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Bond strength with various etching times on young permanent teeth
1School of Dentistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
Summary
A 15-second enamel etching time with phosphoric acid is recommended for orthodontic bracket bonding in teenagers. Shorter etching times ensure effective bond strength, minimize enamel loss, and reduce chairside time.
Area of Science:
- Orthodontics
- Dental Materials Science
- Adhesive Dentistry
Background:
- Orthodontic bracket debonding can lead to enamel damage and increased treatment time.
- Optimizing enamel etching protocols is crucial for achieving reliable bracket retention while minimizing iatrogenic effects.
Purpose of the Study:
- To evaluate the effect of varying enamel etching times (15, 30, 60, 90, 120 seconds) using 37% phosphoric acid on the tensile bond strength of orthodontic resin cement.
- To analyze bond failure modes and their distribution across different etching durations.
Main Methods:
- Fifty young permanent premolars were etched for specified durations and bonded with orthodontic composite resin and brackets.
- Tensile bond strength was measured using an Instron machine.
- Bond failure interfaces were examined using scanning electron microscopy and energy-dispersive x-ray spectrometry.
Main Results:
- No significant difference in tensile bond strength was observed between 15-, 30-, 60-, and 90-second etching times.
- A significant decrease in bond strength was noted at 120-second etching time.
- Cohesive failure within the resin was significantly lower at 120-second etching.
- Failure modes were predominantly between bracket-resin and resin-enamel interfaces, with no significant difference in distribution across etching times.
Conclusions:
- A 15-second enamel etching time is sufficient for optimal orthodontic bracket bonding in teenage patients.
- This shorter duration promotes adequate retention, reduces enamel loss, minimizes moisture contamination, and saves clinical chairside time.