Physical properties of dental floss made from Thai natural silk

Methods: Seven commercial dental flosses were used to examine the tensile strength and %elongation for comparison with 5 brands of Thai natural silk (nang-noi, lotus, samchai, sakon and jaroon). Silk were prepared at 800-850 deniers and divided into 2 groups; uncoated and wax-coated. The experiment was performed according to ASTM D 885-06(2006) standard using universal testing machine (n=20). ANOVA and Tamhane's T multiple comparison was used to analyzed the difference between groups while t-test was used to compare the effects of wax on the properties of natural Thai silk. (á=0.05)

Results: commercially dental flosses had the maximum tensile strength in the range of 2.56-50.70N and elongation in the range of 7.69-53.96%. The maximum tensile strength of Thai natural silks ( nang-noi, lotus, samchai, sakon and jaroon) in un-waxed group was 14.5±1.4, 16.9±7.2, 24.2±6.5, 22.5±8.1 and 17.6±1.6 N and elongation was 8.0±0.6, 8.8±2.6, 11.5±1.7, 9.8±1.5 and 9.2±1.5% respectively. In waxed groups, the maximum tensile strength was 20.4±2.8, 16.8±2.7, 19.1±2.3, 18.4±1.7 and 18.6±1.2 N respectively and elongation was 11.5±1.5, 13.3±2.4, 23.9±7.0, 14.6±2.7 and 11.9±1.6% respectively. Wax coating procedure could change both properties of most experimental silk significantly excepted for Lotus silk which showed no difference of elongation and Jaroon silk which showed no difference of maximum tensile strength. Within the waxed group, Nangnoi silk had the highest tensile strength while Samchai silk had the highest percentage of elongation.

Conclusion: Dental floss made from Thai natural silk which was processed by wax coating had the maximum tensile strength and the percentage of elongation in the same range of commercial dental flosses. Nang-noi silk had the highest maximum tensile strength and Sam-chai silk had the highest percentage of elongation.