Mechanical properties of two orthodontic adhesive materials polymerized with halogen and plasma curing

The aim of this study is to compare the efficiency of two polymerization techniques (halogen curing--Astralis 7 and plasma curing--Flipo), with two orthodontic adhesive materials (Enlight, a composite resin, and Fuji Ortho LC, a glass ionomer cement).

The efficiency of the polymerization techniques was shown by two mechanical tests. The hardness test was carried out on the exposed and non-exposed surfaces using 10 x 4 x 3-mm samples, polymerized either by halogen curing (40 seconds) or by plasma curing (5 seconds). The three-point bending tests were carried out on 2 x 2 x 25-mm samples polymerized as above. The samples were kept 1 hr at room temperature, then for 24 hrs in distilled water at 37 degrees C.

Whatever the polymerization technique used, the results are similar for hardness and flexion, with the exception of the hardness tests carried out after polymerization with the Flipo light on the surface not directly exposed.

In orthodontic practice, both polymerization techniques can be used. But a multi-bracket session can be long, and the reduction of time spent in the chair obtained by using plasma lamps seems to make this technique preferable.