Final answer:
Disinfectants in dentistry must be registered with the EPA and are assessed against a standard, often phenol, to ensure broad-spectrum efficacy. They are categorized by their effectiveness against various microbes and influenced by environmental conditions.
Step-by-step explanation:
Disinfectants used in dentistry must be registered with the Environmental Protection Agency (EPA) as hospital disinfectants with the ability to kill a broad spectrum of microbes. These disinfectants are compared to a standard, such as phenol, to evaluate their effectiveness. Phenol was historically used in aseptic surgery and serves as a benchmark for measuring the efficacy of other chemical disinfectants. Assessments involve comparing the results of a phenol coefficient or alternative methods such as broth dilution or disk diffusion assays. Furthermore, chemical disinfectants are classified based on their effectiveness against various types of microbes. High-level germicides are capable of killing vegetative cells, fungi, viruses, and even endospores, leading to sterilization. Intermediate-level germicides kill most but not all viruses and are less effective against endospores, while low-level germicides kill vegetative cells and some enveloped viruses but are ineffective against endospores. The environmental conditions such as pH, temperature, and concentration also influence the efficacy of disinfectants.