Both upper & lower Essix models are trimmed up as shown in the picture and any anomalies removed with an Ash 5 / 9.
Both upper & lower Essix models are then coated with a plaster separator to prevent the Essix Retainer blank material from 'sticking' to the models.
A Biostar machine is being used here. The picture shows the upper model in position on the platform and the Essix retainer blank (1mm thickness) in position prior to heating. N.B. If using a round blank, then the dimentions are: - 1mm thickness by 125mm round.
The heating element is then moved over the Essix retainer blank.
The Biostar machine will alert you when to close the chamber over the upper model and the locking arm should be moved in to position.
The chamber will be held under air pressure during the cooling phase.
The Biostar machine will again alert you when to evacuate the chamber.
At this stage the excess blank material needs to be removed. It is often easier to use scissors to make the initial cut up to the palatal / lingual area.
A bur is then used to cut through the Essix material. This should be done to approximately 7mm in the palatal / lingual area and 3mm away from the gingival margins in the buccal and labial areas.
This picture shows the upper and lower Essix blanks removed from their models and ready for trimming to the design specified by the clinician.
For this stage of the trimming, a metal acrylic bur is used.
This particular design required the Essix retainers to extend around the distal area of the upper molar teeth.
Extends along the gingival margins and into the palate a distance of 5-6mm.
See final pictures for further guidance.
This picture shows a second bur been used to remove any small particles from the periphery of the retainer caused by the roughness of the previous metal acrylic bur.
N.B. This stage may or may not be necessary prior to polishing on the lathe using pumice.
The periphery of both upper and lower retainers are then lightly pumiced on a lathe.
N.B. Remember it is only the periphery of the retainers that should be pumiced and not the whole surface of the appliance.
The retainers are then rinsed free of pumice using cold water.
N.B. Hot water is not used to rinse the retainers because this would heat the material of the retainers and risk distortion of the appliance.
These set of pictures show the finished upper & lower retainers in position on their models.
Note the position of the finished periphery-approximately 1mm or less away from the gingival margins. (and this continues along the buccal section).
Above, the palatal view of the upper retainer in position on its model. Again note the position of the finished periphery-approximately 5-6mm away from the gingival margins.
