title: Relative microhardness of glass ionomer restorative materials as an indicator of finishing time.
abstract: Microhardness was evaluated as an indicator of appropriate finishing intervals for glass ionomer restorative materials. The hardness of several materials was determined after the first hour of mixing. A material clinically documented to be satisfactorily finished after a delay of 15 minutes attained 29% of its 24-hour hardness during that interval. Samples of the other materials finished on reaching this relative hardness, which differed from the manufacturers' suggested finishing delays, showed no differences in surface characteristics, appearance, or surface roughness compared with specimens finished at the recommended times.
authors.affiliation: Section of Restorative and Prosthetic Dentistry, Ohio State University, College of Dentistry, Columbus 43210-1241.
authors.forename: W W
authors.initials: WW
authors.lastname: Brackett
authors.forename: W M
authors.initials: WM
authors.lastname: Johnston
mesh_terms: D000538:Aluminum Silicates; D003738:Dental Cements; D003775:Dental Polishing; D003793:Dental Restoration, Permanent; D005069:Evaluation Studies as Topic; D005899:Glass Ionomer Cements; D006244:Hardness; D008298:Maleates; D012823:Silicate Cement; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000538:Aluminum Silicates; D003738:Dental Cements; D005899:Glass Ionomer Cements; D008298:Maleates; C054101:ChemFil II; D012823:Silicate Cement; C037885:Fuji-ionomer; C039733:Chemfil; C040964:Ketac-Fil