Compliance with the ISO 27020:2019 norm of a sample of currently available preadjusted Orthodontic bracket systems. Are the actual dimensions as expected?

Table 1 Bracket slot height in the analysed systems. In boldface the systems with a mean slot height out of ISO 27020:2019 tolerance limit

Bracket system	N	Mean (± SD)	Min	Max	MD	Z_W	p
SYNTHESIS	30	0.556(± 0.004)	0.554	0.559	-0.003	-4.616	< 0.001***
NU-EDGE	30	0.574(± 0.010)	0.559	0.591	0.015	-4.784	< 0.001***
DISCOVERY	30	0.570(± 0.010)	0.558	0.590	0.011	-4.476	< 0.001***
FLI TWIN	30	0.566(± 0.008)	0.558	0.590	0.007	-4.560	< 0.001***
MINI SPRINT	30	0.567(± 0.005)	0.558	0.577	0.008	-4.705	< 0.001***
OMNIARCH +	30	0.560(± 0.002)	0.555	0.567	0.001	-2.575	0.010**
SCAPE	30	0.562(± 0.006)	0.558	0.571	0.003	-3.564	< 0.001***
MINI-TWIN	30	0.554(± 0.005)	0.542	0.562	-0.005	-3.924	< 0.001***
JAZZ	30	0.548(± 0.009)	0.528	0.560	-0.011	-4.456	< 0.001***
MINI MASTER	30	0.548(± 0.005)	0.540	0.559	-0.011	-4.766	< 0.001***
MINIPREVAIL	30	0.560(± 0.004)	0.552	0.570	0.001	-1.763	0.078
VICTORY	30	0.560(± 0.001)	0.558	0.563	0.001	-3.953	< 0.001***

SD Standard deviation; Min Minimum slot height; Max Maximum slot height; MD Mean difference between nominal and actual values; Z_W Wilcoxon standardized rank; Wilcoxon test *p ≤ .05; **p < .01; ***p < .001

ISSN: 1746-160X