In vitro cariogenic potential of Candida albicans

Oral Candida-biome and Early Childhood Caries: A Systematic Review and Meta-Analysis

OBJECTIVE

Candida is a common fungal pathogen in the oral cavity, with Candida albicans being the most prevalent species. Some studies report a correlation between Candida prevalence and dental caries experience in preschoolers, while others report no such association. This systematic review and meta-analysis aimed to evaluate the association of Candida-biome with Early Childhood Caries (ECC) in preschool children.

METHODS

Seven databases were searched for studies evaluating the correlation between Candida and ECC in healthy preschool children under 71 months of age. Dual independent screening, data extraction, bias risk assessment, meta-analysis, and quality evaluation of evidence were conducted.

RESULTS

The review included 20 studies with 12 reporting a positive association between Candida prevalence and ECC. The prevalence of Candida albicans in ECC ranged from 60%-84% across sample sites. Certain specific species, including C. dubliniensis and atypical non-albicans Candida (NAC), were also associated with caries severity in preschoolers. The pooled odds ratio (OR) estimate was 7.98 (95%CI; 3.84-16.58) for Candida-biome in plaque samples (I² = 84%), and 9.42 (95%CI: 4.15- 21.40) for Candida-biome in saliva sample (I² = 50%). These results suggest that children with Candida-biome in plaque and saliva have higher odds of having ECC than caries-free children.

CONCLUSIONS

Children with Candida-biome in plaque and saliva samples have a higher risk of Early Childhood Caries, predominantly associated with Candida albicans. Standardised methodologies for evaluating and comparing data on Candida species and ECC are recommended for future studies.

'Green' silver nanoparticles combined with tyrosol as potential oral antimicrobial therapy

OBJECTIVES

This study aimed to evaluate silver nanoparticles (AgNPs) obtained by a 'green' route associated or not to tyrosol (TYR) against Streptococcus mutans and Candida albicans in planktonic and biofilms states.

METHODS

AgNPs were obtained by a 'green' route using pomegranate extract. The minimum inhibitory concentration (MIC) against S. mutans and C. albicans was determined for AgNPs and TYR combined and alone, and fractional inhibitory concentration index (FICI) was calculated. Single biofilms of C. albicans and S. mutans were cultivated for 24 h and then treated with drugs alone or in combination for 24 h.

RESULTS

AgNPs and TYR were effective against C. albicans and S. mutans considering planktonic cells alone and combined. The MIC values obtained for C. albicans was 312.5 µg/mL (AgNPs) and 50 mM (TYR) and for S. mutans was 78.1 µg/mL (AgNPs) and 90 mM (TYR). The combination of these antimicrobial agents was also effective against both microorganisms: 2.44 µg/mL/0.08 mM (AgNPs/TYR) for C. albicans and 39.05 µg/mL /1.25 mM (AgNPs/TYR) for S. mutans. However, synergism was observed only for C. albicans (FICI 0.008). When biofilm was evaluated, a reduction of 4.62 log10 was observed for S. mutans biofilm cells treated with AgNPs (p < 0.05, Tukey test). However, the addition of TYR to AgNPs did not improve their action against biofilm cells (p > 0.05). AgNPs combined with TYR demonstrated a synergistic effect against C. albicans biofilms.

CONCLUSIONS

These findings suggest the potential use of AgNPs with or without TYR against C. albicans and S. mutans, important oral pathogens.

CLINICAL SIGNIFICANCE

AgNPs obtained by a 'green' route combined or not with TYR can be an alternative to develop several types of oral antimicrobial therapies and biomaterials.

Multilocus sequence typing of Candida albicans oral isolates reveals high genetic relatedness of mother-child dyads in early life

Candida albicans is a pathogenic fungus recently recognized for its role in severe early childhood caries development (S-ECC). C. albicans oral colonization begins at birth, but the extent of the mother's involvement in yeast transmission to their children is unclear, therefore, this study used a prospective mother-infant cohort to investigate the maternal contribution of C. albicans oral colonization in early life. Oral samples were collected from 160 mother-child dyads during pregnancy and from birth to two years of life. We used whole-genome sequencing to obtain the genetic information of C. albicans isolates and examined the genetic relatedness of C. albicans between mothers and their children using Multilocus Sequence Typing. Multivariate statistical methods were used to identify factors associated with C. albicans' acquisition (horizontal and vertical transmissions). Overall, 227 C. albicans oral isolates were obtained from 93 (58.1%) of mother-child pairs. eBURST analysis revealed 16 clonal complexes, and UPGMA analysis identified 6 clades, with clade 1 being the most populated 124 isolates (54.6%). Significantly, 94% of mothers and children with oral C. albicans had highly genetically related strains, highlighting a strong maternal influence on children's C. albicans acquisition. Although factors such as race, ethnicity, delivery method, and feeding behaviors did not show a significant association with C. albicans vertical transmission, the mother's oral hygiene status reflected by plaque index (PI) emerged as a significant factor; Mothers with higher dental plaque accumulation (PI >=2) had a significantly increased risk of vertically transmitting C. albicans to their infants [odds ratio (95% confidence interval) of 8.02 (1.21, 53.24), p=0.03]. Furthermore, Black infants and those who attended daycare had an elevated risk of acquiring C. albicans through horizontal transmission (p <0.01). These findings highlight the substantial role of maternal transmission in the oral acquisition of C. albicans during early life. Incorporating screening for maternal fungal oral carriage and implementing oral health education programs during the perinatal stage may prove valuable in preventing fungal transmission in early infancy.

Exploring the biomedical potential of a novel modified glass ionomer cement against the pandrug-resistant oral pathogen Candida albicans SYN-01

Dental caries is an infectious disease that is a major concern for dentists. Streptococci and Lactobacilli were long thought to be the primary etiology responsible for caries. Candida albicans with acidogenic and aciduric characteristics has recently been implicated in the onset and progression of cariogenic lesions. Moreover, due to the increased resistance to common antimicrobials, the discovery of innovative candidates is in high demand. Therefore, our study might be the first report that explores the efficacy of glass ionomer cement (GIC) incorporated with a newly modified carboxylated chitosan derivative (CS-MC) against multidrug-resistant (MDR) and/or pandrug resistant (PDR) C. albicans isolated from the oral cavity. In this work, four CS-MC-GIC groups with different concentrations were formulated. Group four (CS-MC-GIC-4) gave a significant performance as an anticandidal agent against selected PDR Candida strain, with an obvious decrease in its cell viability and high antibiofilm activity. It also, enhanced all the mechanical properties and supports cell viability of Vero cells as a nontoxic compound. Moreover, CS-MC-GIC-4 inhibited neuraminidases completely, which might provide a novel mechanism to prevent dental/oral infections. Thus, findings in this study open up new prospect of the utilization of CS-MC-GIC as a novel dental filling material against oral drug-resistant Candida.

Biomineral-binding liposomes with dual antibacterial effects for preventing and treating dental caries

Dental caries is a chronic oral disease that results from the demineralization of dental hard tissues caused by the long-term interaction of various pathogenic factors in the human oral cavity. Although magnolol (Mag) and fluconazole (FLC) have shown promising antibacterial activity against Candida albicans (C. albicans) and Streptococcus mutans (S. mutans), their clinical application is limited due to hydrophobicity. In this study, we constructed biomineral-binding liposomes co-loaded with Mag and FLC (PPi-Mag/FLC-LPs) to overcome the hydrophobicity and achieve a dual antibacterial activity in the acidic microenvironment of caries. PPi-Mag/FLC-LPs were characterized by laser particle size analysis, transmission electron microscopy, and high-performance liquid chromatography (HPLC). The ability of PPi-Mag/FLC-LPs to bind hydroxyapatite was assessed in vitro using fluorescence microscopy and HPLC, while the antibacterial activity was examined by measuring drug effects on the acidogenicity, acid resistance, biofilm formation and survival of C. albicans and S. mutans. The pharmacodynamics of PPi-Mag/FLC-LPs was also evaluated in vivo in a rat model of dental caries. Mag and FLC were released rapidly from PPi-Mag/FLC-LPs in a pH-sensitive manner, and they bound effectively to hydroxyapatite, leading to a better antibacterial effect on C. albicans and S. mutans compared to free drugs or liposomes loaded with a single drug. PPi-Mag/FLC-LPs improved the medicinal properties of Mag and FLC and provided a rapid, pH-sensitive release of both drugs in vitro. PPi-Mag/FLC-LPs displayed good antibacterial activity in vivo, showing promise as a dual-drug delivery system for the prevention and treatment of caries.

Roles of Streptococcus mutans-Candida albicans interaction in early childhood caries: a literature review

As one of the most common oral diseases in kids, early childhood caries affects the health of children throughout the world. Clinical investigations show the copresence of Candida albicans and Streptococcus mutans in ECC lesions, and mechanistic studies reveal co-existence of C. albicans and S. mutans affects both of their cariogenicity. Clearly a comprehensive understanding of the interkingdom interaction between these two microorganisms has important implications for ECC treatment and prevention. To this end, this review summarizes advances in our understanding of the virulence of both C. albicans and S. mutans. More importantly, the synergistic and antagonistic interactions between these two microbes are discussed.

Effects of Nystatin oral rinse on oral Candida species and Streptococcus mutans among healthy adults

OBJECTIVES

To examine the effect of Nystatin oral rinse on oral Candida species and Streptococcus mutans carriage.

MATERIALS AND METHODS

Twenty healthy adults with oral candidiasis participated in the single-arm clinical trial and received Nystatin oral rinse for 7 days, 4 applications/day, and 600,000 International Units/application. Demographic-socioeconomic-oral-medical conditions were obtained. Salivary and plaque Candida species and Streptococcus mutans were assessed at baseline and 1-week and 3-month follow-ups. Twenty-four salivary cytokines were assessed. Candida albicans isolates underwent Nystatin susceptibility test.

RESULTS

Half of participants (10/20) were free of salivary C. albicans after using Nystatin rinse. Salivary S. mutans was significantly reduced at 3-month follow-up (p < 0.05). Periodontal status reflected by bleeding-on-probing was significantly improved at 1-week and 3-month follow-ups (p < 0.05). Plaque accumulation was significantly reduced at 1-week follow-up (p < 0.05). Interestingly, the responses to Nystatin oral rinse were not associated with race, gender, age, oral hygiene practice, adherence to Nystatin rinse, or sweet consumption (p > 0.05). No C. albicans isolates were resistant to Nystatin. Furthermore, salivary cytokine eotaxin and fractalkine were significantly reduced at 3-month follow-up among participants who responded to Nystatin rinse (p < 0.05).

CONCLUSIONS

The study results indicate that oral antifungal treatment had an effect on S. mutans salivary carriage. Future clinical trials are warranted to comprehensively assess the impact of antifungal treatment on the oral flora other than S. mutans and Candida.

CLINICAL RELEVANCE

Due to the potential cariogenic role of oral Candida species, antifungal approaches shed new light on the prevention and management of dental caries from a fungal perspective.

Gene expression analysis of toll like receptor 2 and 4, Dectin-1, Osteopontin and inflammatory cytokines in human dental pulp ex-vivo

BACKGROUND

Toll like receptors (TLR) 2 and 4 present on innate immune cells of the dental pulp detect cariogenic bacteria. Along with bacteria, C. albicans may also be present in dental caries. The presence of C. albicans can be detected by Dectin-1 a C type Lectin receptor. Expression of Dectin-1 in human pulpits has not been reported. Similarly, cytokines are released as a consequence of dental pulp inflammation caused by cariogenic bacteria. The T helper (Th) 1 inflammatory response leads to exacerbation of inflammation and its relationship with Osteopontin (OPN) is not known in pulp inflammation.

OBJECTIVE

The aim of this study was to observe the expression of Dectin-1, TLR-2, OPN and pro-inflammatory cytokines in irreversibly inflamed human dental pulp and to observe relationship between Dectin-1/TLR-2 and OPN/Pro-inflammatory cytokines in the presence of appropriate controls.

METHODS

A total of 28 subjects diagnosed with irreversible pulpitis were included in this ex-vivo study. Fifteen samples were subjected to standard hematoxylin and Eosin (H&E) and immunohistochemistry staining. Whereas, gene expression analysis was performed on 13 samples to observe mRNA expression of pro-inflammatory cytokines; tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1 beta (ß), IL-6 Dectin-1, OPN, TLR-2 and TLR-4. SPSS version 21 was used for statistical analysis. One way analysis of variance (ANOVA), Pearson correlation and Chi-square test were used at p ≤ 0.05.

RESULTS

Gene expressions of Dectin-1, TLR-2 and TLR-4 were observed in all samples. Dectin-1 and TLR-2 expressions were significantly correlated (r = 0.5587, p = 0.0002). Similarly, OPN and TNF-α expression showed a significant correlation (r = 0.5860, p = 0001). The agreement between histologic and clinical diagnosis was 69.2% in the cases of irreversible pulpitis.

CONCLUSION

Dectin-1 was expressed by inflamed human dental pulp. Dectin-1 and TLR-2 expression pattern was suggestive of a collaborative receptor response in inflamed pulp environment. OPN and TNF-α expressions showed a positive correlation indicating a possible relationship.

Candida albicans and Early Childhood Caries

Early childhood caries (ECC) is a highly prevalent and costly chronic oral infectious disease in preschool children. Candida albicans has been frequently detected in children and has demonstrated cariogenic traits. However, since ECC is a multifactorial infectious disease with many predisposing non-microbial factors, it remains to be elucidated whether the presence and accumulation of C. albicans in ECC is merely a consequence of the adaptation of C. albicans to a cariogenic oral environment, or it plays an active role in the initiation and progression of dental caries. This review aims to summarize the current knowledge on C. albicans and the risk of ECC, with a focus on its synergistic relationship with the cariogenic pathogen Streptococcus mutans. We also highlight recent advances in the development of approaches to disrupt C. albicans-S. mutans cross-kingdom biofilms in ECC prevention and treatment. Longitudinal clinical studies, including interventional clinical trials targeting C. albicans, are necessary to ascertain if C. albicans indeed contributes in a significant manner to the initiation and progression of ECC. In addition, further work is needed to understand the influence of other bacteria and fungi of oral microbiota on C. albicans-S. mutans interactions in ECC.

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.

Fungal species in endodontic infections: A systematic review and meta-analysis

Fungal infections are common on oral mucosae, but their role in other oral sites is ill defined. Over the last few decades, numerous studies have reported the presence of fungi, particularly Candida species in endodontic infections, albeit in relatively small numbers in comparison to its predominant anaerobic bacteriome. Here, we review the fungal biome of primary and secondary endodontic infections, with particular reference to the prevalence and behavior of Candida species. Meta-analysis of the available data from a total of 39 studies fitting the inclusion criteria, indicate the overall weighted mean prevalence (WMP) of fungal species in endodontic infections to be 9.11% (from a cumulative total of 2003 samples), with 9.0% in primary (n = 1341), and 9.3% in secondary infections (n = 662). Nevertheless, WMP for fungi in primary and secondary infections which were 6.3% and 7.5% for culture-based studies, increased to 12.5% and 16.0% in molecular studies, respectively. The most prevalent fungal species was Candida spp. The high heterogeneity in the reported fungal prevalence suggests the need for standardized sampling, and speciation methods. The advent of the new molecular biological analytical platforms, such as the next generation sequencing (NGS), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF), that enables identification and quantitation of a broad spectrum of hitherto unknown organisms in endodontic infections should radically alter our understanding of the endodontic mycobiome in the future. Candida spp. appear to be co-pathogens with bacteria in approximately one in ten patients with endodontic infections. Hence, clinicians should comprehend the importance and the role of fungi in endodontic infections and be cognizant of the need to eradicate both bacteria and fungi for successful therapy.

Curcumin-loaded Pluronic® F-127 Micelles as a Drug Delivery System for Curcumin-mediated Photodynamic Therapy for Oral Application

Antimicrobial photodynamic therapy (aPDT) is promising for oral decontamination. Curcumin has been used as photosensitizer; however, the hydrophobic properties can negatively affect aPDT. This study evaluated the aPDT efficacy using Cur-loaded Pluronic^® F-127 micelles against Streptococcus mutans and Candida albicans biofilms. Micelles characterization was performed by zeta potential, dynamic light scattering, transmission electron microscopy, absorption and fluorescence spectroscopy. Cur concentrations, cell viability by CFU mL^-1 and confocal microscopy were determined. Data were analyzed by parametric and nonparametric tests under 5%. Cur-loaded Pluronic^® F-127 exhibited spherical shape, suitable particle size (≤100 nm), adequate polydispersity index, best stability, lower photodegradation and autoaggregation compared to unloaded-Cur. Both microorganisms were sensitive to Cur-loaded Pluronic^® F-127 micelles aPDT, with minimum inhibitory concentration (MIC) of 270 μm and 2.1093 μm for S. mutans and C. albicans suspended culture, respectively. Cur-loaded Pluronic^® F-127 aPDT exhibited antibacterial/antifungal effect against the biofilms (~3 log₁₀ reduction; P ≤ 0.05); however, similar to unloaded (P ≥ 0.05). Confocal images confirmed these results. Cur-loaded Pluronic^® F-127 micelles exhibited good photo-chemical properties and may be a viable alternative to deliver Cur and to improve aPDT effect during the treatment of dental caries. Moreover, Pluronic^® micelles can enhance the solubility, stability, permeability and control the release of Cur.

Anticaries activity of GERM CLEAN in Streptococcus mutans and Candida albicans dual-species biofilm

OBJECTIVE

To evaluate the antimicrobial effects of a peptide containing novel oral spray GERM CLEAN on dual-species biofilm formed by Streptococcus mutans and Candida albicans and to investigate whether GERM CLEAN inhibits the demineralization procedure of bovine enamel in vitro.

METHODS

The antimicrobial effects of GERM CLEAN on dual-species biofilm were analyzed by initial adherence rate calculation, water-insoluble exopolysaccharides quantification, total biomass quantification, and colony-forming units (CFUs) counting. Scanning electron microscopy and confocal laser scanning microscopy were applied to evaluate the impacts of GERM CLEAN on the biofilm structure. Further, the effects of GERM CLEAN on acidogenicity of dual-species were appraised via glycolytic pH drop analysis and hydroxyapatite dissolution measurement. The percentage of Surface Microhardness Reduction (%SMHR) evaluation, Atomic Force Micrograph (AFM) examination, and Transverse Microradiography (TMR) analysis after pH cycling were used to determine whether GERM CLEAN inhibited the demineralization of bovine enamel.

RESULTS

GERM CLEAN decreased the adherence rate, water-insoluble EPS production, biofilm formation, and acidogenicity of the dual-species. Moreover, GERM CLEAN significantly inhibited the demineralization status of bovine enamels.

CONCLUSION

This peptide containing novel oral spray GERM CLEAN has antimicrobial potential toward the dual-species. GERM CLEAN can also impede the demineralization procedure of enamel.

Isolation and Identification of Potentially Pathogenic Microorganisms Associated with Dental Caries in Human Teeth Biofilms

Dental caries is attributed to the predominance of cariogenic microorganisms. Cariogenic microorganisms are pathological factors leading to acidification of the oral microenvironment, which is related to the initiation and progression of caries. The accepted cariogenic microorganism is Streptococcus mutans (S. mutans). However, studies have found that caries could occur in the absence of S. mutans. This study aimed to assess the presence of potentially cariogenic microorganisms in human teeth biofilm. The microorganisms were isolated from human mouth and freshly extracted human maxillary incisors extracted for reasons of caries. The isolates were sorted based on their acidogenic and aciduric properties, and the S. mutans was used as the reference strain. Four potentially cariogenic strains were selected. The selected strains were identified as Streptococcus salivarius (S. salivarius), Streptococcus anginosus (S. anginosus), Leuconostoc mesenteroides (L. mesenteroides), and Lactobacillus sakei (L. sakei) through morphological analysis followed by 16S rRNA gene sequence analysis. The cariogenicity of isolates was analyzed. We show, for the first time, an association between L. sakei (present in fermented food) and dental caries. The data provide useful information on the role of lactic acid bacteria from fermented foods and oral commensal streptococci in dental caries.

An In Vitro Study on the Antimicrobial Properties of Essential Oil Modified Resin Composite against Oral Pathogens

Modifying the composition of dental restorative materials with antimicrobial agents might induce their antibacterial potential against cariogenic bacteria, e.g., S. mutans and L. acidophilus, as well as antifungal effect on C. albicans that are major oral pathogens. Essential oils (EOs) are widely known for antimicrobial activity and are successfully used in dental industry. The study aimed at evaluating antibacterial and antifungal activity of EOs and composite resin material (CR) modified with EO against oral pathogens. Ten EOs (i.e., anise, cinnamon, citronella, clove, geranium, lavender, limette, mint, rosemary thyme) were tested using agar diffusion method. Cinnamon and thyme EOs showed significantly highest antibacterial activity against S. mutans and L. acidophilus among all tested EOs. Anise and limette EOs showed no antibacterial activity against S. mutans. All tested EOs exhibited antifungal activity against C. albicans, whereas cinnamon EO showed significantly highest and limette EO significantly lowest activity. Next, 1, 2 or 5 µL of cinnamon EO was introduced into 2 g of CR and microbiologically tested. The modified CR showed higher antimicrobial activity in comparison to unmodified one. CR containing 2 µL of EO showed the best antimicrobial properties against S. mutans and C. albicans, while CR modified with 1 µL of EO showed the best antimicrobial properties against L. acidophilus.

Evaluation of antifungal activity of six children's toothpaste on Candida albicans isolated from early childhood caries patients

BACKGROUND

Early childhood caries (ECC) is an aggressive, destructive form of dental caries that affects the children younger than 6 years of age. Candida is known to increase the adherence of Streptococcus mutans to the oral biofilm and produce acids that cause tooth demineralization.

AIM OF THE STUDY

To evaluate the efficacy of six commercially available children's toothpaste on clinical isolates of Candida albicans obtained from ECC patients.

MATERIALS AND METHODS

The study population comprised 60 children aged 3-6 years having ECC. Samples were divided into six groups comprising ten children in each group. Samples were collected using sterile cotton swabs, inoculated on Sabouraud dextrose agar, and incubated at 37°C for 24 h. Species identification was done by germ tube test and growth on corn meal agar. After the confirmed growth of C. albicans, the six commercially available children's toothpaste namely Organic Children's Coconut Oil Toothpaste^®, Aloe Dent Children's Toothpaste^®, Patanjali Dant Kanti Junior Toothpaste^®, Colgate Kids Toothpaste^®, Pediflor Kids Toothpaste^®, and Crest Pro-Health Stages Kids Toothpaste^® and distilled water as control group were subjected for antifungal activity of C. albicans. Agar plates were incubated at 37°C for 48 h, and the diameter of the zones of inhibition was measured and recorded. Data were tabulated and statistical analysis was done using Statistical Package for the Social Science (16.0) version.

RESULTS

Pediflor kids toothpaste® showed maximum antifungal activity and Aloe Dent children's toothpaste® showed minimum antifungal activity.

CONCLUSION

All brands of children's toothpaste show antifungal activity against Candida albicans.

Candida biome of severe early childhood caries (S-ECC) and its cariogenic virulence traits

The protected niche of deep-caries lesions is a distinctive ecosystem. We assessed the Candida biome and its cariogenic traits from dentin samples of 50 children with severe-early childhood caries (S-ECC). Asymptomatic, primary molars belonging to International Caries Detection and Assessment-ICDAS caries-code 5 and 6 were analyzed, and C. albicans (10-isolates), C. tropicalis (10), C. krusei (10), and C. glabrata (5) isolated from the lesions were then evaluated for their biofilm formation, acidogenicity, and the production of secreted hydrolases: hemolysins, phospholipase, proteinase and DNase. Candida were isolated from 14/43 ICDAS-5 lesions (32.5%) and 44/57 ICDAS-6 lesions (77.2%). Compared to, ICDAS-5, a significantly higher frequency of multi-species infestation was observed in ICDAS-6 lesions (p=0.001). All four candidal species (above) showed prolific biofilm growth, and an equal potency for tooth demineralization. A significant interspecies difference in the mean phospholipase, as well as proteinase activity was noted (p < 0.05), with C. albicans being the predominant hydrolase producer. Further, a positive correlation between phospholipase and proteinase activity of Candida-isolates was noted (r = 0.818, p < 0.001). Our data suggest that candidal mycobiota with their potent cariogenic traits may significantly contribute to the development and progression of S-ECC.

Activity of sodium trimetaphosphate, associated or not with fluoride, on dual-species biofilms

This study aimed to evaluate the effect of sodium trimetaphosphate (TMP), either with fluoride (F) or without fluoride, on dual-species biofilms of Streptococcus mutans and Candida albicans. The 72 h biofilms were treated with 0.25%, 0.5%, or 1% TMP solutions, combined or not with 500 ppm F, and analysed by quantification of viable plate counts, metabolic activity, biomass, and extracellular matrix components. Biofilm structure was evaluated by scanning electron microscopy (SEM). TMP significantly reduced the number of S. mutans cells and biomass only when associated to F. Furthermore, fluoride-free TMP promoted significant reductions in biofilm metabolism, while all the tested solutions decreased the contents of the biofilm matrix compared to untreated groups. Regarding biofilm structure, TMP associated with F led to the formation of a less compact biofilm. It was concluded that TMP alone had a reducing effect, mainly on the metabolism and the extracellular matrix components of the biofilms.

Cross-kingdom interaction of Candida albicans and Actinomyces viscosus elevated cariogenic virulence

OBJECTIVE

How the interactions between Candida albicans and Actinomyces viscosus contributed to the root caries was not clear. This study aimed to investigate their cross-kingdom interactions on the biomass and the cariogenic virulence in dual-species biofilms.

DESIGN

Suspensions of C. albicans and A. viscosus were formed the mono and polymicrobial biofilms in vitro. Crystal violet assay, viable plate count, scanning electron microscopy and fluorescence in situ hybridization were used to analyze the biomass and biofilm structure. Glycolytic pH drop and the spectrophotometric method were used to evaluate the acid production and hydroxyapatite dissolution, respectively. The exopolysaccharide production was measured by the anthrone-sulfuric acid method, while the adhesion force was measured by atomic force microscopy.

RESULTS

The biomass and colony-forming units of mixed-species were significantly increased compared to that of the mono-species at 24 h, 48 h, 72 h. The structure of dual-species biofilm had more microcolonies and was much denser. The dual-species biofilms significantly decreased the pH value and damaged the hydroxyapatite compared with the mono-species biofilms at various time points, indicating the strong cariogenic virulence. Moreover, the dual-species biofilms significantly enhanced the exopolysaccharide production and adhesion force suggesting the increase of biofilm adhesion.

CONCLUSIONS

Cross-kingdom interactions of C. albicans and A. viscosus significantly elevated the biomass and cariogenic virulence of dual-species biofilm.

Anti-fungal bandages containing cinnamon extract

Cinnamon‐containing polycaprolactone (PCL) bandages were produced by pressurised gyration and their anti‐fungal activities against Candida albicans were investigated. It was found that by preparing and spinning polymer solutions of cinnamon with PCL, fibres capable of inhibiting fungal growth could be produced, as observed in disk diffusion tests for anti‐fungal susceptibility. Fascinatingly, compared with raw cinnamon powder, the novel cinnamon‐loaded fibres had outstanding long‐term activity. The results presented here are very promising and may indeed accelerate a new era of using completely natural materials in biomedical applications, especially in wound healing.

Candida albicans Increases Dentine Demineralization Provoked by Streptococcus mutans Biofilm

Streptococcus mutans are considered the most cariogenic bacteria, but it has been suggested that Candida albicans could increase their cariogenicity. However, the effect of this dual-species microorganisms' combination on dentine caries has not been experimentally evaluated. Biofilms of C. albicans, S. mutans and C. albicans + S. mutans (n = 12/biofilm) were grown in ultra-filtered tryptone yeast extract broth culture medium for 96 h on root dentine slabs of known surface hardness and exposed 8 times per day for 3 min to 10% sucrose. The medium was changed 2 times per day (after the 8 cariogenic challenges and after the overnight period of famine), and aliquots were analyzed to determinate the pH (indicator of biofilm acidogenicity). After 96 h, the biofilms were collected to determine the wet weight, colony-forming units, and the amounts of extracellular polysaccharides (soluble and insoluble). Dentine demineralization was assessed by surface hardness loss (% SHL). The architecture of the biofilms was analyzed by confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Data were analyzed by ANOVA followed by Tukey's test (α = 0.05). The dual-species C. albicans + S. mutans biofilm provoked higher % SHL on dentine (p < 0.05) than the S. mutans and C. albicans biofilm. This was supported by the results of biofilm acidogenicity and the amounts of soluble (6.4 ± 2.14 vs. 4.0 ± 0.94 and 1.9 ± 0.97, respectively) and insoluble extracellular polysaccharides (24.9 ± 9.22 vs. 18.9 ± 5.92 and 0.7 ± 0.48, respectively) (p < 0.05). The C. albicans biofilm alone presented low cariogenicity. The images by CLSM and TEM, respectively, suggest that the C. albicans + S. mutans biofilm is more voluminous than the S. mutans biofilm, and S. mutans cells interact with C. albicans throughout polysaccharides from the biofilm matrix. These findings show that C. albicans enhances the cariogenic potential of the S. mutans biofilm, increasing dentine demineralization.

Preliminary study of the oral mycobiome of children with and without dental caries

Children’s oral health is in a dire state, with dental decay (caries) being one of the most common chronic diseases. While the role of bacteria in the oral microbiome and dental caries is established, the contribution of fungi is relatively unknown. We assessed the oral mycobiome in childhood (n = 17), to determine if the composition of fungi varies between children with and without caries. Oral mycobiome composition was assessed by using Illumina MiSeq to sequence the ITS2 region, which was amplified from dental plaque. This revealed that the oral mycobiome in the investigated children contained 46 fungal species. Candida albicans was the most abundant species and was ubiquitous in all samples, indicating this species may not be involved in caries development as previously suggested. While the overall diversity of fungi was similar, independent of caries status (p > 0.05), we found caries influenced the abundance of specific fungi. Children without caries had a significantly higher abundance of 17 species compared to children with caries, which had three enriched species (p < 0.001). While the differentially abundant species between health and caries may be specific to an Australian population, our findings indicate the mycobiome plays a role in oral health.

Association between Oral Candida and Bacteriome in Children with Severe ECC

Candida albicans is an opportunistic fungal organism frequently detected in the oral cavity of children with severe early childhood caries (S-ECC). Previous studies suggested the cariogenic potential of C. albicans, in vitro and in vivo, and further demonstrated its synergistic interactions with Streptococcus mutans. In combination, the 2 organisms are associated with higher caries severity in a rodent model. However, it remains unknown whether C. albicans influences the composition and diversity of the entire oral bacterial community to promote S-ECC onset. With 16s rRNA amplicon sequencing, this study analyzed the microbiota of saliva and supragingival plaque from 39 children (21 S-ECC and 18 caries-free [CF]) and 33 mothers (17 S-ECC and 16 CF). The results revealed that the presence of oral C. albicans is associated with a highly acidogenic and acid-tolerant bacterial community in S-ECC, with an increased abundance of plaque Streptococcus (particularly S. mutans) and certain Lactobacillus/Scardovia species and salivary/plaque Veillonella and Prevotella, as well as decreased levels of salivary/plaque Actinomyces. Concurrent with this microbial community assembly, the activity of glucosyltransferases (cariogenic virulence factors secreted by S. mutans) in plaque was significantly elevated when C. albicans was present. Moreover, the oral microbial community composition and diversity differed significantly by disease group (CF vs. S-ECC) and sample source (saliva vs. plaque). Children and mothers within the CF and S-ECC groups shared microbiota composition and diversity, suggesting a strong maternal influence on children's oral microbiota. Altogether, this study underscores the importance of C. albicans in association with the oral bacteriome in the context of S-ECC etiopathogenesis. Further longitudinal studies are warranted to examine how fungal-bacterial interactions modulate the onset and severity of S-ECC, potentially leading to novel anticaries treatments that address fungal contributions.

Superhydrophilic co-polymer coatings on denture surfaces reduce Candida albicans adhesion-An in vitro study

OBJECTIVE

In this study, we aimed to investigate denture-base-resin coatings prepared with a crosslinkable co-polymer containing sulfobetaine methacrylamide (SBMAm) and the relationship between their surface characteristics and the initial adhesion of Candida albicans (C. albicans).

METHODS

Acrylic resin discs were coated with co-polymers containing various concentrations of SBMAm and N,N'-(4,7,10-trioxa-1,13-tridecadiamine) diacrylamide (JDA) as crosslinking agent. Uncoated discs were used as controls. An acquired pellicle was formed on each disc using artificial saliva, and the discs were immersed in a suspension of C. albicans (JCM2085) cells. After incubation, tetrazolium salt (XTT-reduction) and colony forming unit (CFU) assays were performed and the morphogenesis of C. albicans was examined using scanning electron microscopy (SEM). The surface roughness, film thickness, and the water contact angle of each disc surface were measured.

RESULTS

All coating groups showed significantly lower amounts of adhered C. albicans in the XTT-reduction and CFU assays than the control, confirmed by the SEM images. Many wrinkle structures were observed on the surfaces coated with co-polymers containing more than 30% SBMAm. There were no significant differences in surface roughness among all groups. The co-polymer films on the coated discs were less than 5.0 μm in thickness, and these surfaces exhibited significantly lower mean water contact angles than the control.

CONCLUSION

Crosslinkable co-polymers containing SBMAm can enhance the hydrophilicity of the surface of denture-base resins and reduce the initial adhesion of C. albicans.

Candida albicans and Early Childhood Caries: A Systematic Review and Meta-Analysis

Oral Candida albicans has been detected in children with early childhood caries (ECC) and has demonstrated cariogenic traits in animal models of the disease. Conversely, other studies found no positive correlation between C. albicans and caries experience in children, while suggesting it may have protective effects as a commensal organism. Thus, this study aimed to examine whether oral C. albicans is associated with ECC. Seven electronic databases were searched. The data from eligible studies were extracted, and the risk of bias was evaluated. A fixed effects model (Mantel-Haenszel estimate) was used for meta-analysis, and the summary effect measure was calculated by odds ratio (OR) and 95% confidence interval (CI). Fifteen cross-sectional studies were included for the qualitative assessment and 9 studies for meta-analysis. Twelve studies revealed higher oral C. albicans prevalence in ECC children than in caries-free children, while 2 studies indicated an equivalent prevalence. A pooled estimate, with OR = 6.51 and 95% CI = 4.94-8.57, indicated a significantly higher ECC experience in children with oral C. albicans than those without C. albicans (p < 0.01). The odds of experiencing ECC in children with C. albicans versus children without C. albicans were 5.26 for salivary, 6.69 for plaque, and 6.3 for oral swab samples. This systematic review indicates that children with oral C. albicans have >5 times higher odds of having ECC compared to those without C. albicans. Further prospective cohort studies are needed to determine whether C. albicans could be a risk factor for ECC, and whether it is dependent on different sample sources (saliva/plaque).

Is the oral fungal pathogen Candida albicans a cariogen?

Pathobiology of dental caries is complex. Data from recent molecular microbiologic studies have further redefined the role of the oral microbiome in the etiology of dental caries. This new information challenges the conventional view on the hegemony of classic cariogenic prokaryotes such as Streptococcus mutans in caries etiology, and raises the intriguing possibility of the participation of the eukaryotic oral fungal pathogen Candida in the caries process. The virulence attributes of Candida species such as their acidogenicity and aciduric nature, the ability to develop profuse biofilms, ferment and assimilate dietary sugars, and produce collagenolytic proteinases are all indicative of their latent cariogenic potential. Based on the above, oral candidal counts have been used by some as a caries risk indicator. On the contrary, other studies suggest that Candida is merely a passenger extant in an acidic cariogenic milieu, and not a true pathogen. In this review, we critically examine the varying roles of Candida, and traditionally accepted cariogens such as the mutans group of streptococci in the pathobiology of dental caries. The weight of available data tends to imply that Candida may play a pivotal role as a secondary agent perpetuating the carious process, especially in dentinal caries.

Denaturing gradient gel electrophoresis profiles of bacteria from the saliva of twenty four different individuals form clusters that showed no relationship to the yeasts present

OBJECTIVES

The aim was to investigate the relationship between groups of bacteria identified by cluster analysis of the DGGE fingerprints and the amounts and diversity of yeast present.

METHODS

Bacterial and yeast populations in saliva samples from 24 adults were analysed using denaturing gradient gel electrophoresis (DGGE) of the bacteria present and by yeast culture.

RESULTS

Eubacterial DGGE banding patterns showed considerable variation between individuals. Seventy one different amplicon bands were detected, the band number per saliva sample ranged from 21 to 39 (mean±SD=29.3±4.9). Cluster and principal component analysis of the bacterial DGGE patterns yielded three major clusters containing 20 of the samples. Seventeen of the 24 (71%) saliva samples were yeast positive with concentrations up to 10³cfu/mL. Candida albicans was the predominant species in saliva samples although six other yeast species, including Candida dubliniensis, Candida tropicalis, Candida krusei, Candida guilliermondii, Candida rugosa and Saccharomyces cerevisiae, were identified. The presence, concentration, and species of yeast in samples showed no clear relationship to the bacterial clusters.

CONCLUSION

Despite indications of in vitro bacteria-yeast interactions, there was a lack of association between the presence, identity and diversity of yeasts and the bacterial DGGE fingerprint clusters in saliva. This suggests significant ecological individual-specificity of these associations in highly complex in vivo oral biofilm systems under normal oral conditions.

Role of Candida species from HIV infected children in enamel caries lesions: an in vitro study

Objectives

This study analyzed the capacity of Candida spp. from dental biofilm of HIV infected (HIV+) children to demineralize primary molar enamel in vitro by Transversal Microhardness (TMH), Polarized Light Microscopy (PLM) and the quantity of calcium ions (Ca²⁺) released from the enamel.

Material and Methods

Candida spp. samples were isolated from the supragingival biofilm of HIV+ children. A hundred and forty (140) enamel blocks were randomly assigned to six groups: biofilm formed by C. albicans (Group 1); mixed biofilm formed by C. albicans and C. tropicalis (Group 2); mixed biofilm formed by C. albicans and C. parapsilosis (Group 3); mixed biofilm formed by C. albicans, C. parapsilosis and C. glabrata (Group 4); biofilm formed by C. albicans ATCC (Group 5) and medium without Candida (Group 6). Enamel blocks from each group were removed on days 3, 5, 8 and 15 after biofilm formation to evaluate the TMH and images of enamel were analyzed by PLM. The quantity of Ca²⁺ released, from Groups 1 and 6, was determined using an Atomic Absorption Spectrophotometer. The SPSS program was used for statistical analysis and the significance level was 5%.

Results

TMH showed a gradual reduction in enamel hardness (p<0.05) from the 1^st to 15^th day, but mainly five days after biofilm formation in all groups. The PLM showed superficial lesions indicating an increase in porosity. C. albicans caused the release of Ca²⁺ into suspension during biofilm formation.

Conclusion

Candida species from dental biofilm of HIV+ children can cause demineralization of primary enamel in vitro.

The Oral Microbiome in Health and Its Implication in Oral and Systemic Diseases

The oral microbiome can alter the balance between health and disease, locally and systemically. Within the oral cavity, bacteria, archaea, fungi, protozoa, and viruses may all be found, each having a particular role, but strongly interacting with each other and with the host, in sickness or in health. A description on how colonization occurs and how the oral microbiome dynamically evolves throughout the host's life is given. In this chapter the authors also address oral and nonoral conditions in which oral microorganisms may play a role in the etiology and progression, presenting the up-to-date knowledge on oral dysbiosis as well as the known underlying pathophysiologic mechanisms involving oral microorganisms in each condition. In oral pathology, oral microorganisms are associated with several diseases, namely dental caries, periodontal diseases, endodontic infections, and also oral cancer. In systemic diseases, nonoral infections, adverse pregnancy outcomes, cardiovascular diseases, and diabetes are among the most prevalent pathologies linked with oral cavity microorganisms. The knowledge on how colonization occurs, how oral microbiome coevolves with the host, and how oral microorganisms interact with each other may be a key factor to understand diseases etiology and progression.

Association of Oral Candida albicans with Severe Early Childhood Caries - A Pilot Study

INTRODUCTION

In early childhood, children are more susceptible to opportunistic microbial colonization in the oral cavity due to immature immune system and not fully established micro flora. The current literature proposes a probable role of Candida albicans, a fungus in the etiopathogenesis of dental caries.

AIM

This study was conducted to compare the Candida albicans count in children with severe early childhood caries and caries free children.

MATERIALS AND METHODS

A cross-sectional study was conducted in 40 randomly selected healthy children between 12 to 71 months of age, who were divided into two groups based on the caries experience as Severe Early Childhood Caries (SECC) (dmfs ≥4) and caries free (dmfs = 0). The caries experiences (dmfs index) of the 40 children were recorded using visible light and diagnostic instruments. A 2ml sample of unstimulated whole saliva collected from the children was transported to the microbiology laboratory in universal containers and evaluated for Candida albicans count using the selective media. The data was statistically analyzed using SPSS software 17.0.

RESULTS

Candida albicans was found in both the SECC group and caries free group. Median Candida albicans of the SECC group was numerically greater than the caries free group and this difference was highly statistically significant (p=0.012).

CONCLUSION

In this present cross-sectional study, we found a 100% prevalence of Candida albicans in the saliva of the study children. There was a highly significant increase in Candida albicans count in SECC children compared to the caries free children.

Quantification and Correlation of Oral Candida with Caries Index Among Different Age Groups of School Children: A Case-Control Study

Background:

Dental caries is the most common infectious disease affecting humans and is the predominant cause of tooth loss in children. Although Candida's role in dental caries has been studied extensively, limited homogenous studies have been conducted and none have been found, that associate Candida with dental caries, while correlating it to different age groups.

Aim:

The study aimed to quantify oral Candida in school children and correlate candidal carriage to the caries index and further analyze an age association.

Subjects and Methods:

Decayed-Filled teeth/Decayed-Missing-Filled Teeth (dft/DMFT) index scores of 150 subjects were evaluated, and concentrated oral rinse samples were collected from each participant for mycologic investigation. Based on the age and caries activity, the participants were categorized into three groups consisting of 50 each such as Group-I (caries active participants of 6–12 years age), Group-II (caries active participants in 13–18 years age), and Group-III (caries-free participants in 6–18 years age); CHROMagar™ was used as a primary culture medium for candidal growth. The data was statistically analyzed using Unpaired t-test, Chi-square test and Spearman's rank order.

Results:

The results demonstrated that as age increases, the dft/DMFT scores as well as the candidal growth decreased. In addition, the oral candidal carriage levels were found to be low in caries-free group (Group-III) when compared to the study groups.

Conclusion:

The presence of Candida was directly related to the caries status and inversely proportional to the age.

Antimicrobial peptides in saliva of children with severe early childhood caries

OBJECTIVE

Controversies exist regarding the relationship between the concentrations of antimicrobial peptides (AMPs) and presence of dental caries in children. Thus, the aim of this study was to examine levels of AMPs in saliva of caries-free (CF), early childhood caries (ECC) and severe early childhood caries (S-ECC) children to determine if the levels of these salivary peptides individually or in combinations were related to caries severity and mutans streptococci levels.

DESIGN

36 to 60 month-old children were selected to participate in this study. Children were grouped into CF group (n=29), ECC group (n=25) and S-ECC group (n=29). Saliva was collected from children for microbiological analysis by culture. Salivary concentrations of cathelicidin LL-37, human β-defensin 2 (hBD-2), human β-defensin 3 (hBD-3) and histatin-5 (HTN-5) were determined by ELISA.

RESULTS

Salivary concentrations of AMPs did not differ among CF, ECC and S-ECC groups. Data showed positive correlations between mutans streptococci levels and salivary hBD-2 or HTN-5. Positive correlations were found between hBD-2, hBD-3, LL-37 and HTN-5. Combinations among AMPs, mainly LL-37, were positively associated with caries levels.

CONCLUSIONS

Salivary concentrations of AMPs individually were not associated with the severity of early childhood caries. The stimulus of caries appears to trigger a biological response, however, with a combination of these peptides.

Genotypes and virulence factors of Candida species isolated from oralcavities of patients with type 2 diabetes mellitus

BACKGROUND/AIM

This study compared the genotypes and virulence factors of Candida species isolated from oral cavities of healthy individuals and patients with diabetes mellitus (DM).

MATERIALS AND METHODS

A total of 142 healthy individuals and 73 diabetic patients participated in this study. Study populations were classified into 4 groups as follows: Group I - Healthy, without caries; Group II - Healthy, with caries; Group III - DM, with caries; Group IV - DM, without caries. Diabetic patients' blood glucose and hemoglobin A1c concentrations were determined. Identification of Candida species was performed with conventional methods. Biofilm production, proteinase, phospholipase, and esterase were analyzed. The genetic diversity of Candida species was established using rep-PCR.

RESULTS

The most isolated species was Candida albicans. There were statistical differences in terms of isolated Candida frequency between healthy subjects and diabetic patients. There was no statistical difference between the virulence factors of groups. Twelve genotypes were determined. While there were statistical differences in aerobe biofilm production, proteinase, and phospholipase activity between genotypes, there were no statistical differences in anaerobe biofilm production and esterase activity between genotypes.

CONCLUSION

Diabetes has no effect on the activities of virulence factors of Candida species. Different genotypes of Candida albicans exhibited different virulence activities.

Genotypic diversity and cariogenicity of Candida albicans from children with early childhood caries and caries-free children

BACKGROUND

The genotypic diversity and cariogenicity of C. albicans from the dental plaque of children are poorly understood. This study aimed to explore the genotypic diversity and cariogenicity of C. albicans from children with early childhood caries and caries-free children.

METHODS

Dental plaque samples from 238 children with early childhood caries and from 125 caries-free children were collected for C. albicans isolation. A PCR method based on 25S rDNA was used to analyze C. albicans genotypes, and the strains with different genotypes were tested with regard to acidogenicity and aciduricity.

RESULTS

Among 129 C. albicans isolates, 79 (61.2 %) belonged to genotype A. The distribution frequency of genotypes A and C or genotypes B and C showed no significant difference between children with early childhood caries and caries-free children (p = 0.178 and 0.148), whereas genotypes A and B exhibited significantly different distributions (p = 0.010). No significant differences in aciduricity were found among the three genotypes, but the acidogenicity of genotypes B and C differed significantly from that of genotype A at pH 4.0.

CONCLUSIONS

The genotypic distribution of C. albicans is associated with the caries experience of children, and the genotype may be related to its acidogenicity at pH 4.0.

Evaluation of caries-associated virulence of biofilms from Candida albicans isolated from saliva of pediatric patients with sickle-cell anemia

A previous study demonstrated that the amount of Candida spp. in saliva is higher in children with sickle-cell disease. The results from a recent study demonstrate its participation in the etiology of dental caries.

Linear reciprocal interaction between dental caries and salivary characteristics

Carious tooth surfaces can alter saliva in various ways. We investigated whether salivary parameters were affected by elimination of existing active dental caries in 99 children (age 6-12 years) with more than five carious tooth surfaces. Unstimulated saliva samples were obtained from each child, and salivary characteristics were evaluated. One month after caries treatment that eliminated all existing dental caries, saliva sampling and analysis were repeated. Saliva viscosity significantly decreased (P = 0.04), while pH and saliva buffering capacity significantly increased (P < 0.001). There was no significant difference in unstimulated salivary production at the start of the study and 1 month after caries elimination (P > 0.05). The relationship between dental caries and salivary condition is reciprocal. Treatment of existing dental caries can prevent future caries by improving saliva quality.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

Background

With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).

Methods

Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.

Results

In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).

Conclusions

All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.

Differential collagenolytic activity of Candida albicans isolated from oral mucosa and dentinal carious lesions of HIV-infected children

OBJECTIVE

The aim of this study was to compare type I collagen degradation by Candida albicans isolated from oral mucosa (M) and cavitated active dentinal caries (CAD) of HIV-infected children.

STUDY DESIGN

To verify the proteolytic activity, the specimens were cultivated in brain-heart infusion medium and the supernatants were incubated in the presence or absence of type I collagen at 37°C for 12 hours and analyzed using 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Intensity of the bands on the gels was assessed by densitometric analysis using a scanner and images analyzed with software from Kodak Digital Science EDAS 120.

RESULTS

Supernatants of all the C. albicans degraded type I collagen: that from M, on average, by 38.3% (SD 21.67) and that from CAD by 54% (SD 25.94; Wilcoxon test: P < .05). Predisposing factors had no association with the percentage of type I collagen degradation (Mann-Whitney test: P > .05).

CONCLUSIONS

Candida albicans from different sites of the oral cavity of HIV-infected children has proteolytic activity for type I collagen.

Genotypic distribution of Candida albicans in dental biofilm of Chinese children associated with severe early childhood caries

AIM

Candida albicans causes a wide range of infections in the oral mucosa, especially candidiasis. A strong association has been found between C. albicans and dental caries. In this study, we investigated the presence and genotypic distribution of C. albicans in the dental biofilm of Chinese children with severe early childhood caries (S-ECC).

DESIGN

Dental biofilm samples were collected from 41 Chinese children (21 children with S-ECC and 20 children without caries) aged 3-6 years. Samples collected were cultured in CHROMagar Candida (CA) medium. Cellular DNA of typical C. albicans isolates in the CA medium was isolated, and PCR using primers reported to span a transposable intron region in the 25S rRNA gene was performed to determine genotypic subgroups.

RESULTS

C. albicans was detected in 57.1% of individuals with S-ECC. Additionally, three genotypic subgroups of C. albicans (genotypes A, B, and C) were found in children with S-ECC, and genotype A was dominant.

CONCLUSIONS

C. albicans is an important component of dental biofilm associated with S-ECC, and C. albicans genotypic subgroup A is the dominant strain in the dental biofilm of children with S-ECC.

Influence of cigarette smoke condensate on cariogenic and candidal biofilm formation on orthodontic materials

INTRODUCTION

An experimental analysis was made to quantify the adherence rates and the biofilm formation capacity of Streptococcus mutans ATCC25175 and Candida albicans SC5314 on orthodontic material surfaces in the presence of cigarette smoke condensate (CSC).

METHODS

Metal brackets, bands, acrylic resin, and polyurethane elastic rings were coated with stimulated saliva and submitted to adhesion and biofilm formation tests with and without CSC in a dynamic system.

RESULTS

The CSC increased the adhesion of S mutans ATCC25175 to the acquired pellicle (P <0.05) for bands (4.08 times), acrylic resin (2.89 times), and brackets (3.37 times) and reduced it in polyurethane elastic (2.66 times; P <0.05). S mutans ATCC25175 biofilm biomass was increased by CSC only on brackets (1.60 times; P <0.05). In the presence of CSC, the adhesion of C albicans SC5314 increased (P <0.05) on bands (1.81 times), brackets (9.61 times), elastics (29,133 times), and acrylic resin (177 times). Greater formation of C albicans SC5314 biofilm caused by CSC (P <0.05) was observed on acrylic resin (2.13 times) and brackets (2.32 times).

CONCLUSIONS

The results indicated that cigarette tobacco smoke can interfere with the adhesion and biofilm formation of these microorganisms to various orthodontic materials.

Effect of substrate surface hydrophobicity on the adherence of yeast and hyphal Candida

A biofilm composed of various microorganisms including Candida is found on denture surfaces and is likely to be involved in the etiology of denture-induced stomatitis. The purpose of this study was to examine the role of hydrophobic interactions in candidal adherence to acrylic surfaces, particularly that of the hyphal form of Candida albicans. Candida clinical isolates were used. Acrylic plates coated with carrageenan and hydrocolloid (Hitachi chemical, Tokyo, Japan) were used as a hydrophilic substratum. A microbial suspension was placed on each acrylic plate and incubated. All plates were washed in phosphate-buffered saline containing CaCl(2) and MgCl(2) [PBS (+)] and cells still adhering to the acrylic surface were collected by 0.25% trypsin treatment. Cell-surface hydrophobicity was estimated using a modification of the technique used to measure adherence to hydrocarbons. When the acrylic plates were coated with hydrophilic materials, the adherence of hydrophobic clinical isolates of Candida and the hydrophobic hyphal C. albicans decreased, whereas the adherence of non-hydrophobic Candida was not affected or increased. We suggest that hydrophilic coating of denture surfaces could be a potent method for reduction of the adherence of relatively hydrophobic fungal cells, particularly hyphal C. albicans, which causes denture stomatitis and related infections.

The microbiological profiles of saliva, supragingival and subgingival plaque and dental caries in adults with and without type 2 diabetes mellitus

INTRODUCTION

The relationships between suspected bacteria in saliva, yeasts in oral rinse, and supragingival and subgingival plaque versus root surface and coronal caries in adults with type 2 diabetes mellitus and a non-diabetic group were explored.

METHODS

One-hundred and five patients with type 2 diabetes and 103 non-diabetic subjects were recruited; their periodontal status, plaque index and magnitude of root surface and coronal caries were assessed. Saliva and an oral rinse were cultured for mutans streptococci, lactobacilli and yeasts. Toothbrush samples of supragingival plaque and curette samples of subgingival plaque were assessed for 17 bacterial species using the checkerboard DNA-DNA hybridization method.

RESULTS

Type 2 diabetes patients had significantly more severe periodontitis, a higher plaque index and a higher prevalence and magnitude of root surface caries than non-diabetic subjects. Significantly more diabetic subjects had higher levels of Treponema denticola, Prevotella nigrescens, Streptococcus sanguinis, Streptococcus oralis and Streptococcus intermedius in their supragingival plaque than non-diabetic subjects. No significant difference was found for the organisms in saliva, oral rinse and subgingival plaque between the two groups. After adjustment for diabetic status, root surface caries was associated with an increased count of mutans streptococci, lactobacilli and yeasts in saliva and of Streptococcus mutans in supragingival plaque samples. Coronal caries was only associated with lactobacilli and yeasts in saliva.

CONCLUSION

The number of cariogenic organisms in saliva and oral rinse estimated by culture demonstrated a stronger association with both root surface and coronal caries compared to those 17 species assessed with the checkerboard method in supragingival and subgingival plaque.

Candida albicans does not invade carious human dentine

AIM

Candida albicans has been proposed to be a caries pathogen, but the evidence for its specific role is lacking. To be considered significant in caries progression, a marked amount of yeasts should be present in a lesion. The aim of the study was to investigate the presence of C. albicans in dentinal caries lesions.

MATERIALS AND METHODS

To demonstrate the extension of caries and to identify the bacteria in a lesion, sections of 10 carious human teeth were stained with Gram and Giemsa stains. C. albicans was detected with periodic acid-Schiff (PAS) staining and by immunohistochemistry using a C. albicans-specific antibody 3H8. Thirty sections were used for each staining (in total 120 sections).

RESULTS

Extensive bacterial invasion and intensive staining by PAS occurred in all samples. However, with the C. albicans-specific antibody, only 30 (3.3%) sections stained weakly positive, with a few stained cells on the lesion surface. However, the positive identification of C. albicans, based on the morphology of the cells, was not possible.

CONCLUSIONS

The results do not support the previous suggestion that C. albicans is important in the dentine caries pathology. In addition, because of its unspecific nature, PAS turned out to be an unsuitable method for detecting yeasts in carious tooth samples.

Microbiota of plaque microcosm biofilms: effect of three times daily sucrose pulses in different simulated oral environments

AIM

To explore the Ecological Plaque Hypothesis for dental caries. To test modification of the microbiota of dental plaque microcosm biofilms by sucrose pulsing during growth in two different simulated oral fluids, and with a urea-induced plaque pH elevation.

METHODS

Plaque microcosm biofilms were cultured in an 'artificial mouth' with and without 6-min 5% w/v sucrose pulses every 8 h in an environment of continuously supplied saliva-like defined medium with mucin (DMM), or basal medium mucin (BMM, a high-peptone-yeast extract oral fluid analogue), and also in DMM + 10 mmol/l urea, with sucrose pulsing. Forty plaque species were quantified by checkerboard DNA:DNA hybridization analysis.

RESULTS

Sucrose pulsing extended rapid plaque growth in DMM and BMM, inducing major microbiota changes in DMM but not in BMM. In DMM, some streptococci and lactobacilli were unaffected while others implicated in caries, together with Candida albicans and Capnocytophaga gingivalis, increased. Aerobic, microaerophilic and major anaerobic species decreased. Elevation of the pH(max) from 6.4 to 7.0 had almost no effect on the microbiota. BMM plaques were distinct from DMM plaques with particularly low levels of Candida albicans and Actinomyces.

CONCLUSIONS

Modest sucrose exposure in a saliva-like environment causes profound changes in the developmental self-organization of plaque microcosms, supporting the Ecological Plaque Hypothesis. Nevertheless, there is significant stability in microbial composition with varying pH near neutrality. Increases in levels of specific bacteria in response to sucrose could be characteristic of organisms particularly important in caries.

Presence of mutans streptococci and Candida spp. in dental plaque/dentine of carious teeth and early childhood caries

This study determined the presence of mutans streptococci and Candida spp. in supragingival dental plaque and infected dentine of caries-free children, with early childhood caries and caries. Pooled samples of dental plaque and infected dentine were collected from 56 children aged 1-5 years, which were divided into 3 groups: early childhood caries (ECC); caries and caries-free. Infected dentine was collected in ECC and caries groups to compare the frequency of these microorganisms in the collected sites. The samples were inoculated in SB20 and SA medium, for mutans streptococci and Candida spp., respectively, and incubated at 37 degrees C for 48 h. Colony growth was verified and the identification was performed by biochemical tests and CHROMagar Candida. Fisher's test or chi-square (chi(2)) were applied (p=0.05). The more prevalent species were S. mutans and Candida albicans in ECC (85.4% and 60.4%, respectively), independently of the sample site. S. mutans only was significantly associated with carious teeth, whether in early childhood caries or not. However, the frequency of C. albicans in ECC was higher when compared to caries and caries-free groups. There is a significant association between the presence of C. albicans and early childhood caries.

Minimum inhibitory concentration of adherence of Punica granatum Linn (pomegranate) gel against S. mutans, S. mitis and C. albicans

The purpose of this study was to investigate the antimicrobial effect of a Punica granatum Linn (pomegranate) phytotherapeutic gel and miconazole (Daktarin® oral gel) against three standard streptococci strains (mutans ATCC 25175, sanguis ATCC 10577 and mitis ATCC 9811), S. mutans clinically isolated and Candida albicans either alone or in association. The effect of minimum inhibitory concentrations of the gels on the adherence of these microorganisms to glass was assessed in the presence of 5% sucrose, using increasing and doubled concentrations of the diluted solution of the gels ranging from 1:1 to 1:1024. The minimum inhibitory concentrations of adherence of Punica granatum L. gel against the test organisms were: 1:16 for S. mutans (ATCC), S. mutans (CI) and S. sanguis; 1:128 for S. mitis and 1:64 for C. albicans. The minimum inhibitory concentrations of adherence of miconazole against the same organisms were: 1:512, 1:64, 1:4, 1:128 and 1:16, respectively. In experiments with three and four associated microorganisms, the Punica granatum L. gel had greater efficiency in inhibiting microbial adherence than the miconazole. The results of this study suggest that this phytotherapeutic agent might be used in the control of adherence of different microorganisms in the oral cavity.