Gum disease is a separate issue from veneers but with all dental restorations, it is advisable to make sure the foundations are healthy before improving the appearance.
A crown is like a house, and our gums are like the foundation. If the gums are not healthy, the foundation is not stable and it will not be ideal to build the “house” (crown) on it. Hence, it is crucial to ensure that all active gum disease is removed before having any cosmetic work done.
With the presence of gum disease, it increases the failure rate of not only veneers, but also crowns, bridges and dental implants.