Experimental Study Of The Influence Of Methylcellulose On The Mechanical Performance On Dental Stones

Objectives:To study the influence of methylcellulose with different concentration on anti-bending strength and dimensional changes of dental stones.The concentration of methylcellulose is 0.01%,0.02%,0.03%,0.04%,0.05% respectively.Methods:The dental stones were divided into two groups, the control group was mixed with distilled water and the experimental group was mixed with 5 kinds of concentrations of methylcellulose solution. Dental stones were made by mixing of methylcellulose with different concentration(the experiment group) or distilled water(the control group) and dental stone powder in vacuum mixer for 40s,and then were poured into the block mould,1 hour later, the models were demolded and dry up for 72 hours naturally indoor. The bending resistance was tested with the universal testing machine, and the dimensional sizes of the gypsum casts were measured by measuring the distances between landmark points on the plaster model surfaces using universal tool microscope.Results:When the concentration of methylcellulose were 0.01%,0.04% or 0.05%,the bending resistance was reduced, but this difference was not statistically significant (p>0.05) and the dimensional accuracy was not affected (p>0.05);when the concentration of methylcellulose was 0.03%,the bending resistance was increased, but no significant difference compared with the control group (p>0.05);when the concentration of methylcellulose was 0.02%,the bending resistance obviously exceeded the control group and showed significant differences (p<0.05), but the dimensional accuracy was not affected(p>0.05). Conclusion:when its concentration was 0.02% the methylcellulose increased the bending resistance obviously and the dimensional accuracy was not affected.