i don't think there is any, at least for now, as far as being an officer is concerned. the first requirement to become an officer (which comes before dentistry) in the us military is citizenship.
Unless they open the MAVNI program back up (allowing non-US citizens to join and get their citizenship), you need citizenship, a US dental license, and DMD/DDS degree from an accredited US school.
i don't think there is any, at least for now, as far as being an officer is concerned. the first requirement to become an officer (which comes before dentistry) in the us military is citizenship.
That will vary by service and by need. The latest you can come in and still receive a military retirement is 42 yrs old. They can do age waivers above that, but you won't get any type of pension/retirement.