Clinical lasers are of two types. Soft lasers are essentially an aid to healing, with relatively few rigorous studies available to support their use. Surgical hard lasers, however, can cut both hard and soft tissues, replacing the scalpel and drill in many areas. After initial experiments with the ruby laser, most clinicians have been using argon, carbon dioxide, and now Nd:YAG systems. The first dental laser based on a Nd:YAG engine provides handpieces of similar size to conventional instrumentation, and being fed by a fibre-optic "cable," has the flexibility for intra-oral use that the carbon dioxide lasers, widely used in oral surgery, lack. Furthermore, extensive clinical investigation has demonstrated their safety in clinical practice, and the fact that procedures can usually be performed without a local anaesthetic is obviously seen as an advantage by patients. Sterilizing as it cuts, the Nd:YAG laser promises to find uses not only in caries removal and soft tissue surgery but also in periodontics and endodontics.