In-vivo evaluation of the contamination of Super Slick elastomeric rings by Streptococcus mutans in orthodontic patients

Influence of elastomeric and steel ligatures on periodontal health during fixed appliance orthodontic treatment: a systematic review and meta-analysis

INTRODUCTION

Metallic and elastomeric ligatures are widely used in orthodontics to secure the archwire within the bracket slots, but elastomeric ligatures have traditionally been associated with increased microbial colonization, which could adversely affect periodontal health.

AIM

This systematic review compares the periodontal effects of elastomeric and steel ligatures used for orthodontic fixed appliances.

METHODS

Unrestricted literature search of 7 databases (MEDLINE, Scopus, Web of Science, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Virtual Health Library) up to July 2023 were performed for randomized / non-randomized clinical studies on humans comparing the two ligation methods during fixed-appliance therapy. After duplicate study selection, data extraction, and risk-of-bias assessment with the Risk of Bias (RoB) 2 or the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) tool, random-effects meta-analyses of Mean Differences (MD) or Standardized Mean Differences (SMD) and their 95% confidence intervals (CIs) were carried out, followed by assessment of certainty of existing evidence with the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

A total of 11 studies (3 randomized / 8 non-randomized) with 354 patients (mean age 14.7 years and 42% male) were included. No statistically significant differences were seen for plaque index (5 studies; SMD = 0.48; 95% CI = -0.03 to 1.00; P = 0.07), gingival index (2 studies; MD = 0.01; 95% CI = -0.14 to 0.16; P = 0.89), probing pocket depth (2 studies; MD = 0; 95% CI = -0.17 to 0.16; P = 0.97), or Streptococcus mutans counts (4 studies; SMD = 0.40; 95% CI=-0.41 to 1.20; P = 0.21). Elastomeric ligatures were associated with moderately increased total bacterial load (3 studies; SMD = 0.43; 95% CI = 0.10 to 0.76; P = 0.03). Confidence in these estimates was low in all instances due to the inclusion of non-randomized studies with high risk of bias.

CONCLUSIONS

Existing low quality evidence indicates that ligature method does not seem to influence the periodontal health during fixed treatment, even if elastomeric ligatures are associated with a moderate increase of bacterial load.

REGISTRATION

PROSPERO (CRD42023444383).

Antibacterial coating of orthodontic elastomeric ligatures with silver and bismuth nanofilms by magnetron sputtering: A feasibility study

OBJECTIVES

Magnetron sputtering was evaluated to equip surfaces of orthodontic elastomeric ligatures with silver and bismuth nanofilms.

MATERIAL AND METHODS

Antibacterial properties were evaluated by the adhesion of Streptococcus mutans. Polyurethane-based elastomeric ligatures were coated with silver and bismuth nanofilms via direct current magnetron sputtering. Surface roughness (Ra ) and surface-free energy (SFE) were assessed. Coated specimens were incubated with S. mutans for 2 h. Adhering bacteria were visualized by Hoechst staining and quantified by an ATP-based luminescence assay. One-way analysis of variance with Tukey post hoc testing and Pearson correlation analysis were performed (p < .05) to relate bacterial adhesion to surface roughness and surface-free energy.

RESULTS

Elastomeric ligatures were successfully coated with silver and bismuth nanofilms. Ra was significantly reduced by silver coating. Silver and bismuth coatings showed significantly higher SFE than controls. Adhesion of S. mutans was significantly decreased by silver coating. No correlation between bacterial adhesion and SFE was found. Correlation between bacterial adhesion and Ra was positive but not statistically significant.

CONCLUSIONS

Magnetron sputtering proved to be a feasible method to equip orthodontic elastomeric ligatures with silver and bismuth nanofilms. Silver coatings of elastomeric ligatures may reduce white spots and carious lesions in orthodontic patients. Future research is required to stabilize coatings.

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.

In vitro study of structural and mechanical properties of latex and non-latex intermaxillary orthodontic elastics

PURPOSE

We evaluated bacterial endotoxin adhesion, superficial micromorphology and mechanical properties of latex and non-latex intermaxillary orthodontic elastics.

METHODS

To quantify the adhered bacterial endotoxin, elastics were divided into 5 groups: experimental (n = 12) latex and non-latex elastics, previously contaminated by an endotoxin solution, negative control (n = 6) latex and non-latex elastics without contamination, and positive control (n = 6) stainless steel specimens (metallic replicas), contaminated by an endotoxin solution. In parallel, the structural micromorphology (n = 6) and surface roughness of latex and non-latex intermaxillary orthodontic elastics were assessed using confocal laser microscopy. Force degradation (g) and deformation of the internal diameter change (mm) were also evaluated. Structural micromorphology, surface roughness (µm), force degradation (g) and internal diameter (mm) change were evaluated at time 0 and after 24 and 72 h in a deformation test. Data were analyzed by the Shapiro-Wilk, Kruskal-Wallis, Dunn, ANOVA and Bonferroni tests (α = 5%).

RESULTS

Endotoxin adhered similarly to both types of elastics with scores of 3 (> 1.0 EU/mL). The surface microstructure of both types of elastics showed irregularities and porosities at all times. Initially, the latex elastics had a higher surface roughness (p < 0.001) than the non-latex ones. After 24 h loading, surface roughness of the latex elastics was significantly reduced (p < 0.001), while after 72 h, the values were similar for both types (p > 0.05). The non-latex elastics had significantly higher force generation values (p < 0.05) at 0, 24 and 72 h compared with the latex elastics, although there was a significant reduction (p < 0.001) in force over time for both elastics. Despite similar initial values, non-latex elastics had a significantly larger internal diameter (p < 0.001) after the loading periods of 24 and 72 h compared with the latex elastics.

CONCLUSION

Both elastics showed high affinity with endotoxin and microstructural irregularities of their surface. The non-latex elastics generated higher force values but demonstrated greater deformation of the internal diameter after loading.

Leveling and alignment time and the periodontal status in patients with severe upper crowding treated by corticotomy-assisted self-ligating brackets in comparison with conventional or self-ligating brackets only: a 3-arm randomized controlled clinical trial

INTRODUCTION

The lengthy period of time required is one of the main reasons patients refuse orthodontic treatment. In addition, treatment may have negative effects on periodontal tissues.

OBJECTIVE

This study aimed to evaluate the overall time needed for leveling and alignment and the periodontal indices in adult patients with severe crowding. Patients were treated using either self-ligating brackets associated with flapless corticotomy (SLBs + FC group), self-ligating brackets alone (SLBs group), or conventional brackets (CBs group) alone.

MATERIALS AND METHODS

A total of 57 adult patients (10 male patients, 47 female patients) referred to the Department of Orthodontics, the University of Damascus Dental School from August 2018 to March 2019, were enrolled in this trial. The patients were randomly allocated to 1 of 3 groups: CBs (mean age: 19.62 ± 2.42 years), SLBs (mean age: 19.98 ± 2.84 years), or SLBs + FC (mean age: 20.67 ± 2.59 years). The overall alignment time for the upper anterior teeth was calculated. The following periodontal parameters were measured at 5 assessment times: plaque index, gingival index, papillary bleeding index, and probing depth.

RESULTS

The average leveling and alignment time was 81.89 ± 9.49 days, 123 ± 10.69 days, and 165.25 ± 13.05 days for the SLBs + FC group, the SLBs group, and the CBs group, respectively. A significant reduction in the overall alignment duration was found in the SLBs + FC group by 50%, and in the SLBs group by 25%, compared to the control group, with a statistically significant difference among the 3 groups (P < 0.001). There were statistically significant differences in the periodontal indices (except probing depth) after 1 month, with values greater in the SLBs + FC group (P < 0.05).

CONCLUSIONS

Using self-ligating brackets in combination with flapless corticotomy may be effective in accelerating upper dental decrowding in adult patients, with a reduction of 50% of the normal treatment time using traditional brackets. Using self-ligating brackets alone reduced treatment time by 25%. The adjunctive flapless corticotomy did not cause clinically negative effects on the periodontal tissues.

The Effect of Liquid Rubber Addition on the Physicochemical Properties, Cytotoxicity, and Ability to Inhibit Biofilm Formation of Dental Composites

The aim of this study was to evaluate the effect of modification with liquid rubber on the adhesion to tooth tissues (enamel, dentin), wettability and ability to inhibit bacterial biofilm formation of resin-based dental composites. Two commercial composites (Flow-Art–flow type with 60% ceramic filler and Boston–packable type with 78% ceramic filler; both from Arkona Laboratorium Farmakologii Stomatologicznej, Nasutów, Poland) were modified by addition of 5% by weight (of resin) of a liquid methacrylate-terminated polybutadiene. Results showed that modification of the flow type composite significantly (p < 0.05) increased the shear bond strength values by 17% for enamel and by 33% for dentine. Addition of liquid rubber significantly (p < 0.05) reduced also hydrophilicity of the dental materials since the water contact angle was increased from 81–83° to 87–89°. Interestingly, modified packable type material showed improved antibiofilm activity against Steptococcus mutans and Streptococcus sanguinis (quantitative assay with crystal violet), but also cytotoxicity against eukaryotic cells since cell viability was reduced to 37% as proven in a direct-contact WST-8 test. Introduction of the same modification to the flow type material significantly improved its antibiofilm properties (biofilm reduction by approximately 6% compared to the unmodified material, p < 0.05) without cytotoxic effects against human fibroblasts (cell viability near 100%). Thus, modified flow type composite may be considered as a candidate to be used as restorative material since it exhibits both nontoxicity and antibiofilm properties.

Comparison of microbial adhesion and biofilm formation on orthodontic wax materials; an in vitro study

Background/purpose

Orthodontic wax materials are available on the dental market and are given by orthodontists due to pain, sores and irritation caused by treatment. The aim of the study was to compare biofilm formation and microbial adhesion at different time points on different protective materials used against orthodontic wounds in vitro.

Materials and methods

Microbial adhesion and biofilm formation were evaluated against Streptococcus mutans ATCC 25175 and Lactobacillus acidophilus ATCC 4356 standard strains on orthodontic wax materials at the 0, 24th, 48th, 72nd, 96th and 120th hour. The Kruskal Wallis test and Bonferroni test were used for statistical evaluations. Statistical significance was set at p < 0.05.

Results

It was observed that S. mutans formed statistically significantly more biofilm on OrthoDots®CLEAR (OrVance) than Ora-Aid (TBM Corporation) at the 48th hour (p < 0.05). Furthermore, L. acidophilus formed statistically significantly more biofilm on OrthoDots®CLEAR (OrVance) than Brace Gard®(Infa-Lab Inc.) at the 72nd, 96th and 120th hours (p < 0.05).

Conclusion

Significant differences were noted among the different orthodontic wax materials and both S. mutans and L. acidophilus created biofilm on all waxes at different time points in vitro. To prevent biofilm formation, these waxes need to be refreshed and should not be used for more than 24 h. According to our study, biofilm production performances of pathogens on Brace Gard®(Infa-Lab Inc.) are minimal and therefore it may be a better option to use in clinics. However, to our knowledge, this is the first study investigating biofilm formation on waxes and more studies are needed in this field.

Candida prevalence and oral hygiene due to orthodontic therapy with conventional brackets

BACKGROUND

Conventional brackets are often used during orthodontic therapy of patients with malocclusion. The complex construction of such brackets greatly inhibits oral hygiene, which predisposes to increased carriage of microbiota. Orthodontic brackets could act as reservoir of yeast and predispose to oral candidosis. The aim of this study was to assess Candida prevalence and the role of oral hygiene during fixed appliance therapy. A further aim was to characterize the isolated yeasts according to their ability to form biofilms.

METHODS

Seventeen participants (average age 17 ± 7 years) were monitored by taking oral rinses and elastomeric ligature samples, and by evaluating the approximal plaque index (API) and gingival bleeding index (GBI) before and after placement of the orthodontic conventional brackets for 12 weeks. Isolated yeasts were counted and biofilm formation was evaluated.

RESULTS

One hundred and sixteen samples (67 oral rinses and 49 orthodontic elastomers) were collected. Ten patients (58.8% subjects) were Candida-carriers (two were colonized after bracket placement) and C. albicans was the most common species. The average number of yeasts in the oral cavity showed some fluctuation during the study, but in general had an upward trend (adj. R2 = 0.7967, p = 0.07025). A correlation was found between median number of yeasts and the periodontal indices (API, GBI). The average API values decreased in the Candida-carriers (adj. R² = 0.95; p = 0.01709), while average GBI values increased in the noncarriers (adj. R² = 0.92; p = 0.0256).

CONCLUSIONS

Treatment with orthodontic appliances promotes Candida yeast colonization, which is variable over time in terms of strain and species, with dominance of C. albicans, and without increased biofilm-forming activity. The API value decreases over time in carriers, and the GBI value increases in uncolonized patients, which may have predictive significance for the development of oral candidiasis during orthodontic treatment.

Evidence of variable bacterial colonization on coloured elastomeric ligatures during orthodontic treatment: An intermodular comparative study

Background

Besides, other factors, the choice of materials used as orthodontic ligatures could be one of the many tools to counter the effects of microbial adhesion, that culminates into dental ailments. Therefore, we assessed bacterial adhesion on elastomeric ligatures with special reference to coloured elastomeric rings during orthodontic treatment.

Material and Methods

A split mouth study, involving 240 samples of different elastomeric ligatures from forty orthodontic patients possessing good oral hygiene was carried out. The archwire was ligated to the brackets on both arches with elastomeric rings (superslick, clear transparent , blue and pink) at predetermined quadrants. After six weeks, ligatures from second premolars were removed and processed for bacterial enumeration using standard techniques. Bacterial counts were also determined for stimulated saliva samples taken at 0 and 6 weeks.

Results

A statistically significant difference in bacterial counts was obtained amongst different elastomeric modules used. Maximum bacterial counts were found on conventional pigmented elastomeric modules, followed by Superslick module and clear module. More number of bacteria associated with the conventional pink as compared to the conventional blue pigmented modules, however it was not statistically significant. The three bacterial genera Streptococcus Staphylococcus and Aerobic Lactobacilli adhered to elastomeric modules in following predominant pattern i.e. Conventional pink>Conventional Blue>Superslick>Clear.

Conclusions

The studies evidenced colour and material dependent bacterial colonization on orthodontic modules and could be an indicator of bacterial biofilm forming potential based on surface chemistries and a clinically efficacious tool to redesign conventional and modified elastomeric rings as orthodontic ligation accessories.

Key words:Bacterial colonization, biofilm, coloured elastomers, orthodontic ligatures.

Microbial Colonization on Elastomeric Ligatures during Orthodontic Therapeutics: An Overview

The current review focuses on the studies conducted on the colonization of microorganisms on orthodontic ligatures during orthodontic treatment. The fixed orthodontic appliances have long been associated with an increase in plaque accumulation, bacterial colonization, and resultant enamel decalcification. Voluminous research has been carried out on the microbial colonization of even newer orthodontic materials such as elastomeric ligatures with an evidence of variably increased microbial counts during orthodontic treatment. However, conclusive material-based data for minimal microbial colonization to establish acceptance criteria for the use of elastomeric ligatures are hardly available. Thus, there is a need for further studies with dual emphasis on exploring microbial associations based on surface chemistries of different elastomers and their requisite modifications for hampering microbial biofilms to evolve efficacious oral health friendly orthodontic ligatures.

Quantification of Streptococcus mutans in Different Types of Ligature Wires and Elastomeric Chains

This study aimed to test the hypothesis that Streptococcus mutans contamination levels differ according to the type of the orthodontic ligature. Thirteen patients were selected. Each quadrant was randomly subjected to one of the following ligature-use protocols: I) elastomeric chain, II) steel ligature crossed over the archwire, III) steel ligature crossed under the archwire, and IV) steel ligature in a figure-eight pattern under the archwire. After seven days, the devices were removed and the Streptococcus mutans colony-forming unit count per mg of biofilm weight was determined. Twelve specimens (n=3) were also processed for scanning electron microscopy analysis. ANOVA and Tukey-Kramer test were used for comparisons to assess S. mutans differences between groups at a 5% significance level. There was no statistical difference in detectable levels of S. mutans among the groups (p=0.294). Scanning electron microscopy results showed abundant biofilms and microbial contamination in all groups. In conclusion, S. mutans contamination levels are similar in the different orthodontic ligatures.

Biosynthesis of Silver Nanoparticles on Orthodontic Elastomeric Modules: Evaluation of Mechanical and Antibacterial Properties

In the present study, silver nanoparticles (AgNPs) were synthesized in situ on orthodontic elastomeric modules (OEM) using silver nitrate salts as metal-ion precursors and extract of the plant Hetheroteca inuloides (H. inuloides) as bioreductant via a simple and eco-friendly method. The synthesized AgNPs were characterized by UV-visible spectroscopy; scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The surface plasmon resonance peak found at 472 nm confirmed the formation of AgNPs. SEM and TEM images reveal that the particles are quasi-spherical. The EDS analysis of the AgNPs confirmed the presence of elemental silver. The antibacterial properties of OEM with AgNPs were evaluated against the clinical isolates Streptococcus mutans, Lactobacillus casei, Staphylococcus aureus and Escherichia coli using agar diffusion tests. The physical properties were evaluated by a universal testing machine. OEM with AgNPs had shown inhibition halos for all microorganisms in comparison with OEM control. Physical properties increased with respect to the control group. The results suggest the potential of the material to combat dental biofilm and in turn decrease the incidence of demineralization in dental enamel, ensuring their performance in patients with orthodontic treatment.

Biofilm formation in Haas palatal expanders with and without use of an antimicrobial agent: an in situ study

Orthodontic appliances causes specific alterations in oral environment, including reduction of pH, increase of dental biofilm and elevation of salivary microbial levels, causing an increased risk for dental caries. This study evaluated, using microbial culture and scanning electron microscopy (SEM), the in situ contamination by mutans streptococci (MS) of different surfaces of Haas palatal expanders with and without use of chlorhexidine gluconate mouthrinses (CHX). Thirty-four patients were randomly assigned to two groups (n = 17/group), using placebo (Group I) and 0.12% CHX (Group II-Periogard^® ) mouthrinses twice a week. After 4 months, appliances were submitted to microbiological processing and after fragments were analyzed by SEM. Mann-Whitney U test (α = 5%) was used to assess differences between groups on the appliances' different surfaces and to compare the contamination on the free and nonfree surfaces of these components. There was no difference (p = 0.999) between groups regarding the number of MS colonies/biofilms on the nonfree surfaces, which showed intense contamination. However, free surfaces of Group II presented less contamination (p < 0.001) than those of Group I in all appliances' components. Results of the microbial culture were confirmed by SEM. Use of 0.12% CHX was effective in reducing the formation of MS colonies/biofilms on free surfaces of Haas expanders, in situ.

Bacterial biofilm on successful and failed orthodontic mini-implants--a scanning electron microscopy study

Mini-implants have been extensively used in Orthodontics as temporary bone anchorage devices. However, early failure of mini-implants due to mobility might occur and the colonization of their surfaces by pathogenic bacteria has been referred to as one of the contributing factors. In this study, scanning electron microscopy (SEM) was used to assess the presence of microorganisms adhered to the surface of mini-implants that failed due to loss of stability. Twelve self-drilling titanium mini-implants (1.6 mm diameter × 9.0 mm long) were collected from 12 patients undergoing orthodontic treatment-7 successful and 5 failed mini-implants. The mean time of permanence in the mouth was 15.8 and 2.4 months for successful and failed mini-implants, respectively. The devices were placed in the maxilla and/or mandible and removed by the same surgeon and were processed for SEM analysis of the presence of microorganisms on their surfaces (head, transmucosal profile, and body). Extensive bacterial colonization on mini-implant head and transmucosal profile was observed in all successful and failed mini-implants. None of the failed mini-implants exhibited bacteria on its body and only one mini-implant belonging to the successful (stable) group exhibited bacteria on its body. The results did not suggest a relationship between failure and presence of bacterial colonies on mini-implant surfaces.

Latex and nonlatex orthodontic elastics: In vitro and in vivo evaluations of tissue compatibility and surface structure

Objective: 

To test the null hypothesis that there is no difference between latex and nonlatex orthodontic elastics with respect to tissue compatibility and surface structure.

Materials and Methods: 

Latex and nonlatex elastics were implanted in the subcutaneous connective tissue of 45 Wistar rats. In the control groups, no material was implanted (sham). After 24 hours, 3, 7, 14, and 21 days, the animals were euthanized; tissue samples were processed and analyzed by descriptive and semi-quantitative microscopic analysis and quantification of plasma extravasation. The surface structure of elastics was evaluated by scanning electron microscopy (SEM). The results were analyzed by analysis of variance (ANOVA), Tukey test and Kruskal-Wallis test at 5% significance level.

Results: 

Peri-implant plasma extravasation was significantly higher (P &lt; .05) in the animals that received latex elastics compared with those with nonlatex elastics and those that were control animals. The microscopic analysis revealed a more intense inflammatory infiltrate in the initial periods without statistically significant difference (P &gt; .05) between the experimental and control groups. The SEM analysis revealed that the latex elastics presented microspheres and porosities, while the nonlatex elastics exhibited crystals on their surface and absence of porosities.

Conclusion: 

The null hypothesis was rejected since the latex elastics were more irritating to the connective tissue than the nonlatex elastics in the initial periods and presented a more porous surface.

Orthodontic bracket designs and their impact on microbial profile and periodontal disease: A clinical trial

Aim:

The aim of the present study was to compare the undisturbed plaque formation on teeth bonded with Preadjusted (Captain Ortho, Libral Traders, Mumbai, India) and Begg Brackets (Captain Ortho, Libral Traders, Mumbai, India) with nonbonded control sites via a de novo plaque growth over a period of 7 days.

Materials and Methods:

A clinical trial with the split-mouth design was set up enrolling 10 dental students. Within each subject sites with (Preadjusted) (P-site), Begg brackets (B-site) and control sites were followed. Plaque index and gingival index were recorded on days 3 and 7. Supra-gingival and sub-gingival plaque samples were taken from the brackets and the teeth on days 3 and 7, and were sent for aerobic and anaerobic culturing. The total number of bacterial colony forming units (CFU) was assessed for each sample using a colony counter. Tukeys and Dunnett test then statistically analyzed data.

Results:

The mean plaque index and gingival index increased on P-site and B-site on the third and 7^th day. The shift from aerobic to anaerobic species was observed earlier in P-sites than in B-sites. The CFU were significantly higher for all sites on day 7 when compared with day 3. The aerobe/anaerobe CFU ratio was significantly lower in P-sites than in B-sites and then control showing an increase in the number of anaerobic species on the 3^rd and 7^th day (P < 0.05). Based on observed means, the mean difference was significant (P < 0.05).

Conclusion:

The present data suggest that Preadjusted brackets accumulated more plaque than Begg brackets. Bracket design can have a significant impact on bacterial load and on periodontal parameters.

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.

Antibacterial efficacy of prophylactic ozone treatment on patients with fixed orthodontic appliances

OBJECTIVE

This study investigated the efficacy of ozone on microflora of patients with fixed orthodontic appliances.

MATERIALS AND METHODS

Ten subjects undergoing fixed appliance therapy were enrolled in the study. Before any application, two elastic ligatures were removed with the aid of a sterile probe from the premolar brackets on the upper right and lower left jaws for baseline bacteriological counts. Then ozone gas was applied for 180 s by running the device on prophylaxis mode with included mouth tray according to the manufacturer's recommendations on all brackets. After the ozone application, two other elastic ligatures were removed from the opposite sides of the mouth of the patients. One week after the application two more elastic samples, which were not changed in the previous session, were collected from the upper right and lower left premolar brackets. The elastic ligatures were immersed in transfer solutions and cultured to determine the Streptococcus mutans and Lactobacillus acidophilus. Statistical analysis of the data was obtained by paired Student's t-tests.

RESULTS

The ozone treatment reduced the S. mutans and L. acidophilus immediately after the application and these reductions were found to be statistically significant (p = 0.038 and p = 0.020). Both the S. mutans and L. acidophilus values increased by the 1-week period and the S. mutans values were significantly higher than the baseline values (p = 0.01).

CONCLUSION

It can be concluded that the ozone treatment may have an instantaneous lethal effect on S. mutans and L. acidophilus; however, within the limitations of this study, a long-term preventive effect could not be observed.

In situ evaluation of orthodontic elastomeric chains

The hypothesis tested in this study was that intraoral exposure of elastomeric chains alters their tensile strength. For such purpose, it was evaluated the in situ behavior of different elastomeric chains stretched for 3 weeks. Three kinds of elastomeric chains, Plastic chain (PC), Memory chain (MC) and Super slick chain (SSC), were randomly placed in 3 quadrants of 13 patient in a fixed distance of 16 mm and mean initial force of 180 g. Tensile testing was performed in an universal testing machine at different intervals: initial, 1 h, 24 h, 1 week, 2 weeks and 3 weeks. A two-way ANOVA test was performed to identify the influence of both material and time on the force decrease. A subsequent one-way ANOVAtest with the Tukey's post hoc test was used to identify statistically significant intragroup and intergroup remaining force (g and %) differences at 5% significance level. The effect of both the material and the time factors were significant. All groups showed significant force decrease after the 1-h period (23% for PC and 14% for MC and SSC). At the end of the 3-week period, the remaining force was 57% (96 g), 67% (129 g) and 71% (125 g) for PC, MC and SSC, respectively. In conclusion, intraoral exposure of elastomeric chains altered their tensile strength. In general, the greater force decrease occurred within the first hour. The remaining force of the enhanced chains measured at each time interval was greater than the conventional one (PC). After 3 weeks, only the enhanced chains maintained the force applied over 100 g.

Corrosion in Haas expanders with and without use of an antimicrobial agent: an in situ study

Objectives

The purpose of this study was to evaluate in situ the occurrence of corrosion in the soldering point areas between the wire, silver brazing and band in Haas expanders.

Material and Methods

Thirty-four 7-12-year-old patients who needed maxillary expansion with a Haas expander were randomly assigned to two groups of 17 individuals each, according to the oral hygiene protocol adopted during the orthodontic treatment: Group I (control), toothbrushing with a fluoride dentifrice and Group II (experimental), toothbrushing with the same dentifrice plus 0.12% chlorhexidine gluconate (Periogard^®) mouthrinses twice a week. The appliances were removed after approximately 4 months. Fragments of the appliances containing a metallic band with a soldered wire were sectioned at random for examination by stereomicroscopy, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Data were analyzed statistically by Fisher's test at 5% significance level.

Results

The analysis by optical microscopy revealed areas with color change suggestive of corrosion in the soldering point areas joining the band and the wire in all specimens of both groups, with no statistically significant difference between the groups (p=1). The peaks of chemical elements (Ni, Fe, Cr, O, C and P) revealed by EDS were also similar in both groups.

Conclusion:

Color changes and peaks of chemical elements suggestive of corrosion were observed in the soldering point areas between the wire, silver brazing and band in both control and experimental groups, which indicate that the 0.12% chlorhexidine gluconate mouthrinses did not influence the occurrence of corrosion in situ.

The effect of silver ion-releasing elastomers on mutans streptococci in dental plaque

Objective

The purpose of this study was to investigate the antimicrobial effect of silverized elastomers on mutans streptococci in dental plaque.

Methods

Forty patients undergoing orthodontic treatment were randomly placed into 1 of 2 groups. We examined the maxillary right and left central incisors and premolars, and the mandibular right and left canines of all participants. We ligated the right maxillary and left mandibular teeth of the participants in group 1 with silverized elastomers and ligated their contralateral teeth with conventional elastomers. We ligated the left maxillary teeth and right mandibular teeth of group 2 participants with silverized elastomers. Each participant visited the clinic 4 times at 3-week intervals. We applied the elastomers to the teeth on one side of each patient's mouth during their first visit. During the second visit, the elastomers were removed for microbiological analysis and replaced with steel ligatures. During the third visit, we used silverized elastomers to ligate the teeth contralateral to those treated on the first visit. The elastomers were removed during the fourth visit, and microbiological analyses were performed. We compared the quantity of bacteria on silverized and conventional elastomers at the 0.05 level of significance.

Results

The percentage of mutans streptococci was not significantly different in cultures of dental plaque from the silverized and the conventional elastomers (p > 0.05).

Conclusions

There was no significant difference between the antimicrobial effect of the silverized elastomers and that of the conventional elastomers.

Molecular detection of in-vivo microbial contamination of metallic orthodontic brackets by checkerboard DNA-DNA hybridization

INTRODUCTION

Knowing the microbiota that colonizes orthodontic appliances is important for planning strategies and implementing specific preventive measures during treatment. The purpose of this clinical trial was to evaluate in vivo the contamination of metallic orthodontic brackets with 40 DNA probes for different bacterial species by using the checkerboard DNA-DNA hybridization (CDDH) technique.

METHODS

Eighteen patients, 11 to 29 years of age having fixed orthodontic treatment, were enrolled in the study. Each subject had 2 new metallic brackets bonded to different premolars in a randomized manner. After 30 days, the brackets were removed and processed for analysis by CDDH. Data on bacterial contamination were analyzed descriptively and with the Kruskal-Wallis and Dunn post tests (α = 0.05). Forty microbial species (cariogenic microorganisms, bacteria of the purple, yellow, green, orange complexes, "red complex +Treponema socranskii," and the cluster of Actinomyces) were assessed.

RESULTS

Most bacterial species were present in all subjects, except for Streptococcus constellatus, Campylobacter rectus, Tannerella forsythia, T socranskii, and Lactobacillus acidophillus (94.4%), Propionibacterium acnes I and Eubacterium nodatum (88.9%), and Treponema denticola (77.8%). Among the cariogenic microorganisms, Streptococcus mutans and Streptococcus sobrinus were found in larger numbers than L acidophillus and Lactobacillus casei (P <0.001). The periodontal pathogens of the orange complex were detected in larger numbers than those of the "red complex +T socranskii" (P <0.0001). Among the bacteria not associated with specific pathologies, Veillonella parvula (purple complex) was the most frequently detected strain (P <0.0001). The numbers of yellow and green complex bacteria and the cluster of Actinomyces were similar (P >0.05).

CONCLUSIONS

Metallic brackets in use for 1 month were multi-colonized by several bacterial species, including cariogenic microorganisms and periodontal pathogens, reinforcing the need for meticulous oral hygiene and additional preventive measures to maintain oral health in orthodontic 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.

Influence of cigarette smoke condensate on cariogenic and candidal biofilm formation on orthodontic materials

INTRODUCTION

An experimental analysis was made to quantify the adherence rates and the biofilm formation capacity of Streptococcus mutans ATCC25175 and Candida albicans SC5314 on orthodontic material surfaces in the presence of cigarette smoke condensate (CSC).

METHODS

Metal brackets, bands, acrylic resin, and polyurethane elastic rings were coated with stimulated saliva and submitted to adhesion and biofilm formation tests with and without CSC in a dynamic system.

RESULTS

The CSC increased the adhesion of S mutans ATCC25175 to the acquired pellicle (P <0.05) for bands (4.08 times), acrylic resin (2.89 times), and brackets (3.37 times) and reduced it in polyurethane elastic (2.66 times; P <0.05). S mutans ATCC25175 biofilm biomass was increased by CSC only on brackets (1.60 times; P <0.05). In the presence of CSC, the adhesion of C albicans SC5314 increased (P <0.05) on bands (1.81 times), brackets (9.61 times), elastics (29,133 times), and acrylic resin (177 times). Greater formation of C albicans SC5314 biofilm caused by CSC (P <0.05) was observed on acrylic resin (2.13 times) and brackets (2.32 times).

CONCLUSIONS

The results indicated that cigarette tobacco smoke can interfere with the adhesion and biofilm formation of these microorganisms to various orthodontic materials.