• Atiphan Pimkhaokham D.D.S., Ph.D., Diplomate, Thai Board of Oral and Maxillofacial Surgery
• Keskanya Subbalekha D.D.S., Ph.D., Diplomate, Thai Board of Oral and Maxillofacial Surgery
• Natthaporn Pravitharangkul
• Siripim Sawetchaikul

The objective of this study was to investigate the prevalence and location of retromolar
canal in Thai patients in a private radiographic center in Bangkok using the cone beam computed
tomograph (CBCT) images which including the retromolar region. The images were collected from
2010-2011. The retromolar canal was investigated using the One Volume Viewer software.
The distances between retromolar foramen and mandibular canal, buccal bone plate, lingual bone plate
and the distal surface of the second molar were measured and the averages were calculated.
The relationships between the prevalence of retromolar canal and gender and sides were analyzed by
Fisherûs exact test. Sixty-four images were provided the detail of retromolar region. The retromolar
canal was found in 8 images (12.5%). The average distances between retromolar foramen and
mandibular canal, buccal bone plate, and lingual bone plate were 12.07, 7.04 and 5.14 mm,
respectively. In addition, the average distances between retromolar foramen and the distal surface of
the second molar was 15.90 mm. There was no significant difference between the prevalence
of retromolar canal and both gender and side of mandible (p > 0.05). In conclusion, although
the prevalence of patients with retromolar canals detected by CBCT in a radiographic center in
Bangkok is quite low, it is necessary to be aware of this variation when performing surgery.

(CU Dent J. 2015;38:105-116)