|Year : 2017 | Volume
| Issue : 1 | Page : 41-45
Prevalence and location of the anterior lingual foramen: A cone-beam computed tomography assessment
Ahmad Assari1, Hesham Almashat2, Abdulah Alamry3, Bishi Algarni2
1 Department of Oral and Maxillofacial Surgery and Diagnostic Sciences, Riyadh Colleges of Dentistry and Pharmacy, Riyadh, Kingdom of Saudi Arabia
2 Riyadh Dental Center, King Saud Medical City, Riyadh, Kingdom of Saudi Arabia
3 Ministry of Health, King Saud Medical City, Riyadh, Kingdom of Saudi Arabia
|Date of Web Publication||14-Feb-2017|
Department of Oral and Maxillofacial Surgery and Diagnostic Sciences, Riyadh Colleges of Dentistry and Pharmacy, P.O. Box 84891, Riyadh 11681
Kingdom of Saudi Arabia
Source of Support: None, Conflict of Interest: None
Introduction and Aim: The anterior lingual foramen is an anatomic structure in the symphysis region of the mandible. There is little research on the incidence and prevalence of this structure. The aim of this study was to evaluate the prevalence and the location of the mandibular lingual foramen seen in CBCTs of a sample of the Saudi population.
Methodology: 160 CBCTs images of the mandible of Saudi individuals taken at the Riyadh dental center were evaluated (45 male and 112 female) on the axial, coronal and curved sections for the presence and the number of lingual foramina for each patient. The distance between each foramen and the inferior border of the mandible, and the distance between the foramen and the genial tubercle were measured.
Results: There was no statistically significant difference between male and females in the presence of the foramen. All CBCT scans showed presence of at least one lingual foramen in the mandible.
Conclusion: The prevalence of the mandibular lingual foramen seems to be nearly universal in the Saudi population. Surgeons looking to place implants in the mandibular anterior region should take cognizance of this fact in order to minimize the chance of complications.
Keywords: Anterior mandible, cone-beam computed tomography, dental implants, lingual foramen
|How to cite this article:|
Assari A, Almashat H, Alamry A, Algarni B. Prevalence and location of the anterior lingual foramen: A cone-beam computed tomography assessment. Saudi J Oral Sci 2017;4:41-5
|How to cite this URL:|
Assari A, Almashat H, Alamry A, Algarni B. Prevalence and location of the anterior lingual foramen: A cone-beam computed tomography assessment. Saudi J Oral Sci [serial online] 2017 [cited 2019 Oct 15];4:41-5. Available from: http://www.saudijos.org/text.asp?2017/4/1/41/200145
| Introduction|| |
Advances over the past century have meant that surgical procedures in the lower anterior segment of the mandible including orthognathic surgeries, dental implant placement, bone grafting, and lowering genial spines procedures of edentulous patients have become more frequent. This area has traditionally been considered a “surgical safe zone” because of the absence of important superficial nerves or vessels. However, recent reports of unexplained bleeding and sublingual hematoma after genioplasties and endosseous implant placement have spurred research into the content and the vascularity of the area.,,,,
The anastomosis of the two sublingual arteries has been suggested to be the blood supply of the chin.,, This single artery and its minor branches tend to exit the bone through structures that have been referred to in the literature as the anterior lingual foramina.,
The advent of computed tomography (CT) has enabled the detailed study of bony structures with accuracy that was previously only possible by examination of cadavers.,,, Cone-beam CT (CBCT) offers three-dimensional radiographic imaging with greatly reduced doses of radiation (as compared to traditional CT) and is becoming a routine diagnostic tool in implant planning. The occurrence and location of the anterior lingual foramen have been studied in both dried mandibles and with the help of CT and CBCT scans.,,,,,,, Although the foramen has been found in 98%–99.04% of dried mandibles,, early CT evaluations have reported lower values ranging from 71% to 90%.,,,,,
Racial and ethnic variations in anatomical landmarks are not uncommon. There is little known about the incidence or location of the anterior lingual foramen in the Arab population. The aim of this study was to evaluate the prevalence and location of the anterior lingual foramen in a sample of Saudi individuals.
| Materials and Methods|| |
One hundred and sixty CBCT images of the mandibles of Saudi individuals (45 males and 112 females) taken using Kodak 9000c 3D (Eastman Kodak, Rochester, NY, USA) at the Riyadh Dental Center at King Saud Medical City were evaluated on the axial, coronal, and curved sections for the presence and the number of lingual foramina for each patient. The distance between each foramen and the inferior border of the mandible and the distance between the foramen and the anatomical midline of the mandible were measured and analyzed using a digital image analysis software (CS 3D Imaging Software version 3.1.9 – Carestream Dental LLC, Atlanta GA, USA) The software allowed for the examination of section in the form of 0.1 mm slices.
The anterior mandible area was examined in coronal, axial, and curved views. For each mandible, the genial tubercles and the inferior border of the mandible were identified as a landmark. Each of lingual foramina of the anterior mandible was also identified. The objects were identified on a 1 mm thickness views fabricated by the software. The transverse coordinates were measured from the lower border of the mandible at 1 mm slices, while the sagittal coordinates were measured from the midline of the mandible as generated by the software [Figure 1].
Localization of the foramen
The slices from the software program were used to localize the location of the foramen on two planes.
The vertical coordinates of the anatomical midline were subtracted from the vertical coordinate of the medial aspect of the anterior lingual foramen. The difference yielded the distance from the midline of the foramen. Since all scans were taken in a left-to-right manner, a positive value indicated a foramen on the right side while the negative value indicated a foramen on the left side.
The horizontal coordinates of the lower border of the mandiblewere subtracted from the horizontal coordinate of the lower border of the anterior lingual foramen. The difference yielded the distance of the foramen in mm from the lower border of the mandible [Figure 2].
|Figure 2: Moving along the transverse plane in one mm sections to determine distance of the foramen from the landmark (horizontal coordinates)|
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Number of foramina
The total number of anterior lingual foramina observed was tabulated and cross-tabulated according to gender.
Each scan was examined by two examiners who were initially calibrated to a master examiner (an implantologist with 5 years of experience using CBCT in implant planning). Interexaminer reliability was calculated using the Cronbach's alpha. The Cronbach's alpha was found to be 0.92.
The number of foramina in each patient was cross-tabulated according to gender and subjected to the Chi-square test to observe the significance of difference. The mean distance of the foramen from the lower border of the mandible and the midline was calculated along with the standard deviation (SD). The significance of difference in the position of the foramen between males and females was tested using the Student's t-test. The Spearman's rho was used to measure the presence or absence of correlation between the age of the subject and the number of foramina. All statistical analyses were carried out using SPSS 20.0, (SPSS for Windows; SPSS Inc., Chicago, IL, USA). The probability of error was set at P = 0.05 for all tests.
| Results|| |
The mean age of the population was 45.56 years (SD ± 16.5), and the youngest individual in the sample was 14 years old while the oldest was 92 years old. There was no statistically significant age difference between males (47.9 ± 17.6 years) and females (44.1 ± 15.9 years). All the 160 images examined showed at least one lingual foramen. 23.1% (37 images) showed the presence of a single lingual foramen, 38.8% (62 images) showed two lingual foramina, 26.9% (43 images) showed three foramina, 6.9% (11 images) showed four foramina, and 4.4% (7 images) showed 5 lingual foramina [Figure 3]. The Chi-square test showed that there was no significant difference in the pattern of distribution of foramina between males and females (χ2 = 1.958, P = 0.754).
|Figure 3: Distribution of population according to number of Foramina seen in each subject|
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The average distance of the foramina from midline was 21.1 ± 12.5 mm, and the average distance to the inferior border of the mandible was 29.2 ± 12.9 mm [Table 1]. The location of the foramina is significantly closer to the midline in males than in females, and the foramina are significantly higher to the lower border in females than in males [Table 2].
|Table 1: Average distance of the foramina from midline and lower border of the mandible|
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|Table 2: Gender differences in the position of the anterior lingual foramen from the midline and the lower border of the mandible|
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The Spearman's rho coefficient showed that there was no correlation between the age of the patient and the number of foramina seen (r = 0.063, P = 0.435). Similarly, no significant correlation was found between age and the horizontal position of the foramen (r = 0.01, P = 0.900) or the vertical position (r = −10.08, P = 0.916).
| Discussion|| |
Unexpected bleeding, during or after implant placement, is a complication that all surgeons wish to avoid. Reports of unexplained bleeding from sites in proximity to implants placed in the mandibular foramen stimulated research into the contents and location of the anterior lingual foramen.,, It is today widely accepted in literature that the foramen is an opening of the incisive canal and carries several accessory blood vessels that supply the anterior mandible.,,
Although there have been early cadaveric studies that have described the existence of the anterior lingual foramen, the advent of CT and later CBCT technology have seen an increased interest in the prevalence, location, and number of the anterior lingual foramen.,,,,,
The presence of the anterior lingual foramen in all the subjects in the present study suggests that the presence of an anterior lingual foramen is clinically interesting. Scaravilli et al. reported a prevalence of 90.35% in 103 CTs samples  while Liang et al. reported a 98% presence in their CT study. Near universal presence has been described by McDonnell et al., who found it in 99.04% of 314 dried mandible specimens. The role of improved imaging techniques in this variation must be taken into consideration given that more recent studies such as those of Cantekin et al. and Sheikhi et al. have also reported a universal prevalence of the lingual foramen in their CBCT assessments.
The influence of age on the position of certain mandibular landmarks such as the inferior alveolar canal and the mental foramen has been well documented in literature.,,,, However, little has been discussed in literature regarding the influence of age on the incidence and distribution of anterior lingual foramina. The results of our study seem to indicate that the location of the anterior lingual foramina does not appear to vary with age. Furthermore, there seems to be no increase or decrease in the number of foramina with age, suggesting that this is a true anatomical landmark rather than an artifact observed due to bone resorption.
McDonnell et al. evaluated the size and the content of the foramina; they postulated a lingual origin for the present artery rather than a termination of the inferior alveolar artery and that this artery is of a sufficient size to show difficulties in controlling intraosseous or soft tissue bleeding. This was in agreement with an ultrasound study by Lustig et al. measuring the blood flow and the diameter of the artery. The presence of minute nerves around the artery was suggested to be in charge for the vasomotor supply. Liang et al. examined the superior and the inferior foramen separately, in relation to the genial spines. They found that in the superior foramen, the contents were branches of the lingual artery, vein, and nerve, where the inferior showed branches of mylohyoid nerve and sublingual arteries. Considering the high prevalence and the vascular content of this foramen, injury to this vital structure may be seen commonly in surgical procedures. Thorough radiographic evaluation will be of great help in avoiding injury to these structures.
| Conclusion|| |
The prevalence of the mandibular lingual foramen seems to be nearly universal in the Saudi population. Surgeons looking to place implants in the mandibular anterior region should take cognizance of this fact to minimize the chance of complications.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]