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Endotoxin affinity for orthodontic brackets
K L Knoernschild1, H M Rogers, C A Lefebvre
1Associate Professor and Codirector of Advanced Prosthodontics, Department of Restorative Dentistry, University of Illinois at Chicago, 60612-7212, USA.
Summary
Lipopolysaccharide (LPS) from bacteria strongly adheres to orthodontic brackets, especially stainless steel and those exposed to Porphyromonas gingivalis. This bacterial endotoxin may contribute to gum inflammation near brackets.
Area of Science:
- Oral biology
- Biomaterials science
- Periodontology
Background:
- Endotoxin, or lipopolysaccharide (LPS), from gram-negative bacteria triggers immune responses and can impair periodontal tissue healing.
- Previous research indicates LPS affinity for restorative dental materials.
- Orthodontic brackets may serve as reservoirs for LPS, potentially influencing the local inflammatory environment.
Purpose of the Study:
- To investigate the adherence and elution characteristics of lipopolysaccharide (LPS) from common orthodontic bracket materials.
- To compare the affinity of LPS from Porphyromonas gingivalis and Escherichia coli for stainless steel, ceramic, plastic, and gold brackets.
Main Methods:
- Commercially available orthodontic brackets (stainless steel, ceramic, plastic, gold) were incubated with radiolabeled LPS from P. gingivalis or E. coli.
- LPS adherence was quantified after initial incubation.
- LPS elution was measured over 96 hours through serial incubation in LPS-free water and liquid scintillation spectrometry.
Main Results:
- Significant LPS adherence was observed across all bracket types, with P. gingivalis LPS showing higher adherence than E. coli LPS.
- Stainless steel brackets demonstrated the highest LPS adherence for both bacterial types.
- Measurable LPS elution occurred from ceramic and plastic brackets (24h) and stainless steel and ceramic brackets (48h) with P. gingivalis LPS.
Conclusions:
- Orthodontic brackets, particularly stainless steel, exhibit a strong affinity for bacterial LPS.
- The adherence and potential elution of LPS from brackets may influence the concentration of endotoxins in the gingival sulcus.
- This interaction could exacerbate inflammation in periodontal tissues adjacent to orthodontic appliances.
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