This patient has decided to have his upper maxillary incisors removed following a significant dental history that includes endodontic treatment, clinical crown lengthening, full coverage restorations and trauma. (Fig. 1)
Certainly, there are several restorative options available for treatment: tooth supported fixed bridge, dental implant supported fixed bridge, individual dental implant supported restorations, removable partial denture and of course – no treatment. When there are several options available, it is really our responsibility to help the patient make the decisions on the options available based on their unique situation and circumstances. Let’s assume, for the sake of discussion, that the patient is interested in a dental implant supported fixed bridge restoration in the anterior maxillary segment. What would you like to know based on what you see in the clinical photo?
A couple thoughts before we discuss the implant supported fixed bridge option...
Fresh extraction sites visible in the photos certainly lead us to the question whether or not the labial plate of bone is intact or fractured for each of the incisors. Will augmentation or grafting be indicated? If so, how will that impact the provisional restoration? What about lip length and lip mobility – particularly as it pertains to gingival display? What characteristics are you looking for in an implant system that could help with the restorative treatment goals?
Back to the dental implant supported fixed bridge – there are several options available. Two dental implants could be placed in each of the lateral incisor positions (7 and 10), or the central incisor positions (8 and 9), or an alternating scenario that includes a lateral incisor position and a central incisor position (7 and 9, for example).
In an article by Correa1, the effect of implant position on the displacement of the prosthetic structure, as well as the displacement of the supporting bone, was studied at forces applicable to the anterior maxilla. The least displacement of the implant supported fixed bridge was with the implants in the central incisor positions – although it appears as if the flexure was shown to be concentrated in the supporting alveolar structures.
Many times we are thinking about the thickness of tissue in a pontic site versus an area with a dental implant supported restoration. Other times a concern arises as to the labio-lingual thickness of bone in the lateral incisor positions or, with the “wagon wheel” effect, if the implants can be placed close enough to the canines to truly be in the lateral incisor position instead of the interproximal space between the laterals and the centrals. (Fig. 2) In other scenarios, dental implants in the central incisor position could be palatally-oriented to a point that could affect cervical contours and speech sounds. In terms of restorative flexibility, where would you like to see the implants placed to facilitate the option for either – natural gingival tissue or prosthetic pink ‘tissue’?
- Correa, et. al. Mechanical behavior of dental implants in different positions in the rehabilitation of the anterior maxilla. Journal of Prosthetic Dentistry 111(4):301-309; 2014.