The addition of carbon nanotubes to orthodontic adhesives: An in vitro study

Abstract

Objective: The evolution of adhesive dentistry and the addition of nanoparticles has heralded an improvement in the mechanical properties of adhesives. Thus, the aim of the present study was to evaluate the effects produced by carbon nanotubes (CN) added to two adhesives used for indirect bonding by an examination of the shear bond strength (SBS) and location of bond failure. Methods: One hundred and sixty bovine incisors were randomly divided into eight groups (N = 20): (1) indirect bonding with Sondhi adhesive; (2), (3) and (4) indirect bonding with Sondhi adhesive into which CN at 0.5%, 0.25% and 0.05% concentrations were incorporated; (5) indirect bonding with Concise adhesive; (6), (7) and (8) indirect bonding with Concise adhesive into which CN at 0.5%, 0.25% and 0.05% concentrations were incorporated. Following etching with 37% phosphoric acid and the placement of brackets, maximum shear bond strength (SBS) was measured with a mechanical testing machine. The location of bond failure was evaluated using the Adhesive Remnant Index (ARI). The SBS between groups and ARI scores were statistically analysed (p < 0.05). Results: There was no statistical difference (p > 0.05) in SBS or ARI. Conclusions: CN addition to Concise and Sondhi adhesives did not influence the SBS and the ARI of the brackets. Therefore, in the conditions of this experiment, there was no benefit in the addition of CN to orthodontic adhesives.