Optimal enamel conditioning strategy for rebonding orthodontic brackets: a laboratory study

Area of Science:

• Orthodontics
• Dental Materials Science
• Adhesive Dentistry

Background:

• Bracket rebonding is a common procedure in orthodontics.
• Evaluating different adhesive methods is crucial for clinical success.
• Conventional etching and primer (CEP) and self-etching primer (SEP) methods are widely used.

Purpose of the Study:

• To compare the efficacy of CEP and SEP methods for rebonding orthodontic brackets.
• To assess the shear bond strength (SBS) and adhesive remnant index (ARI) of rebonded brackets.

Main Methods:

• Forty human premolars were divided into four groups.
• Groups 1 and 2 used CEP; Groups 3 and 4 used SEP.
• Brackets were rebonded using different protocols, including omission of the acid-etching step in some groups.
• Shear bond strength (SBS), adhesive remnant index (ARI), and SEM examination were performed.

Main Results:

• Mean SBS for Group 1 (CEP) was 14.18 MPa; Group 2 (CEP without etch) was 6.57 MPa.
• Mean SBS for Group 3 (SEP) was 11.90 MPa; Group 4 (non-acidic primer) was 5.91 MPa.
• Significant differences in SBS were found between Group 1 and 2, and between Group 3 and 4 (P < 0.05).
• No significant difference in SBS was observed between Group 1 and 3, or between Group 2 and 4.

Conclusions:

• Omitting the acid-etching step in the CEP method may be clinically adequate for rebonding.
• Both CEP and SEP methods demonstrated comparable SBS and ARI when used with their respective primers.
• The findings suggest flexibility in choosing between CEP and SEP for bracket rebonding.