<Emphasis Type="Italic">Tannerella forsythia</Emphasis> and the <Emphasis Type="Italic">HLA-DQB1</Emphasis> allele are associated with susceptibility to periodontal disease in Japanese adolescents

Periodontal disease is a multiple factor disease caused by genetic factors, environmental factors, and periodontal bacteria (periodontal pathogens). The present study aimed to elucidate the risk factors for periodontal disease in Japanese adolescents. Subjects (11–16 years old) were classified into three groups: localized aggressive periodontitis (LAP), periodontal attachment loss (PAL), and periodontally healthy (PH) groups. Genomic DNA isolated from the buccal mucosa was used for single-nucleotide polymorphism analyses of the candidate genes (interleukin-1α-889; interleukin-1α +4845; interleukin-1β +3954; an immunoglobulin G Fc gamma receptor, FcγRIIa-R/H131; and a human leukocyte antigen class II allele, HLA-DQB1) of aggressive periodontitis. Subgingival plaque samples obtained from the same subjects were used for 16S rRNAbased polymerase chain reaction analysis of five important periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, and Tannerella forsythia). Tannerella forsythia was detected in the deepest periodontal pockets in all subjects in the LAP and PAL groups. The prevalence of an atypical BamHI restriction site in HLA-DQB1 of the LAP group was significantly higher than that in the PH and PAL groups. Furthermore, all subjects who had the atypical BamHI restriction site in HLA-DQB1 had T. forsythia infection. These results suggested that T. forsythia is associated with periodontal disease in Japanese adolescents and also suggested that HLA-DQB1 is related to LAP and is associated with T. forsythia infection.     

Adhesion of<Emphasis Type="Italic"> Porphyromonas gingivalis</Emphasis> to cultured pocket epithelium: mono- and multi-layered

Adhesion of bacteria to epithelial cells might be influenced by the degree of cell differentiation, as observed in the multi-layering process of epithelial cells. In the present study, the adhesion of a large group of clinical Porphyromonas gingivalis strains (n=11) to in vitro cultured mono- and multi-layers of epithelial cells was examined and compared. The tissue samples originated from 6 patients with chronic adult periodontitis. Porphyromonas gingivalis bacteria adhered more to mono-layers as opposed to the more differentiated multi-layers. Differences between the clinical P. gingivalis strains, however, became obvious only on multi-layers. These partially differentiated cells may also better represent the individual subject variations. Mono-layer cultures, which are simpler to obtain, seem to be less precise. The importance of cell differentiation on bacterial adhesion needs more attention.     

Effects of low-concentrated chlorhexidine on growth of<Emphasis Type="Italic"> Streptococcus sobrinus</Emphasis> and primary human gingival fibroblasts

The aim of this study was to investigate the in vitro effects of low concentrations of chlorhexidine (CHX) on the proliferation of Streptococcus sobrinus (ATCC 33478) and primary human gingival fibroblasts (HGF). Liquid cultures of bacteria or human gingival fibroblasts were exposed to CHX concentrations ranging from 0.07 to 40 M in microtiter plates at 37°C for 24 h. Bacteria or cells grown without CHX served as controls. The effects of CHX were determined either by measurements of the optical density (OD) of bacterial cultures or by evaluation of cell growth with the DNA-intercalating fluorescent stain H33342 in comparison to untreated controls. Results were evaluated calculating means and standard deviations. Data were statistically analyzed by an ANOVA using Post Hoc tests (p<0.005). No growth inhibition of S. sobrinus was found at concentrations between 0.07 and 0.15 M CHX, whereas 0.3 M CHX led to an elongated (2 h more) lag phase and 0.6 M CHX induced a lag phase of 4 h more and a minor inclination of the curve in the log phase. Concentrations of CHX1.25 M completely inhibited growth of S. sobrinus. On the contrary, CHX showed no significant effect on growth of HGF at concentrations 5 M. A slight growth inhibition was only observed at a concentration of 5 M. CHX-concentrations of 10 and 20 M reduced cell growth to 88 or 75% of control assays. Data analysis showed that overall treatment effects were highly significant (p<0.005). Our data reveal that chlorhexidine inhibits proliferation of S. sobrinus even at very low concentrations while concentrations of CHX5 M are not cytotoxic to human gingival fibroblasts.     

PCR detection of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> and <Emphasis Type="Italic">Aggregatibacter actinomycetemcomitans</Emphasis> in dental plaque samples from Haitian adolescents

Streptococcus mutans and Aggregatibacter actinomycetemcomitans are oral pathogens associated with dental caries and periodontitis, respectively. The aim of this study was to determine the colonization of these two microorganisms in the dental plaque of a group of Haitian adolescents using two different polymerase chain reaction (PCR) methods, standard PCR, and quantitative real-time PCR (qPCR) assays. Fifty-four pooled supra-gingival plaque samples and 98 pooled sub-gingival plaque samples were obtained from 104 12- to19-year-old rural-dwelling Haitians. The total genomic DNA of bacteria was isolated from these samples, and all participants also received caries and periodontal examinations. Caries prevalence was 42.2%, and the mean decayed, missing, and filled surface (DMFS) was 2.67 ± 5.3. More than half of the adolescents (53.3%) experienced periodontal pockets (Community Periodontal Index score ≥3). S. mutans was detected in 67.3% by qPCR and 38.8% by PCR of the supra-gingival plaque samples (p < 0.01), and 36.6% by qPCR and 8.1% by PCR of the sub-gingival samples (p < 0.01). A. actinomycetemcomitans was detected in 85.1% by qPCR and 44.0% by PCR of the sub-gingival samples (p < 0.01), but the prevalence was similar, 67.3% by qPCR and 59.2% by PCR, in the supra-gingival plaque samples. Neither age nor gender was significantly correlated to the bacterial colonization. The results demonstrated a moderate-to-high prevalence of S. mutans and A. actinomycetemcomitans in the Haitian adolescent population, and qPCR is more sensitive than standard PCR in field conditions. These findings suggest that qPCR should be considered for field oral epidemiologic studies and may be necessary in investigations having major logistic challenges.     

Effect of mouthrinses on <Emphasis Type="Italic">Aggregatibacter actinomycetemcomitans</Emphasis> biofilms in a hydrodynamic model

The aim of the study was to evaluate the effects of Listerine®, Meridol®, and Perioaid® on the viability and total number of bacteria in established biofilms using an in vitro model under hydrodynamic conditions. Biofilms of Aggregatibacter actinomycetemcomitans were placed in a modified Robbins device and rinsed twice daily during 4 days. Bacteria were quantified by culture and quantitative polymerase chain reaction. Visualization of the samples was performed by scanning electron and confocal laser scanning microscopy, combined with a fluorescent vital staining. All three mouthrinses caused a significant reduction in the number of cultivable A. actinomycetemcomitans in a biofilm. Perioaid® was significantly the most powerful in killing the biofilm-protected bacteria and also in counteracting the development of thick dense microbial communities. The total amount of bacteria was not significantly affected by Listerine® and Meridol®.     

Antifungal susceptibility of <Emphasis Type="Italic">Candida albicans</Emphasis> biofilms on titanium discs with different surface roughness

Although it is well known that fungal biofilms have increased resistance to antimicrobial agents, limited information is available on the formation of candidal biofilms on implant surfaces with different surface roughness and their resistance to conventional antifungal therapy. In the current study, the effect of increasing the surface roughness of titanium discs on the susceptibility of Candida albicans biofilms to amphotericin B was determined. Grade I commercially pure titanium discs were sandblasted with 99.6% aluminium oxide of different grit sizes, producing surface roughness of 0.90, 1.88 and 3.82 μm (Groups A, B and C), respectively (P < 0.001). The antifungal susceptibility of C. albicans biofilm grown on different Ti discs was determined using XTT assay. The 50% reduction in metabolic activity (50% RMA) of planktonic C. albicans (0.5 μg/mL) was much lower than those from Groups A, B and C (2, 16, 2 μg/mL, respectively), while the 50% RMA from Group B was three-fold higher than those from Groups A and C. In conclusion, difference in titanium surface roughness was associated with variations in the antifungal resistance of the candidal biofilm. Group C appeared to have an optimum surface roughness for biofilm resistance.     

Comparison of different methods to detect <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in the dental plaque of dyspeptic patients

The aim of this study was to compare different methods of detection of Helicobacter pylori (H. pylori) in the dental plaque of dyspeptic patients. After recording the clinical indices, culture and polymerase chain reaction (PCR) methods were performed on plaque samples, while rapid urease test in addition to these tests was carried on gastric samples from 67 dyspeptic patients who attended for an upper gastrointestinal endoscopy. Forty-seven of 67 patients were H. pylori-positive in gastric biopsy material whereas the microbial dental plaque from 19 patients demonstrated H. pylori positivity detected by PCR. Among the patients, 25.4% harbored H. pylori both in the stomach and in microbial dental plaque. No significant correlations were found among the presence of H. pylori in the stomach, in plaque, and clinical variables (P > 0.05). Although oral hygiene was observed optimal and the mean of pocket depth was not found to be higher, the prevalence of H. pylori was observed to be higher in dental plaque. According to our results, PCR technique gave the highest detection rate both in gastric biopsy and in dental plaque compared to the other methods used.     

Adherence of <Emphasis Type="Italic">Candida albicans</Emphasis> to denture base acrylics and silicone-based resilient liner materials with different surface finishes

This study evaluated the surface roughness and Candida albicans adherence on denture base acrylic resins and silicone-based resilient liners with different surface finishes. Four commercial denture base acrylic resins (three heat polymerized and one room temperature polymerized) and five silicone-based liner materials (two heat polymerized and three room temperature polymerized) (10 × 10 × 2 mm) were tested in this study. The materials were processed against glass or plaster or finished with a tungsten carbide bur. Surface roughness measurements were made using a profilometer with an optical scanner probe. All specimens were ultrasonically cleaned in water for 15 s, autoclave sterilized, and contaminated with C. albicans solution for adherence assay evaluation. The materials processed against the glass surface showed significantly lower surface roughness values (0.11 ± 0.1–1.66 ± 1.1 μm) than those of the materials processed against the dental plaster (2.61 ± 0.2–6.12 ± 2.8 μm) or roughening with a bur (1.48 ± 0.2–7.05 ± 1.2 μm; p < 0.05, one- or two-way analysis of variance). Also, the materials processed against the glass surface showed lower C. albicans adhesion (mean ranks 120.36) than those of the materials processed against the dental plaster (mean ranks 139.77) or roughening with a bur (mean ranks 143.06), but the differences were not statistically significant (p > 0.05, Kruskal–Wallis and Mann–Whitney). In all types of surface finishes, C. albicans adhesion on denture base acrylics was significantly less (mean ranks 90.18–90.40) than those of silicone liners (mean ranks 119.38–205.18; p < 0.01, Kruskal–Wallis).     

Impact of <Emphasis Type="Italic">Streptococcus mutans</Emphasis> on the generation of fluorescence from artificially induced enamel and dentin carious lesions in vitro

The purpose of this study was to examine whether Streptococcus mutans is implicated in the generation of fluorescence detected in carious lesions. Enamel surfaces and dentin cavities of extracted human teeth were subjected to artificial caries generation by exposing them either to a culture medium containing S. mutans or to a lactic acid buffer for 2 weeks. Fluorescence from the lesions was detected with confocal laser scanning microscopy or fluorescence microscopy at various excitation wavelengths, and maximum fluorescence radiance was computed using imageanalyzing software. Culture media of S. mutans were also examined for fluorescence generation. The results demonstrated that S. mutans-induced enamel and dentin lesions exhibited increased fluorescence in the red and green spectral regions, with the signal stronger in the red region. In the blue region, however, fluorescence signals in the corresponding area were below the background level. Significantly weaker or virtually no fluorescence was detected in lactic acid-demineralized lesions at all excitation wavelengths. Neither bacterial cells nor culture media generated any fluorescence. These results indicate that, although the presence of S. mutans may be a prerequisite for the emission of fluorescence from carious lesions, some interaction of S. mutans with exposed tooth matrix elements may also be required for the generation or unmasking of fluorophores.     

Protective effect of a vegetable extract from Lupinus<Emphasis Type="Italic"> albus</Emphasis> (LU 105) on human gingival elastic fibers degradation by human leukocyte elastase

The aim of this study was to determine if a vegetable extract from seeds of Lupinus albus (LU 105) has the capacity to inhibit human leukocyte elastase and/or protect gingival elastic fibers against proteolytic degradation. LU105 was extracted from seeds of L albus and is freely soluble in water. In this study the ex-vivo elastolytic activity of human leukocyte elastase and the potential inhibitory effect of LU 105 were determined using human gingival cryostat tissue sections and computerized morphometric analysis. The gingival tissue sections pre-treated or not with LU 105 were submitted to the action of human leukocyte elastase or submitted to the simultaneous action of human leukocyte elastase and LU 105, and then analyzed using automated image analysis. In such conditions, LU 105 at 0.1%, 0.01%, and 0.001% developed a dose dependent protection of gingival elastic fibers against enzymatic proteolysis due to human leukocyte elastase, and LU 105 at 0.1% or 0.01% was able to inhibit the elastolytic activity of leukocyte elastase itself. It is proposed that LU 105 is an option for the treatment of gingival inflammation in which leukocyte elastase is involved.     

Oral lichen planus treated with 13-<Emphasis Type="Italic">cis</Emphasis>-retinoic acid (isotretinoin): effects on the apoptotic process

The aim of the present study is to verify the efficacy of isotretinoin in oral lichen planus (OLP). In a double-blind study, ten patients with biopsy-proven OLP were treated for 4 months with 0.1% isotretinoin gel and another ten patients with placebo. At the end of the first period of observation, the patients who had been given the placebo were given isotretinoin for a further 4 months. A complete response was defined as the disappearance of the lesions as assessed by inspection, whereas a partial response was defined as a 50% or more reduction in the size of the lesions. All patients treated with isotretinoin showed a significant improvement of the oral lesions, whereas in the patients who were given the placebo, the size of the lesions remained the same. The patients who were given isotretinoin after the placebo showed a reduction in lesions. In total, there were ten complete and ten partial responses. Lesions were analysed histologically and immunohistochemically with antibodies against bcl-2 and Ki-67. Ki-67 and bcl-2 have statistical significant increased values from before to after treatment, whereas apoptotic bodies decreased one. All these facts could have contributed to the partial or complete regression of OLP lesions. The increase in Ki-67 positive cells show that the epithelium requires for enhanced proliferation and healing. The present results revealed a disturbed cell death programme in OLP that could underline an abnormal epithelial differentiation. The results of this pilot study show that the topical use of isotretinoin is effective in treating OLP.     

Dental caries experience in relation to salivary findings and molecular identification of <Emphasis Type="Italic">S. mutans</Emphasis> and <Emphasis Type="Italic">S. sobrinus</Emphasis> in subjects with Down syndrome

This study investigated the association between clinical and salivary or molecular parameters in Down syndrome subjects. Sixty individuals (1- to 48-year old) were clinically examined using DMFT/DMFS. Stimulated saliva was collected; salivary flow was calculated (mL/min), buffering capacity was measured using a standard pH tape. In addition, 25 μL of saliva was diluted using 10-fold-dilution method and then placed on Mitis-Salivarius-Bacitracin agar to count colony forming units (CFU/mL) of mutans streptococci. Polymerase chain reaction analysis identified species. Caries indexes were 0.65–13.5 (DMFT) and 0.65–26.0 (DMFS) according to groups. Ninety-four percent of subjects had low flow rate (0.7–1.0 mL/min) and 44% had low buffering capacity (pH < 4). Besides, 60% had more than 1 × 10⁶ CFU/mL, 60% had S. mutans, and 41.4% had S. sobrinus. Caries indexes did not significantly correlate with flow rate, buffering capacity, CFU/mL by Pearson’s correlation (p > 0.05), and showed no significant association with prevalence of species by Chi-square (p > 0.05). There is no association between clinical picture and salivary or molecular parameters in Down syndrome subjects.     

Clinical and antibacterial effect of an anti-inflammatory toothpaste formulation with <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> extract on experimental gingivitis

It was the aim of the study to evaluate the clinical and antibacterial effect of a dentifrice containing an anti-inflammatory plant extract (SB) versus a placebo (PLA) using an experimental gingivitis model. Forty subjects (20 per group) discontinued all oral hygiene measures for four teeth for a period of 21 days using a shield (to generate a possible gingivitis) while they could brush the other teeth normally. After brushing, the shield was removed and teeth were treated with the randomly assigned toothpaste slurry for 1 min. Löe and Silness gingival index (GI), Silness and Löe plaque index (PI), and biofilm vitality (VF%) were assessed at days 0, 14, and 21, respectively. Subjects of the PLA group developed a GI of 0.82?±?0.342 (day 14) and 1.585?±?0.218 (day 21), while the data of the SB group were significantly reduced (0.355?±?0.243 and 0.934?±?0.342, p?相似文献   

Detection of salivary antibodies to crude antigens of <Emphasis Type="Italic">Opisthorchis viverrini</Emphasis> in opisthorchiasis and cholangiocarcinoma patients

Opisthorchis viverrini (O. viverrini; known as human liver fluke) is a major health problem in the northeastern region of Thailand. Infection with O. viverrini is the cause of hepatobiliary disease and cholangiocarcinoma (CCA). Previous studies demonstrated specific antibodies to crude O. viverrini antigens in serum from O. viverrini-infected patients. However, no studies have measured specific antibodies to O. viverrini antigens in saliva from patients with opisthorchiasis and CCA. The objective of the study was to detect specific antibodies to crude O. viverrini antigens in saliva from patients with opisthorchiasis and CCA, and to evaluate their use for diagnosis of O. viverrini infection. Saliva samples from 23 control subjects, 30 opisthorchiasis patients, and 38 CCA patients were collected. ELISA was established for detection of salivary IgA and IgG to crude O. viverrini antigens. ANOVA was used to compare salivary IgA and IgG levels among groups. Salivary IgA to crude O. viverrini antigens in CCA patients was significantly higher than controls (p = 0.007). Salivary IgG in CCA patients was significantly higher than opisthorchiasis patients and controls (p = 0.010 and p < 0.001, respectively). The cut-off value from salivary IgG test demonstrated higher accuracy for positivity of O. viverrini infection than salivary IgA. In conclusion, specific antibodies to crude O. viverrini antigens were detected in saliva of patients with opisthorchiasis and CCA. Salivary antibodies reflect serum immune response to O. viverrini infection, and salivary IgG tends to be a good candidate for diagnosis of O. viverrini infection.     

Occurrence of oral <Emphasis Type="Italic">Candida</Emphasis> colonization and its risk factors among patients with malignancies in China

Objectives

Oral colonization of Candida could lead to later development of oropharyngeal candidiasis or candidemia among the immunocompromised patients. This study aims to describe the occurrence and risk factors of oral Candida colonization in patients with malignancies.

Materials and methods

From October 2012 to March 2013, 78 patients with pulmonary cancer (group I), 101 patients with gastrointestinal tract tumor (group II), 79 patients with hematopoietic system malignant tumor (group III), and 101 healthy controls were consecutively recruited in a hospital in Beijing, China. The oral rinse samples were taken and Candida species were identified; the enzymes activities were tested.

Results

In total, 110 and 27 Candida strains were isolated from 91 patients and 26 controls, respectively. The oral colonization rate with Candida albicans in group III (12.7 %) was significant lower than that in group I (30.8 %), group II (33.7 %), and control group (25.7 %). The oral colonization rates with non-albicans Candida species in group I, group II, and group III were 15.4, 10.9, and 12.7 %, respectively, while only one non-albicans Candida strain was identified in control group. The non-albicans Candida species exhibited a lower virulence than C. albicans. Age was an independent risk factor for Candida colonization in patients with pulmonary cancer and digestive tract malignant tumor, “Teeth brush <1 time/day” was an independent risk factor for Candida colonization in patients with hematopoietic system tumor.

Conclusions

The differences of risk factors for oral Candida colonization in patients with different cancers require different strategies for the prevention and control of Candida infection.

Clinical relevance

Old aged patients with pulmonary cancer and digestive tract malignant tumor are high-risk population for Candida colonization. Increasing frequency of teeth brush might be helpful for preventing Candida colonization.

     

The effect of smear layer removal on <Emphasis Type="Italic">E. faecalis</Emphasis> leakage and bond strength of four resin-based root canal sealers

Background

The aim of the study was to assess bacterial sealability and bonding ability of methacrylate-based Resilon (RS, SybronEndo), Endo Rez (ER, Ultradent Products Inc), and epoxy-based AH Plus (AH, Dentsply/DeTrey), MTA Fill Apex (MTAF, Angelus Soluções Odontológicas) root canal sealers, and the effect of the smear layer removal on the sealability.

Methods

One hundred thirty root segments were instrumented up to apical size #60 and rinsed with 2.5% NaOCl. Half of the roots were rinsed with 5ml 17% EDTA to remove the smear layer. All the roots were filled with AH, ER, MTAF sealers and gutta-percha, or RS with Resilon cones. After storage at 37°C for 7 days the samples were mounted into bacterial leakage assay for 50 days.Another 100 roots were instrumented and rinsed as described above, split longitudinally, cut into the cervical, middle and apical parts. The sealers were injected through the plastic mould on the dentin surface. After 7 days of incubation at 37°C, bond strength was tested using a notched-edge test fixture (Crosshead, Ultradent Products Inc.) and a universal testing machine (Lloyd Instruments).

Results

AH revealed the longest mean time for bacterial resistance by 29.4 and 36.8 days (with and without smear layer, respectively) followed by RS (15.1 and 24.7 days, respectively). The difference between materials was significant (p<0.001).Bond strength values ranged from 0.2± 0.1 to 3.5± 0.7 MPa and increased from the apical to the cervical third. In the apical third, AH showed the highest mean (SD) bond values 1.4 (0.4) MPa and 1.7 (0.6) MPa (with and without smear, respectively, followed by RS, 0.5 (0.1) MPa and 0.8 (0.1) MPa, respectively. The difference between materials was significant (p=0.001).

Conclusion

The effect of the smear layer removal on the sealability was material-dependent.

     

A fast Look–Locker method for <Emphasis Type="Italic">T</Emphasis><Subscript>1</Subscript> mapping of the head and neck region

Objective  A sequence for T ₁ relaxation time measurements that allows a high-resolution image to be obtained within a short acquisition time is described. Its application to the orofacial region is investigated. Methods  The sequence is based on the Look–Locker (LL) method and employs a magnetization-preparation pulse prior to data acquisition, with either a turbo-field echo (TFE) or turbo-field echo echo-planar imaging (TFEPI) sequence. We applied the multiple LL sequence by synchronizing the data acquisition with the virtual electrocardiogram. T ₁ results from the LL sequence were compared with those from the inversion recovery (IR) sequence. In an in vitro study, we evaluated the T ₁ maps of contrast medium at different concentrations. In an in vivo study, we evaluated the T ₁ maps in seven volunteers. Results  In the in vitro study, the correlation between the T ₁ values obtained from the LL sequence and those from the IR sequence was high, with an R ² of more than 0.99. For T ₁ values between 200 and 1,500 ms, the difference between the two methods was less than 7%. In the in vivo study, a high correlation was observed between the T ₁ values from the IR sequence and those from the LL sequence. The scan duration for the LL sequence was less than 3 min. Conclusion  Our method, based on the LL sequence, was found to be clinically useful for producing a T ₁ map.     

Potential synergistic effects of a mixture of mineral trioxide aggregate (MTA) cement and <Emphasis Type="Italic">Bacillus subtilis</Emphasis> in dental caries treatment

Bacillus subtilis is nonpathogenic in humans and produces a number of useful substances and, therefore, this bacterium is used in probiotic therapy. There have been trials of B. subtilis for patients with periodontitis, but not for patients with caries. Similarly, mineral trioxide aggregate (MTA) cement has been widely used for endodontic treatment, but there are few reports of its use for caries. Therefore, examinations were performed regarding the benefits of addition of B. subtilis to MTA cement for treatment of dental caries. Indirect pulp capping with a mixture of MTA cement and B. subtilis spore powder is effective for avoiding pulpectomy or tooth extraction in such cases (personal communication). This study was planned to examine the scientific basis of this clinical finding, with examination of possible synergistic effects of MTA cement and B. subtilis. From these experiments, the following five results were obtained: (1) B. subtilis did not proliferate in liquid-culture media at pH ≥10. (2) B. subtilis proliferated when mixed with MTA cement. (3) There was no significant difference in proliferation of B. subtilis under aerobic and microaerobic conditions. (4) B. subtilis exhibited antibacterial effects on Staphylococcus aureus and Lactobacillus casei. (5) MTA cement exhibited antibacterial effects on S. aureus and Streptococcus mutans, but not on B. subtilis. These results support the hypothesis that a combination of B subtilis and MTA cement is likely to be clinically useful for treatment of dental caries.