Validity and Reliability of Intraoral Ultrasonography for the Assessment of Human Periodontal Structures

Purpose Recent advances in intraoral ultrasonography (US) have enabled quantitative assessment of periodontal tissues; however, limitations remain regarding applicable measurement sites and structural visualization. This study aimed to investigate the anatomical accuracy and measurement reproducibility of intraoral US imaging for soft and hard periodontal tissues, comprising buccal and lingual (or palatal) surfaces, as well as dental calculus. Methods US images were obtained from the gingival margin (GM), alveolar bone crest (ABC), and cementoenamel junction (CEJ) of 108 teeth from fixed human cadavers. These regions were then sectioned and scanned to generate reference images. Three parameters were measured: (1) the distance between the ABC and GM, (2) the distance between the ABC and CEJ, and (3) the linear length of dental calculus on the tooth surface. All measurements were conducted twice by the same examiner for reliability analysis. Results The results revealed that US images clearly delineated the gingiva, CEJ, alveolar bone, and calculus according to their echogenic characteristics. No statistically significant differences were found between ultrasound and reference measurements ( p  > 0.05). Intraclass correlation coefficients ranged from 0.68 to 0.91, and Bland–Altman analysis revealed 95% limits of agreement within ± 1.46 mm for ABC–GM and ABC–CEJ, and ± 0.47 mm for calculus length. These findings confirm that intraoral US reliably reflects anatomical structures with high fidelity. Conclusion The study indicates the potential of US as a valid and reproducible modality for comprehensive periodontal evaluation, overcoming previous limitations that focused solely on individual components.