Customized Impression Post: An Innovative Approach for Esthetic Implant Restorations

An esthetic and functional implant supported restoration in the esthetic zone is a clinical challenge. The correct three dimensional positioning of the implant in the apico-coronal, mesio-distal and bucco-lingual dimensions and proper management of the peri-implant soft tissue is required to achieve the desired emergence profile. Various surgical and restorative techniques have been employed for achieving ideal soft tissue contours ^{1, 2}. Use of customised abutments to develop and maintain the interdental papilla is one such example of a non-surgical technique ³.  The soft tissue profile around a central incisor is rounded triangular in shape. The geometry of the stock impression posts is generally round cylindrical in shape. Due to this discrepancy in shape, they do not allow proper reproduction of the desired soft tissue emergence profile onto the master cast. Customized impression posts prevent soft tissue collapse or distension of the gingival cuff during the impression procedure and a better record of the soft tissue is obtained. This results in a proper reproduction of the implant and soft tissue situation onto the master cast ⁴.

An impression post can be easily customised to support the soft tissue profile present around the implant ^{5, 6}. A simple and cost effective technique has been described below by which the soft tissue contours around the implants can be recorded and transferred to the master cast.

Procedure:

At the second stage surgery, the healing abutment is customized to the preferred emergence profile using light cured composite resin (Filtek Z350, 3M, St. Paul, MN, U.S.) (Photo 1). At the appointment for recording the impression, the customized healing abutment is removed from the mouth and is attached to the laboratory analog. This assembly is then embedded in

                                                           

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silicone putty. (Speedex, Coltene Whaledent, Coltène Whaledent AG, Altstätten, Switzerland) The buccal surface of the abutment is marked out on the putty block to assist in orientation of the impression post in the future (Photo 2(a,b).

Keeping the laboratory analog in place within the putty, the customized healing abutments is then unscrewed and a stock impression post is attached in its place. Customization of the impression post is done by flowing Protemp 4 (3M, St. Paul, MN, U.S) within the space between the impression post and the silicone putty (Photo 3).  On setting, the resin portion of the customised impression post is smoothened and polished (Photo 4). The other materials that can be used to customise the impression posts can be pattern resin and flowable composites.

The customised impression post is then fitted onto the implant and the soft tissue contours are checked (Photo 5). An open tray impression is made using vinyl poly siloxane. A laboratory analog is attached to the customized impression post and a gingival silicone (Gingitech, Ivoclar Vivadent Inc, Amherst, New York) is flowed around the impression post. The master cast is made thereafter. In this case an abutment was customized using zirconia (Photo 6) (Lava, 3M, St. Paul, MN, U.S.) in the per mucosal region to support the recorded soft tissue contour and an Emax crown (Ivoclar Vivadent, Ivoclar Vivadent Inc, Amherst, New York) was used as the final restoration (Photo 7).

Summary:

The technique discussed above is a precise and simple way of recording the peri-implant soft tissue contours. It can be routinely used to record and transfer the desired emergence profile onto the master models in order to fabricate well contoured, esthetic implant restorations.

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References:

1. Walter F. Biggs and Allen L. Litvak, Jr. Immediate provisional restorations to aid in gingival healing and optimal contours for implant patients. J Prosthet Dent 2001; 86:177-80.
2. Daniel C.T. Macintosh and Mark Sutherland. Method for developing an optimal emergence profile using heat-polymerized provisional restorations for single-tooth implant-supported restorations. J Prosthet Dent 2004; 91:289-92.
3. Avi Donitza. Prosthetic procedures for optimal aesthetics in single tooth implant restorations: A case report. Pract Periodont Aesthet Dent 2000; 12(4): 347-352.
4. Larry C. Breeding et al. Transfer of gingival contours to a master cast. J Prosthet Dent 1996; 75: 341-43.
5. Mariano A. Polack. Simple method of fabricating an impression coping to reproduce peri-implant gingiva on the master cast. J Prosthet Dent 2002; 88: 221-3.
6. Panagiota-Eirini Spyropoulou et al. Restoring implants in the esthetic zone after sculpting and capturing the periimplant tissues in rest position: A clinical report. J Prosthet Dent 2009;102:345-347

Figure 1: Healing abutment in situ

Figure 2: Healing abutment and lab analog embedded in a silicone putty block

Figure 3: Temporary restorative resin (Protemp 4) flowed around the stock impression post attached to the lab analog

 

Figure 4: Customized impression post

Figure 5: Customized impression post in situ

Figure 6: Final restorations in situ on the day of cementation