Welcome to the Forum.  Thanks for your question.  I'll be glad to comment.

Dentists are expected to, and do, use the same precautions to prevent spread of infection from patient to patient as other health care professionals. Medications come in single dose, single use containers and needles are never reused.  Needles and other sharp objects are immediately placed in dedicated containers for disposal following use.

As a result, going to the dentist is an absolutely safe in terms of risk for HIV or similar infection.  Over 25 years, there was a case of a single dentist who intentionally appeared to have infected a patient through dental procedures.  He was discovered and, I believe, prosecuted for this.  Since then, I am unaware of a single HIV infection acquired as a result of spread through dental procedures.  I would not worry.

I hope that this information is helpful.  If there are additional specific questions, please feel free to use your up to two follow-up questions for clarification.  EWH