Abstract: A method and apparatus are provided for processing a hard material, for example a hard biological material such as dental enamel or bone, with optical radiation. A treatment zone of the material is selectively cleaned of ablation products and other dirt to enhance processing efficiency, and a tip through which the optical radiation is applied to the treatment zone of the hard material is spaced slightly from the treatment zone during at least a portion of the time that hydrating fluid is being applied to the zone and/or while air or another gas is applied to the zone to clean the surface thereof.