DOI:

10.37988/1811-153X_2025_3_160

Putative measurement for alarming orthopantomogram relationship between mandibular third molar and inferior alveolar canal proved by CBCT: A cross-sectional study

Downloads

Authors

  • A.I. Alnuaimy 1, DDS, MSc, lecturer of the Department of Oral and Maxillofacial Radiology
    ORCID: 0000-0002-7530-0759
  • S.J. Mahmood 2, DDS, MSc, assistant professor of the Oral medicine Department
    ORCID: 0000-0002-7900-3698
  • F. Alhamdani 3, DDS, MSc, PhD, full professor of the Oral and maxillofacial surgery and oral diagnostic Department
    ORCID: 0000-0002-4899-824X
  • M.K. Mohammed Ali 4, DDS, MSc specialist at the Oral and Maxillofacial Radiology Department
    ORCID: 0009-0001-5273-2217
  • R.M. Al-Bayati 4, DDS, MSc, specialist at the Oral and Maxillofacial Radiology Department
    ORCID: 0000-0002-5822-7422
  • 1 Al-Iraqia University, 10071, Baghdad, Iraq
  • 2 Mustansiriyah University, 14022, Baghdad, Iraq
  • 3 Ibn Sina University of Medical and Pharmaceutical Science, 10064, Baghdad, Iraq
  • 4 Al-Sadir Specialized Dental Center, 10059, Baghdad, Iraq

Abstract

Cone-beam computed tomography (CBCT) provides three-dimensional assessment of the relationship between mandibular third molars (MTMs) and the inferior alveolar canal (IAC). It is crucial for reducing post-operative surgical complications. However, it might not be always available. However, orthopantomograms (OPG) remain the first-line investigation and help determine the need for further CBCT evaluation. Objective — to determine possible alarming OPG radiographic features in terms of the relationship between imparted lower third molar and IAC.
Materials and methods.
Total 85 patients with 113 mandibular third molars were evaluated. OPG images were examined according to Rood and Shehab’s criteria. Root deflection, root darkening, and interruption of the white line were identified. Then, all cases underwent further examination with CBCT to determine the spatial relationship between MTMs and IAC and measure the distance between them. The results were classified into safe (≥2 mm) and high-risk (<2 mm) groups.
Results.
According to OPG results, root deflection was the most common radiographic sign (53.1%), followed by root darkening (38%) and interruption of the white line (8.8%). The IAC was most frequently positioned buccally (49.5%), followed by inferiorly (31.8%) and lingually (18.5%) in CBCT imaging. A strong connection was noticed between the OPG radiographic signs and CBCT-measured distances. Of the 113 MTMs, 59.3% were categorized as high risk (<2 mm), comprising 47.8% root deflection. The root darkening was more frequently correlated with the safe distance group (33.6%).
Conclusion.
Despite that OPG findings can predict the nature of the relationship between IAC and MTM, it is not useful in assessing the distance. However, it can be suggested that root deflection in the OPG radiograph might carry more nerve injury risk than other radiographic findings. This is based on the fact that distance of ≤2 mm between the MTM and the IAC would increase the risk of nerve injury.

Key words:

mandibular third molars, inferior alveolar nerve, orthopantomogram, OPG, cone-beam computed tomography, CBCT

For Citation

[1]
Alnuaimy A.I., Mahmood S.J., Alhamdani F., Mohammed Ali M.K., Al-Bayati R.M. Putative measurement for alarming orthopantomogram relationship between mandibular third molar and inferior alveolar canal proved by CBCT: A cross-sectional study. Clinical Dentistry (Russia).  2025; 28 (3): 160—166. DOI: 10.37988/1811-153X_2025_3_160

References

  1. Sánchez-Jorge M.I., Cortés-Bretón-Brinkmann J., Acevedo-Ocaña R., Quispe-López N., Falahat F., Martín-Granizo R. Perceived surgical difficulty of mandibular third molar extraction. A comparative cross-sectional study of dentists with postgraduate qualification in oral surgery and maxillofacial surgeons in a Spanish subpopulation. Med Oral Patol Oral Cir Bucal. 2024; 29 (2): e263—e272. PMID: 38288853
  2. Shembesh H. Surgical extraction of mandibular third molars: Risk assessment and predictable complexity. Khalij-Libya Journal of Dental and Medical Research. 2024; 8 (1): 87—95. DOI: 10.47705/kjdmr.2481013
  3. Bui C.H., Seldin E.B., Dodson T.B. Types, frequencies, and risk factors for complications after third molar extraction. J Oral Maxillofac Surg. 2003; 61 (12): 1379—89. PMID: 14663801
  4. Susarla S.M., Blaeser B.F., Magalnick D. Third molar surgery and associated complications. Oral Maxillofac Surg Clin North Am. 2003; 15 (2): 177—86. PMID: 18088673
  5. Li Y., Ling Z., Zhang H., Xie H., Zhang P., Jiang H., Fu Y. Association of the inferior alveolar nerve position and nerve injury: A systematic review and meta-analysis. Healthcare (Basel). 2022; 10 (9): 1782. PMID: 36141394
  6. Blondeau F., Daniel N.G. Extraction of impacted mandibular third molars: postoperative complications and their risk factors. J Can Dent Assoc. 2007; 73 (4): 325. PMID: 17484797
  7. Valmaseda-Castellón E., Berini-Aytés L., Gay-Escoda C. Inferior alveolar nerve damage after lower third molar surgical extraction: a prospective study of 1117 surgical extractions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2001; 92 (4): 377—83. PMID: 11598570
  8. Nakamori K., Fujiwara K., Miyazaki A., Tomihara K., Tsuji M., Nakai M., Michifuri Y., Suzuki R., Komai K., Shimanishi M., Hiratsuka H. Clinical assessment of the relationship between the third molar and the inferior alveolar canal using panoramic images and computed tomography. J Oral Maxillofac Surg. 2008; 66 (11): 2308—13. PMID: 18940497
  9. Haug R.H., Perrott D.H., Gonzalez M.L., Talwar R.M. The American Association of Oral and Maxillofacial Surgeons age-related third molar study. J Oral Maxillofac Surg. 2005; 63 (8): 1106—14. PMID: 16094577
  10. Nakagawa Y., Ishii H., Nomura Y., Watanabe N.Y., Hoshiba D., Kobayashi K., Ishibashi K. Third molar position: reliability of panoramic radiography. J Oral Maxillofac Surg. 2007; 65 (7): 1303—8. PMID: 17577493
  11. Susarla S.M., Dodson T.B. Preoperative computed tomography imaging in the management of impacted mandibular third molars. J Oral Maxillofac Surg. 2007; 65 (1): 83—8. PMID: 17174769
  12. Ohman A., Kivijärvi K., Blombäck U., Flygare L. Pre-operative radiographic evaluation of lower third molars with computed tomography. Dentomaxillofac Radiol. 2006; 35 (1): 30—5. PMID: 16421261
  13. Al Ali S., Jaber M. Correlation of panoramic high-risk markers with the cone beam CT findings in the preoperative assessment of the mandibular third molars. J Dent Sci. 2020; 15 (1): 75—83. PMID: 32257003
  14. Huang C.K., Lui M.T., Cheng D.H. Use of panoramic radiography to predict postsurgical sensory impairment following extraction of impacted mandibular third molars. J Chin Med Assoc. 2015; 78 (10): 617—22. PMID: 26041067
  15. Hasegawa T., Ri S., Shigeta T., Akashi M., Imai Y., Kakei Y., Shibuya Y., Komori T. Risk factors associated with inferior alveolar nerve injury after extraction of the mandibular third molar—a comparative study of preoperative images by panoramic radiography and computed tomography. Int J Oral Maxillofac Surg. 2013; 42 (7): 843—51. PMID: 23499150
  16. Nakayama K., Nonoyama M., Takaki Y., Kagawa T., Yuasa K., Izumi K., Ozeki S., Ikebe T. Assessment of the relationship between impacted mandibular third molars and inferior alveolar nerve with dental 3-dimensional computed tomography. J Oral Maxillofac Surg. 2009; 67 (12): 2587—91. PMID: 19925976
  17. Rood J.P., Shehab B.A. The radiological prediction of inferior alveolar nerve injury during third molar surgery. Br J Oral Maxillofac Surg. 1990; 28 (1): 20—5. PMID: 2322523
  18. Pinto A.C., Francisco H., Marques D., Martins J.N.R., Caramês J. Worldwide prevalence and demographic predictors of impacted third molars — Systematic review with meta-analysis. J Clin Med. 2024; 13 (24): 7533. PMID: 39768456
  19. Adeola O., Fatusi O., Njokanma A., Adejobi A. Impacted mandibular third molar prevalence and patterns in a Nigerian Teaching Hospital: A 5-year retrospective study. BioMed. 2023; 4: 507—515. DOI: 10.3390/biomed3040040
  20. Monaco G., Montevecchi M., Bonetti G.A., Gatto M.R., Checchi L. Reliability of panoramic radiography in evaluating the topographic relationship between the mandibular canal and impacted third molars. J Am Dent Assoc. 2004; 135 (3): 312—8. PMID: 15058618
  21. Kim H.J., Jo Y.J., Choi J.S., Kim H.J., Kim J., Moon S.Y. Anatomical risk factors of inferior alveolar nerve injury association with surgical extraction of mandibular third molar in Korean population. Applied Sciences (Switzerland). 2021; 2: 816. DOI: 10.3390/app11020816
  22. Palma-Carrió C., García-Mira B., Larrazabal-Morón C., Peñarrocha-Diago M. Radiographic signs associated with inferior alveolar nerve damage following lower third molar extraction. Med Oral Patol Oral Cir Bucal. 2010; 15 (6): e886—90. PMID: 20526245
  23. Sedaghatfar M., August M.A., Dodson T.B. Panoramic radiographic findings as predictors of inferior alveolar nerve exposure following third molar extraction. J Oral Maxillofac Surg. 2005; 63 (1): 3—7. PMID: 15635549
  24. Umar G., Bryant C., Obisesan O., Rood J.P. Correlation of the radiological predictive factors of inferior alveolar nerve injury with cone beam computed tomography findings. Oral Surgery. 2010; 3: 72—82. DOI: 10.1111/j.1752—248X.2010.01088.x
  25. Safaee A., Mirbeigi S., Ezoddini F., Khojastepour L., Navab-Azam A. Buccolingual course of the inferior alveolar canal in different mental foramen locations: A cone beam computed tomography study of an Iranian population. Int J Appl Basic Med Res. 2016; 6 (4): 262—266. PMID: 27857894
  26. Matzen L.H., Wenzel A. Efficacy of CBCT for assessment of impacted mandibular third molars: a review — based on a hierarchical model of evidence. Dentomaxillofac Radiol. 2015; 44 (1): 20140189. PMID: 25135317
  27. Tofangchiha M., Koushaei S., Mortazavi M., Souri Z., Alizadeh A., Patini R. Positive predictive value of panoramic radiography for assessment of the relationship of impacted mandibular third molars with the mandibular canal based on cone-beam computed tomography: A cross-sectional study. Diagnostics (Basel). 2021; 11 (9): 1578. PMID: 34573920
  28. Wang W.Q., Chen M.Y., Huang H.L., Fuh L.J., Tsai M.T., Hsu J.T. New quantitative classification of the anatomical relationship between impacted third molars and the inferior alveolar nerve. BMC Med Imaging. 2015; 15: 59. PMID: 26643322
  29. Wang D., Lin T., Wang Y., Sun C., Yang L., Jiang H., Cheng J. Radiographic features of anatomic relationship between impacted third molar and inferior alveolar canal on coronal CBCT images: risk factors for nerve injury after tooth extraction. Arch Med Sci. 2018; 14 (3): 532—540. PMID: 29765439

Downloads

Received

February 5, 2025

Accepted

April 8, 2025

Published on

September 21, 2025