Sometimes the hygienist and front desk person do not know how to comfortably explain the difference between D1110 vs. D4910, so they opt for the path of least resistance because they're afraid they'll upset or lose the patient. For this reason it is vital that your hygienist and front desk be able to comfortably educate patients on the necessity of regular periodontal maintenance visits, and how that is different from a prophy. This is done by using effective case presentation techniques. Start by role playing with your hygienists to see how well they can educate patients about the differences. It can be a real eye opener.