MECHANICAL PROPERTIES OF THE NEW KETAC™ UNIVERSAL GLASS IONOMER RESTORATIVE MATERIAL: EFFECT OF RESIN COATING

Statement of the problem: Clinical performance and survival rates of posterior high strength GICs are questionable. A new generation of conventional glass-ionomer restorative material
(Ketac™ universal) without coating has been launched recently for restoring class I and II cavities without investigations.
Objectives: This study was conducted to evaluate the mechanical properties of a new generation of conventional glass ionomer (Ketac™ universal) for restoring posterior stress bearing areas.Furthermore, the effectiveness of resin coating on Ketac™ universal GIC was evaluated.
Materials and Methods: Three types of conventional glass ionomer restorative materials were selected for this study (Ketac™ Universal; KU, Ketac™ Molar; KM and Fuji IX GpFast; FIXF). Each GICs material specimens were prepared according to manufacturer’ instructions and distributed randomly into two groups (N=30) (uncoated and coated groups) and then conditioned in distilled waterat 370C for 24 hours. The flexural strength,compressive strength, and hardness tests for each material were evaluated using a universal testing machine. Furthermore, additional representative un-coated and coated specimens for each material were prepared for their characterization under scanning electron microscope. Data were analysed by multivariate ANOVA. Bonferroni post hoc test was used for multiple comparisons. Paired t-test was used to detect significant differences between un-coated and coated GICs. Interactions between GICs materials and coating were also performed. P-value is significant if it was less than .05.
Results: The highest significant flexural strength, compressive strength and hardness values were noticed with Ketac universal and the lowest was noted with FIXF. Also, only significant improvement in the flexural and compressive strength of FIXF when resin coating was applied.
Conclusions: KU represents an encouraging line of higher clinical longevity of GICs’ filling material in stress bearing areas. Also the resin coating has no significant effect on the tested mechanical properties of KU GICs.