Table 1 Distribution of CS with different diameters in the maxilla anterior and the comparision of the four measurements and location between right and left sides (NCF:distance between CS and nasal cavity floor, BCM:distance between CS and buccal cortical bone margin, ACr:distance between CS and alveolar crest, CS ≥ 1 mm: diameter of CS measured at least 1 mm) 

Presence of CS < 1 mm, n(%)

 Absent

216 (72.2)

239 (80.2)

0.020^a

 Present

83 (27.8)

59 (19.8)

Diameter of CS ≥ 1 mm

 Mean ± SS

1.31 ± 0.19

1.29 ± 0.17

0.212^a

 Median (Min.-Max.)

1.26 (1.00–1.79)

1.26 (1.00–1.79)

Location, n(%)

 Intercentral

29 (9.9)

22 (7.6)

0.622^b

 Central Incisors

93(31.8)

71 (24.3)

 Central-Lateral Incisors

60 (20.6)

83 (28.5)

 Lateral Incisors

60 (20.6)

73 (25.1)

 Lateral Incisors-Canine

29 (9.9)

29 (10.0)

 Canine

21 (7.2)

13 (4.5)

ACs-NCF

 Mean ± SS

11.87 ± 3.61

11.81 ± 4.13

0.632^b

 Median (Min.-Max.)

12.01 (3.42–21.00)

11.91 (2.04–21.15)

ACs-BCM

 Mean ± SS

4.60 ± 1.69

4.73 ± 1.75

0.805^b

 Median (Min.-Max.)

4.81 (0.89–8.41)

4.83 (0.80–12.01)

ACs-ACr

 Mean ± SS

7.77 ± 3.24

7.93 ± 3.79

0.443^b

 Median (Min.-Max.)

7.22 (1.26–8.09)

7.38 (0.89–21.85)