As I have mentioned in previous articles, there are multiple treatment options available for managing patients with missing lateral incisors. Although single tooth implants are typically our primary choice, other treatment options that may be considered include canine substitution or some form of a tooth supported fixed partial denture.
Ideally, we want to choose the most conservative treatment option that satisfies the esthetic and functional goals. Typically, the most conservative treatment option is a single tooth implant. However, not every patient is willing to undergo the necessary treatment to enable a single tooth implant to be placed. For whatever reason, if a single tooth implant cannot be used, some form of tooth-supported restoration will be required, of which one option is a cantilevered fixed partial denture.
The patient in the photo had congenitally missing lateral incisors and had implants placed in both #7 and #10 sites that failed to integrate. The implants were subsequently removed and the areas augmented. Implants were again placed only to have the #7 fixture fail to integrate a second time. At this point she was seen in my office with two main concerns; she didn’t like the esthetics of the implant restoration of #10 and wanted the #7 area restored. Her stipulation with the #7 site was that “no other surgery be performed.”
With this in mind, the restoration in the #7 area would have to be a “tooth supported.” The most conservative tooth supported restoration would be a resin bonded fixed partial denture. Unfortunately, the excessive proclination of her anterior teeth are a contraindication for this type of treatment option. After a resin bonded FPD, the next most conservative tooth supported restoration is a “cantilevered” fixed partial denture.
Since her teeth were esthetically pleasing to begin with, the cantilevered restoration could be designed as partial coverage (leaving the facial of the abutment tooth untouched). In order to increase the retention of the restoration, a “pin-ledge” design was utilized. Given its size and thickness, the canine was chosen as the abutment. Utilizing the VIP pin kit from Whaledent, 3mm deep pinholes were placed in the cingulum area and on the distal palatal. The most challenging part about the preparation isn’t dropping the pins, but rather placing the groove on the mesial. If the groove is placed too far towards the facial, you risk the abutment preparation being “seen” from the anterior and hence negatively impacting the esthetics.
Plastic impression pins were picked up in the final impression and the model was poured in stone. Gold was chosen as the material for the canine abutment along with a traditional metal ceramic crown for the lateral. The definitive restoration was bonded in place with resin cement. With regard to managing the occlusion, although you can have a centric contact on the cantilever, it is important that all excursive contacts be removed. Controlling the lateral forces on the cantilever is crucial for the long-term predictability of the restoration.