The Effect of Lucite Glass Reinforcement on the Properties of Conventional Glass-Ionomer Filling Materials

Statement of the problem: the usage of glass ionomer cements (gics) restorative materials are very limited due to lack of flexural strength and toughness. purpose: the aim of this study was to investigate the effect of using a leucite glass on a range of mechanical and optical properties of commercially available conventional glass ionomer cement. materials and method: ball milled 45μm leucite glass particles were incorporated into commercial conventional gic, ketac-molar easymix (kmem). the characteristics of the powder particles were observed under scanning electron microscopy. the samples were made for each experimental group; kmem and lucite- modified ketac- molar easy mix (lmkmem) according to manufacturer’s instruction then were collected in damp tissue and stored in incubator for 1 hour. the samples were divided into two groups, one stored in distilled water for 24 hours and the others for 1 week.10 samples were made for testing biaxial flexural strength after 1 day and 1 week, with a crosshead speed of 1mm/min, calculated in mpa. the hardness (vickers hardness tester) of each experimental group was also tested. to evaluate optical properties, 3 samples were made for each experimental group and evaluated with a spectrophotometer. the setting time of modified gic was measured with gillmore machine. result: the setting time in lmkmem was 8 minutes. the mean biaxial flexural strength was lmkmem/ 1day: 24.13±4.14 mpa, lmkmem/ 1 week: 24.22±4.87 mpa kmem/1day:28.87±6.31 mpa and kmem/1 week: 26.65±5.82 mpa which were not statistically different from each other. the mean vickers hardness was lmkmem: 403±66 mpa and kmem: 358±22 mpa; though not statistically different from each other. the mean total transmittance (tt) was lmkmem: 15.9±0.7, kmem: 22.3±1.2, the mean diffuse transmittance (td) was lmkmem: 12.2±0.5, kmem: 18.0±0.5 which were statistically different from each other. conclusion: leucite glass can be incorporated with a conventional gic without interfering with setting time. yet, it did not improve the mechanical and optical properties of the gic.