Efficacy of removing Candida albicans from orthodontic acrylic bases: an in vitro study

A Systematic Review of Denture Stomatitis: Predisposing Factors, Clinical Features, Etiology, and Global Candida spp. Distribution

Denture stomatitis (DS) is a very common disease in wearers of removable complete and partial dentures with a worldwide prevalence in the range of 20-67%. Both industrially developed and impoverished nations are affected by the illness. DS is often associated with ill-fitting dentures or a fungal infection with Candida spp. Candida is normally found in the oral cavity microbiota, but it can be harmful to the health of elderly people with underlying diseases. Therefore, the purpose of the present study is to offer the most recent information about the epidemiology, etiology, and global distribution of Candida species associated with DS through a systematic review. Several databases, including Medline, Web of Science, and Scopus, were used to conduct an extensive search of the literature published in the previous 20 years. The selection of studies was performed by two authors. The extracted data were as follows: author, year of publication, country, sample, frequency of DS, method of diagnosing stomatitis, species of Candida, risk factors, and etiology of the disease. The JBI Critical appraisal tools were used to assess the quality of the studies. Eventually, twenty-eight studies were included in the systematic review. Twenty-one studies investigated DS, while seven studies examined Candida colonization in patients using removable dentures. The results show that the main causes of DS include the type of dentures, continuous wearing of dentures, and the formation of a Candida biofilm, which is facilitated by poor dental hygiene. Additionally, previous studies have pinpointed the significance of the salivary flow, saliva composition, and salivary pH. The findings of the current review indicate that it is crucial to monitor denture wearers for the appearance of DS, especially the patients whose immunity has been impaired due to a systemic condition. Finally, frequent follow-ups should include a clinical examination and microbial swabs of the palatal mucosa and the mucosal surface of the denture.

Strategies for Preventing and Treating Oral Mucosal Infections Associated with Removable Dentures: A Scoping Review

Oral infections occur due to contact between biofilm rich in Candida albicans formed on the inner surface of complete dentures and the mucosa. This study investigated historical advances in the prevention and treatment of oral mucosal infection and identified gaps in the literature. Bibliographic research was conducted, looking at PubMed, Embase, Web of Science, and Scopus, where 935 articles were found. After removing duplicates and excluding articles by reading the title and abstract, 131 articles were selected for full reading and 104 articles were included. Another 38 articles were added from the gray literature. This review followed the PRISMA-ScR guidelines. The historical period described ranges from 1969 to 2023, in which, during the 21st century, in vitro and in vivo studies became more common and, from 2010 to 2023, the number of randomized controlled trials increased. Among the various approaches tested are the incorporation of antimicrobial products into prosthetic materials, the improvement of oral and denture hygiene protocols, the development of synthetic and natural products for the chemical control of microorganisms, and intervention with local or systemic antimicrobial agents. Studies report good results with brushing combined with sodium hypochlorite, and new disinfectant solutions and products incorporated into prosthetic materials are promising.

Effects of two novel denture cleansers on multispecies microbial biofilms, stain removal and the denture surface: an in vitro study

BACKGROUND

The continuously increasing demand for removable denture appliances and the importance of adequate denture cleaning have led to the development of various denture cleansing products. The aim of this study was to evaluate the efficacy of two novel denture cleansing agents (GE and TM) and three commonly available cleansers (0.5% sodium hypochlorite; NaClO, 0.12% chlorhexidine gluconate; CHX, and Polident®; POL) on multispecies microbial biofilm formation, stain removal and physical properties of dentures.

METHODS

The antimicrobial activities of denture cleansing agents were determined against major oral opportunistic pathogens including Streptococcus mutans, Staphylococcus aureus, Escherichia coli and Candida albicans, using time-kill assays. Multispecies microbial biofilms grown on acrylic resins for 72 h were generated to determine the antibiofilm effects of cleansing agents by confocal laser scanning microscopy (CLSM). Evaluations of the tea and coffee stain removal properties and the alterations in the physical properties of dentures were also performed. The toxicity of cleanser residues released from denture acrylics to fibroblast cells was investigated using MTT assay.

RESULTS

All denture cleansing agents tested could effectively kill oral bacteria and Candida albicans. Furthermore, after immersion for more than 3 h, the cleansers Polident®, GE and TM could efficiently penetrate and inhibit multispecies denture biofilms with effects similar to 10 min of immersion in 0.5% NaClO. However, immersion in 0.12% CHX for 20 min showed less antibiofilm activity. The NaClO solution had the highest efficacy for removing stains from the artificial teeth. Conversely, the CHX solution enhanced tea and coffee staining, and the teeth immersed in this solution showed clinically unacceptable colour changes (ΔE > 5.5). However, the colour differences of teeth stained and immersed in POL, GE and TM cleansers were in the clinically acceptable range. There was no significant difference among the POL, GE and TM cleansers in terms of stain removal efficacy. The cleansers GE and TM did not alter the surface roughness and colour of the materials, moreover the residues of both cleansers did not exhibit cytotoxicity.

CONCLUSION

Two novel denture cleansing agents containing natural products, GE and TM exhibited effective antimicrobial activity, antibiofilm and stain removal capabilities without toxicity or disturbance of the physical properties of acrylics.

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.

Microbial adherence on vacuum-formed retainers with different surface roughness as constructed from conventional stone models and 3D printed models: a randomized controlled clinical trial

OBJECTIVE

This single center parallel, randomized controlled trial aimed to determine the propensity of microbial adherence on vacuum-formed retainers (VFRs) with different surface roughness imprints.

MATERIALS AND METHODS

Thirty-six patients debonded from fixed appliances at a teaching institution were allocated by block randomization stratified for gender to three groups [VFRs fabricated on conventional, fused deposition modeling (FDM) or stereolithography apparatus (SLA) working models]. Participants wore the VFRs for three months full-time followed by three months part-time. VFRs were collected after each follow-up for Streptococcus and yeast counts. Surface roughness was measured indirectly on the working models using a 3D optical surface texture analyzer. Blinding was not feasible due to appliance appearance. The trial was registered [NCT03844425 ( ClinicalTrials.gov )] and funded by the Universiti Malaya Dental Postgraduate Research Grant (DPRG/14/19).

RESULTS

Thirty participants (eleven conventional, ten FDM, and nine SLA) were analyzed after six dropped out. No harms were reported. Microbial counts between the groups were not significantly different. There were more microbes in the lower VFRs than upper VFRs (total count: p<0.05; effect size, 0.5 during full-time wear and 0.4 during part-time wear). SLA had significantly (p<0.05) smoother surface than FDM (effect size, 0.3) and conventional models (effect size, 0.5). Microbial adherence was not associated with working model surface roughness.

CONCLUSION

Microbial adherence on VFRs was not influenced by degree of surface roughness imprints from working models.

CLINICAL RELEVANCE

3D printed models can be used to make VFRs. Lower VFRs tended to accumulate oral microbes, potentially increasing the oral health risk in the lower arch.

Differences in Supragingival Microbiome in Patients with and without Full-Crown Prostheses

Objectives: To characterize the microflora profile of supragingival biofilm in patients with and without full-crown prostheses. Methods: Plaque samples of full-crown prostheses and teeth in patients with porcelain-fused-to-metal crowns, all-ceramic crowns, and no prostheses were collected (three patients per group), using 16S rRNA high-throughput sequencing technology to conduct DNA sequencing on the samples and using Qiime, R, and PICRUSt2 software to perform bioinformatics analyses and functional analyses on sequencing data. Results: In total, 110,209 valid sequences were obtained in the experiment, corresponding to 11 phyla and 120 genera. The predominant species shared by the three groups were phyla Actinobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Proteobacteria and genera Rothia, Porphyromonas, Prevotella, Streptococcus, Veillonella, Leptotrichia, Neisseria, Citrobacter, and Pseudomonas. The species-difference analysis showed that genus Hameophilus significantly increased after the patient wore the dental prosthesis. Compared with the no-prosthesis samples, the functional analysis showed that cell motility increased in the samples from full-crown prostheses, while replication and repair, and translation decreased. Conclusions: This study reveals the changes in the oral microbial community of patients with full-crown prostheses, which could provide insights regarding the safety of materials for long-term use in the oral cavity.

The Effect of Thymus Vulgaris Essential Oil and Chlorhexidine on Candida Albicans Accumulated on Removable Orthodontic Appliance: A Clinical Trial

Statement of the Problem

Orthodontic removable appliances can facilitate the accumulation of certain microorganisms and microbial plaque on tooth surfaces and appliance components. Since long-term use of chemical agents is not recommended, an alternative option would be medicinal plants for disinfection of the oral cavity.

Purpose

The aim of this study was to assess the efficacy of thymus vulgaris (T. vulgaris) essential oil to decrease the count of candida albicans (C. albicans) accumulated on removal orthodontic appliances.

Materials and Method

In this 2-arm parallel controlled clinical trial, forty-four patients whose removable orthodontic appliances were contaminated with C. albicans were randomly divided into two groups by electronic random sampling. In the first group, T. vulgaris essential oil spray and in the second group, 0.2% chlorhexidine (CHX) spray was applied to the appliances. Thereafter, the C. albicans colony count was measured at baseline (T0) and at 2 (T1) and 5 (T2) days after the intervention. Microbial samples were collected by a sterile swab from 3 spots on the internal surface of orthodontic appliances. The Friedman test was used for within-group comparisons and the Mann Whitney test was employed to compare the efficacy of T. vulgaris essential oil with CHX.

Results

The results of this study revealed that continuous use of 2%T. vulgaris essential oil or 0.2% CHX significantly decreased the colony count of C. albicans on removable orthodontic appliances; Howevere, no significant difference was noted in the efficacy of 2% T. vulgaris essential oil and 0.2% CHX in decreasing the C. albicans colony count.

Conclusion

T. vulgaris essential oil and CHX have favorable antimicrobial activity against C. albicans. Moreover, 2% T. vulgaris essential oil can be considered as an alternative to 0.2% CHX to eliminate fungal contamination of orthodontic appliances.

Evaluation of the time-dependent efficacy of commercial denture or orthodontic appliance cleansers: An in vitro study

The aim of this study was to evaluate the antimicrobial, stain and protein removal efficacy of denture or orthodontic appliance cleansers using in vitro test methods. Experimental cleansers were applied for experimental time in each evaluation method. To evaluate the microorganism removal efficacy, C. albicans and S. mutans removal rate was calculated from the specimen surface. Stain and protein removal rate was calculated using the spectrophotometer. Experimental cleansers significantly affected the microorganism removal rate for both C. albicans and S. mutans, as well as the stain and protein removal rates, at each experimental time (p<0.05). As the application time increased, the stain and protein removal rates of all experimental cleansers significantly increased (p<0.05). The present study provided in vitro evaluation methods to assess the efficacy of denture or orthodontic appliance cleansers. Also, manufacturers and researchers can predict clinical outcomes and ensure proper hygiene management of dentures or orthodontic appliances.

Effects of chlorhexidine mouthwash on the oral microbiome

INTRODUCTION/OBJECTIVES

Chlorhexidine (CHX) is a commonly used mouthwash with potent anti-microbial effects useful for the management of oral disease. However, we are moving away from the view of simply 'killing' bacteria, towards managing oral microbial ecosystems (oral microbiome), as an integrated system, to promote oral and systemic health. Here, we aimed to review the effects of CHX mouthwash on the balance of microbial communities in the mouth in vivo in oral health and disease.

SOURCES AND STUDY SECTION

The hierarchy of evidence was applied, with systematic reviews and randomised controlled trials consulted where available and case controlled studies being described thereafter. Search terms for each subject category were entered into MEDLINE, PubMed, Google Scholar and the Cochrane database. Focussing on metagenomics studies provides unique overview of the oral microbiome as an integrated system.

DATA

Evidence was limited, but several next generation sequencing case-controlled studies suggested that in an integrated system, CHX may cause a shift towards lower bacterial diversity and abundance, in particular nitrate-reducing bacteria in vivo. CHX also appeared to alter salivary pH, lactate, nitrate and nitrite concentrations in saliva. Evidence regarding the effects of CHX on the oral microbiome during oral disease is still emerging.

CONCLUSIONS

CHX alters the composition the oral microbiome. However, as CHX use remains widespread in dentistry to manage oral disease, urgent research using metagenomics studies of microbial communities in vivo are still needed to determine CHX mouthwash is 'good', 'bad' or otherwise for bacteria, in the context of oral and systemic health.

Oral Colonization and Virulence Factors of Candida spp. in Babies With Cleft Palate

OBJECTIVE

To examine oral colonization and virulence factors of Candida spp. in patients aged from 0 to 18 months with cleft palate (CP).

MATERIALS AND METHODS

Sixty babies were allocated into 3 groups: CP, CP with orthodontic plate (CPwP), and control group (Ctrl) without CP. Information on feeding habits, hygiene, and history of candidosis was collected. The presence of Candida spp. was investigated in samples of saliva. Fungal hydrophobicity, protease, esterase, phospholipase, and hemolysin were evaluated in a semiquantitative manner.

RESULTS

Positive oral isolations of Candida spp. were detected in CP (89.5%), CPwP (100%), and Ctrl (44%) groups. Candidosis was more reported in the cleft groups than in the Ctrl group (P ≤ .023). There was a higher prevalence of Candida albicans, followed by Candida krusei, Candida tropicalis, and Candida parapsilosis in all groups. There was no uniformity of expression of virulence factors, either among different species or among different groups.

CONCLUSION

Candida spp. colonization occurred in all groups, being superior in CPwP group. Candidosis episodes were more reported in patients from CPwP than in other groups, although candidosis was also registered in other groups. Candida albicans was the predominant species and virulence factors did not exhibit any pattern for species or groups of patients.

Synthesis, Antifungal Activity, and Cytotoxicity of AgBr-NP@CTMAB Hybrid and Its Application in PMMA

Objective

To synthesize and determine the antifungal activity of AgBr-nanoparticles (NP) @CTMAB (cetyltrimethyl-ammonium bromide) against Candida albicans (C. albicans) for use in the field of denture cleaning.

Methods

The morphology and structure of AgBr-NP@CTMAB were characterized by IR, UV-Vis, XRD and SEM. The antifungal potential of AgBr-NP@CTMAB against C. albicans was determined by colony formation assay and growth curve analysis. PMMA containing AgBr-NP@CTMAB was prepared, and the long-term antifungal efficacy was analyzed. The effect against C. albicans biofilm was analyzed by SEM and OD600 , and the color changes of the specimens were observed by stereomicroscopy after 1 week of incubation. Cytotoxicity to human oral gingival fibroblasts and oral mucosal epithelial cells was detected by Cell Counting Kit-8 (CCK-8) in vitro.

Results

The compound showed a good crystalline phase, the presence of AgBr nanoparticles and the hybridization of CTMAB+ with AgBr-NPs. AgBr-NP@CTMAB showed significant antifungal activity against C. albicans at concentrations of 10 μg/mL and 20 μg/mL. PMMA specimens containing AgBr-NP@CTMAB showed no long-term antifungal effect against C. albicans biofilm. The clearance rate of C. albicans attached to PMMA was 44.73% after soaking in 10 µg/mL AgBr-NP@CTMAB solution for 30 min and 91.35% for 8 h. There was no significant residual cytotoxicity or visual color change after soaking.

Significance

AgBr-NP@CTMAB showed promising potential treatment for denture cleaners.

Highly efficient antibiofilm and antifungal activity of green propolis against Candida species in dentistry materials

This study evaluated the effect of green propolis extract on the adhesion and biofilm formation of Candida species in dentistry materials. Phytochemical analysis of green propolis extract was performed by high-performance liquid chromatography. Adhesion was quantified by counting the number of yeast cells adherent to dental material fragments in a Neubauer chamber. Biofilm formation was determined by counting colony-forming units recovered from dental material fragments. The intensity of biofilm adhesion was classified as negative, weak, moderate, strong, or very strong. Fifteen compounds, mainly flavonoids, were identified in green propolis extract. All strains adhered to and formed biofilms on the surfaces of the orthodontic materials studied. On steel and resin, yeast cell adhesion intensities were weak at all incubation times, except for those of Candida parapsilosis and C. tropicalis, which were moderate at 12 h. At 24 and 48 h, C. albicans formed biofilms on steel with moderate adhesion affinities; at 24 and 48 h, C. parapsilosis formed biofilms with very strong affinities. C. tropicalis formed biofilms with strong and very strong affinities at 24 and 48 h, respectively. On resin, all species displayed strong affinity for biofilm formation at 24 and 48 h, except for C. tropicalis, which displayed very strong affinity at only 48 h. Green propolis extract displayed antifungal activity and inhibited both adhesion and biofilm formation at 2.5 μg/mL. This study reinforces the idea that green propolis has antifungal activity and interferes with the virulence of Candida species.

Current uses of chlorhexidine for management of oral disease: a narrative review

Objectives

Chlorhexidine (CHX) is a commonly used antiseptic mouthwash, used by dental practitioners and the public, due to its antimicrobial effects. The aim of this article was to provide a narrative review of current antimicrobial uses of CHX relevant to dentistry in the context of oral diseases, highlighting need for further studies to support its safe and appropriate use.

Study selection, data and sources

Randomised controlled trials, systematic reviews and national (UK and US) guidelines were consulted where available, with search terms for each subject category entered into MEDLINE, PubMed, Google Scholar and the Cochrane database.

Results

Some evidence existed to support adjunctive short-term use of CHX to manage dental plaque, and reduce clinical symptoms of gingivitis, dry socket, as well as reduce aerosolisation of bacteria. However, use must be weighed alongside the less desirable effects of CHX, including extrinsic staining of teeth, antimicrobial resistance to antiseptic agents and the rare, but fatal, allergic reactions to CHX. Conversely, evidence for the effectiveness of chlorhexidine to manage or prevent periodontitis, dental caries, necrotising periodontal diseases, peri-implantitis, and infections associated with extraction and aerosolised viruses remains less certain.

Conclusions

The use of CHX in dentistry and oral healthcare continues to be widespread and thus it is important that dental practitioners understand that, based on its differential mechanisms of action on different microbes, appropriate clinical and dental use of CHX should be oral disease specific. However, further scientific and clinical research is required before full recommendations can be made.