Effect of citrate addition and termocycling on water sorption, solubility and surface roughness of a soft liner

Abstract

Objective: Soft liners properties are changed when the material is in aqueous environment such as saliva, distilled water or denture cleansers. Some chemical compounds of the material suffer lixiviation process resulting on progressive increase of hardening, distortion and changes on surface roughness, which can compromise the materials’ longevity. Thus, this study was performed to evaluate and compare the water sorption, solubility and surface roughness a soft lining material (EversoftTM) on its original chemical composition and with addition of citrate (Experimental). Methods: Twenty specimens of each material, with measurements of 45 mm X 1 mm were polymerized and distributed into 4 groups (n = 10): EversoftTMwith sealing; G2): Eversoft- TM without sealing; G3): Experimental without sealing; e G4): Experimental with sealing. The specimens were stored in distilled water inside an oven at 37 oC, then submitted to thermocycling and evaluated at 4 different periods: T0 = 0 (control), T1 = 1000 cycles, T2 = 2000 cycles, T3 = 3000 cycles. Results: The addition of citrate on EversoftTM formula had an impact on all properties evaluated, however, after surface sealer appliance Eversoft presented better properties, and surface roughness and sorption of both groups did not differ statistically. EversoftsTM’ solubility values decreased significantly after sealer coating and were lower than the citrates’. Conclusion: When manipulated according to the manufacturer’s description, that is using the sealer, EversoftTM presented similar properties then the Experimental Group. Apparently, citrate adding did not replace the sealers function. Key words: Soft liner. Thermocycling. Water sorption. Solubility. Surface roughness.