Microstructural and mechanical characterization of contemporary lingual orthodontic brackets

Area of Science:

• Materials Science
• Biomaterials Engineering
• Orthodontics

Background:

• Lingual brackets offer aesthetic advantages in orthodontic treatment.
• Understanding their material properties is crucial for clinical efficacy.
• Variations in composition and microstructure can impact mechanical performance.

Purpose of the Study:

• To compare the elemental composition, microstructure, and mechanical properties of three lingual bracket systems.
• To identify differences between Incognito, In-Ovation L, and STb lingual brackets.

Main Methods:

• Scanning electron microscopy (SEM) with energy-dispersive X-ray microanalysis (EDX) for composition.
• Vickers hardness and instrumented indentation tests for mechanical properties.
• Statistical analysis using two-way ANOVA and post hoc tests.

Main Results:

• Incognito brackets, primarily noble metal, showed a single phase. In-Ovation L and STb brackets, ferrous alloys, exhibited distinct phases.
• No significant hardness or modulus differences were found between ferrous brackets, but variations existed between base and wing regions.
• Incognito brackets displayed intermediate mechanical values compared to the ferrous brackets.

Conclusions:

• Significant variations in microstructure, elemental composition, and mechanical properties exist among the tested lingual bracket systems.
• These material differences may influence clinical outcomes during orthodontic mechanotherapy.
• Further research is warranted to correlate these properties with clinical performance.