Molecular detection of Aggregatibacter actinomycetemcomitans on metallic brackets by the checkerboard DNA-DNA hybridization technique

Microbial contamination profile on esthetic elastomeric ligatures through the checkerboard DNA-DNA hybridization technique : A randomized split-mouth study

OBJECTIVE

The aim of this study is to assess the microbial contamination of three different brands of esthetic elastomeric ligatures.

MATERIALS AND METHODS

Different brands of esthetic ligatures (Unistick Pearl [American Orthodontics, Sheboygan, WI, USA], Power Sticks Pearl [Ortho Technology, Tampa, FL, USA], and Ease [Obscure, 3M Unitek, Monrovia, CA, USA]) were randomly assigned to permanent canines of 25 patients (aged 11-18 years) undergoing corrective orthodontic treatment. After 30 days, the ligatures were removed, processed, and the biofilm composition was analyzed by checkerboard DNA-DNA hybridization for 40 bacterial species. The microbiological data were analyzed using a nonparametric mixed model.

RESULTS

The ligatures presented intense microbial contamination after 30 days, but no statistically significant differences were observed among the three groups (p > 0.05). The levels of the evaluated individual species and proportions of the microbial complexes showed no statistically significant differences among the ligature groups (p > 0.05).

CONCLUSIONS

Esthetic elastomeric ligatures became multicolonized by several bacterial species after 30 days of exposure to the oral cavity. However, no relevant differences were observed among the biofilm composition formed on the different ligature brands.

Assessment of microbial contamination in removable orthodontic appliances with and without the use of antimicrobial agents by checkerboard DNA-DNA hybridization analysis

INTRODUCTION

This clinical, crossover, double-blind trial evaluated the microbial contamination of removable orthodontic appliances used by children and the efficacy of 0.12% chlorhexidine gluconate spray use for disinfection.

METHODS

Twenty children aged 7-11 years were instructed to wear removable orthodontic appliances for 1 week. They were instructed to use a placebo solution (control) or 0.12% chlorhexidine gluconate (experimental) to clean the appliances on days 4 and 7 after installation. After this period, the microbial contamination on the surfaces of the appliance was analyzed using checkerboard DNA-DNA hybridization for 40 bacterial species. Data were analyzed by Fisher exact, t, and Wilcoxon tests (α = 0.05).

RESULTS

Removable orthodontic appliances were heavily contaminated by the target microorganisms. Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, and Eikenella corrodens were found in 100% of the appliances. Among cariogenic microorganisms, Streptococcus mutans and Streptococcus sobrinus were more abundant than Lactobacillus acidophilus and Lactobacillus casei. Red complex pathogens were more abundant than orange complex species. Purple complex bacteria were the most prevalent among bacterial complexes not associated with specific pathologies, detected in 34% of the samples. After the use of chlorhexidine, the number of cariogenic microorganisms (S. mutans, S. sobrinus, and L. casei) decreased significantly (P <0.05), and the numbers of periodontal pathogenic species from the orange and red complex also decreased significantly (P <0.05). There was no reduction for Treponema socranskii.

CONCLUSIONS

Removable orthodontic appliances were densely contaminated by several bacterial species. Twice-a-week application of chlorhexidine spray effectively reduced cariogenic and orange and red complex periodontal pathogens.

Sports mouthguards: Contamination, roughness, and chlorhexidine for disinfection - A randomized clinical trial

The aim of the present in vivo study was to evaluate the bacterial contamination of sports mouthguards, surface roughness, and the efficacy of chlorhexidine gluconate spray in the disinfection of these devices. A randomized, blinded cross-over clinical trial was performed with twenty 9 to 13 years old children who practiced martial arts and participated in all phases of the study. They were instructed to wear mouthguards 3 alternated days a week for 1 hour and, after use, to spray sterile tap water or chlorhexidine 0.12%. The mouthguards were analyzed by MTT assay, Checkerboard DNA-DNA hybridization, and confocal laser microscopy prior and after use for 2 weeks. Data were analyzed by Wilcoxon and t-Student, and Pearson correlation tests, with 5% significance level. Were observed that mouthguards of the control group were more contaminated with cariogenic microorganisms than those of the chlorhexidine group (p<0.05). The mouthguards use of spray of chlorhexidine reduced significantly the bacteria contamination compared with control group (p = 0.007). The surface roughness of the mouthguards increased significantly after use, irrespective of application of chlorhexidine spray. A moderate correlation (r=0.59) was observed between surface roughness and the cariogenic microorganism's contamination only for control group. Sports mouthguards had intense microbial contamination and increased surface roughness after its use. The use of chlorhexidine spray was effective for reducing the mouthguards contamination used by children.

Streptococcus mutans adherence to conventional and self-ligating brackets: an in vitro study

INTRODUCTION

Although self-ligating brackets presumably provide better hygiene conditions, no consensus has been reached so far.

OBJECTIVE

Therefore, the objective of this study was to evaluate, in an in vitro experimental design, the adherence of Streptococcus mutans (SM) in self-ligating and conventional brackets of different manufacturers and ligature types.

METHODS

Four commercial brands of maxillary premolar metal brackets were tested (Abzil®; Morelli®; 3M Unitek®; and GAC®). Each one was subdivided into three groups, which varied according to the type of ligature and bracket model (metallic, elastic, and self-ligating), totalizing twelve groups, composed of six brackets each. Previously sterilized brackets were initially immersed in saliva for one hour, and subsequently washed and added in a bacterial suspension, maintained in aerobiosis for 72 hours. The adhered bacteria were then separated and quantified by colony forming units (CFU/mL) counting after 48 hours of growth. The groups were compared by Kruskal-Wallis and Dunn post-hoc tests (p< 0.05).

RESULTS

Regardless of the commercial brand, self-ligating brackets had significantly less CFU/mL. However, according to comparisons performed within each commercial brand, only Abzil® self-ligating brackets had significantly lower biofilm adhesion. Among all of the self-ligating models, GAC® brackets presented the highest bacterial adhesion rate.

CONCLUSIONS

Self-ligating brackets are likely to present lower rates of biofilm adhesion. Particularly, Abzil® and GAC® self-ligating brackets are less likely to accumulate biofilm. Although such results are derived from an in vitro study, practitioners might acknowledge findings concerning bacterial adhesion as one of the relevant features to be considered during bracket selection.

Taxonomic Analysis of Oral Microbiome during Orthodontic Treatment

Background

Orthodontic appliances induce significant changes in the oral microbiome, but this shift in microbial composition has not been well established by the available evidence yet.

Objectives

To perform a systematic review of existing literature in order to assess the taxonomic microbial changes in orthodontic patients during Fixed Appliance Treatment (FAT) and Clear Aligner Treatment (CAT), using next-generation sequencing (NGS) technique of the bacterial 16S rRNA gene. Search Methods and Selection Criteria. The search for articles was carried out in PubMed, including articles published in English until May 2021. They included every human study report potentially relevant to the review. Data Collection and Analysis. After duplicate study selection and data extraction procedures according to the PICOS scheme, the methodological quality of the included papers was assessed by the Swedish Council on Technology Assessment in Health Care Criteria for Grading Assessed Studies (SBU) method.

Results

The initial search identified 393 articles, 74 of which were selected by title and abstract. After full-text reading, six articles were selected according to inclusion criteria. The evidence quality for all the studies was moderate.

Conclusions

Orthodontic treatment seems to transiently affect the composition of subgingival microbiome, although not salivary, maintaining a stable microbial diversity. Different results were found in the shift of microbiome between plaque and saliva, depending on the type of orthodontic treatment. This review should be interpreted with some caution because of the number, quality, and heterogeneity of the included studies.

Should local drug delivery systems be used in dentistry?

In dentistry, the use of biomaterial-based drug delivery systems (DDS) aiming the release of the active compounds directly to the site of action is slowly getting more awareness among the scientific and medical community. Emerging technologies including nanotechnological platforms are offering novel approaches, but the majority are still in the proof-of-concept stage. This study critically reviews the potential use of DDS in anesthesiology, oral diseases, cariology, restorative dentistry, periodontics, endodontics, implantology, fixed and removable prosthodontics, and orthodontics with a special focus on infections. It also stresses the gaps and challenges faced. Despite numerous clinical and pharmacological advantages, some disadvantages of DDS pose an obstacle to their widespread use. The biomaterial's biofunctionality may be affected when the drug is incorporated and may cause an additional risk of toxicity. Also, the release of sub-therapeutic levels of drugs such as antibiotics may lead to microbial resistance. Multiple available techniques for the manufacture of DDS may affect drug release profiles and their bioavailability. If the benefits outweigh the costs, DDS may be potentially used to prevent or treat oral pathologies as an alternative to conventional strategies. A case-by-case approach must be followed.

Alteration of the oral microbiota may be a responsible factor, along with estrogen deficiency, by the development of larger periapical lesions

OBJECTIVES

To answer the questions: (1) Does reducing estrogen levels influence the microbial composition of the oral cavity? (2) Does the presence of periapical lesion (PL) cause changes in the oral microbiota? (3) Since estrogen deficiency alters the oral microbiota, can this be one of the factors that contribute to the increase of the PL?

MATERIALS AND METHODS

Thirty-six rats were divided into four groups: sham (control), ovariectomy (OVX), control with PL (Sham + PL), and OVX + PL. After 9 weeks of OVX, the lower first molars were submitted to PL induction. After 21 days, the microbiological collection of the oral cavity was performed, and the animals were euthanized. The contents were evaluated by the checkerboard DNA-DNA hybridization method, to verify the prevalence of 40 bacterial species (divided into 7 microbial complexes). The blocks containing the lower first molars were submitted to histotechnical processing and staining with hematoxylin and eosin (HE), for the measurement of the periapical lesion area. The results were submitted to ANOVA and Kruskal-Wallis tests and Tukey and Dunn post-tests, with a significance level of 5%.

RESULTS

In conditions of estrogen deficiency, there was alteration of the oral microbiota. The OVX groups had a higher amount of bacteria compared to the SHAM group in most of the microbial complexes (p < 0.001). The animals in the control group (with or without lesion) did not present a statistically significant difference (p > 0.001) in any of the microbial complexes. The PLs in OVX animals were significantly higher compared to SHAM animals (p < 0.001).

CONCLUSIONS

Hypoestrogenicity conditions interfere in the oral microbiota by increasing the amount of bacteria in the saliva and influencing the progression of periapical lesions.

CLINICAL RELEVANCE

This inedited study shows that deficiency of estrogen leads to alteration of the oral microbiota.

The Microflora Diversity and Profiles in Dental Plaque Biofilms on Brackets and Tooth Surfaces of Orthodontic Patients

Objective: Fixed orthodontic appliances may influence the oral environment through accumulation of plaque, decreased plaque pH, and increased gingival inflammation. These changes in the oral cavity can potentially lead to periodontal disease, demineralization, and other infectious diseases.

Materials and Methods: To investigate the changes in biofilm throughout the initial 2 weeks, we placed a stainless steel bracket on the upper second premolar and collected plaque samples on the bracket and on the tooth surface at different time points (0, 24, 48 h and 1 and 2 weeks) and plated on tryptic soy agar blood agar plate, and kept at 37°C in an anaerobic chamber for 5 days to determine the CFUs of bacteria. At the end of 2 weeks, we removed the bracket and elastomeric module, and we isolated genomic DNA from the bacterial biofilm for identification of bacteria by 16S rRNA PCR analysis. We also analyzed the morphology of biofilm on the bracket by scanning electron microscope.

Results: Our results show that the bacterial biofilm was significantly increased on the bracket in all the subjects, whereas on the tooth surface, the CFUs were not significantly increased. PCR assay showed that biofilm on orthodontic brackets from all subjects showed colonization by Streptococcus gordonii, Porphyromonas gingivalis and Streptococcus mutans were observed on some of the subjects after 48 h, whereas Aggregatibacter actinomycetemcomitans biofilm was observed in all the time points except 24 h.

Conclusion: This study demonstrated that both periodontal and cariogenic bacterial biofilms were formed on the bracket as early as 24 h.

Orthodontic appliances did not increase risk of dental caries and periodontal disease under preventive protocol

OBJECTIVES

To assess periodontal parameters and microbial species levels after orthodontic appliance placement in patients who received oral hygiene instructions and who were monitored and motivated throughout the study.

MATERIALS AND METHODS

The Periodontal Index was recorded and saliva collection was performed before (T0) and 30 (T1), 60 (T2), and 90 (T3) days after orthodontic appliance placement in 15 patients (mean age 17.53 ± 8.0 years). Analysis was carried out using checkerboard DNA-DNA hybridization. Nonparametric statistical analysis was performed.

RESULTS

The Periodontal Index did not change. The total amount of the purple and red complexes and Candida species showed a significant decrease from T2. The green, yellow, and orange complex showed a significant decrease at T3. The specific species analysis showed that Prevotella nigrescens, Pseudomonas putida, Fusobacterium periodonticum, Pseudomonas aeruginosa, Peptostreptococcus anaerobius, and Tanerella forsythia showed high incidence before bonding, and their levels decreased at T2 and T3. Only Porphyromonas gingivalis showed increased levels at T2 and displayed the highest level at T3. The Streptococcus group decreased their levels from T2 onward.

CONCLUSIONS

A dynamic change in microbial levels was identified. The decrease in the levels of complexes present was only possible due to the mechanical method of oral hygiene implemented in this sample.

Successful and failed mini-implants: microbiological evaluation and quantification of bacterial endotoxin

Objectives

Using two groups of mini-implants (successful and failed) the objectives of this in vivo study were: to evaluate the microbial contamination by the checkerboard DNA-DNA hybridization technique and to quantify the bacterial endotoxin by the limulus amebocyte lysate assay.

Material and Methods

The 15 successful and 10 failed mini-implants (1.6 mm diameter × 7.0 or 9.0 mm long), placed in the maxilla and/or mandible, were obtained from 15 patients undergoing orthodontic treatment. Data were analyzed statistically by the Wilcoxon rank-sum test using the SAS software (a=0.05).

Results

All 40 microbial species were detected in both groups of mini-implants, with different frequencies. No differences were observed between the groups with respect to microbial complexes (blue, purple, yellow, green, orange, red and other species) and endotoxin quantification (p>0.05).

Conclusion

Neither microbial contamination nor endotoxin quantification was determinant for the early loss of stability of the mini-implants.

Assessment of the effectiveness of mouthwashes in reducing cariogenic biofilm in orthodontic patients: a systematic review

OBJECTIVES

The use of fixed orthodontic appliances makes it difficult to clean the teeth and accessories associated with it. For this reason, orthodontic patients have used oral antiseptics as coadjuvent means to reduce cariogenic plaque. The aim of this systematic review was to evaluate the effectiveness of oral antiseptics on the reduction of cariogenic plaque on orthodontic patients.

DATA

This review has been registered at PROSPERO--international prospective register of systematic reviews under the number CRD42013006857.

SOURCES

A systematic review of the literature was conducted in the following electronic databases: Scopus, PubMed, Web of Science, Medline, Embase and Cochrane, Grey literature and Clinical Trials, without limitations on the year of publication or language. Clinical studies in patients with fixed orthodontic appliances, who were making use of oral mouthwashes in order to reduce cariogenic plaque, were included. Articles with patients using systemic drugs, syndromic patients, those using mouthwashes for other purposes and/or using different cleaning techniques, and clinical cases were excluded. After selection by title and abstract, potentially eligible articles were read in full. The methodological quality and risk of biases of articles included were evaluated according to the characteristics of the study, measurements and statistical analyses of the study. The methodological quality was classified as high, moderate or low.

STUDY SELECTION

The search identified 2716 articles, of which 15 met the inclusion criteria. Of these, 8 analyzed chlorhexidine-based mouthwashes, while in 1 article Cetylpyridinium was used; 1 analyzed the mouthwash containing sanguinaria; 1 the use of NaF; 2 articles the use of AmF/SnF2; 2 the use of Listerine(®), 1 also analyzed the association between mouthwashes with octenidine and with PVP-I. Of the articles analyzed, 11 were classified as having high and 4 as having moderate methodological quality.

CONCLUSION

There is evidence of effectiveness of the use of oral mouthwashes in the control of cariogenic plaque in patients with fixed orthodontic appliances. The orthodontists may suggest the use of oral antiseptics in the oral hygiene of their patients as coadjuvent means to reduce cariogenic plaque.

CLINICAL SIGNIFICANCE

Given current evidence, orthodontists may prescribe mouthwash as an auxiliary method in the control of cariogenic biofilm in orthodontic patients.

Absence of interleukin 22 affects the oral microbiota and the progression of induced periapical lesions in murine teeth

AIM

To evaluate the absence of IL-22 on the progression of periapical lesions in wild-type (WT) and IL-22 knockout (IL-22 KO) mice.

METHODOLOGY

The evaluation of the oral microbial profile of mice was performed by Checkerboard DNA-DNA hybridization from saliva samples. Periapical lesions were induced in manbibular first molars by pulpal exposure and evaluated after 7, 21 and 42 days (n = 15). Haematoxylin-eosin-stained sections were analysed under conventional and fluorescence microscopy to evaluate the tissue features and size of periapical lesions and tartrate-resistant acid phosphatase histoenzymology (TRAP), Brown & Brenn staining and immunohistochemistry. The scores of the number of bacterial cells present in the oral cavity were analysed by the Mann-Whitney test, and the results and comparisons for periapical lesion size and number of osteoclasts were subjected to one-way anova and Bonferroni's post-test (α = 0.05).

RESULTS

Significant differences were observed for bacterial load between the groups of animals for 6 bacterial species (P < 0.05), with five species found in higher levels in the WT group, and one in the IL-22 KO group. WT mice had significantly larger periapical lesions (P < 0.05) between 7 and 42 days and between 21 and 42 days, with an increase in the mean size and number of osteoclasts. IL-22 KO mice had an increase in periapical lesion size and number of osteoclasts between 7 and 21 days (P < 0.05). No differences were found between bacteria localization in the root canal system between the experimental groups. Small variations related to the location of immunostaining were found between the groups.

CONCLUSION

This study revealed differences in the composition of oral microbiota between mice that may be taken into account in the susceptibility to infections and development of periapical lesions. The absence of IL-22 in mice resulted in smaller periapical lesions with fewer osteoclasts at the final experimental period, suggesting the participation of IL-22 in the host immune and inflammatory response to a periradicular infection.