Knoop microhardness test in polymers used for surgical guide manufacturing after the disinfection process

Abstract

Objective: To analyze the Knoop microhardness of samples made from Dima® Print Guide polymer (Kulzer – Brazil) after different disinfection methods. Material and Methods: A total of 15 samples of the Dima® Print Guide polymer (Kulzer – Brazil) were fabricated and divided into five groups with three samples in each group as follows: 1 - control group (C), in which the samples did not undergo any disinfection method; 2 - disinfected with 2% chlorhexidine (CHX); 3 - disinfected with peracetic acid (PA); 4 - disinfected with 70% alcohol (AL); and 5 - sterilized in an autoclave (AS). Three microindentations were made on the surface of each specimen using a 300 g load for a dwell time of 30 seconds, measured with a microhardness tester model HMV-G21DT (Shimadzu Corporation, Kyoto, Japan). Results: The microhardness results were submitted to one-way ANOVA, which showed statistically significant differences (p<0.001), followed by Tukey’s test. The mean and standard deviation of the samples by group were: C (33.26±1.49a); CHX (29.71±1.69a); AP (32.23±0.33a); AL (30.81±2.10a); and AS (25.46±1.18b) (p<0.05)). Conclusion: The samples sterilized in an autoclave showed a decrease in microhardness, while the other disinfection methods did not significantly alter the microhardness of the surgical guides.

KEYWORDS

Computer-assisted surgery; Disinfection; Hardness test; Sterilization; Three-dimensional printing.