 Some dentists may decide to temporarily fill the canal with calcium hydroxide paste in order to thoroughly sterilize the site.This strong base is left in place for a week or more to disinfect and reduce inflammation in surrounding tissue, requiring the patient to return for a second or third visit to complete the procedure.There appears to be no benefit from this multi-visit option, however, and single-visit procedures actually show better (though not statistically significant) patient outcomes than multi-visit ones.