Dental Veneers are cosmetic dental prosthetics that are meant to cover the teeth. It is not exactly a prosthetic, in the sense that it replaces something that was lost (as in the case of dentures, dental bridges and dental implants.).
According to Wrong Diagnosis, one of the causes of mucus stools in children is bacterial overgrowth. Normally there is a certain amount of bacteria in the digestive tract. This is healthy and assists in digestion. But if it grows out of control, then it can contribute to mucus in the stool.
Another factor that could contribute to green stool is mucus. Mucus is present in the intestines and can cause stool to change color as it can consistency. Unless there is an excessive amount of mucus or a persistent change from normal bowel movement, it is likely nothing to be concerned with.