ABSTRACT
Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. Aims: This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. Settings and Design: This was a comparative in vitro study. Subjects and Methods: The materials included two silicone elastomers – A-2186 and Cosmesil M511 (Factor II Incorporated) – functional intrinsic red pigment and three disinfectants – Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Statistical Analysis Used: Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Results: Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. Conclusions: The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.
ABSTRACT
Pyogenic granuloma of the eyes usually occurs after ocular surgery or inflammation related to the eyes, itself. This lesion is commonly related to procedures associated with chalazia, strabismus, or even enucleation. However, the incidence of pyogenic granuloma that arises directly from the lower canaliculi of the nasolacrimal system is rare and not being extensively reported. We report a case of an elderly lady who presented with pyogenic granuloma post EDCR with silicone stenting for left nasolacrimal duct obstruction. She presented with persistent left eye epiphora following procedure. The unusual site for pyogenic granuloma and it occurrence after EDCR raise the possibility that the condition is related to previous procedure and the material being used.
Subject(s)
Granuloma, PyogenicABSTRACT
Introduction: Implant-supported extra-oral prostheses often require a retentive matrix to hold gold alloy clips and magnets, which act as retentive means. Silicone elastomers have a different structure to acrylic resins. Hence, primers are used to increase the bonding between silicone and acrylic resin. Aim of Study: To investigate the effect of new platinum primers on the peel bond strength of silicone elastomer to acrylic resins. Materials and Methods: Peel bond strength of Cosmesil 2004 to two acrylic resins was assessed using two primers (MED6-161 and MED160) and no primer (control group). Sixty samples were prepared and divided into six groups according to the combination of acrylic resin, silicone, primer and no primer. All samples were then exposed to load in a universal testing machine with a cross head speed of 25 mm/min until failure. Data was analysed using STATA 12.1 software. Values of mean peel force between light and auto-polymerising acrylic resins were compared using two-way ANOVA and tukey HSD test. Results: The interaction between primers and acrylic resins had a significant effect on peel bond strength between Cosmesil 2004 and acrylic resins. MED6-161 primer significantly improved peel bond strength of Cosmesil 2004 to light-polymerising acrylic resin. However, MED-160 primer enhanced peel bond strength between Cosmesil 2004 and auto-polymerising acrylic resin. Conclusion: The combination of primer and acrylic is important in improving the bond strength. However, further investigation of different primers, silicones and different surface treatments to achieve the optimum bonding is need.
ABSTRACT
PURPOSE: The aim of the study was to evaluate the effect of 3 silicone primers and 3 surface characterization of acrylic resin surface on bond strength between silicone elastomer and acrylic resin. MATERIALS AND METHODS: 96 Cosmesil silicones bonded to heat-curing acrylic resin were fabricated with the dimension of 75 x 10 x 3 mm. The 3 primers used in this study were G611 platinum primer, A-330 Gold platinum primer, and cyanoacrylates resin. Specimens without primer were used as control. The 3 types of surface characterization done were retentive holes with 1.5 mm in diameter and 0.5 mm deep, retentive beads of 0.6 mm diameter and the third type which was plain without any characterization. The specimens were then checked for bond strength by subjecting them to 180degrees peel test on a universal testing machine. The obtained results were then subjected to statistical analysis using 2-way ANOVA and Scheffe multiple post hoc procedures. The statistical significance was set at 5% level of significance. RESULTS: The maximum bond strength was seen for samples in which A-330G primer was used followed by G611 primer. The control group showed the minimum bond strength. Surface characterization of retentive holes increased the bond strength considerably as compared to retentive beads and samples without any surface characterization. CONCLUSION: Within the limitations of the study, A-330G primer was more compatible with Cosmesil M511 silicone and has better bonding of Cosmesil to acrylic resin. Retentive holes made on acrylic surface increased the bond strength considerably than those without any surface characterization.
Subject(s)
Collodion , Cyanoacrylates , Platinum , Silicone ElastomersABSTRACT
Current materials used for maxillofacial prostheses are far from ideal,and how to develop a final prosthetics material is a significant topic in the research of maxillofacial prostheses.In this paper,some pertinent research of silicone elastomeric materials,such as mechanical properties and colorant are reviewed.
ABSTRACT
Objective:To evaluate the effects of primers on the bonding of an silicone elastomer to acrylic resin.Methods:Acrylic resin specimens were divided into eight groups.Six new primers and Cosmesil G611 primer were applied to the acrylic resin surfaces respectively.Untreated group was used as control.The shear bond strengths between silicone elastomer and acrylic resin were determined.D primer were measured by Forier transform infrared spectroscopy,and the bands were analyzed using spectrum method.Results:The experiment group with different concentration of ?-MPS showed different shear bond strengths between silicone elastomer and acrylic resin.Type D primer showed 2.20 MPa shear bond strength,which was significantly higher than that of other groups.While 1.44 MPa for Cosmesil G611 primer was found,there was no bond strength for untreated group.Conclusion:The concentration of ?-MPS is relative to the shear bond strength and type D primer can give the highest shear bond strength.
ABSTRACT
Objective:Through monitoring the pH of the growth medium,to evaluate the growth and/or acid production ability of Candida albicans on silicon elastomer incorporated with two different antifungal agents.Methods:Antifungal agents(AntimTM-AM and Conval pag-40)were added at concentrations from 0% to 2%,and antibacterial effect of the material in saliva and serum groups were examined.The third group added nothing was served as the control.Results:Each group with 2% antifungal agents showed great inhibitory effects on the acid production and /or the growth of C.albicans.These inhibitory effects consisted of a delay in the onset of rapid pH decline,decreased with the rate of pH change and increased in minimum pH.As a result,Conval pag-40 showed a significantly greater antimicrobial effect than AntimTM-AM.Conclusion:Silicone elastomer material incorporated with antifungal agents have strong antibacterial ability and can satisfy the requirements of clinical application.
ABSTRACT
Objective:To evaluate the effects of pigment concentration on spectral reflectance of pigmented silicone elastomer.Methods: Six kinds of pigment at different concentrations was respectively added into MDX-4-4210 silicone elastomer to prepare six series of single-chroma-samples, including red, yellow, blue, brown, white and black.The pigment concentrations to base elastomer were set at 0.1, 0.2 , 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9 and 1.0C, respectively while other conditions were kept the same. C is the maximum pigment concentration in practical use. The target samples were also prepared. By spectrophotometer, the spectral data of the single-chroma-samples and target samples were measured.Results:With the increase of pigment concentration, the spectral reflectance of the six series of single-chroma-samples and target samples decreased.Conclusion:Increase of pigment concentration may result in decrease of spectral reflectance of single-chroma-samples and taget samples.
ABSTRACT
Objactive:To study the color changes of SY-1 silicone elastomer before and after polymerization.Methods:L*a*b*color parameters of 10 samples of SY-1 silicone elastomer were measured with Minolta chroma-ticity instrument(CS-321) before and after polymerization.The color difference(△E) between precure and post-cure was calculated as△E =[(△L)2+(△a)2+(△b)2]1/2.Results:After polymerization L*and a*valueswere increased(P
ABSTRACT
砄bjective:To compare the adherent ability of Candida albicans on the surface of two kinds of silicone elastomer used as prosthodontic materials and to study the factors affecting the adherence.Methods: Candida albicans were cultured on the surface of SY 1 and MDXA 4210 with or without saliva acquired pellicle for 10 min, then the number of the bacteria was counted.Results:With or without saliva acquired pellicle,the number (1?10 3/mm 2) of C.albicans on SY 1 was 24.5?0.88 and 2.0?0.47 respectively( P 0.05 ).Conclusion:There is little difference between the adherent ability of C.albicans on the two kind of silicone elastomer.Saliva acquired pellicle can decrease the adherence.
ABSTRACT
Objective:To evaluate the effects of surface modified nano titanium-oxide on the mechanical properties of A-2186 silicone elastomers. Methods:Added surface modified nano titanium-oxide into A-2186 silicone elastomers with 0.0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0% additions according to the ASTM standard. The mechanical properties of A-2186 silicone elastomer including the tensile strength, the broken elongation, the tear strength and the Shore-A hardness were tested separately. The section of samples were investigated by scanning electron microscope and energy spectrum analysis. Used statistics method to analyse the results. The results were analysed with software EPSS 13.0. Results:With the addition of nano titanium-oxide increasing, the tensile strength, the broken elongation and the tear strength of A-2186 silicone elastomers increased firstly, and then decreased. While the Shore-A hardness of A-2186 silicone elastomers increased gradually. When the addition of surface modified nano titanium-oxide reached to 2.0%, the nano titanium-oxide dispersed well in the base without agglomeration. Under such condition, the A-2186 silicone elastomer showed the best general mechanical properties:the tensile strength was (6.54?0.55) MPa, the broken elongation was 618.00?7.58(%), the tear strength was (16.64?0.52) kN/m and the Shore-A hardness was (31.00?0.79) U. Conclusion:The mechanical properties of A-2186 silicone elastomers are improved most greatly with 2.0% addition of surface modified nano titanium-oxide to the base of A-2186 silicone elastomers.