Kan afbindingstiden for konventionelle glasionomercementer forkortes ved belysning?
Konventionel glasionomercement har en initial afbindingstid som skal afventes inden restaureringen kan færdiggøres. Under den initiale afbinding skal cementoverfladen beskyttes mod udtørring og vandkontakt. Det er blevet foreslået at forkorte afbindingstiden ved at tilføre cementen varme ved belysning med en lyspolymerisationslampe. Der er i øvrigt markedsført en særlig glasionomercement (Fuji VII) med dette for øje. Det var hensigten med denne undersøgelse at bestemme effekten af varmetilførsel på afbindingstiden af fem konventionelle glasionomercementer. Uden belysning varierede afbindingstiden mellem 2 min. 30 sek. og 3 min. 30 sek. Efter belysning varierede afbindingstiden mellem 2 min. 10 sek. og 2 min. 30 sek. Belysning medførte forkortelse af afbindingstiden for fire af de fem cementer. Effekten steg med belysningens varighed og med den anvendte lampes intensitet og dermed varmeudvikling.
Can the setting time of conventional glass ionomer cements be reduced by light exposure? Conventional glass ionomer cements are characterized by an initial setting time during which the cement is susceptible to water uptake and to dehydration. Application of heat from a light-curing unit has been suggested as a means to obtain command set of these cements, and a glass ionomer cement has been developed and marketed specifically for utilizing this principle. It was the aim of this study to determine the effect of application of heat via exposure to light from a curing unit on the setting time of five conventional glass ionomer cements. Without light exposure, the setting time varied between 2 min. 30 sec. and 3 min. 30 sec. Following light exposure, the setting time varied between 2 min. 10 sec. and 2 min. 30 sec. Light exposure reduced the setting time of four out of five cements. The effect of light exposure increased with exposure time and with power density of the curing unit and thus with the applied heat.
