Have in this case, when used with the infinitival to, (with or without a main verb) means to be required, compelled, or under obligation to do something. The present perfect tense is a combination of have and a participle.
I have gone to the dentist.
I have seen his drills and needles.
The present perfect progressive tense is:
I have been going to the same dentist for five years.
I have been sitting in his waiting room for the past six years.
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