Abstract: The present invention provides for a lip and cheek expander and tongue retractor for mechanically holding open a patient's mouth and stabilizing his tongue therein so as to facilitate dental and medical procedures. The present expander-retractor comprises first and second arc-shaped shells, each of said shells having a trough-shaped cross-section including first and second side walls; and a spring element having two ends, one of each of said ends secured to the first and second shells respectively, said element disposed in a plane which is substantially transverse to those planes defined by said side walls and which, upon insertion is substantially co-planer with the plane of the patient's tongue. The spring element includes a lingual arch which is adapted for engagement with the paient's tongue.