The separation of dental and medical care is a medical ethics issue because it negatively impacts vulnerable populations who lack access to dental care.
AMA J Ethics. 2016;18(9):861-868. doi:
10.1001/journalofethics.2016.18.9.peer1-1609.
Dr. Jones has a duty to determine how the test results were lost and why, disclose this information to his patient, Mrs. Taylor, and see that she is not held responsible for the costs of rerunning the test.