David M. Schertzer, DDS

If you are concerned about the implant healing I would recommend you return to the surgeon that placed the implant for evaluation.  Typically they have already talked with the implant patient about returning for reeval during certain benchmark days, such as a 4 week reeval and then at 3/4 months. 

I would recommend you to see an orthodontist.  They would be more familiar with how to deal with difficult situations like this.  

Sorry to here you are having difficulty with your crowns.  eMax crowns are not so much designed to “block out” the underlying discoloration of the tooth but to compensate for the discoloration internally.  This is why a lab needs a “stump shade” of the prepared tooth so they can compensate for the discoloration.  If there is still an issue with the dark underlying tooth discoloring the final eMax crowns there might be a need to switch to a different type of crown (such as a porcelain fused to zirconia) that would actually block out the tooth discoloration and then correct the shade to what you desire.  

The other issue with leaking under the crown could happen with the incorrect cement or not silinating the internal of the eMax crown prior to cementing.  I have never used BlockOut cement and am not confident on its application.  If it is a veneer cement then it is most likely light curable or dual cure and there is a possibility that the cement is not fully cured through a thicker eMax crown. 

If the underlying tooth was untouched with a bur and only etched then the dentist should be able to remove with minimal to no damage.  If the dentist beveled the tooth to help blend in the bonding and give it more surface area to bind to for strength then the tooth was affected and may need bonding to restore the contour. 

If the bonding is causing discomfort when eating it may just simply need a bite adjustment to correct the issue.  However, if you feel the binding is difficult to clean under then you should bring this to your dentists attention. 

This dark spot is exposure of the underlying metal support for the crown.  This usually happens when there is inadequate space for the crown and during adjustment of the bite the porcelain was removed to correct the occlusion.  

Easy bleeding and puffy red gums are definitely a sign of inflammation.  The inflammation could be caused be one or several factors:

1.  Crown overhang or open margin

2.  Excess cement which was not removed

3.  Plaque or calculus accumulation 

4.  Food impaction from light or open contact between the teeth. 

5.  Allergy to the crown or cement 

I would return to your dentist with your concerns

The only way to fix the crown is to return to your dentist and have it replaced with a new crown.  

Redness is a sign of inflammation and is never desired around any dental restoration.  I cannot tell exactly what was done but I would recommend returning to your dentist for evaluation. 

After a root canal, the tooth can become brittle as the blood supply was removed in the process; brittle things break or crack.  The standard of care is anywhere from coverage of the cusps to a full crown.  One dentist performed the full crown and it sounds like the other dentist did an onlay to support and cover the cusps.  Both dentists met the standard of care as far as functionability and strength.  The tooth with the onlay may have had enough tooth structure that your new dentist decided it best to retain as much of the natural tooth as possible. 

I don't see a downside to rebonding the teeth, especially if it was already done previously and you were happy with the results.