Its true that is very hard to answer. Some have raised a wall between them and the others, which is hard and some times impossible to accept, think or discuss with others a solution to your problem. Some their lives have followed a track of a circle that never ends and everyday they start moving on the circle trail from the same point. Its like an exusting routine which you have accepted to do to avoid problems where they appear and grow every day.
If you are asking on how to prevent someone from suicide, I am sorry but I must tell you that you will try but in the end its up to him not to do it.
To be actual to your question for the dentist, I assume that popularity wasnt his loving way of being. There are so many people that determine their lifes from a younger age for their future and they walk that way. But in the ned when you do that all you come to yourself thinking that it took you so many years to be there and you find out that there was not that important to be there and you sacrifized all those years.
You can correct what is wrong but you cannot change the past you has. You cannot correct the past. Past is something that has been done and if that history of your is the reason you are thinking of suicide, its up to you to accept it and live with the mistakes of the past.