Color stability and force decay of clear orthodontic elastomeric chains: An in vitro study

OBJECTIVE: To compare the percentage force decay of clear and semi-clear elastomeric chain products from eight different manufacturers and to evaluate the amount of discoloration after immersion in colored dietary media of the same elastomeric chain products.

MATERIAL AND METHODS: An in vitro study was designed using an electronic force gauge to measure six samples from each of 19 types of elastomeric chains stretched for a period of four weeks. A spectrophotometer was used to measure the color of each specimen (10 of each type) at baseline and after being soaked in a dietary medium (coffee, tea, cola, and wine in 250 ml amounts) for 72 h.

RESULTS: There was a significant difference in the percentage of the lost initial force between all the tested E-chains (P<0.001). ANOVA shows a significant difference in the amount of discoloration between the E-chain types (P<0.001). Semi-clear (tooth-color/pearl/obscure) E-chain types (TP-ToothC, OrthO-Pearl, GAC-SiliPearl, 3M-Obscure) present significantly less change in color than clear E-chains of the same brand (TP-Clear, OrthoO-Clear, GAC-SiliClear, 3M-Clear).

CONCLUSIONS: Significant differences in the mean percentage force decay between the 19 studied clear elastomeric chain types were present. AO-Memory and Ormco maintained most of their original force at the end of the four-week interval. Significant differences in discoloration also exist between the various types of E-chains. TP Orthodontics (Tooth-Colored, SuperSlick, Clear) and Ortho Organizers (Pearl) showed the least discoloration.