Cat likes tuna again, will this make wet food switch easy?

 
My cat was raised on wet food, for about 15 years she has been on a dry food. She even stopped eating tuna. Recently she started eating tuna again, will this make it easier to switch back to wet food? She had some poop issues a year ago the vet gave me lactulose syrus and royal canin veterinary fiber response. Do I need wet food with fiber? Do cats that eat only wet food need crunchy dental treats? Thank you.
 

There are many tasty incentives to sprinkle on top of the wet food to get your kitty back on track. A lot of us here on site use Whole Life Chicken http://www.amazon.com/s/?ie=UTF8&keywords=whole+life+chicken&tag=&tag=thecatsite or any freeze-dried chicken, beef or liver product. Bonito Flakes is another enticing incentive http://www.amazon.com/s/?ie=UTF8&keywords=cat+man+doo+bonito+flakes&tag=&tag=thecatsite ( I order off of Amazon - but you can find these at some specialty natural stores and other appetite incentives for changing foods. You just have to see what you cat likes. Tuna could also be used but your cat might just lick off the tuna and then be done with the rest of the meal. If you can get something to sprinkle on the wet food that would be better. You can add fiber to your cat's diet as well if the vet thinks it is still needed. Canned plain pumpkin is good and some cats readily eat that.

Thanks for the advice.