THE D2 APPLIANCE TAKES ADVANTAGE OF DECREASED RESISTANCE, MAKING MOVEMENT EASIER AND FASTER.

D2 APPLIANCE IS A MOLAR DISTALIZING APPLIANCE COMPRISED OF TWO SEPARATE COMPONENTS THAT ATTACH WHEN BONDED ON THE TEETH.  THE MOLAR COMPONENT HAS A LARGE, MICROETCHED, EIGHTY GAUGE MESH PAD TO MAXIMIZE BOND STRENGTH.  A FREE-FLOATING BAR COMES ATTACHED TO THE BUCCAL OF THE DISTAL COMPONENT WHICH ALLOWS FOR MOVEMENT IN ALL THREE PLANES AND CUSTOM SIZING TO FIT ALL PATIENTS. 

1. A decrease in resistance for AP movement. Less force is needed to move a buccal segment than an entire arch over the same distance in the same period of time.  This is due to the decreased resistance caused by decreased tooth:bone interface.  As forces decrease, there is less concern for unwanted side effects.  
   
2. Compliance is best early in treatment.  There is often a correlation between length of treatment and compliance. The longer a patient is in appliances that require increased maintenance, the less likely it is for the average patient to comply with those requirements.  Correcting to a Class I occlusion early reduces the need for additional motivation or compliance late in treatment.  
   
3. Hygienic. The easier it is for a patient to maintain good hygiene, the less likely gingival inflammation or areas of decalcification will develop.  The D2 has significantly fewer areas for food/debris to become trapped and is designed to allow easier cleaning than many other Class II appliances. Treatment progresses more easily with healthy teeth and gingiva.  
   
4. Mesial-out molar rotation. Over 80% of upper 1st molars rotate mesial-in during the transition from mixed to permanent dentition costing 2-4mm in arch length. When the maxillary primary second molar is exfoliated, the permanent first molar has space to migrate to the mesial.  As the first molar moves mesially, the buccal segment is prone to advance faster due to the size of the palatal root.  This results in a mesial-in rotation centered around the palatal root. D2 mechanics rotate the molar around the palatal root regaining lost space.  
   
5. Decreased time in braces. The D2 may be used with or without braces as anchorage.  When a lower lingual holding  arch, TAD with button, or overlay retainer with button is used, the amount of time in brackets is diminished significantly because the patient becomes a Class 1 case rather than Class II.  Class II may also be corrected in combination with Invisalign.  
   
6. Simple and Strong. There are only two parts to the appliance. Elastic wear by the patient keeps the two pieces tightly together. It is easily fit chairside saving lab time and expense.  The larger than normal microetched pads provide exceptional bond strength. If breakage should occur, the appliance can be rebonded chairside without lab intervention. The D2 is also unobtrusive and less bulky than most other appliances.  
   
7. Truly Universal. Each appliance fits both the right and left side. In addition, one size truly fits all.  The bar length is adjusted prior to cementation to fit any patient. This dramatically reduces inventory requirements since different sizes do not need to be stocked.   This bar is contoured to the archform with a 10-30 degree bend placed at the molar end to add mesial-out molar rotation.  It is marked and clipped at the appropriate length for the individual patient. The distal component is then bonded.  The anterior component slides onto the end of the bar and is bonded to the cuspid or premolar.    Full-time elastic wear is prescribed from the anterior component to lower molar.  The lower anchorage may consist of lower brackets, a bonded molar button and overlay (or Invisalign), or a bonded molar button and TAD.  
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Patient visits are scheduled 8-12 weeks apart.  Adults may benefit more quickly by bonding maxillary 1st bicuspid to 2nd molar instead of cuspid to first molar.  It is important to consider the amount of resistance and relative anchorage to determine appropriate force.  In general, 1/4” 4oz elastics are sufficient to move teeth when maxillary 2nd molars are not fully erupted. If 2nd molars are fully erupted, 3/16” 4oz may result in better movement. Additional mesial-out molar rotation may be obtained by increasing the bend at the molar end using a three-prong plier at any routine check visit. The appliance is usually worn 4-6 months.  It can also be used in mild Class III cases by bonding the D2 on the lower arch.   Sample Class II case below before Invisalign treatment: Photo on right taken at 2nd visit. Appliance was removed at this appointment and the patient was scanned for start of Invisalign.   Patent is pending.  Questions may be directed to Dr. Todd Dickerson at D2Appliance@gmail.com.