The retromolar canals and foramina: radiographic observation and application to oral surgery
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The retromolar canal (RMC) and foramen (RMF) are anatomic variants in the retromolar area of the mandible. The purpose of this study was to clarify the relationship between the RMC and RMF and related complications, and to reveal how the RMC could impact the mandibular anatomy using cone-beam computed tomography (CBCT) and panoramic images (PAN).
Materials and methods
CBCT and PAN images of 50 patients were retrospectively analyzed to investigate the morphology of the RMC and RMF, and their impact on impacted third molar surgery and orthognathic surgery.
In PAN images, neither the RMC nor RMF was detected. In CBCT images, the RMCs were detected in 26% (13/50) of the patients. A double RMC was detected on one side of one patient. The diameter of the RMC ranged from 0.8 to 2.9 mm (mean; 1.5 ± 0.6 mm), and the RMF ranged from 0.6 to 2.3 mm (mean; 1.1 ± 0.5 mm). No patients experienced unexpected bleeding. Unilateral postoperative hypoesthesia of the buccal gingiva in the molar region was reported in 6.7% of patients with the RMC.
Hypoesthesia of the buccal gingiva in the lower molar region may be the main complication when the RMC is damaged.
KeywordsCone-beam computed tomography Anatomic variation Mandible Oral surgery Retromolar canal Retromolar foramen
The authors wish to express their gratitude to the radiological technician Reiji Katayama in the Diagnostic Imaging Center, Kurume University Hospital.
SK: protocol/project development, data collection or management, data analysis, and manuscript writing/editing, final approval/guarantor of manuscript. JI: protocol/project development, data analysis, manuscript writing/editing, and final approval/guarantor of manuscript. KN: data collection or management, data analysis, and final approval/guarantor of manuscript. KH: data collection or management, data analysis, and final approval/guarantor of manuscript. MN: protocol/project development, manuscript writing/editing, andfinal approval/guarantor of manuscript. JK: protocol/project development, data analysis, manuscript writing/editing, and final approval/guarantor of manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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