The Affect Of Carbamide Peroxide Bleaching Agent On The Four Kinds Of Composite Resin Surface Roughness And Micro Hardness

Objective:To research the effects of Carbamide peroxide bleaching agent on four kinds of composite resin surface roughness and micro hardness.Methods:Four selected common clinical composite resin materials were prepared for each resin diameter 15mm, thickness 1mm specimens, then polymerizated, maintained for seven days at 37℃,100% relative humidity. All samples have randomly devided into two parts, study and control group experimental group bleaching agent (peroxide) on the sample processing, the control group, deionized water. Detected the changes of four types of composite resin surface roughness and micro hardness at different time points (0 days,7 days,14 days,21 days,28 days). Used SEM to investigate 0 and 28 days experimental group and control group ultrastructural changes. Statistical analysis the the effects of Carbamide peroxide bleaching agent on four kinds of composite resin surface roughness and micro hardness.Results:1. Test four kinds of surface roughness of composite resin, statistical results showed that the roughness of bleach or not the material had no significant effect (P=0.897).2. Test four kinds of resin surface microhardness, discover four composite resin as time increases, various materials microhardness is a downward trend. DAP and the Z100 by bleaching in the experimental group the decrease of micro-hardness than the control group, particularly to micro-hardness of DAP softening increased with time, Z350 and Z250 in the experimental group dropped its micro-hardness than the control group. Z100 micro-hardness in the experimental group is the most, followed by the Z250, DAP and Z350. The smallest DAP and Z350 have no significant difference (P= 0.988). The control group, Z100 is also the largest micro-hardness, and then the orde are Z250, DAP, the smallest is the Z350.3. Observation of the experimental group and control group of the microscopic structural changes with SEM, found in the first 28 days DAP experimental and control groups have emerged cracks, it also can see a white cube packing loss and many cracks and circular holes. Experimental group than in the control group, more hollow and the loss of filler particles.Conclusion:1. Carbamide peroxide bleaching agent does not cause four kinds of surface roughness of composite resin materials significant changes.2. Four kinds of composite resin material with time increase the micro-hardness are shown a downward trend, DAP and the Z100 by bleaching in the experimental group the decrease of micro-hardness than the control group, particularly to micro-hardness of DAP softening increased with time, Z350 and Z250 in the experimental group dropped its micro-hardness than the control group.3. Carbamide peroxide bleaching agent on the four kinds of composite resin materials, the surface can cause significant changes, including cracks, holes, resin matrix and filler between the damage.