Antibacterial Activity of Two Chemomechanical Caries Removal Gels on Carious Dentin of Primary Teeth: An in vitro Study.

INTRODUCTION: Chemomechanical caries removal (CMCR) is an effective method of caries removal especially for primary teeth as they cause less discomfort when compared with conventional caries removal. The most significant thing about caries removal is the elimination of cariogenic bacteria. This study compares the antibacterial activity of two CMCR gels. MATERIALS AND METHODS: A total of 40 primary molar teeth with carious dentin were split along the long axis in a laboratory. Total viable count (TVC) was taken for the teeth before splitting as a measure of colony-forming units per milliliter (CFU/mL). Each half was treated with either Carisolv or Carie-Care CMCR gels. Clean dentin samples were evaluated for Streptococcus mutans (SM) and Lactobacillus acidophilus (LB) after removal of carious tissue using the caries removal gels using serial dilutions and incubating on specific agar plates. RESULTS: The results showed significant reduction in mean TVC after use of both the CMCR gels. Both gels reduced the CFU/mL of SM and LB to a significant level (p < 0.05). However, there was no significant difference between the antibacterial activities of the two CMCR gels. CONCLUSION: The CMCR gels (Carisolv and Carie-Care) significantly reduced the residual TVC as well as SM and LB in carious primary dentin. Both CMCR gels had a similar antibacterial activity on the carious dentin of primary teeth. CLINICAL SIGNIFICANCE: The CMCR gels tested have a significant antibacterial activity and can be effectively used for elimination of caries-causing bacteria in primary teeth.

An investigation of the effect of scaling-induced surface roughness on bacterial adhesion in common fixed dental restorative materials.

STATEMENT OF PROBLEM: Bacterial plaque must be routinely removed from teeth, adjacent structures, and prostheses. However, the removal of this plaque can inadvertently increase the risk of future bacterial adhesion. PURPOSE: The purpose of this investigation was to assess the change in the surface roughness of 3 different surfaces after dental prophylactic instrumentation and how this influenced bacterial adhesion. MATERIAL AND METHODS: Forty specimens each of Type III gold alloy, lithium disilicate, and zirconia were fabricated in the same dimensions. The specimens were divided into 4 groups: ultrasonic scaler, stainless steel curette, prophylaxis cup, and control. Pretreatment surface roughness measurements were made with a profilometer. Surface treatments in each group were performed with a custom mechanical scaler. Posttreatment surface roughness values were measured. In turn, the specimens were inoculated with Streptococcus mutans, Lactobacillus acidophilus, and Actinomyces viscosus. Bacterial adhesion was assessed by rinsing the specimens with sterile saline to remove unattached cells. The specimens were then placed in sterile tubes with 1 mL of sterile saline. The solution was plated and quantified. Scanning electron microscopy was performed. The statistical analysis of surface roughness was completed by using repeated-measures single-factor ANOVA with a Bonferroni correction. RESULTS: The surface roughness values for gold alloy specimens increased as a result of prophylaxis cup treatment (0.221 to 0.346 Ra) (P<.01) and stainless steel curette treatment (0.264 to 1.835 Ra) (P<.01). The results for bacterial adhesion to gold alloy proved inconclusive. A quantitative comparison indicated no statistically significant differences in pretreatment and posttreatment surface roughness values for lithium disilicate and zirconia specimens. In spite of these similarities, the overall bacterial adherence values for lithium disilicate were significantly greater than those recorded for gold alloy or zirconia (P<.05). Instrumentation of the lithium disilicate and zirconia with the stainless steel curette significantly increased bacterial adhesion compared with the control (P<.05). CONCLUSIONS: The results of this investigation indicate that Type III gold alloy exhibited increased surface roughness values after stainless steel curette and prophylaxis cup treatments. Zirconia was less susceptible to bacterial adhesion than lithium disilicate, and greater bacterial adhesion was found for the stainless steel curette than the other instrumentation methods.

An in vitro study on the secondary caries-prevention properties of three restorative materials.

STATEMENT OF PROBLEM: Secondary caries is considered to be the most important and common reason for the replacement of all types of restorations. PURPOSE: The purpose of the study was to evaluate in vitro both the anticaries efficacy and marginal integrity of amalgam, glass ionomer cement, and composite resin restorations in a cariogenic condition. MATERIAL AND METHODS: Class II cavities were prepared on 60 extracted teeth, which were assigned to 3 groups and restored either with amalgam, glass ionomer, or composite resin. After thermal cycling and sterilization, the teeth were set in an artificial carious environment for 10 days. The bacteria from the margin of the restorations were then collected, and microleakage was evaluated by means of dyeing. According to the locations, the demineralization of tooth tissue around the restoration was divided into 3 parts: artificial outer lesion, artificial enamel wall lesion, and artificial dentin wall lesion. The depths of the artificial outer lesion and the areas of the artificial enamel and dentin wall lesions were investigated with a confocal laser scanning microscope after all the specimens had been stained with 0.1 mM Rhodamine B. Statistical analyses consisted of 1-way ANOVA and Kruskal-Wallis tests (α=.05). RESULTS: No significant difference was noted in terms of the number of bacteria around the restorations for the 3 materials; the microleakage of amalgam was the least among the 3 types of restorations; the outer enamel lesion depth around the glass ionomer cement was the lowest, and the wall lesion area around the amalgam was the smallest. CONCLUSIONS: No definite inhibitory effect of fluoride releasing restorative materials (glass ionomer) was apparent on Lactobacillus acidophilus in this study. The amalgam restorations showed the best marginal integrity and the smallest artificial wall lesion among the 3 types of restorations.

Effects of 2 bracket and ligation types on plaque retention: a quantitative microbiologic analysis with real-time polymerase chain reaction.

INTRODUCTION: The aim of this study was to evaluate the effects of self-ligating brackets and conventional brackets ligated with stainless steel ligatures on dental plaque retention and microbial flora. METHODS: Twenty boys (mean age, 14.2 ± 1.5 years) underwent bonding with self-ligating bracket systems and conventional standard edgewise bracket systems ligated with stainless steel ligatures with a split-mouth design. Clinical measurements, including plaque index, probing pocket depth, and bleeding on probing, were obtained before bonding, 1 week after bonding, and 3 months after bonding. Supragingival plaque samples were obtained at baseline and 3 months after bonding for the detection of bacteria. A quantitative analysis for Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Lactobacillus acidophilus was performed using real-time polymerase chain reaction. The Mann-Whitney U test and the Hotelling T(2) multivariate test were used for statistical comparisons of the groups. RESULTS: The numbers of S mutans, S sobrinus, L casei, and L acidophilus were not statistically different between self-ligating brackets and conventional brackets ligated with stainless steel ligatures (P >0.05). The 2 archwire ligation techniques showed no statistically significant differences in plaque index, bleeding on probing, and probing pocket depth values of the bonded teeth (P >0.05). All clinical parameters and the numbers of all microorganisms showed statistically significant increases from baseline to 3 months after bonding in both groups (P <0.001). CONCLUSIONS: Self-ligating brackets and conventional brackets ligated with stainless steel ligatures do not differ with regard to dental plaque retention.

Polymerase chain reaction detection of Lactobacillus acidophilus in human oral cavity and fecal samples after 2-week consumption of yoghurt.

OBJECTIVE: To investigate whether short-term daily consumption of yoghurt leads to colonization by Lactobacillus acidophilus in a group of human subjects who were initially totally devoid of L. acidophilus in their oral cavities. MATERIAL AND METHODS: Twenty-three volunteers consumed yogurt containing L. acidophilus during a 14-day trial stage. Oral and fecal samples were collected at the clearance stage and at the post-yoghurt intake stage until L. acidophilus was found. Standard polymerase chain reaction methods using specific primers were adopted for the detection and identification of L. acidophilus. RESULTS: The isolation frequency decreased rapidly 72 h after stopping intake of yoghurt. After 1 week, L. acidophilus was absent in all oral samples. Non-significant differences were found between the survival rates of L. acidophilus in samples of saliva, plaque, tongue surface, and buccal mucosa. L. acidophilus was also found to remain in the gastrointestinal tract for longer than in the oral cavity. CONCLUSION: Allochthonous L. acidophilus is not likely to permanently colonize the oral cavity and intestine.

Selected aspects of the oral environment in cleft palate patients--a problem evidently beyond dentists' scope.

INTRODUCTION: The oral cavity is a specialized ecosystem composed of dentition and mucosa exposed to the effects of saliva and gingival liquid. Its structure provides advantageous conditions for various microorganisms, both aerobic streptococci and anaerobic bacilli. The dynamic balance of the oral cavity ecosystem can be threatened by various factors. Lip and palatal clefts are the most frequent disorders in embryonic facial development. The aim of the study was to evaluate whether Streptococcus mutans and Lactobacillus acidophilus and oral cavity hygiene in patients with cleft palate treated orthodontically are significantly different compared with patients without these congenital malformations. MATERIAL/METHODS: The study group consisted of 200 patients aged 6-21 who were divided into two groups depending on the presence of cleft palate and treatment method. Group C (control) consisted of 50 orthodontically untreated patients with occlusal dental defects. The performed studies consisted of 2 parts: the clinical-laboratory part and statistical analysis. Clinical-laboratory part RESULTS: High bacteria levels of Streptococcus mutans and Lactobacillus acidophilus in saliva of patients were comparably frequent between groups, but there were statistically significant differences in inter-group comparisons. CONCLUSIONS: As the orthodontic treatment changes the oral environment, control of proper hygienic behavior is an essential element of health education. Introduction of preventive programs is also very important.

Distribution of selected cariogenic bacteria in five different intra-oral habitats in young children.

BACKGROUND: Knowledge of the colonization patterns and composition of the oral microbiota can lead to a better understanding of disease initiation. AIM: The aim of this study was to examine the distribution of selected cariogenic bacteria in samples from five different oral habitats in young Greek children. DESIGN: Ninety-three children 3-12 years old (mean + SD 7.9 +/- 2.5) (60.2% male, 39.8% female) participated and split into three different age groups: primary (3-6 years), early mixed (6-9 years), and mixed dentition (9-12 years). Samples for bacterial enumeration were taken from saliva, supragingival and subgingival plaque, tongue dorsum, and soft tissues from each child, and were further analysed using checkerboard DNA-DNA hybridization. RESULTS: Mean counts and proportions of all the test bacteria differed significantly among sample locations. Cariogenic bacteria were present in almost all healthy children. Mean proportions of Streptococcus mutans isolated from soft tissue and Streptococcus sanguinis from soft tissue, subgingival and saliva samples increased significantly with age, whereas the opposite was seen for Lactobacillus acidophilus. CONCLUSIONS: Cariogenic bacteria were present in almost all young children. Soft tissues, saliva, and tongue were more often colonized by cariogenic streptococcal species than teeth. These surfaces may serve as reservoirs for oral pathogens, requiring attention during preventive interventions.

The effect of fiber-reinforced composite versus band and loop space maintainers on oral Lactobacillus acidophilus and Streptococcus mutans levels in saliva.

BACKGROUND: Orthodontic bands have been shown to alter oral microbial flora that lead to convert caries-free patients to moderate or high caries risk individuals. AIM: This study aimed to evaluate the effect of conventional band and loop space maintainers versus fiber-reinforced composite (FRC) resin space maintainer on the salivary cariogenic microflora (Lactobacillus and Streptococcus mutans) in children over a period of 6 months. MATERIALS AND METHODS: The study sample was divided equally into two groups: Group A: 25 patients received FRC (INFIBRA®: Reinforcing ribbon, Bioloren, Italy) space maintainer and Group B: 25 patients received band and loop space maintainers. The saliva samples were collected from the patients before the insertion of the space maintainer and at 2 weeks, 3 months, and 6 months postinsertion. RESULTS AND CONCLUSION: The Lactobacillus acidophilus isolated was 1.7 colony-forming unit (CFU) (×106) and 1.8 CFU (×106) in Group A and Group B, respectively, prior to the insertion of space maintainers. There was no significant increase in L. acidophilus over the follow-up of 6 months in both the groups (P > 0.05). However, the Streptococcus mutans isolated before insertion in both Group A and Group B was 2.6 CFU (×106), which over a period of 6 months showed significant increase to 3.13 CFU (×106) in Group B (P < 0.05) and no increase was seen in Group A. S. mutans level increased considerably in patients with band and loop space maintainer over the follow-up of 6 months. No significant increase in the L. acidophilus count was observed over the same period in both the groups.

Quantitative analysis of biofilm bacteria according to different stages of early childhood caries.

OBJECTIVE: Monitoring selected key species related to health or disease may facilitate caries risk assessment and discovery of novel ecological preventive and therapeutic approaches. This study aimed at quantifying Actinomyces naeslundii, Bifidobacterium spp., Lactobacillus acidophilus, Lactobacillus casei group, Streptococcus gordonii, Mitis group and Streptococcus mutans by quantitative polymerase chain reaction (qPCR) in dental biofilm from Brazilian children with different stages of early childhood caries (ECC). DESIGN: Seventy-five preschool children were clinically evaluated by ICDAS criteria and divided into groups: caries-free (CF; n = 20), enamel caries lesions (ECL; n = 17) and dentine caries lesions (DCL; n = 38). Plaque samples from all children were collected for detection and quantification of the selected bacteria. RESULTS: L. acidophilus and L. casei group were absent in almost all plaque samples. No differences in relative proportions of A. naeslundii, Mitis group and S. gordonii were observed in any stage of caries. However, S. mutans and Bifidobacterium spp. were present at higher concentrations in the biofilm of children with DCL (p < 0.001). Multivariate analysis showed that S. mutans and Bifidobacterium spp. were strongly associated with biofilm in children with DCL. CONCLUSION: Differences were observed in the proportion of acidogenic and aciduric bacteria with dental caries progression. The data indicate that S. mutans and Bifidobacterium spp. in dental biofilm may be involved in some progression processes for ECC.

Quantification of live Lactobacillus acidophilus in mixed populations of live and killed by application of attenuated reflection Fourier transform infrared spectroscopy combined with chemometrics.

Since culture-based methods are costly and time consuming, alternative methods are investigated for the quantification of probiotics in commercial products. In this work ATR- FTIR vibration spectroscopy was applied for the differentiation and quantification of live Lactobacillus (La 5) in mixed populations of live and killed La 5, in the absence and in the presence of enteric polymer Eudragit® L 100-55. Suspensions of live (La 5_L) and killed in acidic environment bacillus (La 5_K) were prepared and binary mixtures of different percentages were used to grow cell cultures for colony counting and spectral analysis. The increase in the number of colonies with added%La 5_L to the mixture was log-linear (r2 = 0.926). Differentiation of La 5_L from La 5_K was possible directly from the peak area at 1635 cm-1 (amides of proteins and peptides) and a linear relationship between%La 5_L and peak area in the range 0-95% was obtained. Application of partial least squares regression (PLSR) gave reasonable prediction of%La 5_L (RMSEp = 6.48) in binary mixtures of live and killed La 5 but poor prediction (RMSEp = 11.75) when polymer was added to the La 5 mixture. Application of artificial neural networks (ANNs) improved greatly the predictive ability for%La 5_L both in the absence and in the presence of polymer (RMSEp = 8.11 × 10-8 for La 5 only mixtures and RMSEp = 8.77 × 10-8 with added polymer) due to their ability to express in the calibration models more hidden spectral information than PLSR.

Isolation of microbial DNA by newly designed magnetic particles.

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) microspheres and cobalt ferrite nanoparticles modified with alginic acid (natural carboxylic polysaccharide) were used for isolation of microbial DNA of lactic acid bacteria (LAB) from dairy products, lyophilised cell cultures, and bacterial colonies grown on hard media, and Trichophyton fungi DNA from lyophilised cells. DNA from the samples with lysed cells was reversibly adsorbed to the particles in the presence of high poly(ethylene glycol) (PEG 6000) and sodium chloride concentrations. The optimal final PEG and NaCl concentrations were 9.1 wt.% and 2.0 M, respectively. The adsorbed DNA was released from the particles in low ionic strength TE buffer. The quality of isolated DNA was checked by PCR amplification. Moreover, PCR amplicons were isolated on cobalt ferrite nanoparticles modified with alginic acid and checked by restriction analysis.

Studies of the subgingival microflora in patients with acquired immunodeficiency syndrome.

Two unique forms of periodontal disease, HIV-gingivitis and HIV-periodontitis, have been described in patients with Acquired Immunodeficiency Syndrome (AIDS). In order to determine the bacterial species associated with periodontitis in AIDS patients, the predominant cultivable microflora was examined in 21 subgingival plaque samples from 11 AIDS patients with periodontitis. The presence of putative periodontal pathogens including Actinobacillus actinomycetemcomitans, Bacteroides intermedius, Porphyromonas gingivalis (formerly B. gingivalis), and Wolinella recta was examined by immunofluorescence in 128 subgingival dental plaque samples from 50 AIDS patients including 32 patients with periodontitis. Of 666 bacterial strains isolated from the 21 subgingival plaque samples, Streptococcus sanguis II was the most frequently recovered species comprising 18.5% of the total number of isolates followed by Lactobacillus acidophilus (12.2%), Porphyromonas gingivalis (12%), Fusobacterium nucleatum (11.4%), Staphylococcus epidermidis (8.7%), Actinomyces naeslundii (7.5%), and Actinomyces viscosus (4.7%). Fusobacterium nucleatum was the most prevalent species and was found in 76% of the sites and 91% of the patients. Enteric species including Enterococcus avium and Enterococcus faecalis, Clostridium clostridiiforme and Clostridium difficle as well as Klebsiella pneumoniae also were recovered. Immunofluorescence assays detected similar carriage rates of A. actinomycetemcomitans, B. intermedius, and P. gingivalis in both gingivitis patients and periodontitis patients, while four times more periodontitis patients demonstrated W. recta. Subgingival yeast was a frequent finding in these AIDS patients, present in 62% of the subjects and 55% of the sites. This study indicates that subgingival plaque in AIDS patients with periodontitis can harbor high proportions of the same periodontal pathogens as are associated with periodontitis in non-HIV infected subjects as well as high proportions of opportunistic pathogens.

[Lactobacillus acidophilus endocarditis]. / Endocardite à Lactobacillus acidophilus.

BACKGROUND: Lactobacillus is a commensal germ found in the buccal cavity, the digestive tract and the vagina. Usually non-pathogenic except in case of dental caries, it can occasionally be the causal agent in severe endocarditis. CASE REPORT: A 70-year-old woman developed endocarditis on an aortic valve bioprosthesis. Lactobacillus acidophilus was isolated from blood cultures of the valve after surgery. COMMENTS: Forty-four cases of Lactobacillus endocarditis have been reported in the literature to date. Mortality is high (26%). The main difficulty in treatment is germ tolerance to penicillin and aminosides found in all cases. Cure requires high dose parenteral antibiotics and surgery in many cases (26%).

[Submental abscess by Lactobacillus acidophilus/jensenii]. / Absceso submentoniano por Lactobacillus acidophilus/jensenii.

The different species of Lactobacillus genus are bacteria of a low pathogenicity. They are found in the gastrointestinal tract, the female genitourinary tract, and also as part of the anaerobic flora in the mouth. Due to this low pathogenicity, they are generally related with infections together with other with more virulent microorganisms, or in immunocompromised patients. In our case, Lactobacillus appears alone as an etiological agent in an immunocompetent patient with a submental abscess.

Adhesion forces and composition of planktonic and adhering oral microbiomes.

The oral microbiome consists of a planktonic microbiome residing in saliva and an adhering microbiome (the biofilm adhering to oral hard and soft tissues). Here we hypothesized that possible differences in microbial composition of the planktonic and adhering oral microbiome on teeth can be related to the forces by which different bacterial species are attracted to the tooth surface. The relative presence of 7 oral bacterial species in saliva and biofilm collected from 10 healthy human volunteers was determined twice in each volunteer by denaturing-gradient-gel electrophoresis. Analysis of both microbiomes showed complete separation of the planktonic from the adhering oral microbiome. Next, adhesion forces of corresponding bacterial strains with saliva-coated enamel surfaces were measured by atomic force microscopy. Species that were found predominantly in the adhering microbiome had significantly higher adhesion forces to saliva-coated enamel (-0.60 to -1.05 nN) than did species mostly present in the planktonic microbiome (-0.40 to -0.55 nN). It is concluded that differences in composition of the planktonic and the adhering oral microbiome are due to small differences in the forces by which strains adhere to saliva-coated enamel, providing an important step in understanding site- and material-specific differences in the composition of biofilms in the oral cavity.

Infectious endocarditis caused by Lactobacillus acidophilus in a patient with mistreated dental caries.

We present a rare case of infectious endocarditis caused by Lactobacillus acidophilus in a patient on long-term steroid use for autoimmune hepatitis. In vitro susceptibility-guided antibiotics with benzylpenicillin plus clindamycin and successive mitral annuloplasty resulted in a favorable outcome. Infectious endocarditis was suspected to be a complication of mistreated periodontal infection. Maintenance of oral hygiene is important in immunocompromised patients.

Use of the checkerboard DNA-DNA hybridisation technique for in vivo detection of cariogenic microorganisms on metallic brackets, with or without use of an antimicrobial agent.

OBJECTIVE: Using checkerboard DNA-DNA hybridisation (CDDH) assay, this randomised clinical study evaluated the contamination of metallic brackets by four cariogenic bacterial strains (Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei and Lactobacillus acidophilus) and the efficacy of 0.12% chlorhexidine gluconate (CHX) mouthwashes in reducing bacterial contamination. METHODS: Thirty-nine 11-33-year-old patients under treatment with fixed orthodontic appliances were enrolled in the study and had 2 new metallic brackets bonded to premolars. Nineteen patients used a 0.12% CHX mouthwash (Periogard) and 20 patients used a placebo mouthwash (control) twice a week. After 30 days, the brackets were removed and samples were obtained for analysis by CDDH. Data were analysed statistically by the Kruskal-Wallis test (α=0.05) using the SAS software. RESULTS: S. mutans, S. sobrinus, L. casei and L. acidophilus were detected in 100% of the samples from both groups. However, brackets of the control group were more heavily contaminated by S. mutans and S. sobrinus (P<0.01). In the experimental group, although all counts decreased after rinsing with the chlorhexidine solution, there was significant difference only for S. mutans (P=0.03). CONCLUSIONS: The use of 0.12% chlorhexidine gluconate mouthwashes can be useful in clinical practice to reduce the levels of cariogenic microorganisms in patients under treatment with fixed orthodontic appliances.

Dental health of 6-year-old children in Alpes Maritimes, France.

AIM: To describe the dental health status of 6-year-old children using the ICDAS-II advanced method and to evaluate the association between the known caries risk factors with the cavitated caries lesion (WHO basic method) or with both non-cavitated and cavitated caries lesion caries (ICDAS II). METHODS: In this cross-sectional study, a questionnaire was used to evaluate oral health and dietary habits of children. A clinical examination and a Cario analysis test (Pierre Fabre Oral care) were performed. STATISTICS: Logistic regression analyses were used to assess the association between caries and daily tooth-brushing, dietary habits, visible plaque and salivary factors. RESULTS: There were 341 children (52% female and 6.25+/-0.46 years of age) in this study. Using the ICDAS-II advanced method, 39% of the children were caries-free. This proportion was larger (67.2%) using the WHO method. In multivariate models, visible dental plaque and Streptococcus mutans count were associated with caries experience registered as ICDAS-II codes 1-6 or codes 3-6. The absence of daily tooth-brushing with fluoridated toothpaste was associated only with caries experience ICDAS-II codes 3-6. CONCLUSION: The use of WHO or ICDAS-II method changed the proportion of caries-free children but not the clinical caries risk factors associated with caries experience.