If you use past simple, it refers to some time in the past. If you use present perfect, it refers to the past extending up to now.
That's not exactly true, Pieanne. If it was as simple as that there would be no reason for the present perfect. The PP adds importance to a past action. It's often described as making something current.
1. Paul has had to have all his teeth removed because of gum disease. 2. Mr. Jones has had to have dinner with his mother-in-law every day this week, poor guy. 3. Marcie has had to have the exterminator to her house twice now because of termites. 4. The boss has had to have had doubts about the honesty of that employee. O
1. example 2 - Does it imply Mr.jones have to dine with his mother-in-law every day this week?. If so, How PP can be used in this case? 2. example 4 - I do not understand the structure "has had to have had"