Nano Composites and Light Cure Composites - A Comparative Assessment of Bond Failure Rates

Nano Composites and Light Cure Composites - A Comparative Assessment of Bond Failure Rates

This randomized clinical trial is aimed to evaluate the bond failure rates of the brackets bonded with nano-hybrid composites (Filtek Z250) to that of conventional composites (Transbond XT)

Orthodontic brackets are attached to the teeth with a robust bonding material called composite resin, however sometimes the bond between the braket and the tooth surface may fail halting the desired tooth movement. Repeated bond failures like these are inconvenience both for the orthodontists as well as the patients. With each bracket loosening due to bond failure, treatment time is prolonged as the activation planned on eash visit is delayed resuling in increased treatment time.

Nanotechnology has recently made a breakthrough in dental materials through incorporation of nanoparticles. Composites containing nano-filler particles exhibit higher compression strength, flexural strength, elastic modulus and wear resistance (Rabia and Bilal). In vitro studies have shown that nanohbrid composites have shear bond stregnths similar to that of conventional composites however the environment of oral cavity is challenging and there are no long term clinical trials to validate these results.

The aim of this study is to compare the rate of bond failure between the brackets bonded with nano hybrid composites and that of the conventional composites over a period of six months.

Inclusion Criteria:

• Patients having treatment with fixed metallic orthodontic appliances
• Patients in whom both upper and lower arches are bonded in single visit

Exclusion Criteria:

• Patients with variations in morphology of teeth
• Patients with defective enamel, dentine and cementum
• Patiens with parafunctioal habits
• Patients with restorations involving the facial surface of teeth