Chipped tooth #18, has huge filling already

[Dental Impatient]

Tooth 18 has a huge filling in it and I chipped off a huge chunk of enamel from the top. I know it's going to need a crown, that's a given. Here are my concerns.

1. I'm very concerned that when he gets in there to remove the filling, the tooth is going to crack and need to be pulled. I know this is a risk regardless. Tooth 17 was pulled a long time ago, and 19 was pulled and I have a dental implant there. If I do have to have 18 pulled, will the implant prevent teeth 20+ from shifting?

2. Should I go ahead and just get it root canaled? I'm reasonably certain that there's so much filling in there that the root will be exposed when it gets opened. Wondering if it'd be better to just see my endodontist and get that knocked out.

Thanks in advance.

 

[MattKW]

1. Taking out the filling won't cause the tooth to crack. But if I see a large cracked filling like that, I worry that the crack may also already be present in the tooth underneath. You have to take out the filling to see, and then you have to assess if the tooth is still suitable for a crown.
   The implant will prevent other teeth from moving.
2. If you have no pain, then the tooth will be a better base for a crown if it hasn't had an RCT, so try to avoid an RCT. The first step is to get out the filling and assess is you will be able to save it with a crown; an RCT is a secondary consideration. If the tooth will be too weak to support a crown after an RCT, then I don't start an RCT. What's the point in putting a new engine in a car with a crapped out chassis?