10 days after extraction, my dentist twisted 2 sharp tops off attached bone poking up into my gum on the cheek side of my healing socket. After extraction, bleeding stopped as expected, and I had no dry socket symptoms, but the sharp points caused pain and inflammation until removed. However, the dentist said the site was healing more slowly than expected after 10 days. He said if healing hadn't improved significantly by day 17 then he might need to intervene. What are some possible causes of this slow healing, and what interventions can dentists use to speed the healing process?