Which of the following is an example of a critical instrument?

A critical instrument is defined as a tool that penetrates soft tissue or bone and carries a high risk of transferring pathogens if contaminated. Needles fit this definition perfectly, as they directly pierce the skin and can become contaminated with blood or bodily fluids that may harbor infectious agents.

The other options do not meet the criteria for critical instruments. Amalgam carriers are used to transport dental materials but do not come into direct contact with blood or penetrate tissue. Probes are diagnostic instruments that may contact the teeth and gums but are not classified as critical instruments because they do not have the same level of risk associated with them; they are typically categorized as semi-critical instruments instead. Autoclaves are sterilization devices, not instruments used during procedures, and thus do not fall into any of the categories of critical, semi-critical, or non-critical instruments.

In summary, needles are categorized as critical instruments due to their direct involvement in procedures that can transmit infections, highlighting the importance of proper sterilization and handling in infection control protocols.