M. Andrew Atwood, DDS

I wouldn't replace it unless it has failed. That can happen if the porcelain breaks, or you get a cavity under it. If it has broken, consider going with an alternative restoration like an implant. An implant crown can be constructed out of a stronger material like emax, and if the emax breaks, then you are only stuck with the replacement of 1 unit of porcelain instead of 3 or more.

Also to consider, if the bridge fails, and 1 or 2 of the adjacent teeth can still be salvaged, then the implant won't cost much more than the bridge anyway.

I almost always recommend going with the implant over a bridge. In the case where aesthetics are concerned, a bridge can be more predictable. As for longevity, I believe the implant will likely win. Most implant decisions boil down to cost, so if you can afford it (and wait for the tooth to come) I would say go with the implant.

Everything has a life expectancy and can break and wear down. It is important to know that, but what can you do about it? I feel like it is best most of the time to conserve tooth structure and doing a crown doesn't do that. If the veneer is going to remove a significant amount of tooth structure then a 3/4 crown or full crown may be acceptable too. The only reason to do a full crown is if they are not confident about the bond and need the mechanical retention it offers, or that the bite is in a spot where the porcelain of a veneer risks being damaged. 

10 years is a good guess, but nobody knows for sure. If the veneer is bonded to a lot of enamel that can increase it's odds of lasting long.

I would just wait. Peroxides are capable of mutating genes, although they would have to get deep into the tissue and then into the blood stream, and then to the baby to affect the baby's health. I doubt that it is significantly absorbed to do that, but it is wise to just wait and get them whitened first thing when your baby is born.

I have not done many CEREC crowns, but there are limitations with them. The top reasons I would chose a lab fabricated crown have to do mostly with aesthetics. If the tooth is in the front, and it is very critical that it matches, there is no better way to go than with a ceramist that can build in the visual details into their crowns. A skilled dentist can sometimes stain the crown's surface to match closely, so it can still be matched.

In the hands of a skilled and attentive dentist, the CEREC tool can perform just as well, and you can expect a long lasting, quality restoration. Be sure to ask for an emax crown material for back teeth since that will be the strongest.