Shear bond strength of moisture-insensitive and self-etching primers under contaminated and uncontaminated conditions
An in vitro comparative study
Background: The bonding procedure in orthodontics is an important aspect that leads to a successful outcome of the treatment. Traditionally the bonding procedure demands for the least contaminated field. This procedure is technically sensitive due to the presence of various contaminants in the operative field such as moisture and saliva. Various bonding materials have evolved to overcome the difficulties in the bonding procedures such as the Moisture-Insensitive Primer (MIP) and Self-Etching Primer (SEP) with orthodontic adhesives, Composite and Resin modified glass ionomer cement (RMGIC). The shear bond strengths of these materials were examined in our study.
Materials & Methods: Fresh extracted 80 human premolars were collected and divided equally into 8 groups of 10 teeth each, and brackets were bonded with composite and RMGIC under different experimental conditions such as groups (1) etch/dry/MIP/composite, (2) etch/dry/MIP/saliva/composite, (3) etch/dry/MIP/RMGIC (4) etch/dry/MIP/saliva/RMGIC, (5) dry/SEP/composite, (6) dry/SEP/saliva/composite, (7) dry/SEP/RMGIC, (8) dry/SEP/saliva/RMGIC. The shear bond strength of each sample was tested with a universal testing machine.
Results: The bond strength in the uncontaminated groups had the highest mean shear bond strengths when compared to the contaminated groups although there was no significant difference in bond-failure sites amongst the 8 experimental groups. The composite with SEP have higher bond strength up to 16.66 MPa in an uncontaminated field as compared to all other groups. The self-etching primer with resin modified glass ionomer cement showed higher bond strength up to 12.79 MPa compared to other groups of salivary contamination.
Conclusion: The presence of saliva contamination significantly lowers the shear bond strength of all groups of bonding procedures. Although contamination plays a major setback in bonding procedures, the bond strength of these newer products remains acceptable in most of the conditions