In vitro evaluation of microbial contamination and the disinfecting efficacy of chlorhexidine on orthodontic brackets

Sterilizing orthodontic appliances: A systematic review and meta-analysis on the available methods

Infection control is essential to protect both the doctor and the patient by preventing the spread of infectious diseases. There is no exception in the field of dentistry, particularly in orthodontics, where numerous appliances are used for a variety of functions and also because the mouth cavity has the highest concentration of bacteria of any body part. Through this systematic review, we aimed to assess the various methods of sterilization employed in an orthodontic setting. Using relevant keywords, reference searches, and citation searches, the databases such as PubMed, MEDLINE, Web of Science, Cochrane, and Scopus were all searched; a total of 206 documents were found, of which 113 were initially selected. The remaining 23 distinct papers were initially made available after 90 publications that were identical to or similar to one another were eliminated. The final selection was made from eight documents that met all inclusion and exclusion requirements. The existing methods of sterilization were found to be competent in dealing with the microorganisms found in a typical orthodontic setting. The chemical method of sterilization was the norm in most of the studies that we assessed, with glutaraldehyde and peracetic acid (PAA) being the most commonly employed compounds for disinfection. PROSPERO Registration Number: CRD42022380831.

Comparative evaluation of different debonding and reconditioning methods for orthodontic ceramic brackets regarding effectiveness for reuse : An in vitro study

PURPOSE

To investigate the reusability of ceramic brackets in terms of shear bond strength, friction behavior, slot dimension, fracture strength, and color stability.

METHODS

A total of 90 conventionally debonded and 30 by an Er:YAG laser debonded ceramic brackets were collected. All the used brackets were inspected under a stereomicroscope at 18 × magnification and sorted according to their adhesive remnant index (ARI). Five groups were formed (n = 10): (1) new brackets as a control group, (2) flamed and sandblasted, (3) flamed and acid bathed, (4) laser-reconditioned, and (5) laser-debonded brackets. The bracket groups were tested regarding different properties such as shear bond strength, friction behavior, slot size, fracture strength, and color stability. Analysis of variance (ANOVA) and nonparametric Kruskal-Wallis tests were used for statistical analysis (significance level: p < 0.05).

RESULTS

Shear bond strength values of the acid reconditioned brackets were significantly lower (8.0 ± 3.1 MPa) compared to the control group (12.9 ± 2.9 MPa). Laser-reconditioned (32.8 ± 2.7%) and laser-debonded (30.9 ± 2.4%) brackets showed the lowest force loss due to friction (control group 38.3 ± 3.0%). No significant differences were observed between groups regarding slot size and fracture strength. All groups had color differences of [Formula: see text]< 10. Scanning electron microscope images and ARI scores indicated that most of the residues on the bracket bases were removed.

CONCLUSION

All reconditioning methods yielded adequate results regarding bracket properties. Yet, focusing on the need to protect the enamel and the bracket base, laser debonding seems to be the most suitable method for reconditioning ceramic brackets.

Effectiveness of Different Sterilization Methods on Clinical Orthodontic Materials

Background

Orthodontic appliances such as wires and brackets received from manufacturers come unsterilized and may be contaminated with various microorganisms before being used in the mouth. In this study, we evaluated and identified the bacterial contamination on orthodontic appliances along with the disinfecting efficacy of ultraviolet (UV) light and various sterilization methods.

Methods

Different orthodontic appliances were obtained from manufacturers divided into 5 sterilization methods and a control group (control, UV, dry heat and steam autoclave, ethyl alcohol, and 2% glutaraldehyde). Microbiological and DNA sequencing was performed on the appliances to identify the contaminated bacteria.

Results

Bacterial contamination identified on the orthodontic appliances were Staphylococcus aureus, Staphylococcus epidermidis, Lactobacilli, Klebsiella pneumoniae, Bacillus licheniformis, and Bacillus cereus. UV sterilization method effectively prevented the bacterial growth when compared to the control (unsterilized) orthodontic appliances.

Conclusion

We concluded that the orthodontic appliances received from the manufacturer showed bacterial contamination. All of the tested sterilization methods including UV light were effective in eliminating the bacterial contamination on the orthodontic appliances. Since UV light does not cause change in material properties and is cost effective with relative ease of use, its use in clinical practice for the disinfection of orthodontic appliances is suggested before placement in the mouth.

Bacterial Exposure to Nickel: Influence on Adhesion and Biofilm Formation on Orthodontic Archwires and Sensitivity to Antimicrobial Agents

The presence of nickel could modify bacterial behavior and susceptibility to antimicrobial agents. Adhesion and biofilm formation on orthodontic archwires can be a source of bacterial colonization and possible health hazards. Staphylococcus aureus was subjected to exposure and adaptation to various sub-inhibitory concentrations of nickel. Five strains of bacteria adapted to nickel in concentrations of 62.5-1000 μg/mL were tested for adhesion and biofilm formation on nickel-titanium archwires. Archwires were previously incubated in artificial saliva. Bacteria were incubated with orthodontic wire with stirring for 4 h (adhesion) and 24 h (biofilm formation). The number of adherent bacteria was determined after sonication and cultivation on the Muller-Hinton agar. Disk diffusion method was performed on all bacteria to assess the differences in antimicrobial susceptibility. Bacteria adapted to lower concentrations of nickel adhered better to nickel-titanium than strains adapted to higher concentrations of nickel (p < 0.05). Biofilm formation was highest in strains adapted to 250 and 500 μg/mL of nickel (p < 0.05). The highest biofilm biomass was measured for strains adapted to 250 μg/mL, followed by those adapted to 1000 μg/mL. Bacteria adapted to lower concentrations of nickel demonstrated lower inhibition zone diameters in the disk diffusion method (p < 0.05), indicating increased antimicrobial resistance. In conclusion, bacteria adapted to 250 μg/mL of nickel ions adhered better, demonstrated higher biofilm formation and often had higher antimicrobial resistance than other adapted and non-adapted strains.

[Prevention of complications in patients with cleft lip and palate combined with teeth crowding receiving long-term orthodontic treatment]

This study aim was to improve the effectiveness of treatment of patients with cleft lip and palate in combination with crowding of teeth receiving long-term orthodontic treatment. The study involved 30 patients divided in 3 groups in which chlorhexidine-containing medication was included in the individual prevention and treatment program. The effectiveness of using 0.2% CG gel was assessed after 6 months to control the development of inflammatory phenomena in periodontal tissues during long-term orthodontic treatment. The obtained clinical and laboratory data indicate the normalization of the cytokine profile and oral hygiene indices as a result of using a CG-containing preparation for effective control of the biofilm etiological factor.

Can the chlorhexidine gluconate solution potentiate the staining of polycrystalline ceramic brackets?

Aim: The present study aimed to assess, in vitro, the effect of chlorhexidine on the potentiation of polycrystalline ceramic bracket staining. Methods: Seventy-two polycrystalline ceramic brackets of upper right central incisors were divided into six groups (n=12) according to immersion solution. The groups were G1 - distilled water (control); G2 - chlorhexidine; G3 - coffee; G4 - red wine; G5 - chlorhexidine associated with coffee; and G6 - chlorhexidine associated with red wine. The samples were analyzed by means of a spectrophotometer according to the CIEL*a*b* system, and color change (ΔE*) was calculated. The readings were performed at the following times: T0 - After package removal and T1 - After staining. The data were analyzed by Kruskal Wallis and t tests (p<0.05) at 5% significance level. Results: The total color variation (ΔE*) was greater in the group that received chlorhexidine associated with red wine (p<0.05) and lower in the groups that received distilled water. All other groups showed greater value variations when compared to G1 and G2. Group G6 showed a greater color change due to the potentiation of chlorhexidine with the dye substance. Conclusion: It is concluded that chlorhexidine potentiates the staining caused by red wine in polycrystalline ceramic brackets.