When I had gotten porcelain veneers done, (I had eight year-old bonding by a previous dentist, before going to this one) I though preparation was only made on the front surface of the tooth, and teeth were cut-back in the backside for crowns only. This new dentist only made almost no preparation to the surface, (except to remove the old bonding) but reduced slightly off the tongue side of my teeth after the placement of veneers! Is this over preparation, or incorrect techique?