Reproducibility of sterilized rubber impressions

Abstract

Impressions, dentures and other dental appliances may be contaminated with oral micro-flora or other organisms of varying pathogenicity from patient's saliva and blood. Several approaches have been tried to control the transmission of infectious organisms via dental impressions and because disinfection is less effective and has several drawbacks for impression characterization, several sterilization methods have been suggested. This study evaluated the reproducibility of rubber impressions after sterilization by different methods. Dimensional accuracy and wettability of two rubber impression materials (vinyl polysiloxane and polyether) were evaluated after sterilization by each of three well-known methods (immersion in 2% glutaraldehyde for 10 h, autoclaving and microwave radiation). Non-sterilized impressions served as control. The effect of the tray material on impression accuracy and the effect of topical surfactant on the wettability were also evaluated. One-way ANOVA with Dunnett's method was used for statistical analysis. All sterilizing methods reduced the reproducibility of rubber impressions, although not always significantly. Microwave sterilization had a small effect on both accuracy and wettability. The greater effects of the other methods could usually be overcome by using ceramic trays and by spraying impression surfaces with surfactant before pouring the gypsum mix. There was one exception: glutaraldehyde still degraded dimensional accuracy even with ceramic trays and surfactant. We conclude that a) sterilization of rubber impressions made on acrylic trays was usually associated with a degree of dimensional change; b) microwave energy seems to be a suitable technique for sterilizing rubber impressions; c) topical surfactant application helped restore wettability of sterilized impressions.

Effect of disinfection and sterilization on the tensile strength, surface roughness, and wettability of elastomers

“…Once the impression is removed from the oral cavity, it is sterilized in order to remove food debris and disease causing microorganisms. Failure to do so will lead to the spread of infection among dental professionals . The transmission of pathogenic microorganisms has caused concern among dental office staff and laboratory personnel, and has led to initiative for researchers to recommend possible techniques to disinfect the impression .…”

“…Dental professionals, including dental hygienists and dental technologist, are widely exposed, either directly or indirectly, to a wide variety of microorganisms during their daily practice . In order to combat this, the disinfection and sterilization of dental instruments and materials, including impressions, are recommended by the American Dental Association (ADA) and the Centre for Disease Control to prevent possible transmission of infectious diseases, such as hepatitis B, HIV, and tuberculosis .…”

“…Thus, the ADA has put forward strong regulations for disinfection protocols for all dental instruments and materials. According to the ADA guidelines, all dental impressions should be thoroughly rinsed to remove blood, saliva, and food debris, followed by disinfection using glutaraldehyde, sodium hypochlorite, iodophor, or phenol …”

“…However, the retention of microorganisms on impression surfaces, even after thorough rinsing, is expected, and sometimes does not clear blood and saliva, especially from deep undercut areas. Alternatively, impressions could be cleansed with a very soft brush . Failure to do this results in cross‐contamination and the spread of infection .…”

Farkli Dezenfektan Ajanlarin Si̇li̇kon Esasli Ölçü Maddeleri̇ni̇n Yüzey Pürüzlülüğüne Etki̇si̇

“…9 Amerikan DiĢ Hekimleri Birliği (ADA) dezenfeksiyon için ölçü maddelerinin yıkanıp kan ve tükürüğün tamamen uzaklaĢtırılmasını takiben hipoklorit, iodofor, gluteraldehit veya fenol bileĢiklerinde 10-15 dakika süreyle bekletilmesini önermiĢtir. 10,11 Ancak ölçülerde kullanılmakta olan dezenfeksiyon yöntemlerinin ölçü-nün stabilitesi ve yüzey netliği gibi özelliklerini olumsuz yönde etkilediği belirtilmektedir. 12,13 Bu çalıĢmamızda farklı dezenfektan ajanların silikon esaslı ölçü maddelerinin yüzey pürüzlülüğü üze-rine etkisinin incelenmesi amaçlanmıĢtır.…”