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(Radiology. 2001;220:186-189.)
© RSNA, 2001

Head and Neck Imaging

Lingual Vascular Canals of the Mandible: Evaluation with Dental CT1

André Gahleitner, MD, Ursula Hofschneider, MD, Gabor Tepper, MD, Michael Pretterklieber, MD, Susanne Schick, MD, Konstantin Zauza, MD and Georg Watzek, MD

1 From the Department of Radiology (A.G., S.S.) and Institute of Anatomy (M.P.), University of Vienna Medical School, Währingerstr 25a, A-1090 Vienna, Austria; and the Department of Oral Surgery and Prosthodontics, University of Vienna Dental School, Austria (U.H., G.T., K.Z., G.W.). Received October 13, 2000; revision requested December 5; revision received January 12, 2001; accepted January 26. Address correspondence to A.G. (e-mail: andre.gahleitner@univie.ac.at).


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
PURPOSE: To evaluate whether dental computed tomography (CT) can depict the frequency, diameter, position, and direction of vessels entering the mandible through lingual bone canals.

MATERIALS AND METHODS: Thirty-two consecutive patients underwent preimplantation CT of the lower jaw and examination for the presence, number, location, diameter, and direction of lingual canals entering the mandible. In addition, three cadaver mandibles were investigated with dental CT and subsequently dissected to confirm the CT findings.

RESULTS: All patients demonstrated at least one lingual vascular canal, and 20 (63%) had multiple (two to five) canals. The typical lingual canal locations were the midline of the mandible and the premolar region. The mean diameter of the lingual canals was 0.7 mm ± 0.3 (SD) (range, 0.4–1.5 mm) in the midline and 0.6 mm ± 0.2 (range, 0.3–1.2 mm) in both premolar regions of the mandible. Examination results in the three cadaver mandibles confirmed the CT findings in those mandibles.

CONCLUSION: Dental CT can depict the occurrence, position, and size of the lingual vascular canals of the mandible. Radiologists should be aware of this anatomic feature and its possible implications.

Index terms: Computed tomography (CT), three-dimensional, 243.12117 • Computed tomography (CT), treatment planning, 243.12111, 243.12117 • Jaws, CT, 243.12111, 243.12117, 243.92


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Dental computed tomography (CT) has proved to be an excellent procedure for characterizing the anatomy and dental-related abnormalities of the jaw (1–5). It offers the additional possibility of multiplanar reconstructions in high-quality and true-to-size hard copies. CT is particularly important for preoperative planning in dental implantology because it aids in the appropriate choice of implant size and helps to avoid injury of critical structures such as the mandibular canal or maxillary sinus.

The insertion of dental implants, about 1.4 million per year worldwide, in the interforaminal region of the anterior mandible (between the mental foramina) is a standard procedure in dentistry and maxillofacial surgery (Streamline product catalog, Gothenburg, Sweden: Nobel Biocare, 2000) Because injury of the mandibular canal in this region is not possible, dental implants are considered relatively safe. However, investigators in several studies (6–11) have reported life-threatening conditions caused by profuse bleeding from the implantation site after interforaminal implantation. This complication was not always noticed immediately during the procedure and led to upper-airway obstruction because of the development of a large hematoma within the floor of the mouth. Investigators in anatomic studies (12–14) have postulated that vessels entering the mandible through bone canals from the lingual (inner) side can cause such bleeding when the vessels are injured by the dentist’s drill.

The purpose of this investigation was to evaluate whether dental CT can depict the frequency, diameter, direction, and position of the vessels entering the mandible through the lingual bone canals.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
REFERENCES
 
Thirty-two consecutive patients (19 women, 13 men; mean age, 56 years; age range, 18–76 years) underwent dental CT of the mandible for preimplantation evaluation of jaw anatomy. CT images (Tomoscan SR-6000; Philips Medical Systems, Best, the Netherlands) were obtained with a standard protocol (1.5-mm section thickness, 1-mm table feed, 75 mA/s, 2-second scanning time per section, 120 kV, and 512 matrix). After acquisition of the images in the transverse plane parallel to the mandible base, multiplanar reconstructions based on the dental CT protocol were obtained in the orthoradial and panoramic plane by using a dental software package (EASY VISION Release 2.1; Philips Medical Systems) on a workstation. The images were evaluated by a radiologist, a dental radiologist, and a dentist in a single session. Agreement was reached by means of a majority decision (at least two of three observers agreed).

The presence, number, diameter, and direction of the lingual vascular foramina and their canals were evaluated. In addition, the exact location of each canal was obtained by measuring the distance to the canal entrance from the menton (anterior midline of the mandible) and from the inferior border of the mandible.

To compare the CT findings with anatomic findings, three randomly selected adult cadaver mandibles (one female and two male, with no signs of previous surgery) were scanned by using the dental CT protocol mentioned earlier and were subsequently dissected. Attention was paid solely to whether a vessel entered the mandible from the lingual side and if it was associated with a corresponding lingual canal. Sectioning (orthoradial cut) was performed to demonstrate the canal’s course.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
REFERENCES
 
We found two typical locations of the lingual mandibular canal: either in or near the midline (median lingual canal [MLC]) or lateral lingual canals (LLCs) in both premolar regions. At least one lingual canal was present in all patients, with the total number of canals ranging from one to five for each patient; one (3%) of the 32 patients presented with five canals; three (9%), with four canals; four (12%), with three canals; 12 (38%), with two canals; and 12 (38%), with one canal.

The diameter of the MLCs was 0.4–1.5 mm in the midline (mean diameter, 0.7 mm ± 0.3 [SD]). The entrance of these canals was located between the spinae mentalia at a mean of 10.2 mm ± 5.5 above the mandible base. MLCs progressed in an anterior and slightly caudal direction (Figs 1, 2).



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  		Figure 1. Transverse CT scan of the mandible with orthoradial reconstruction (upper left) through the midline (straight vertical line). An MLC (arrow) is visible in the orthoradial reconstruction and enters the mandible from the lingual side.

 


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  		Figure 2. Orthoradial photograph of a cadaver mandible in the midline shows an MLC (arrow).

 
The LLCs on either side were slightly smaller, with a diameter of 0.3–1.2 mm (mean diameter, 0.6 mm ± 0.3). These canals typically entered the mandible in the premolar region and proceeded in a mesial (toward the midline) direction. Both LLCs were positioned symmetrically a mean of 23.4 mm ± 4.4 distal to the menton and 5.3 mm ± 3.3 above the mandible base (Fig 3). The results are summarized in the Table.



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  		Figure 3a. (a) Transverse CT scan of the anterior mandible shows a large LLC (arrow) on the right side. (b) Posterior 3D reconstruction of the inner surface of the mandible, viewed from behind, in the same patient as in a shows a canal entrance (arrow) on the right side of the mandible.

 


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  		Figure 3b. (a) Transverse CT scan of the anterior mandible shows a large LLC (arrow) on the right side. (b) Posterior 3D reconstruction of the inner surface of the mandible, viewed from behind, in the same patient as in a shows a canal entrance (arrow) on the right side of the mandible.

 

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  		Evaluation of Mandibular Lingual Vascular Canals

 
Of the three cadaver mandibles investigated with dental CT, three had an MLC, and one had an additional LLC. The mandibles were subsequently dissected, and it was possible to confirm the CT findings; the right and left sublingual artery joined to form a common single vessel entering the mandible in the midline at the position of the MLC. The course of the MLC was demonstrated with an orthoradial cut of the mandible in the midline (Fig 2). It was also possible to demonstrate that a branch of the sublingual artery entered the mandible in the premolar region, in which dental CT showed an LLC (Fig 4).



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  		Figure 4a. (a) Paraorthoradial CT reconstruction of a cadaver mandible with a visible LLC (arrow) entering the mandible from the lingual side at the left premolar region (straight line). (b) Dissection photograph of the cadaver mandible (view of inner side of right mandible) demonstrates a branch of the sublingual artery (arrows) entering the mandible (arrowheads) at the position of the LLC in a.

 


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  		Figure 4b. (a) Paraorthoradial CT reconstruction of a cadaver mandible with a visible LLC (arrow) entering the mandible from the lingual side at the left premolar region (straight line). (b) Dissection photograph of the cadaver mandible (view of inner side of right mandible) demonstrates a branch of the sublingual artery (arrows) entering the mandible (arrowheads) at the position of the LLC in a.

 

   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
Median Lingual Canals
Because of prior reports on life-threatening bleeding in the mouth floor after implant placement (6–11), studies have been performed to investigate the anatomy and vascular supply of the mandible. McDonnell et al (15) have reviewed several anatomic studies and reported an artery entering the mandible through a canal from the lingual side in the mental region and arising from an anastomosis of both sublingual arteries. These authors also reported the difficulties of radiologic depiction of the MLC with the conventional technique. When the x-ray beam was not oriented parallel to the canal, the canal could not be depicted; this was the case in 49% of specimens. Poyton and Pharoah (16) also reported the MLC as visible in only a small percentage of conventional radiographs of the incisor region.

Lateral Lingual Canals
With regard to the LLC, authors of anatomic studies (17,18) have described branches of the sublingual artery that enter the mandible in the premolar region. Schiller and Wiswell (18) reported the mean diameter of the LLC as 0.45 mm; the LLC was present in 63% of cases. To our knowledge, the lingual canals in this region have not yet been assessed with conventional radiography; this fact is attributable to the thin cortication and to the fact that the canal follows a mesial course, which would be perpendicular to the x-ray beam and hence not visible.

Dental CT
CT has the advantage of not being sensitive to beam orientation. Thus, we found it possible to visualize the LLCs and MLCs with CT more easily than was reported with conventional radiographic results (15,16), and our results with regard to the frequency and size of the lingual canals correlate well with the results of anatomic studies (17,18). The small difference in the size values of the canals can probably be attributed to the fact that the smallest canals were too small to be visible because of the limited resolution capability of CT.

Hemorrhage in the Floor of the Mouth
Mason et al (10) have summarized several reports on major hemorrhage in the floor of the mouth caused by bleeding from different surgical procedures and implant placement in the mental region. They therefore recommend that appreciation of the sublingual artery anatomy with the divisions in the floor of the mouth is mandatory for those performing mandibular implantation. DuBrul (17) noted that the sublingual artery running along the floor of the mouth can be of considerable size in the region of the molars and premolars and therefore is prone to substantial bleeding when injured. It can be assumed that the diameter of the lingual vascular channel is proportional to the diameter of the entering artery and to the potentially increased risk of hemorrhage of the floor of the mouth when injured. This injury probably occurs during drilling of the implantation site or final positioning of the implant where the artery enters the MLC or LLC. The newer augmentative techniques to gain bone volume, such as lateral and onlay graft or osteodistraction of the mandible, also have a potential for vascular injury and subsequent bleeding. Although smaller canals with a diameter of less than 1 mm are unlikely to cause a major hematoma, we believe that larger canals should be described in the radiologic report.

The number of patients who undergo implantation has increased dramatically in the past several years and requires optimum preoperative planning. As a state-of-the-art technique, dental CT offers the advantage of proper anatomic delineation of the jaw and depiction of the lingual vascular canals of the mandible, hence reducing the risk of implantation surgery in the preoperative phase.

In summary, dental CT for preimplantation assessment of jaw anatomy can demonstrate the occurrence, position, and size of the lingual vascular canals of the mandible. Radiologists should be aware of this anatomic feature and its possible implications.


   FOOTNOTES
 
Abbreviations: LLC = lateral lingual canal, MLC = median lingual canal

Author contributions: Guarantors of integrity of entire study, A.G., G.W.; study concepts, U.H., A.G.; study design, G.T., S.S.; literature research, M.P., S.S.; clinical studies, U.H., G.T.; data acquisition, U.H., A.G.; data analysis/interpretation, U.H., K.Z.; manuscript preparation and definition of intellectual content, A.G.; manuscript editing, G.T.; manuscript revision/review, S.S.; manuscript final version approval, A.G., G.W.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 

  1. Abrahams JJ. Anatomy of the jaw revisited with a dental CT software program. AJNR Am J Neuroradiol 1993; 14:979-990.[Abstract]
  2. Abrahams JJ, Hayt MW. Dental CT in pathologic changes of the maxillo-mandibular region. Radiologe 1999; 39:1035-1043[German].[CrossRef][Medline]
  3. Abrahams JJ, Berger SB. Inflammatory disease of the jaw: appearance on reformatted CT scans. AJR Am J Roentgenol 1998; 170:1085-1091.[Abstract/Free Full Text]
  4. Klein HM, Fuhrmann R, Diedrich P, Gunther RW. High-resolution CT of the dentate alveolar ridge in comparison with histological thin section preparations. Rofo Fortschr Geb Rontgenstr Neuen Bildgeb Verfahr 1993; 158:187-191.[Medline]
  5. Dula K, Buser D, Porcellini B, Berthold H, Schwarz M. Computed tomography/oral implantology. I. Dental CT: a program for the computed tomographic imaging of the jaws—the principles and exposure technic. Schweiz Monatsschr Zahnmed 1994; 104:450-459[French].
  6. Kattan B, Snyder HS. Lingual artery hematoma resulting in upper airway obstruction. J Emerg Med 1991; 9:421-424.[CrossRef][Medline]
  7. Krenkel C, Holzner K, Poisel S. Hematoma of the mouth floor following oral surgery and its anatomical characteristics. Dtsch Z Mund Kiefer Gesichtschir 1985; 9:448-451[German].[Medline]
  8. Krenkel C, Holzner K. Lingual bone perforation as causal factor in a threatening hemorrhage of the mouth floor due to a single tooth implant in the canine region. Quintessenz 1986; 37:1003-1008[German].[Medline]
  9. Laboda G. Life-threatening hemorrhage after placement of an endosseous implant: report of case. J Am Dent Assoc 1990; 121:599-600.[Abstract]
  10. Mason ME, Triplett RG, Alfonso WF. Life-threatening hemorrhage from placement of a dental implant. J Oral Maxillofac Surg 1990; 48:201-204.[Medline]
  11. Ratschew C, Czernicky W, Watzek G. Lebensbedrohende blutung nach implantation im unterkiefer. Dtsch Zahnärztl Z 1994; 49:65-67.
  12. Cadenat H, Barthelemy R, Combelles R, Fabie M, Maneaud M. Importance of mandibular vascularization in maxillofacial surgery. Rev Stomatol Chir Maxillofac 1972; 73:60-65.[Medline]
  13. Chase CR, Hebert JC, Farnham JE. Post-traumatic upper airway obstruction secondary to a lingual artery hematoma. J Trauma 1987; 27:953-954.[Medline]
  14. Hofschneider U, Tepper G, Gahleitner A, Ulm C. Assessment of the blood supply to the mental region for reduction of bleeding complications during implant surgery in the interforaminal region. Int J Oral Maxillofac Implants 1999; 14:379-383.[Medline]
  15. McDonnell D, Reza Nouri M, Todd ME. The mandibular lingual foramen: a consistent arterial foramen in the middle of the mandible. J Anat 1994; 184:363-369.
  16. Poyton H, Pharoah M. Oral radiology 2nd ed. Toronto, Canada: Decker, 1989; 56-59.
  17. DuBrul EL. Sicher’s oral anatomy 7th ed. St Louis, Mo: Mosby, 1980; 427-447.
  18. Schiller W, Wiswell O. Lingual foramina of the mandible. Anat Rec 1954; 119:387-390.[Medline]



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