Table 5.

Estimated means and standard deviations of volumetric distortion according to MAR algorithm and windowing adjustment obtained for the two CBCT units

CBCT unit	Material	MAR	Windowing
			W1 (SD)	W2 (SD)	p valuea
Picasso	Am	Off	12.45 (4.73)	26.04 (3.41)	p < 0.01
		On	12.28 (2.48)	20.52 (2.47)	p < 0.01
		p valueb	1.00	0.14
	CoCr	Off	10.37 (8.38)	15.79 (4.06)	0.16
		On	6.96 (2.79)	11.58 (2.4)	0.43
		p valueb	0.9	0.62
	Gu	Off	1.15 (4.87)	19.28 (6.76)	p < 0.01
		On	−12.88 (6.33)	−7.73 (5.03)	0.23
		p valueb	p < 0.05	p < 0.05
	Ti	Off	3.84 (7.85)	19.35 (4.97)	p < 0.01
		On	−11.58 (2)	−7.1 (3.24)	0.5
		p valueb	p < 0.01	p < 0.01
	Zi	Off	10.9 (7.46)	23.44 (4.12)	p < 0.01
		On	6.12 (1.76)	12.81 (1.29)	p < 0.05
		p valueb	0.37	1.00
OP300	Am	Off	41.01 (2.42)	47.93 (4.7)	0.14
		On	53.37 (5.65)	66.99 (3.85)	p < 0.01
		p valueb	p < 0.01	p < 0.01
	CoCr	Off	35.22 (5.29)	39.74 (5.29)	0.86
		On	52.84 (5.03)	62.09 (2.97)	p < 0.01
		p valueb	p < 0.01	p < 0.01
	Gu	Off	27.81 (5.34)	37.86 (4.35)	p < 0.01
		On	28.68 (5.35)	39.91 (7.69)	p < 0.01
		p valueb	1.00	1.00
	Ti	Off	28.31 (4.57)	40.8 (2.49)	p < 0.01
		On	33.83 (12.67)	48.79 (7.47)	p < 0.01
		p valueb	0.54	p < 0.01
	Zi	Off	36.78 (2.02)	47.81 (3.51)	p < 0.01
		On	50.34 (5.28)	63.56 (5.35)	p < 0.01
		p valueb	p < 0.01	p < 0.01

Am, amalgam alloy; CBCT, cone-beam computed tomography; CoCr, cobalt-chromium; Gu, gutta-percha; MAR, metal artefact reduction; SD, standard deviation; Ti, titanium; W1, large window width and upper window level; W2, narrow window width and low window level; Zi, zirconium.

Bold p-values indicate statistically significant differences (p < 0.05).

^ap-value corresponding to comparisons between W1 and W2 considering the same MAR condition.

^bpvalue corresponding to comparisons between MAR algorithm conditions considering the same windowing adjustment.