Effect of Chitosan, Cymbopogon citratus, and Ultraviolet-C Disinfection on the Surface Accuracy and Dimensional Stability of Polyvinyl Ether Silicone (PVES) Impression Material: An In Vitro Comparative Study.

Background Dental impressions often become contaminated during clinical use and must be disinfected before laboratory handling to prevent cross-infection. Disinfection methods, however, can influence key properties such as surface detail reproduction (SDR) and linear dimensional stability (LDS). Polyvinyl ether silicone (PVES), a hybrid elastomer, offers strong dimensional accuracy and hydrophilic behavior. Aim This study investigated the effects of 0.5% chitosan, 30% Cymbopogon citratus (lemongrass), and ultraviolet-C (UV-C) radiation on the SDR and LDS of PVES impressions. Materials and methods Seventy-two PVES specimens were prepared under American National Standards Institute (ANSI)/American Dental Association (ADA) No. 19 and International Organization for Standardization (ISO) 4823 standards, then randomly divided into four groups: control (Group I), 0.5% chitosan (Group II), 30% C. citratus (Group III), and UVC radiation (Group IV), each with 18. Groups II and III were immersed in disinfectant solutions for 10 minutes, while Group IV was exposed to UV-C light (254 nm) for the same period. SDR was examined under a stereomicroscope (×10), and LDS was measured with a digital vernier caliper. Readings were taken at 15 minutes (T1) and 12 hours (T2). Statistical analysis employed chi-square, one-way ANOVA, and repeated-measures ANOVA, with p<0.05 considered significant. Results No statistically significant differences were observed among the groups for SDR at T1 (p=0.428) or T2 (p=0.320). The UV-C group demonstrated the highest frequency of ideal SDR scores at both evaluation periods. Similarly, LDS values were comparable among all groups, with no significant differences at T1 (p=0.558) or T2 (p=0.976). All disinfected groups exhibited dimensional measurements within clinically acceptable limits. Conclusions Disinfection of PVES impression material using 0.5% chitosan, 30% C. citratus, and UV-C radiation did not adversely affect surface detail reproduction or dimensional stability. Among the tested methods, UV-C radiation demonstrated the most favorable surface detail reproduction, while C. citratus showed dimensional stability comparable to the control group. All three disinfection protocols may be considered suitable for routine clinical use.