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The retromolar canals and foramina: radiographic observation and application to oral surgery

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Abstract

Purpose

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.

Results

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.

Conclusions

Hypoesthesia of the buccal gingiva in the lower molar region may be the main complication when the RMC is damaged.

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Acknowledgements

The authors wish to express their gratitude to the radiological technician Reiji Katayama in the Diagnostic Imaging Center, Kurume University Hospital.

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Authors and Affiliations

  1. Dental and Oral Medical Center, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan

    Shogo Kikuta, Joe Iwanaga, Ken Nakamura, Kiyosato Hino, Moriyoshi Nakamura & Jingo Kusukawa

  2. Seattle Science Foundation, 550 17th Avenue, Suite 600, Seattle, WA, 98122, USA

    Joe Iwanaga

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  1. Shogo Kikuta
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  2. Joe Iwanaga
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  3. Ken Nakamura
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  4. Kiyosato Hino
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  5. Moriyoshi Nakamura
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  6. Jingo Kusukawa
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Contributions

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.

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Correspondence to Shogo Kikuta.

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The authors declare no conflict of interest.

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Kikuta, S., Iwanaga, J., Nakamura, K. et al. The retromolar canals and foramina: radiographic observation and application to oral surgery. Surg Radiol Anat 40, 647–652 (2018). https://doi.org/10.1007/s00276-018-2005-5

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  • DOI: https://doi.org/10.1007/s00276-018-2005-5

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