Table 5.

Adjust GEE model for water uptake based on retainer type and time

Covariate	Coef	95% conf. interval	P value
Time
0 h* (base comparison)	Reference
12 h	0.010	(0.009 to 0.011)	< 0.001
24 h	0.014	(0.012 to 0.015)	< 0.001
1 m	0.017	(0.015 to 0.019)	< 0.001
3 m	0.018	(0.017 to 0.020)	< 0.001
6 m	0.017	(0.015 to 0.019)	< 0.001
Brand
Duran 1* (base comparison)	Reference
Duran 1.5	0.114	(0.103 to 0.125)	< 0.001
Essix C +	− 0.061	(− 0.065 to − 0.056)	< 0.001
Vivera	− 0.011	(− 0.014 to − 0.008)	< 0.001
Zendura	0.022	(0.020 to 0.024)	< 0.001
State
Thermoformed* (base comparison)	Reference
Worn	− 0.002	(− 0.006 to 0.002)	0.265
Solution
Water* (base comparison)	Reference
Artificial saliva	− 0.001	(− 0.003 to 0.001)	0.394