Effects of simulated intraoral temperatures and wet environments on the stress relaxation properties of thermoplastic aligner materials

Table 4 Residual stress of the five material after 2 weeks liquid immersion

normalized residual stress (%)	Biolon	Duran	Erkodur	Essix ACE	Essix C +
control	89.0 ± 1.4^Aa	91.9 ± 0.0^Ab	92.3 ± 0.3^Ab	89.3 ± 0.7^Aa	67.7 ± 0.3^Ac
deionized water	91.5 ± 0.1^Aa	91.9 ± 0.8^Aa	92.0 ± 1.6^Aa	92.2 ± 0.7^Ba	67.1 ± 1.6^Ab
artificial saliva	91.3 ± 0.4^Aa	92.2 ± 0.3^Aab	92.6 ± 1.2^Aab	93.1 ± 0.2^Bb	67.6 ± 0.5^Ac

The values are represented as the mean ± standard deviation, for their normal distribution
Normalized residual stress = residual stress/initial stress
Upper case (AB) represents column, lower case represents row(ab), same letter represents no significant difference among groups (P > 0.05)

ISSN: 1746-160X