BACKGROUND: Caries is a multifactorial and infectious disease. To diagnose caries in clinical practice, a combination of clinical examination with mirror and probe (visual-tactile examination) is used today, as well as in some cases standardized x-rays called bitewing x-ray (bw). Visual-tactile examination is enough to diagnose caries on buccal and lingual/palate surfaces. However, for approximal surfaces, X-rays are often required to ensure diagnosis and to assess the spread of a caries lesion in the tooth. Bitewing X-rays are the single best diagnostic tools for diagnosing caries in approximal surfaces. An X-ray examination should always be performed on individual indications. At bw the radiation doses are small. Nevertheless, it is important to weigh risks against the benefit to avoid unnecessary radiation. Reducing the number of dental radiographs is also important from the perspective of safe dental care where one strives to make use of and not harm.