Abstract: A dental X-ray reference device comprised of a radiopaque marker having a known dimension and a tooth overlay molding adapted to secure the radiopaque marker in close proximity to a tooth. Also disclosed is a process for measuring teeth for implant placement or root canal treatment. This process comprises the steps of providing a dental X-ray reference device comprised of a radiopaque marker having a known dimension and a tooth overlay molding adapted to secure the radiopaque marker in close proximity of a tooth, or alveolar ridge. The dental X-ray reference device is then positioned in a mouth of a patient. The radiopaque marker is positioned over the edentulous area or over a tooth. Then an X-ray sensor is positioned behind the tooth, or alveolar ridge, and behind the X-ray reference device. A radiograph of the tooth or alveolar ridge, and the radiopaque marker is taken.