Replace 4 missing lower incisors with a 4 unit bridge or with 4 implants?

Thank you for your query
It is difficult to give an answer without seeing X-ray evidence if the space following the loss of these teeth 
Lower incisors are narrow teeth and therefore placing 4 implants can mean that there is insufficient bone between each implant 
Normally it is ideal to have individual crowns but in this situation it is often better to have a 4-unit bridge on 2 implants 
It is better to have a fixed permanent bridge rather than a replaceable bridge or an implant retained denture
I hope this is helpful
Best wishes 
Dr Ian Hallam MBE

Initially, a CT Scan should be taken to confirm that there is adequate amount of bone to place implants in that area.  Assuming there is, two implants would be required to support a 4 unit bridge.  As long as the implants are positioned properly, this can give a very nice result.  You will,however, have to use a floss threader to clean under the bridge with dental floss on a daily basis.  If there is enough space and adequate bone, 4 implants can be placed.  This will feel more natural as each implant can be restored as an individual tooth and you will be able to floss as you would normally without the use of a floss threader.  It will be more costly, but if you can afford it, 4 implants would be better than 2 in my opinion.  A removeable or replaceable partial denture could be used to replace the 4 incisors, but it would not be as comfortable or feel as natural as teeth supported by implants.  Additionally, implants stimulate bone and keep it from resorbing or shrinking.  The gum tissue and bone  under a removeable prosthesis will have no stimulation and will continue to resorb or shrink over the years.  This will eventually cause space under the partial, and it will require replacement in order to keep food from collecting under it.  Replacement of your teeth with implants would be a much better choice.