Officials at the Veterans Affairs Pacific Islands Health Care system say 20 patients were potentially exposed to blood-borne pathogens in May after dental instruments were used that were "clean" but had not completed the sterilization process. VA officials say the risk is extremely low, but staff have contacted those patients who may be affected.  The instruments had been sent to Tripler Army Medical Center for sterilization, and when they were returned, wrapping indicated the instruments had been cleaned, but not completely sterilized. The VA apologized for the error and has taken various steps to ensure the same mistake is not repeated.