The nasopalatine canal revisited using 2D and 3D CT imaging

OBJECTIVES: To assess the location, morphology and dimensions of the nasopalatine canal on two-dimensional and three-dimensional (2D and 3D) CT images. METHODS: Material included 34 spiral CT scans for pre-operative planning of implant placement in the maxilla. Scanning was performed using a standard exposure and patient positioning protocol. 2D and 3D spiral CT images were carefully examined for the location, morphology and dimensions of the nasopalatine canal by two independent observers. A comparison was made between 2D observations and a 2D/3D combined observation strategy (paired t-tests). RESULTS: The nasopalatine canal typically appeared as a canal with a mean (standard deviation (SD)) length of 8.1 (3.4) mm. Its palatal opening is the incisive foramen with a mean (SD) inner Ø of 4.6 (1.8) mm. At the level of the nasal floor often 2 (Y-canal morphology), but sometimes 3 or 4 openings could be observed. In particular cases, the canal showed up as a cylinder with only one nasal opening. The average (SD) maximum width of the nasopalatine canal structure at the level of the nasal floor was 4.9 (1.2) mm. The buccopalatal width of the jaw, anterior to the canal was 7.4 (2.6) mm. Interpretation of canal morphology was significantly different when comparing 2D image observation with a 2D/3D combined observation strategy. However, dimensional measurements of the canal were not significantly different for a 2D and a combined 2D/3D approach. CONCLUSIONS: The nasopalatine canal may show important anatomical variations, both with regard to morphology and dimensions. To avoid any potential complications during surgical procedures such as implant placement, a careful pre-operative observation is required. Cross-sectional imaging may be advocated to determine canal morphology and dimensions and to assess anterior bone width for potential implant placement buccally to the canal.