Effect of cleaning methods on retentive values of saliva-contaminated implant-supported zirconia copings.

Abstract

The aim of this study was to evaluate the effect of different cleaning regimens on retentive strength of saliva-contaminated implant-supported zirconia copings. Seventy solid titanium abutments with 5.5mm height (Straumann) were attached to the regular neck implant analogs (Straumann). The abutment-analog complex was mounted vertically in an autopolymerized T-shaped acrylic resin block. Seventy zirconia copings with an occlusal loop were made. The copings were contaminated with fresh human saliva for 1min (except the control group). Afterward, the specimens were washed with water spray for 15s and dried for 15s. The copings were divided into seven groups according to cleaning methods (n=10). Group 1: no contamination (control group); Group 2: water spray rinsing; Group 3: airborne particle abrasion; Group 4: immersion in 96% isopropanol; Group 5: applying Ivoclean (Ivoclar Vivadent); Group 6: applying 1% sodium hypochlorite; and Group 7: applying Monobond Plus (Ivoclar Vivadent). The copings were luted with a resin luting agent (RelyX Unicem; 3M ESPE). After 5,000 thermal cycles, the retentive values of the restorations were tested using universal testing machine. The dislodging forces were analyzed using one-way analysis of variance and the Tukey's HSD tests (α=0.05). The copings, which were cleaned with Ivoclean and 96% isopropanol, showed the highest retentive values (204.79±44.49 and 232.65±71.36, respectively). There was a significant difference between the studied groups (F=2.735; p=.02). Tukey's HSD showed that there was no significant difference between the different cleaning procedures and control group except water rinsing group (p=.14). The lowest retentive value was related to the saliva-contaminated group, which were only cleaned with water rinsing method. The retentive values of zirconia-based restorations were adversely affected by saliva contaminations. These restorations can be cleaned by Ivoclean, 96% isopropanol, airborne particle abrasion, 1% sodium hypochlorite, or applying Monobond Plus before luting procedures.