Abstract
Purpose: This study examined the influence of cleaning agents on the bonding performance of a resin luting cement to saliva-contaminated core foundation resin by means of shear bond strength (SBS) and surface free energy (SFE) measurements.
Methods: The agents used for removing saliva contamination were: Katana Cleaner (KC, Kuraray Noritake Dental), Multi Etchant (ME, Yamakin), and Ultra-Etch (UE, Ultradent Products). Panavia V5 (Kuraray Noritake Dental) was used as a resin luting cement. Core foundation resin surfaces were ground with SiC papers, ending at #320 grit. To create saliva-contaminated resin surfaces, 10 μl of human saliva was applied to the ground surface. Uncontaminated resin surfaces were prepared as a control group. The saliva-contaminated specimens were divided into four groups, treated with one of the cleaning agents (KC, ME, or UE) or without any treatment (SC group). A stainless-steel metal ring was placed over the bonding area, and the luting agent was condensed into the ring and light irradiated. The assembled specimens were stored in 37°C water for 24 h. Half of the specimens in each group were subjected to thermal cycling (TC) for 10,000 times. SBS tests were conducted on each group at the crosshead speed of 1.0 mm/min. For SFE determination, specimens were prepared as for the SBS tests. The contact angles of three test liquids that have known SFE parameters were measured using a contact angle meter. Scanning electronic microscopic observation was also performed.
Results: After 24 h storage, although the SC group showed a significantly lower SBS value than the control group, the cleaning agent treated groups showed higher SBS values than the SC group. After TC, the cleaning agent treated groups showed significantly lower SBS values than the control group, but significantly higher SBS values than the SC group. Although SC showed significantly lower SFE values than KC and ME, the SFE value after cleaning agent treatment depended on the material.
Conclusion: After saliva contamination of core foundation resin surfaces, treatment with the cleaning agents might be helpful for enhancing the bonding performance of resin luting agents. The SFE values of cleaning agent treated surfaces were different due to their cleaning mechanisms.
