IADR Abstract Archives
Wear Properties of Experimental MFR Composite(NGD220) for Posterior Restoration
Objectives: Physical properties of composite resin are considered to be important for the posterior restoration. However, extremely strong material may cause to damage the antagonistic tooth. We investigated the wear properties of composite in the viewpoint of both material and tooth abrasion.
Methods: The trial composite(NGD220) was compared with Z100(3M) known as the micro-hybrid composite. Each composite was light-cured and the effective surface area was 3.46 mm2. The specimens were contacted to the bovine enamel with a load of 11.56 kg/cm2, and then reciprocated horizontally on the enamel surface over a 2 cm path at a rate of 100 strokes per minute. The specimens and the bovine teeth were immersed in distilled water without any abrasive powders during the wear test. After 200,000 cycles, the wear of composite was investigated by height loss. The enamel abrasion was evaluated with the equipment for measuring the surface roughness.
Results: The mean value for each site was compared by One Way ANOVA and is shown below.
|
Wear Properties |
General Properties |
|||
|
Material wear [ µm] |
Enamel abrasion [ µm] |
Surface roughness [ µm] |
Vickers hardness [kg/mm2] |
|
|
NGD220 |
6.0(3.5) |
4.1(2.0) |
0.30(0.06) |
38.2(2.8) |
|
Z100 |
131.6(41.1) |
55.6(10.3) |
0.50(0.05) |
112.3(3.5) |
(S.D.)
Conclusion: The differences between these materials are statistically significant(p<0.01). It is suggested that NGD220 hardly wears and doesn
't damage the antagonistic tooth. As for Z100, once the material surface is abraded, it seems that fillers are continuously falling out and the surface becomes rougher. Consequently, the rougher surface damages the enamel more, which may cause the tooth attrition by the occlusion. NGD220 contains the fluoro-alumino-silicate glass(ionomer glass) and the pre-polymerized filler. These fillers are smooth and not too hard, therefore, NGD220 is compatible with the teeth.