Abstract
This study evaluated the effects of polishing after 24-hour storage in water on the gap formation around Class V restorations (n=10, 14 points, total points measured= 140) using one conventional glass-ionomer for high powder-liquid ratio (Fuji IX GP, GC), one resinmodified glass-ionomer for high powder-liquid ratio (Fuji VIII, GC), and one conventional glass-ionomer (Fuji II, GC) and one resin-modified glass-ionomer (Fuji II LC, GC) as controls. This study also examined the shear bond strength to enamel substrate and to dentin substrate and flexural strength of these restorative materials, which may influence the gap formation.
When the specimens of the four types of glass-ionomer material were polished immediately after the setting procedure, 80-120/140 (14 points × 10 cavities) gaps around the Class V restorative cavity were observed. In contract, only 10-20/140 gaps were observed when the specimens were polished after one-day storage. Significant differences in the four glassionomer restorative materials were observed between immediate polishing and polishing after one-day storage.
Bond strength and flexural strength played important roles in reducing the gap formation in Class V restorative cavity with four glass-ionomer restorative materials. In contract, the effect of the high powder-liquid ratio did not play an important role in reducing the gap formation for conventional and resin-modified glass-ionomer restorative materials.
