Effects of various surface treatments on the bonding efficacy of noncarious cervical sclerotic lesions / 华西口腔医学杂志

Noncarious cervical sclerotic lesions (NCSL) are dental cervical lesions with noncarious sclerotic dentine (NCSD), which appears smooth, hard, and either light yellow or dark brown. Most NCSLs are wedge or dish shaped and commonly occur in canines and premolars, leading to dental hypersensitivity and aesthetic defect. The principal treatment is composite resin restoration; however, many clinical problems, such as retention loss, should not be ignored. NCSL's bonding interface includes NCSD and enamel, and interface pre-treatment can promote the bonding effect. This review summarizes current surface treatment methods and their influence on the bonding effectiveness of NCSL to provide guidance for clinical practice.

Effect of zoladronate on the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells / 华西口腔医学杂志

OBJECTIVE@#To evaluate the effect of zoledronate acid (ZA) on the proliferation and osteogenic differentiation of rat mesenchymal stem cells (BMSCs).@*METHODS@#The BMSCs isolated from the SD rats were cultured with different concentrations of ZA (1, 5, 10, and 20 μmol·L), and the contro1 group received the same volume of culture medium but without ZA. Cell counting kit-8 was used to detect proliferation activity in each group. Alkaline phosphatase (ALP) staining and alizarin red staining were used to detect the osteogenic differentiation ability in each group. The gene expression levels of ALP, bone morphogenetic protein-2 (BMP-2), typeⅠcollagenase (COL-Ⅰ), runt-related transcription factor-2 (Runx-2), zinc finger structure transcription factor (Osx), osteocalcin (OCN), and osteopontin (OPN) were evaluated by real-time quantitative polymerase chain reaction (qRT-PCR).@*RESULTS@#Zoledronate at 1 μmol·L⁻¹ concentration had no effect on the proliferation and osteogenic differentiation of BMSCs. No significant difference was observed between this group and the control group (P>0.05). When the ZA concentration was more than 1 μmol·L⁻¹, ZA inhibited the proliferation and osteogenic differentiation of BMSCs, and the effect was concentration dependent. The difference between each group and the control group was statistically significant (P<0.05). At ZA concentration of 5 μmol·L⁻¹, ZA enhanced the expression of ALP, BMP-2, COL-Ⅰ, Runx-2, Osx, OCN, and OPN (P<0.05). However, at ZA concentration of more than 5 μmol·L⁻¹, the expression levels of osteogenicrelated genes in each group was lower than those of the control group (P<0.05).@*CONCLUSIONS@#Low ZA concentration has no effect on the proliferation and osteogenic differentiation of BMSCs. ZA at 5 μmol·L⁻¹ concentration inhibits the proliferation but promotes the osteogenic differentiation of BMSCs. High ZA concentration inhibits the proliferation and osteogenic differentiation of BMSCs.

Human mycobiome and diseases / 华西口腔医学杂志

The proportion of mycobiome is less than 1% of human microbiome. However, fungal community plays a key role in human health and diseases. With high-throughput sequencing applications, the structure and composition of mycobiome in the mouth, lung, gut, vagina, and skin have been analyzed, and the role of microbiome in diseases has been investigated. Mycobiome also influences the composition of bacteriome and includes key species that maintain the structure and function of microbial communities. Fungi also influence host immune responses. In this review, we summarized the mycobiome com-position at various sites and different diseases and the interactions between fungi-bacteria and fungi-host.

Recent advances in direct pulp capping materials / 华西口腔医学杂志

The long-term effect of direct pulp capping and pulpotomy is closely related to the type of pulp capping materials. Various kinds of direct pulp capping materials are available, such as calcium hydroxide and mineral trioxide aggregates. Diverse new pulp capping materials have been reported recently. The excellent performance of calcium silicates has attracted much attention in previous studies. Moreover, enamel matrix derivative (Emdogain), which is capable of regeneration and remineralization, and other materials with similar capabilities have shown potential for use in pulp capping.

Effects of 45S5 bioglass on surface properties of dental enamel subjected to 35% hydrogen peroxide / 国际口腔科学杂志·英文版

Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.

Chemical composition of Galla chinensis extract and the effect of its main component(s) on the prevention of enamel demineralization in vitro / 国际口腔科学杂志·英文版

To determine the chemical composition of Galla chinensis extract (GCE) by several analysis techniques and to compare the efficacy of GCE and its main component(s) in inhibition of enamel demineralization, for the development of future anticaries agents, main organic composition of GCE was qualitatively determined by liquid chromatography-time of flight-mass spectrometry (LC-TOF-MS) and quantified by high-performance liquid chromatography-diode array detector (HPLC-DAD). Inorganic ions were tested by inductively coupled plasma-atomic emission spectroscopy and F was especially measured by ion chromatography. Then, bovine enamel blocks were randomly divided into four treatment groups and were subjected to a pH-cycling regime for 12 times. Each cycle included 5-min applications with one of four treatments: 4 g⋅L(-1) GCE solution, 4 g⋅L(-1) gallic acid (GA) solution, 1 g⋅L(-1) NaF solution (positive control), deionized water (DDW, negative control), and then 60-min application in pH 5.0 acidic buffer and 5-min application in neutral buffer. Acidic buffers were retained for calcium analysis. The main organic composition of GCE were GA and its isomer, and, to a lesser extent, small molecule gallotannins. The content of GA in GCE was 71.3%±0.2% (w/w). Inorganic ions were present in various amounts, of which Ca was (136±2.82) µg⋅g(-1), and Zn was (6.8±0.1) µg⋅g(-1). No F was detected in GCE. In pH cycling, GA showed an effect similar to GCE in inhibiting enamel demineralization (P>0.05). GA was found to be the main effective, demineralization inhibiting component of GCE and could be a promising agent for the development of anticaries agents.

Comparison of the enhanced remineralization of initial enamel carious lesions treated with original and neutral Galla chinensis in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To compare the effect of original and neutral Galla chinensis in promoting the remineralization of initial enamel carious lesions in vitro and to investigate the influence of Galla chinensis with different pH on the promoting effect.</p><p><b>METHODS</b>Bovine sound enamel slabs were demineralized to produce initial carious lesion in vitro. Then the lesions were exposed to a pH-cycling regime for 12 days. Each daily cycle included 4 × 1 min application of one of four treatments: distilled and deionized water (DDW), aqueous solutions of NaF, acidic or neutral aqueous solutions of Galla chinensis extract (GCE). Before and after pH-cycling, the surface topography of the enamel slabs was observed by atomic force microscopy (AFM), and the integrated mineral loss and lesion depth of all the specimens were analysed by transverse microradiography.</p><p><b>RESULTS</b>AFM images revealed the surface topographical changes of GCE-treated enamel. The percentage change of integrated mineral loss (ΔIML%) of the samples of NaF group, DDW group, pH 3.8 GCE group and pH 7.0 GCE group was (-38 ± 14)%, (+43 ± 7)%, (-10 ± 4)% and (-11 ± 4)% respectively. The percentage of lesion depth (ΔLD%) of the samples of NaF group, DDW group, pH 3.8 GCE group and pH 7.0 GCE group was (-27.79 ± 3.51)%, (+21.13 ± 2.83)%, (-8.43 ± 3.32)% and (-9.20 ± 3.89)% respectively. There was no significant difference in ΔIML% and ΔLD% between pH 3.8 and pH 7.0 GCE-treated enamel.</p><p><b>CONCLUSIONS</b>There is no significant difference in enhancement of remineralization of initial enamel carious lesions between the original and neutral Galla chinensis. Different pH Galla chinensis does not have obvious influence on remineralization. It is unnecessary to regulate the pH value of queous solution of Galla chinensis extract which acts as a anti-caries agent.</p>

Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling / 国际口腔科学杂志·英文版

Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as "bait": Fusobacterium nucleatum (F. nucleatum) whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans (S. mutans) whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the "bait" oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The "prey" bacterial mixtures (including known species or natural saliva samples) were added, unbound cells were washed off after the incubation period and the remaining cells were eluted using 0.2 mol x L(-1) glycine. Genomic DNA was extracted, subjected to 16S rRNA PCR amplification and separation of the resulting PCR products by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F. nucleatum adhered to a variety of bacterial species including uncultivable and uncharacterized ones. This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species.

Analysis of relationship between the detection of Enterococcus faecalis in post-treatment endodontic disease and clinical symptom or sign / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To detect the Enterococcus faecalis (E. faecalis) in post-treatment endodontic disease, and to analyze the relationship between the occurrence of E. faecalis and clinical symptom.</p><p><b>METHODS</b>108 teeth which need root canal retreatment were collected, and the clinical symptoms and physical signs were recorded. Bacterium samples from root canal were taken, and genome DNA from bacterial samples were extracted. The occurrence of E. faecalis by means of the polymerase chain reaction was investigated.</p><p><b>RESULTS</b>The detection rate of E. faecalis in cases of root canal retreatment was 47.2%, while in cases with symptoms or signs, or cases with both symptoms and signs, the root canal E. faecalis detection rates were 52.6%, 57.9%, 62.5%. The detection rates of E. faecalis between cases with clinical symptom and without clinical symptom demonstrated statistical significance (P < 0.05). The detection rates between cases with both clinical symptom and manifestly aneretic root and cases without clinical symptom and manifestly aneretic root had statistical significance (P < 0.05). In the group of clinical symptom, the detection rate of E. faecalis in cases with biting pain was 66.7%, clearly higher than those without biting pain (P < 0.05).</p><p><b>CONCLUSION</b>The occurrence of E. faecalis in cases of root canal retreatment correlates with clinical symptoms.</p>

Effects of different sterilization methods on mechanical properties of dental fissure bureffects of different sterilization methods on mechanical properties of dental fissure bur / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose was to analyze the effects of three sterilization methods (dry heat sterilization, steam sterilization, and chemical sterilization) on the corrosion of dental fissure bur.</p><p><b>METHODS</b>200 dental fissure burs were distributed to 10 groups. Bending strength, elastic modulus, and torsional strength were measured by bending and torsional instrument and calculated with special designed software. Among the three sterilization methods, the steam sterilization group showed the most evident.</p><p><b>RESULTS</b>The corrosion was most severe in steam sterilization group, followed by chemical sterilization, dry heat sterilization. With the sterilization time increased, bending strength, elastic modulus, and torsional strength decreased respectively. Of the three sterilization methods, the mechanical properties were decreased most evidently by steam sterilization, followed by chemical sterilization and dry heat sterilization.</p><p><b>CONCLUSION</b>It is proved that the bending strength, elastic modulus and torsional strength have a tight relationship with the corrosion of dental fissure burs. The corrosion was most severe in steam sterilization group, followed by chemical sterilization, dry heat sterilization. In regards of the corrosive effect, the dry heat sterilization might be the best way to sterilize the dental fissure burs.</p>

Usage status of periapical films undertaking in root canal treatment / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To determine the current radiographic practices of root canal treatment (RCT) undertaken by endodontists, general dentist practitioners (GDPs) and interns, and to analyze the relationship between the usage of periapical films and the quality of RCT.</p><p><b>METHODS</b>The patients who had received RCT treatment in West China College of Stomatology were investigated at random and were divided into three groups: Endodontists treating group, GDPs treating group and interns treating group according treating physician. The usage status of periapical film were investigated by the well designed questionnaires. The obturation quality of postoperative films were evaluated. Chi-square analysis was used to compare usage rates of periapical films of three groups. Mann-Whitney test was used to determine the relationship between the usage of periapical films and the quality of RCT.</p><p><b>RESULTS</b>571 teeth of 412 patients were investigated. In endodontists treating group, GDPs treating group and interns treating group, the usage rates of preoperative films were 95.3%, 89.5% and 92.1% respectively. The usage rates of working length films were 5.2%, 1.1% and 5.8% respectively. The usage of master point films was 94.8%, 72.1% and 97.4% respectively. The usage of postoperative films was 97.9%, 76.3% and 95.3% respectively. There were statistically significant differences among the working length films, master point films and postoperative films of three groups (P<0.05). The periapical films of adequate quality RCT and inadequate quality RCT were 3.14+/-0.639 and 2.84+/-0.736 respectively. There was statistically significant difference between periapical films of adequate quality RCT and inadequate quality RCT (P<0.05).</p><p><b>CONCLUSION</b>Radiographic practices of endodontists and interns are more standardized than GDPs. Quality RCT is related to radiographic practices. Standard radiographic practices would be benefit to RCT.</p>

Determination of organic acids in dental plaque with high performance liquid chromatography / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish determination method of formic acid, lactic acid, acetic acid and succinic acid in dental plaque with high performance liquid chromatography (HPLC).</p><p><b>METHODS</b>After the samples were centrifuged, 2 microL supernatant was transferred to a 1 mL centrifuge tube and diluted in water, then was determined with HPLC. The mixture of phosphate buffer and methanol (97:3) as mobile phase throughout the experiment. The determination of organic acid was performed on Phenomenex C18 column and at their maximum absorption wave.</p><p><b>RESULTS</b>The linear ranges of formic acid, lactic acid, acetic acid and succinic acid were 0.110-500, 0.049-500, 0.047-500, 0.084-500 microg/mL. The detection limits were 0.110, 0.049, 0.047, 0.084 microg/mL. The relative standard derivation were 9.5%, 7.9%, 4.3%, 4.2%. The average recoveries of samples were 82%-112%, 82%-102.5%, 90%-115%, 80%-110%.</p><p><b>CONCLUSION</b>The method was simple, quick and adapt for analysis of organic acid in dental plaque.</p>

Initial study on the discrimination of oral microorganisms with a metabonomics method / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish the spectra of metabolites that coued be employed in identification of oral pathogenic bacteria, and try to find a convenient and rapid way to discriminate oral microorganisms.</p><p><b>METHODS</b>Suspensions of Streptococcus mutans ATCC 25175, Streptococcus sanguis ATCC 10556 and Lactobacillus acidophilus ATCC 4356 with same density were preparecd and cultured respectively at improved TPY liquid culture medium. The growth quantity were measured periodically by a turbidimeter. And the growth curves of the inoculated bacteria were completed. The culture solutions in stationary phase of the three bacteria were tested with 1H-nuclear magnetic resonance (1H-NMR) spectroscopy respectively. The data of 1H-NMR spectroscopy results were analyzed by principal components analysis (PCA).</p><p><b>RESULTS</b>The PCA showed the obvious clustering phenomena and the points of three group differentially centralized to three clusters. Therefore, the NMR-based metabonomics profiles could discriminate the three different kinds of bacteria.</p><p><b>CONCLUSION</b>The metabonomics is a promising new technology for developing to a rapid discrimination method of oral pathogenic bacteria.</p>

Effects of traditional Chinese medicine on oral bacteria biofilm / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of compounds of Galla chinensis extract (GCE) and Nidus vespae extract-1 (WVE1) on oral bacteria biofilm structure and activity and to determine the possibility of caries prevention by the compounds.</p><p><b>METHODS</b>The morphology and activity of treated-oral bacterial biofilm and untreated-oral bacterial biofilm were observed by using fluorescence microscope in combination of idio-fluorochrome to label the died and living bacteria. The visible light semiquantitative method was used to measure biomass glucosyltransferase (GTF, A620) values and to determine the effects of active compounds of GCE and NVE1 on GTF of oral bacteria biofilm.</p><p><b>RESULTS</b>The living bacteria in the untreated 24 h bacterial biofilm was dominant, and only a small number of died bacteria were found, the biofilm structure was regular and clear. GCE, GCE-B and NVE1 could inhibit the bacteria in the dental biofilm, which showed significant difference with the negative control. GCE and NVE1 could also inhibit GTF activity of 24 h bacterial biofilm in comparison with the negative control.</p><p><b>CONCLUSIONS</b>The traditional Chinese medicine Galla chinensis and Nidus vespae could not only inhibit bacteria growth on oral bacterial biofilm, but also function by adjusting biofilm structure, composition and GTF activity of 24 h bacterial biofilm.</p>

Effect of Galla Chinesis on the demineralization of dental root tissue in pH cycling model / 中国中药杂志

<p><b>OBJECTIVE</b>To evaluate the anti-demineralization efficacy of Galla Chinesis in pH cycling model for elucidating the anti-root caries mechanism.</p><p><b>METHOD</b>Anti-demineralization efficacy evaluation of the natural medicine in the pH-cycling models was used . Sound human root blocks were pH-cycled through the treatment solution, acidic buffer and neutral buffer. The cycling times for demineralization study were 12 times, 2 times per day. The acidic buffers were retained for calcium analysis by atomic adsorption spectroscopy. The sections of blocks were analysed after pH-cycling by CLSM. Treatments were 4 g x L(-1). Galla Chinesis, 1 g x L(-1) NaF solution and distilled water.</p><p><b>RESULT</b>Galla Chinesis was found to inhibit the demineralization in the pH cycling model. Although the effect was not as good as fluoride, there was no significant difference between the two groups.</p><p><b>CONCLUSION</b>These data suggest that Galla Chinesis could modulate the mineralisation behaviour of root tissue in a defined chemical circumstance. These findings support the proposition that Galla Chinesis may be a promising anticaries natural medicine in the future.</p>

Study of the relationship between oral Actinomyces and childhood caries / 华西口腔医学杂志

<p><b>OBJECTIVE</b>Actinomyces are members of the indigenous oral microbiota which have been implicated in root caries, but their role in childhood caries initiation and progression is not well-understood. The distribution of Actinomyces in supragingival plaque on the primary teeth and the relationship between oral Actinomyces spp. and childhood caries primarily were investigated.</p><p><b>METHODS</b>Forty children aged from three to five years old were divided into two groups. Twenty children were caries-free and twenty were caries-susceptible. Dental plaque samples from different places of the teeth were collected with sterile toothpick and polymerase chain reaction was performed with specific primers which were designed for this research.</p><p><b>RESULTS</b>Actinomyces spp. were detected 100% in the caries-free group, while 95% in the caries-susceptible group. There was no significant differences between the two groups (P > 0.05). Actinomyces naeslundii, Actinomyces odontolyticus, Actinomyces gerencseriae, Actinomyces israelii and Actinomyces viscosus all could be detected in both groups. The prevalence of Actinomyces naeslundii, Actinomyces gerencseriae and Actinomyces odontolyticus were higher in caries-free group than those in caries-susceptible group (P < 0.05), while the prevalence of Actinomyces israelii and Actinomyces viscosus had no significant difference between the two groups (P > 0.05).</p><p><b>CONCLUSION</b>Actinomyces is the main colonized bacteria in the supragingival plaque of children. The prevalence of the Actinomyces spp. may have a negative relationship with the childhood caries, and has nothing to do with different places of the teeth.</p>

Initial study on discrimination of oral microorganisms with the metabonomics technique / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility of employing metabonomics method in identification of oral pathogenic bacteria.</p><p><b>METHODS</b>The Streptococcus mutans ATCC25175 and Actinomyces viscosus ATCC15987 were respectively inoculated in same certain culture medium. The growth curves of the inoculated bacteria were drown by turbidimetry. The culture solutions in four different growth phases of the both bacteria were used to test with the 1H-Nuclear magnetic resonance (1H-NMR) spectroscopy respectively. The data of 1H-NMR spectroscopy results were analyzed by principal components analysis (PCA).</p><p><b>RESULTS</b>The PCA showed the obvious clustering phenomena and the points of two group data stayed differentially together by two clusters. Therefore, the NMR-based metabonomics profiles can discriminate the two different kind of bacteria.</p><p><b>CONCLUSION</b>The metabonomics can be expected to be a kind of promising useful method in quick discrimination of oral pathogenic bacteria.</p>

Study of susceptibility of oral bacteria biofilm to traditional Chinese drug preventing caries / 华西口腔医学杂志

<p><b>OBJECTIVE</b>Using MBEC-Assay to assay minimal biofilm eradication concentration (MBEC) of Galla Chinensis and Nidus Vespae to oral bacterial biofilm. To set up traditional Chinese medicine susceptibility pharmacodynamic empirical study methods of oral bacterial biofilm.</p><p><b>METHODS</b>Cariogenic bacteria strains were selected (Streptococcus mutans ATCC 25175, Streptococcus sanguis ATCC 10556, Lactobacillus rhamnosus AC 413, Actinomyces naeslundii WVU 627) in this study. Extraction components of Galla Chinensis were GCE (aqueous extract), GCE-B (30% alcohol extract) and extraction components of Nidus Vespae were NVE1 (95% alcohol extract). (1) To observe oral bacterial biofilm formatiom in MBEC-Device at different time. (2) MBEC-HTP-Assay: The minimal inhibitory concentration (MIC) and minimal biofilm eradication concentration (MBEC) of GCE, GCE-B and NVE1 to oral bacteria strains were determined.</p><p><b>RESULTS</b>Oral bacterial biofilm were readily formed on the lid of MBEC-Device under selected condition (observed by SEM). Oral cariogenic bacteria growing as plankton populations were sensitive to GCE, GCE-B and NVE1. To GCE, GCE-B and NVE1, oral cariogenic bacterial biofilm were 2-16 times less susceptible than growing plankton bacteria. GCE and GCE-B were the most effective medicine against oral cariogenic bacterial biofilm. NVE1 were effective in killing oral-bacterial biofilm at relatively high concentration.</p><p><b>CONCLUSION</b>GCE and GCE-B were effective medicine against oral cariogenic bacterial biofilm. MBEC (minimal biofilm eradication concentration) can provide a relative accurate medicine concentration for clinical test.</p>

Correlation of oral Candida spp. and denture-wearing in healthy elderly / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the frequency and intensity of Candida spp. incidence from the oral cavities of the healthy elderly in Chengdu, and to study the role of the dentures in the distribution of oral Candida spp.</p><p><b>METHODS</b>A total of 212 individuals(age > 60 years) were divided into four groups: A1 (48 man with dentures), B1 (61 man without dentures), A2 (53 women with dentures) and B2 (50 women without dentures). Samples of their oral flora were obtained by rinsing with 10 mL PBS solution. The samples were centrifuged and resuspended in PBS (500 microL), and plated onto Sabouraud's dextrose agar. CHROMagar Candida, sugar assimilation patterns (API 20C AUX tests) were used to determine Candida spp. The total number of yeast colonies on the plates was considered as the relative intensity of oral Candida.</p><p><b>RESULTS</b>Candida spp. was isolated from 116 healthy elderly individuals (54.72%), such as C. albicans, C. parapsilosis, C. krusei, C. guilliermondii, C. tropicalis, etc. The frequency of Candida spp. in A1, B1, A2 and B2 was 66.67%, 36.07%, 64.15%, and 56.00%, respectively. The frequency of C. albicans in A1, B1, A2 and B2 was 56.25%, 21.31%, 56.60% and 38.00%, respectively. The frequency of Candida spp. and the intensity of Candida spp. were greater for individuals in the denture-wearing group than that in the control.</p><p><b>CONCLUSION</b>The frequency and intensity of Candida spp. incidence from the healthy elderly are closely correlated with denture-wearing, and the differences of the frequency and intensity of Candida spp. incidence in the elderly are due to the differences of frequency and intensity of C. albicans incidence.</p>

Effect of chemical compounds of Galla chinensis on enamel surface rehardening in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of chemical compounds extracted from Galla chinensis on enamel surface rehardening in vitro.</p><p><b>METHODS</b>Sixty bovine enamel blocks with early carious lesions were randomly divided into six groups: group1 treated NaF (positive control); group2 with GCE; group3 with GCE-B; group4 with GCE-B1; group5 with GCE-B2 and group6 with deionized water (negative control). The lesions were subjected to a pH-cycling regime for 12 days. Surface enamel microhardness was measured on the enamel blocks before and after demineralization. After pH-cycling, and the percentage of surface microhardness recovery (SMHR) was calculated.</p><p><b>RESULTS</b>Obvious increase of the surface hardness of the enamel was observed in all the treatments except GCE-B2 and deionized water (P < 0.05).</p><p><b>CONCLUSIONS</b>The present study demonstrates the potential of the three GCEs (GCE, GCE-B and GCE-B1) to effect net rehardening of artificial carious lesions under dynamic pH-cyclic conditions.</p>