Thank you for your question. It is difficult to give you a straight forward answer without seeing you as things do sound rather complicated.

From your question it sounds as though your existing crowns are not savable due to lack of bone support. If this is the case when you have the teeth removed there is likely to be insufficient bone to support for implants and also possible problems with providing you with a cosmetically pleasing bridge. A possible way to resolve this would be to carry out a bone graft to increase the amount of bone available. Obviously a comprehensive examination of your problem is required to decide on what options to take.

As to whether to have implants or a bridge there are a number of things to consider. Are the teeth next to the space untouched – and if they are is it a good idea to have them cut to allow a bridge to attach to them? Are they strong enough to support a bridge? Often the cost of a multiple unit bridge is comparable to having implants placed. The great thing about implants is that no damage is done to the adjacent teeth, although at the front of the mouth it can be very demanding to produce a great cosmetic result with implants.

Sorry for the lengthy reply but there are many aspects that you need to consider and you should seek a consultation with a dentist experienced in these matters.

Regards,