Should I use work time or personal time to go to the doctor or dentist?

Ideally company time if you can, but generally sick time. However, different companies have different policies on this. One company I worked for allowed scheduled check-ups to be counted against company time while emergency visits would be sick time, so as to encourage preventative health measures. My current company does not track any time off (personal, sick or vacation). Other companies I worked for counted all time off as unpaid vacation time, so be sure to check with your HR department.

Personal time. Obviously.

I think it depends on your job and the general workplace culture. However, I would advise using work time if you can, since most doctor and dentist offices also operate on day time hours and it can be difficult to book evening appointments.

Should use personal time.

Personal for nonserious situations.

Personal time whenever possible

Depends on the job a few jobs offer personal days.

I would probably use my personal time. Although I would most definitely seek out the advice of your HR team if one exists to inquire about how they handle PTO and Sick Time as well.

Personal, unless you were injured on the job.

If you have a doctor or dentist appoint during work hours, that’s consider medical and therefore should be deducted from allocated sick time. I recommend trying to schedule appointments as early in advance as possible, set before office hours or as close to end of day (late afternoon) as possible. If you know months or weeks in advance (as most medical practitioners schedule appoints 6 months, 1 year, or 2-3 weeks ahead) please put these on your calendar; do not wait until the day before to tell your boss “oh, I have to leave early, or I will be in late, because I have a doctor’s appointment”. Emergency appoints are the exception. Illness and emergencies are not planned- when this happens you go and notify management when reasonably possible. You or your family member notify the boss about your absence or late arrival. DO NOT leave the boss guessing. Unexcused absences can lead to termination. This is legal!

Personal otherwise you're riding the clock and will be fired

Personal time

I think you should be given the option to use both. Depending on which fits your schedule better.

It should be considered sick time as it pertains to your health.

Dentist work during normal business hours so it should be ok to visit using work time. If you need to do it repeatedly, it would be prudent to try to mix it up with weekend visits to the doctor.