I have started some preliminary research and it seems the procedure we are looking at is called "vital pulpotomy with pulp capping". It is outlined on this vet website
You can access the site as a vet, by contacting them for a password or something.... I have also written an email to them asking if they are willing to work via correspondence with us... I am not sure how they seal up the one that is fractured all the way up though - wouldn't the risk of infection still be there?
Here is what they had to say about Summer's type of injury -
I spoke to a vet tech friend in the US and she said most
likely we will get the best outcome if you can try and contact
a vet directly? She said they are more likely to help rather
than if I wrote to them. I will continue doing my homework and
E-MAIL REPLY FROM DR SING DATED MAY 10, 2012
It was great to meet you in person after our e-mail correspondence regarding the rescue group who had a stray dog with tick fever of Babesia gibsoni that your first vet said that imidocarb would not be effective and only the use of the expensive Atovaquone and azithromycin would cure this dog. You got the dog treated by a sponsor of an online request for help and the second vet had successfully treated it with imidocarb with two injections and the dog is now healthy.
Thank you for your detailed research on the dental procedures for your naughty young Retriever who has fractured both upper pre-molars 4.
Singapore does not have a veterinary dental specialist and your research on procedures will be most helpful and useful for Singapore dogs with similar problems. Dental extraction has been advised by vets you had consulted. Your dog's right upper premolar is definitely sensitive as the pulp is exposed partially.
You live in a golden age where internet info is easily available if a person takes the time and trouble to research on a specific medical or surgical problem. We will plan what to do with your Golden Retriever's fractured premolars within 14 days and after you have completed your research. Thank you for doing the research.