Caries detection by clinical examination with or without radiograph

Abstract

OBJECTIVE: The aim of this study was to compare the diagnosis of dental caries in an oral epidemiological survey of young adults between using clinical examination alone and with supplement of bitewing radiographs. METHODS: A survey of a sample of 736 new students of the University of Hong Kong (aged 18-24 years) was conducted when they joined the university. Two dentists in the on-campus dental clinic examined these students using mouth mirrors and probes under optimal lighting. The dentists were calibrated before the survey and duplicate examinations were performed to monitor inter-examiner variation during the survey. Bitewing radiographs of all the students were taken after the examination and these formed part of their clinical record. A random sample of 200 sets of bitewing radiographs were examined by a third dentist who was not involved in the clinical examinations. The information recorded included the status of each tooth of the surveyed students (sound, decayed, filled or missing). Caries was recorded when a lesion extended into dentin. RESULTS: About one third (35.4%) of the dental caries lesions in the posterior teeth were not detected from reading the radiographs but were detected in the clinical examinations. About half (51.4%) of the caries lesions were found on the bitewing radiographs only, leaving 13.2% of the lesions being detected by using both methods. With the supplement of bitewing radiographs, there was a 106% increase in the number of diagnosed dentin caries lesions in this young adult population. This lead to a correction factor of 1.13 for adjustment of the mean DMFT score obtained from conducting clinical examinations alone. CONCLUSION: Due to the significant number of clinically undetected caries lesions it may be advisable to use a correction factor to adjust the DMFT scores obtained from epidemiological surveys when bitewing radiographs are not available.