Skip to main content

Table 1 National bureau of standards ratings

From: Colorimetric and spectrophotometric measurements of orthodontic thermoplastic aligners exposed to various staining sources and cleaning methods

National Bureau of Standards unitsDescription of color change
0.0–0.5Trace: extremely slight change
0.5–1.5Slight: slight change
1.5–3.0Noticeable: perceivable
3.0–6.0Appreciable: marked change
6.0–12.0Much: extremely marked change
12.0 and moreVery much: change to other color