ACCO or Acrylic Cervical Occipital Anchorage is an appliance in field of
orthodontics which is used for
distalization of
maxillary molar
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
s. This appliance is a removable type of appliance which was developed by
Herbert I. Margolis. This appliance is intended to be worn 24 hours a day except during meals. It is one of the few removable appliances made for distalization of molars and thus require patient compliance for the treatment to be successful.
Components
* Palatal Acrylic with bite plate
* Modified Adams clasps on
first premolars
* Labial bow across
incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s
* Finger springs against first molars
In this appliance, the fingers springs are the main component which act against the 1st molars to move them distally. These springs apply about 100 to 125g of force to the molars after they are activated posteriorly. The original appliance developed by Margolis included helices next to the laterals and canines for a straight pull or Northwest headgear tubes to be inserted. This appliance is specifically indicated for adolescents or pre-adolescents patients who are in mixed dentition and are very compliant.
Management of appliance includes measuring overjet every appointment to measure the anchorage loss of the appliance.
[{{Cite web, url=https://www.jco-online.com/archive/article-view.aspx?year=1969&month=09&articlenum=461, title=The ACCO Appliance - Journal of Clinical Orthodontics, website=www.jco-online.com, access-date=2016-11-20]
Advantages
* Patient friendly
* Continuous forces to the teeth
* Possible asymmetric distalization of the molars
Disadvantages
* Tipping of molar teeth (instead of translation)
* Loss of anchorage where the overjet increases
Dietz et al.
recommended that to avoid tipping of molar teeth, a high pull
headgear can be used in conjunction with this appliance. As the ACCO appliance will move the crown of molar distally, headgear will act to move the molar roots distally. In order to avoid loss of anchorage, they also recommended to achieve "overcorrection" of the molar distalization by 2mm or more. Anchorage loss occurs as anterior teeth move mesially, shown by 2mm increase in overjet and also 1st molars moving mesially. The authors also stated that presence of 2nd molars can exacerbate the loss of anchorage. Therefore, addition of finger springs can be added to the 2nd molars to move them distally also.
See also
*
List of Orthodontic Functional Appliances
This is a comprehensive list of functional appliances that are used in the field of orthodontics. The functional appliances can be divided into fixed and removable. The fixed functional appliances have to be bonded to the teeth by an orthodontist ...
*
List of palatal expanders
This article lists different types of expanders that are available for the process of palatal expansion in the field of orthodontics. There can be many types of transverse dimension appliances. These appliances can be used to achieve expansion in t ...
*
Molar distalization
*
Pendulum appliance
*
Herbert I. Margolis
References
Orthodontic appliances