study of clasp designs for asymmetric distal extension partial dentures

The clasp design in distal extension removable partial dentures [RPD] plays an important role in the distribution of load between the abutment teeth and the edentulous ridge. This study was assigned to evaluate clinically and radiographically the effect of the Budtz-Jorgensen and Bochet, Equipoise and RPA clasp designs in mandibular distal extension RPD on the abutment teeth supporting structures. Fifteen partially edentulous patients [asymmetric Kennedy class I] were divided into three groups [five each]. Each group received RPD with one of the three clasps. The Plaque Index, Gingival Index, attachment loss, bone height and tooth mobility were recorded at denture insertion and after 3,6,9 and 12 months. The Budtz-Jorgensen and Bochet clasp showed no change in the supporting structures throughout the 12 months. The Equipoise clasp and the RPA clasp showed significant Plaque accumulation and gingival inflammation after 9 and 12 months. In addition, the RPA clasp showed a significant increase in attachment loss and alveolar bone loss after 12 months. However, there was no tooth mobility in the three groups throughout the follow-up period

Cephalometric evaluation of artificial occlusal plane of complete dentures

An investigation was conducted to study the relationship and the angulation of the artificial occlusal plane as related to the maxillary plane, Cook's plane, Frankfort horizontal plane and the cephalometric occlusal plane. Twenty completely edentulous patients were selected for this study. Lateral cephalometric radiograph was taken for each patient and the cephalometric films were traced. The result obtained indicated that the cephalometric occlusal plane determined by the quadrilateral analysis was the only plane which tends to be parallel with the artificial occlusal plane. The statistical analysis showed that there was no significant correlation between the artificial occlusal Cook's plane angle and the artificial occlusal-Frankfort horizontal plane angle

Bond strength and candidal growth inhibition of the VLC soft liners in comparison to silicone and acrylic soft liners

The purpose of the present work was to compare bonding of the visible light-curved VLC soft liners to denture base resin with that of silicone and acrylic soft liners to denture base resin. Another purpose to study the effect of the studied soft lining materials on Candida albicans growth. Specimens were prepared from denture base resin bonded to the different denture soft liners. An Instron universal testing machine was used to measure the tensile failure of the different specimens. Other specimens from the different materials were prepared and were cultured with isolated Candida albicans. The percentage of growth inhibition of Candida albicans was compared. The results showed that the heat-cured silicone soft liner had the highest bonding values to denture base resin, followed by the two tested VLC soft liners. It was also shown that the self-cured acrylic soft liner had the highest inhibition values of Candida albicans growth while the silicone material had the lowest inhibition values of Candida albicans growth

Acrylic Denture base resins reinforced with glass fibers

This investigation was carried out to study the effect of incorporating different percentages of glass fibers on transverse strength, modulus of elasticity, deflection, and toughness of heat-cured and autopolymerizing acrylic denture base materials. Different percentages of loose, random and short cut glass fibers [0%,1%,2%,3%,5% and 10%] were incorporated into acrylic denture base resins. The results showed that the incorporation of 1% of glass fibers into the heat-cured acrylic resin increased transverse strength by some 31 percent. While the addition of 2% of glass fibers increased the transverse strength of the autopolymerizing acrylic resin by some 40 percent. The incorporation of more than 3% glass fibers into both types of acrylic resin had no significant effects on the transverse strength, modulus of elasticity, defection and toughness of both tasted materials [p>0.05]. The glass fibers had better effects on autopolymerizing acrylic resin rather than on heat-cured acrylic resin

Microwave disinfection of some acrylic denture base materials

The purpose of this study was to evaluate the disinfection of self and heat cured acrylic resins after the exposure to the microwave for different periods of time. The effect of microwave disinfection on transverse strength, modulus of elasticity and surface roughness of acrylic denture base resins was investigated. The results showed nonsignificant differences between transverse strength and modulus of elasticity of both tested materials upon the exposure to microwave for different periods of time. The self cured denture base material showed greater surface roughness than heat cured acrylic resin