Is getting an implant on my upper 2nd molar possible and/or worth it?

It depends on whether you have a second molar in the lower jaw to oppose the missing tooth and potential implant. If you do have one on the bottom, you should consider the implant. As well, it depends as to whether you are missing any other teeth and need the support. Without the 2nd molar implant, you are now placing excessive force on the first molar in front of the space. If that tooth has a root canal or a large filling, this may cause the tooth to fracture over time. You may also experience teeth drifting into the space and compromising your bite. See a prosthodontist for a 2nd opinion and think about it. 

if u r considering smile in that implant is not required but considering function in that it [ implant /crown] is required. it will prevent supra eruption of opposite tooth, tilting of neighbouring teeth etc. 

There could be a few reasons your dentist may not suggest an implant. The first being opposing occlusion; if you don't have a second molar in your lower jaw opposing where your upper second molar used to be, then placing an implant would serve you no real function, as you would not be chewing against anything. The other reason is that maybe you have very little bone to support the implant, as its possible the floor of your sinus may be very low. If that is the case, however, you could have a grafting procedure done to lift the floor of the sinus and create space for implant placement. If you have an opposing tooth to bite on, I would be inclined to suggest replacement with an implant so that you could regain your function. In any case, I would seek another opinion from a different office/practitioner. Hope that helps! 

Hello,Possible reason for the dentist denying an implant in that area could be the absence of an opposing tooth, which would make the entire procedure pointless from functional point of view. You can ask them a possible reason for the dismissal. If smile is your concern than the second molar won't play a good role in the same.