Table 3

Variable	S group	M group	GM group	S vs. M	S vs. GM	M vs. GM
Variable	Mean (SD) in mm			P-value
Total
ΔHVC	-2.13 (0.18)	-0.58 (0.12)	-0.31(0.05)	< 0.0001^a	< 0.0001^a	0.0117^b
ΔHLC	-2.06 (0.2)	-0.52 (0.11)	-0.43 (0.08)	< 0.0001^a	< 0.0001^a	0.201^b
ΔRW	-3.96 (0.87)	-1.21 (0.69)	-0.91 (0.53)	< 0.0001^a	< 0.0001^a	0.0342^b
Premolar
ΔHVC	-2.07 (0.6)	-0.67 (1.12)	-0.69 (0.79)	< 0.0001^a	< 0.0001^a	0.2588^b
ΔHLC	-2.34 (0.76)	-0.58 (1.40)	-0.52 (0.06)	< 0.0001^a	< 0.0001^a	0.2439^b
ΔRW	-3.51 (0,39)	-0.58 (1.97)	-0.47 (1.13)	< 0.0001^a	< 0.0001^a	0.0251^b
Molar
ΔHVC	-2.16 (0.03)	-1.16 (0.08)	-0.67 (0.07)	< 0.0001^a	< 0.0001^a	< 0.0001^a
ΔHLC	-2.09 (0.73)	-1.24 (0.48)	-0.59 (0.26)	< 0.0001^a	< 0.0001^a	< 0.0001^a
ΔRW	-4.27 (0.29)	-1.21 (0.81)	-0.75 (0.44)	< 0.0001^a	< 0.0001^a	< 0.0001^a

^aStatistically significant at P ≤ 0.05 (Kruskal-Wallis test).
^bStatistically significant at P > 0.05 (Kruskal-Wallis test).
SD = standard deviation; ΔRW = changes in ridge width, ΔHVC = changes in height of the vestibular crest, ΔHLC = changes in height of the lingual crest; S = spontaneous healing; M = porcine-derived collagen membrane alone; GM = porcine-derived graft material associated with collagen membrane.