The use of extracted teeth for in vitro bonding studies: A review of infection control considerations

Abstract

Objective. Infection control concerns regarding the handling of teeth for research purposes have prompted investigators to evaluate the effects of disinfection/sterilization on extracted teeth. The objectives of this literature review were to assess the reported findings of the effect of disinfection or sterilization on teeth used for in vitro bonding studies and make recommendations on their use. Methods. A search of the literature was performed to obtain background information on infection control guidelines and current findings regarding disinfection or sterilization of extracted teeth. Published articles addressing the effects of different disinfection and sterilizing procedures on the tooth, such as structural changes of dentin and dentin permeability or effect on bond strengths, were examined and compared for agreement or disagreement of findings. The review was organized by the type of disinfection or sterilization method utilized by the investigators. These methods were evaluated in an attempt to address whether disinfection/sterilization of extracted teeth can be recommended or if the procedure simply produces another variable. Results. Formalin, chemical heat sterilization (Chemiclave), autoclave, ethylene oxide and gamma radiation methods of disinfection/sterilization have been investigated for their effects on extracted teeth. When the effect of formalin storage on dentin bond strengths was examined, investigator results were extremely varied. Autoclave and chemical sterilization were found to produce comparable dentin bond results when compared to controls. Gamma radiation did not produce structural changes in the dentin but it currently has not been investigated for its effect on dentin bond strength. And while ethylene oxide produced similar dentin bond strength results when compared to controls, its use as a sterilant was determined to be ineffective. Significance. Investigators have found formalin storage to be effective for infection control purposes. It cannot, however, be recommended as a storage medium for dentin bonding studies due to the variability in dentin bond strengths resulting from its use. Ethylene oxide is also not recommended due to its inability to effectively sterilize teeth. Chemical heat and autoclave sterilization methods are recommended for preventing cross-contamination during in vitro dentin bonding research. This recommendation is based on current research findings which examined the effect of these sterilization methods on dentin and dentin bond strengths.