From start to finish the process usually takes 3-6 months and about 4-5 visits. Local anaesthetic is usually required on only 1 or 2 visits; when the implants are placed and perhaps when the implants are exposed following integration (osseointegration) with the jaw bone. The remaining visits are to take impression and fit the implant crowns.
The “teeth in a day” approach to treatment is possible in certain situations although I believe the circumstances have to be ideal.