4 weeks ago our 3 1/2 year old boy took a tumble that resulted in
damage to his upper central incisors...his two front teeth. He has
been seen by a dentist several times. Both teeth are discoloring.
Today when we went to the dentist, the dentist concluded that the
blood supply had been cut off on one of the teeth. In addition the gum
around this tooth had some puss and redness. He told us that we should
proceed with an extraction on the one tooth but wait and see on the
other. The question: Is extraction the recommended route for this
situation or is it better to try to "save" the tooth and go with a
root canal? What does the research say on this subject? In this
pediatric situation what are the upsides and downsides of extraction
vs root canal?

(I am not a dentist.)

I would go for extraction as
(1) the deciduous teeth will be lost anyway
(2) extraction of deciduous teeth should be fairly quick and easy.
Root canal work is traumatic enough for adults, but for a small child
could be extremely distressing and possibly give rise to long-term
'dentophobia'

AFAIK the main caveat against extraction of deciduous teeth is whether
the root cavity is sufficiently well formed to prevent the permanent
teeth being misaligned as they form. Extraction may increase the
likelihood of some orthodontic work later.

Owain