Patients often present wanting to improve their smiles with porcelain veneers. Cosmetic dentistry is often offers excellent options to do so. However, when teeth are broken, chipped, and worn down, this is a warning that something else is not right. Looking at these photos, it is easy to see the damage that has occurred with his natural teeth. These teeth did not come in this way. Most often a bad bite is what causes these issues and this is where more than just cosmetic dentistry needs to be considered.
Why would anyone fix these teeth to the same position that he ruined his teeth in. To do so will ultimately lead to failure of the new dentistry. This is a situation in which "funcitonal cosmetic dentistry" is indicated. Correcting the bad bite, which is the underlying problem, before any restorative dentistry is started is the key to this case. A bad bite can cause several problems, either broken teeth, jaw pain, or muscle pain.
In overview, bad bites can cause severe damage to teeth and should be evaluated prior to beginning any cosmetic dentistry to help ensure long term success. These types of cases are not purely cosmetic but necessary dentistry to help individuals keep their teeth.