Biocompatibility of a titanium dioxide-coating method for denture base acrylic resin

Tendency of microbial adhesion to denture base resins: a systematic review

Objectives

Digital denture fabrication became an alternative method to conventional denture fabrication. However reviewing the antimicrobial performance of newly introduced digital fabrication methods in comparison to the conventional method is neglected. Aim of study: this review was to compare the antiadherence properties of various CAD-CAM subtractive (milled), additive (3D printed) conventional denture base resins. In order to answer the developed PICO question: "Does CAD-CAM milled and 3D printed denture base resins have microbiological antiadherence properties over the conventional ones?" We included comparative studies on digitally fabricated Denture base resins with conventionally fabricated one in term of microbial adhesion.

Methods

All in vitro studies investigated the microbial adherence to CAD-CAM milled and 3D printed denture base resins in comparison to conventional were searched in the PubMed, Web of Sciences, and Scopus databases up to December 2023.

Results

Fifteen studies have been investigated the microbial adhesion to milled and 3D printed denture base resins. CAD-CAM milled resins significantly decreased the microbial adhesion when compared with the conventional resins and 3D printed resins, while the later showed a high tendency for microbial adhesion. The addition of antifungal agents to 3D printed resins significantly reduced C. albicans adhesion. In terms of 3D printing parameters, printing orientation affected adherence while printing technology had no effect on microbial adhesion.

Conclusion

Denture base materials and fabrication methods significantly affect the microbial adhesion. CAD-CAM milled denture base resins demonstrated low microbial adhesion. 3D-printed resins showed high tendency for C. albicans adhesion. The antiadherent properties of 3D-printed resins can be improved by incorporating antifungal agents or changing the printing parameters, but further investigations are required to validate these modifications.

Influence of apigenin and seashell nanoparticles on the biological attitude of soft denture liner

Objective

To determine the "biocompatibility" of a soft denture liner impregnated with apigenin and seashell nanoparticles via histopathological assessment in rabbit models.

Materials and Methods

Twenty-six albino rabbits aged 5-7 months and weighing, 1.25-1.5 kg were randomly divided into apigenin and seashell-modified groups, n = 13 each). A total of 104 disc-shaped specimens (3 mm thick and 5 mm in diameter) of a heat-cured soft liner, (GC, USA) were prepared. In the apigenin group, each rabbit was subcutaneously implanted with 4 specimens: (positive control, unmodified-liner, and 0.25 %, 0.5 %, and 1 % of apigenin-modified liner). In the seashell group, rabbits were implanted with positive control and 1.25 %, 2.5 % and 5 % seashell-modified liner. A non-implanted incision was performed for all the groups as a negative control. Histopathological observations were evaluated according to inflammatory and angiogenesis scores 14 days after implantation.

Results

A significant decrease in inflammatory responses and an increase in angiogenesis were observed for both apigenin and seashell-modified soft liner groups. Higher compatibility effectiveness was positively related to and recorded in the increased ratios of nanoparticles within the soft liner material.

Conclusion

Apigenin and seashell-modified soft liners at higher ratios 1% and 5% respectively were more compatible with the rabbit mucosa.

Denture Base Resin Coated with Titanium Dioxide (TiO2): A Systematic Review

Background

The main objective of this systematic review was to evaluate the effect of coating with titanium dioxide nanoparticles (TiO2 nanoparticle) on the surface condition of removable acrylic resin prosthetic base materials.

Methods

Our review is registered in the PROSPERO database under the identification code CRD42023397170. Electronic database searches of PubMed, Scopus and Science Direct including studies from January 2009 to January 2023 were conducted and supplemented with manual searches. Research questions were generated in accordance with the PICO strategy. The modified Consolidated Standards of Reporting Trials (CONSORT) checklist was used to evaluate the quality of the selected studies.

Results

Since the included studies were variable in design, a meta-analysis was not performed. The electronic searches retrieved 29 references that met the eligibility criteria, among which 5 studies matched the inclusion criteria for this review. Significant differences were detected between the TiO2 NP-coated and uncoated groups. The available data indicate that TiO2 NP coating elicits antimicrobial activity and improves the wear resistance of polymethylmethacrylate (PMMA) surfaces. Moreover, the nanoparticles provide high levels of glossiness and decelerate the process of color change of heat-cured acrylic resin, thus increasing the lifespan of dentures.

Conclusion

The collective results clearly indicate that TiO2 nanoparticle coating induces alterations in the surface properties of pure PMMA, enhancing the mechanical, physical and biological characteristics of the denture base material. Further studies are essential to identify the optimal thickness of coating and concentrations of nanoparticles for clinical applications.

Effect of denture cleansers on color stability and surface properties of denture base material containing titanium dioxide nanoparticles

PURPOSE

To investigate the effect of different denture cleansers on color stability, surface roughness, and hardness of polymethylmethacrylate (PMMA) infused with titanium dioxide nanoparticles (TiO2 NPs) at concentrations of 1% and 2% by weight on each.

MATERIALS AND METHODS

In this in vitro study, 90 disc-shaped specimens (10×10×2 mm) were divided into 3 main groups: the non-containing nanoparticle group (0wt% concentration), 1wt% concentration, and 2wt% concentration TiO2 NPs groups. Each group was further assorted into 3 subgroups (n = 10): immersed in distilled water, oxygenating tablet (Corega), and 0.5% sodium hypochlorite. Color change, surface roughness, and hardness values were assessed after 90 and 180 days of storage. Color changes (∆E) were measured with a spectrophotometer (VITA, Easy Shade V, Germany) and assessed using the CIE L*a*b* colorimetric system and the American National Bureau of Standards (NBS = 0.92×∆E). The surface roughness and surface hardness values were measured using a profilometer device and Vickers hardness tester, respectively. First, ANOVA-repeated measurements were performed, followed by the Tukey test. The significance level in this study was considered 0.05.

RESULTS

At all concentrations, there were significant differences in the mean color changes of samples immersed in cleansers compared to distilled water (p < 0.01). Moreover, hypochlorite caused a significant increase compared to Corega at 0wt% concentration after 90 days and at 1wt% concentration after 90 and 180 days. Evaluations also showed that the mean NBS values in all cleanser groups were in the range of appreciable change, except the water group. In addition, only hypochlorite changed the color higher than the clinically acceptable range (∆E >3.7). The mean roughness of samples immersed in hypochlorite at 0wt% concentration was significantly higher than the samples containing TiO2 NPs (p = 0.006). No significant difference was observed in surface roughness of samples containing different concentrations of TiO2 NPs immersed in different cleansers; however, hypochlorite increased the surface roughness of samples without TiO2 NPs compared to samples containing TiO2 NPs after 180 days. The immersion time in cleansers had a significant influence on the surface roughness and hardness while having no effect on the color.

CONCLUSION

In general, the cleansers had a significant effect on color change in all groups compared to distilled water. The adverse effect of hypochlorite was more than Corega. The cleansers in the samples containing TiO2 NPs did not make a significant difference in surface roughness in comparison with the distilled water groups. Surface hardness of the samples was not affected in a steady pattern by the cleansers.

3D-printed nanocomposite denture base resin: The effect of incorporating TiO2 nanoparticles on the growth of Candida albicans

PURPOSE

To develop a biocompatible denture base resin/TiO2 nanocomposite material with antifungal characteristics that is suitable for 3D-printing denture bases.

MATERIALS AND METHODS

TiO2 nanoparticles (NPs) with a 0.10, 0.25, 0.50, and 0.75 weight percent (wt.%) were incorporated into a commercially available 3D-printed resin material. The resulting nanocomposite material was analyzed using Lactate dehydrogenase (LDH) and AlamarBlue (AB) assays for biocompatibility testing with human gingival fibroblasts (HGF). The composite material was also tested for its antifungal efficacy against Candida albicans. Fourier transform infrared (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX) mapping were conducted to assess the surface coating and the dispersion of the NPs.

RESULTS

LDH and AB assays confirmed the biocompatibility of the material showing cell proliferation at a rate of nearly 100% at day 10, with a cytotoxicity of less than 13% of the cells at day 10. The concentrations of 0.10, 0.25, and 0.50 wt.% caused a significant reduction (p < 0.05) in the number of candida cells attached to the surface of the specimens (p < 0.05), while 0.75 wt.% did not show any significant difference compared to the control (no TiO2 NPs) (p > 0.05). FTIR and EDX analysis confirmed the presence of TiO2 NPs within the nanocomposite material with a homogenous dispersion for 0.10 and 0.25 wt.% groups and an aggregation of the NPs within the material at higher concentrations.

CONCLUSION

The addition of TiO2 NPs into 3D-printed denture base resin proved to have an antifungal effect against Candida albicans. The resultant nanocomposite material was a biocompatible material with HGFs and was successfully used for 3D printing.

Effect of addition of titanium dioxide nanoparticles on the antimicrobial properties, surface roughness and surface hardness of polymethyl methacrylate: A Systematic Review

Background: Polymethyl Methacrylate (PMMA) denture-base resins have poor surface properties that facilitates microbial adhesion causing denture stomatitis. This systematic review aims to evaluate the effect of different sizes and percentages of titanium dioxide nanoparticles (TiO2NP) on the antimicrobial property, surface roughness and surface hardness of PMMA denture base resin.  Methods: A systematic search of English peer-reviewed articles, clinical trial registries, grey literature databases and other online sources was performed using the PRISMA-S Guidelines for In-Vivo and In-Vitro studies. Qualitative data synthesis was performed to analyse sample dimensions, acrylic used, treatments of nanoparticles, methods used for testing and effect of size and percentage of nanoparticle. Risk of bias assessment was done using modified Cochrane risk of bias tool. Results: Out of 1376 articles, 15 were included. TiO 2NP of size less than 30 nm was most frequently used. Both antimicrobial property and surface hardness improved irrespective of the size of the added TiO 2NP. Three studies reported increase in the surface roughness with less than 50 nm TiO 2NP.  3% TiO 2NP was most frequently used. On increasing the percentage, three studies reported an increase in antimicrobial property, while two studies found no change. With TiO 2NP greater than or equal to 3%, six studies reported an increase in surface hardness, while two reported increase in surface roughness. Large methodological variations were observed across studies. All studies except one were of moderate quality. Conclusions:   On addition of TiO 2NP to heat polymerized PMMA, the antimicrobial property and surface hardness improved irrespective of the size of the TiO 2NP, however, addition of nanoparticles less than 50 nm increased the surface roughness. Increasing the percentage of TiO 2NP increased the surface hardness but did not always increase the antimicrobial property. Addition of 3% TiO 2NP provided optimum results with regards to antimicrobial effect and surface hardness, but increase in the surface roughness.

The stain resistant effect of an ultraviolet curable coating material on denture base resin

This study aimed to evaluate the effects of an ultraviolet (UV) curable coating material on denture base resin. The results of the three-point bending test showed no significant difference between treated and untreated specimens, suggesting that the UV curable coating material did not compromise the physical strength of denture base resin. The surface free energy measurement and the surface analysis with atomic force microscopy revealed superhydrophilicity and a regularly arranged structure on the coating surface, improving wettability. Moreover, untreated specimens were significantly discolored in the staining test. However, specimens treated with the UV curable coating material showed no significant difference in color with slight staining, suggesting excellent antifouling ability. Therefore, the UV curable coating material used in this study could contribute to simplifying hygiene without altering the physical properties of denture base resins.

Effect of Nano Ceramic Coating on Color Perceptibility and Acceptability of Polymethylmethacrylate: In Vitro and Clinical Study

The effect of a novel nano-ceramic coating (TiO₂) using an atomic layer deposition (ALD) technique on the surface of polymethyl methacrylate (PMMA) material was investigated. The patients' and clinicians' perception and acceptance of the PMMA color with TiO₂ coating were also examined. In vitro color measurement was performed on thirty specimens (light, original, and dark pink) before and after TiO₂ coating. Patients' and clinicians' perception and acceptance of color changes on PMMA were measured and compared. Descriptive and analytic statistics were analyzed (a = 0.05). TiO₂ films were successfully deposited on the PMMA specimen by the ALD technique. Color changes after TiO₂ coating were observed on all three PMMA shades, significantly higher than the established 50:50% perceptibility threshold, but below the established 50:50% acceptability threshold. The percentage of patients that perceived a color difference after TiO₂ coating were 83.3%, 63.9%, and 77.8% for light, original, and dark pink, respectively. The percentages of clinicians that were satisfied with the color difference were 96.4%, 80%, and 69.2% for light, original, and dark pink, respectively. Color changes after TiO₂ coating were observed, but below the acceptable threshold. The clinical survey demonstrated that a color difference was perceived but was clinically acceptable. In general, laypeople have lower perception and higher acceptance of changes in PMMA color than clinicians.

Modification of Polymer Based Dentures on Biological Properties: Current Update, Status, and Findings

Polymers remain an integral part of denture fabrication materials, specifically polymethylmetacrylate (PMMA). PMMA has been extensively used, particularly in construction as a denture base material. Nonetheless, various challenges, including microbial threats in the form of candidiasis occurrence, still remain a biological challenge to denture wearers. The present article comprehensively reviews the biomodifications introduced to denture components, in particular denture base material, to improve the overall biological properties, together with physical, mechanical, structural integrity, and optical properties. In addition, fundamental information specifically to PMMA as a conventional denture base material and the causative aetiological microbial agents for biological threat to dentures are explored.

Antimicrobial Activity of Thermocycled Polymethyl Methacrylate Resin Reinforced with Titanium Dioxide and Copper Oxide Nanoparticles

Aims

This study aimed to evaluate the effect of 2.5% and 7.5% copper oxide (CuO) and titanium dioxide (TiO₂) nanoparticles on the antimicrobial activity of thermocycled polymethyl methacrylate (PMMA) denture base material against standard strains of yeast and bacteria species. Material and Methods. In this in vitro study, 150 disk-shaped (10 × 2 mm) specimens of heat-cured PMMA were prepared and divided into five groups (n = 30) to be reinforced with 2.5% CuO, 7.5% CuO, 2.5% TiO₂, or 7.5% TiO₂ nanoparticles and a control group (without nanoparticle). The specimens were thermocycled, and their antimicrobial activity was assessed against standard strains of yeast including Candida albicans and C. dubliniensis and oral bacteria species including Streptococcus mutans, S. sobrinus, S. salivarius, and S. sanguis. Data were analyzed with ANOVA and Tukey's post hoc tests (α = 0.05).

Results

Both concentrations of CuO and TiO₂ nanoparticles had significant antimicrobial activity against S. salivarius, S. sanguis, and C. dubliniensis compared with the control group (P < 0.05). Significant differences existed between both 2.5% (P = 0.006) and 7.5% CuO (P = 0.005) and the control group against S. mutans. However, TiO₂ groups were not significantly different from the control group against S. mutans. Concerning C. albicans, 7.5% TiO₂ was the only nanoparticle with significantly higher antimicrobial activity compared with the control group (P = 0.043).

Conclusions

Both concentrations of CuO and TiO₂ were effective antimicrobial agents against S. salivarius, S. sanguis, and C. dubliniensis, and the concentration of CuO was effective against S. mutans. Yet, TiO₂ was not much effective. Regarding C. albicans, only 7.5% TiO₂ showed efficient antimicrobial activity.

3D printed complete removable dental prostheses: a narrative review

Background

The purpose of this paper is to review the available literature on three-dimensionally printed complete dentures in terms of novel biomaterials, fabrication techniques and workflow, clinical performance and patient satisfaction.

Methods

The methodology included applying a search strategy, defining inclusion and exclusion criteria, selecting studies and forming tables to summarize the results. Searches of PubMed, Scopus, and Embase databases were performed independently by two reviewers to gather literature published between 2010 and 2020.

Results

A total of 126 titles were obtained from the electronic database, and the application of exclusion criteria resulted in the identification of 21 articles pertaining to printed technology for complete dentures. Current innovations and developments in digital dentistry have successfully led to the fabrication of removable dental prostheses using CAD/CAM technologies. Milled dentures have been studied more than 3D printed ones in the currently available literature. The limited number of clinical studies, mainly case reports, suggest current indications of 3D printing in denture fabrication process to be custom tray, record bases, trial, interim or immediate dentures but not definitive prostheses fabrication. Limitations include poor esthetics and retention, inability to balance occlusion and low printer resolution.

Conclusions

Initial studies on digital dentures have shown promising short-term clinical performance, positive patient-related results and reasonable cost-effectiveness. 3D printing has potential to modernize and streamline the denture fabrication techniques, materials and workflows. However, more research is required on the existing and developing materials and printers to allow for advancement and increase its application in removable prosthodontics.

Double-layered acrylic resin denture base with nanoparticle additions: An in vitro study

STATEMENT OF PROBLEM

Whether the addition of different antifungal nanoparticles to denture base materials may affect physical or esthetic properties of the resulting nanocomposite is unclear.

PURPOSE

The purpose of this in vitro study was to determine how a new method of adding antifungal nanofiller affects the properties of the processed nanocomposite denture base material.

MATERIAL AND METHODS

Heat-polymerized acrylic resin specimens were prepared according to each test specification. Zirconium dioxide nanoparticles (ZrO₂NPs) and silver nanoparticles (AgNPs) were added in 0.5, 1.0, and 1.5% of acrylic resin powder. The specimens were divided into 2 groups according to the acrylic resin packing method: 1 layer packed conventionally in one step and 2 layers packed in 2 steps, first with unmodified acrylic resin and then by a thin layer of modified acrylic resin before the final closure. The control group was made of unaltered acrylic resin in 1 step. Flexural strength (FS), translucency, and surface roughness (R_a) were measured. A microbial assay was performed by using the direct culture and slide count methods. Three-way ANOVA and Tukey post hoc tests were used to identify statistical differences among groups (α=.05).

RESULTS

The addition of ZrO₂NPs and AgNPs in the 1- or 2-layer specimens reduced Candida albicans adhesion (P<.001). In the 1- and 2-layer specimens, FS significantly increased with ZrO₂NPs. AgNPs decreased FS only in the 1-layer specimen (P<.001). Surface roughness was not changed for the 1- and 2-layer specimens with ZrO₂NPs or the 1-layer specimen with 0.5% AgNPs (P>.05), while other AgNP groups exhibited increased surface roughness (P<.001). AgNPs significantly lowered translucency in the 1- and 2-layer specimens (P<.001), while ZrO₂NPs decreased translucency only in the 1-layer specimen (P<.001).

CONCLUSIONS

The addition of ZrO₂NPs in the double-layer technique decreased Candida adhesion and improved FS without affecting surface roughness, while AgNPs decreased Candida adhesion and FS and increased surface roughness. Both nanofillers decreased the translucency except 0.5% ZrO₂NPs, which did not change translucency when applied in 2 layers.

Preparation and Characterisation of Poly(methyl metacrylate)-Titanium Dioxide Nanocomposites for Denture Bases

Introduction of titanium dioxide nanoparticles (TiO₂ NPs) to poly(methyl methacrylate) (PMMA) aims to improve the mechanical, microbiological and tribological properties of dental prosthesis bases. The aim of the research was to assess the polymerisation time and the change in the colour of the new biomaterial. Samples with the 1 wt% and 2 wt% content of TiO₂ additionally modified by ultrasounds were created. The effectiveness of ultrasounds was assessed by comparing the average size of conglomerates in a liquid acrylic resin monomer by means of a dynamic light scattering (DLS) analysis. The biomaterial structure was assessed by the energy-dispersive X-ray spectroscopy (EDS) analysis. The colour change was analysed by means of a colorimetric test and provided in the CIE (Commission internationale de l’éclairage) L*a*b* and RGB (Red Green Blue) colour palette. It was observed during the DLS test that the ultrasonic homogenisation process caused an increase in the suspension heterogeneity. The EDS analysis confirmed the presence of nanoparticles sized below 100 nm, which constitutes a ground for calling the new biomaterial a nanocomposite. The addition of TiO₂ NPs as well as the ultrasounds result in the reduction of the average PMMA polymerisation time. The obtained data reveal that the addition of both 1 wt% and 2 wt% causes a considerable change in the PMMA colour: its whitening. To summarise, the reduced polymerisation time of the new biomaterial fully enables performance of standard procedures related to creation of dental prosthesis bases. Due to the considerable change in the colour, the clinical application is limited to performance of repairs or relining of the prosthesis, where the new material is located in an unaesthetic zone.

Polymeric and inorganic nanoscopical antimicrobial fillers in dentistry

Failure of dental treatments is mainly due to the biofilm accumulated on the dental materials. Many investigations have been conducted on the advancements of antimicrobial dental materials. Polymeric and inorganic nanoscopical agents are capable of inhibiting microorganism proliferation. Applying them as fillers in dental materials can achieve enhanced microbicidal ability. The present review provides a broad overview on the state-of-the-art research in the field of antimicrobial fillers which have been adopted for incorporation into dental materials over the last 5 years. The antibacterial agents and applications are described, with the aim of providing information for future investigations. STATEMENT OF SIGNIFICANCE: Microbial infection is the primary cause of dental treatment failure. The present review provides an overview on the state-of-art in the field of antimicrobial nanoscopical or polymeric fillers that have been applied in dental materials. Trends in the biotechnological development of these antimicrobial fillers over the last 5 years are reviewed to provide a backdrop for further advancement in this field of research.

Behavior of PMMA Denture Base Materials Containing Titanium Dioxide Nanoparticles: A Literature Review

Titanium dioxide nanoparticles (TiO₂NP) have gained interest in the dental field because of their multiple uses in addition to their antimicrobial effect. One of the applications in dentistry involves the incorporation into poly methyl methacrylate (PMMA) resin. However, there is a lack of evidence on their effects on the behavior of the resulting nanocomposite. Therefore, the present review aims to screen literatures for data related to PMMA/TiO₂ nanocomposite to figure out the properties of TiO₂ nanoparticles, methods of addition, interaction with PMMA resin matrix, and finally the addition effects on the properties of introduced nanocomposite and evidence on its clinical performance. Regardless of the latest research progress of PMMA/TiO₂ nanocomposite, the questionable properties of final nanocomposite and the lack of long-term clinical evidence addressing their performance restrict their wide clinical use. A conclusive connection between nanoparticle size or addition method and nanocomposite properties could not be established.

Blue-Light -Activated Nano-TiO2@PDA for Highly Effective and Nondestructive Tooth Whitening

The application of polydopamine (PDA)-modified titanium dioxide nanoparticles (nano-TiO₂@PDA) as a new blue-light-activated tooth whitening material was discussed for the first time. Compared with the classical clinical whitening agent (peroxide, hydrogen peroxide, and carbamide peroxide), nano-TiO₂@PDA-based treatment not only had a similar whitening effect but also showed remarkably less damage on the enamel structure. Essentially, a highly effective and nondestructive tooth whitening treatment could thus be realized accordingly. The toxicity and antibacterial properties of this material were also evaluated systematically.

Antibacterial, Hydrophilic Effect and Mechanical Properties of Orthodontic Resin Coated with UV-Responsive Photocatalyst

Photocatalysts have multiple applications in air purifiers, paints, and self-cleaning coatings for medical devices such as catheters, as well as in the elimination of xenobiotics. In this study, a coating of a UV-responsive photocatalyst, titanium dioxide (TiO₂), was applied to an orthodontic resin. The antibacterial activity on oral bacteria as well as hydrophilic properties and mechanical properties of the TiO₂-coated resin were investigated. ultraviolet A (UVA) (352 nm) light was used as the light source. Antibacterial activity was examined with or without irradiation. Measurements of early colonizers and cariogenic bacterial count, i.e., colony forming units (CFU), were performed after irradiation for different time durations. Hydrophilic properties were evaluated by water contact angle measurements. While, for the assessment of mechanical properties, flexural strength was measured by the three-point bending test. In the coat(+)light(+) samples the CFU were markedly decreased compared to the control samples. Water contact angle of the coat(+)light(+) samples was decreased after irradiation. The flexural strength of the specimen irradiated for long time showed a higher value than the required standard value, indicating that the effect of irradiation was weak. We suggest that coating with the ultraviolet responsive photocatalyst TiO₂ is useful for the development of orthodontic resin with antimicrobial properties.

Elemental ion release and cytotoxicity of antimicrobial acrylic resins incorporated with nanomaterial

OBJECTIVES

This study evaluated the release of ions and the cytotoxicity of acrylic resins incorporated with silver vanadate decorated with silver nanoparticles (AgVO₃ ).

BACKGROUND

The inhibition of the accumulation of microorganisms on the resins is critical in preventing diseases. However, the hypothesis is that the release of ions from the incorporation of AgVO₃ may be important in biocompatibility.

MATERIALS AND METHODS

Specimens of autopolymerising (AP) and heat-polymerising resin (HP) with AgVO₃ were prepared and immersed in culture medium. The release of silver ions (Ag) and vanadium (V) was evaluated by mass spectrometry with inductively coupled plasma (ICP-MS) (n=9) and the cell viability of fibroblasts L929 by MTT (3-[4,5-dimethylthiazol- 2yl]-2,5-diphenyltetrazolium bromide) (n=12). The results were evaluated with analysis of variance (ANOVA), Tukey and Pearson correlation test (α=.05).

RESULTS

The groups containing AgVO₃ presented a difference in relation to the control (0%) regarding the release of Ag and V (P<.0001). All groups showed a reduction in L929 viability when compared with the cellular control (100%) (P<.0001). In comparison with the control resins for HP, a reduction in the metabolism of cells occurred starting at 2.5% and for AP at 5% (P<.0001). A positive correlation was found between the concentration of AgVO₃ and the ion release, and a negative between the ion release and the cell viability.

CONCLUSIONS

Significant numbers of Ag and V ions were released from resins with higher concentrations of AgVO₃ , presenting cytotoxicity for cells, suggesting that the use of low concentrations is indicated to avoid risks to patients.

Inhibition of denture plaque by TiO2 coating on denture base resins in the mouth

STATEMENT OF PROBLEM

Information is lacking about antiadhesion effect of titanium dioxide (TiO₂) coating on denture base resins in the mouth.

PURPOSE

The purpose of this clinical study was to investigate the antiadhesion effect of TiO₂ coating on denture base resins.

MATERIAL AND METHODS

Ten healthy dentate participants (mean 27 ±2 years of age) participated in this study. Disks and palatal appliances were made with denture base resin. They were divided into 2 groups: a TiO₂-coated group and an uncoated group. A primer and a top coat containing TiO₂ were applied to the surfaces of the resin by means of an air spray. In the denture plaque staining test, resin disks were fixed to the retainer, placed in each participant's mouth for 3 days, and stained with a dental plaque-disclosing solution. The staining rate was calculated. The resin disks and palatal appliances were used to measure the total number of microbes. The resin specimens were placed in each participant's mouth for either 3 or 7 days and swabbed to count the total number of microbes. The chewing gum adherence test was performed both subjectively and objectively. Subjectively, each participant wearing a palatal appliance rated adherence using a visual analog scale. The objective test was performed with a chewing gum adhesion test. The staining rate, the total number of microbes, and the visual analog scale values were statistically analyzed using the Wilcoxon signed rank test, and the adhesive force was statistically analyzed using a Student t test.

RESULTS

In the denture plaque staining test, the measurement of microbes, and the resin chewing gum adherence test results, significant differences were observed between the TiO₂-coated groups and the uncoated groups.

CONCLUSIONS

TiO₂ coating of the denture base acrylic resin inhibited the adhesion of microbes, denture plaque, and highly adhesive food.

Color and gloss evaluation of titanium dioxide coating for acrylic resin denture base

PURPOSE

We examined the clinical appearance (color, gloss, and surface roughness) of TiO(2) coating on polymethyl methacrylate (PMMA) resin dentures.

METHODS

A spraying method, using air brushes, was used to generate thin uniform TiO(2) coating. PMMA resin, primer-coated PMMA, and TiO(2)-coated PMMA (with primer) specimens were compared.

RESULTS

The Commission Internationale de l'Eclairage (CIE) color system revealed color variations between the with/without coated samples. The TiO(2)-coated PMMA specimen displayed high levels of glossiness, highlighting the efficient self-cleansing actions of the denture. The measured surface roughness decreased upon primer coating, and increased following TiO(2) coating.

CONCLUSIONS

The thin TiO(2) coating afforded high levels of glossiness while maintaining the color of the denture base material.