Hidden occlusal caries lesion--a diagnostic challenge

In the 1980s a new type of caries lesion was added to the lexicon of Dentistry, namely, the Hidden Caries. The hidden caries is a sub-type of the occlusal pit and fissure caries type, and is defined as a dentinal caries lesion nearby the occlusal surface of the tooth, seen on a radiograph, where the occlusal enamel remains intact or is minimally perforated. The cariogenic bacteria penetrate into the enamel via a minimal hole in the enamel surface, but once reaching the softer dentine, their progression is less restricted, and meanwhile the fluoridated enamel undergoes remineralization thus covers the traces. Hidden caries lesions challenge the dental surgeon in diagnosis, treatment planning and research, in particular because of their 'hidden' nature. The potential diagnostic errors regarding hidden caries are undiagnosing, false-positive diagnosing, and misdiagnosing. The article reviews and demonstrates the differential diagnosis of a radiolucent spot on the occlusal dentin layer in posterior bitewing radiograph.