Dental The first reaction that takes place when an orthodontist attempts active tooth movement with a removable appliance is: A Pressure and tension zones form in the periodontal ligament B Force is applied on the tooth C Osteoclasts create undermining resorption D Tooth moves by direct resorption 💡 Explanation The first reaction that takes place when an orthodontist attempts active tooth movement with a removable appliance is: ✓ Correct Answer: A. Pressure and tension zones form in the periodontal ligament