the trial dentures
- Artificial teeth set in wax to the jaw registration
- The jaw registration provides the vertical and horizontal relationships of the maxilla and mandible
information required to set teeth
The position of the teeth relative to:
- The residual alveolar ridges
- Horizontal position
- Vertical position
Casts mounted in Retruded Contact Position (RCP) on an articulator using information measured from the pt
- OVD
- centre line
- canine line
- 3D template (occlusal rims trimmed by dentist to support lips, tngue and cheeks)
occlusal vertical dimension
distance between the jaws with teeth in occlusion
centre line
- Centre of the patients mouth (symmetrical with face)
canine line
(line extended from the inner canthus of the eye)
methods of transferring information from occlusal rims to casts (6)
- Take a putty register of the anterior contour
- Use anatomical landmarks to assist tooth position
- Use an Alma case to assist tooth position
- Take an impression of the patient’s existing denture / pour cast
- Ask the patient for a photograph when they had their natural teeth
- Take an impression of family members dentition if appropriate
what to assess about tooth position at trial denture stage (5)
- Aesthetics
- Lip support
- Speech
- Occlusal plane
- Check centric relation
prescription card for trial dentures
in addition to instructions to the technician regarding this stage, the reverse of the card must be completed.
how to transfer centre line data
- The central incisor teeth are set on either side of the centre line
- The central occlusal plane indicates where the incisal level of the tooth will be
- If the blocks have been trimmed supporting the lips – the angle to which the teeth should be set is indicated
importance of occlusal rims in data transfer (6)
- The patient’s centre line – the centre of the mouth/face
- The central incisor plane
- The occlusal plane ( the central incisors are at a different level to the laterals and canines.
- The extent of the patient’s smile line (lip line)
- The canine line (buccal corridor)
- A 3D template to set anterior teeth – providing the occlusal rims are trimmed correctly.
The technician can transfer these lines onto the surface of the casts and plaster mounting
recording the occlusal plane
The centre line is extended onto the surface of the upper and lower cast.
Dividers set at an arbitrary value are used to record the position of the occlusal plane. It is important to record this value.
occlusal plane a.k.a
central incisal plane
how to use he incisive papilla in data transfer
- Central line
- Labial surface of central incisors
- Centre of canine
A guide to the position of anterior teeth is the taken from the distal of the papilla. The labial aspect of the central incisors is approximately 10 mm from this point.
This is an indicator only.
What does the measurement depend on?
- A line extended horizontally from the distal of the incisive papilla at right angles to the median saggittal plane will indicate the position of the centre of the canine.
data transfer information for setting posterior teeth
The line is transferred to the artwork of the cast to display the ridge contour when the base is covering the ridge.
Landmarks can also be used to assist the positioning of posterior teeth.
- Although this is dealt with in more detail elsewhere – the position of the centre of the lower ridge is marked as shown.
In addition, the contour of the ridge is drawn onto the wall of the cast.
An indicator for the height of the occlusal plane can be taken from the position of the retro-molar pad – the occlusal plane should not be above the retro-molar pad. The tongue should be above the level of the occlusal plane to control food bolas on the surface of the teeth
tongue position relative to occlusal plane
should be above the level of the occlusal plane to control food bolas on the surface of the teeth
occlusal plane position relative to retromolar pad
the occlusal plane should not be above the retro-molar pad.
the Alma gauge
- can be used on the upper or lower denture or with occlusal rims.
- simple device assists is the communication of information from patient via dentist to technician.
- used to determine the vertical and horizontal position of anterior teeth relative to a point on the denture base (e.g. incisive papilla)
additional information which can be used to data transfer/position teeth
photos or casts of existing dentures
A-A
centre line
The central incisor teeth are set on either side of the centre line
B-B
occlusal plane (central incisal plane)
The centrals are set 1 mm below the line with the lateral and canine teeth set on the line
C-C
residual alveolar ridge contour
provides a guide to the length of the occlusal table
Teeth should not be set on an incline to assist occlusal balance and denture stability
D-D
canine line
