The DIAGNOdent Laser Pen is a tool that we use to help us detect dental caries (decay) in your mouth. Dentists often experience anxiety when attempting to diagnose the phenomenon known as hidden caries. A suspicious-looking tooth presents a treatment dilemma for dentists. Should the tooth be opened up? What if no caries is found? Should the tooth just be watched, or does that give caries more time to destroy the tooth's surface? Over 90% accurate in detecting lesions not detectable with an explorer or bite-wing X-rays.