High-Frequency Ultrasound for Detecting Periodontal Inflammation: A Preclinical Diagnostic Accuracy Study

Aim: Ultrasonography (US) has shown accuracy in imaging healthy periodontium. This study aims to evaluate the feasibility and accuracy of US for estimating dimensions of inflamed periodontium induced by ligature and bacteria. Methods: Periodontal tissues of maxillary as well as mandibular premolars and molars in six female mini pigs were treated with ligature and three strains of bacteria for 4-10 weeks. Before euthanization, the periodontium was imaged with US. After euthanization, cone-beam computed tomography (CBCT) scans and histology were performed. Soft and hard tissue measurements by calibrated and masked examiners from US, CBCT, and histology were statistically compared. Results: Seventy-one histological samples with corresponding CBCT and US scans were available for analysis. Overall, there was a good to excellent agreement between histology and US (ICC: 0.77-0.96) for parameters such as Soft Tissue Thickness (STT), Gingival Recession, Crestal Bone Thickness (CBT), and the bone-to-cemento-enamel junction (B-CEJ) distance. However, discrepancies were observed for STT at 3 mm below the CEJ and Soft Tissue Height (STH) (ICC: 0.44 and 0.54, respectively). CBCT showed lower agreement with histology, particularly for thin CBT (< 1 mm), with an ICC of 0.20, compared to 0.90 for US vs. histology. CBCT failed to identify crestal bone in 14 cases when the crestal bone was thin. Notably, CBCT results differed more from histological measurements than US in assessing B-CEJ and thin CBT. Conclusion: US demonstrated substantial potential as a transformative tool for periodontal diagnostics, exhibiting high agreement with histology in determining critical parameters. Compared to CBCT, US offered advantages, particularly in cases with thin crestal bone.