Composite Adhesion Performance in Focus: a Shear Bond Strength Analysis

The goal of this study was to test and compare how well three modern composite materials - Charisma Classic (Kulzer), G-ænial Anterior (GC Corporation) and Omnichroma (Tokuyama) - adhere to enamel surfaces that were prepared in the same way for all three of them.

Fifteen human teeth were extracted out, cleaned and kept in isotonic saline for the study. Before the adhesive system was applied, the enamel surfaces were etched with 37% phosphoric acid, cleaned and dried. Each composite was poured into standardised cylindrical moulds (3 mm diameter, 3 mm height) and light-cured for 40 seconds. The specimens were placed in epoxy resin and evaluated using an Instron 8872 universal testing equipment to determine shear bond strength. Five tests were conducted on each material and the mean results were identified by leaving out the outliers.

G-ænial Anterior had the highest average SBS value (about 341 N), followed by Omnichroma (about 269 N) and Charisma Classic (about 266 N). Notably, two G-ænial samples showed cohesive fractures within the composite, which means that the bonds between the different parts are very strong. Most of the time, the Charisma and Omnichroma samples failed to adhere at the tooth-composite interface.

G-ænial Anterior had the best adhesion to enamel among all examined materials. This was shown by both the bond strength and the way the bond failed. The results indicate that using it in high-stress clinical situations may make it work more effectively and last longer. Even though Charisma Classic and Omnichroma demonstrated steady and moderate adherence, improved adhesive procedures might help them achieve the best possible clinical results.