The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998, based on the National Health Promotion Act

The oral examination of KNHANES is used as key statistical data for the establishment and evaluation of national oral health policies. Dental caries and periodontal diseases are conditions that are prone to inter-investigator variability due to differing judgment criteria, Therefore, training and systematic quality management of investigators are essential to ensure the reliability and objectivity of the examination.

Panoramic radiographic imaging was added to improve reliability and objectivity. A vehicle equipped with a panoramic X-ray machine was developed to travel nationwide for imaging. To improve the quality of imaging, operators received theoretical and practical imaging training. An interpretation guideline was developed. Five oral and maxillofacial radiologists interpreted the images according to the guidelines. Two radiologists interpreted each image, and in cases of disagreement, a decision was made through discussion.

The oral examination involved visual inspections for identifying dental caries, restoration, prosthesis, as well as periodontal probing for measuring periodontal pockets. In panoramic radiographs, dental caries, alveolar bone loss and calculus were assessed.

When panoramic radiographs were added to the oral examination, the prevalence of proximal caries and calculus increased due to its superior detection ability for interproximal decay and interproximal calculus. There was a low correlation between periodontal pockets and alveolar bone loss. Although the sample size was small and not representative, utilizing panoramic radiographs seems to aid in accurately determining the prevalence of dental caries and calculus. Since the degree of alveolar bone loss does not accurately reflect the current state of periodontal disease, it could be used as an indicator of accumulated periodontal disease outcomes in the health and nutrition survey.