Why study models are so important to dental technicians?

One of the most commonly asked questions in laboratories is, and has been for many years,”Do we have a preoperative model? Preoperative models, also known as study models, are crucial when constructing anterior restorations.

The dental technician does not have the opportunity to work with a patient. In fact, many dental prescriptions do not provide the necessary information regarding patient age sex or personality. In the multiple unit anterior cases, such as bridges replacing all upper or lower anterior teeth, the information provided by study models will give the technician a better opportunity of a either matching or improving the patients smile and functions.

The length of the anterior teeth, position of the incisal edge, anterior guidance, long axis alignment and direction, as well as shape and labial anatomy, are key indicators the technician needs to notice when constructing anterior cases. These key factors are different for most patients and are important for technicians to know if he or she is going to duplicate or improve on the patient's smile.

They are times when a Dentist is not able to provide the laboratory with study or preoperative models. Accidents, post surgery cases, or those patients who have had dental care from another office and now want to improve their smile, present a difficult obstacle for the dentist and the technician. Pictures of the patient and, as well as detailed information on the prescription, will give the technician a better chance of creating a smile the patient will accept.

Another option for the dentist is to improve the existing dentition by sending preoperative models to the laboratory to enable the technician to provide a diagnostic wax up of the final restorations. The dentist will be able to see what is proposed and work with the patient on any improvements desired.

Preoperative models are also helpful on extensive posterior cases because they provide the technician with an idea of the position of the posterior teeth, as well as information regarding the type of occlusion, group function, balancing contacts, and interior guidance. With this information, the technician will be able to duplicate or improve on all aspects of the case required by the patient and the dentist.

Another critical area is regarding the operative models. A common and frustrating complaint from doctors is high occlusion. While there are many factors that contribute to this problem, one of the solutions is the operative model. Most impressions that laboratories receive for single unit cases are quadrant impressions. There might be a cost of saving in material but the problems with quadrant models is that the technician is not able to create, on the articulator, the function of the patient's mouth. Often there are no anterior teeth to give the technician information about anterior or cuspid guidance and, therefore, the technician will not be able to determine if the normal working side has a balancing contact or not. The technician will have to try to create a three unit bridge involving cuspid to second premolar without knowing what takes place on the opposite side of the patient's mouth.

With good preoperative models and full operative models the technician will have the proper information regarding not only the aesthetics of a particular patient, but the function necessary for a successful case. These benefits far outweigh any cost saving in impression material and will ultimately save the dentists valuable chair time and provide for a happier patient.