granath L. (1967) Studies on microleakage with restorative materials. Part I. Introductory experiments on amalgam. J. Dent Res. 46, 1331-1336. Guzman H. J., Swartz M. L. and Phillips R. W. (1969) Marginal leakage of dental restorations subjected to thermal stress. J. Prosthet Dent. 21, 166-175. Hirsch L. and Weinreb M. M. (1958) Marginal fit of direct acrylic restorations. J. Am. Dent. Assoc. 56, 13-21. Kakar R. C. and Subramanian V. (1963) Sealing qualities of various restorative materials. J. Prosthet Dent. 13, 156-165. Loiselle R. J., Goldberg A. F., Gross R. L. et al. (1969) Marginal leakage-an in vivo assessment. J. Am. Dent. Assoc. 78, 758-760. McCurdy C. R., Swartz M. L., Phillips R. W. et al. (1974) A comparison of in vivo and in vitro microleakage of dental restorations. J. Am. Dent. Assoc. 88, 592-602. Myer J. M., Dennison J. B. and Craig R. G. (1974) Improved method of neutron activation analysis for microleakage studies. J. Dent. Res. 53, 356-363. Pickard H. M. and Gayford J. J. (1965) Leakage at the margins of amalgam restorations. Br. Dent. J. 119, 69-77. Wright W., Mazer R. M., Leinfelder K. F. ef al. (1988) Effect of cavity varnish on the clinical microleakage of amalgam. J. Dent. Res. 67, (abstr. 308), 139.
Abstracts
Hydrodynamisches Verhalten der Dentin-TubulusFliissigkeit unter okklusaler Belastung. (Hydrodynamic behaviour of the tubular fluid in dentine under occlusal load.) Lutz F., Krejci I., lmfeld Th. et al. (1991) Schweiz. Monatsschr. Zahnmed. 101, 24-30. In an in vitro study, the fluid movements were quantitatively recorded in natural teeth incorporated rigidly in a closed measuring system and exposed to an occlusal load of 122.6 N. Fluid movements under load are the result of elastic deformations of the tooth. Occlusal loads which were repeated within a short period of time caused a reversible plastic deformation. In comparison to the unfilled tooth the placement of an
MOD restoration combined with a glass ionomer cement base caused the following alterations in fluid movements: composite inlay, - 3.1 per cent; the placement of the base per se induced a reduction of - 24.7 per cent; ceramic inlay, + 34.7 per cent; MOD amalgam, - 12.7 per cent. In this in vitro study, the physical properties of the restorative materials governed the magnitude of the fluid movements under load. The results are in contradiction to clinical findings and favour the pulpitisrelated genesis of postoperative sensitivity. The intratubular and intrapulpal fluid movements under occlusal load seem to trigger the pain sensation. (24 references) Author’s abstract selected by W. Kullmann
J. Dent.
1992;
20:
No. 1
restoration/tooth interface. The radioisotope technique generally indicated a greater degree of leakage than did the ultraviolet dye technique. This should not be construed, however, to mean that the radioisotope test is necessarily more discerning than the ultraviolet dye test. For example, the radioisotope test did not detect a significant difference between the ‘No treatment’ and Copalite groups at the occlusal margin that was detected by the ultraviolet dye test. This outcome occurred, in large measure, because the differences in degrees of leakage detected by the two tests were not consistent for all groups. Future research should be directed toward attempting to determine if these inconsistencies extend to other microleakage detection tests. The possibility that testing order may affect the outcome should also be examined. In this study, the specimens were first exposed to the radioisotope and then, in a separate step, were exposed to the ultraviolet dye. This was intentionally done to prevent dye contamination of the radioisotope solution. Ideally specimens should be exposed to both media simultaneously to prevent testing order from having an effect on the outcome. Microleakage detection tests have played an important role in dental research and have enabled investigators to assess the ability of restorative materials to seal the restoration/tooth interface. The results of this study suggest, however, that individual tests do not yield equivalent results and that they should not be considered to be interchangeable.
International
References Christen A G. and Mitchell D. F. (1966) A fluorescent dye method for demonstrating leakage around dental restorations. J. Dent. Res. 45, 1485-1492. Crim G. A., Swartz M. L. and Phillips R. W. (1985) Comparison of four thermocycling techniques. J. Prosthet Dent. 53, 50-53. Going R. E. (1972) Microleakage around dental restorations: a summarizing review. J. Am. Dent Assoc. 84, 1349-1357. Granath L. (1967) Studies on microleakage with restorative materials. Part I. Introductory experiments on amalgam. J. Dent Res. 46, 1331-1336. Guzman H. J., Swartz M. L. and Phillips R. W. (1969) Marginal leakage of dental restorations subjected to thermal stress. J. Prosthet Dent. 21, 166-175. Hirsch L. and Weinreb M. M. (1958) Marginal fit of direct acrylic restorations. J. Am. Dent. Assoc. 56, 13-21. Kakar R. C. and Subramanian V. (1963) Sealing qualities of various restorative materials. J. Prosthet Dent. 13, 156-165. Loiselle R. J., Goldberg A. F., Gross R. L. et al. (1969) Marginal leakage-an in vivo assessment. J. Am. Dent. Assoc. 78, 758-760. McCurdy C. R., Swartz M. L., Phillips R. W. et al. (1974) A comparison of in vivo and in vitro microleakage of dental restorations. J. Am. Dent. Assoc. 88, 592-602. Myer J. M., Dennison J. B. and Craig R. G. (1974) Improved method of neutron activation analysis for microleakage studies. J. Dent. Res. 53, 356-363. Pickard H. M. and Gayford J. J. (1965) Leakage at the margins of amalgam restorations. Br. Dent. J. 119, 69-77. Wright W., Mazer R. M., Leinfelder K. F. ef al. (1988) Effect of cavity varnish on the clinical microleakage of amalgam. J. Dent. Res. 67, (abstr. 308), 139.
Abstracts
Hydrodynamisches Verhalten der Dentin-TubulusFliissigkeit unter okklusaler Belastung. (Hydrodynamic behaviour of the tubular fluid in dentine under occlusal load.) Lutz F., Krejci I., lmfeld Th. et al. (1991) Schweiz. Monatsschr. Zahnmed. 101, 24-30. In an in vitro study, the fluid movements were quantitatively recorded in natural teeth incorporated rigidly in a closed measuring system and exposed to an occlusal load of 122.6 N. Fluid movements under load are the result of elastic deformations of the tooth. Occlusal loads which were repeated within a short period of time caused a reversible plastic deformation. In comparison to the unfilled tooth the placement of an
MOD restoration combined with a glass ionomer cement base caused the following alterations in fluid movements: composite inlay, - 3.1 per cent; the placement of the base per se induced a reduction of - 24.7 per cent; ceramic inlay, + 34.7 per cent; MOD amalgam, - 12.7 per cent. In this in vitro study, the physical properties of the restorative materials governed the magnitude of the fluid movements under load. The results are in contradiction to clinical findings and favour the pulpitisrelated genesis of postoperative sensitivity. The intratubular and intrapulpal fluid movements under occlusal load seem to trigger the pain sensation. (24 references) Author’s abstract selected by W. Kullmann