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Journal of the Mechanical Behavior of... Oct 2022To evaluate the effect of simulated brushing and chemical disinfection on the surface roughness and color stability of CAD-CAM denture base materials and to compare with...
PURPOSE
To evaluate the effect of simulated brushing and chemical disinfection on the surface roughness and color stability of CAD-CAM denture base materials and to compare with those of a heat-cured denture base material.
MATERIAL AND METHODS
Disk-shaped specimens (Ø 10mm × 2 mm) were prepared from 3 CAD-CAM denture base resins (AvaDent, Ava; Merz M-PM, Merz; Polident d.o.o, Poli) and a heat-cured polymethylmethacrylate resin (Promolux, Conv) (n = 30). After polishing, baseline surface roughness (R) and color coordinates were measured. The measurements were repeated after 20000 cycles of simulated brushing, and the specimens were divided into 3 groups according to disinfection protocol (distilled water, 1% sodium hypochlorite (NaOCl), and effervescent tablet) (n = 10). After 9 cleaning cycles over a period of 20 days, R and color coordinates were remeasured. Color differences (ΔE) were calculated by using CIEDE2000 formula. One-way analysis of variance (ANOVA) and pairwise t-tests were used to analyze R and ΔE data, while repeated measures ANOVA test was used to compare baseline, after brush, and after disinfection R values (α = 0.05).
RESULTS
Brushing did not affect the R values of tested materials (P ≥ .08). Both before and after brushing, Merz and Conv had higher R values than Poli and Ava (P < .001). Among disinfectants, effervescent tablet led to the lowest R for Merz (P = .003) and the highest R for Poli (P ≤ .039). Only NaOCl resulted in significant differences among the R of materials (P < .001), as Merz and Conv had higher R values than Poli (P ≤ .002). Repeated measures ANOVA revealed that effervescent tablet disinfection of Merz led to lower R values than those of baseline and after brushing (P ≤ .042). After brushing, Ava and Conv had higher ΔE values compared with Merz and Poli (P ≤ .015). When compared with other disinfection protocols, effervescent tablet led to higher ΔE values for Merz and Poli (P < .001). Significant differences were observed among materials when NaOCl was used; Conv had higher ΔE values than Ava and Merz (P = .004).
CONCLUSIONS
Brushing did not increase the surface roughness of materials. Disinfection protocol's effect on the surface roughness varied. The effect of brushing on the color of materials varied; color of Ava and Conv was affected from brushing more than the other materials. Color stability of materials varied depending on the disinfection protocol. Effervescent tablet caused higher color change with Merz and Poli compared with other disinfectants. NaOCl led to small color change for Poli, Ava, and Merz materials.
Topics: Color; Computer-Aided Design; Denture Bases; Disinfectants; Disinfection; Materials Testing; Surface Properties
PubMed: 35917636
DOI: 10.1016/j.jmbbm.2022.105390 -
The Journal of Advanced Prosthodontics Oct 2020The bond strengths between resin denture teeth with various compositions and denture base resins including conventional and AD/CAM purposed materials were evaluated to...
PURPOSE
The bond strengths between resin denture teeth with various compositions and denture base resins including conventional and AD/CAM purposed materials were evaluated to find influence of each material.
MATERIALS AND METHODS
Cylindrical rods (6.0 mm diameter × 8.0 mm length) prepared from pre-polymerized CAD/CAM denture base resin blocks (PMMA Block-pink; Huge Dental Material, Vipi Block-Pink; Vipi Industria) were bonded to the basal surface of resin teeth from three different companies (VITA MFT®; VITA Zahnfabrik, Endura Posterio®; SHOFU Dental, Duracross Physio®; Nissin Dental Products Inc.) using resin cement (Super-Bond C&B; SUN MEDICAL). As a control group, rods from a conventional heat-polymerizing denture base resin (Vertex™ Rapid Simplified; Vertex-Dental B.V. Co.) were attached to the resin teeth using the conventional flasking and curing method. Furthermore, the effect of air abrasion was studied with the highly cross-linked resin teeth (VITA MFT®) groups. The shear bond strengths were measured, and then the fractured surfaces were examined to analyze the mode of failure.
RESULTS
The shear bond strengths of the conventional heat-polymerizing PMMA denture resin group and the CAD/CAM denture base resin groups were similar. Air abrasion to VITA MFT® did not improve shear bond strengths. Interfacial failure was the dominant cause of failure for all specimens.
CONCLUSION
Shear bond strengths of CAD/CAM denture base materials and resin denture teeth using resin cement are comparable to those of conventional methods.
PubMed: 33149845
DOI: 10.4047/jap.2020.12.5.251 -
Dental Materials Journal Sep 2021The aim of this study was to optimize the preparation method of polymethyl methacrylate (PMMA) denture base loaded with nano silver (NAg), to more effectively and safely...
The aim of this study was to optimize the preparation method of polymethyl methacrylate (PMMA) denture base loaded with nano silver (NAg), to more effectively and safely impart sustainable antibacterial functions. NAg solution was synthetized and mixed with acrylic acid and methyl methyacrylate (MMA) monomer in order to prepare a new type of NAg solution (NS)/polymer methyl methacrylate denture base specimens (NS/PMMA). The surface morphology, mechanical strength, antimicrobial activity, anti-aging performance, cytotoxicity and biocompatibility of NS/PMMA denture base were evaluated in comparison with specimens fabricated using traditional NAg adding methods and NAg-free denture base. The aesthetic characteristics and mechanical strength of NS/PMMA denture base met the clinical application requirements. Meanwhile, NS/PMMA denture base showed better antibacterial activity, anti-aging properties, no cytotoxicity and displayed exceptional biocompatibility. NS/PMMA denture base thus has great potential for clinical application.
Topics: Acrylic Resins; Animals; Denture Bases; Esthetics, Dental; Materials Testing; Metal Nanoparticles; Polymethyl Methacrylate; Silver; Surface Properties
PubMed: 33980747
DOI: 10.4012/dmj.2020-129 -
Dental Materials : Official Publication... Dec 2023To evaluate the physical and mechanical properties of three-dimensional (3D) printed denture base resin incorporating TiO2 nanoparticles (NPs), subjected to a physical...
OBJECTIVES
To evaluate the physical and mechanical properties of three-dimensional (3D) printed denture base resin incorporating TiO2 nanoparticles (NPs), subjected to a physical ageing process.
METHODS
Acrylic denture base samples were prepared by a Stereolithography (SLA) 3D printing technique reinforced with different concentrations (0.10, 0.25, 0.50, and 0.75) of silanated TiO NPs. The resulting nanocomposite materials were characterized in terms of degree of conversion (DC), and sorption/solubility flexural strength, impact strength, Vickers hardness and Martens hardness and compared with unmodified resin and conventional heat-cured (HC) material. The nanocomposites were reassessed after subjecting them to ageing in artificial saliva. A fractured surface was studied under a scanning electron microscope (SEM).
RESULTS
The addition of TiO NPs into 3D-printed resin significantly improved flexural strength/modulus, impact strength, Vickers hardness, and DC, while also slightly enhancing Martens hardness compared to the unmodified resin. Sorption values did not show any improvements, while solubility was reduced significantly. The addition of 0.10 wt% NPs provided the highest performance amongst the other concentrations, and 0.75 wt% NPs showed the lowest. Although ageing degraded the materials' performance to a certain extent, the trends remained the same. SEM images showed a homogenous distribution of the NPs at lower concentrations (0.10 and 0.25 wt%) but revealed agglomeration of the NPs with the higher concentrations (0.50 and 0.75 wt%).
SIGNIFICANCE
The outcomes of this study suggested that the incorporation of TiO NPs (0.10 wt%) into 3D-printed denture base material showed superior performance compared to the unmodified 3D-printed resin even after ageing in artificial saliva. The nanocomposite has the potential to extend service life of denture bases in future clinical use.
Topics: Denture Bases; Surface Properties; Saliva, Artificial; Materials Testing; Printing, Three-Dimensional; Nanoparticles
PubMed: 37839997
DOI: 10.1016/j.dental.2023.10.005 -
European Journal of Dentistry Feb 2019This study aimed to assess the effect of reinforcement, denture base thickness, and acrylic resin types on dynamic and static fracture strength in mandibular implant...
OBJECTIVE
This study aimed to assess the effect of reinforcement, denture base thickness, and acrylic resin types on dynamic and static fracture strength in mandibular implant overdentures with bar attachment.
MATERIALS AND METHODS
One hundred and eight experimental mandibular implant overdentures with bar attachments were fabricated in three main groups, namely unreinforced (control: C), reinforced with unidirectional glass fibers (FR), and Co-Cr cast metal (MR). Each group included denture bases of 2-, 3-, and 4-mm thicknesses and produced with conventional (CA) and high-impact acrylic (HIA) resins. Specimens were thermocycled (5,000 times, 5-55°C) then subjected to a 400,000 cyclic load regime. Unbroken specimens were then loaded until fracture by a universal testing machine. Differences in mean fracture resistance among the groups were compared using the one-way analysis of variance (with Tukey's honestly significant difference test) and Student's -tests (α = 0.05).
RESULTS
Fracture strength increased significantly when the denture base thickness was increased ( = 0.001. The 2-mm denture base thickness was not enough for reinforcement. The fracture strength of the FR groups was significantly higher than other groups for 3- and 4-mm thicknesses ( = 0.001). The fracture strength of the HIA resin was significantly higher than CA resin in FR groups ( = 0.029 and = 0.001). MR groups showed the weakest fracture strength.
CONCLUSIONS
The 2-mm denture base thickness had sufficient fracture strength without reinforcement and a positive relationship between acrylic resin thickness and fracture resistance was found.
PubMed: 31170769
DOI: 10.1055/s-0039-1688533 -
Materials (Basel, Switzerland) Jul 2020(1) Background: To date, no information on the polishability of milled and 3D-printed complete denture bases has been provided, which is relevant in terms of plaque...
(1) Background: To date, no information on the polishability of milled and 3D-printed complete denture bases has been provided, which is relevant in terms of plaque accumulation. (2) Methods: three groups ( = 30) were manufactured using the cold-polymerization polymethilmethacrilate, milling (SM) and 3D printing (AM). 10 specimens of each group were left untreated (reference). 10 more specimens were pre-polished (intermediate polishing) and 10 final specimens were highgloss polished. An additional 20 specimens were 3D printed and coated with the liquid resin (coated), 10 of which were additionally polished (coated + polished). For each group R and R values, gloss value and REM images were obtained. (3). The "highgloss-polished" specimens showed statistically lower R and R values in the SM, followed by AM and conventional groups. In the AM group statistically lower surfaces roughness was revealed for highgloss-polished, "coated + polished", and "coated" specimens, respectively. (4) Conclusions: The milled specimens demonstrated superiors surface characteristics than 3D printed and conventionally produced after polishing. The polished specimens demonstrated superior surface characteristics over coated specimens. However, the surface roughness by both polished and coated specimens was within the clinically relevant threshold of 0.2 µm.
PubMed: 32722240
DOI: 10.3390/ma13153305 -
Journal of Ayub Medical College,... 2020Conventional heat cure polymerized acrylic resin(unmodified) is most acceptable denture base material in dentistry since decades. It has been modified with reinforcement...
BACKGROUND
Conventional heat cure polymerized acrylic resin(unmodified) is most acceptable denture base material in dentistry since decades. It has been modified with reinforcement of fillers and different processing techniques were introduced to enhance its mechanical and physical properties. The objective of this research is to determine and compare the effect of different processing techniques on flexural strength of modified and unmodified denture base acrylic resin. Air circulating oven is introduced for the first time in this study and its efficacy is also compared with other conventional processing techniques.
METHODS
In this study total number of 114 rectangular specimens were fabricated by conventional heat cured acrylic (Stellon QC 20, Dentsply) for Group A (n=57), and rubber reinforced acrylic resin (High impact, Meadway) for Group B (n=57). Three equipment including water bath, dry oven and air circulating oven were utilized for processing specimens individually. Each sub-group of processing techniques (n=19) were tested for flexural strength through a three-point bending test by a universal testing machine. The statistical analysis initiated with descriptive analysis followed by independent t test for mean comparison of flexural strength of all three processing techniques among both testing group. One-way ANOVA and 2-way ANOVA followed by Scheffe post hoc test were also applied. p-value of 0.05 or less was considered as significant.
RESULTS
Statically significant p-value <0.001 was found in response of flexural strength in all processing techniques (water bath, dry oven, air circulating oven) of both testing groups. Water bath processing demonstrated highest flexural strength values in both denture base material used in this study. The unit used for flexural strength was MPa.
CONCLUSION
This study manifested highest flexural strength in conventional and rubber reinforced heat cure samples when processed through water bath. Air circulating oven also presented acceptable flexural strength in conventional heat cure acrylic resin specimens when compared with other techniques.
Topics: Acrylic Resins; Denture Bases; Flexural Strength; Materials Testing
PubMed: 33754529
DOI: No ID Found -
Journal of Pharmacy & Bioallied Sciences Nov 2021There are numerous artificial denture tooth materials available of which acrylic resin teeth were used widely. The resin teeth bond chemically to the denture base resin,...
BACKGROUND
There are numerous artificial denture tooth materials available of which acrylic resin teeth were used widely. The resin teeth bond chemically to the denture base resin, and this bonding is affected by numerous intrinsic and extrinsic factors. The type of cross-linker in the denture base monomer is one such factor which has a questionable influence on the bond strength. Recently, cycloaliphatic comonomer was added in the methyl methacrylate monomer and the resultant novel copolymer possessed good physico-mechanical and biological properties.
PURPOSE
The purpose of this study was to evaluate the shear bond strength (SBS) between acrylic denture tooth and resultant novel copolymer after cyclic loading and thermal aging.
MATERIALS AND METHODS
Sixty central incisor denture teeth were bonded to three types of acrylic denture base resin groups ( = 20 per group) categorized based on the presence of the cycloaliphatic comonomer - Control group (G0): denture bases without cycloaliphatic comonomer and trial groups G10 and G20 contain 10 vol.% and 20 vol.% comonomer, respectively, substituted in the denture base monomer component. The specimens were processed and subjected to cyclic loading and thermal aging which was then followed by SBS testing.
RESULTS
G20 possessed the highest SBS followed by G10. G0 had the least SBS. All the specimens of the control and trial groups exhibited adhesive-cohesive mixed failure at the resin tooth-base resin interface.
CONCLUSION
The addition of cycloaliphatic comonomer increased the SBS between the resultant novel copolymer and the resin teeth after cyclic loading and thermal aging.
PubMed: 35017945
DOI: 10.4103/jpbs.jpbs_212_21 -
Journal of Pharmacy & Bioallied Sciences Jul 2022The aim of the present study was to evaluate the cytotoxicity of heat-cure denture base resin (PMMA) modified with recycled denture base resin at 10%, 20%, 30%, 40%,...
AIM
The aim of the present study was to evaluate the cytotoxicity of heat-cure denture base resin (PMMA) modified with recycled denture base resin at 10%, 20%, 30%, 40%, and 50% (w/w) concentration.
MATERIALS AND METHODS
A total of 30 disk-shaped specimens were prepared and divided into six groups ( = 5). The Control group (R) consisted of unmodified processed denture base resin, the experimental group consisted of denture base resin processed with substitution of 10% 20%, 30%, 40%, and 50% (w/w) of recycled denture base resin (R, R R R, and R). Eluates were prepared using five sterile specimens of each group. The mouse fibroblast cell line (L929) was seeded in a 96-well cell plate system at a concentration of 1 × 10 cells/well in the DMEM medium with 1× antibiotic and antimycotic solution and 10% fetal bovine serum at 37°C with 5% CO and incubated in a CO incubator for 48 h. MTT assay was applied and the absorbance was measured at 570 nm using a microplate reader to assess the cytotoxicity. One-way analysis of variance (ANOVA) along with post hoc Scheffe test was used to statistically compare the mean optical density (OD) values and cell survival/viability % amongst the groups.
RESULTS
No statistically significant difference was observed in the mean and standard deviation of the optical density and cell viability % of the test groups that were compared.
CONCLUSION
Modification of denture base resin using recycled PMMA does not have a cytotoxic effect on the mouse fibroblast cell line L929.
PubMed: 36110705
DOI: 10.4103/jpbs.jpbs_890_21 -
Journal of Applied Oral Science :... 2013This study evaluated the fracture toughness (FT) of denture base and autopolymerizing reline resins, with and without thermocycling (T).
OBJECTIVE
This study evaluated the fracture toughness (FT) of denture base and autopolymerizing reline resins, with and without thermocycling (T).
MATERIAL AND METHODS
Specimens of each material (denture base acrylic resin - Lucitone 550 - L; autopolymerizing reline resins - Ufi Gel Hard-UH, Tokuyama Rebase II-TR, New Truliner-NT and Kooliner-K), were produced, notched and divided into two groups (n=10): CG (control group of autopolymerizing reline resins and L): FT tests were performed after polymerization; TG (thermocycled group): FT tests were performed after T (5°C and 55°C for 5,000 cycles).
RESULTS
Results (MPa.m1/2) were analyzed by two-way ANOVA and Tukey's test (p=0.05). L exhibited the highest FT mean values in both groups (CG - 2.33; TG - 2.17). For the CG groups, NT showed the highest FT (1.64) among the autopolymerizing reline resins, and K the lowest (1.04). After T, when the autopolymerizing reline resins were compared, a statistically significant difference in FT was found only between the NT (1.46) and TR (1.00).
CONCLUSIONS
Thermocycling increased the FT of K and did not influence the FT of L, UH, TR and NT.
Topics: Acrylic Resins; Analysis of Variance; Dental Restoration Failure; Denture Bases; Denture Rebasing; Humans; Materials Testing; Polymerization; Silicone Elastomers; Stress, Mechanical; Temperature; Time Factors
PubMed: 23857648
DOI: 10.1590/1679-775720130061