Have you ever called out loudly toward the mountains? “Echo” might have responded to you using the same words you said. Today, I would like to discuss another kind of “echo” — those captured in ultrasound diagnostic imaging — with a particular focus on intraoral ultrasonography in dentistry.

Intraoral ultrasonography has been used to detect and diagnose soft-tissue lesions in areas such as the tongue and oral mucosa. More recently, however, it has gained attention as a promising non-invasive imaging modality capable of detailed evaluation of the teeth and the periodontal tissues. As the technology continues to advance, it holds significant potential to transform periodontal diagnostics and improve patient care through precise, non-invasive, real-time imaging.

This lecture will begin with a comprehensive overview of the principles, strengths, and limitations of ultrasound diagnostics, highlighting representative clinical applications of both extraoral and intraoral ultrasound techniques currently used in dentistry.

Next, I will focus specifically on intraoral ultrasonography for periodontal tissues and introduce ongoing research aimed at validating its clinical utility. These efforts include confirming periodontal tissue anatomy and assessing the accuracy and reproducibility of measurements such as alveolar bone levels and soft-tissue morphology. Within this section, special emphasis will be placed on our own research, which discusses the usefulness of ultrasonography in classifying furcation involvement and assessing peri-implant osseous defects using ultrasonography. Our studies demonstrate that this modality can successfully visualize complex periodontal structures, thereby supporting more accurate diagnosis and treatment planning.

Finally, I will discuss future directions: the innovative coupling materials to enhance image quality and patient comfort, as well as the refinement of transducer designs to improve accessibility and usability within the oral cavity. These advancements highlight an exciting future where ultrasonography has an increased role in helping clinicians with diagnostic imaging of the oral cavity without the risk of ionizing radiation.