[Measurement and analysis of the nasopalatine canal and its relative position by cone-beam computed tomography]

To evaluate dimensions of the nasopalatine canal and the relationship between the canal and the central incisors, and the canal and the crest, by using cone-beam computed tomography (CBCT).

This study included 129 CBCTs, and the sagittal slices were used to measure the lower diameter (Sda), median diameter (Sdb), and higher diameter (Sdc), for calculating the average sagittal diameter (Sd); the coronal slices through canals were used to measure the lower diameter (Hda), median diameter (Hdb), and higher diameter (Hdc) for calculating the average horizontal diameter (Hd), length (H); the sagittal slices were used to measure the buccal bone thickness off the canal (Bt), and the distance to the crest off the lowest point (At), the horizontal slices were used to measure the distance between the canal and the central incisors (Id). These subjects were divided into two groups by gender; and divided into three groups by ages: (1) ≤ 30 years old, (2) 31-50 years old, and (3) ≥ 51 years old. SPSS 17.0 statistical software was used for statistical analysis.

The overall Sd was (3.41 ±0.87) mm, the Hd was (5.16±0.93) mm, and the difference was statistically significant. The H was (14.29 ± 3.27) mm, the Bt was (7.49 ± 1.05) mm, the At was (8.25 ± 1.71) mm, and the Id was (2.71±0.89) mm. Of the male and female, the Sd were (3.64 ± 0.90) mm and (3.28 ± 0.82) mm, P=0.017; the Hd were (4.98 ± 0.89) mm and (5.27 ± 0.94) mm, P=0.081; the H were (15.47 ± .75) mm and (13.59 ± 3.32) mm, P=0.001; the Bt were (7.90 ± 0.96) mm and (7.25 ± 1.03) mm, P=0.001; the At were (7.41 ± 1.86) mm and (8.44 ± 1.90) mm, P=0.001; the Id were (2.71 ± 0.87) mm and (2.72 ± 0.91) mm, P=0.983. Among the groups, no statistically significant differences were detected of the Sd (P=0.325), of the Hd (P=0.636), of the H (P=0.292), and of the Bt (P=0.116); statistically significant differences were detected of the At (P=0.010), and of the Id (P<0.001).

The nasopalatine canal anatomy is highly variable. Gender is related to the nasopalatine canal length, Bt width, and At distance. While age was related to At, and Id, but no effect on nasopalatine dimensions. The CBCT is a useful device for studying the nasopalatine canal in three dimensions, prior to dental implant placement.