Antimicrobial properties of denture adhesives: A scoping review

STATEMENT OF PROBLEM

Denture adhesives have been a focus in prosthodontic research for many years because of the consistently high demand for these products. However, systematic investigations into their antimicrobial properties or effectiveness are limited.

PURPOSE

The purpose of this scoping review was to investigate and evaluate articles on the antimicrobial activity of denture adhesives.

MATERIAL AND METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to describe the result of the scoping review. Four electronic databases were searched for articles in the English language up to October 2023.

RESULTS

A total of 597 published articles were identified, and 40 met the selection criteria for review. Of these, 17 articles reported that denture adhesives with added antimicrobial agents demonstrated antimicrobial effects. Eight articles detailed the antimicrobial effectiveness of denture adhesives that did not contain added antimicrobial agents. Additionally, 11 articles compared the antimicrobial effectiveness of denture adhesives without additional agents. The results varied, with some adhesives showing antimicrobial effects while others with similar compositions did not. Studies indicate that some denture adhesives exhibit antifungal or antibacterial effects; however, whether these effects are associated with the included antimicrobial agents or components or other ingredients is unclear.

CONCLUSIONS

Although extensive studies have attempted to evaluate the antimicrobial efficacy of commercially available denture adhesives and to incorporate additional antimicrobial agents into them, whether the incorporated antimicrobial agents are effective or whether the effects are caused by other ingredients remains unclear.

Development of 3-dimensionally printed denture base material utilizing hybrid polymer: A preliminary investigation

STATEMENT OF PROBLEM

Current 3-dimensionally (3D) printed denture bases have inadequate strength and durability for long-term use, and milled denture bases generate excessive waste. Addressing these limitations is crucial to advancing prosthetic dentistry, ensuring improved patient outcomes and promoting environmental responsibility.

PURPOSE

The purpose of this in vitro study was to incorporate microparticles into a commercially available 3D printed denture base resin and compare its mechanical and biological properties with the conventional polymethyl methacrylate (PMMA) denture base material.

MATERIAL AND METHODS

Microparticles were collected from milled zirconia blanks and were blended with a 3D printing denture base resin (NextDent Denture 3D+). The optimal zirconia microparticle content (2%) for blending and printed was determined by using a liquid-crystal display (LCD) 3D printer. The printed specimens were then postrinsed and postpolymerized based on the manufacturer's instructions. Mechanical and biological characterization were carried out in terms of flexural strength, fracture toughness, and fungal adhesion. One-way ANOVA was carried out to analyze the results statistically.

RESULTS

The incorporation of microparticles in the 3D printed denture demonstrated higher mechanical strength (104.77 ±7.60 MPa) compared with conventional heat-polymerized denture base resin (75.15 ±24.41 MPa) (P<.001), but the mechanical strength deteriorated when compared with the unmodified 3D printing resin (122.17 ±11.58 MPa) (P<.001). However, the modified 3D printed denture showed greater antibacterial activity (1184.00 ±243.25 CFU/mL) than the unmodified resin (1486.50 ±103.94 CFU/mL) (P=.045).

CONCLUSIONS

The incorporation of microparticles into the 3D printed denture base resin demonstrated the potential to enhance the mechanical and biological properties of the denture base when compared with conventional techniques. However, when compared with the unmodified 3D printed denture base resin, the mechanical properties deteriorated while the biological properties improved.

Using Laser Therapy and Topical Ozone as an Effective Intervention to Revolutionize Denture Stomatitis Treatment: A Case Report

In dentistry, denture stomatitis (DS), a frequent inflammatory illness of the oral mucosa mostly related to denture wearing, is a major concern. DS is a common oral mycotic infection for those who wear partial or total dentures. The most often found species of Candida that may be isolated from both healthy and diseased oral tissues is Candida albicans. DS is associated with uneven denture surfaces, inadequate oral hygiene, or ill-fitting dentures. The diagnosis and management of DS in a 72-year-old male patient is presented in this case study. The patient complained about burning in his palate and having difficulty chewing. Upon clinical examination, erythema and inflammation were seen in the palate region. The history and clinical findings were consistent with DS. The patient was told to completely stop using dentures. Interventions were included in the treatment plan, such as diode laser therapy, topical ozonated oil application, and teaching about denture hygiene. The third day's follow-up visit revealed a progressive healing of the lesions and symptom relief. The lesion fully resolved on the sixth day. This case emphasizes the value of all-encompassing management techniques in treating DS successfully. It also highlights the significance of patient education, good oral hygiene, and focused therapy in producing favorable results.

Antifungal effects of eugenol on Candida albicans adherence to denture polymers

Background

The study's objective is to assess the adherence of C. albicans in different types of denture polymers and the effectiveness of eugenol and commercialized denture cleansers in the removal of C. albicans. Three types of denture base polymers (Lucitone® 199 (High-Impact PMMA), Impact® (conventional PMMA) and Eclipse® (UDMA)) and two hard denture reline materials (Kooliner® and Tokuyama® Rebase II Fast) were used in this study.

Methods

Three hundred samples were prepared (6 × 2 mm disc shape) and divided into five groups of denture polymers (n = 60) and further subjected into five treatment groups (Polident®, Steradent, distilled water, eugenol 5-minutes, and eugenol 10-min). Three samples were extracted from each treatment group for baseline data (n = 12). Baseline data were used to calculate the initial number of C. albicans adherence. A 0.5 ml immersion solution from each specimen was cultured on YPD agar and incubated for 48 h at 37 °C. Visible colonies were counted using a colony counter machine (ROCKER Galaxy 230).

Results

The result showed that the denture base polymer significantly affected the initial adherence (p = 0.007). The removal of C. albicans was also considerably affected by the denture base polymers and denture cleansers (p < 0.05). Lucitone®, Tokuyama®, and Kooliner® denture base polymers immersed for 3 min in eugenol showed the best results of removal.

Discussion

This study's overall results showed that all denture polymers used as denture bases had an effect on C. albicans initial adherence and removal from the denture base, and eugenol is comparable to commercialised denture cleansers in reducing the number of attached C. albicans on denture base polymers.

Antifungal Effect of Polymethyl Methacrylate Resin Base with Embedded Au Nanoparticles

Full and partial restorations in dentistry must replicate the characteristics of the patient's natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ΔE between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are smoother and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.

Silver nanoparticles in denture adhesive: An antimicrobial approach against Candida albicans

OBJECTIVE

To evaluate the antimicrobial potential of silver nanoparticles (Ag NPs) synthesized using three different routes (ultraviolet light, Turkevich, and green chemistry method using Glycine max extract) associated with COREGA® denture powder adhesive.

METHODS

Heat-cured acrylic resin specimens were treated with different Ag NPs associated with the adhesive (AD + Ag UV, AD + Ag Turk, and AD + Ag Gm groups). As controls, the specimens were treated with a combination of adhesive and nystatin (AD + Nyst group), only adhesive (AD group), or submerged on the surface of the specimens (PBS group). After the treatments, biofilms of C. albicans developed for 3, 6, and 12 h on the specimen surfaces. The biofilm was quantified using colony-forming units per milliliter, colorimetric assay, and confocal laser scanning microscopy.

RESULTS

Regardless of the period, we observed an inhibition of fungal load and a reduction in metabolic activity and biofilm mass in the resin specimens treated with the combinations AD/Ag NPs, compared to AD and PBS. The antimicrobial action of the AD + Turk and AD + Ag Gm groups was similar than that for the AD + Nyst group in all periods and viability tests, except for the biofilm mass (12 h).

CONCLUSIONS

The COREGA® adhesive with Ag NPs, mainly those synthesized using the Turkevich and Glycine max methods, showed excellent antimicrobial activity against C. albicans biofilms, maintained for up to 12 h.

CLINICAL SIGNIFICANCE

The association of Ag NPs to the adhesive can add preventive or therapeutic effects against denture stomatitis, to this prosthetic material.

Effect of Different Vat Polymerization Techniques on Mechanical and Biological Properties of 3D-Printed Denture Base

Three-dimensional printing is increasingly applied in dentistry to fabricate denture bases. Several 3D-printing technologies and materials are available to fabricate denture bases, but there is data scarcity on the effect of printability, mechanical, and biological properties of the 3D-printed denture base upon fabricating with different vat polymerization techniques. In this study, the NextDent denture base resin was printed with the stereolithography (SLA), digital light processing (DLP), and light-crystal display (LCD) technique and underwent the same post-processing procedure. The mechanical and biological properties of the denture bases were characterized in terms of flexural strength and modulus, fracture toughness, water sorption and solubility, and fungal adhesion. One-way ANOVA and Tukey’s post hoc were used to statistically analyze the data. The results showed that the greatest flexural strength was exhibited by the SLA (150.8±7.93 MPa), followed by the DLP and LCD. Water sorption and solubility of the DLP are significantly higher than other groups (31.51±0.92 μgmm3) and 5.32±0.61 μgmm3, respectively. Subsequently, the most fungal adhesion was found in SLA (221.94±65.80 CFU/mL). This study confirmed that the NextDent denture base resin designed for DLP can be printed with different vat polymerization techniques. All of the tested groups met the ISO requirement aside from the water solubility, and the SLA exhibited the greatest mechanical strength.

An in vitro study on the selection of surfactants for removal of cream denture adhesives from dentures and their application to denture cleaners

PURPOSE

Denture adhesives improve the stability of incompatible dentures; however, complete removal of adhesives after use is difficult. Only a few studies have focused on the removal of denture adhesives. Hence, this study aimed to assess the efficacy of surfactants in removing cream denture adhesives from acrylic resin materials.

METHODS

Solutions of twelve surfactants with various hydrophilic-lipophilic balance (HLB) values were prepared. Two cream denture adhesives, colored for visualization, were spread onto transparent acrylic resin plates. After immersion into surfactant solutions, the effects of the surfactants on residual adhesives were evaluated. We also investigated the effect of denture cleaners (with or without the surfactants) on the removability of adhesives and artificial oily dirt, and their effects on the surface properties of denture materials. The obtained data were analyzed using appropriate statistical methods.

RESULTS

Five surfactants [BT-5, BL-4.2, BT-7, BT-9, and Triton X-100 (TX)] with HLB values in the 10.5-13.5 range effectively removed adhesives. Addition of BT-9 and TX (HLB=13.5) to denture cleaners improved the adhesives' removal. Furthermore, the addition of TX to the cleaners did not interfere with the removal of artificial oily dirt and did not damage the denture materials' surface.

CONCLUSION

Surfactants with HLB values in the 10.5-13.5 range are suitable for removal of cream denture adhesives from acrylic resin materials. In particular, TX (HLB=13.5) efficiently removes adhesives without damaging denture materials or impairing original detergency.

Efficacy of chemical and Photoactivated disinfectants against Candida Albicans and assessment of hardness, roughness, and mass loss of acrylic denture base resin

AIM

The present study aimed to assess the antimicrobial efficacy of hematoporphyrin derivative, sodium hypochlorite (NaOCl), glutaraldehyde (GaH), and a chlorhexidine (CHX) on mass loss (ML), microhardness, and surface roughness (Ra) of acrylic denture base colonized with C. Albicans.

MATERIAL AND METHODS

A total of 40 heat cure acrylic resin dentures were fabricated and inoculated by the American Type Culture Collection (ATCC) of C. Albicans in an in-vitro situation. Specimens were divided into four groups (n=10) based on the method of disinfection. Hematoporphyrin derivatives, 1% NaOCl, 2% GaH, and 4% CHX.The pre and post candida (CFU/ml) counts were recorded before and after immersion. ML, microhardness, and Ra of acrylic denture were also assessed. Statistical analysis was executed for CFU/mL (log10) for exposed C. Albicans by two-way ANOVA and Tukey's multiple tests (p>0.05). For normality of the data, Dunnet's Simultaneous test was performed.

RESULTS

In terms of candida strain analysis, pretreatment to posttreatment comparisons revealed a reduction in mean Candida count in all groups (p<0.05). The highest ML value after post candida disinfection of acrylic denture was observed in 2% GaH (1.587 ± 0.25) treated specimens. The least microhardness value was found in group 1 when treated with hematoporphyrin (0.97 ± 0.22 VHN) which was significantly different from other groups (p<0.05). Group 1 surface treated with hematoporphyrin derivate (1.84 ± 0.22 μm) showed the highest Ra values (p<0.05).

CONCLUSION

Acrylic denture base resin colonized with C. Albicans when treated with a chemical disinfectant of 4% chlorhexidine displayed the highest antimicrobial efficacy with reduced mass loss, less surface roughness, and maximum denture hardness.

Oral Cavity and Candida albicans: Colonisation to the Development of Infection

Candida colonisation of the oral cavity increases in immunocompromised individuals which leads to the development of oral candidiasis. In addition, host factors such as xerostomia, smoking, oral prostheses, dental caries, diabetes and cancer treatment accelerate the disease process. Candida albicans is the primary causative agent of this infection, owing to its ability to form biofilm and hyphae and to produce hydrolytic enzymes and candialysin. Although mucosal immunity is activated, from the time hyphae-associated toxin is formed by the colonising C. albicans cells, an increased number and virulence of this pathogenic organism collectively leads to infection. Prevention of the development of infection can be achieved by addressing the host physiological factors and habits. For maintenance of oral health, conventional oral hygiene products containing antimicrobial compounds, essential oils and phytochemicals can be considered, these products can maintain the low number of Candida in the oral cavity and reduce their virulence. Vulnerable patients should be educated in order to increase compliance.

Denture Stomatitis Revisited: A Summary of Systematic Reviews in the Past Decade and Two Case Reports of Papillary Hyperplasia of Unusual Locations

Objectives

Denture stomatitis is a mucosal condition associated with complete and partial removable dentures. This paper presents a short review of the literature on this topic with more emphasis on the treatment protocols of denture stomatitis as studied in recent systematic reviews.

Methods

A general review of the literature was carried out in the first part of this paper, and then the most recent systematic reviews on the treatment protocols of denture stomatitis were summarized.

Results

Fifteen systematic reviews were collected and classified into six main treatment protocols.

Conclusions

Dentist knowledge of up-to-date treatment options of denture stomatitis will assist comprehensive treatment planning. However, the newer methods of denture disinfection need further studies before recommendation.

Palatal Inflammation and the Presence of Candida in Denture-Wearing Patients

Aim:

Denture stomatitis (DS) is a common inflammatory reaction in denture wearers. The severity of palatal inflammation in DS is believed to be related to Candida colonization. The present study evaluated the presence of Candida at the palatal and the denture surface. The factors associated with DS were also investigated.

Materials and Methods:

Eighty-two denture wearers were evaluated for DS based on Newton’s classification. The samples were collected from palatal mucosa and the denture surface for Candida culture. The predisposing factors associated with DS were also assessed by questionnaire and by oral and dental prosthesis examination.

Results:

Thirty patients showed no signs of DS (36.59%), while 52 patients (63.41%) had DS. Candida was detected in 81.71% of all patients and specifically in 26.83% and 54.88% of non-DS and DS patients, respectively. The proportion of patients with a large amount of Candida at the palatal mucosa in the DS group (40.38%) was higher than in the non-DS group (26.67%) but not significantly different (P > 0.05). The amounts of Candida among the different Newton types also showed no statistically significant differences (P > 0.05). Candida was also detected on the denture surface of the non-DS (34.15%) and DS patients (57.32%). The amounts of Candida on the denture surface between the two groups showed no statistically significant difference (P > 0.05). The predisposing factors related to DS included the absence of occlusal rest and poor denture stability (P < 0.05).

Conclusions:

In this study, no association between the amount of Candida and DS was found. Mycological examination may be useful for the detection of Candida-induced DS and management. However, further study is required to establish a protocol for antifungal drugs prescription in the treatment of Candida-induced DS among the Newton type.

Antifungal activity of polymethyl methacrylate/Si3N4 composites against Candida albicans

Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si₃N₄) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (~8 vol.%) of Si₃N₄ particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si₃N₄ particles at the composite surface, exhibited fungicidal action against Candida albicans. Using a specific nitrative stress sensing dye and highly resolved fluorescence micrographs, we observed in situ congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while these radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. These in situ observations suggest that the surface chemistry of Si₃N₄ mimics the antifungal activity of macrophages, which concurrently produce NO radicals and superoxide anions (O₂•^-) resulting in the formation of candidacidal ONOO^-. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit the uncontrolled growth of Candida albicans and ensuing candidiasis while being synergic with chemoprophylaxis. STATEMENT OF SIGNIFICANCE: In a follow-up of previous studies of gram-positive and gram-negative bacteria, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ could be extended to polymethylmethacrylate (PMMA) containing a minor fraction (~8 vol.%) of Si₃N₄ particles without tangible loss in bulk properties. Hydrolytic products eluted from Si₃N₄ particles at the composite surface exhibited fungicidal action against Candida albicans. Highly resolved fluorescence microscopy revealed congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit uncontrolled growth of Candida albicans and ensuing candidiasis in synergy with chemoprophylaxis.

Retentive efficacy, antimicrobial and cytotoxicity comparisons between different types of commercial and experimental denture adhesives with antifungal action

The effect of the addition of nystatin and an alternative antifungal derived from pyrazoles in different commercial denture adhesives on their retentive efficacy, cytotoxicity and antimicrobial activity against Candida albicans was evaluated. Commercial denture adhesives were prepared with the inclusion of nystatin and 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamide (pyrazole) in three concentrations: 23.78 %w/w, 3.02 %w/w, and 0.31 %w/w (0.015 g, 0.0015 g, and 0.00015 g, respectively). The retentive efficacy was tested observing the influence of the medium, type of commercial denture type and the test condition (dipping). The antifungal action through disk diffusion and direct contact tests at 1, 4, 8 and 12 h and cytotoxic activity was evaluated in mouse fibroblasts (NIH/3T3) by the MTT reduction colorimetric assay. The addition of pyrazole and nystatin in commercial denture adhesives did not affect retentive efficacy rates and enhanced antifungal actions against Candida albicans. Results show a possibility of using denture adhesives as a delivery system for commercial antifungals (Nystatin) or pyrazole, with the second concentration (1,560 µg-3.02 %w/w) as the most efficient.

Removal of denture adhesives from PMMA and Polyamide denture base materials

Denture adhesives need complete removal due to their frequent replacement.

Biocompatibility and Effectiveness of a Novel, Organic Olive Oil-Based Denture Adhesive: A Multicenter Randomized and Placebo-Controlled Clinical Trial

To assess the clinical efficacy of a novel, organic olive oil-based denture adhesive and its effect on Candida albicans growth in maxillary edentulous individuals wearing complete dentures, individuals were selected from two dental schools in Portugal and Spain. Twenty-eight complete dentures were relined, following a standardized protocol. The novel product (test) was compared with a commercialized adhesive (control) and Vaseline (placebo) randomly assigned in a cross-study design. The retention resistance was measured with a gnathometer and a dynamometer. The patients related outcome evaluations with a five-point questionnaire, and the Candida albicans growth in a Sabouraud dextrose agar (SDA) medium was used to evaluate differences between the placebo and experimental product. Twenty-three participants were included. The dynamometer evaluation showed significant differences between not using a denture adhesive and using either (experimental, p = 0.03; control, p = 0.04) and no significant differences between the two adhesives (p > 0.05). In the subjective analysis, the experimental adhesive showed a significantly longer effectiveness (p = 0.001), and the control reported better results in taste (p = 0.03) and in chewing (p = 0.001). The test adhesive showed better (p < 0.001) Candida albicans growth inhibition. The experimental adhesive showed longer effectiveness than the control and the placebo with a better inhibition capacity for the growth of Candida albicans. Patients reported better abilities for speech, chewing, taste, and retirement in the control adhesive.

Inhibition-Disruption of Candida glabrata Biofilms: Symmetrical Selenoesters as Potential Anti-Biofilm Agents

Candida glabrata is one of the most prevalent pathogenic Candida species in dental plaque on tooth surfaces. Candida biofilms exhibit an enhanced resistance against most antifungal agents. Thus, the development of alternative more potent and effective antimicrobials is required to overcome this resistance. In this study, three novel fluorinated derivatives and nine selenoester compounds were screened as novel antifungal and antibiofilm agents against C. krusei, C. parapsilosis, and C. glabrata (N = 81 dental isolates). C. glabrata strains were susceptible only to fluorinated compounds while C. krusei, C. parapsilosis, and C. glabrata were susceptible to the action of the selenoesters. The evaluated symmetrical selenoester compounds presented very good antifungal activity against all the tested C. glabrata dental isolates (1–4 μg/mL of minimum inhibitory concentration-MIC). The most active compound (Se-5) was able to inhibit and disperse C. glabrata biofilms. These results demonstrated that selenoesters may be novel and promising biocide agents against C. glabrata clinical dental isolates.

Influence of the use of complete denture adhesives on microbial adhesion and biofilm formation by single- and mixed-species

Objectives

To verify whether the Ultra Corega Cream and Corega Strip Denture Adhesive adhesives interfere in the microbial adhesion and biofilm formation by Candida albicans and Lactobacillus casei in single- and mixed-species settings, and observe whether synergistic or antagonistic relationships between these species occur.

Methods

Specimens made from heat-polymerized acrylic resin (Lucitone 550) were fabricated (n = 144) with a circular shape and standardized roughness (3.0 μm ±0.3 Ra) and were divided into three groups: Without Adhesive (WA), with Ultra Corega Cream adhesive (CA) and Corega Strips adhesive (SA). These groups were divided into three subgroups each: C. albicans single-species, L. casei single-species and C. albicans with L. casei (mixed-species). Microbial adhesion and biofilm formation assays were performed in duplicate at four distinct experimental times (n = 8 per experimental condition). The amount of each microorganism on the surfaces of the specimens was observed by counting of the Colony Forming Units (CFU) per substrate. Additional specimens were characterized by Scanning Electron Microscopy (SEM), with 18 specimens being used in this analysis (n = 18), 2 per experimental condition (n = 2). Two-way ANOVA and Tukey’s test for multiple comparisons were employed, using α≤0.05.

Results

L. casei (mixed-species) adhered more on the WA substrate than the CA, while C. albicans (single- and mixed-species) adhered more on the SA. C. albicans, both single- and mixed-species adhered more than the L. casei (single- and mixed-species), regardless of the substrate. L. casei (single-species) formed more biofilm on the WA, but in its mixed cultivation, it had no difference of growth among the tested situations. C. albicans (single- and mixed-species) formed more biofilm on the SA than the CA, and the fungus formed more biofilm when compared to L. casei. In general, whenever a species was compared in its single- and mixed-species situation, no statistically significant difference was observed. SEM of biofilm formation assays demonstrated that L. casei single-species WA formed more biofilm than when the adhesives tested were used, and C. albicans (both single- and mixed-species) formed more biofilm on the SA than on the CA.

Conclusions

(1) The two denture adhesives tested increased the adhesion of C. albicans but not of L. casei; (2) biofilm formation by C. albicans (single- and mixed-species) was increased on the SA; (3) Relations of synergism or antagonism was not observed between the two microorganisms studied.

The severity of denture stomatitis as related to risk factors and different Candida spp

OBJECTIVES

1) To select patients with Candida-related denture stomatitis (DS) and to study possible risk factors associated with DS, 2) to evaluate the severity of DS according to Newton's classification, and 3) to investigate the association between the presence of non-albicans Candida spp. (NAC) or mixed Candida spp. and the severity of DS.

STUDY DESIGN

Eighty-two patients with Candida-positive DS have undergone 1) filling in the interview questionnaire, 2) clinical examination, and 3) microbiologic examination.

RESULTS

A total of 113 Candida spp. isolates were obtained from Candida-positive DS patients: C. albicans (as a single species) in 47/82 (57%) patients (study group A [SG_A]) and NAC/mixed Candida spp. in 35/82 (43%) patients (SG_B). Univariate logistic regression analysis showed that older age, longer age of the mandibular denture, and ex-smoker status were associated with SG_A. A multivariate model revealed no significant predictor of DS severity. Patients from SG_A were 3 times as likely to have DS type I, while patients from SG_B were 4.9 times as likely to have DS type III.

CONCLUSIONS

Our results show the association between type III of DS (by Newton's classification) and the presence of NAC or mixed Candida spp. in denture wearers.

Repeated applications of photodynamic therapy on Candida glabrata biofilms formed in acrylic resin polymerized

Previous studies have been suggested that photodynamic therapy (PDT) can be used as an adjuvant treatment for denture stomatitis. In this study, we evaluated the effects of multiple sessions of PDT on Candida glabrata biofilms in specimens of polymerized acrylic resin formed after 5 days. Subsequently, four applications of PDT were performed on biofilms in 24-h intervals (days 6-9). Also, we evaluated two types of PDT, including application of laser and methylene blue or light-emitting diode (LED) and erythrosine. The control groups were treated with physiological solution. The effects of PDT on biofilm were evaluated after the first and fourth application of PDT. The biofilm analysis was performed by counting the colony-forming units. The results showed that between the days 6 and 9, the biofilms not treated by PDT had an increase of 5.53 to 6.05 log (p = 0.0271). Regarding the treatments, after one application of PDT, the biofilms decreased from 5.53 to 0.89 log. When it was done four applications, the microbial reduction ranged from 6.05 log to 0.11 log. We observed that one application of PDT with laser or LED caused a reduction of 3.36 and 4.64 compared to the control groups, respectively (p = 0.1708). When it was done four applications of PDT, the reductions achieved were 1.57 for laser and 5.94 for LED (p = 0.0001). It was concluded that repeated applications of PDT on C. glabrata biofilms showed higher antimicrobial activity compared to single application. PDT mediated by LED and erythrosine was more efficient than the PDT mediated by laser and methylene blue.

Comparative assessment of the effectiveness of different cleaning methods on the growth of Candida albicans over acrylic surface

Context:

This study evaluated the efficacy of denture adhesive, cleanser, chlorhexidine, and brushing against Candida albicans biofilm developed on an acrylic surface and predicted the most effective, simple, and inexpensive way to maintain denture health, thereby preventing denture stomatitis.

Aims:

To find the best possible method for maintaining denture hygiene.

Settings and Design:

This retrospective analysis was conducted in the Guru Nanak Institute of Dental Sciences and Research, Kolkata, and this in vitro study was designed to minimize denture stomatitis among denture wearing population.

Subjects and Methods:

Sixty acrylic discs of equal dimensions after exposure to C. albicans were treated for a duration of 24 h with denture adhesive, cleanser, 0.2% chlorhexidine individually, or in combinations simulating clinical conditions dividing in six groups, ten samples each (n = 10).

Statistical Analysis Used:

After treatment, colony count was evaluated and statistically analyzed by post hoc Tukey's test and Dunnett's test to determine the most effective way of prevention.

Results:

The statistical post hoc analysis (Tukey's test and Dunnett's test) showed high significance (P < 0.0001). The group treated with adhesive showed high fungal growth compared to the control group, whereas chlorhexidine showed high potency to prevent C. albicans, whereas adhesive increased the adhesion of C. albicans to acrylic surface.

Conclusions:

Denture adhesive increases the adherence of C. albicans to denture surface. Other cleaning chemicals such as cleanser and chlorhexidine decrease the adherence. Moreover, among the all denture cleaning protocol, chlorhexidine drastically inhibit the adherence, as well as growth of C. albicans over denture surface.

Effect of Denture-Related Stomatitis Fluconazole Treatment on Oral Candida albicans Susceptibility Profile and Genotypic Variability

Denture-related stomatitis (DRS) is the most common condition affecting removable-denture wearers, and Candida albicans the most frequent pathogenic agent. Systemic antifungal treatment is indicated but recurrences are frequent. The aim of this study was to characterize the oral load, fluconazole susceptibility profile and genotypic variability of oral C. albicans isolates from patients with DRS before (T0), immediately after fluconazole treatment (Tat) and after 6-months follow-up (T6m). Eighteen patients presenting DRS and treated with fluconazole were followed at the Faculty of Dentistry of Oporto University. Seventy C. albicans isolates were obtained and identified using standard cultural and biochemical multi-testing. Fluconazole susceptibility was tested by E-test^®. Microsatellite-primed PCR was performed to assess the genotypic variability of C. albicans isolates. The patients’ mean age was 58.0±3.2 years, and 55.6%/44.4% had total/partial dentures. Before treatment, 22.2%, 44.4% and 33.3% of the patients presented DRS type I, II or III, respectively. Fluconazole treatment healed or improved DRS in 77.8% of the patients, accompanied by an 83.5% reduction in oral C. albicans load. However, after 6-months, oral C. albicans load increased significantly and DRS severity was similar to the one observed before treatment. Moreover, the prevalence of patients presenting fluconazole resistant isolates of C. albicans increased significantly throughout the study: T0-5.6%, Tat-10.0% and T6m-42.9%. A change in the genotypic variability of C. albicans isolates was also verified, being mostly associated to fluconazole susceptibility profile change. In conclusion, fluconazole presents a good short-term DRS treatment efficiency, but may be associated to a long-term emergence of C. albicans fluconazole resistance.