Porcelain vs. Composite Veneers
Porcelain veneers have a beautiful shine to them and should match the texture of your natural teeth. Some natural teeth are not shiney and you can make the porcelain match that finish as well.
Composite veneers can look great-they usually match your tooth so well that you really should not see a transition. They are usually less shiney.
You can go for a second opinion to check but try wiping them off with a tissue and look at how they appear. Both have advantages and disadvantages.
Porcelain veneers and bonding usually look different
Usually a trained dentist can tell the difference between porcelain veneers vs. bonding both clinically (when we do your exam) as well as radiographically. Porcelain and bonding look different on xrays. Also, if it took you 2 visits to have your teeth done, one in which they were prepared and the next in which the veneers were bonded on, you most likely have porcelain veneers (although, some labs can make lab-fabricated composite veneers which are stronger than chairside bondings). If it is done in one visit and you didn't have impressions done and leave with temporaries, you most likely had composite bonding done.
Porcelain Veneers or Bonding
It is fairly easy for any dentist to be able to ascertain if your restorations are procelain or composite. If in doubt, see a reputable dentist in your area for a second opinion. Another factor is that most veneers require two appointments. The first involves preparation of your tooth structure followed by a impression that is sent to the lab. The second appointment is generally two weeks later when the veneer is bonded to the tooth.
It is usually fairly obvious to any dentist as to whether the veneers are porcelain or composite. Just make an appointment for a "second opinion" consultation.
Porcelain veneers look better than composite
It usually is pretty obvious if they are porcelain or not. If it took two visits, then you know it is not bonding, or direct composite veneers. Composite veneers CAN be indirect but normally are "monochromatic" (one color). Well made porcelain veneers are usually a few colors, to look more natural.
A dentist can tell very easily, but perhaps the "average person" would be challenged.