David Shen convinced me to wear Invisalign to close the gaps between my teeth. Since I am not a professional I listened to his advice. After $ 7,000-worth of treatment, my jaws were hurting, the gaps were not closed, there was overbite so nothing got better. Initial exam was carried out by David Shen but after the first treatment some less experienced dental personnel(I am not sure if they were dentists) worked on my teeth. And he wanted to charge me extra money to fix the failed treatment.