Bond Strength and Surface Roughness of Two Ceramics After Metal Bracket Debonding

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Orthodontic Technology

Background:

• Assessing the bond strength between orthodontic brackets and ceramic materials is crucial for treatment success.
• Understanding ceramic surface properties after debonding influences material selection and clinical protocols.

Purpose of the Study:

• To compare the shear bond strength of metallic brackets bonded to lithium disilicate and resin-matrix ceramics.
• To evaluate the impact of finishing protocols on ceramic surface roughness after adhesive removal.

Main Methods:

• Shear bond strength testing of metallic brackets bonded to treated lithium disilicate and resin-matrix ceramic samples.
• Surface roughness measurements (initial, intermediate, final) after adhesive debonding using diamond or 24-blade burs.

Main Results:

• Resin-matrix ceramics exhibited significantly higher bond strength compared to lithium disilicate.
• Rotary instruments did not alter ceramic surface roughness, but intermediate roughness was highest.
• Polishing restored resin-matrix ceramic surface roughness to initial levels, though bur use caused visible surface alterations.

Conclusions:

• Metallic brackets demonstrate superior bond strength when bonded to resin-matrix ceramics versus lithium disilicate.
• Diamond burs are recommended for debonding to minimize surface alterations on resin-matrix ceramics.