Mara
Appliance Purpose / Function:
This appliance is often used as a class II bit correction by using independent elbows that engage with the lower buccal cams to advance the lower mandible into a class I position. Shims ranging from 1 to 4 mm may be used to adjust bite advancement and midline alignment.
Appliance Components:
(2) (upper) Elbows
(2) (lower) Cams
(4) Arch wire tubes
(1) Lower Lingual Holding Arch .040
(2) Lower Bicuspid rest .036
(1) Upper Trans Palatal Arch .040
(2) .036 Ball clasp
(2) Elastic loops.
(2) 2mm Shims
(2) Elbow tubes
Appliance Fabrication Standards:
WIRE STANDARDS:
TPA-
- Wire must be contoured 1-2 mm away from tissue
- A 5-7mm omega loop is to be bent in the palate pointing towards the anterior unless otherwise specified by Dr.
- Wire must contact the bands at the mesial portion of the lingual 1/3 third and run to distal to allow for a solder joint
LLHA-
- Wire must contact all anterior teeth on the lingual surface at or below the cingulum except in cases of extreme crowding, in which case only the most lingually positioned teeth should be contacted
- Technician should form this portion into as smooth an arch form as possible avoiding sharp bends
- Posterior teeth must be contacted just above the gingival margin on the lingual surface
- Care must be taken to avoid blocking any teeth in the process of eruption
- A slight tuck must be made into the embrasure between the 2nd bicuspid and first molar when 2nd bicuspids are present
- Wire must lie against middle 1/3 of lingual surface of band
Bite placement-
- Set bit to requested advancement and index bite by marking a line on both buccal sides.
- Mark single line on anterior for midline indexing.
Spot well appliance-
- All attachments and electrodes must be free and clear of any oxidation.
- All attachments are spot welded as a means to temporary place all attachments until soldering any movement or adjustments of any attachments must be followed with and additional spot to prevent movement.
- Attachments might be moved several times until proper placement and function of appliance is achieved.
Upper Arch wire tubes
- Place arch wire tube in ideal position mesial and distal to tooth insuring proper room form placement of elbow tubes to prevent interference with lower arch.
- Insure that the arch wire tube is level with occlusal plane.
Lower arch wire tubes –
- Referencing the upper arch wire tube place arch mesial opening of the lower arch wire tube equal to the position of the mesial opening of the upper arch wire tube ensuring proper room for placement of cams to prevent interference with upper arch.
Lower Cams-
- Place cams three mm mesial of the mesial of arch wire tube placing the cam parallel buccal plane.
Upper Elbow Tubes-
- Place elbow tubes .5mm from crown with he mesial of the elbow tube flush with the mesial of the mesial of the arch wire tube keeping the occlusal of the tube parallel with the occlusal plain.
Elbow Camp placement adjustment and alignment-
- Place models together.
- Confirm that all three indexing lines are aligning.
- Adjust lower cams mesial or distal till bite alignment is correct as indicted on the indexing lines.
- Adjust cams and elbows to ensure no interference and or binding or locking with lower arch wire tubes.
- Place models into extrusion to ensure that elbows do not jump cams. Elbows should have 2 mm of clearance from the mesial of the cam.