Potential of Panoramic Radiography as a Screening Method for Oral Hypofunction in the Evaluation of Hyoid Bone Position

Abstract

The hyoid bone is located in the middle of the cervical muscles involved in oral masticatory function. The position of the hyoid bone is commonly determined by lateral cephalometric analysis. Although cephalometric radiography is commonly used in orthodontic treatment, the modality remains rare; routine dental care would benefit from precise identification of hyoid bone location using a more common modality, such as panoramic radiography. The purpose of this study was to investigate the usefulness of panoramic radiography compared to lateral cephalometric radiography for evaluating hyoid bone position as a potential screening method for oral hypofunction. The study included 347 patients referred for both a panoramic radiograph and a lateral cephalometric radiograph. The patients were divided into the following five groups according to the appearance of the hyoid bone in the panoramic radiograph: Group 1: hyoid bone could not be observed, or part of the greater horn was observed; Group 2: part of the hyoid body was observed, but not the most supero-anterior point of the hyoid bone; Group 3: the most supero-anterior point of the hyoid bone was observed; Group 4: all of the hyoid body was observed; Group 5: the hyoid body overlapped the mandible. The gold standard for measurement of hyoid bone position is the lateral cephalometric radiograph. Hyoid bone position as revealed by lateral cephalometric radiograph was compared among the groups. Hyoid bones that were observed in higher positions on lateral cephalometric radiograph were also observed in higher positions on panoramic radiograph. Hyoid bone position can be assessed by panoramic radiography, and this modality might be useful as a screening method for oral hypofunction.