Table 1 Frequency distributions and comparisons of baseline patient characteristics and local clinical features of the study groups

Age in years^a

65.4 (8.6)

66.9 (7.0)

64.0 (9.8)

0.253

Gender (female)

35 (74.5)

15 (65.2)

20 (83.3%)

0.154

Diabetes

18 (38.3)

9 (39.1)

9 (37.5)

0.908

Smokers and former smokers

28 (59.6)

13 (56.5)

15 (62.5)

0.676

 Well-rounded

3 (6.4)

2 (8.7)

1 (4.2)

0.175

 Knife-edge

19 (40.4)

6 (26.1)

13 (54.2)

 Flat ridge

8 (17.0)

6 (26.1)

2 (8.3)

 Depressed

17 (36.2)

9 (39.1)

8 (33.3)

 Buccal

2.02 (1.44)

1.76 (1.18)

2.27 (1.65)

0.230

 Lingual

1.88 (1.33)

1.48 (1.03)

2.27 (1.49)

0.040

 Crestal

1.85 (0.91)

1.72 (0.89)

1.98 (0.94)

0.332

 Buccal

2.20 (0.91)

2.35 (0.93)

2.05 (0.88)

0.271

 Lingual

1.97 (1.05)

2.30 (1.21)

1.61 (0.72)

0.026

 Crestal

2.32 (0.86)

2.33 (0.94)

2.31 (0.79)

0.941

Height of the anterior mandible (mm)^a

27.7 (3.6)

28.3 (3.5)

27.2 (3.6)

0.278

 II

2 (4.3)

2 (8.7)

0 (0)

0.275

 III

40 (85.1)

18 (78.3)

22 (91.7)

 IV

5 (10.6)

3 (13.0)

2 (8.3)