Heat-cured Denture Base Resin Research Articles

Adhesion of Denture Characterizing Composites to Heat-Cured, CAD/CAM and 3D Printed Denture Base Resins.

To measure the adhesion of the denture characterizing composite to heat-cured, CAD/CAM and 3D printed denture base resins. Two different denture characterizing composites with different viscosities (SR Nexco; high viscosity (SR) and Kulzer Cre-active; low viscosity (K)) and three denture base resins (Heat cure, CAD-milled and 3D printed) were investigated. 60 beams (25 × 4 × 3 mm) were fabricated for each denture base resin; 30 were bonded to SR and 30 to K to form a beam 50 × 4 × 3 mm. These were further divided (n = 10/group) to simulate the effects of 0, 6, and 12 months intraorally via thermocycling. The beams were subjected to a 4-point bend test using the chevron-notched beam method. Fracture toughness K1C (MPa ·m1/2 ) and flexural bond strength (MPa) were calculated. All specimens were analyzed for the mode of failure under the light microscope and selected specimens under scanning electron microscope. Results were statistically analyzed using ANOVA (SPSS Ver 25). The mean K1C was highest for the SR composite bonded to the heat-cured denture resin group (0.28 ± 0.11), followed by CAD/CAM (0.18 ± 0.04) and 3D printed groups (0.23 ± 0.16). Differences were not statistically significant (p = 0.268). Within each group, aging showed no statistical significance between the mean K1C and flexural bond strength (p = 0.209). The mean K1C for the K composites bonded to the three different denture bases were significantly lower compared to the SR group (p < 0.001). The mean K1C for the heat-cured denture resin group was (0.21 ± 0.1), followed by CAD/CAM (0.13 ± 0.04) and 3D printed groups (0.03 ± 0.02). Within each of the K group, aging showed a statistical significance for both the mean K1C and flexural bond strength (p = 0.002). The high viscosity SR showed significantly higher K1C and flexural bond strength to the lower viscosity K when bonded to heat-cured, CAD-milled and 3D printed denture base resins. Heat-cured denture base resins produced the highest K1C and flexural bond strength when bonded to two different types of characterizing composites.

Effect of novel cycloaliphatic comonomer on the flexural and impact strength of heat-cure denture base resin.

This study aims to evaluate the impact of adding a novel tricyclodecane dimethanol diacrylate comonomer on the flexural strength (FS) and impact strength (IS) of heat-cure denture base resin at 10% and 20% (v/v) concentrations. To test the FS and IS, a sum total of 150 bar-shaped specimens were prepared according to standard specifications. For the FS, the specimens were subjected to the three-point bend test with a span length of 50 mm. For the IS, Charpy's test was executed with a span length of 60 mm. The FS was measured in MPa, and the IS was measured in kJ/m2. There was a statistically significant difference (P < 0.001) between the control and experimental groups in that both the FS and IS were increased in the experimental groups relative to the control group.

Evaluation of some properties of recycled polymethylmethacrylate incorporated to the acrylic resin

Many attempts have been made enhancing properties of PMMA denture base material. Adding fillers to PMMA was a commonly used method to improve physical and mechanical properties. To estimate the effects of incorporating recycled polymethylmethacrylate with a different percentage with conventional heat-cured acrylic resin on some properties of heat-cured denture base resin. The recycled polymethylmethacrylate (Chaini-HK G) particles dissolved at (5%,10%,15%) was added to heat-cured polymethylmethacrylate (Spofadental, Czech Republic) polymer and mixed with a ratio of 2:1 with the polymethylmethacrylate monomer. A total number of specimens were 80, which divided into three experimental groups (5%, 10%, 15%) and control group. Each group have 20specimens. The surface hardness, water sorption, solubility and residual monomer of test groups measured as well as compared to that of control groups. Fourier transform infrared spectroscopy test (FTIR) was done for three experimental and control group. This study shows a statistically significant difference at (p&lt;0.01) in the hardness of recycled polymethylmethacrylate incorporate material (10 %,15%) groups when compared with a control group; while recycled polymethylmethacrylate incorporated (5%) group show no significant difference, group with 15% shows the highest Vickers hardness value. The mean values of water sorption test solubility test and residual monomer were decreased with the increase of incorporating a percentage of recycled polymethylmethacrylate as compared to the mean value of the control group. The incorporation of recycled polymethylmethacrylate to heat acrylic resin at different percentage improves some of its properties.

Mechanical properties of a polymethyl methacrylate block for CAD/CAM dentures.

This study compared the mechanical properties and molecular distribution of a polymethyl methacrylate (PMMA) block (Dry) with specimens that were fabricated by a conventional method and cured in a wet environment (Control). Two specimen types were fabricated with heat-curing denture base resin. Dry specimens were polymerized at high pressure and in a dry system, while Control specimens were polymerized with a heat-curing method, in accordance with the manufacturer's recommended procedures. Specimens from each group were evaluated for three-point bending, water sorption and solubility, and color change, and by gel permeation chromatography (GPC). Mean values for the flexural strengths and moduli of the Dry specimens were significantly higher than those of the Control specimens (P > 0.05). Water sorption and discoloration values of the Dry group were significantly lower than those of the Control group. Mean weight-average molecular weights of the Dry group were higher than those of the Control group. As compared with the conventional method, the present method of fabricating PMMA blocks under high pressure yields superior mechanical properties for the denture base.

Effect of silver nanoparticles incorporation on microhardness of Heat-cure denture base resins

Background: Poly (Methyl methacrylic acid) based materials are widely used for the fabrication of removable complete and partial denture prosthesis. Regular cleansing of these dentures may abrade the surface due to an inherent lack of adequate surface hardness. This roughness may adhere food to the denture surface, making it dirty and further cause stomatitis. Recently, antimicrobial activity of denture base materials incorporated with silver nanoparticles was studied, that may logically prevent microbial growth on the denture. However, the effect of these nanoparticles on the mechanical properties, which provide longevity to the prosthesis, was not substantiated. Aim: This study was designed to evaluate the effect of incorporating various concentrations of silver nanoparticles into heat-cure denture base resin materials, on their surface hardness. Materials and methods: Silver nanoparticles were incorporated at various concentrations (0.5, 1.0, 2.0 and 5.0 wt%) into three different heat-cure denture base materials. A total of 150 rectangular-shaped specimens (62 x 10 x 2.5), which comprises 50 samples from each of the three heat-cure acrylic resins were made using the compression moulding technique. Ten specimens (n=10) were allocated for each concentration such as control, 0.5wt%, 1.0wt%, 2.0wt% and 5.0wt% concentrations of silver nanoparticles. The microhardness was evaluated using the Vickers micro-hardness tester. The data were subjected to One way ANOVA and Tukey HSD tests for statistical analyses. Results: Significant differences (p=0.000) were observed between the unmodified and modified denture base materials. Conclusion: Silver nanoparticles can be considered as the favourable additives to increase the surface hardness of denture base materials.

An In Vitro Assessment of Physicomechanical Properties of Heat-cured Denture Base Resin Disinfected by Ozonized Water

An In Vitro Assessment of Physicomechanical Properties of Heat-cured Denture Base Resin Disinfected by Ozonized Water

Effect of Novel Cycloaliphatic Comonomer on Surface Roughness and Surface Hardness of Heat-cure Denture Base Resin.

ABSTRACTBackground:Polymethyl methacrylate (PMMA) is a widely used resin in the field of prosthodontics for fabricating myriad orofacial prostheses. Albeit several advantages, it possesses certain lacunae concerning physicomechanical properties.Purpose:This in vitro research aimed to evaluate the surface roughness (SR) and hardness (SH) of heat-cured PMMA processed with a cycloaliphatic monomer, tricyclodecane dimethanol diacrylate (TCDDMDA), in methyl methacrylate at various concentrations.Materials and Methods:Groups have been divided into control (SRC and SHC) and experimental groups (SR10 and 20; SH10 and 20). Forty-five PMMA disc specimens were prepared. SR was assessed using a nanomechanical testing machine and the arithmetic roughness (Ra) was recorded. The same specimens were then subjected to Vicker’s microhardness testing and Vicker’s hardness number (VHN) was obtained. Data were compared using one-way analysis of variance (ANOVA) and post hoc Bonferroni tests (α=0.05).Results:The mean (standard deviation [SD]) of SRC, SR10, and 20 groups were 111.415 nm (0.789), 62.666 nm (0.482), and 41.004 nm (0.561), respectively. The mean (SD) VHN of SHC, SH10, and 20 groups were 21.003 (0.252), 23.975 (0.207), and 34.622 (0.079), respectively.Conclusion:The addition of TCDDMDA markedly decreased the SR and increased the SH of the experimental groups.

Comparative Evaluation of the Flexural Strength of Heat Polymerized Acrylic Resin with the Addition of 8% and 13% Aluminum Oxide Powder: An In-vitro Study

Introduction: Acrylic resins have been used successfully as denture bases. However, acrylic resin denture base materials are brittle and have poor strength and thermal conductivity. Therefore, it is essential to improve the flexural strength of heat polymerized acrylic resin. The present study aimed to evaluate and compare the flexural strength of heated polymerized acrylic resin with the addition of 8% and 13% aluminum oxide powder. Methods: In total, 90 acrylic specimens were fabricated and divided into three groups of A1 (unmodified heat-cured denture base resin), A2 and A3 (heat-cured denture base resin polymer modified with 8% and 13% by weight of aluminum oxide powder, respectively). The specimens were stored in distilled water for one week, and flexural strength was assessed using a universal testing machine. Data analysis was performed using one-way analysis of variance (ANOVA). Results: Comparison of groups A1 and A2 (8%) showed the highest flexural strength (85.94 MPa) in group A2. A significant increase was observed in the values of flexural strength with 13% alumina addition. Comparison of groups A1 and A3 (13%) showed the highest flexural strength (86.41 MPa) in group A3, and the difference in the mean values of flexural strength was considered significant. Moreover, comparison of groups A2 and A3 indicated the highest flexural strength in group A3. Conclusion: Addition of alumina to conventional heat-cured acrylic resin shows increase in flexural strength. Increasing the flexural strength of acrylic resin base materials could results in higher clinical success rate.

Effect of adding aluminum oxide on the flexural strength of heat-cured poly (methyl methacrylate) denture base resin

Background: Apart from its numerous advantages, poly (methyl methacrylate) (PMMA) has certain limitations such as its low strength, brittle on impact, poor thermal conductivity, and resultant low flexural strength. This study is, therefore, planned to investigate the flexural strength of heat-cured PMMA denture base resin with the addition of different percentage of aluminum oxide powder. Materials and Methods: A total of 120 specimens of PMMA (DPI® Heat Cure) of standard dimension (64mm x 10mm x 2.5mm) as per the American Dental Association specification No. 12/International Standards Organization specification No. 1567 for the determination of flexural strength were prepared: 30 for each of the four study groups. Aluminum oxide powder was added in specific percentage (5%, 15%, and 25% by weight) to the polymer component of heat-cure denture base resin as per the different subgroups. Results: The results of this study showed that the highest mean flexural strength was for specimens in Subgroup A, i.e., PMMA reinforced with 5% aluminum oxide powder by weight, with a mean value of 124.39 Mpa. Conclusions: Among the experimental group, the highest mean flexural strength of 124.39 Mpa was found with Subgroup A (5%) followed by Subgroup B (15%) which was 116.83 Mpa. The least flexural strength of 95.81 Mpa was found with Subgroup C (25%).

Impact Strength and Dimensional Accuracy of Heat-Cure Denture Base Resin Reinforced With ZrO2 Nanoparticles: An In Vitro Study.

Background:Polymerization shrinkage and fracture are the two common trouble shoots with denture base resins. Polymerization shrinkage affects the dimensional accuracy and fit of the prosthesis. The effect of zirconia (ZrO2) nanoparticles on polymerization shrinkage is not documented yet.Purpose:The aim and objective of this study were to evaluate the impact strength and dimensional accuracy of heat-cured poly methyl methacrylate (PMMA) on reinforcement with ZrO2 nanoparticles.Materials and Methods:Conventional heat-cure denture base resin (control) and the polymer reinforced with 3, 5, and 7 wt% of ZrO2 nanoparticles were prepared and used in this study. Forty bar-shaped specimens were prepared and tested for impact strength using Charpy’s type impact tester. Forty denture bases were fabricated and checked for dimensional accuracy by measuring the distance between the denture base and the cast in two different sections using the travelling microscope.Results:The impact strength decreased with increased concentration of ZrO2 and found to be least at 7 wt% concentration (2.01 ± 0.26 J/mm2). The distance between the denture base and the cast significantly decreased both in the posterior palatal seal region (0.060 ± 0.007 cm) and mid-palatine section region (0.057 ± 0.006 cm) with ZrO2 nanoparticles reinforcement and was found to be least at 7 wt% concentration.Conclusion:Reinforcement of heat-cured PMMA with ZrO2 nanoparticles significantly increased the dimensional accuracy and decreased the impact strength.

Synthesis of zirconia, organic and hybrid nanofibers for reinforcement of polymethyl methacrylate denture base: evaluation of flexural strength and modulus, fracture toughness and impact strength

Objective The objective of this study was to synthesize and characterize inorganic zirconium oxide (ZrO2), organic [bisphenol A diglycidyl ether dimethacrylate (Bis-GMA)+triethylene glycol dimethacrylate (TEGDMA)+polyethylene glycol dimethacrylate (PEGDMA)] and hybrid (ZrO2+ Bis-GMA + TEGDMA) nanofibers and the use of these nanofibers for improving flexural strength (FS) and flexural modulus (FM), fracture toughness (FT) and impact strength (IS) of polymethyl methacrylate (PMMA) resin. Materials and methods Inorganic, organic and hybrid nanofibers were synthesized by wet electrospinning technique. The study was divided into four groups according to the type of added nanofibers (6%) to the heat-curing PMMA denture base resin; control group: PMMA without nanofibers, inorganic group: PMMA with silanized ZrO2 nanofibers, organic group: PMMA with Bis-GMA/TEGDMA/PEGDMA nanofibers and hybrid group: PMMA with ZrO2/Bis-GMA/TEGDMA nanofibers. According to ISO FDIS 20795-1:2013, three-point bending test was used to measure FS, FM and FT for each group (n = 10). According to ISO 197-A1: 2005, impact tester was used to measure IS for each group (n = 10). One-way analysis of variance was used for statistical significance between groups and post-hoc (Tukey's test) was used for multiple comparisons. P value less than or equal to 0.01 was considered significantly different. Results The synthesized pure forms of three types of nanofibers were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. Nanofibers-reinforced groups (ZrO2, hybrid and organic, respectively) recorded high means % than that of the control group as follows: 205, 184 and 170% for FS (MPa), 184, 149 and 120% for FM (GPa), 210, 189 and 177% for FT (MPa m1/2) and 151, 180 and 176% for IS (KJ/m2). In each of the four tested mechanical properties, one-way analysis of variance revealed a significant differences between the studied groups (P = 0.000) and post-hoc (Tukey's test) revealed that nanofibers-reinforced groups were markedly significantly higher than control group (P = 0.000). Conclusion ZrO2, Bis-GMA/TEGDMA/PTEGDMA and ZrO2/Bis-GM/TEGDMA hybrid nanofibers synthesized by electrospinning technique improved significantly FS, FM, FT and IS of PMMA resin (P = 000).

Comparison of Bond Strength of Acrylic, Composite, and Nanocomposite Artificial Teeth to Heat-Cure Acrylic Denture Base Resin.

Objectives:The present study aimed to evaluate the bond strength of heat-cure denture base resin to newly designed Iranian artificial acrylic teeth.Materials and Methods:In this in-vitro experimental study, shear bond strengths of Ivoclar acrylic, Apple composite, and B-Star nanocomposite teeth to heat-cure acrylic denture base resin were compared. A total of 18 samples were selected from each group of teeth. The samples were attached to heat-cure resin according to ISO 10477 standard. For the assessment of bond strength, the samples were placed in a universal testing machine and were subjected to shear forces at a speed of 1 mm/minute to record the fracture load. Descriptive statistics, including frequency, mean, and standard deviation, were calculated using SPSS 20 software. Two-way analysis of variance was used to compare the shear bond strength of the groups with and without monomers and the studied artificial teeth.Results:The mean shear bond strengths of Ivoclar acrylic teeth were 392.22±23.76 MPa and 337.11±32.18 MPa with and without adding monomers to the tooth surface, respectively. The mean shear bond strengths were 250.44±29.84 MPa and 238.33±27.28 MPa (without monomers) and 438.33±24.16 MPa and 311.56±32.78 MPa (with monomers) for Apple composite and B-Star nanocomposite artificial teeth, respectively.Conclusion:The greatest shear bond strength was attributed to Ivoclar acrylic teeth followed by Apple composite and B-Star nanocomposite artificial teeth. Addition of monomers to the tooth surface significantly strengthened the shear bonding of acrylic base resin to the teeth.

Evaluation of In Vitro Cytotoxicity of Heat-cure Denture Base Resin Processed with a Dual-reactive Cycloaliphatic Monomer

The aim of this study is to evaluate cytotoxicity of tricyclodecane dimethanol diacrylate (TCDDMDA) when added to conventional heat-cure methyl methacrylate (MMA) monomer at 10% and 20% (v/v) concentrations. Twenty seven disk-shaped processed specimens were divided into control group (n = 9; comprises specimens made without substituting TCDDMDA in MMA) and two experimental groups (n = 9 each; specimens prepared by substituting TCDDMDA in MMA at 10% and 20% (v/v) concentration). Eluates were prepared by placing three specimens of each group into 9 mL of culture medium and then incubated at 37ºC for 24 hours. Continuous cells lines of L929 mouse fibroblast cells were used and MTT assay was employed to assess cytotoxicity. One-way analysis of variance (ANOVA) with post hoc Tukey's honestly significant difference (HSD) test was used to compare the mean optical density (OD) values and cell viability among the groups. A statistically significant difference was obtained (p = 0.000) when the mean and standard deviation of OD and cell viability (%) of the groups were compared. Highest OD value and cell viability was obtained with E20 group followed by E10 group. Addition of TCDDMDA in MMA of heat-cure denture base resin has no cytotoxic effect on L929 mouse fibroblasts. Dual-reactive TCDDMDA is a crosslinking monomer which has no cytotoxic effects on mammalian cell cultures. Hence, incorporation of TCDDMDA to MMA can be extrapolated and projected for fabricating dentures without compromising biocompatibility. How to cite this article: Ranganthan A, Karthigeyan S, Murugesan SV, et al. Evaluation of In Vitro Cytotoxicity of Heat-cure Denture Base Resin Processed with a Dual-reactive Cycloaliphatic Monomer. J Contemp Dent Pract 2019;20(11):1279-1285.

Evaluation of the antimicrobial activity of heat-cure denture base resin materials incorporated with silver nanoparticles

Background: Poly (Methyl methacrylic acid) based materials are the most widely used for the fabrication of removable complete and partial dentures. Certain microorganisms adhere to the tissue surface of a denture base, especially on palatal region, often leading to Denture stomatitis. Numerous attempts were made to treat the denture stomatitis with various antifungal agents showing variable success rates. This may be attributed to the loss of the drug rapidly into the saliva, inhomogeneous distribution of the drug and the development of resistance to antifungal therapy. Aim: This study was done to evaluate the effect of incorporating various concentrations of silver nanoparticles on the antimicrobial activity of heat-cure denture base resin materials. Methods: Silver nanoparticles were incorporated at various concentrations (0.5, 1.0, 2.0 and 5.0 wt%) into three heat-cure denture base materials. A total of 300 disc-shaped specimens (10 × 2 mm) of heat-cure acrylic resin were made using compression molding technique which comprises 100 specimens with each denture base material. Fifty specimens from each denture base materials were allocated to each microorganism used in the study which comprises into five groups with ten specimens (n=10) for each concentration such as control, 0.5wt%, 1.0wt%, 2.0wt% and 5.0wt% concentrations of silver nanoparticles. Antimicrobial activity of control and modified specimens were evaluated using direct contact method against C albicans, and S Mutans by counting the number of colony-forming units. The data were subjected to One way ANOVA and Tukey HSD tests for statistical analyses. Results: Significant(P<0.05) differences were observed in the antimicrobial activity against C albicans and S Mutans between the control and modified groups of heat-cure denture base resin materials. Conclusion: Silver nanoparticles are the favourable materials to incorporate into denture base materials as they exhibit superior antimicrobial activity.

PG - 68: Evaluation of Shear Bond Strength Between three different Acrylic Teeth and Heat Cure Denture Base Resin due to the Effects of trimming the Ridge Lap Area - An In-Vitro Study

PG - 68: Evaluation of Shear Bond Strength Between three different Acrylic Teeth and Heat Cure Denture Base Resin due to the Effects of trimming the Ridge Lap Area - An In-Vitro Study

Efficacy of Various Pretreatments on the Bond Strength of Denture Teeth to Denture Base Resins.

This in vitro study evaluated the shear bond strength (SBS) of heat-cured denture base resin (PMMA) to acrylic resin teeth treated with different pretreatments, especially laser irradiation of different powers (1-4 W). The acrylic resin teeth were separated into seven groups (n = 10) for the following different pretreatments: control group (no surface treatment) (G1), grinding with a tungsten carbide bur (G2), sandblasting (G3), and erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation at 1 W, 2 W, 3 W, 4 W output powers in (G4-7), respectively. Test specimens were produced according to the PMMA manufacturers' instructions and were subjected to a SBS test at a crosshead speed of 1 mm/min until fracture. Debonded surfaces were evaluated by a stereomicroscope for the type of failure. SEM (scanning electron microscope) analyses were done to estimate the surface changes of the acrylic resin teeth. The data were submitted using a one-way ANOVA and post hoc Tukey-Kramer multiple comparison tests (p = 0.05). The highest bond strength was obtained in G3, and similar SBS values were considered in other groups, and no significant differences were found among the surface treatments and the control group (p < 0.05). All groups had a high percentage of adhesive failures. Laser irradiations promote surface topography alterations. However laser irradiation of the adhesive surface was found ineffective. The SBS of acrylic resin teeth to a PMMA denture base material is independent of the surface pretreatments Er,Cr:YSGG laser irradiation, sandblasting, and grinding with a carbide bur. All the surface treatments provided a similar bond between the acrylic denture base and the teeth.

An in vitro study to evaluate and compare the surface roughness in heat-cured denture-based resin and injection-molded resin system as affected by two commercially available denture cleansers.

Background:Denture hygiene is of utmost importance to maintain the dentures as well as the underlying tissues in appropriate health. Various denture cleansers as well as denture-based materials have evolved in the market; however, the effect of denture cleansers on different types of denture-based materials has not been very well documented.Aim:The purpose of this in vitro study was to evaluate and compare the surface roughness in heat-cured denture-based resin and injection-molded resin system as affected by two commercially available denture cleansers for a period of 15, 30, and 45 days.Methodology:A standardized metal die was fabricated to make 120 denture-based resin discs of uniform dimensions. The samples of heat-cured denture-based resin and injection-molded thermoplastic denture-based resin were immersed in the two denture cleansing solutions for a period of 15, 30, and 45 days, respectively. The surface roughness was evaluated by surface profilometer TR200. The data were subjected to statistical analysis and the comparison of quantitative data was done using unpaired t-test and repeated-measures ANOVA test.Results:The surface roughness values (Ra) of heat cured denture base resin samples when immersed in two denture cleansers were 0.22 μm at 0 days, 0.27 and 0.29 μm at 15 days, 0.29 and 0.31 μm at 30 days, 0.30 and 0.31 μm at 45 days whereas for injection moulded samples surface roughness values were 1.31 & 1.27 μm at 0 days, 1.46 & 1.66 μm at 15 days, 1.50 & 1.69 μm at 30 days, and 1.50 & 1.69 μm at 45 days.Conclusion:The surface roughness (Ra) increased significantly in injection-molded polyamide denture-based resin samples when immersed in both the denture cleansers. Whereas, heat-cured denture-based resin samples did not reveal any significant surface changes at the various time intervals. Hence, the use of denture cleansers is questionable in thermoplastic resins.

Physical Properties of Heat Cure Denture Base Resin after Incorporation of Methacrylic Acid.

Introduction:Heat cure acrylic resins are the most commonly used denture base materials. The important limitation is they may act as reservoir of microorganisms. The adherence of microorganisms can be reduced by chemical modification of the surface charge of denture base resin. Incorporation of methacrylic acid (MA) in the denture base resin gives a negative surface charge. A denture base having a negative surface charge may hinder the initial adhesion of microorganisms through repulsive electrostatic forces.Aims and Objectives:The present in vitro study was performed to determine the effect of addition of antimicrobial agent MA on the flexural strength and surface roughness of heat cure denture base resin.Materials and Methods:A total of 90 heat cure acrylic specimens were prepared. Of 90 specimens, 30 were prepared as Group I control group without addition of MA. Groups II and III specimens were prepared by adding 10% and 20% MA, respectively. Using universal testing machine and surface roughness tester, flexural strength and surface roughness of specimens measured.Results:In the present study, decrease in the flexural strength was observed when the concentration of the MA increased in the denture base resin. A slight increase in the surface roughness was observed as the concentration of MA increased.

Effect of Repeated Microwave Disinfection on the Surface Hardness of a Heat-Cured Denture Base Resin: An In vitro Study.

Statement of the Problem:Disinfection of complete dentures is very crucial to prevent cross-contamination and infection. Microwave disinfection is a quick, easy, and effective means to disinfect dentures. However, the effect of repeated microwave cycles on the surface hardness property of heat-cured polymethyl methacrylate (PMMA) resin is not known.Materials and Methods:A total of 60 samples of heat-cured PMMA resin were fabricated for surface hardness. Each group was divided into four groups, according to the number of microwave cycles (MWC) applied for disinfection: control group (no disinfection) 0MWC, 1MWC group, 3MWC group, and 5MWC group.Results:No significant change on the surface hardness of a heat-cured denture base resin on repeated microwave disinfection.Conclusion:The repeated microwave disinfection showed statistically nonsignificant change on the surface hardness of the PMMA resin. Microwave disinfection can be safely used in regular practice to avoid cross-contamination and can also be suggested to patients for the regular denture hygiene.

Evaluation of Destaining Property of Denture Cleansers on Heat-cured Denture Base Resins using Common Indian Food Stains

ABSTRACTAimTo compare the efficacy of two different denture cleansers in removing tea and paan stains from conventional and high-impact heat-cured denture base resins and also to find out the duration of contact required by the dentures with cleansers, for best results.Materials and methodsA total of 80 specimens (40 conventional and 40 high impact) were fabricated. The samples were stained with tea and paan solutions. Stained samples were subjected to immersion in denture cleansers, namely Dentural (sodium hypochlorite) and Fitty Dent (sodium perborate). Optical density values were measured using spectrophotometer at prestain, poststain, postcleansing 15 minutes, postcleansing 8 hours, and post cleansing brushing. The data were analyzed statistically.ResultsHigh-impact denture base resins stained more than the conventional denture base resin. Staining potential of paan solution was higher than that of tea solution. Dentural (sodium hypochlorite) is superior to Fitty Dent (sodium perborate) in the removal of stains at postcleaning 15 minutes and 8 hours immersion time in both the denture bases and 8 hours immersion time is better.ConclusionBoth cleansers were effective in removing stains from denture surface, and Dentural is a better cleanser than Fitty Dent for all the postcleansing stages.Clinical significanceAdequate removal of extrinsic stains from denture surface is essential for the health of the supportive area. The clinician must suggest an acceptable cleansing regime to the patient.How to cite this articleGopalakrishnan S, Kashinath KR, Mathew P. Evaluation of Destaining Property of Denture Cleansers on Heat-cured Denture Base Resins using Common Indian Food Stains. Int J Prosthodont Restor Dent 2017;7(2):53-59.