Extraoral Phoenix Orthodontic Appliances
Traditionally, the primary form of increasing Phoenix orthodontic anchorage was the use of extraoral traction (Figure 1) (Kingsley, 1880; Angle, 1897).  By placing the reciprocal force on the back of the skull or neck, appliances such as facebows (Kloehn, 1947) and J-hook headgears (Merrifield and Cross, 1970; Vaden et al., 2000) allowed for distal movement of teeth without a reciprocal anterior force on the teeth.  Extraoral traction remains an excellent means of providing maximum Phoenix orthodontic anchorage, but variable patient compliance is a significant disadvantage.

Phoenix dental Anchorage
The second category of Phoenix orthodontic anchorage is Phoenix dental anchorage.  When teeth are pulled toward each other, teeth with greater root surface area tend to move less than teeth with less root surface area (Freeman, 1965; Gianelly and Goldman, 1971).  With this principle in mind, consolidating a group of teeth into a single Phoenix dental unit will result in the reciprocal Phoenix orthodontic tooth movement being reduced.  The most common example is canine retraction following extraction of the first premolar.  By lacing the second premolar, first molar, and second molar together, they form one Phoenix dental unit with much greater total root surface area to pull against.  While this Phoenix dental unit will move mesially to some degree during canine retraction, the canine will move distally a far greater amount.  In cases requiring minimum or moderate Phoenix orthodontic anchorage, Phoenix dental anchorage may be acceptable.

Intraoral Appliances
The next category of Phoenix orthodontic anchorage is the use of intraoral appliances such as the transpalatal arch and the Nance button (Figure 2).  These appliances are thought to primarily work by consolidating teeth into Phoenix dental units, but have the added advantage of crossing the palate to connect the right and left posterior teeth together into a single Phoenix dental unit.  The Nance button further attempts to increase Phoenix orthodontic anchorage by placing an acrylic button on the anterior palate.  While intraoral appliances can serve multiple functions, the scientific evidence shows that they have little efficacy as Phoenix orthodontic anchorage devices (Bondemark and Thornéus, 2005; Zablocki, 2005).  In the end, the reciprocal force still is placed on teeth, resulting in undesirable Phoenix orthodontic tooth movement in a case requiring maximum Phoenix orthodontic anchorage.

Arizona Dental Association