High-impact Denture Base Resins Research Articles

Effect of Different Chemical Surface Treatments on the Shear Bond Strength of Acrylic Teeth With Different High-Impact Denture Base Resins.

Introduction The debonding of acrylic teeth from the denture base, particularly in cases of prominent ridges, is a common problem faced by clinicians and patients. The present study was conducted to assess the effects of various chemical treatments on the shear bond strength (SBS) of acrylic teeth bonded to different high-impact denture base materials. Materials and methods The present in vitro study was conducted on 80 wax specimens with acrylic teeth bonded to two high-impact denture base materials (DPI Tuff (DPI Dental Products of India Ltd, Mumbai) and Trevalon HI (Trevalon HI, Dentsply, Karnataka)). The two main groups were further divided into four subgroups of 10 specimens each, depending on the chemical treatment at the ridge lap area of the tooth: control group without any chemical treatment, chemical surface treatment (CST) with dichloromethane and monomer mix, CST with ethyl acetate, and CST with acrylic adhesive cyanoacrylate. The SBS was tested using a universal testing machine (UTM). Analysis of variance (ANOVA) and post-hoc Tukey tests were used for statistical analyses. Results The mean SBS of Group A (DPI Tuff) was 111.75 Nas compared to 118 N in Group B (Trevalon HI). The differences were statistically significant (p<0.05). ANOVA and post-hoc Tukey's tests revealed significant differences between subgroups. The highest mean SBS was noted with a dichloromethane and monomer mix (1:1 volume), followed by the ethyl acetate, control, and cyanoacrylate subgroups. Conclusion The cross-linked acrylic teeth treated with a dichloromethane and monomer mixture (1:1 by volume), processed with Trevalon HI high-impact denture base resin had the highest SBS and thus were indicated for bonding teeth with the suggested denture base.

Mechanical Properties Evaluation of Three Different Materials for Implant Supported Overdenture: An In-Vitro Study.

Aim: the aim of this study was to compare the flexural strength and elastic modulus of three-dimensionally (3D) printed, conventional heat-cured, and high-impact implant-supported overdenture materials specimens. Materials and Methods: Thirty implant-supported overdenture materials specimens (bar-shaped, 65.0 × 10.2 × 5.1 ± 0.2 mm3) with one central hole were fabricated using 3D-printed, heat-cured conventional, and high-impact denture base resins (n = 10/group). Autopolymerizing acrylic resin was used to attach titanium matrix housings to the central holes of the specimens. A three-point bending test was conducted using a universal testing machine and a model analog with a crosshead speed of 5 mm/min. The indicative flexural strength and elastic modulus were recorded. Data were statistically analyzed using analysis of variance (ANOVA) and the Tukey tests at α = 0.05. Results: One-way ANOVA revealed a significant effect of denture base material on the flexural strength (p < 0.001) but not on the elastic modulus (p = 0.451) of the evaluated materials. The flexural strength of the 3D-printed specimens (95.99 ± 9.87 MPa) was significantly higher than the conventional (77.18 ± 9.69 MPa; p < 0.001) and high-impact ones (82.74 ± 7.73 MPa; p = 0.002). Conclusions: The maximum flexural strength was observed in the 3D-printed implant-supported overdenture material specimens, which might indicate their suitability as an alternative to the conventionally fabricated ones. Flexural strength and elastic modulus of conventional and high-impact heat-cured implant-supported overdenture materials specimens were comparable.

Evaluating bond strength of acrylic teeth to conventional and high impact denture base resin incorporating various groove designs

Purpose: In spite of chemical union between acrylic resin teeth and acrylic denture base material, detachment of teeth particularly anterior teeth is a frequent observation. The purpose of this study was to evaluate shear bond strength between denture base resin and acrylic resin denture teeth after incorporating various grooves on the ridge lap area. Materials &amp; Methods: A total of 60 samples were prepared and divided into two groups with 30 samples each. Sample in group I were processed with conventional resin whereas in group II with high impact resin. The teeth in each group were subjected to no treatment, vertical groove &amp; Horizontal retentive goove placement on the ridge lap area. In each group unmodified teeth served as control. A shear force was applied at an angle of 130 degrees to the lingual surface of teeth using instron universal testing machine until fracture occurred. Data obtained was statistically analysed using Post hoc and Mann-Whitney Test. Results: Unmodified resin teeth showed the least bond strength. Modification of teeth with vertical and horizontal groove significantly improves the bond strength with denture resin. A significantly greater force was required to fracture teeth from high impact resin and with vertical groove.

Comparison of the Flexural Strength and Surface Roughness of Conventional Heat Cure and High Impact Denture Base Resins on Microadditions of Carbon Nanotubes- An In Vitro Study

Background and Objectives: Midline fracture of dentures and fractures due to sudden impact on denture bases, like accidental dropping, are common. The limitation that the strength of these materials displays sets a need for further improvement of the polymethylmethacrylate resin. Studies have demonstrated that carbon nanotubes possess outstanding mechanical properties of flexural and impact strengths. The present study evaluated and compared the flexural strength and surface roughness on reinforcing conventional heat cure denture base resins and high impact resins with carbon nanotubes. Method: A metal template of specific dimensions 65 mm × 10 mm × 3 mm was fabricated and flasked to obtain moulds. Monomer (methylmethacrylate) containing 1wt% carbon nanotubes was mixed with DPI and Lucitone polymers respectively and packed into the moulds to obtain 20 samples for each. Monomer without nanoparticles was used to fabricate 20 more samples for each resin. Following curing and deflasking, a total of 80 specimens were finished to required dimensions. Surface roughness of each specimen was evaluated using an optical profilometer. The flexural strengths were evaluated using a Universal Testing Machine. Results: The results showed that there was statistically significant difference among the flexural strength values of the groups with microadditions of CNTs when compared to the groups without microadditions. The surface roughness values, on comparison, showed no statistical significance. Interpretation and Conclusion: On comparison of the values obtained, the study concludes that flexural strength significantly improved on addition of carbon nanotubes. However, the comparison of surface roughness values suggested that incorporation of nanotubes does not increase the surface roughness of denture resins.

Comparative Study of the Flexural Strength of High Impact Denture Base Resins Reinforced by Silver Nanoparticles and E-Glass Fibres: An In-Vitro Study

Introduction: In spite of being proven a promising material of choice as a denture base material, the fracture resistance of conventional poly methyl methacrylate could be enhanced. Aim: This in vitro study was conducted to evaluate and compare the flexural strengths of three types of commercially available heat cure, high impact denture base resins reinforced with either silver nanoparticles or E-glass fibres. Materials and Methods: Three commercially available heat cures, high impact denture base resins (Trevalon HI- Dentsply, Acryl H - PyraxPolymars and Acralyn H - Asian Acrylates) were selected for the study. The three types of resins were further subdivided into three subgroups (Control group, Resin incorporated with 0.5% silver nanoparticles and Resin incorporated with 2% E-glass fibres) of 10 samples each achieving a total of 90 samples. The samples were subjected to a 3-point bending test for evaluation of flexural strength. The data were analysed using one-way ANOVA. Results: Acralyn H resin group showed the highest result for mean flexural strength for all the three subgroups. There was an increase in the flexural strength of Trevalon HI and Acralyn H resin groups on addition of either silver nanoparticles (AgNPs) or E-glass fibres (p<0.05), but a decrease in flexural strength on addition of AgNPs to Acryl H resin group and negligible change on addition of E-glass fibres. Difference in flexural strength between the three types of materials was observed but there was no significant difference in between the subgroups of each type of denture base resin except type 2 (Trevalon HI- Dentsply) where a significant change was observed. Conclusion: The addition of E-glass fibres or silver nanoparticles causes a change in flexural properties of high impact, heat cure denture base resins. However, the change in mechanical properties is highly dependent on the brand of material used.

Evaluation of the mechanical properties of high impact denture base resin with different polymer to monomer ratios: An In vitro study

Aim: This study aims to evaluate the flexural strength, hardness, and impact strength of heat-cured high-impact denture base resins with different polymer/monomer ratios. Materials and Methods: A total of 150 acrylic samples were prepared using high impact denture base resin (Travelon Hi). The samples were divided into five groups based on different powder/liquid ratios (g/ml) with 30 samples in each group. The P/L ratio in Group 1 (Ratio - 2.2:1) was the manufacturer's recommended ratio and was used as control. In Group 2, the ratio was 2.7:1, in Group 3, the ratio was 3.2:1, in Group 4, the ratio was 1.9:1, and Group 5 the ratio was 1.6:1. Each group with 30 samples was further subdivided into three different subgroups comprising 10 samples each, based on the properties to be evaluated, i.e., for flexural strength, hardness, and impact strength evaluation. The samples were tested for flexural strength, Vicker's hardness number (VHN) and impact strength. One-way ANOVA including post hoc-Tukey's tests was used to calculate the difference of means for quantitative variables and for intergroup comparison as well. Results: The results showed that the flexural strength values and VHN values showed a similar trend. The values decreased significantly as the ratio was increased or decreased from the control group. The results also showed that there was nonsignificant difference between the mean impact strength values for all the groups. Conclusion: For reinforced resins or high impact resins, the manufacturer's recommended polymer/monomer mixing ratio should be used to obtain the appropriate strength of the material.

Comparative evaluation of the tensile bond strength of two silicone based denture liners with denture base resins

BackgroundTo evaluate and compare tensile bond strength of two silicone based liners with heat cure and heat cure high impact denture base resin at baseline and after storage in artificial saliva for 30 and 60 days. MethodHeat cure conventional and high impact acrylic blocks (120 blocks each) prepared with final test specimen of two blocks of each resin with a liner. The baseline samples and those tested after 30 and 60 days interval stored in artificial saliva in thermal incubator, all were pulled apart in UTM at 20mm/min. The tensile bond strength and mode of failure (adhesive/cohesive) were assessed. Mean, SD determined and analysis using one way ANOVA and paired ‘t’ test. ResultsThe highest mean tensile bond strength (1.028MPa) and the least i.e. 0.289MPa was observed with Permaflex silicone liner against heat cure PMMA after storage in artificial saliva at 37±1°C. ConclusionThe study rejected the null hypothesis because storage time in artificial saliva affected the bond strength of the resilient liners examined. The results revealed a statistically significant difference (p<0.05) of artificial saliva storage on the bond strength of both the liners. After storage in artificial saliva for 30 days and 60 days at 37±1°C, all the specimens showed a significant reduction in the tensile bond strength.

Comparison of flexural strength in three types of denture base resins: An in vitro study

Aim:The aim of this study was to evaluate whether the flexural strength of a commercially available, heat polymerized acrylic denture base material could be improved using reinforcements.Materials and Methods:A total of 30 specimens (65 mm × 10 mm × 3 mm) were fabricated; the specimens were divided into three groups with 10 specimens each. They were Group 1 - conventional denture base resins, Group 2 - high impact denture base resins, and Group 3 - glass reinforced denture base resins. The specimens were loaded until failure on a three-point bending test machine. An one-way analysis of variance was used to determine statistical differences among the flexural strength of three groups. Data were analyzed by SPSS software version 21.0© (IBM Corporation, Armonk, NY, USA) and the results were obtained.Results:The flexural strength values showed statistically significant differences among experimental groups (P < 0.005).Conclusion:Within the limitations of the study polymethyl methacrylate (PMMA) reinforced with glass fibers showed the highest flexural strength values this was followed by PMMA reinforced with butadiene styrene, and the least strength was observed in the conventional denture base resins.

Microtensile bond strength of different acrylic teeth to high-impact denture base resins.

This study evaluated the effect of denture base acrylic, denture tooth composition, and ridge-lap surface treatment on the microtensile bond strength (μTBS) of three commercially available denture teeth and two injection denture processing systems. Sixteen experimental groups were formed (n = 3), according to denture tooth surface treatment (no treatment or surface treatment recommended by the manufacturer), denture base processing technique and acrylic (SR-Ivocap-Ivocap Plus or Success-Lucitone 199), and tooth type-composition at bonding interface (BlueLine DCL-PMMA, Portrait IPN-PMMA, Phonares II-PMMA, Phonares II-NHC). Rectangular bar specimens with a 1 mm(2) cross sectional area were fabricated and subsequently thermocycled at 10,000 cycles between 5°C and 55°C with a 15-second dwell time. Select specimens underwent μTBS testing in a universal testing machine with a 1 kN load cell at 0.5 mm/min crosshead speed. Data were analyzed statistically by two and three-way ANOVA and Tukey post hoc test (α = 0.05). Mean μTBS ranged between 56.2 ± 5.6 and 60.8 ± 5.0 N/mm(2) for the Ivocap Plus specimens and 13.3 ± 5.12 to 60.1 ± 6.0 N/mm(2) for the Lucitone 199 specimens. Among the Ivocap specimens, BlueLine DCL and Phonares II NHC had significantly higher μTBS than Portrait IPN to Ivocap Plus acrylic. There were no statistically significant differences among Blueline, Phonares II PMMA, and Phonares II NHC, or between Phonares II PMMA and Portrait IPN. Within the Luctione 199 specimens, there was a significantly higher μTBS for BlueLine DCL and Phonares II NHC denture teeth with the manufacturer-recommended surface treatment when compared to control surface. BlueLine, Portrait, and Phonares II PMMA groups achieved significantly higher mean μTBS than the Phonares II NHC group. There were no statistically significant differences among BlueLine, Portrait, and Phonares II PMMA groups. When evaluating the μTBS of PMMA and NHC denture teeth to base resins, a stronger bond was achieved using materials produced by the same manufacturer. Within the Luctione 199 specimens, the Phonares II NHC group demonstrated significantly lower bond strength than other specimens, suggesting that gross ridge-lap reduction of NHC denture teeth is not recommended if a base acrylic by a different manufacturer from the tooth is going to be used.

Effect of Trichloromethane on the Bond Strengths between Acrylic Teeth and Different Heat-cured Denture Bases: A Comparative Study

This study is to evaluate the role of 1:1 v/v 30% trichloromethane and monomer solvent in enhancing the durability of bonding between cross-linked acrylic teeth and different heatcured denture bases with or without mechanical preparations made on ridge lap portion of the artificial teeth. Two high impact denture base resin materials (Trevalon HI, DeTrey, UK, and DPI Tuff, Mumbai) and one nonhigh impact denture base resin material (DPI Quick Set, Mumbai) were selected to form three groups. Each group contains 30 specimens prepared by five different methods. A mixture of 30% trichloromethane and monomer, mixed in the ratio of 1:1 and applied for 1 minute on the ridge lap area of experimental specimens of methods--B, C, D and E (Specimens of method--A being control group, where no alterations were made at the ridge lap portion of acrylic teeth) before curing. Hounsfield universal testing machine is employed to evaluate the comparative bond strengths. No significant difference was seen in bond strengths between specimens of experimental methods in all groups. When each group was assessed separately method B specimens in group 1 (739.2 N), group 2 (758 N) and method D specimens in group 3 (729 N) showed highest mean bond strengths. Control group specimens showed the least bond strength (400-460 N) in all groups with more adhesive failures. Ridge lap portion of the specimens treated with chemical solvent as in method B showed increased bond strength in groups 1 and 2. Hence, this is a preferred method. Evaluation of effect of different chemical and mechanical preparations at the ridge lap areas of acrylic teeth before acrylization helps the clinician and technician to overcome the problem of debonding of teeth from denture bases and in turn provides better quality prosthesis to the patient.

An investigation into the transverse and impact strength of a new indigenous high-impact denture base resin, DPI- tuff and its comparison with most commonly used two denture base resins

An investigation into the transverse and impact strength of a new indigenous high - impact denture base resin, DPI- TUFF and its comparison with two most commonly used two denture base resins. INTRODUCTION: The heat cure denture base resins are extensively used for their excellent properties such as ease of handling, durability and esthetics etc. However, their strength properties are field for ongoing research, leading to various modifications of the resins to improve its strength, which include the high - impact resins. AIMS AND OBJECTIVES: A study was carried out to evaluate and compare the transverse and impact strength of a new high - impact denture base resin and it was compared with two most commonly available resins in the market. The materials used were DPI-TUFF, Lucitone 199 and DPI heat cure denture base resins. MATERIALS AND METHODS: A total of 120 resin samples were prepared (60 samples for transverse strength and 60 samples for impact strength) from three different materials. The samples were prepared using the short and long curing cycle and tested under dry conditions and after immersion in water for a week. RESULTS AND DISCUSSION: The obtained values for transverse and impact strength were subjected to statistical analysis. A student's T-test was performed to determine the difference between the materials selected. CONCLUSION: The DPI-TUFF high impact denture base resin appears to be comparatively superior to the other two resins, with mean transverse strength of 115.0 MPa and impact strength of 18.95 kJ/m2. The dry strength of the samples of the materials tested show that it is greater than after immersion of the samples in water at 37oC for a week. The long curing cycle shows considerably higher values of transverse and impact strength as compared to short curing cycle.

Effect of retention grooves on tooth-denture base bond

The bond strength of acrylic resin teeth with and without retention grooves processed onto standard and high-impact denture base resin was investigated. A shear compressive force was applied at an angle of 130 degrees to the lingual surface of the teeth until fracture occurred. The values were subjected to a two-way analysis of variance with repeated measures. Canine teeth bonded better than central or lateral incisors ( p < 0.01). A significantly greater force was required to fracture teeth from high-impact resin ( p < 0.01). Vertical retention grooves enhanced bond strength ( p < 0.01).