Effect of the Association of Nystatin with a Tissue Conditioner on its Ultimate Tensile Strength

Tissue Conditioner Incorporating a Nano-Sized Surface Pre-Reacted Glass-Ionomer (S-PRG) Filler

We aimed to evaluate the properties of a novel tissue conditioner containing a surface pre-reacted glass-ionomer (S-PRG) nanofiller. Tissue conditioners containing 0 (control), 2.5, 5, 10, 20, or 30 wt% S-PRG nanofiller or 10 or 20 wt% S-PRG microfiller were prepared. The S-PRG nanofillers and microfillers were observed using scanning electron microscopy. The ion release, acid buffering capacity, detail reproduction, consistency, Shore A0 hardness, surface roughness, and Candida albicans adhesion of the tissue conditioners were examined. The results indicated that the nanofiller particles were smaller and more homogeneous in size than the microfiller particles. In addition, Al, B, F, and Sr ions eluted from S-PRG were generally found to decrease after 1 day. Acid neutralization was confirmed in a concentration-dependent manner. The mechanical properties of tissue conditioners containing S-PRG nanofiller were clinically acceptable according to ISO standard 10139-1:2018, although the surface roughness increased with increasing filler content. Conditioners with 5-30 wt% nanofiller had a sublethal effect on C. albicans and reduced fungal adhesion in vitro. In summary, tissue conditioner containing at least 5 wt% S-PRG nanofiller can reduce C. albicans adhesion and has potential as an alternative soft lining material.

Therapeutic Role of Nystatin Added to Tissue Conditioners for Treating Denture-Induced Stomatitis: A Systematic Review

Denture-induced stomatitis (DIS) represents a pathological condition caused by ill-fitting dentures trauma, manifested as inflammation of the palatal tissue beneath the denture. The fungal infections are the principal contributory factors to DIS. Although the aetiology of DIS is multifactorial, the Candida albicans fungal infection remains the main cause. The objective of the present systematic review was to evaluate the latest literature on the addition of nystatin into the tissue conditioners (TCs) in the management of DIS. To search the published literature about “the addition of nystatin in TCs for treating DIS”, electronic databases (PubMed (National library of medicine) and Cochrane Library (Wiley)) were searched (from 1975 until December 2020) using different keywords. Various studies described the effectiveness and efficacy of incorporating nystatin into several TCs. The present systematic review reported that the addition of nystatin is beneficial, with slight or no consequences on both the mechanical and physical features of TCs. Adding nystatin to various TCs for treating DIS can be suggested.

Effect of Incorporation of Silver Nanoparticles on the Tensile Bond Strength of a Long term Soft Denture Liner

OBJECTIVES

 This study aimed at assessing the effect of the addition of silver nanoparticles (SNPs) to a silicone soft liner on its tensile bond strength to denture base resin.

MATERIALS AND METHODS

 SNPs were added to Mucopren cold cure soft liner in 0 (control), 0.5, 1, 2, and 3 wt% concentrations and bonded in 120 stainless steel molds with processed heat cure acrylic resin blocks. Liner/resin combination samples were divided into two groups. The first half was stored for 2 days in distilled water at 37°C and then subjected to tensile bond strength, while the other half were thermocycled 3000 times before testing. Mean bond strength, expressed in mega pascals (MPa), was determined in the tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min.

STATISTICAL ANALYSIS

 Data were analyzed using SPSS via one-way analysis of variance test, t-test, and Tukey's posthoc, at a 95% confidence level (p < 0.05).

RESULTS

 Addition of SNPs and thermocycling both caused a significant reduction in the tensile bond strength of Mucopren to acrylic resin; however, in the thermocycled group, the bond strength increased with the increase in the concentration of SNPs (p < 0.001).

CONCLUSION

 Addition of SNPs to Mucopren soft silicone liner reduces its tensile bond strength to denture acrylic resin.

In vivo biocompatibility of an interim denture resilient liner containing antifungal drugs

STATEMENT OF PROBLEM

Antifungal agents incorporated into interim denture resilient liners have been suggested as an adjunct treatment for denture stomatitis (DS). However, before applying this protocol to humans, biocompatibility analysis of such drugs in animal models is required.

PURPOSE

The purpose of this animal study was to evaluate the in vivo biocompatibility of an interim resilient liner modified with minimum inhibitory concentrations (MICs) of antifungal drugs for Candida albicans biofilm.

MATERIAL AND METHODS

Sixty Wistar rats were divided into 6 groups (n=5): PC=positive control/no protocol; IOD (intraoral device)=rats using an acrylic resin palatal device (PD); Tru=rats using a PD relined with Trusoft; and Ny (nystatin), Chx (chlorhexidine diacetate), and Ke (ketoconazole) groups=rats using a PD relined with Trusoft + drug MICs. The rats were sacrificed at 7 or 14 days of trial. Histopathological qualitative analysis was performed by comparing photomicrographs of histological sections of the intermolar region. Morphological changes in the epithelium and keratin were quantitatively analyzed by computerized planimetry, and data were analyzed by using 2-way ANOVA and the Tukey HSD test (α=.05).

RESULTS

Quantitative analysis showed that only PD containing Ke significantly decreased the thickness and area of the keratin compared with the other groups (P<.001), which showed no differences between each other (P>.05). These results agreed with those of qualitative analysis.

CONCLUSIONS

Incorporation of MICs of Ny and Chx in Trusoft did not induce histopathological changes in the rat palatal mucosa, suggesting the in vivo biocompatibility of this DS treatment.

Effect of Incorporation of Antifungal Agents on the Ultimate Tensile Strength of Temporary Soft Denture Liners

PURPOSE

To investigate the ultimate tensile strength of temporary soft denture liners modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm (SC5314) determined in previous microbiological research.

MATERIALS AND METHODS

Dumbbell-shaped specimens (n = 7) with a central cross-sectional area of 6 × 3 × 33 mm were produced by Softone and Trusoft, without (control) or with incorporation of drugs in powder form at MICs for C. albicans biofilm (per g of material powder): nystatin (0.032 g), chlorhexidine diacetate (0.064 g), ketoconazole (0.128 g), miconazole (0.256 g), and itraconazole (0.256 g). After plasticization, specimens were immersed in distilled water at 37°C for 24 hours, 7 or 14 days, and then tested in tension in a universal testing machine at 40 mm/min. Data of tensile strength (MPa) and elongation percentage (%) were submitted to 3-way ANOVA and Tukey's test (α = 0.05).

RESULTS

At the end of 14 days, the tensile strength for both materials was significantly lower in the groups modified by miconazole and itraconazole compared to the other groups (p < 0.0001), which showed no significant difference between them (p > 0.05). After 7 and 14 days in water, miconazole and itraconazole added into both materials resulted in significantly lower elongation percentages compared to the other antifungal agents and control (p < 0.0001), which were similar to each other (p > 0.05).

CONCLUSIONS

The addition of the nystatin, chlorhexidine, and ketoconazole at MICs for C. albicans biofilm resulted in no harmful effects on the tensile strength and elongation percentage of the temporary soft denture liner materials up to 14 days.

Surface Properties of Temporary Soft Liners Modified by Minimum Inhibitory Concentrations of Antifungals

Abstract Evaluating the addition of minimum inhibitory concentrations (MICs) of antifungals for Candida albicans biofilm on the hardness and roughness of temporary denture soft liners. Specimens (n=8; 36×7×6 mm) of tissue conditioner (Softone) and resilient liner (Trusoft) were produced either without (control) or with incorporation of drugs at MICs: nystatin (0.032 g/mL), chlorhexidine diacetate (0.064 g/mL), ketoconazole (0.128 g/mL), miconazole (0.256 g/mL) and itraconazole (0.256 g/mL). Specimens were stored in distilled water at 37 °C for 24 h, 7 days and 14 days prior to the hardness/roughness measurements. Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). The addition of the antifungals into both materials demonstrated no evident hardness change or decrease of this property compared with the control, except for miconazole in Softone, which increased the hardness after 14 days (p=0.003). The addition of nystatin into both materials, chlorhexidine in Trusoft and ketoconazole in Softone resulted in no significant changes of roughness compared with the control, after 7 days and 14 days (p>0.05). In these periods, itraconazole increased the roughness of both materials (p<0.001). The addition of all antifungals, except for the miconazole in Softone, resulted in no deleterious effects on the materials’ hardness over the evaluation time. The MICs of nystatin in both temporary soft lining materials, ketoconazole in Softone and chlorhexidine in Trusoft resulted in no deleterious effects for roughness up to 14 days.

Antimicrobial efficacy and mechanical properties of BAC-modified hard and soft denture liners

This study investigated the antimicrobial efficacy and mechanical strength of hard and soft denture liners modified with benzalkonium chloride (BAC). The specimens (1 mm thickness, 8 mm diameter) were prepared by mixing 0.5, 1, 2 and 5 wt% BAC with soft (Sofreliner Medium, Tokuyama) and hard (Rebase II, Tokuyama) denture liners (n = 5/group). BAC was not added to the controls. Candida albicans ATCC 28366 (A ₅₅₀ = 0.5) and Streptococcus mutans Ingbritt suspensions (A ₅₅₀ = 0.35) were pipetted onto the specimens, and incubated for 4 h. The viable cells were collected, and determined by plate-culturing (CFU). The tests were repeated after the specimens were soaked in distilled water for 7 days. The mechanical strengths were evaluated by tear and 4-point flexural strength tests for soft and hard liners, respectively. The data were analyzed with ANOVA and Tukey's HSD tests at p = 0.05. C. albicans viability was lost in all groups of BAC-modified soft liners (p < 0.001), and S. mutans viability was reduced (p < 0.01), except of soaked BAC 0.5 wt% group (p > 0.05). For the hard liner, BAC 5 wt% killed the C. albicans and S. mutans cells both before and after soaked in water (p < 0.001). BAC 2 wt% showed comparable tear strength with the soft liner control (p > 0.05). BAC did not reduce the flexural strength of the hard liner (p > 0.05), except of BAC 5 wt% group (p < 0.01). BAC can be a promising agent reducing the C. albicans and S. mutans viability on the soft and hard denture liner surfaces.

Porosity of temporary denture soft liners containing antifungal agents

Incorporation of antifungals in temporary denture soft liners has been recommended for denture stomatitis treatment; however, it may affect their properties.

Role of antifungal medicaments added to tissue conditioners: A systematic review

PURPOSE

The aim of this review is to investigate the current state of knowledge on the incorporation of antifungal agents into the tissue conditioners for the treatment of denture induced stomatitis.

STUDY SELECTION

Studies reporting the incorporation of antifungal/antimicrobial agents in to tissue conditioners were included in the review. In order to search the studies on the topic "incorporation of antifungal agents in tissue conditioners for the treatment of denture induced stomatitis" ISI web of science, PubMed/MEDLINE, and Google-Scholar databases were searched from 1970 up to and including July 2015 using various keywords such as antifungal agents, tissue conditioners, Candida albicans, denture stomatitis, etc.

RESULTS

Various studies reported the efficacy and effectiveness of adding conventional organic antifungal medicines (nystatin, azole group derivatives and chlorhexidine, antimicrobials/antifungals other than organic (silver zeolite, silver nano-particles, photo-catalysts and metallic oxides) and natural and herbal antimicrobials (tea tree oil, lemongrass essential oil and origanum oil) into various tissue conditioners. The review literature reported that incorporation of antifungal agents into tissue conditioners is effective with minimal or no effects on physical and mechanical properties of tissue conditioners.

CONCLUSIONS

Incorporation of different antifungal medicaments to commercially available tissue conditioners can be recommended for the management of denture induced stomatitis.

Peel bond strength of soft lining materials with antifungal to a denture base acrylic resin

The effect of the addition of nystatin, miconazole, ketoconazole, chlorhexidine, and itraconazole into the soft lining materials Softone and Trusoft on their peel bond strength to a denture base acrylic resin was evaluated. Specimens of soft lining materials (n=7) were made without (control) or with the incorporation of antifungals at their minimum inhibitory concentrations to the biofilm of C. albicans and bonded to the acrylic resin. Peel testing was performed after immersion in distilled water at 37ºC for 24 h, 7 and 14 days. Data (MPa) were analyzed by 3-way ANOVA/Tukey-Kramer test (α=0.05) and the failure modes were classified. The addition of nystatin and ketoconazole did not affect the peel bond strength for up to 14 days. Most failures were predominantly cohesive within soft lining materials. With the exception of itraconazole, incorporating the antifungals into the soft lining materials did not result in values below those recommended for peel bond strength after 7 and 14 days of analysis.

Effect of the addition of antimicrobial agents on Shore A hardness and roughness of soft lining materials

PURPOSE

While the incorporation of antimicrobial agents into soft denture liners has been suggested as a reliable alternative treatment for denture stomatitis, it may affect the liner's properties. The effect of addition of antimicrobial agents for the treatment of denture stomatitis on the surface roughness and Shore A hardness of soft lining materials was evaluated.

MATERIALS AND METHODS

The test groups comprised specimens (36 × 7 × 6 mm(3) ) of soft materials (Softone and Trusoft) without (control) or with incorporation of drugs (nystatin, miconazole, ketoconazole, chlorhexidine diacetate, and itraconazole). Hardness (Shore A) and roughness (Ra) were evaluated after immersion of specimens (n = 10) in distilled water at 37°C for 24 hours, 7 and 14 days. Data were analyzed by 3-way ANOVA/Tukey's test (α = 0.05).

RESULTS

After 14 days, an increase (p < 0.05) was observed in the hardness of soft materials with time for the modified specimens, except for itraconazole. Addition of drugs increased the Softone roughness only for the addition of miconazole and chlorhexidine (p < 0.05), and did not increase the roughness of Trusoft with time. Only chlorhexidine and itraconazole altered the roughness compared to the control for each material (p < 0.05).

CONCLUSIONS

The smallest changes of hardness and roughness with time in the modified groups compared to controls were observed for itraconazole groups for both materials.

Lemongrass-Incorporated Tissue Conditioner Against Candida albicans Culture

BACKGROUND

Tissue conditioner is applied popularly with dental prosthesis during wound healing process but it becomes a reservoir of oral microbiota, especially Candida species after long-term usage. Several antifungal drugs have been mixed with this material to control fungal level. In this study, lemongrass essential oil was added into COE-COMFORT tissue conditioner before being determined for anti-Candida efficacy.

MATERIALS AND METHODS

Lemongrass (Cymbopogon citratus) essential oil was primarily determined for antifungal activity against C. albicans American type culture collection (ATCC) 10231 and MIC (minimum inhibitory concentration) value by agar disk diffusion and broth microdilution methods, respectively. COE-COMFORT tissue conditioner was prepared as recommended by the manufacturer after a fixed volume of the oil at its MIC or higher concentrations were mixed thoroughly in its liquid part. Antifungal efficacy of the tissue conditioner with/without herb was finally analyzed.

RESULTS

Lemongrass essential oil displayed potent antifungal activity against C. albicans ATCC 10231and its MIC value was 0.06% (v/v). Dissimilarly, the tissue conditioner containing the oil at MIC level did not cease the growth of the tested fungus. Both reference and clinical isolates of C. albicans were completely inhibited after exposed to the tissue conditioner containing at least 0.25% (v/v) of the oil (approximately 4-time MIC). The tissue conditioner without herb or with nystatin was employed as negative or positive control, respectively.

CONCLUSION

COE-COMFORT tissue conditioner supplemented with lemongrass essential oil obviously demonstrated another desirable property as in vitro anti-Candida efficacy to minimize the risk of getting Candidal infection.

Effect of antimicrobial agents incorporated into resilient denture relines on the Candida albicans biofilm

OBJECTIVE

The antimicrobial action of five drugs incorporated in temporary denture relines on the fungal biofilm was evaluated.

MATERIALS AND METHODS

A Candida albicans biofilm (SC5314) was formed on specimens (10 × 1 mm) of materials (Trusoft and Softone) modified or not (control) by the drugs (nystatin, miconazole, ketoconazole, itraconazole, and chlorhexidine diacetate). Cell viability was determined spectrophotometrically by the tetrazolium salt reduction assay (XTT) after 24 h, 48 h, and 7 and 14 days of incubation. The minimum inhibitory concentrations (MICs) were those which inhibited 90% or more of fungal growth. Fungal susceptibility was confirmed by confocal laser scanning microscopy analysis.

RESULTS

The MICs of drugs incorporated in the materials were 0.032, 0.256, 0.128, 0.256, and 0.064 g ml(-1) for nystatin, miconazole, ketoconazole, itraconazole, and chlorhexidine, respectively. Images from nystatin, chlorhexidine, and ketoconazole demonstrated no viable cells.

CONCLUSIONS

The antimicrobials incorporated in the resilient materials inhibited fungal growth during 14 days, with lower MICs for nystatin and chlorhexidine.

Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties

The aim of the study was to evaluate the effect of adding acrylamide monomer (AAm) on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly(methyl methacrylate) (PMMA) denture-base resins. Specimens (n=10) were fabricated from a conventional heat-activated QC-20 (Qc-) and a microwave heat-activated Acron MC (Ac-) PMMA resins. Powder/liquid ratio followed the manufacturer's instructions for the control groups (Qc-c and Ac-c) and for the copolymer groups, the resins were prepared with 5% (−5), 10% (−10), 15% (−15) and 20% (−20) acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal–Wallis test (α=0.05) to determine significant differences between the groups. The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis (TGA) with a heating rate of 10 °C⋅min⁻¹ from 35 °C to 600 °C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c (P<0.01). Ac-10 and Ac-15 showed significance when compared to Ac-c (P<0.01). Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c (P<0.01). Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c (P<0.01). According to the ¹H-nuclear magnetic resonance (NMR) results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties.

Antimicrobial properties and cytotoxicity of an antimicrobial monomer for application in prosthodontics

PURPOSE

This study aimed to investigate the antimicrobial properties and cytotoxicity of the monomer methacryloyloxyundecylpyridinium bromide (MUPB), an antiseptic agent capable of copolymerizing with denture base acrylic resins.

MATERIALS AND METHODS

The antimicrobial activity of MUPB was tested against the species Candida albicans, Candida dubliniensis, Candida glabrata, Lactobacillus casei, Staphylococcus aureus, and Streptococcus mutans. The minimum inhibitory and fungicidal/bactericidal concentrations (MIC, MFC/MBC) of MUPB were determined by serial dilutions in comparison with cetylpyridinium chloride (CPC). The cytotoxic effects of MUPB at concentrations ranging from 0.01 to 1 g/L were assessed by MTT test on L929 cells and compared with methyl methacrylate (MMA). The antimicrobial activity of copolymerized MUPB was tested by means of acrylic resin specimens containing three concentrations of the monomer (0, 0.3, 0.6% w/w). Activity was quantified by means of a disc diffusion test and a quantification of adhered planktonic cells. Statistical analysis employed the Mann-Whitney test for MIC and MFC/MBC, and ANOVA for the microbial adherence test (α = 0.05).

RESULTS

MUBP presented lower MIC values when compared with CPC, although differences were significant for C. dubliniensis and S. mutans only (p= 0.046 and 0.043, respectively). MFC/MBC values were similar for all species except C. albicans; in that case, MUPB presented significantly higher values (p = 0.046). MUPB presented higher cytotoxicity than MMA for all tested concentrations (p < 0.001) except at 0.01 g/L. Irrespective of the concentration incorporated and species, there was no inhibition halo around the specimens. The incorporation of MUPB influenced the adhesion of C. albicans only (p = 0.003), with lower CFU counts for the 0.6% group.

CONCLUSIONS

It was concluded that non-polymerized MUPB has an antimicrobial capacity close to that of CPC and high cytotoxicity when compared with MMA. The antimicrobial activity of MUPB after incorporation within a denture base acrylic resin did not depend on its elution, but was shown to be restricted to C. albicans.