Effects of occlusal forms on pressure and bending during mastication with complete dentures.

The amount of strain in functioning dentures (and the resultant tissue distortion) caused by using various posterior teeth of different occlusal configurations has not been satisfactorily investigated. In an attempt to determine which occlusal form produces the greater overall strain and the greater strain per unit pressure applied, interchangeable posterior teeth (zero degree and anatomic) a were adapted to the same maxillary and mandibular cast metal denture bases to keep all denture-related factors constant, except for changes in the occlusal patterns. A diaphragm pressure transducer, calibrated hydrostatically, was mounted in the cast gold base of the mandibular denture under the first molar on the side preferred by the participant for chewing, the diaphragm of the transducer being fitted so that it was flush with the tissue surface of the denture. Pairs of strain gauges" were mounted on the lingual and buccal flanges of the mandibular denture and on the buccal flange of the maxillary denture on the participant's preferred chewing side. Each pair of gauges was mounted in the area of the first molar and oriented so that the longitudinal strain along the denture axis was measured directly. The second gauge measured strain at an angle of 900 to the first and was called the vertical strain even though the plane defined by the face of the denture to which the gauges were attached was not a true vertical plane. All wires were embedded in the denture bases and exited between the central incisors to avoid interfering with function. The participant masticated for a total of 80 sequences; 40 with zero degree teeth and 40 with anatomic teeth. The sequences with each tooth form were separated equally between the test