Recycling effects on ceramic brackets: a dimensional, weight and shear bond strength analysis

Area of Science:

• Materials Science
• Biomaterials Engineering
• Orthodontics

Background:

• Orthodontic ceramic brackets are widely used for their aesthetic properties.
• The cost-effectiveness and environmental impact of dental materials are growing concerns.
• Investigating recycling techniques for orthodontic materials can reduce waste and costs.

Purpose of the Study:

• To evaluate the effects of a recycling technique on the physical properties and bond strength of orthodontic ceramic brackets.
• To determine the clinical relevance of dimensional and weight changes in recycled brackets.
• To assess the safety of using recycled ceramic brackets concerning enamel integrity.

Main Methods:

• Scanning electron microscopy (SEM) analysis was employed to examine bracket morphology.
• Weight and dimensional changes (slot width, depth, base area) were measured after 1, 5, and 10 recycling cycles.
• Shear bond strength testing was performed on new and recycled brackets.
• Analysis of bond failure modes was conducted to assess enamel damage.

Main Results:

• Dimensional and weight changes in recycled brackets were minimal and deemed clinically insignificant.
• Mean shear bond strengths for new brackets were 15.52 MPa, decreasing slightly but remaining adequate after recycling (11.23 MPa after 1 cycle, 10.10 MPa after 5 cycles, 10.04 MPa after 10 cycles).
• Recycled brackets exhibited bond failures primarily at the bracket/adhesive interface, preserving enamel structure.

Conclusions:

• Recycling orthodontic ceramic brackets is a viable technique that preserves essential mechanical properties.
• Recycled ceramic brackets demonstrate sufficient shear bond strength for clinical application.
• The recycling process does not compromise enamel integrity during debonding, making it a safe and potentially cost-effective alternative.