Boonyanit Thaweboon

Effect of Phyllanthus emblica Linn. on candida adhesion to oral epithelium and denture acrylic.

OBJECTIVE To investigate the effect of Phyllanthus emblica (P. emblica) Linn. ethanolic extract on the adhesion of Candida albicans (C. albicans) to human buccal epithelial cells (BECs) and denture acrylic surfaces. METHODS Human BECs and transparent acrylic strips were pretreated with ethanolic extract solution of P. emblica fruits at concentration ranged from 18.7 to 300 mg/mL. After washing BECs and the strips were inoculated with three strains of C. albicans (ATCC 10281 and two clinical isolates) (10(7) cells/mL). Normal saline solution (NSS) and 0.2% chlorhexidine gluconate were used as negative and positive controls, respectively. BECs were harvested on 12 μm-polycarbonate filters (Millipore, USA). The membrane filters and the strips were stained with Gram stain. Adherent yeast cells on 100 randomly selected epithelial cells and 20 randomly selected fields on each strip were counted under microscope. The statistical significance was calculated by Kruskal-Wallis and Tukey tests at a significant level of P< 0.05. RESULTS Significant lower numbers of all strains of yeasts adhering to BECs and acrylic strips were observed after exposure to 75-300 mg/mL of plant extract compared with NSS. CONCLUSIONS The present study demonstrates that P. emblica ethanolic extract interferes with the adhesion of C. albicans to BECs and denture acrylic surfaces in vitro.

Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

OBJECTIVE To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. METHODS The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candida albicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. RESULTS All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5-3.0 µm) and more uniformly shaped than AgZ. CONCLUSIONS Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

Clinical and laboratory assessments of camphorated monochlorophenol in endodontic therapy

The purpose of this study was to evaluate the effect of camphorated monochlorophenol (CMCP) on bacterial status of root canals of nonvital teeth during treatments. The presence of bacteria in 15 single-rooted teeth with periapical lesions was studied throughout a whole period of treatment. Patients were randomly divided into three groups. In group 1, a control group, the intracanal medication was omitted. The teeth were enlarged under aseptic conditions in combination with the use of 3% H2O2 and 5.25% NaOCl as irrigants. In group 2, after chemomechanical preparation, the root canals were dressed with 2 microliter of 40% CMCP. The medicament was replaced on days 3 and 7. In group 3, root canals were treated in a manner similar to those in group 2, except that the medicament was renewed on days 1 and 7. The loss of CMCP was determined in groups 2 and 3. The results showed that chemomechanical preparation could reduce bacteria in root canals to an uncultivable number. Approximately 62.5% of the original concentration of CMCP was lost after placement in root canals for 1 day. Intracanal dressing with CMCP between appointments induced a rapid decrease in number of bacteria in root canals within the first 1 to 3 days. However, compared to chemomechanical preparation, the antimicrobial effect of CMCP was not clinically impressive because negative cultures also could be observed despite the absence of intracanal medications.

In vitro effects of Salvia officinalis L. essential oil on Candida albicans.

OBJECTIVE To determine the anticandidal activities of Salvia officinalis L. (S. officinalis) essential oil against Candida albicans (C. albicans) and the inhibitory effects on the adhesion of C. albicans to polymethyl methacrylate (PMMA) resin surface. METHODS Disc diffusion method was first used to test the anticandidal activities of the S. officinalis L. essential oil against the reference strain (ATCC 90028) and 2 clinical strains of C. albicans. Then the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were determined by modified membrane method. The adhesion of C. albicans to PMMA resin surface was assessed after immersion with S. officinalis L. essential oil at various concentrations of 1×MIC, 0.5×MIC and 0.25×MIC at room temperature for 30 min. One-way ANOVA was used to compare the Candida cell adhesion with the pretreatment agents and Tukeys test was used for multiple comparisons. RESULTS S. officinalis L. essential oil exhibited anticandidal activity against all strains of C. albicans with inhibition zone ranging from 40.5 mm to 19.5 mm. The MIC and MLC of the oil were determined as 2.780 g/L against all test strains. According to the effects on C. albicans adhesion to PMMA resin surface, it was found that immersion in the essential oil at concentrations of 1×MIC (2.780 g/L), 0.5×MIC (1.390 g/L) and 0.25×MIC (0.695 g/L) for 30 min significantly reduced the adhesion of all 3 test strains to PMMA resin surface in a dose dependent manner (P<0.05). CONCLUSIONS S. officinalis L. essential oil exhibited anticandidal activities against C. albicans and had inhibitory effects on the adhesion of the cells to PMMA resin surface. With further testing and development, S. officinalis essential oil may be used as an antifungal denture cleanser to prevent candidal adhesion and thus reduce the risk of candida-associated denture stomatitis.

The effects of silane-SiO2 nanocomposite films on Candida albicans adhesion and the surface and physical properties of acrylic resin denture base material

STATEMENT OF PROBLEM Polysiloxane has been used as a coupling material in restorative dental materials for several decades. However, few studies are available on the application of polysiloxane in other dental prosthesis functions. PURPOSE The purpose of this study was to investigate the effects of silane-SiO2 nanocomposite films on Candida albicans adhesion and the surface and physical properties of acrylic resin denture base materials. MATERIAL AND METHODS Specimens were separated into 2 groups, uncoated and coated. They were coated with a film by using the dip-coating method. Specimens were incubated with Candida albicans 10(7) cells/mL for 1 hour, and the adherent cells were counted under an optical microscope. The following surface properties were measured: surface chemical composition with Fourier-transform infrared spectrometry, surface roughness with a surface profiler, surface energy with the sessile drop method, and surface hardness with a microhardness tester. The physical properties, including water sorption, water solubility, ultimate flexural strength, and flexural modulus, were evaluated according to International Organization for Standardization 20795-1 requirements. The adhesion of Candida albicans and the surface properties of the specimens were investigated after cleaning with effervescent tablets and brushing. An MTT assay was used to evaluate the coated specimens. The results were statistically analyzed with the Mann-Whitney U test (α=.05). RESULTS A significant reduction in Candida albicans adhesion (P=.002) was observed before cleaning. In addition, the surface energy was comparable (P=.100), the surface hardness increased significantly (P=.008), and the surface roughness remained unchanged (P=.310). After cleaning with effervescent tablets, a significant decrease in Candida albicans adhesion (P=.002) and in surface roughness (P=.008) was observed; however, similar surface energies were measured (P=.100). After cleaning with a toothbrush, the adhesion of Candida albicans was significantly higher on the coated specimen than on the uncoated specimen (P=.004). The surface roughness values were significantly different (P=.008), and the surface energies could not be determined. The coated specimen had a silicon-oxygen-silicon peak instead of an ester bond in the polymethyl methacrylate structure. The coating film reduced the water sorption (P=.008) and water solubility (P=.032), and increased the ultimate flexural strength (P=.008) and flexural modulus (P=.032) of the specimen. The coated specimen also had satisfactory toxicity results. CONCLUSIONS Reduced Candida albicans adhesion was observed on the coated specimens. The polymeric film did not change the surface roughness of the acrylic resin specimen; however, it did slightly reduce the surface energy. The physical properties of the acrylic resin did not decrease after it was coated with the film.

In vitro antimicrobial effects of grape seed extract on peri-implantitis microflora in craniofacial implants

OBJECTIVE To determine the antimicrobial effects of grape seed on peri-implantitis microflora. METHODS The grape seed extract was tested against peri-implantitis microflora most commonly found in craniofacial implants including reference strains of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Candida albicans (C. albicans) and clinical strains of S. aureus, Klebsiella pneumonia (K. pneumonia) and Candida parapsilosis (C. parapsilosis) by disk diffusion test. Minimum inhibitory concentrations (MIC) and minimum cidal concentrations (MCC) were determined using modified agar dilution millpore method. The extract was further combined with polyethylene glycol and propylene glycol, and was tested for antimicrobial effects. RESULTS Grape seed extract showed positive inhibitory effects with S. aureus at MIC of 0.625 mg/mL and MCC of 1.25 mg/mL respectively. However the extracts showed minimal or no reactivity against strains of E. coli, K. pneumonia, C. parapsilosis and C. albicans. The use of grape seed extract in combination with polyethylene glycol and propylene glycol also showed dose dependent inhibitory effect on S. aureus. CONCLUSIONS The results of the study showed that grape seed has potential antimicrobial effects which can be further studied and developed to be used in the treatment of infected skin-abutment interface of craniofacial implants.

Identification of Veillonella Species in the Tongue Biofilm by Using a Novel One-Step Polymerase Chain Reaction Method

Six Veillonella species have been frequently isolated from human oral cavities including infectious sites. Recently, it was reported that diet, smoking, and possibly socioeconomic status can influence the bacterial profile in oral cavities. In addition, oral hygiene habits may also influence oral microbiota in terms of both numbers and diversity of microorganisms. In this study, the identification of Veillonella species in tongue biofilms of Thai children, divided into three groups dependent on their status of oral hygiene. For this, we used a novel one-step PCR method with species-specific primer sets based on sequences of the rpoB gene. As shown in the results, the number of isolates of Veillonella species was 101 strains from only 10 of 89 subjects. However, the total number of bacteria was high for all subjects. Since it was reported in previous studies that Veillonella species were easy to isolate in human tongue biofilms at high numbers, the results obtained in this study may suggest country- or age-specific differences. Moreover, Veillonella species were detected predominantly in subjects who had poor oral hygiene compared to those with good or moderate oral hygiene. From these results, there is a possibility that Veillonella species may be an index of oral hygiene status. Furthermore, V. rogosae was a predominant species in tongue biofilms of Thai children, whereas V. parvula and V. denticariosi were not isolated at all. These characteristics of the distribution and frequency of Veillonella species are similar to those reported in previous studies. Although further studies are needed in other countries, in this study, a successful novel one-step PCR method was established to detect Veillonella species in human oral cavities easily and effectively. Furthermore, this is the first report investigating the distribution and frequency of Veillonella species in tongue biofilms of Thai children.

Efficacy of xylitol and fluoride mouthrinses on salivary Mutans streptococci.

OBJECTIVE To evaluate the level of salivary Mutans streptococci (MS) after rinsing with xylitol, fluoride, and a combination of xylitol and fluoride solutions, compared with distilled water. METHODS Eighty healthy 8-9 years old subjects with high level of MS (> 10(5) CFU/mL) were equally divided into 4 groups. Subjects rinsed their mouths for 1 min with 10 mL of 0.05% (w/v) sodium fluoride (NaF), 12.5% (w/v) xylitol or 0.05% (w/v) NaF + 12.5% (w/v) xylitol 3 times daily over 10 weeks. Distilled water rinsed group served as a control. Paraffin-stimulated whole saliva samples were collected at baseline, 5 weeks, and 10 weeks after rinsing to determine the level of salivary MS by culturing on Mitis Salivarius Bacitracin agar. The statistical significance was calculated by Kruskal Wallis, Mann Whitney U, and Wilcoxon signed-rank tests at a significant level of P< 0.05. RESULTS Significant reductions in MS count were observed in subjects using 0.05% NaF + 12.5% xylitol over other groups within 5 weeks and after 10 weeks and 12.5% xylitol alone after 10 weeks compared with baseline. CONCLUSIONS The present study provides evidence for the inhibitory effect of xylitol, used in combination with fluoride, delivered in the form of mouthrinse, on salivary MS in the group of schoolchildren.

Exploring the salivary microbiome of children stratified by the oral hygiene index

Poor oral hygiene often leads to chronic diseases such as periodontitis and dental caries resulting in substantial economic costs and diminished quality of life in not only adults but also in children. In this study, the salivary microbiome was characterized in a group of children stratified by the Simplified Oral Hygiene Index (OHI-S). Illumina MiSeq high-throughput sequencing based on the 16S rRNA was utilized to analyze 90 salivary samples (24 Good, 31 Moderate and 35 Poor oral hygiene) from a cohort of Thai children. A total of 38,521 OTUs (Operational Taxonomic Units) with a 97% similarity were characterized in all of the salivary samples. Twenty taxonomic groups (Seventeen genera, two families and one class; Streptococcus, Veillonella, Gemellaceae, Prevotella, Rothia, Porphyromonas, Granulicatella, Actinomyces, TM-7-3, Leptotrichia, Haemophilus, Selenomonas, Neisseria, Megasphaera, Capnocytophaga, Oribacterium, Abiotrophia, Lachnospiraceae, Peptostreptococcus, and Atopobium) were found in all subjects and constituted 94.5–96.5% of the microbiome. Of these twenty genera, the proportion of Streptococcus decreased while Veillonella increased with poor oral hygiene status (P < 0.05). Furthermore, an unassigned species of Veillonella, Veillonella dispar and Veillonella parvula tended to be elevated in the Poor oral hygiene group. This is the first study demonstrating an important association between increase of Veillonella and poor oral hygiene status in children. However, further studies are required to identify the majority of Veillonella at species level in salivary microbiome of the Poor oral hygiene group.

Application of surface plasmon resonance biosensor for the detection of Candida albicans

In this study, surface plasmon resonance imaging (SPR imaging) was developed for the detection of Candida albicans which is a causal agent of oral infection. The detection was based on the sandwich assay. The capture antibody was covalently immobilized on the mixed self assemble monolayers (SAMs). The ratio of mixed SAMs between 11-mercaptoundecanoic acid and 3-mercaptopropanol was varied to find the optimal ratio for use as a sensor surface. The results showed that the suitable surface for C. albicans detection was SAM of carboxylic (mixed SAMs ), even though mixed SAMs had a high detection signal in comparison to mixed SAMs , but the non-specific signal was higher. The detection limit was 107 cells/ml for direct detection, and was increased to 106 cells/ml with sandwich antibody. The use of polyclonal C. albicans antibody as capture and sandwich antibody showed good selectivity against the relevant oral bacteria including Escherichia coli, Streptococcus mutan, Staphylococcus aureus, β-streptococci, and Lactobacillus casei. SPR platform in this study could detect C. albicans from the mixed microbial suspension without requirement of skillful technician. This SPR imaging biosensor could be applied for Candida identification after cultivation.