Modification of Existing Restoration to Screw Retained Provisional

This patient was referred by her dentist for restoration of the dental implant in the central incisor position. She was expecting an experience similar to what other friends and colleagues had described – impression then return for insertion of the definitive restoration (Fig. 1-2).





 

 

 

 

 

 

 

The initial radiograph shows the provisional restoration was made by modification of the porcelain laminate restoration with zirconia core to fit a prefabricated abutment (Fig. 3). The interim restoration was cemented in place with something similar to TempBond. Take a look at the position of the root of the adjacent central incisor – it appears as though the previous restorations of 8 and 9 were contoured to close a midline diastema. Matching the color of a central incisor is a unique challenge, and in this case, matching tissue levels will add to the challenge.



How would you proceed with this case to help the patient understand what procedures would be required to meet her expectations for the final result?

Michalakis [1] published a clinical report on converting an existing metal ceramic restoration into an interim dental implant supported restoration. Specifically, for a single central incisor, using an existing restoration that has been matched to an adjacent restoration has advantages in terms of color and tissue management. It is also helpful in allowing the patient to see any changes that could occur while providing a greater understanding for what may be required in terms of a compromise or in terms of additional procedures to achieve the desired result.

The goal in this case was to improve the contours on emergence of the restoration at the cervical aspect of the modified provisional restoration while eliminating the variable created by the need for cement to evaluate tissue response over time.

The restoration was modified by making an "hour glass" access opening to facilitate the addition of resin to finish out the contours of a screw retained provisional. Due to the zirconia core of the restoration, the feldspathic porcelain surface was shaped and treated with hydrofluoric acid in order to "bond" the composite at the "margins" while having a mechanical lock with adaptation of the resin to the intaglio surface.

The initial emergence contour of the provisional was made with the goal of minimizing the pressure on the gingival tissues. The patient was concerned about the deficient tissue creating the famous black triangle. The provisional was modified six months following initial insertion in an attempt to push the tissue to create more papilla height and maintained for an additional three months (Fig. 4).



How would you proceed at this point?

Modifying the contours of the interim and definitive restoration with perhaps addition of "prosthetic pink" (composite or porcelain) would be the quickest path to the finish line with a compromised result (Fig. 5-7).




Clinical crown lengthening with the significant space between the dental implant and the adjacent central might help or it may make the situation worse – how many teeth should be involved with the crown lengthening? How about a surgical option to facilitate repositioning the implant and adjacent hard and soft tissue?

References:

1) Michalakis K, Kalpidis CDR, Hirayama H. "Conversion of an existing metal ceramic crown to an interim restoration and nonfunctional loading of a singe implant in the maxillary esthetic zone: A clinical report." Journal of Prosthetic Dentistry 111.1 (2014): 6-10

Douglas G. Benting, DDS, MS, FACP, Spear Visiting Faculty and Contributing Author [ www.drbenting.com ]