Evaluation of the effect of denture adhesives on surface roughness of two chemically different denture base resins

ABSTRACT Objective: To evaluate the effect of four commercially available denture adhesives (DAs) on surface roughness of two chemically different denture base materials. Materials and Methods: Fifty specimens of heat-cured polymethyl methacrylate, and another fifty specimens of light-cured urethane dimethacrylate were divided into five groups (n = 10), each was immersed in four prepared DAs (Corega Super Cream, Corega Ultra Powder, Olivafix Cream, Protefix Cream) as well as distilled water (control group). The mean surface roughness (R a) of the polished and unpolished surfaces of the specimens was recorded using profilometer device. T-test for paired observation was used to indicate any changes in surface roughness between the baseline and after 30 days of immersion in the DA. Results: Almost all the tested DAs had no significant effect on the roughness of polished and unpolished surfaces of both denture base materials. The Corega super cream DA produced significant increase in the roughness of the polished surfaces of both types of acrylic specimens (P < 0.05). Conclusion: The majority of the investigated DAs appears not to affect the surface roughness of denture base materials. Only Corega super cream DA produced detectable increase in the roughness of polished surfaces of denture base specimens.

Training Laboratories in Developmental Psychology

This is a description of a flexible program to train graduate and advanced undergraduate students in research in developmental psychology. Stress is on observational training and experiments which exemplify current theoretical issues and techniques, using newborns through eighth graders. Sample courses are outlined and include observation of an infant in his own home; paired-observation projects for observer-reliability training; three or four experiments (from, e.g., Piaget, Bandura, Bruner); paper-design of an original experiment; class demonstrations with visiting children of various scales of development; visits to and from area researchers; movies. Student response is exceptionally favorable.