The dentist may feel that temporary dental veneers should be worn by the patient during that time frame while the porcelain veneers are being fabricated, but this is not always the case. The need to place temporary dental veneers is usually based on either the amount of tooth reduction that has been required or else the appearance of the prepared teeth, or both.
If the amount of tooth reduction that has taken place has been minimal (as is often the case) it is possible that no temporary dental veneers are needed. The surface of the prepared teeth will no doubt feel somewhat rough but in most cases this should not pose much of an inconvenience. On close inspection the prepared teeth may look somewhat different or altered but for most casual contact with other people (where typically the other person will be at least a foot or two away) the appearance of the prepared teeth may not be all that much different from the way they appeared before the veneering process was begun.
Since a thin portion of the enamel layer of the tooth has been removed this layer will have lost some of its insulating capability. This means that the dental patient can expect that a tooth prepared for a porcelain veneer may have an increased sensitivity to hot and cold stimuli such as foods or beverages.
One advantage of not having temporary dental veneers placed is one of cost. Making temporary veneers takes time and effort on the part of the dentist. In those cases where temporaries are need one can expect that the cost of their porcelain veneer case will be somewhat higher.
In those cases where a relatively greater amount of tooth reduction has taken place the dentist may feel that the placement of temporary dental veneers is needed. They may feel that the potential for tooth sensitivity is great enough that the prepared surface should be covered over. In other situations the shape of the prepared tooth can be objectionable enough that a temporary dental veneer is warranted. This is especially likely in those instances where a part of the veneer preparation included a reduction (shortening) of the biting edge of the tooth.
It's beyond the needed scope of this general discussion to elaborate on the precise manner in which a dentist will make temporary dental veneers, if for no other reason than that there are a few different methods a dentist may choose to use. Once the temporary veneers have been placed you cannot expect that they are attached to your teeth as firmly as the porcelain veneers will be. Clearly one goal the dentist will have in mind when they place temporary dental veneers is to anchor them in a manner where they will not be so difficult to remove that there is potential for damaging or altering the tooth's prepared surface. During that time frame when you are wearing temporary dental veneers you will need to exercise some caution and limit your oral activities somewhat so you do not inadvertently dislodge them.
As a point of interest you might ask your dentist if the temporary dental veneers they have placed are intended to mimic the shape and contours of the porcelain veneers being fabricated. Some temporization methods allow for this and if this is the case then this is a chance for you to discuss with your dentist those aspects of the changes that you do or do not like. Your dentist can then communicate your preferences to the dental laboratory technician who will fabricate your porcelain veneers.