No abstract

This paper reports on the mechanical performance of a visible light cured orthodontic bonding agent. It is concluded that this type of material is as effective as other commercial adhesives and offers certain advantages in handling. Resistance to 4kg of force in the shear/peel mode within the first 5 minutes of its application is expected from a clinically usable adhesive.

An in vitro study was carried out resting the shear/peel bonding strength of brackets cemented with a glass-ionomer cement. It was found that the adhesive achieves its optimal bond strength at 24 hours. It is suggested that there is still scope for improvement of the material's mechanical properties and the use of prolonged clinical trials.

A cone-plate viscometer was employed for studying the rheological characteristics of certain unfilled resins and etching gels. Of these, BIS-GMA monomer and its diluted mixtures exhibited Newtonian, dilatant and thixotropic behaviour depending on the shear rate. Other unfilled resins also exhibited various types of behaviour. At high shear rates reproducible hysteresis loops were obtained for etching gels which may be useful in characterization.