The effect of plasma on transverse strength, surface roughness and Candida adhesion of two types of acrylic denture base materials (Heat cure and light cure)


Background: Dental polymers have a great use in dental applications such as denture, temporary crowns….etc; thisis due to their superior physical and chemical characteristics. At the same time some of these properties impose alimitation on applications in several new and high technology areas. Plasma treatment is one of the most widely usedsurface treatment techniques in which the composition and structure of a few molecular layers at or near thesurface of the polymer are modified. The aims of this study were to evaluate the effect of plasma treatment by argongas on transverse strength; surface roughness and Candida adherence to heat cure and light cure acrylic denturebase materials. Also compare the effect of plasma treatment on heat and light cure denture base materials.Materials and methods: A total number of 180 specimens were prepared in this study; they were divided into twomain groups according to the type of the material used (heat cure acrylic resin and light cure acrylic resin). Eachmain group was subdivided into three subdivisions according to the type of the test used (transverse strength,surface roughness and Candida adherence), for each test 30 samples were divided into three groups according tothe time of plasma treatment that were applied (control, 5 and 10 minutes). Plasma treatment process wasperformed for all the studied groups in two different periods (5 and 10 minutes) except for control group no plasmatreatment were performed.Results: Plasma treatment of heat cured acrylic specimens revealed a decrease in the transverse strength of thestudied groups for 5 and 10 minutes. Similar results were obtained for light cure denture base material after treatmentwith argon gas plasma for the same periods of time used for heat cure. Plasma treatment of heat cure and light cureacrylic specimens showed decrease in surface roughness and Candida adherence for (5min and 10min).Thecorrelation between surface roughness and Candida adherence in the present study showed a weak correlation forall tested groups for both types of materials except for 5 minutes plasma treated heat cure acrylic specimens whichwere moderate. Statistically, there was no significant difference between surface roughness and Candida adhesionfor all groups of both types of materials except for 5min group of heat cure acrylic specimens.Conclusion: Within the limitation of this study it can be concluded that argon plasma treatment to the surface ofheat and light cure denture base materials can cause a decrease in transverse strength, surface roughness andCandida adherence for 5 and 10min treatment times