Orally inserted medical device includes a pair of laterally separated upright barriers downwardly abuttably restable along the two lower rows of dental molars supported by the parallel alveolar ridges of the mandible. The physician inserts two index fingers or thumbs into and thus protected by the orally positioned medical device ancillary to manually reducing dislocated mandible. The device barrier components adequately resist uprightly extending dental forces and include semi-hard material at the teeth exposed surfaces, and the device is so constructed as to permit ready accurate insertion into, procedural use within, and removal from, the patient's oral cavity.