Table 10.

Separation of the study individuals into four classified PCA groups.

	All	Resins, Fick	Composites, Fick	Resins, Dual	Composites, Dual
Individual number	448	56	98	147	147
Initial variables number	8	6	7	11	12
Individual variance of each initial variable	$12.5\%$	$16.7\%$	$14.3\%$	$9.1\%$	$8.3\%$
Min. number of PC for an overview	6 ($92.4\%$)	4 ($85\%$)	4 ($79.6\%$)	5 ($76.3\%$)	6 ($79.4\%$)