ABSTRACT
Purpose@#Implant mechanical complications, including screw loosening, can influence dental implant success. It has been shown that torque values are affected by contamination occurred in implant-abutment (I/A) interface. This study aimed to examine the effects of blood, saliva, fluoride and chlorhexidine contamination on reverse torque values (RTVs) of abutment screws in oral conditions. @*Materials and Methods@#50 fixtures were mounted into the stainless-steel holders and divided into five groups (n = 10). Except control group (NC), fixture screw holes in other groups were contaminated with chlorhexidine (CG), saliva (SG), blood (BG), or fluoride (FG). Abutment screws were tightened with a digital torque meter. I/A assemblies were subjected to thermocycling and cyclic loading. The mean RTVs were recorded and data were analyzed with oneway ANOVA and Tukey test. @*Results@#Except for specimens in SG (20.56 ± 1.33), other specimens in BG (21.11 ± 1.54), CG (22.89 ± 1.1) and FG (24.00 ± 1.12) displayed significantly higher RTVs compared to NC (19.00 ± 1.87). The highest RTVs were detected in CG and FG. @*Conclusion@# The obtained data robustly suggest that RTVs were significantly affected by fluid contaminations. Specimens in FG and CG displayed the highest RTVs. Therefore, clinicians should have enough knowledge about probable contaminations in I/A interface in order to manage them during clinical procedure and to inform patients about using oral care products
ABSTRACT
Various pathogenic bacteria and viruses may be transmitted through blood and saliva, both of which may be found on the surface of impression materials. Then the disinfection of impression material, without change in dimensional stability is important. The purpose of this study was to determine the effects of different concentration of sodium hypochlorite [5.25, 2.5, 0.1,. . . 0.05 percent] and different immersion times [1 to 10, 15, 20 minutes] on disinfection of irreversible hydrocolloid impression materials. In this study, we used both gram positive and gram negative bacteria. A household bleach containing 5.25% of sodium hypochloride was used as disinfectant, the irreversible hydrocolloid impression used, was Iralgin. Minimum inhibitory concentration [MICs] were determined using macro dilution method. The contaminated hydrocolloids were then soaked in the different concentrations of NaOCl for the specified disinfection times. 0.6% sodium hypochlorite for 2 minutes was the lowest concentration preventing bacterial growth and disinfecting irreversible hydrocolloid impression in minimum time. Disinfection of irreversible hydrocolloid impressions in 0.6% solution of sodium hypochlorite for 2 minutes was as effective as the ADA protocol of 0.5% sodium hypochlorite for 10 minutes for the considered microorganisms