Evaluation of Surface Roughness of Acrylic Denture Bases Polished Using Algishine, a Novel Polishing Material: An In Vitro Study.

Introduction Surface roughness (Ra) significantly impacts the aesthetic and functional qualities of dental prosthetics. Traditional polishing involves pumice, a material routinely used in dental practice. This study introduces Algishine as a potential cost-effective eco-friendly alternative. Materials and methods A 3D design software (Geomagic) created a Standard Tesselation Language (STL) file of 10 mm x 10 mm x 2 mm. 30 STL file outputs were generated. The output was milled in wax. This was then flasked and processed. 30 acrylic resin specimens were fabricated and divided into two groups. Group A was polished using traditional pumice, and Group B was polished using Algishine. The Ra of each sample was measured using surface profilometry, with three readings per sample averaged for each group. Results Kruskal-Wallis test was performed to compare the two groups with the pre-testing samples, which showed p<0.05; indicating that there was a significant difference between the two groups. The average Ra value for unpolished acrylic was 7.105, while the specimens polished with pumice showed an Ra value of 2.218; specimens polished with novel material Algishine showed an Ra value of 1.743. This illustrates that Algishine achieves surface smoothness significantly superior to commonly used polishing agent and pumice. Discussion The results of our study demonstrate that Algishine, a novel polishing material derived from recycled alginate, effectively reduces the Ra of acrylic resin. This finding has significant implications, both clinically and environmentally. The primary clinical benefit of a smoother acrylic resin surface is the enhanced aesthetic appearance and increased patient comfort. A polished surface reduces plaque accumulation, thereby decreasing the risk of oral infections and improving the longevity of the dental prosthesis. The results show that Algishine achieves surface smoothness comparable to or better than pumice indicating that it can maintain, if not enhance, these clinical outcomes. Dental professionals can confidently use Algishine, knowing it meets the high standards required for patient care. Conclusion Algishine effectively reduces the Ra of acrylic resin, suggesting it is a viable, eco-friendly alternative to traditional pumice for dental polishing procedures. This indicates potential benefits in maintaining clinical outcomes while promoting environmental sustainability.

Evaluation of microhardness, degree of conversion, and abrasion resistance of nanoglass and multiwalled carbon nanotubes reinforced three-dimensionally printed denture base resins.

PURPOSE: To assess the effect of nanoglass (NG) particles and multiwalled carbon nanotubes' (MWCNTs) addition on Vickers hardness (VH), degree of conversion (DC), and abrasion resistance of 3D-printed denture base resin. MATERIALS AND METHODS: 3D-printed denture base resin was reinforced using silanized NG and MWCNTs to obtain four groups: Control, 0.25 wt% NG reinforced resin, 0.25 wt% MWCNTs reinforced resin, and a combination group of 0.25 wt% of both fillers. All specimens (N = 176) were tested before and after thermal aging (600 cycles) for VH (n = 22), DC, and abrasion resistance (n = 22). Abrasion resistance specimens were subjected to 60,000 brushing strokes, and then assessed for surface roughness (Ra) and weight loss. Specimens were then scanned with a benchtop scanner before and after abrasion to produce a color map of topographical changes from superimposed images. Data were analyzed using ANOVA tests followed by Tukey post hoc test. Kruskal-Wallis test was used to compare percent change among groups, followed by Dunn post hoc test (α = 0.05). RESULTS: The interaction between nanofiller content and thermal cycling displayed a significant effect on VH and DC. The 0.25% NG expressed the highest VH before aging but revealed the highest percent decrease after aging. Nanofiller content, thermal aging, and brushing displayed a significant interaction impact on the Ra values. CONCLUSIONS: The addition of nanofillers resulted in an overall improvement in resin microhardness and abrasion resistance. The 0.25% MWCNTs group revealed the lowest Ra with the least percent change in VH and DC, while the combination one displayed the least change in weight.

The influence of the addition of titanium oxide nanotubes on the properties of 3D printed denture base materials.

INTRODUCTION: In this study, the effects of adding titanium dioxide nanotubes (TiO2) to 3D-printed denture base resin on the mechanical and physical properties of denture bases were examined for the first time. METHODS: The specimens were digitally created using 3D builder software from Microsoft Corporation through computer-aided design. In accordance with the test specifications for transverse strength, impact strength, hardness, surface roughness, and color stability, specimens were designed and printed with certain dimensions following relevant standards. TiO2 nanotubes (diameter: 15-30 nm and length: 2-3 µm) were added to the 3D-printed denture base resin (DentaBase, Asiga, Australia) at 1.0% and 1.5% by weight. Flexural strength, impact strength (Charpy impact), hardness, surface roughness, and color stability were evaluated, and the collected data were analyzed with ANOVA followed by Tukey's post hoc test (α = 0.05). Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDX) mapping were used to evaluate the dispersion of the nanotubes. RESULTS: Compared with those of the control group (0.0 wt.% TiO2 nanotubes), the average flexural, impact, and hardness values of the 1.0 and 1.5 wt.% TiO2 nanotube reinforcement groups increased significantly. Both nanocomposite groups showed significant color changes compared to that of the pure resin, and there was a considerable reduction in the surface roughness of the nanocomposites compared to that of the control group. CONCLUSION: Adding TiO2 nanotubes to 3D-printed denture base materials at 1.0 and 1.5 wt.% could enhance the mechanical and physical properties of the material, leading to better clinical performance. CLINICAL SIGNIFICANCE: In terms of clinical applications, 3D-printed denture base material has been shown to be a viable substitute for traditional heat-cured materials. By combining this with nanotechnology, existing dentures could be significantly enhanced, promoting extended service life and patient satisfaction while addressing the shortcomings of the current standard materials.

Effect of thermocycling on tensile bond strength of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 4 different denture liners: an in vitro study.

BACKGROUND: Digitally fabricated dentures may require relining due to continual alveolar ridge resorption. However, studies evaluating the tensile bond strength (TBS) of digitally fabricated dentures bonded to denture liners are lacking. This study aimed to evaluate the TBS of autopolymerized, heat-polymerized, milled, and 3D printed denture base materials bonded to 2 acrylic-based and 2 silicone-based denture liners, both before and after thermocycling. Additionally, the impact of thermocycling on the TBS were also evaluated. METHODS: The TBS of 4 different denture base materials (Palapress (PL), Vertex Rapid Simplified (VR), Smile CAM total prosthesis (SC), and NextDent denture 3D+ (ND)) bonded to 2 acrylic-based (GC Soft-Liner (GC) and Tokuyama Rebase II (RB)) and 2 silicone-based (Ufi Gel P (UP) and Sofreliner Tough M (ST)) denture liners were tested. Specimens (n = 8) were divided into non-thermocycling and thermocycling groups. Non-thermocycling specimens were tested after 24-hours water immersion, while thermocycling specimens were underwent 5000 cycle and were immediately tested. Mode of failure was examined under a stereomicroscope. Data were analyzed using 2-way ANOVA and Tukey HSD tests (α = 0.05), and independent samples t test (α = 0.05) for TBS between non-thermocycling and thermocycling groups. RESULTS: For the non-thermocycling groups, within the same denture liner material, no significant differences were found between denture base materials, except the ND + RB group, which had significantly lower TBS. For the thermocycling groups, within the same denture liner material, the TBS in the PL group exhibited the highest and the ND group exhibited the lowest. Within the same denture base material, in both non-thermocycling and thermocycling groups, the TBS in the ST group exhibited the highest; in contrast, that in the GC group exhibited the lowest. No significant differences were observed in TBS between non-thermocycling and thermocycling groups, except for denture base materials bonded to the ST group, SC + UP, and ND + UP groups. CONCLUSIONS: Milled denture base can be relined with acrylic-based or silicone-based denture liner. However, cautions should be exercised when relining 3D printed denture base. Thermocycling did not affect TBS between acrylic-based denture liners and denture bases. In contrast, it affected the bond between silicone-based denture liner and denture base.

Bonding Efficiency between Artificial Teeth and Denture Base in CAD/CAM and Conventional Complete Removable Dentures.

A common challenge encountered with both traditional and digitally produced dentures involves the extraction of artificial teeth from the denture base. This narrative review seeks to present an updated perspective on the adherence of synthetic teeth for denture base materials, employing diverse methods. Dental technicians often employ chemical approaches and mechanical techniques (including abrasion, laser treatment, and abrasive blasting) to augment the retention of denture teeth. However, the efficacy of these treatments remains uncertain. In certain instances, specific combinations of Denture Base Resin (DBR) materials and artificial teeth exhibit improved performance in conventional heat-cured dentures following these treatments. The primary reasons for failure are attributed to material incompatibility and inadequate copolymerization. As new denture fabrication techniques and materials continue to emerge, further research is imperative to identify optimal tooth-DBR combinations. Notably, 3D-printed tooth-DBR combinations have demonstrated reduced bond strength and less favorable failure patterns, while utilizing milled and traditional combinations appears to be a more prudent choice until advancements in additive manufacturing enhance the reliability of 3D-printing methods.

Comparison of perceived masticatory ability in completely edentulous patients treated with thermoplastic complete denture versus single implant-retained mandibular overdenture: a single-center prospective observational study.

Background: This study aimed to compare the perceived masticatory ability (PrMA) in completely edentulous patients (EDPs) with thermoplastic conventional complete dentures (CDs) versus single implant-retained mandibular overdentures. Methods: The current study was conducted in the outpatient Prosthodontic Clinic, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt. PrMA was evaluated in 45 completely edentulous patients (46% males, mean age 50.4 ± 4.7 years). Each patient received a thermoplastic PMMA complete denture (Polyan IC TM Bredent GmbH & Co.KG, Germany). The PrMA was evaluated at one-month and six-month intervals of denture use. An immediate loading single implant was placed into the mid-symphyseal for each patient, and the denture was adjusted. Subsequently, the PrMA was reevaluated after one month and six months. The data were collected and statistically analyzed using the SPSS@V25 to assess the changes in PrMA. Results: The PrMA demonstrated improvement after six months of thermoplastic conventional denture use. However, this improvement was not statistically significant (p = 0.405). In addition, the PrMA showed a substantial increase following a single implant placement at one and six months (p < 0.001) of the overdenture use compared to the conventional denture. The PrMA insignificantly improved (p = 0.397) after six months of the single implant retained overdenture use. Discussion: The study's findings indicate that using immediate loading single implant-retained mandibular overdentures significantly improved PrMA in completely edentulous patients.

Fabrication and characterization of Ti-12Mo/xAl2O3 bio-inert composite for dental prosthetic applications.

Introduction: Titanium (Ti)-molybdenum(Mo) composites reinforced with ceramic nanoparticles have recently significant interest among researchers as a new type of bio-inert material used for dental prosthetic applications due to its biocompatibility, outstanding physical, mechanical and corrosion properties. The current work investigates the impact of alumina (Al2O3) nanoparticles on the properties of the Ti-12Mo composite, including microstructure, density, hardness, wear resistance, and electrochemical behavior. Methods: Ti-12Mo/xAl2O3 nanocomposites reinforced with different Al2O3 nanoparticles content were prepared. The composition of each sample was adjusted through the mechanical milling of the elemental constituents of the sample for 24 h under an argon atmosphere. The produced nanocomposite powders were then cold-pressed at 600 MPa and sintered at different temperatures (1,350°C, 1,450°C, and 1,500°C) for 90 min. Based on density measurements using the Archimedes method, the most suitable sintering temperature was found to be 1,450°C. The morphology and chemical composition of the milled and sintered composites were analyzed using back-scattering scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results and Discussion: The results showed that the addition of Mo increased the Ti density from 99.11% to 99.46%, while the incorporation of 15wt% Al2O3 in the Ti-12Mo composite decreased the density to 97.28%. Furthermore, the Vickers hardness and wear behavior of the Ti-Mo composite were enhanced with the addition of up to 5 wt% Al2O3. The sample contains 5 wt% Al2O3 exhibited a Vickers hardness of 593.4 HV, compared to 320 HV for pure Ti, and demonstrated the lowest wear rate of 0.0367 mg/min, compared to 0.307 mg/min for pure Ti. Electrochemical investigations revealed that the sintered Ti-12Mo/xAl2O3 nanocomposites displayed higher corrosion resistance against a simulated artificial saliva (AS) solution than pure Ti. The concentrations of Ti, Mo, and Al ions released from the Ti-12Mo/xAl2O3 nanocomposites in the AS solution were within the safe levels. It was found from this study that; the sample of the composition Ti-12Mo/5wt%Al2O3 exhibited appropriate mechanical properties, biocompatibility, corrosion resistance against the AS solution with acceptable ion concentration released in the biological fluids. Therefore, it can be considered as a new bio-inert material for potential applications in dental prosthetics.

Effectiveness of Denture Cleansers on Candida albicans Biofilm on Conventionally Fabricated, Computer-Aided Design/Computer-Aided Manufacturing-Milled, and Rapid-Prototyped Denture Base Resins: An In Vitro Study.

INTRODUCTION: Conventionally fabricated denture base resins have been used for over 150 years. Newer denture base resins can provide a superior fit and may be customized to the patient's characteristics, but the literature on their cleansibility remains limited. The oral cavity can be a hub for thousands of microflora. The maintenance of complete dentures by edentulous patients depends not only on the maintenance of the patient but also on the material used, biofilm adherence, and polishability. MATERIALS AND METHODS: Cuboid specimens of 10 × 5 × 2 mm were designed using the Meshmixer version 3.5 software (Meshmixer, Australia). The standard tessellation (STL) file was imported and sent for printing (NextDent, Netherlands) (Group 1), milling in polymethyl methacrylate (PMMA) (Ivotion, Ivoclar, Schaan, Liechtenstein) (Group 2), and wax milling (Upcera, China), followed by flasking, counter flasking, and packing using heat-cured acrylic resin (DPI, India) (Group 3). The obtained specimens were polished using pumice and sterilized using a UV sterilization unit. The specimens were then immersed in a suspension of candida broth. After three days of biofilm formation, a colony count was performed and noted as colony-forming units per milliliter (CFU/mL). Specimens were treated using Secure denture cleansing tablets (Ghent, New York), table salt (iodized table salt, Tata, India), Clinsodent (ICPA, Mumbai, India), and Polident denture cleansing powder (Polident, Ontario, Canada). A colony count was done after treatment, and the data were tabulated. Statistical analysis was done using SPSS software to compare the efficiency of denture cleansers in all three groups, and statistical significance was set at 0.05. The Kolmogorov-Smirnov test was done to confirm the normality of the data, followed by a one-way analysis of variance (ANOVA) test to compare the efficiency of denture cleansers on the removal of candida colonies. RESULTS: Milled denture base resins showed a significantly lower colony count when compared to printed and conventionally fabricated denture base resins. The denture cleansers showed high efficacy in all groups, with the most significant being Secure, which showed a mean difference ranging from 8.114 to 9.887 CFU/mL, followed by Clinsodent, showing a mean of 6.699-9.863 CFU/mL, followed closely by Polident, showing 4.964-7.114 CFU/mL, followed by table salt, being 5.254-8.920 CFU/mL. The 95% confidence interval confirmed statistical significance. CONCLUSION: The highest candida colony count was demonstrated by the conventional, followed by rapid prototyping, and was least with milled denture base resins. Following treatment with denture cleansers, Secure demonstrated almost complete eradication of colonies, making it the most effective option. Salt exhibited the lowest efficiency, followed closely by Polident and Clinsodent, and the most effective was Secure denture cleanser.

In vitro analysis of monomer leaching in modern dental materials: CAD milled, printed, traditional heat-processed, and auto-polymerizing denture base resins.

PURPOSE: Denture fabrication has shifted from traditional heat-processed and auto-polymerizing materials to computer-aided design and computer-aided manufacturing (CAD-CAM) milled and printed materials. The monomer in traditional materials can induce an allergic reaction in some patients. With the rise in the edentulous population and increasing demand for the fabrication of dentures, these newer materials should be studied for monomer leaching. The purpose of this study was to evaluate the ratio of residual monomer in materials being used for denture bases: CAD-milled polymethylmethacrylate (PMMA), printed denture base resin, heat-processed PMMA, and auto-polymerizing PMMA comparatively. MATERIALS AND METHODS: Milled, printed, heat-activated, and auto-polymerizing denture base specimens (n = 3 for each group, each test run three times) were fabricated according to manufacturer recommendations. Specimens were first immersed in deuterated chloroform (CDCl3), a deuterated organic solvent, to evaluate monomer leaching and to observe physical properties of the materials. NMR spectroscopy was used to evaluate the dissolution of materials and residual monomer to crosslinked polymer ratios at 1, 4, and 9 days. A second group of specimens was then immersed in deuterium oxide (D2O) to evaluate if the residual monomers would leach out of the system. The solution was then analyzed using nuclear magnetic resonance (NMR) spectroscopy for 1 month. The deuterated forms of chloroform (CDCl3) and water (D2O) were used to enable sample characterization by NMR. RESULTS: While the heat-processed, auto-polymerizing, and milled specimens possessed residual monomers, no significant monomer leaching was noted in the printed specimen, while immersed in CDCl3. Similarly, the printed specimen was most resistant to dissolution, as compared to the rest; dissolution of the specimen is indicative of little to no cross-linking. No detectable dissolution of monomer was seen when all specimens were immersed in D2O for up to 1 month. CONCLUSIONS: Residual monomers were not found in the printed denture material in this study in either CDCl3 or D2O, whereas CAD-milled and traditionally processed denture bases still have residual monomers within their respective systems when immersed in organic solvent. None of the specimens tested leached monomers into D2O.

Effect of various surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base.

PURPOSE: To evaluate the effect of mechanical, chemical, and mechanical-chemical surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base. MATERIALS AND METHODS: Maxillary central incisor teeth were treated with five different surface treatment methods: mechanical (sandblasting, T-shape diatoric holes), chemical (5% acetic acid solution, bonding agent), and mechanical-chemical (sandblasting + bonding agent) were embedded in thermoplastic nylon denture base (n = 10). A universal testing machine with a crosshead speed of 0.5 mm per minute was used to test the shear bond strength. Data obtained were statistically evaluated using one-way ANOVA and followed with Tukey post hoc test (α = 0.05) RESULTS: T-shaped diatoric holes exhibited significantly higher shear bond strength among the surface treatment groups, followed by sandblasting + bonding agent, sandblasting, bonding agent, and the acetic acid group (p < 0.001) CONCLUSION: T-shaped diatoric holes as a mechanical surface treatment showed higher shear bond strength than other methods.

Comparative Evaluation of the Flexural Strength of Heat-Activated Polymethyl Methacrylate Denture Base Resin With and Without 0.2% by the Weight of Silver Nanoparticles Cured by Conventional and Autoclave Methods: An In Vitro Study.

PURPOSE: Heat-activated polymethyl methacrylate (PMMA) is the most common and widely accepted denture base material. Two important drawbacks are the development of denture stomatitis and the high incidence of fracture of denture bases. The present study investigated the effect of adding 0.2% by weight of silver nanoparticles (AgNps) and using the autoclave method of terminal boiling on the flexural strength of heat-activated PMMA denture base resin. METHODS: A total of 40 samples of heat-activated PMMA blocks were divided into four groups, with 10 samples (n = 10) in each group. Group 1 consisted of unmodified heat-activated PMMA resin (PMMA-1) polymerized by the conventional method of terminal boiling (conventional curing); Group 2 consisted of 0.2% by weight AgNPs added to heat-activated PMMA resin (PMMA-2) polymerized by conventional curing; Group 3 consisted of PMMA-1 polymerized by the autoclave method of terminal boiling (autoclave curing); and Group 4 consisted of PMMA-2 polymerized by autoclave curing. The flexural strength was tested using a universal testing machine. Descriptive statistics were expressed as mean ± SD and median flexural strength. Kruskal-Wallis ANOVA with Mann-Whitney U post hoc test was applied to test for statistical significance between the groups. The level of significance was set at p<0.05. RESULTS: The results showed a statistically significant reduction in flexural strength in Group 2 compared to Group 1. The samples from Group 4 showed a statistically significant increase in flexural strength compared to Group 2. The Group 4 denture base had the highest flexural strength (115.72 ± 7.27 MPa) among the four groups, followed by Group 3 (104.16 ± 4.85 MPa). The Group 1 samples gave a flexural strength of 101.45 ± 3.13 MPa, and Group 2 gave the lowest flexural strength (85.98 ± 3.49 MPa) among the four groups tested. CONCLUSION: The reduction in flexural strength of the heat-activated PMMA denture base after adding 0.2% by weight of AgNP as an antifungal agent was a major concern among manufacturers of commercially available denture base materials. It was proved in the present study that employing the autoclave curing method of terminal boiling for the polymerization of 0.2% by weight of AgNp-added heat-activated PMMA denture base resulted in a significantly higher flexural strength compared to the conventional curing method of terminal boiling for polymerization. Unmodified heat-activated PMMA gave higher flexural strength values when polymerized by autoclave curing compared to the conventional curing method of terminal boiling.

An in vitro evaluation of bond strength and failure behavior between 3D-printed cobalt-chromium alloy and different types of denture base resins.

OBJECTIVES: This study aimed to evaluate the shear bond strength and failure behavior between cobalt-chromium (Co-Cr) alloy and different types of denture base resins (DBRs) over time. METHODS: Seventy-two disk-shaped specimens (8 mm in diameter and 2 mm in thickness) were manufactured using a selective laser melting technology-based metal 3D printer. Three types of DBRs were used: heat-cure (HEA group), cold-cure (COL group), and 3D-printable (TDP group) DBRs (n = 12 per group). Each DBR specimen was fabricated as a 5 mm × 5 mm × 5 mm cube model. The specimens of the TDP group were manufactured using a digital light processing technology-based 3D printer. Half of the DBRs were stored in distilled water at 37 °C for 24 h, whereas the remaining half underwent thermocycling for 10,000 cycles. Shear bond strength was measured using a universal testing machine; failure modes were observed, and metal surfaces were evaluated using energy dispersive spectrometry. RESULTS: The shear bond strength did not differ between the DBR types within the non-thermocycled groups. Contrarily, the TDP group exhibited inferior strength compared to the HEA group (P = 0.008) after thermocycling. All three types of DBRs exhibited a significant decrease in the shear bond strength and an increased tendency toward adhesive failure after thermocycling. CONCLUSIONS: The bond strength between 3D-printable DBRs and Co-Cr alloy was comparable to that of heat-and cold-cure DBRs before thermocycling. However, it exhibited a considerable weakening in comparison to heat-cure DBRs after simulated short-term use. CLINICAL SIGNIFICANCE: The application of 3D-printable DBR in metal framework-incorporated removable partial dentures may be feasible during the early phase of the treatment. However, its application is currently limited because the bond strength between the 3D-printable DBR and metal may weaken after short-term use. Further studies on methods to increase the bond strength between these heterogeneous materials are required.

Influence of Five Different Commercially Available Mouthwashes on the Growth of Candida albicans Adhered to Customized Prefabricated Heat-Cured Denture Base Acrylic Resin Sheets: An In Vitro Study.

Background The purpose of this in vitro investigation was to evaluate the impact of five distinct commercial mouthwashes on the development of Candida albicans that had been adhered to heat-cured acrylic resin sheets. Methods This in vitro investigation was carried out at the MES Medical College's Microbiology Department in Perinthalmanna, Kerala, India. A total of 72 heat-cured acrylic resin sheets, size 10 × 10 × 2 mm, were fabricated. After disinfection, all 72 acrylic sheets were placed in a flask containing a suspension of the standard strain of Candida species (American Type Culture Collection) and incubated at 37ºC for 24 hours. Then, the acrylic sheets were randomly divided into six groups, with each group containing 12 acrylic sheets. Group 1 was the control group to which no mouthwash was added. In group 2, Colgate Plax was added. In group 3, Hiora Himalaya was added. In group 4, Oral B was added. In group 5, Listerine was added. In group 6, Pepsodent was added. Colony-forming units (CFUs) were assessed using a colony counter every six, 24, 48, and 120 hours. After obtaining the pH and CFU of all 72 specimens, software known as the Statistical Package for Social Sciences (SPSS) (IBM Corp., Armonk, NY) was used to analyze the data. Results Candida albicans adhered to heat-cured denture base acrylic resin sheets differed significantly in response to commercially available mouthwashes (Oral B, Colgate Plax, and Pepsodent) and non-commercial mouthwashes (Hiora Himalaya and Listerine) that contained cetylpyridinium chloride. Conclusions Compared to other mouthwashes that do not contain cetylpyridinium chloride (Listerine and Hiora Himalaya), mouthwashes with cetylpyridinium chloride as the active ingredient (Oral B, Pepsodent, and Colgate Plax) have shown good antifungal properties against the adhering Candida albicans on denture base resin.

Assessment of Adaptability and Linear Dimensional Changes of Two Heat Cure Denture Base Resin with Different Cooling Techniques: An In Vitro Study.

AIM: The current study was designed to assess the linear dimensional changes and adaptability of two heat-cured denture base resins using various cooling methods. MATERIALS AND METHODS: To prepare a total of 90 acrylic resin samples (45 acrylic resin samples for each material), four rectangular stainless-steel plates measuring 25 × 25 × 10 mm were fabricated. For both groups, the material was put into the mold at the dough stage. Group I - SR Triplex Hot Heat Cure acrylic; group II - DPI Heat Cure acrylic. Both groups used the same curing procedure. One of the following three techniques was used to cool the material (15 samples from each material) once the curing cycle was finished: (A) water bath, (b) quenching, and (C) air. A traveling microscope was used to measure the distance between the markings on the acrylic samples. The data was recorded and statistically analyzed. RESULTS: In SR Triplex Hot heat cure acrylic material, the maximum linear dimensional changes were found in the quenching technique (0.242 ± 0.05), followed by the air technique (0.168 ± 0.11) and the least was found in the water bath technique (0.146 ± 0.01). In DPI Heat Cure acrylic material, the maximum linear dimensional changes were found in the quenching technique (0.284 ± 0.09), followed by the air technique (0.172 ± 0.18) and the least was found in the water bath technique (0.158 ± 0.10). There was a statistically significant difference found between these three cooling techniques. On comparison of adaptability, the water bath technique, the marginal gap SR Triplex Hot was 0.012 ± 0.02 and DPI Heat Cure was 0.013 ± 0.02. In the quenching technique, the marginal gap SR Triplex Hot was 0.019 ± 0.04 and DPI Heat Cure was 0.016 ± 0.04. In the air technique, the marginal gap SR Triplex Hot was 0.017 ± 0.01 and DPI Heat Cure was 0.019 ± 0.01. CONCLUSION: The present study concluded that among the different cooling methods, the water bath technique had the least linear dimensional change, followed by the air and quenching techniques. When comparing the materials, DPI Heat Cure acrylic resin showed a greater linear dimensional change than SR Triplex Hot heat cure acrylic resin. CLINICAL SIGNIFICANCE: During polymerization, heat-cured acrylic resins experience dimensional changes. Shrinkage and expansion are dimensional changes that occur in heat-cured acrylic resins and have an impact on the occlusal relationship and denture fit. However, the denture base's material qualities and the different temperature variations it experiences during production may have an impact on this. How to cite this article: Kannaiyan K, Rathod A, Bhushan P, et al. Assessment of Adaptability and Linear Dimensional Changes of Two Heat Cure Denture Base Resin with Different Cooling Techniques: An In Vitro Study. J Contemp Dent Pract 2024;25(3):241-244.

Color and flexural properties of nanoparticles-modified denture base resin: An in vitro comparative study.

Objectives: Reinforcement of polymethylmethacrylate (PMMA) denture base resins (DBRs) with inorganic fillers with superior properties and accepted aesthetics are favored and still a big dilemma. This study was undertaken to evaluate the color change, flexural strength, and modulus of elasticity of heat-polymerized DBR material modified with silver nanoparticles (AgNPs) and zirconium dioxide nanoparticles (ZNPs). Methods: Sixty acrylic specimens (30/color test, 30/flexural properties) were fabricated and divided according to nanoparticles type and addition into 3 groups (n = 10). Group-I; unmodified specimens, Group-II; modified specimens with 0.5wt% AgNPs (PMMA/AgNPs), and Group-III; modified specimens with 7.5wt% ZNPs (PMMA/ZNPs). Disc-shape (20 × 3 mm) and bar-shape (65 × 10 × 2.5 mm) specimens were fabricated for color and flexural properties, respectively. The spectrophotometer was used for evaluation of the color change (∆E). The flexural strength and elastic modulus evaluation was carried out using a 3-point bending test (5 mm/min). Tukey's post hoc and one-way ANOVA were used to analyze the data at a significant level P ≤ 0.05. Results: PMMA/AgNPs group exhibited a significant increase in color change when compared with PMMA/ZNPs. PMMA/ZNPs showed significantly the highest flexural strength value when compared with unmodified and PMMA/AgNPs groups (P < 0.001), however, there was an absence of significant differences in terms of flexural strength values between PMMA/AgNPs and unmodified groups (P > 0.05). PMMA/AgNPs insignificantly increased its modulus of elasticity strength (P = 0.09410) while PMMA/ZNPs significantly increased its modulus of elasticity strength (P = 0.00396). Conclusion: The AgNPs and ZNPs addition to PMMA increased the color change and AgNPs change the color of DBRs. The flexural attributes of DBRs have been increased by ZNPs.

Microbial Adhesion to Different Thermoplastic Denture Base Materials in Kennedy Class I Partially Edentulous Patients.

Introduction Since the polished and fitting surface of the denture base may promote the colonization of microorganisms, it is essential to know how the different types of denture bases prevent or encourage the adhesion of microorganisms. This study aimed to compare the microbial adhesion to the polished and fitting surfaces of thermoplastic nylon, thermoplastic acetal, and thermoplastic acrylic denture bases in Kennedy Class Ⅰ, partially edentulous patients. Materials and methods Thirteen patients were included in the study. The group consisted of eight males (61.54%) and five females (38.46%), with an age range of 41-50 years (mean age 46.1 years). Three types (groups) of removable partial dentures will be made for each patient using different thermoplastic denture base materials: thermoplastic nylon; thermoplastic acetal; and thermoplastic acrylic. The polished and fitting surfaces of the denture bases were swabbed after a one-month follow-up period. Microbial adhesion was evaluated by counting the microorganisms' colony-forming units (CFU) in the collected specimens. The data were collected and statistically analyzed. Results The study revealed no statistically significant difference in microbial adhesion to both polished and fitting surfaces between all types of studied thermoplastic denture base materials. However, the results showed that for the polished surface, the microbial adhesion median of thermoplastic acrylic denture base (40.5 CC x 102/ml) was higher than that of thermoplastic acetal (29.0 CC x 102/ml) and thermoplastic nylon (16.0 CC x 102/ml). Regarding the fitting surface, the microbial adhesion median of thermoplastic acrylic (51.0 CC x 102/ml) is higher than that of thermoplastic acetal (41.0 CC x 102/ml) and thermoplastic nylon (23.0 CC x 102/ml). Conclusion The thermoplastic nylon denture base materials showed less microbial adhesion among the studied thermoplastic materials, so it may be recommended to be used as a denture base material for individuals at high risk of denture stomatitis.

Nanoparticle-Modified 3D-Printed Denture Base Resins: Influence of Denture Cleansers on the Color Stability and Surface Roughness In Vitro.

This study aimed to evaluate the influence of denture cleansers on the color, stability, and surface roughness of three-dimensional (3D)-printed denture base resins modified with zirconium dioxide nanoparticles (nano-ZrO2). A total of 440 specimens were fabricated using one heat-polymerized resin, and two 3D-printed resins (NextDent and ASIGA). According to the nano-ZrO2 content, the specimens for each resin were divided into five groups (0%, 0.5%wt, 1%wt, 3%wt, and 5%wt). Each concentration was divided into four subgroups (n = 10) based on the immersion solution (distilled water, sodium hypochlorite, Corega, and Fittydent) and immersion duration (360 and 720 days). The color changes (∆E00) and surface roughness (Ra, µm) of each specimen were measured at different time intervals (base line, 360 days, 720 days) using a spectrophotometer and a non-contact profilometer, respectively. The results were statistically analyzed using ANOVA and a post hoc Tukey's test (α = 0.05). Sodium hypochlorite showed the highest significant color change of all the denture base resins (p < 0.001). The average value of ΔE00 for sodium hypochlorite was significantly higher than the values for the other solutions (Fittydent, Corega, and water) (p < 0.001). Color stability was significantly affected by immersion time for all types of solutions except Corega (p < 0.001). All of the tested immersion solutions (distilled water, sodium hypochlorite, Corega, and Fittydent) showed a significant increase in the surface roughness of all the denture base resins (p < 0.05). Surface roughness was substantially increased by immersion time for all types of solution except Fittydent (p < 0.001). Denture cleansers can result in substantial color change and affect the surface roughness of unmodified and nanoparticle-modified denture base resins. Therefore, the selection of denture cleanser and appropriate types of material is critical for denture longevity.

Mapping the research landscape of nanoparticles and their use in denture base resins: a bibliometric analysis.

BACKGROUND: Nanoparticles are increasingly used in dentistry for various applications, including enhancing the mechanical properties of denture base resins. This study aimed to comprehensively review and analyze the research landscape of nanoparticles and their effect on the flexural strength of denture base resins to identify key research areas and trends and to highlight the importance of collaboration between authors and institutions. METHODS: A Bibliometric Analysis was conducted using the Keywords "Nanoparticle*" AND "Denture*" OR "CAD/CAM." The literature search from the WOS database was restricted to the publication years 2011 to 2022. RESULTS: Key findings encompass an increase in research publications but a decline in citations. Saudi Arabia, China, and Iraq led this research, with specific institutions excelling. Notable journals with high impact factors were identified. Authorship patterns show variations in citation impact. Additionally, keyword analysis revealed that current research trends offer insights into influential authors and their networks. CONCLUSIONS: The analysis of nanoparticles and denture base resins reveals a dynamic and evolving landscape that emphasizes the importance of collaboration, staying current with research trends, and conducting high-quality research in this ever-evolving domain.

Antimicrobial activity of cleanser tablets against S. mutans and C. Albicans on different denture base materials.

BACKGROUND: In this study, the antimicrobial activity of three different cleanser tablets on S. mutans and C. albicans adhesion to PMMA, polyamide and 3D printed resin was investigated. METHODS: 40 samples were prepared for PMMA (SR Triplex Hot), polyamide (Deflex) and 3D printed resin (PowerResins Denture) materials and divided into four subgroups for cleansers (Aktident™, Protefix™, Corega™ tablets and distilled water) (n = 5). After the surface preparations were completed, the samples were immersed separately in tubes containing the prepared microorganism suspension and incubated at 37˚C for 24 h. After the incubation, the samples were kept in the cleanser solutions. The samples were then transferred to sterile saline tubes. All the tubes were vortexed and 10 µl was taken from each of them. Sheep blood agar was inoculated for colony counting. The inoculated plates were incubated for 48 h for S. mutans and 24 h for C. albicans. After incubation, colonies observed on all plates were counted. Statistical analyses were done with three-way ANOVA and Tukey's multiple comparison test. RESULTS: Polyamide material registered the highest colony count of S. mutans, whereas PMMA registered the lowest. Significant differences in S. mutans adherence (p = 0.002) were found between the three denture base materials, but no such difference in C. albicans adherence (p = 0.221) was identified between the specimens. All three cleanser tablets eliminated 98% of S. mutans from all the material groups. In all these groups, as well, the antifungal effect of Corega™ on C. albicans was significantly higher than those of the other two cleanser tablets. CONCLUSIONS: According to the study's results, it may be better to pay attention to surface smoothness when using polyamide material to prevent microorganism retention. Cleanser tablets are clinically recommended to help maintain hygiene in removable denture users, especially Corega tablets that are more effective on C. albicans.

[Effect of printing orientation on physical and mechanical properties of 3D printing prosthodontic base resin materials].

OBJECTIVE: To analyze the influence of forming direction on the surface characteristics, elastic modulus, bending strength and fracture toughness of printed parts and the relationship between forming direction and force direction, and to provide scientific basis and guidance for the clinical application of oral denture base resin materials. METHODS: The 3D printing technology was used to print denture base resin samples. The shape and size of the samples referred to the current standard for testing conventional denture base materials. The samples used for physical performance testing were cylindrical (with a diameter of 15 mm and a thickness of 1 mm) and printed at different angles along the Z axis (0°, 45°, 90°). Scanning electron microscope was used to observe the microscopic topography of the different samples. The color stability of different samples was observed by color stabilizer. The surface roughness of the samples was analyzed by using surface roughness tester. The Vickers hardness was measured to analyze the hardness of the samples. The samples used for mechanical performance testing were rectangular (elastic modulus and bending strength: A length of 64 mm, a width of 10 mm, and a height of 3.3 mm; fracture toughness: A length of 39 mm, a width of 8 mm, and a height of 4 mm), divided into two groups: W group and H group. The W group was printed from the bottom up along the Z axis with the length × width as the bottom surface parallel to the X, Y axis plane, while the H group printed from the bottom up along the Z axis with the length × height as the bottom surface parallel to the X, Y axis plane. The forming angles of both groups were equally divided into 0°, 45°, and 90°. The elastic modulus, bending strength and fracture toughness of different samples were studied through universal mechanical testing machine. SPSS 22.0 software was used for statistical analysis. RESULTS: The microscopic topography and roughness of different samples were closely related to the printing direction, with significant differences between the 0°, 45°, and 90° specimens. The 0° specimens had the smoothest surface (roughness < 1 µm). The surface of the 45° specimen was the roughest (roughness>3 µm). The microhardness of the 0° sample was the best [(196.13±0.20) MPa], with a significant difference compared with the 90° sample [(186.62±4.81) MPa, P < 0.05]. The mechanical properties of different samples were also closely related to the printing direction. The elastic modulus, bending strength, and fracture toughness of the 45° samples in the W group were the highest compared with the other groups. The results of elastic modulus showed that in the H group, the 45° specimens had the highest elastic mo-dulus, which was significantly different from the 0° and 90° specimens (P < 0.05). The elastic modulus of 0° and 45° specimens in the W group were higher than those in 90° specimens (P < 0.05). The bending strength results showed that there was no significant difference between the specimens from dif-ferent angles in the H group. The bending strength of the 90° specimens in the W group was the smallest, and there was a significant difference between 90° and the 0° and 45° specimens (P < 0.05); And the bendind strength of the 0° and 45° specimens in the W group was significantly higher than that of the 0° and 45° specimens in the H group (P < 0.05). The fracture toughness results showed that the fracture toughness of the H group specimens was lower than 1.9 MPa m1/2, which was specified in the denture base standard. The 45° samples in the W group were the highest, with significant differences compared with the 0° and 90° samples (P < 0.05). And the 90° samples of the W group specimens were lower than 1.9 MPa m1/2. And the fracture toughness of the 45° specimen in the W group was significantly higher than that of all the specimens in the H group (P < 0.05). CONCLUSION: The 0° samples had relatively better physical properties. The 45° samples had the best mechanical properties. But the fracture toughness of specimens (H group and 90° samples of W group) did not yet meet clinical requirements. That indicated that the characteristics of the 3D printing denture base resin were affected by the printing direction. Only when the performance of the printed samples in all directions met the minimum requirements of the standard, they could be used in clinical practice.