Accuracy and Reliability of Space Analysis Measurements in Digital Models with Different Degrees of Crowding

Table 2: Arch length, tooth size and TALD, Overall Bolton and Anterior Bolton ratios for both plaster and digital models.

-	Arch	Plaster (N=40)	Digital (N=40)	Mean Differences Plaster - Digital	p value (Plaster vs Digital)
Arch Length Mean (SD)^a	Maxillary	69.09 (4.18)	69.54 (4.60)	-0.45	*
Arch Length Mean (SD)^a	Mandibular	61.86 (4.02)	61.57 (4.69)	0.29	NS
Tooth Width Mean (SD)^a	Maxillary	73.15 (3.41)	74.29 (3.25)	-1.14	**
Tooth Width Mean (SD)^a	Mandibular	66.04 (2.51)	66.57 (2.89)	-0.53	*
TALD Mean (SD)^a	Maxillary	4.06 (3.06)	4.75 (3.45)	-0.69	**
TALD Mean (SD)^a	Mandibular	4.18 (2.94)	5.00 (3.44)	-0.82	**
Overall Bolton Ratio Mean (SD)^b	-	93.24 (2.30)	92.65 (2.31)	0.59	**
Anterior Bolton Ratio Mean (SD)^b	-	79.77 (3.09)	79.42 (2.37)	0.35	NS

^a Units are represented in millimeters;
^b Units are represented in percentage; TALD reported in absolute value; p value based on a paired t-test: *p < 0.05; **p < 0.01; NS = Non-Significant. Difference plaster - digital = (+) plaster is larger; (-) digital is larger.