The aim of this study was to evaluate the usefulness of 40 MHz periodontal ultrasonography in the assessment of gingival inflammation, following professional teeth cleaning. Material and methods: The study was performed on 18 teeth without restorations having subgingival calculus (upper and lower premolars and frontal teeth). After the clinical exam the Gingival Index and the Sulcus Bleeding Index were calculated. Then a 40MHz transducer (ULTRASONIX SonoTouch device) was used to obtain longitudinal sections in the frontal plane. Three measurements were performed: alveolar crest -cementumenamel junction distance (ACJ), gingival height (GH), and gingival width (GW). Professional cleaning was performed by ultrasound scaling (SatelecP5 booster, France) and airflow (NSK, Japan). Two and seven days after the first evaluation, ultrasonographic and clinical examinations were repeated. Results: Two days after the treatment the median value of the ACJ, was 2.70 (2.38; 2.95) mm, whereas 7 days after treatment it was 2.55 (2.45; 3.01) mm. The intraclass correlation coefficient for ACJ measurement was 98.8 (p<0.001).The values obtained measuring GH [3.84(3.44; 4.27) mm vs. 3.52 (3.00; 3.76) mm] and GW [(1.81 (1.65; 1.95) mm vs.1.62 (1.40; 1.95) mm) had statistically significant differences between the 2nd and 7th day. Conclusions: Periodontal ultrasonography is a highly precise and reproducible imagistic method, with which bone resorption, gingival inflammation as well as the presence or absence of subgingival calculus can be assessed.