Clinical Implications of the Localization and Morphological Variability of the Mental Foramen—A Systematic Review
Abstract
1. Introduction
2. Materials and Methods
2.1. Search Strategy and Data Extraction
2.2. Eligibility Criteria
2.3. Risk of Bias and Data Synthesis
3. Results
4. Discussion
4.1. Position of the Mental Foramen in Relation to the Superior and Inferior Border of the Mandible
4.2. Position of the Mental Foramen in Relation to Tooth Groups
4.3. Vertical Position of the Mental Foramen
4.4. Shape of the Mental Foramen
4.5. Presence of Accessory Mental Foramina, Absence of the Mental Foramen and Its Rare Variation
4.6. Limitations
4.7. Clinical Implications
4.8. Future Research Directions
5. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
- Thomaidi, Z.M.; Tsatsarelis, C.; Papadopoulos, V. Accessory Mental Foramina in Dry Mandibles: An Observational Study Along with Systematic Review and Meta-Analysis. Dent. J. 2025, 13, 94. [Google Scholar] [CrossRef] [Scilit]
- Mahmoudinezhad, S.S.; AryanKia, A.; Shooshtari, S.S.; Moradi, K. The Effect of Mandibular Angulation on Preoperative Assessment of Dental Implant Insertion at Premolar Region: CBCT Study. BioMed Res. Int. 2022, 2022, 7879239. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- AlQahtani, N.A. Assessment of the position and level of mental nerve for placement of implants using cone-beam computed tomography & panoramic radiograph in the Saudi population. Saudi Dent. J. 2022, 34, 315–320. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Al Dalalah, A.; Kana’an, N.; Ersheidat, A.; Momani, M.; Altantawi, H. Evaluating the Anterior Loop of the Mental Nerve Using Cone Beam CT Scans in the Jordanian Population. Cureus 2024, 16, e58519. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Page, M.J.; McKenzie, J.E.; Bossuyt, P.M.; Boutron, I.; Hoffmann, T.C.; Mulrow, C.D.; Shamseer, L.; Tetzlaff, J.M.; Akl, E.A.; Brennan, S.E.; et al. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ 2021, 372, n71. [Google Scholar] [CrossRef] [Scilit]
- Abu-Ta’a, M.F.; Qubain, K.J.; Beshtawi, K.R. The mental foramen, anatomical parameters through a radiographic approach to aid in dental implantology: A retrospective analysis in a sample of a Palestinian population. Heliyon 2023, 9, e13886. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Mallahi, E.; Abesi, F.; Rajaei-Rad, F.; Gholinia, H. Anatomical characteristics of mental foramen and canal: A cone-beam computed tomography analysis. J. Clin. Exp. Dent. 2024, 16, 1004–1011. [Google Scholar] [CrossRef] [PubMed] [PubMed Central]
- Zmyslowska-Polakowska, E.; Radwanski, M.; Ledzion, S.; Leski, M.; Zmyslowska, A.; Lukomska-Szymanska, M. Evaluation of Size and Location of a Mental Foramen in the Polish Population Using Cone-Beam Computed Tomography. BioMed Res. Int. 2019, 2019, 1659476. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Sheth, K.; Banga, K.S.; Pawar, A.M.; Gutmann, J.L.; Kim, H.C. Shape and anatomical relationship of the mental foramen to the mandibular premolars in an Indian sub-population: A retrospective CBCT analysis. Restor. Dent. Endod. 2021, 47, e1. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Srivastava, S.; Sethi, K.K.; Sinha, A.; Srivastava, A.; Mishra, A.; Khan, N.; Pandey, S.; Sethi, K. Assessing the Prevalence and Length of the Anterior Loop of Inferior Alveolar Nerve and the Position and Dimension of Mental Foramen Using Cone Beam Computed Tomography. Cureus 2024, 16, e68535. [Google Scholar] [CrossRef] [Scilit]
- Barbosa, D.A.F.; Maferano, E.F.E.; Teixeira, R.C.; Kurita, L.M.; Pimenta, A.V.M.; Silva, P.G.B.; Chaves, F.N.; Gurgel, M.L.; Costa, F.W.G. Epidemiological and Radiomorphometric Aspects of the Accessory Mental Foramen in Brazilian Individuals: An Analysis by Cone Beam Computed Tomography. J. Clin. Exp. Dent. 2024, 16, 1379–1385. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Guzmán, J.; Abarca, J.; Navarro, P.; Garay, I.; Arnabat-Domínguez, J.; Betancourt, P. Morphometric Analysis of the Mandibular Canal and Its Anatomical Variants in a Chilean Subpopulation: Cone Beam Computed Tomography Study. Diagnostics 2024, 14, 1914. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Reda, R.; Zanza, A.; Bhandi, S.; Biase, A.; Testarelli, L.; Miccoli, G. Surgical-anatomical evaluation of mandibular premolars by CBCT among the Italian population. Dent. Med. Probl. 2022, 59, 209–216. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Gherghiţă, O.R.; Csiki, I.E.; Bordea, E.N.; Pellegrini, A.; Cismaş, S.C.; Motaş, N.; Nimigean, V.R.; Nimigean, V. Morphometric study for determining the anteroposterior position of the mental foramen in dentate human subjects. Rom. J. Morphol. Embryol. 2021, 62, 517–523. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Shashidhar, K.; Sridevi, N.S. Anthropometric analysis of mental foramen in dry human mandibles in Karnataka. Natl. J. Clin. Anat. 2019, 8, 148–152. [Google Scholar] [CrossRef] [Scilit]
- Mohebiniya, M.; Kamani, M. Multiple Mental Foramina: A Rare Anatomical Variation Detected by Cone-Beam Computed Tomography (CBCT). Cureus 2024, 16, e63524. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Lauhr, G.; Coutant, J.C.; Normand, E.; Laurenjoye, M.; Ella, B. Bilateral absence of mental foramen in a living human subject. Surg. Radiol. Anat. 2015, 37, 403–405. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Haffaf, R.A.; Younes, M.M.; Shqera, A.Y.; Assad, M.; Hasan, A.K. Assessment of Mental Foramen Characteristics in Syrian Population Using Cone Beam Computed Tomography: A Pilot Study. Cureus 2024, 16, e58549. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Singh, P.; Adhikari, B.; Koju, S.; Gupta, S.; Pradhan, M.; Gurung, D.; Joshi, U. Mean Distance of Mental Foramen from Inferior Border of Mandible among Patients Visiting the Outpatient Dental Department in a Tertiary Care Centre. JNMA J. Nepal Med. Assoc. 2023, 61, 787–790. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Karabıyık, Z.; Kıranatlı, M. A Rare Anatomical Finding: Bilateral Accessory Mental Foramen. Case Rep. Dent. 2021, 2021, 6020515. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Tiwari, N. Left Accessory Mental Foramen in Dry Mandibles in Department of Anatomy in a Medical College: A Descriptive Cross-sectional Study. JNMA J. Nepal Med. Assoc. 2022, 60, 805–807. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Yovchev, D.; Mihaylova, H.; Kirilova, J.; Deliverska, E. Rare anatomic variations: Agenesis of left mental foramen coexisting with two right mental foramina. J. IMAB 2024, 30, 5645–5647. [Google Scholar] [CrossRef] [Scilit]
- Alam, B.F.; Yusof, A.; Shah, S.A.; Abdullah, J.Y.; Nawi, M.A.A. Morphometric Analysis of the Dimension and Distance to Anatomical Structures From the Mental Foramen Using Cone Beam Computed Tomography. Cureus 2024, 16, e71496. [Google Scholar] [CrossRef] [Scilit]
- Ahmed, A.A.; Ahmed, R.M.; Jamleh, A.; Spagnuolo, G. Morphometric Analysis of the Mandibular Canal, Anterior Loop, and Mental Foramen: A Cone-Beam Computed Tomography Evaluation. Int. J. Environ. Res. Public Health 2021, 18, 3365. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Le, L.N.; Do, T.T.; Truong, L.T.; Truong, M.H.; Ngoc, D.K.H.; Nguyen, L.M.; Nguyen, L., Jr. Cone Beam CT Assessment of Mandibular Foramen and Mental Foramen Positions as Essential Anatomical Landmarks: A Retrospective Study in Vietnam. Cureus 2024, 16, e59337. [Google Scholar] [CrossRef] [Scilit]
- Taschieri, S.; Vitelli, C.; Albano, D.; Sconfienza, L.; Del Fabbro, M.; Francetti, L.; Parrini, M.; Corbella, S. Evaluation of mental foramen and inferior alveolar nerve canal and its relationship to adjacent anatomical landmarks using cone-beam computer tomography. J. Biol. Regul. Homeost. Agents 2021, 35, 107–115. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Dall’Azen, G.C.; Morosolli, A.R.C.; Hartmann, R.C.; Rockenbach, M.I.B. Measurement of the mandibular canal and mandibular incisive canal using cone beam tomography in adults from South Brazil. J. Oral Sci. 2024, 66, 169–175. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Alazemi, A.; Muhairi, E.A.; Alharbi, N.; Abdunabi, F.; Mashyakhy, M.; Chaudhry, J.; Moharamzadeh, K.; Abed, R.E.; Jamal, M. Evaluation of Mental Foramen and Mandibular Canal Course and Location in an Emirati Subpopulation. Int. Dent. J. 2024, 74, 1142–1150. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Ghandourah, A.O.; Badaoud, M.B.; Dahlawi, A.; Alghamdi, A.; Alhazmi, F.; Sembawa, S.N.; Demyati, A.K. A radiographic analysis of the location of the mental foramen. Saudi Dent. J. 2023, 35, 354–358. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Dos Santos Oliveira, R.; Rodrigues Coutinho, M.; Kühl Panzarella, F. Morphometric Analysis of the Mental Foramen Using Cone-Beam Computed Tomography. Int. J. Dent. 2018, 2018, 4571895. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Subramanian, B.; Anthony, S.N.; Mubbunu, L.; Hachombwa, C.; Mlawa, M.S.; Majambo, M.M.; Sasi, R.M. Anthropometrics Analysis of Mental Foramen and Accessory Mental Foramen in Zambian Adult Human Mandibles. Sci. World J. 2019, 2019, 9093474. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Aljarbou, F.; Riyahi, A.M.; Altamimi, A.; Alabdulsalam, A.; Jabhan, N.; Aldosimani, M.; Alamri, H.M. Anatomy of the accessory mental foramen in a Saudi subpopulation: A multicenter CBCT study. Saudi Dent. J. 2021, 33, 1012–1017. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Beshtawi, K.R.; Qirresh, E. A rare case of an anatomical variant of nonexistent mental foramen. Radiol. Case Rep. 2024, 20, 1082–1086. [Google Scholar] [CrossRef] [Scilit] [PubMed] [PubMed Central]
- Borghesi, A.; Pezzotti, S.; Nocivelli, G.; Maroldi, R. Five mental foramina in the same mandible: CBCT findings of an unusual anatomical variant. Surg. Radiol. Anat. 2018, 40, 635–640. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Predoiu, M.; Rusu, M.C.; Chiriţă, A.L. A rare anatomic variation: Triple mental foramina. Morphologie 2019, 103, 110–115. [Google Scholar] [CrossRef] [Scilit] [PubMed]
- Tallada, A.K.; Ahmed, J.; Sujir, N.; Shenoy, N.; Pawar, S.M.; Muralidharan, A.; Mallya, S. Accessory lingual mental foramen: A case report of a rare anatomic variation. Oral Radiol. 2024, 40, 410–414. [Google Scholar] [CrossRef] [Scilit] [PubMed]



| Study ID | Country/ Population | Sample Size (Mandibles/Patients) | Method | MF Horizontal Position | MF Vertical Position | Variants Reported | Key Finding |
|---|---|---|---|---|---|---|---|
| Abu-Ta’a et al., 2023 [6] | Palestine | 106 cases | CBCT | III (PM1–PM2) 49% | Below apex 48% | Accessory MF rare | Predominant location of MF between the first and second premolars, observed in nearly half of the studied cases |
| Mallahi et al., 2024 [7] | Iran | 355 cases | CBCT | II–III | Below apex | Anterior loop | MF most commonly located inferiorly, with frequent identification of an anterior loop in this population |
| Zmysłowska- Polakowska et al., 2019 [8] | Poland | 201 cases | CBCT | III 56% | Below apex 54% | — | Type III horizontal position was the most frequent pattern in the Polish population, exceeding half of the examined cases |
| Sheth et al., 2021 [9] | India | 475 cases | CBCT | III 71% | Below apex 66% | — | High predominance of type III horizontal position in the Indian population, observed in more than two-thirds of cases |
| Srivastava et al., 2024 [10] | India | 250 cases | CBCT | PM2 62% | Below apex 62% | Anterior loop (long) | Anterior loop length reached up to 6–7 mm, representing a clinically relevant extension of the mental nerve |
| Barbosa et al., 2024 [11] | Brazil | 250 cases | CBCT | III 58% | Below apex 58% | Accessory MF | Accessory mental foramina were detected in a notable proportion of cases, indicating a non-negligible prevalence in this population |
| Guzmán et al., 2024 [12] | Chile | 342 cases | CBCT | PM2 62% | Below apex 62% | — | Alignment of the MF with the second premolar represented the dominant horizontal position in this Chilean subpopulation |
| Reda et al., 2022 [13] | Italy | 492 cases | CBCT | III 92% | Below apex 92% | — | Symmetrical positioning of MF was consistently observed on both sides of the mandible |
| Gherghiță et al., 2021 [14] | Romania | 40 cases | CBCT | Left: PM2/41% Right: PM1–PM2 56% | Below apex | — | Distinct side-related differences in horizontal MF position were identified between the left and right mandible |
| Shashidhar et al., 2019 [15] | India | 180 cases | Anthropometry | IV 88% | Below apex | — | The mental foramen was most frequently positioned posterior to the second premolar, with no side-related differences observed |
| Mohebiniya et al., 2024 [16] (case report) | Iran | 1 case | CBCT | Variable | — | Multiple MF | Rare anatomical variation characterized by bilateral duplication of MF identified on CBCT imaging |
| Lauhr et al., 2015 [17] (case report) | Caucasus | 1 case | CBCT | — | — | — | Extremely rare anatomical finding of bilateral absence of MF documented in a living subject |
| Parameter | Reported Range | Reported Mean ± SD (Where Available) | Studies Reporting Mean (n) | Notes |
|---|---|---|---|---|
| Distance MF–Inferior Border | 10–16 mm | 11.83 ± 1.83 mm, 11.54 mm; 13.52 mm | 3 | Often greater in older patients due to alveolar bone resorption |
| Distance MF–Alveolar Crest | 7–12 mm | not reported | 0 | Greatly reduced in edentulous mandibles |
| Horizontal position | Mostly position III (PM1–PM2) | not reported | 0 | With exceptions in Sudanese, Indian, Chilean populations |
| Vertical position | Predominantly below root apices | not reported | 0 | Type III (Zmysłowska-Polakowska) |
| MF shape | Oval > Round > Irregular | not reported | 0 | Shape correlated with sex in some populations |
| Accessory MF | 1–12% | not reported | 0 | Most commonly located distally to main MF |
| Anterior loop length | 1–7.5 mm | Right: 6.43 ± 2.17 mm; Left: 6.56 ± 1.81 mm | 1 | Must be evaluated preoperatively |
| Study | I | II | III | IV | V | VI |
|---|---|---|---|---|---|---|
| Abu-Ta’a et al., 2023 [6] | NR | NR | 49 | NR | 6/5 | NR |
| Mallahi et al., 2024 [7] | NR | NR | NR | NR | NR | NR |
| Zmysłowska-Polakowska et al., 2019 [8] (right/left site) | 0/0 | 4.5/5.0 | 58.7/55.4 | 34.4/31.3 | 4.5/7.9 | 0/0 |
| Sheth et al., 2021 [9] (right/left site) | 0/0 | 6/10 | 26/14 | 62/71 | 6/5 | 0/0 |
| Srivastava et al., 2024 [10] | 0 | 1.0 | 27.2 | 61.6 | 9.8 | 0.4 |
| Barbosa et al., 2024 [11] | NR | NR | NR | NR | NR | NR |
| Guzmán et al., 2024 [12] | NR | 9.5 | 62.0 | 25.5 | 3.0 | NR |
| Reda et al., 2022 [13] | NR | 8 | 92 | NR | NR | NR |
| Gherghiță et al., 2021 [14] | NR | NR | 56 | 41 | NR | NR |
| Shashidhar et al., 2019 [15] | NR | NR | NR | 88 | NR | NR |
| Median (%) | 0.0 | 8.8 | 56.0 | 51.3 | 6.4 | 0.4 |
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Krzykawska-Krupska, M.; Pach, J.; Regulski, P.; Tomczyk, J.; Strużycka, I.; Szopiński, K.; Osipowicz, K.; Pogorzelska, A. Clinical Implications of the Localization and Morphological Variability of the Mental Foramen—A Systematic Review. Diagnostics 2026, 16, 779. https://doi.org/10.3390/diagnostics16050779
Krzykawska-Krupska M, Pach J, Regulski P, Tomczyk J, Strużycka I, Szopiński K, Osipowicz K, Pogorzelska A. Clinical Implications of the Localization and Morphological Variability of the Mental Foramen—A Systematic Review. Diagnostics. 2026; 16(5):779. https://doi.org/10.3390/diagnostics16050779
Chicago/Turabian StyleKrzykawska-Krupska, Mariola, Janusz Pach, Piotr Regulski, Jacek Tomczyk, Izabela Strużycka, Kazimierz Szopiński, Katarzyna Osipowicz, and Anna Pogorzelska. 2026. "Clinical Implications of the Localization and Morphological Variability of the Mental Foramen—A Systematic Review" Diagnostics 16, no. 5: 779. https://doi.org/10.3390/diagnostics16050779
APA StyleKrzykawska-Krupska, M., Pach, J., Regulski, P., Tomczyk, J., Strużycka, I., Szopiński, K., Osipowicz, K., & Pogorzelska, A. (2026). Clinical Implications of the Localization and Morphological Variability of the Mental Foramen—A Systematic Review. Diagnostics, 16(5), 779. https://doi.org/10.3390/diagnostics16050779

