Upper pre-molars present as a special case when they require endodontic treatment. They are skinny, weak teeth in their virgin form, and once a marginal ridge is lost, or endodontic access is performed, their resistance to fracture drops significantly.
My opinion on these teeth is that the restorative needs trump the endodontic needs in the majority of cases. Endodontists I know who have conducted long term follow ups of their cases find this tooth to be in the higher failure category, and the failure is most commonly fracture of the tooth. There’s many ways to skin a cat, but this is how I handled this case. The only dentine removed was directly over the pulp horns. I’m still recommending an onlay/crown. I’m interested to hear how you would restore this in your practice.
The only dentine removed was that directly over the pulp horn. Conservation of pericervical dentine and the dentine connecting the mesial and distal parts of the tooth assists in maintaining strength.