Appliance Design for Successful Removable Orthodontics – Part 4

Summary of Tips and Techniques

Dr. Rob Veis

In this final article in our series on successful appliance design, we’ll sum some of the critical aspects of our discussions.

  1. Prior to beginning any Appliance Therapy, always collect detailed records. These should include a complete medical and dental history, periodontal screening, complete dental charting, all necessary x-rays (FMX, Panorex, Lateral Ceph, Tomograms), photographs, study models, and working casts.
  2. Diagnose and treatment plan the case – Take the time to closely evaluate your records. Next, sequence out your treatment step by step.
  3. Evaluate your ability to treat (case selection) — It is essential to understand your own limitations. Not everyone feels comfortable performing endodontic therapy on second molars. The same can be said about Appliance Therapy. If you are uncomfortable treating a problem, don’t hesitate to refer it to a specialist.
  4. Every appliance in the Appliance Therapy textbook has been given an appliance number. It will always be tempting to simply write this number down and leave the rest of the prescription blank. DO NOT DO THIS. It is very rare to be able to select an appliance out of the book without having to do some small modification in its design. At bare minimum, you will need to indicate which teeth need to be clasped or banded. Therefore PLEASE FILL OUT THE PRESCRIPTION COMPLETELY.
  5. Check your models very carefully for accuracy and completeness. Large air holes and stone bubbles are not acceptable. The models should articulate properly and not rock due to stone bubbles on the occlusal surfaces of the posterior teeth.
  6. When sending a construction bite, check to see that the models fit into the bite completely and accurately prior to shipping. Do not ship the models in occlusion or with the construction bite between the teeth.
  7. Often, when in maximum intercuspation, the lower incisors are too tightly coupled with the lingual of the upper incisors to allow needed tooth movement. Check to see that adequate overbite and overjet are present prior to designing an appliance to align lower anteriors.
  8. Carefully consider the age and responsibility level of your younger patients. Are they responsible enough to properly care for a removable appliance? Will they be losing it constantly? Consider a fixed approach in these situations.
  9. Always design active components first and retention second. This will help ensure retention is adequate and in the proper location. Note that the design sheet has been organized so the active components will be designed first.
  10. It is best to always try to design an appliance with no occlusal interference. Sometimes the patient’s free-way space will be enough to allow for comfortable appliance wear. However, occlusal interference from clasping may not always be avoidable. When clasp interference is a problem, a thin, balanced, occlusal bite plane may be required.
  11. Proper treatment sequencing usually entails: First, correct any crowding (lateral and anterior/posterior). Then correct the jaw relationship (anterior / posterior and vertical). Finally, align the teeth. A common problem is trying to accomplish too much with one appliance. More than one appliance is often needed to complete treatment.
  12. Be sure that a tooth to be clasped or banded is erupted sufficiently for proper retention. If a tooth is not fully erupted you may consider creating retention by placing a buccal undercut with a composite ledge. A “C” clasp can then be used to engage the undercut.

The goal of all of our continuing series of articles is to move you forward in your educational process towards becoming proficient in Appliance Therapy. Properly designing an appliance simply is not as easy as it looks. The key to success is practice, practice, practice. If you follow the steps outlined in this series of articles on appliance design, I know that your rate of success will occur faster.