Ultrasonographic characterization of lingual structures pertinent to oral, periodontal, and implant surgery

Objectives Increased applications of ridge augmentation in the lingual posterior mandible call for an urgent need to study its anatomy. Therefore, our first aim was to validate ultrasound in measuring the mandibular lingual structures in human cadavers. Secondarily, to test its feasibility in imaging the lingual nerve in live humans. Materials and methods Nine fresh un-embalmed fully/partially edentulous cadaver heads were utilized for aim 1. Three areas in the lingual mandible were imaged (mandibular premolar, molar, and retromolar). Immediately after, biopsies were harvested from each site. The thickness of the mucosa, mylohyoid muscle, and lingual nerve diameter was measured via ultrasound and statistically compared to histology. Similarly, the lingual nerve in live humans was also imaged. Results None of the differences between the ultrasound and histology measurements reached statistical significance (p > .05). The mean mucosal thickness via ultrasound and histology was 1.45 +/- 0.49 and 1.39 +/- 0.50 mm, 5 mm lingual to the mylohyoid muscle attachment. At 10 mm beyond the attachment, the ultrasound and histologic values were 1.54 +/- 0.48 and 1.37 +/- 0.49, respectively. The mean muscle thickness measured via ultrasound and histology was 2.31 +/- 0.56 and 2.25 +/- 0.47 mm, at the 5 mm distance. At the 10 mm distance, the measurements were 2.46 +/- 0.56 and 2.36 +/- 0.5 mm, respectively. The mean ultrasonic lingual nerve diameter was 2.38 +/- 0.44 mm, versus 2.43 +/- 0.42 mm, with histology. The lingual nerve diameter on 19 live humans averaged to 2.01 +/- 0.35 mm (1.4-3.1 mm). Conclusions Within its limitations, ultrasound accurately measured mandibular lingual soft tissue structures on cadavers, and the lingual nerve on live humans.