I've been in dentistry for 20 years and I currently work as a traveling dental professional in my area. Most patients trust the diagnosis from there dentist but I'm here to tell you that every dentist treatment plans differently. Dentists don't get an hourly wage but make money on fixing teeth. Recently, I worked with a dentist who told the patient she had 15 cavities & needed to get them scheduled right away. She was smart enough to ask another dentist in the area for a second opinion. The second dentist only diagnosed 3 cavities. I see dentist treatment planning things all the time just to boost production. If you're unsure about your dentist diagnosis, call another dentist and ask them to give you a second opinion. Usually they will do a free exam for you. This could not only be beneficial to your health but could save you $$$$$$.
Feel free to ask me any dental related questions.