It is possible to use a diagnostic wax-up (DWU) when phasing treatment. It requires modification of the steps taken in the DWU’s fabrication process. The primary reason you modify fabrication steps is if you are going to phase surgical or restorative clinical procedures. The normal step-by-step process used when creating a DWU is followed for the anterior teeth, and then the casts are duplicated for future use in developing guides or stints that fit on preoperative/pretreatment posterior teeth. The process used for the anterior teeth was described in my previous article.
After the wax-up of the maxillary and mandibular anterior teeth has been completed to establish the esthetics and anterior function, the casts are then duplicated. This duplication incorporates the newly designed anterior teeth with the existing posterior teeth. Guides or stents are made from the duplicated casts to allow the clinician to prepare and provisionalize the anterior teeth using the unaltered posterior teeth as a support for the guides.
The next step in the wax-up is to complete the posterior teeth in both arches following the normal protocol. Another duplication of the wax-up would then incorporate all for the changes to the teeth; additional guides or stents can be made from this cast. In some cases during refinement of the wax-up, slight changes may be required of the anterior teeth to idealize the function. Those slight changes would not be incorporated into the initial anterior diagnostic wax-up or the duplication. The final esthetic and functional adjustments should always be completed in the provisionalization phase of patient treatment.
If the treatment plan for the patient involves opening the vertical dimension and the treatment will be phased over an extended period of time, it will require alteration of the posterior teeth in at least one arch in the initial phase of treatment to accommodate the change. Clinicians should prescribe only an additive wax technique on the posterior teeth to accomplish the transition to the new vertical dimension of occlusion. This will allow clinicians to place interim composite bonded restorations on the occlusal aspects of the posterior teeth using stents made from the wax-up or stone cast replica.
Following this technique, the stent fits accurately on the unprepared posterior teeth. An alternative technique is to prepare the posterior teeth and cement provisional restorations using a permanent cement. This can be considered if phasing of treatment involves definitive restoration of those teeth within 12 to18 months.
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Bob Winter, D.D.S., Spear Faculty and Contributing Author