The advantages of using a veneer to restore a tooth are many. Very good aesthetics can be obtained, with minimal tooth preparation (i.e. drilling). Normally a reduction of around 0.5 mm is required for porcelain veneers on a labial tooth surface. Composite veneers are becoming more popular as they are easy to repair, whereas porcelain veneers have a tendency to fracture. It can be very difficult to match the shade of an individual veneer to the remaining teeth, hence the tendency to place several veneers.
Veneers may be used cosmetically to resurface teeth such as to make them appear straighter and possess a more aesthetically pleasing alignment. This may be a quick way to improve the appearance of malposed teeth without need to use orthodontics. However, the amount of malposition of teeth may be such that veneers alone may not be enough to correct the esthetic imbalance. Instead, orthodontics would need to be used, or orthodontics combined with veneers. The dentist who places veneers must be careful, because veneers could increase the thickness of the front face of the teeth. If the teeth are too thick on the face they may appear to stand out and push out the lips. The effect may be enough to give the patient a full or chipmunk appearance when the lips are closed. Veneers must also be created such that the patient bites into them with minimal force. Otherwise, they may chip off. So, patients whose lower jaw protrudes out farther than their upper jaw, otherwise known as a class III bite, may not be good candidates for veneers because the teeth of the lower jaw may bite into the teeth of the upper jaw such as to dislodge the veneers.