Biomechanical aging behaviour of clear aligners

Figure 1.

Figure 2.

Figure 3.

Translucency and surface roughness of clear aligners did not change significantly during the 21-day study (P > 0_05 for all, n = 3 in each group)

Translucency Parameter					Roughness – internal surface (μm)				Roughness – external surface (μm)
		Lower	Upper			Lower	Upper			Lower	Upper
Day	Mean±SD	95% CI	95% CI	P-value	Mean±SD	95% CI	95% CI	P-value	Mean±SD	95% CI	95% CI	P-value
0	3.69 ± 0.66	2.05	5.34	P > 0.05	5.53 ± 0.26	4.89	6.17	P > 0.05	1.34 ± 0.04	1.23	1.44	P > 0.05
1	4.97 ± 3.32	-3.27	13.20	P > 0.05	5.30 ± 0.23	4.74	5.87	P > 0.05	1.53 ± 0.10	1.28	1.77	P > 0.05
2	4.31 ± 4.25	-6.24	14.86	P > 0.05	5.64 ± 0.8	3.65	7.64	P > 0.05	1.72 ± 0.06	1.58	1.87	P > 0.05
3	3.10 ± 1.84	-1.47	7.67	P > 0.05	5.65 ± 0.67	3.97	7.32	P > 0.05	1.44 ± 0.50	0.19	2.69	P > 0.05
4	4.93 ± 2.91	-2.30	12.17	P > 0.05	5.39 ± 0.41	4.37	6.4	P > 0.05	1.60 ± 0.54	0.27	2.93	P > 0.05
5	4.85 ± 0.91	2.58	7.12	P > 0.05	5.33 ± 0.58	3.9	6.77	P > 0.05	1.45 ± 0.30	0.7	2.2	P > 0.05
6	4.50 ± 1.59	0.54	8.46	P > 0.05	5.45 ± 0.49	4.24	6.65	P > 0.05	1.45 ± 0.25	0.84	2.07	P > 0.05
7	3.87 ± 0.75	2.01	5.73	P > 0.05	5.58 ± 0.21	5.05	6.1	P > 0.05	1.29 ± 0.19	0.82	1.75	P > 0.05
8	4.72 ± 0.35	3.86	5.59	P > 0.05	5.47 ± 0.49	4.25	6.68	P > 0.05	1.38 ± 0.50	0.14	2.62	P > 0.05
9	3.20 ± 1.59	-0.76	7.15	P > 0.05	5.27 ± 1.07	2.61	7.94	P > 0.05	1.48 ± 0.45	0.37	2.59	P > 0.05
10	2.35 ± 0.84	0.27	4.44	P > 0.05	5.23 ± 0.65	3.61	6.86	P > 0.05	1.65 ± 0.06	1.51	1.79	P > 0.05
11	3.89 ± 1.61	-0.11	7.89	P > 0.05	5.64 ± 0.03	5.55	5.73	P > 0.05	1.72 ± 0.05	1.59	1.85	P > 0.05
12	2.35 ± 0.19	1.86	2.83	P > 0.05	5.39 ± 0.19	4.92	5.87	P > 0.05	1.52 ± 0.13	1.2	1.84	P > 0.05
13	4.76 ± 1.43	1.20	8.32	P > 0.05	5.54 ± 0.08	5.33	5.74	P > 0.05	1.34 ± 0.51	0.07	2.61	P > 0.05
14	2.51 ± 1.06	-0.12	5.14	P > 0.05	5.45 ± 0.52	4.15	6.74	P > 0.05	1.55 ± 0.45	0.42	2.67	P > 0.05
15	2.53 ± 0.33	1.72	3.34	P > 0.05	5.80 ± 0.03	5.73	5.87	P > 0.05	1.27 ± 0.05	1.14	1.41	P > 0.05
16	3.62 ± 1.96	-1.24	8.49	P > 0.05	5.57 ± 0.52	4.27	6.86	P > 0.05	1.75 ± 0.25	1.14	2.36	P > 0.05
17	2.36 ± 0.39	1.40	3.32	P > 0.05	5.53 ± 0.19	5.07	6.00	P > 0.05	1.72 ± 0.10	1.46	1.98	P > 0.05
18	2.65 ± 1.30	-0.57	5.88	P > 0.05	5.78 ± 0.27	5.1	6.46	P > 0.05	1.63 ± 0.24	1.04	2.23	P > 0.05
19	5.97 ± 1.35	2.63	9.32	P > 0.05	5.41 ± 0.77	3.5	7.31	P > 0.05	1.81 ± 0.09	1.58	2.05	P > 0.05
20	3.75 ± 1.88	-0.91	8.41	P > 0.05	5.28 ± 0.78	3.34	7.21	P > 0.05	1.68 ± 0.18	1.23	2.14	P > 0.05
21	4.49 ± 0.75	2.64	6.34	P > 0.05	5.31 ± 0.78	3.36	7.25	P > 0.05	1.70 ± 0.25	1.07	2.32	P > 0.05

Tensile strength and maximum load of the clear aligners did not change significantly during the 21-day study (P > 0_05 for all, n=3 in each group)

Tensile strength (N/mm2)					Maximum load (N/mm2)
		Lower	Upper			Lower	Upper
Day	Mean±SD	95% CI	95% CI	P-value	Mean±SD	95% CI	95% CI	P-value
0	20.85 ± 1.08	18.18	23.53	> 0.05	104.26 ± 5.38	18.18	23.53	> 0.05
1	20.55 ± 2.75	16.17	24.92	> 0.05	102.74 ± 13.75	16.17	24.92	> 0.05
2	21.38 ± 3.38	16.00	26.76	> 0.05	106.89 ± 16.91	16.00	26.76	> 0.05
3	19.87 ± 3.10	14.93	24.80	> 0.05	99.34 ± 15.50	14.93	24.80	> 0.05
4	20.28 ± 2.44	16.41	24.16	> 0.05	101.42 ± 12.18	16.41	24.16	> 0.05
5	20.98 ± 3.20	15.88	26.08	> 0.05	104.91 ± 16.02	15.88	26.08	> 0.05
6	20.01 ± 2.61	15.85	24.16	> 0.05	100.05 ± 13.06	15.85	24.16	> 0.05
7	19.02 ± 0.48	18.26	19.78	> 0.05	95.11 ± 2.39	18.26	19.78	> 0.05
8	21.70 ± 3.90	15.49	27.91	> 0.05	108.50 ± 19.51	15.49	27.91	> 0.05
9	20.11 ± 3.01	15.32	24.91	> 0.05	100.57 ± 15.06	15.32	24.91	> 0.05
10	18.98 ± 4.34	12.07	25.88	> 0.05	94.89 ± 21.69	12.07	25.88	> 0.05
11	22.02 ± 2.46	18.10	25.93	> 0.05	110.08 ± 12.30	18.10	25.93	> 0.05
12	18.22 ± 3.48	12.67	23.76	> 0.05	91.08 ± 17.42	12.67	23.76	> 0.05
13	18.95 ± 2.84	14.43	23.46	> 0.05	94.74 ± 14.18	14.43	23.46	> 0.05
14	18.82 ± 1.56	16.33	21.31	> 0.05	94.08 ± 7.82	16.33	21.31	> 0.05
15	21.11 ± 2.61	16.95	25.26	> 0.05	105.53 ± 13.05	16.95	25.26	> 0.05
16	20.43 ± 4.67	13.01	27.85	> 0.05	102.15 ± 23.33	13.01	27.85	> 0.05
17	19.45 ± 3.11	14.51	24.40	> 0.05	97.27 ± 15.53	14.51	24.40	> 0.05
18	18.93 ± 0.32	18.41	19.44	> 0.05	94.65 ± 1.62	18.41	19.44	> 0.05
19	21.08 ± 1.75	18.29	23.86	> 0.05	105.38 ± 8.75	18.29	23.86	> 0.05
20	18.40 ± 2.80	13.94	22.86	> 0.05	91.99 ± 14.01	13.94	22.86	> 0.05
21	17.63 ± 3.58	11.94	23.32	> 0.05	88.17 ± 17.88	11.94	23.32	> 0.05