Can a Tooth/crown Be Excluded when Making a Mold?

Do not be concerned!  There is not an impression material on the market with the ability to fracture or break a crown.  You need to include these teeth in the impression to make sure that you get a tight fit with your bleaching tray.  This way you achieve  a nice result with your bleaching.  You may fracture the crown further one day with normal chewing and if this happens the crown would need to be replaced.  Go bleach your teeth and do not worry.

Yes, teeth can easily be blocked out of a custom-made tray.  When a tooth is blocked out, the whitening gel will not flow onto that tooth.  This will be done for teeth with crowns or restorations that can not be whitened.  Best, Dr. Elizabeth Jahanian

They cant really leave out the crowns from the molds cuz then the trays would not stay in very well. Have the trays made and you'll see that they dont affect the crowns at all..

The impression material used to make whitening trays is not very stiff at all. It is highly unlikely that it will further damage your crown.  You exert far more stress on it by everyday chewing and biting. If you are really worried, you can ask you dentist to use some wax or other material to "block-out" the chipped area so the impression material does not "catch" there. But I really think this is not needed.

BTW, this chip may be repairable if you wanted by using porcelain etchant and bonding material. This may hold up well since it is not in a direct load bearing area. However if its not noticeable I would leave it alone or just polish it.

Hope this helps

Dr. T

I have never had a crown chip or break in 12 years of practicing dentistry when taking an impression so I would not really worry about that.  Keep in mind that normal eating and functioning may chip the tooth further thus accelerating the need to have the crowns replaced

While the porcelain on the crown is weakened (it's already chipped...) it is very unlikely that an impression will chip it further.  So I would not worry about that, but would not be surprised to see more chipping in the future.  Also, be forewarned that bleaching your teeth may not give them the same shade as the porcelain crowns.  Unless, that is, the crowns were made to match teeth that had been bleached shortley before the crowns were made.  In that case, bleaching should restore the original color match.

If the porcelain has already chipped from a crown, it will likely chip some more just with regular eating, cleaning, or if you grind your teeth...so plan for its replacement in the future while hoping for the best! As well, you should know in advance that it can be very difficult to whiten surrounding teeth to "match" existing crowns, and at the end of whitening you may not be completely happy with the appearance.  Having said all of this, it is not likely for the porcelain to further chip while making impressions, as the material is usually quite soft and has some flex.

It is possible to block out teeth when making an impression (making a mold), but I wouldn't worry too much about your crown chipping during an impression. Most small nicks don't do anything and I've never had a crown chip or break during an impression in over twenty years in practice. Unfortunately, if the nick in the porcelain on the face of your crown has weakened the rest of the porcelain (tough to predict), more of it may break off at some point and there's not much that can be done to prevent it.