The use of lung function tests and sequential radiography appear to be suitable complementary methods of contrasting the effectiveness of obturator prostheses provided in the management of maxillectomy patients. The creation of an oral seal, demonstrable by normal subjects during swallowing and in the production of certain speech sounds, appears to be unobtainable in the management of maxillectomy. Effective obturation produces sufficient separation of the oral cavity from the nasal cavity to permit efficient swallowing and intelligible speech. These two methods also offer simple means to evaluate subjective experiences of the patient.