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A model system has been developed to study the formation of plaque in natural, human, enamel fissures. Surgically removed, fully impacted third molars were used. The occlusal two-thirds of the crowns were separated from the teeth and sonicated. The specimens were then placed on a bridge or an acrylic appliance and exposed to the oral environment for 0, 1, 2, 3 and 5 d. The experimental fissures were then subjected to microbiologic and ultrastructural analysis. The results documented that fissure plaque could be conveniently sampled for subsequent microbiologic analysis using this technique. The microbiologic composition of developing fissure plaque was verified by ultrastructural data. [ABSTRACT FROM AUTHOR]

Three-dimensional photo-elasticity was used to study the stress distribution in complete dentures in functional positions. A new loading device was developed utilizing a linear motion bearing as its main component and mandibular dentures were evaluated for the first time. The stress concentrations were highest (2.5 fringes) on the working side of the mandibular denture. This was also demonstrated in the maxillary denture; however, the magnitude was less (1.8 fringes). The results indicate that this method could be used to quantitatively evaluate the effect of various occlusal schemes upon the denture bases. [ABSTRACT FROM AUTHOR]

The screw jack method has recently been introduced as a new approach to assessing the occlusal height in edentulous patients. Its use is psycho-physical in nature, and is supposed to rely on neurophysiological mechanisms. Its accuracy has been tested, and it was found to be sensitive to two factors; (i) interactions between dentist and patient, and (ii) to time. More clinical and neurophysiological research is required to refine the method, before it can be expected to replace generally accepted methods. [ABSTRACT FROM AUTHOR]