[Glass ionomer cements as orthodontic bracket adhesives. An in vitro study with 4 glass ionomer cements (GIC) and 2 conventional orthodontic bracket adhesives as the comparative group].
240 orthodontic brackets were bonded to buccal surfaces of bovine teeth. As bonding material we used four glass ionomer cements without etching and two normal orthodontic bracket bonding materials with etching of enamel. Brackets of group 1 were tested with a material testing machine for shear and tensile strength after ten minutes. Brackets of group 2, 3 and 4 were tested after one day, 28 days and 98 days, respectively. In the average the bonding strength of glass ionomer cements was 50% less than the bonding strength of the comparison group with etching. The fracture of the bonding took place to 80% between the mesh base and the glass ionomer cements. Defects of the enamel surface were never observed. The bonding between mesh-base and glass ionomer cements has to be improved before the use of this bonding material can be recommended for the use in a busy practice.