What this sentence means is that one aspect of someone's life is not greater than the whole body as a whole and that the summation of one's life make up the whole of a person.
The whole person is believed to be made up of many aspects: physical health and fitness, mental health, emotional health, spirituality, social life, environmental and occupation aspect, etc.
In the health sector for instance, health providers had been advised not to treat people's diseases alone but to take cognizance of the person as a whole; the health aspect is just one of the life aspects of a patient.
Seeing as how a dentist practices dentistry, I believe the answer would be a dentist. Hope this helps!
Stressing could cause many things, which may include you getting very emotional because you are all caught up in your mind you are stressing and keeping it all jumbled up which could make your mental state worse.
