The repeatability and reproducibility of gingival thickness measurement with an ultrasonic device

Successful periodontal and implant surgery as well as orthodontic treatment often depends on gingival and mucosal thickness. So far there has been no generally accepted protocol of measuring the thickness of gingiva by non-invasive methods.

The aim of the study was to evaluate the repeatability and reproducibility (%R&R) of the 20 MHz A-Scan ultrasonic device in measuring gingival thickness (GT) in the mucogingival complex.

A 2-stage study utilizing non-invasive ultrasonic methods was conducted. In the 1st stage, 3 operators got calibrated by measuring previously established GT in porcine cadaver jaws. In the 2nd stage, 1 periodontally healthy subject was recruited in the study. Three operators performed the measurements of GT in maxillary left central and lateral incisors and canines, using the 20 MHz A-Scan ultrasonic device with a probe of 1.7 mm in diameter. The thickness was measured in 4 standardized points located in the free gingiva (FGT), supracrestal gingiva (SGT), crestal gingiva (CGT) and the mucosa (MGT).

The analysis of variance (ANOVA) method was used to quantify %R&R. The repeatability and reproducibility of the measurements was 8.4%. Interobserver reproducibility varied from 0.8% to 13.4%. The average intraobserver coefficient of variation (CV) was 6.6% (1.9-13.6%). The median of the reproducibility of all measurements was 8.1 %. Nevertheless, the median of CV was variable to the observer, i.e. 5.4%, 6.5%, 6.4%.

The obtained results in %R&R prove the good recognition of methodology as well as the usefulness of the device. Non-invasive ultrasonic biometer GT measurements are crucial in periodontology as well as in other fields of dentistry.