Does the Seating Force Affect the Shear Bond Strength of Brackets? An InVitro Study

Area of Science:

• Orthodontics
• Biomaterials Science
• Dental Materials

Background:

• Orthodontic bracket debonding is a common clinical concern.
• Understanding factors influencing bracket bond strength is crucial for treatment success.
• Shear bond strength (SBS) is a key metric for evaluating bracket adhesion.

Purpose of the Study:

• To evaluate the effect of two different seating forces (100g and 200g) on the shear bond strength (SBS) of conventional and self-ligating orthodontic brackets.
• To compare the SBS between conventional and self-ligating bracket systems under varying seating forces.

Main Methods:

• Forty-eight human premolars were divided into four groups, testing conventional and self-ligating brackets with 100g and 200g seating forces.
• All brackets were bonded using Transbond XT adhesive.
• Teeth were stored in deionized water, thermal cycled, and subjected to SBS testing using a universal testing machine.

Main Results:

• Mean SBS values were 15.70 MPa (conventional, 100g), 13.97 MPa (conventional, 200g), 8.38 MPa (self-ligating, 100g), and 8.31 MPa (self-ligating, 200g).
• Significant differences in SBS were found between conventional and self-ligating bracket groups.
• Seating forces (100g vs. 200g) did not demonstrate significant differences in SBS within either bracket type.

Conclusions:

• Both 100g and 200g seating forces yield acceptable shear bond strength for both conventional and self-ligating brackets.
• Clinicians can apply these seating forces with confidence, as they do not compromise bond integrity within the tested parameters.