My husband has been diagnosed nearly 17 years. He’s 72. It’s only in the past year he’s really started to struggle a lot with Parkinson’s symptoms which manifest mainly as lack of strength, very slow movement, and excessive day time sleepiness. He does have a tremor at times but it’s not the worst symptom by any means. As a result of the PD or possibly the drugs he takes, his oral health suffered to point where he lost all his upper teeth and was fitted with a NHS full upper denture. He has struggled ever since it was fitted to keep it in place even with the strongest adhesive. He does have a lot of saliva and we wondered if that might make matters worse. Can the doctors give him anything to stop the excess saliva? His dentist referred him last year to a private Prosthodontist who specialises in dentures etc. He told us that the denture was a good one and fitted well. But that there were always going to be limitations to the NHS dentures. (He would say that, or is that me being cynical). Anyway he said he could make and fit a private denture which would be more carefully designed to my husband’s exact measurements. But the cost was £3500 and even the prosthodontist said he couldn’t guarantee 100% it would stay in place either. So I’ve been looking into dental implants as I found that one or more implants can be used to secure a denture in place permanently. And from the very few research papers written, it seems this does often work well for a lot of Parkinson’s patients (those who can afford the cost!). Does anyone else have (a)experience with dentures falling out a lot or (b) dental implants fitted since being diagnosed and how have you found it? The cost of implants is even higher than a private denture so it’s not a decision we would take lightly as we’d have to dig deep into our savings. But my husband’s self esteem has dropped through the floor because of this. He feels embarrassed to be in company socially in case his denture falls out. But without them he struggles to eat or talk properly. Yet another challenge PD has presented him with. 
I opted to have all my teeth removed and have implant supported dentures over extensive treatment (several root canals and crowns) due to a dental phobia I developed because local anaesthesia doesn’t work properly on me. The extractions and implants were therefore performed under general anaesthesia and I was under for seven hours! At that time I hadn’t been diagnosed. I put various non motor symptoms down to menopause (I was 53 at the time) and just thought my left hand/arm had got weak and that my left leg was stiff. I felt dreadful after the procedure and was dizzy and unwell for a couple of weeks. I believe this was due to the anaesthesia combined with PD. My dentist was concerned about how poorly I felt and asked me if I was sure I didn’t have an illness! Everything made sense once I was diagnosed a year later.
I now know that some types of anaesthetic are not so suitable for patients with PD and wonder whether the drugs used fell into this category so I would say discuss treatment options carefully. Local anaesthesia is best but sitting for a couple of hours in a dentist’s chair can be challenging for people with PD.
Despite all that I went through, it was the right choice for me. My secured denture feels entirely natural and I can eat whatever I like and am no longer self conscious about my teeth. My constant dental anxiety has gone and it’s one less thing to worry about.
Implants stay put, but they need good bone and can take months to heal. Dentures are quicker but might move around. Ask your dentist what suits your situation and comfort best.
I have seen an advertisement for silicon dentenures that are easy to fit , no trauma required.
I went through something similar and decided on implants. The thing that helped was researching affordable options abroad. I found https://www.colinadental.com/services/dental-crowns-in-costa-rica-procedures-and-prices/ and realized the savings could be significant. The process seemed straightforward, and the reviews were positive. Traveling for dental work wasn’t something I had considered before, but seeing the difference in cost made me give it a second thought.