Comparison of Reliance HEMA and Bis-GMA Bonding Resins on Ceramics

Objectives: With the advancement of new ceramic materials for dental crowns, improved methods of bonding orthodontic brackets to these surfaces must be attained. Currently, Emax^® lithium disilicate is being used primarily for anterior crowns and zirconia is being used for the posterior. The purpose of this study is to compare the shear bond strength of Reliance HEMA (Assure^®) and Bis-GMA (Assure PLUS) orthodontic bonding resins on enamel, porcelain, and zirconia materials.
Methods: Two groups were formed, with three tested surfaces per group (n=20). The categories included premolars, zirconia rods and porcelain rods. Group 1 was treated with Assure Universal Bonding Resin and group 2 was treated with Assure PLUS All Surface Bonding Resin. Zirconia rods (1cm x 1cm x 4cm) were used to represent zirconia crowns and IPS Emax CAD rods (Ivoclar Vivadent) (1cm x 1cm x 2cm) were used to represent Emax lithium disilicate crowns. Assure and Assure PLUS bonding agents were applied according to the manufacturer’s specifications, and standard edgewise universal premolar brackets were secured using Reliance Light Bond^TM paste without fluoride. After 24 hours the brackets were sheared with a universal testing machine (Instron^®5566A) and the results were recorded. Data was analyzed using an independent sample t-test. A p-value of less than 0.05 was considered statistically significant.
Results: The P-values indicate that there is no statistically significant difference between Group 1 and Group 2. See tables 1, 2, and 3.
Conclusions: Although Group 1 and Group 2 gave statistically equivalent results, we found that the ease of use when applying Group 2 make it a safer, superior product within the confines of this study. It does not require a four minute hydrofluoric acid etch, and has half the curing time when bonding to ceramic materials.