Functional Appliances control and direct orthopaedic and muscular forces in an effort to prevent or correct malocclusion.

They are designed to influence the growth and development of the facial skeleton in a vertical plane, horizontal plane or both.


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Functional Overview

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Browse our range of functional appliances below:


The twinblock appliance is suitable for treating a wide range of malocclusions to achieve sagittal and vertical correction of Class II Div i, Class II Div ii, and Class III malocclusions.

The appliance exhibits distinct advantages for arch development, deep overbite correction and mandibular re-positioning.

Advancement screws can also be added into the upper appliance to increase the protrusion of the mandible.


This activator transmits functional muscle forces to the teeth. These forces are dependent on the mandible to return to its normal rest position; the basic activators reposition the mandible forward and open in relation to the maxilla.

This altered functional relationship between the arches produces changes in the musculature and bony structures.

The teeth contact the acrylic of the activator and move through intermittent forces generated from this pressure. Notice the facets are trimmed to allow directional pressure to be applied.


This activator can be used across a broad spectrum of Class II cases as an interceptive device. Problems which would be regarded as contra-indications to the use of the Andresen device, such as severe Class II skeletal pattern, crowding, absence of teeth or local tooth mal-positioning can still be treated using this interceptive appliance.


This appliance promotes the correction of muscular problems in the oral facial complex which can contribute to malocclusions. This appliance can be used throughout the mixed dentition stage of development, as it does not depend on these teeth for retention.

Medium Opening Activator

This appliance restrains the vertical and sagittal forward growth of the maxilla and maxillary dentition, and allows freedom of eruption to the lower buccal segments which will translate a Class II Div i incisor relationship into a Class I relationship with reduced overjet and overbite.

The Frankel Family of Functional Appliances

These appliances are in essence exercise appliances and by retaining the facial muscles and muscles of mastication to occupy new positions, the mandible and maxilla will be influenced to grow into correct positions. There are three main types of the appliance which incorporate a variety of modifications, i.e. FR1, Fr2 and FR3.

The appliances which are in common use are the FR1, for the treatment of Class II Div i mal-occlusions and the FR2, for the treatment of Class III malocclusions. The FR2 is used for the treatment of Class II Div ii malocclusions and by some practitioners for Class II Div i malocclusions.

C.O.F.F. (Clip On Fixed Functional)

This fixed twinblock system can only be removed by the practitioner not the patient so the problem of non-compliance is avoided. The types of case where the appliance can be used are Class II Div i malocclusions, Class II Div ii malocclusions and Class I cases where there has been loss of anchorage resulting in Class II molar relationship.