This article is a continuation of the series discussing when a diagnostic wax-up (DWU) should be completed. It will cover when to prescribe a wax-up in cases that require restorative and periodontal or implant procedures.
DWUs may be fabricated pre-periodontal treatment when two different scenarios exist. The first is when there are no existing restorations in place, and the second is when restorative treatment was previously completed.
- If the periodontal treatment involves crown lengthening or root coverage procedures, first establishing the ideal incisal edge position is recommended. Once the incisal edge position is determined, the gingival level is established based on tooth proportion desired (length to width). If interim or definitive composite restorations are planned to restore the incisal edges, prescribe an additive wax-up pre-treatment. The matrix made from the wax-up is then used clinically to establish the incisal length. After the teeth are restored, an impression is made to fabricate a cast. An overlay surgical guide can then be made on this cast if desired.
- A diagnostic wax-up is recommended in cases where existing crown restorations will be replaced and periodontal surgery is planned to change gingival levels to resolve a biological width problem through crown lengthening. It is also recommended when crown lengthening is being performed for esthetic reasons. Removing the crown(s) is necessary to determine the structural integrity of the teeth. In either scenario, provisional restorations can be fabricated from a DWU and used to guide the healing of the surgical site. Ideal morphology of the transitional restorations is required. There are two different types of wax-up depending on the surgical approach.
- The DWU is designed to reflect the current tissue level. This type of DWU is used when the old restorations will be removed and provisionals fabricated to the current gingival level. When periodontal surgery is performed, the gingival tissue level is altered based on the incisal edge position. After the tissue heals for four to six months, the teeth are re-prepared and the provisionals relined.
- The DWU is fabricated after the gingival level is altered on the cast to reflect the desired tissue level after periodontal surgery. Because the technician does not know the size, position, depth, or angulation of the roots of the teeth, the tooth form in the gingival third is only an approximation.
If the restorative phase of treatment involves indirect restorations, new impressions are taken four to six months post-surgery. This ensures that the gingival level and papillae are mature and in a stable position. The DWU follows the same protocols as restorative-only treatment.
A DWU may be prescribed before implant placement in both simple and complex cases, as the implant placement is prosthetically determined or outcome-based. The type prescribed is determined by whether the adjacent teeth will be restored.
Teeth adjacent to the implant will not be restored:
- For cases that require implant placement next to natural teeth, the wax-up essentially creates an anatomically correct pontic. A surgical guide can then be made, which is supported by the adjacent natural teeth.
Teeth adjacent to the implant will be restored:
- For cases that require implant placement next to teeth that will be restored, the DWU should be prescribed for all the teeth that will be included in treatment. Preparation and provisionalization of the natural teeth is commonly the best treatment choice if there is significant alteration in tooth position and morphology. A pontic will extend over the implant site. The surgical guide is made to fit on the prepared natural teeth.
Depending on the complexity of the case and number of implants a new DWU may be necessary because of the position of the implant or the tissue level. The DWU should be made on a cast from a tissue-level impression of the implants.