sodium-hypochlorite and ethylene-dimethacrylate

To evaluate the effect of successive cycles of disinfection in different denture cleansers on the surface roughness and the Vickers hardness of two layers of acrylic resin (base-BL and enamel-EL) of two commercial cross-linked artificial teeth.. The occlusal surfaces of 60 acrylic resin denture posterior teeth (Trilux-TLX and SR Orthosit PE-SRO) embedded in autopolymerizing acrylic resin were ground fat with 1200-grit silicon carbide paper. Specimens were stored in distilled water at 37°C and then submitted to the microhardness (VHN) and roughness (μm) tests. Specimens were stored in distilled water at 37°C for 90 days and submitted to 720 disinfection cycles in sodium hypochlorite at 0.5%, 30% vinegar solution or distilled water (control). Afterward, micro-hardness and roughness tests were again performed. Data were analyzed using two-way ANOVA and Tukey's test (α=0.05).. Hypochlorite immersion decreased the hardness of BL and EL of SRO teeth, with an average reduction of 10.11% (p<0.008). TLX teeth demonstrated a hardness reduction of 28.96% of both layers for all solutions including water (p<0.0000). The roughness of both teeth was not affected by denture cleansers (p>0.37).. Hypochlorite promoted deleterious effects on the hardness of both layers of the artificial teeth tested. Immersion in vinegar and water also resulted in reduction of hardness of TLX teeth.. The surface hardness of the different layers of cross-linked artificial teeth can be altered by daily disinfection in denture cleansers commonly indicated for removable dentures.

Topics: Acetic Acid; Acrylic Resins; Carbon Compounds, Inorganic; Composite Resins; Dental Materials; Denture Cleansers; Disinfection; Hardness; Humans; Materials Testing; Methacrylates; Polymethyl Methacrylate; Polyurethanes; Silicon Compounds; Sodium Hypochlorite; Surface Properties; Temperature; Time Factors; Tooth, Artificial; Water

The aim of the study was to evaluate the effect of long-term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth.. Five acrylic resin denture teeth (Vipi Dent Plus-V, Trilux-T, Biolux-B, Postaris-P and Artiplus-A) and one composite resin denture teeth (SR-Orthosit-O) were embedded in heat-polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01).. Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p < 0.001). Immersion for 7 days in 4% chlorhexidine gluconate or distilled water had significant effect on the hardness of the acrylic resin denture teeth A (p < 0.01), and 1% sodium hypochlorite on teeth T (p < 0.01). All disinfection procedures decrease the hardness of the composite resin denture teeth (p < 0.01). Teeth O exhibited the highest and teeth V the lowest hardness values in the control group (p < 0.01).. Disinfection procedures changed the hardness of resin denture teeth.

Topics: Acrylic Resins; Chlorhexidine; Composite Resins; Dental Disinfectants; Dental Materials; Disinfection; Hardness; Humans; Materials Testing; Methacrylates; Microwaves; Polymethyl Methacrylate; Polyurethanes; Radiation Dosage; Sodium Hypochlorite; Sterilization; Temperature; Time Factors; Tooth, Artificial; Water

The aim of this investigation was to determine the effect of storage in disinfectants and artificial saliva on a series of commercial soft lining materials for dentures. Changes in mechanical properties and the nature of chemicals released into these solutions were studied.. Four soft lining materials were studied (Vertex Soft® and Villacryl Soft®, both of which are plasticized acrylics; Molloplast B® and Mollosil®, both of which are silicone elastomers). All were cured according to manufacturers' instructions, and then cylindrical specimens (6 mm height × 10 mm diameter) prepared. These were stored under various conditions then loaded in uniaxial compression and the stress measured at a strain corresponding to a 10% deformation to determine Young's modulus. Storage involved exposure either to the following disinfectants: 2% aqueous chlorhexidine gluconate, 2% aqueous sodium hypochlorite, Corega Tabs® cleansing tablets or 3% aqueous hydrogen peroxide; or to artificial saliva. For the latter, storage involved either immersion in artificial saliva at 37°C for the whole study, or immersion for 16h a day and dry at room temperature for the next 8h each day. GC/MS was used to determine species leached into these solutions.. The acrylic materials Villacryl Soft and Vertex Soft became less elastic on storage for up to 28 days whereas the silicone materials Molloplast B and Mollosil, showed no change in elastic properties. Various compounds were found to be released from these materials, including EGDMA, methyl methacrylate and dibutyl phthalate. Generally, the silicones were more stable than acrylics, releasing smaller amounts of the various eluants. In all cases, amounts eluted were well below permitted exposure limits.. Practical denture cleansing agents affect the properties of soft lining materials, reducing their elastomeric character, acrylics being more adversely affected than the silicones. These changes are associated with the loss of various chemicals, including plasticizers and monomers, from the soft lining materials.

Topics: Acrylic Resins; Chlorhexidine; Compressive Strength; Dental Disinfectants; Dental Stress Analysis; Denture Cleansers; Denture Liners; Dibutyl Phthalate; Drug Storage; Elastic Modulus; Hydrogen Peroxide; Materials Testing; Methacrylates; Methylmethacrylate; Saliva, Artificial; Silicone Elastomers; Sodium Hypochlorite