Identification of the mandibular vital structures: practical clinical applications of anatomy and radiological examination methods

Abstract

Objectives: The purpose of this article was to review the current available clinical techniques and to recommend the most appropriate imaging modalities for the identification of mandibular vital structures when planning for oral implants.

Material and methods: The literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were mandibular canal, mandibular incisive canal, mental foramen, anterior loop of the mental nerve, radiography, dental implants. The search was restricted to English language articles, published from January 1976 to January 2010.

Results: In total 111 literature sources were obtained and reviewed. The peculiarities of the clinical anatomy of mandibular canal, mandibular incisive canal, mental foramen and anterior loop of mental nerve were discussed. Radiological diagnostic methods currently available for the identification of the mandibular vital structures when planning for oral implants were presented. Guidelines for the identification of the mandibular vital structures in dental implantology were made.

Conclusions: The proposed guideline provides clinicians a tool in proper identifying the important mandibular vital structures thus minimizing the potential complications during implant surgery.

Keywords: chin; cross-sectional anatomy; dental implants.; inferior alveolar nerve; mandible; radiography.

Figure 1

A = mandible is divided into edentulous jaw segments that consists of alveolar and basal bone for planned implant bed. B = the vertical dimension (H) of the planned implant is determined by the distance between the alveolar ridge crest and mental foramen. C = the vertical dimension (H) of the planned implant is determined by the distance between the alveolar crestal ridge and mandibular canal. The horizontal EJS dimensions: length (L) in all cases is determined by the distance between neighbouring teeth or implants and width (W) is determined by the alveolar process width measured at the level of 3 mm (W1) and 6 mm (W2) from the crest of alveolar ridge.

Figure 2

A = Thin crestal ridge was reduced to create wide recipient bed for planned implant installation. In such cases, the heights of EJS would have been shortened by 1 to 3 mm at least. B and C = another implant treatment option: crestal ridge preservation and dental implant surgical placement with subsequent alveolar process augmentation.

Figure 3

Asymmetry or reshape of the crestal bone influences the height (H1 and H2) of bone, apparently available for the implant accommodation above the canal (C), as it was seen on the panoramic film.

Figure 4

The position of mandibular canal (C1 and C2) in horizontal plane influences the apparent height (H1 and H2) of bone available for implant accommodation.

Figure 5

The orthopantomograph shows the disrupted (arrows) superior border of mandibular canal and cancellous bone which has few and thin trabecullae.

Figure 6A

Computed tomographic images: mental foramen (arrow) detection.

Figure 6B

Computed tomographic images: mandibular canal detection (arrow).