Microbial contamination of orthodontic buccal tubes from manufacturers

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.

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.

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

BACKGROUND

Contamination of orthodontic appliances is due to the unhygienic practices followed during manufacturing and packaging processes, which may lead to cross-contamination. Although literature has indicated the need for sterilization or disinfection of orthodontic appliances before using in the oral cavity, this is still not employed in routine clinical practice. In this view, the current study evaluates the bacterial load on orthodontic brackets along with the disinfecting efficacy of chlorhexidine.

METHODS

A total of 140 brackets were obtained from four different manufacturers and divided into six groups: group 1 (American Orthodontics; n = 30), group 2 (3M Unitek; n = 30), group 3 (Ortho Organizers; n = 30), group 4 (China Dental Orthodontic; n = 30), group 5 (negative control; n = 10), and group 6 (positive control; n = 10). Various microbiological and biochemical tests were conducted on the brackets to detect the type and growth of bacteria. Brackets that showed microbial contamination were then subjected to disinfection using 0.01% and 2% chlorhexidine solutions.

RESULTS

Microbial contamination was detected on brackets of all the four groups. Bacteria, including Staphylococcus aureus, S. epidermidis, Lactobacilli, Klebsiella pneumoniae, Bacillus licheniformis, and B. cereus, were identified in these groups. Upon disinfection with 0.01% chlorhexidine solution, brackets in group 2 displayed complete decontamination, while all brackets in the other groups containing gram-negative bacteria exhibited complete decontamination with 2% chlorhexidine.

CONCLUSION

Orthodontic brackets received from four manufacturers showed high bacterial contamination. Disinfecting ability of 2% chlorhexidine proved highly effective in destroying both gram-positive and gram-negative bacteria. Therefore, use of 2% chlorhexidine in clinical practice for the disinfection of orthodontic brackets is suggested, before placement in the oral cavity.

In vitro evaluation of microbial contamination of orthodontic brackets as received from the manufacturer using microbiological and molecular tests

OBJECTIVE

To test the null hypothesis that orthodontic brackets as supplied by manufacturers do not have microbial contamination.

MATERIALS AND METHODS

The sample comprised 140 brackets of four different commercially available brands, used directly from the manufacturer's packaging, divided into 14 groups (n  =  10 brackets each). Of the 140 pieces, 60 were full cases and 80 were replacement brackets. Materials were tested to detect bacterial growth, analyze types of bacteria present (biochemical test), and identify bacteria (molecular test with polymerase chain reaction [PCR]).

RESULTS

In two of 12 groups the brackets showed microbial contamination: group 1, Morelli full case brackets, and group 12, Abzil-3M Unitek replacement brackets. Staphylococcus aureus and Staphylococcus epidermidis were the bacteria identified in groups 1 and 12, respectively (suggested by the biochemical test and confirmed by PCR).

CONCLUSIONS

Brackets of two brands (Morelli and Abzil-3M Unitek) were found to be contaminated by bacteria in the original packages supplied by the manufacturers, which suggests a risk for patient contamination. These data suggest that the manufacturers of these materials should improve the quality control of the packaging used, including sterilization, for the security of patient health.

N-acyl homoserine lactone-producing Pseudomonas putida strain T2-2 from human tongue surface

Bacterial cell-to-cell communication (quorum sensing) refers to the regulation of bacterial gene expression in response to changes in microbial population density. Quorum sensing bacteria produce, release and respond to chemical signal molecules called autoinducers. Bacteria use two types of autoinducers, namely autoinducer-1 (AI-1) and autoinducer-2 (AI-2) where the former are N-acylhomoserine lactones and the latter is a product of the luxS gene. Most of the reported literatures show that the majority of oral bacteria use AI-2 for quorum sensing but rarely the AI-1 system. Here we report the isolation of Pseudomonas putida strain T2-2 from the oral cavity. Using high resolution mass spectrometry, it is shown that this isolate produced N-octanoylhomoserine lactone (C8-HSL) and N-dodecanoylhomoserine lactone (C12-HSL) molecules. This is the first report of the finding of quorum sensing of P. putida strain T2-2 isolated from the human tongue surface and their quorum sensing molecules were identified.

Long chain N-acyl homoserine lactone production by Enterobacter sp. isolated from human tongue surfaces

We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4), suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL). To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium.