Final answer:
A military dental officer's examination frequency for a reservist is not specified in the given context, and updated information should be obtained from official military healthcare guidelines or a military medical officer.
Step-by-step explanation:
The frequency at which a military dental officer is required to examine a reservist may not be directly specified in the provided context of the U.S. Marine tank and the changes in drill requirements. However, it's important to note that the healthcare requirements for reservists, including dental examinations, are typically mandated by military healthcare standards and can be subject to change depending on policy updates and specific needs of the service.
Typically, reservists must undergo a dental examination periodically to ensure they are deployment-ready. It is best to consult official military health care guidelines or reach out to a military medical officer for the most current examination requirements.