Thanks for your question.
I never advocate for just feeding dry food. I will sometimes mention that I use a dry food for my cats but that is just because I don’t want to deal with wet food. However, I always say that most practitioners will recommend a combination of both wet and dry food. We have a video ‘Should I Feed My Cat Wet or Dry Food’ that goes cover this specific topic and I encourage you to take a look at it.
When you are dealing with urinary crystals, it is most important to identify what type of crystal is present. There are four different types of crystals and each one is treated differently. Once you determine which crystals present by performing a urinalysis, you can then select a diet to dissolve them. In some cases, you can feed any diet that you like and then add a supplement to change the acidity level of the urine in order to dissolve the crystals. You can ask your veterinarian about the different supplements that exist to dissolve crystals. Depending on the type of crystal, some work better than others.
I would recommend that you feed both a wet and dry diet. The moisture in the wet food helps flush the bladder, while the hardness of the dry food helps to grate the teeth to some degree and may prevent dental disease. You can also consider getting a water fountain for your cat to drink from. Many cats love drinking from these because they like moving water, although there are some cats that are too scared to drink from them. The idea is that encouraging them to drink more water will lead to more flushing of the bladder, but it is critical that you combine this with appropriate pH control of the urine to dissolve or prevent crystals.
I hope this helps. Good luck.
Dr. Clayton Greenway