Anatomical Assessment Of Mandibular Lingual Foramina Observation By Cone Beam Computed Tomography

Objective The present study aimed to assess the anatomical positions and structures of the mandibular lingual foramina and lingual canals by cone beam computed tomography(CBCT), as well to compare the identification of the both anatomical landmarks on two different oral radiographs---CBCT and panoramic radiograph(OPG). Then based on the statistics data and observation results of the prevalence, size, locations and properties of lingual foramina and canals, we can remind the oral surgeon dentists to avoid these intraoperative and postoperative complications in mandibular surgery.Materials and Methods The characteristics of the lingual foramina was investigated using CBCT and OPG images obtained from 33 patients, including 30 dentulous patients (13 male,17 female; the average age is 30.3) and 3 edentulous patients. All the patients were from Stomatology Hospital affiliated to Zhejiang University(Hangzhou, Zhejiang, China), from November,2009 to January,2010. After image processing and reconstruction, two professional dentists conducted the measurement and observation as follows:①Evaluate the image clarity of lingual foramina on mandibular midline area and lateral region, by rating them to three grades--invisible (0 points), visible but not clear (1 point), clear (2 points), on CBCT and OPG images, then compare them.②Measure the midline and lateral lingual foramina and canals by diameter of three dimensions, distance from upper and lower mandibular cortex, length of the canal, direction and angles of the canal; Describe the shape, structures and directions of the foramina and canals. All the data was analyzed by statistical package of SPSS 13.0 software.Results and Discussion Comparing the visibility of mandibular midline lingual foramina between CBCT and OPG images, no obvious differences were found. Comparing the clarity of midline lingual foramina, the visibility and clarity of lateral lingual foramina between CBCT and OPG images, high obvious differences were found, CBCT displayed much better. On the mandible CBCT images, midline foramina were observed more than one and mainly under spine. The foramina diameter was far more lager in adult group. Left lingual foramina were mainly observed above spine in adult group, while under spine in adolescent group. Right lingual foramina were mostly observed under spine with highly obvious differences. The distance from mandibular base of lateral lingual foramina in adolescents were much smaller than in adults. Midline lingual canals were observed in more than 90 percent of patients, mainly near the bottom of mandibular bone. The canal length was about 5～7mm, and the diameter was about 0.3～1.5mm. Lateral lingual canals were mostly observed near the bottom, and the existence rate was about 50%. No obvious differences were found in the left lingual canal spine locations while right lingual canals were mainly found under spine.Conclusion The visibility of mandibular lingual anatomical landmarks on CBCT is much better than OPG. The observations of CBCT can help clinicians to reduce the risk of intra-/post-operative sensitivity due to injury of the mandibular lingual foramina or canals. CBCT plays an important role in pre-surgical treatment planning, increasing clinician's certainty of the need of additional surgicalprocedures (bone grafting, sinus lifting, and others) in pre-surgical treatment stage.