different anatomical variations related to the mental nerve and mental foramen in relation to dentistry and dental surgery planning including implantology.

1. Prepared By
Dr.Yamen Nouh
BDS, DIP-ANT
Anatomical
variations of
Mental nerve

2. Who may be interested?
 Oral surgeons  Dental
implantologists
 Digital radiology lab’s
 guided implantology lab’s
 General practioners
 Radiologists

3. 1- Mand. Incisive canal

4. Radiographic expression

5. Occurrence rate in literature
- occurrence 11 to 92% of cases pending the examination method used (so it is not uncommon!!)
- Panoramic radiographs have the least accuracy (11%)

6. 2- Ant. Loop of mental nerve

7. Radiographic expression

8. Occurrence rate in literature
 Solar et al. detected an AL in 60% (22 of 37) of dissected cadaver mandibles,
ranging in length from 0.5 to 5 mm (mean 1 mm).
 Neiva et al. reported the AL was present 88% of 22 cadavers and its length
ranged from 1 to 11 mm (mean 4.13 mm).
 Rosenquist detected AL in 24% (15 of 58) of cadaveric mandibles with loop
length variations from 0 to 1 mm.
 Seems to be not uncommon as well!!!

9. 3- Accessory mental foramen

10. Accessory mental nerve (Triple)

11. Occurrence rate in literature
 Gershenson et al. (1986) who examined 525 dry mandibles reported that 4.3%
mandibles had double mental foramina, and 0.7% mandibles had triple mental
foramina. Finally they found one mandible that had four mental foramina on
one side (0.1%)
 Serman (1989) examined 408 dry human mandibles and found one extra
foramen on one side in seven mandibles constituting 1.7%.
 Sawyer et al. In 1998 reported 5.9% accessory mental foramen in four ethnic
groups.
 Katakami et el. (2008) examined 150 patients retrospectively with limited
cone-beam computed tomography and depicted 16 double foramina (10.6%)
and triple mental foramina on one side (0.6%)
- A double mental foramen appears in approximately 1% in Egyptians.
- Which means that one of this will visit your clinic someday.

12. 4- Absence of mental foramen

13. Occurrence rate in literature
- THIS IS ULTIMATELY RARE.

14. 5- Position of mental foramen

15. Occurrence rate in literature
- It varied from mesial to the 1st premolar apex to below the 1st molar apex.
- It is very uncommon to pass mesially the apex of the canine.

16. RACE
- in Mongoloid population, the mental foramen was located in line with the longitudinal axis
of the lower second premolar teeth.
- In Caucasians, the mental foramen was more medially located, between first and second
premolar.
- in Black populations it was found to be more posterior, between second premolar and first
molar.

17. Why should I know about these
variations?

18. To avoid X-ray misdiagnosis..

19. Better implant planning..

20. To better expect and manage surgical
complications..

22. references
 Juodzbalys G, Wang HL, Sabalys G. Anatomy of Mandibular Vital Structures.
Part II: Mandibular Incisive Canal, Mental Foramen and Associated
Neurovascular Bundles in Relation with Dental Implantology. J Oral Maxillofac
Res 2010 (Jan-Mar);1(1):e3.
 Anwar Ramadhan, Elias Messo, Jan-Michaél Hirsch. Anatomical Variation of
Mental Foramen. A case report. Stomatologija, Baltic Dental and maxillofacial
Journal, 12: 93-6, 2010.
 Tabinda Hasan. Bilateral caroticoclinoid and absent mental foramen: rare
variations of cranial base and lower jaw. ITALIAN JOURNAL OF ANATOMY AND
EMBRYOLOGY (IJAE). Vo l. 118, n . 3: 28 8 -297, 2013.
 Tabinda HASAN, Mahmood FAUZI, Deeba HASAN. Bilateral absence of mental
foramen – a rare variation. International Journal of Anatomical Variations
(2010) 3: 167–169.