The esthetic management of multiple missing teeth is one of the most challenging occurrences restorative dentists are presented with. It's one thing to replace a single missing tooth with a pontic or an implant, but replacing multiple missing anterior teeth is an entirely different scenario when it comes to esthetic predictability. A simplified way of thinking about this problem is to realize there are four different scenarios that a patient can possibly present with that needs multiple teeth replaced in the anterior, and the prognosis for the esthetic outcome is very different for each scenario.
1. Needing extractions but with good bone and soft tissue. This is by far the most predictable presentation since the teeth needing extraction are still present, and there is no bone loss. Even though this is the possibility with the greatest chance for a very good esthetic result, it is unlikely you'll get to keep the gingival esthetics exactly the same. That aside, this possibility gives us the best shot of successfully achieving an esthetic result in the long run.
2. Needing extractions but with poor bone and soft tissue. Although this presentation isn't the most ideal, there are still many opportunities to get a highly esthetic result. If the teeth are still present, one opportunity is to consider orthodontic extrusion by slowly bringing the teeth down along with the bone and gingiva. If the bone level is poor, it is difficult to ever get it as good as the first scenario above, but the teeth being present does give more options than if they are already missing.
3. Missing teeth but with good ridge. This presentation is highly effected by the bone level prior to tooth loss, and also how long the teeth have been missing. We know that following tooth loss the bone goes through significant remodeling, both in the width of the ridge, and also the vertical height of the ridge. In addition the bony scallop for the facial to interproximal starts to flatten out, making it very difficult to achieve an excellent gingival scallop if implants are used.
Having said that, advances in bone grafting have made this presentation more predictable in outcome than it used to be, but not typically equal to having the teeth still present and needing extraction. Typically the final result will be decent, but may have a very flat periodontium and very long contact.
4. Missing teeth with a deficient ridge. This is the most challenging presentation by far. The ridge deficiency can be caused by multiple things, including trauma and infection. The real challenge is what we are capable of in terms of bone-grafting and soft-tissue grafting. When bone needs to be grown vertically it can be an extremely challenging task to accomplish.
According to the literature, there really isn't any general consensus on how to best grow bone vertically, and most methods only yield a growth of 2-3mm at best. It is for these reasons that often this patient may do better with prosthetic soft tissue replacement, pink porcelain, pink composite, or pink acrylic, rather than multiple heroic surgeries. In fact if the high lip line doesn't expose the ridge, using prosthetic soft tissue can be highly esthetic and predictable.