Mechanical Characterization of Thermoplastic Aligner Materials: Recommendations for Test Parameter Standardization

Table 3

Measured average, maximum (max.), and minimum (min.) thicknesses for thermoformed specimens (TF) using the different thermoforming forms. The original foil thickness represents the thickness given by the manufacturer, and the measured thickness represents the thickness measured by the micrometer gauge. Thickness reduction due to thermoforming is given as a percentage value.

Original foil thickness (mm)	Before thermoforming			TF with flat metal plate			TF with stone model base			TF with round stone disc			TF with stone roof form
	Thickness (mm)	Max.	Min.	Thickness (mm)	Max.	Min.	Thickness (mm)	Max.	Min.	Thickness (mm)	Max.	Min.	Thickness (mm)	Max.	Min.
0.4	0.42	0.42	0.40	0.38	0.39	0.37	0.35	0.38	0.33	0.38	0.38	0.37	0.35	0.36	0.34
0.5	0.56	0.56	0.55	0.51	0.51	0.50	0.45	0.46	0.44	0.50	0.51	0.48	0.45	0.46	0.44
0.625	0.63	0.63	0.63	0.60	0.60	0.59	0.54	0.55	0.54	0.58	0.60	0.56	0.52	0.52	0.51
0.75	0.77	0.77	0.77	0.72	0.73	0.71	0.68	0.70	0.65	0.74	0.74	0.73	0.65	0.65	0.64
Average reduction				−8%			−15%			−8%			−17%