Let''''s start from the beginning. If you have pain and sensitivity sensation when you are wearing temps, two things may have happened: 1) the temp is not done well and the margin was leaking causing sensitivity. Usually the sensitivity should be slight but not intense. If it does, then the preparation may encroached near the nerve causing undesired reaction. The correct decision should be waiting for the pain and sensitivity going away before cement the final bridge. If after 3 to 4 weeks and the pain is not going away, the tooth required the root canal; 2) the second scenario is also very common. The occlusion on the temp and the final bridge was incorrect. Occlusion is how the top teeth fit into the bottom teeth during functioning or swallowing. If the occlusion is bad, you will experience strong sensitivity, excruciating pain, headache, and the nerve will die shortly. Many times if caught early, the occlusion can be fixed and the symptom will subside with no damage done. In your situation, the final bridge should NOT be cemented immediately but rather the dentist should wait. The solution is now the tooth needed the root canal. I think the dentist should performed the root canal and there may be a charge for it (sometimes, rarely but does happened) a tooth can die due to the bridge preparation). However, I think the bridge should be redone with no charge since no one wants a brand new bridge with a hole.