title: Glass-ionomer cement film thickness and working time.
abstract: Reports on film thickness for adhesive glass-ionomer cements have not been consistent, and confusion exists relative to proper working times. In this investigation, film thickness was measured over a range of times for three glass-ionomer cements by using a traditional ADA glass plate technique and a simulated clinical cementation technique with castings and dies. The cements were examined from 60 seconds to 255 seconds from the start of mix. Results indicated that the simulated clinical technique generally provided less film thickness. No significant differences in film thickness were found between the brands of cement through 240 seconds with film thickness ranging from 7.24 to 20.5 microns. Greater differences between the cements were observed with the ADA technique beyond 135 seconds from the time of mix. Relative to film thickness, working times would appear to be greater than previously reported for glass-ionomer cements.
authors.affiliation: Wilford Hall United States Air Force Medical Center, San Antonio, Tex.
authors.forename: D M
authors.initials: DM
authors.lastname: Kyrios
authors.forename: E S
authors.initials: ES
authors.lastname: Duke
authors.forename: A S
authors.initials: AS
authors.lastname: Windeler
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003738:Dental Cements; D005899:Glass Ionomer Cements; D008277:Magnesium Oxide; D011076:Polycarboxylate Cement; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D015034:Zinc Oxide
chemical_list: D003738:Dental Cements; D005899:Glass Ionomer Cements; D011076:Polycarboxylate Cement; C062270:Shofu Hybond; D008277:Magnesium Oxide; C037885:Fuji-ionomer; C040235:Ketac-cem; D015034:Zinc Oxide