Histological and CT scan characterisation of the nasopalatine canal

Methods: The study included 120 upper jaw spirals CT scans, taken from patients (16-73 years old; 65 females) for preoperative planning purposes of implant placement in the incisor region. The morphological variations were observed by 3 observers. Furthermore, linear measurements were performed using a digital sliding calliper to describe the canal characteristics. Besides these radiographic observations, the microanatomical canal characteristics and the canal content were further studied. Two human cadaver specimens were imaged using a 9.4 Tesla MRI unit. Afterwards, these specimens were decalcified, embedded in paraffine and serially sectioned (7 µm) for further examination using routine light microscopy to inspect the incisive canal region and its content.

Results: On spiral CT scans, nasopalatine canals were running into 1-4 canals from the palate to the nose level. One canal was detected in 53 cases (44%), in 47 cases two canals were noted (39%), in another 20 cases, 3 or 4 canals were noted (17%). The mean (SD) diameters of the canal structures was 3.58 (SD±1.0) mm respectively with an average length of 9.89 (SD±2.59) mm. The canal was located on average 77.44° (SD±8.89°) to the horizontal plate. The slope between canal and vertical slice of the palate bone was 4.93° on average (SD±5.38°). The slope between canal and incisor tooth was 7.90° on average (SD±5.72°).

Conclusions: The present results imply that in order to keep and protect the functions of the neurovascularisation in the canal, surgeons should carefully inspect this region pre-operatively and avoid damaging the neurovascular instead of potential removal.