The flange technique is a denture-making method designed to improve retention and stability and features the use of oral functional motions in making dentures. What features in articulation so called functionally formed dentures (FFD) have has not yet been clarified. Therefore, manually formed dentures (MFD) based on conventional anatomical landmarks have been made and compared with FFDs on articulation. Articulation tests were made for five weeks after placing the two dentures in subjects. The results were as follows : 1. With a FFD on, confused syllables tended to be found in bilabial and alveolar sounds. 2. With a MFD on, confused syllables tended to be found in bilabial, alveolar, and dental sounds. 3. Confused bilabial and alveolar sounds tended to be confused with each other. 4. Analysis of confused syllables on a sound spectrograph indicated clear differences in preceding consonants and transition phases in comparison with those normally enounced. 5. All monosyllables were enounced clearly from the second to the third week after placing the denture for both MFDs and FFDs. 6. Articulation disorders tended to occur when thickness of the polished surface was as follows : 3mm or more for the floor anterior to modiolus, 6mm or more for the floor posterior to it, and 3mm or more for the mandibular lingual floor.
