I'm sorry you have Sjogren's and so many dental problems. I have also had a lot of cracked teeth plus many other dental issues. I opted for a partial denture early on (several decades ago), and I am happy with that choice since whenever I lose another tooth, if it can't be crowned, I just have another tooth added to my partial.
Dental implants appear to be a bit less successful in Sjogren's patients, however there is hardly any substantial research on the issue. It is also harder for most Sjogren's patients tolerate the dryness of partials and dentures, so it is a real catch-22 with no ideal solution.
Sometimes gum inflammation and mouth sores makes it very painful to downright impossible for me to wear my partial, or to chew food, but overall I think they are a preferable solution when faced with Sjogren's and microstomia at the same time. I rinse my partial frequently throughout the day and I have even rinsed it in Biotene oral rinse or put a few drops of oral moisturizer on it. I also resort to using denture creams or cushions during some spells, to help soften the blows.
Biotene and similar brands of toothpaste, mouthwash, and mouth moisturizers can be very helpful. If you have cost issues, ask your dentist for all the free samples of dry mouth products they can spare. Sometimes they are deluged with samples and thus very eager to unload a bundle.
When you get your second opinion, be sure to ask whether the cracks could have been caused by overly aggressive dentistry. I have noticed a big difference in style among dentists. I look for a good family dentist who works with children (this is especially necessary when you need child sized mouth appliances due to microstomia) because they tend to have smaller hands and a gentler approach. They say the size of the dentist's hands doesn't matter, because they use tools, but if you've ever had a very large handed dentist working in the back of a very small mouth for a spell, you might beg to differ.