[Glass ionomer cements used as bonding materials in orthodontics]

The objective of the present study is to test the suitability of glassionomer cements quantitatively for bracket bonding. Premolar brackets were fixed under oral conditions with the following luting glassionomer cements on freshly extracted premolars of adolescent patients: FUJII (GC Dental Industrial Corporation, Tokyo); KETAC CEM (Espe, D-8031 Seefeld); AQUACEM (De Trey, Zürich). Enamel conditioning was carried out with polyacrylic acid, tannic acid and tubulizid (Dental, Therapeutica, S-Nacka). A conventional acid etching technique using concise (3M, D-4040 Neuss) was carried out as a control. The tensile bonds strengths were measured using a Wolpert universal test machine (no. T ZZ 707). In unconditioned enamel, the bond strengths of AQUACEM and KETAC CEM are significantly (p = 0.001) in excess of that of FUJII. By enamel conditioning, the bonding can be raised to a mean value of 6.8 MPa (AQUACEM), attaining about 60% of the values in conventional acid etching technique. The enamel consistency after debonding is discussed with reference to scanning electron micrograms. The results indicate that glassionomer cements should be tested as bracket bonding material in clinical studies.