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Fabrication of a Soft Lower Bite Raising Splint

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The following describes one way to fabricate a Soft Lower Bite Raising Splint.

All photographs, text and appliance fabrication by Mr. Andrew Tinkler at the Orthodontic / Maxillofacial Laboratory—Royal Lancaster Infirmary.


The model is trimmed as shown. The model is reduced to these dimensions to ensure a decent thickness of the EVA blank material will cover the whole dental arch. N.B. If the model was left too ‘tall’, then the EVA blank material would be stretched and thinned out over the incisal / occlusal areas of the teeth.
The lower model is prepared by removing any anomalies, using an Ash 5 / 9 or similar and blocking out any major undercuts if necessary.

The picture shows the laboratory work sheet and the cast lower model prior to fabrication of the splint.

The model is then Cold Mould Sealed in the usual way.

A Bio Star machine is been used here. The picture shows the model in position and EVA blank in position. A 3mm blank is used for this particular soft lower bite raising splint.

The heating element is then moved over the EVA blank.

The bio Star machine will alert us when to close the chamber over the lower model. The locking arm should then be moved in to position. The chamber will be held under an air pressure during the cooling phase.

The Bio Star machine will again alert us when to evacuate the chamber. The formed blank and model can then be removed from the machine.

The excess blank material can be removed using scissors or using a scalpel heated in a Bunsen Burner flame.

The excess blank material can be removed using scissors or using a scalpel heated in a Bunsen Burner flame.

The periphery of the appliance is then trimmed using a rough bur, removing any sharp edges. Both lingual and labial areas are trimmed to the gingival margins.

The periphery is then smoothed using a polishing bur.

This picture shows the final ‘glossing’ of the splint. In this process, the periphery of the appliance is flamed (using a pen flame or similar) and quenched in water to prevent distortion. Quenching of the appliance during the flaming process. Please note that the flaming and quenching is done in small stages. For example, you should flame about 1—2 inches of the periphery of the appliance and then quench it. This is repeated until a ‘gloss’ is attained over the whole periphery.

The finished Soft Lower Bite Raising Splint. Please note that the finishing line of the periphery of the splint runs (in a straight line) along the lowest points of each gingival margin.
The splint ends half way across the second molars. This is mainly due to concerns of the in-accuracy of the impression in this area. Also some clinicians believe it will not ‘gag the bite open’ as much.


For further information contact : -

  • Mr. Andrew Tinkler. LOTA.
  • Maxillofacial Laboratory,
  • Royal Lancaster Infirmary,
  • Lancaster .
  • LA1 4RP.

Peer assessed by: -

  • Mr. P. Mason. LOTA
  • Chief Orthodontic & Maxillofacial Technician.
  • Kettering General Hospital .