The material of your porcelain veneers will not decay, but the underlying tooth is still susceptible to tooth decay and may develop a cavity without proper dental hygiene. You need to floss once a day and brush twice a day to maintain good oral health. Bacteria buildup is a concern for cavity formation and gum disease development. Gum disease can wreak havoc on your mouth but also affects the appearance of your porcelain veneers if your gums start to recede and reveal the edges along your gum line.