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A comparison of bond strength between direct- and indirect-bonding methods
Brandon James Linn1, David W Berzins, Virendra B Dhuru
1Castle Rock, Colo, USA.
The Angle Orthodontist
|March 17, 2006
Summary
This study compared indirect and direct bracket bonding methods. No significant differences in shear bond strength were found, but one indirect method showed fewer bond failures, indicating its potential for orthodontic treatment.
Area of Science:
- Orthodontics
- Biomaterials Science
- Dental Materials
Background:
- Indirect bonding offers potential advantages in bracket placement accuracy and efficiency.
- Evaluating the bond strength and failure modes of different indirect bonding materials is crucial for clinical application.
- Understanding material performance under physiological forces ensures treatment predictability.
Purpose of the Study:
- To compare the shear bond strength (SBS) of orthodontic brackets bonded using two indirect-bonding protocols versus a direct-bonding technique.
- To analyze the sites of bond failure (Adhesive Remnant Index - ARI) for each bonding method.
- To assess the reliability and survival rate of bonds under simulated clinical forces.
Main Methods:
- Sixty extracted human premolars were randomly assigned to three groups: direct bonding (Transbond XT), indirect bonding with chemical-cured primer (Sondhi Rapid Set) and light-cured adhesive (Transbond XT), and indirect bonding with light-cured primer (Orthosolo) and adhesive (Enlight LV).
- Shear bond strength was measured after 40 hours.
- Adhesive Remnant Index (ARI) scores were evaluated, and Weibull analysis determined bond survival rates.
Main Results:
- Mean shear bond strengths were 16.27 MPa (direct), 13.83 MPa (indirect group 2), and 14.76 MPa (indirect group 3), with no statistically significant differences between groups (P = .21).
- Weibull analysis indicated all groups achieved over 90% bond survival at normal masticatory and orthodontic force levels.
- Group 2 (chemical-cured primer, light-cured adhesive) exhibited a significantly lower ARI score (P < .05) compared to direct bonding and the other indirect group, suggesting less adhesive remnant on the tooth surface.
Conclusions:
- Both indirect bonding protocols provide comparable shear bond strength to direct bonding.
- The indirect bonding protocol using a chemical-cured primer and light-cured adhesive (Group 2) may offer an advantage by leaving less adhesive on the tooth after debonding.
- All tested bonding systems demonstrate sufficient bond strength and reliability for clinical orthodontic use.
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