Group
Demographics and dependent variables S M GM
Patient (n) 9 9 8
Age (years) 21 - 56 19 - 60 20 - 63
Sex (male/female) 5/4 3/6 6/2
Premolar/molar 4/5 6/3 4/4
Smoking habit (yes/no) 2/7 3/6 3/5

n = number; S = spontaneous healing; M = porcine-derived collagen membrane alone; GM = porcine-derived graft material associated with collagen membrane.