Hi Kay welcome and thanks for your question.  A small number of people taking a Bisphosphonate, may develop a problem with bone healing after an extraction.  If you have periodontal disease (residing gums) or other gum disorders, you may be more prone to this.   Some dentist and oral surgeons will put you on a drug holiday before they extract teeth from patients who've taken the drug for some time.  Ask your Dentist if this is the reason and if you should go on a drug holiday before the extraction, and how long they recommend you do this.   Good luck...  If you have another question just re-post.