Abstract The thoughts in this article may be summarized by stating that patients with dental caries are afflicted by a serious ailment. Their teeth are diseased and have carious lesions within them. When a carious lesion is excised, living tissues are cut. Excision of viable dentin is excision of extended living pulp. In order to treat patients with diseased teeth successfully, sound clinical judgment is required in addition to surgical skill. Sound clinical judgment dictates a sensible combination of old and new therapeutic practices for the patient's benefit. The dentist wants each patient to have the best treatment he can provide. The patient receives such treatment when the operation is carefully planned and executed within the broad framework of basic biomechanical principles from which all successful therapy derives. An operation so planned and conducted conserves the dental pulp, promotes patient welfare, and enhances the dentist's professional reputation.