Articulators

Articulators
lek. dent. Krzysztof Gawriołek
Oral Rehabilitation Clinic
An Articulator is a mechanical device used in dentistry to which casts of the maxillary
(upper) and mandibular (lower) teeth are fixed and reproduces recorded positions of the
mandible in relation to the maxilla. An articulator assists in the fabrication of removable
prosthodontic appliances (dentures), fixed prosthodontic restorations (crowns, bridges,
inlays and onlays)and orthodontic appliances.
A mechanical representation of the jaws and temporo-mandibular joints
An articulator may be defined as a mechanical device that represent the
temporomandibular joint and jaw members to which maxillary and mandibular casts may
be attached to simulate jaw movement.
What can we obtain?
• With an articulator we can transfer the
relationship between the occlusal surface to the
hinge axis to the articulator (tech. lab.)
• In this way, like in the natural state, occlusal
surfaces of restorations will be reffered condyles
position, both in the static and dynamic situation.
Relationship between maxilla and mandibule
Wax bite
Silicone bite
Toothed arches
Facial bow
and
articulator
Wax rims
Toothless arches
Facial bow
and
articulator
Relationship between occlusal plane and hinge axis
USES
1.
To diagnose the state of occlusion in both the natural and
artificial dentition.
2.
To plan the dental procedures based on the relationship
between opposing natural and artificial teeth (Ex.
Evaluation of the possibility of balance occlusion).
3.
To aid in the fabrication of restorations and prosthodontics
replacements.
4.
To correct and modified complete restorations.
5.
To arrange artificial teeth.
Divisions
• Arcon
• Non-arcon
• Standard
• Semi-adjustable (semi-individual)
• Fully adjustable (individual)
Arcon type articulator:
An articulator where the condylar housings are part of the upper member
and the condyles are located on either side of the lower member. This
configuration looks more like human anatomy, and is sometimes preferred
when using the instrument to describe and explain treatment to patients.
Non-Arcon type articulator:
An articulator with the equivalent condylar guides attached
to the lower member and the hinge axis to the upper
member. In a non-arcon articulator, unlike human anatomy,
the components representing condylar housings are found
in the lower member of the articulator, and the spheres
representing condyles are attached to either end of an axle
that is part of the upper member.
Types of articulators:
- Standard articulators
All condylar parameters are not adjustable (averange
values are stock set )
- semi-individual articulators
An articulator which is adjustable in one or more, but
not all of the following parameters:
saggital condylar path,
horizontal condylar path (Bennett movement),
Horizontal condylar path (ISS - Immediate Side Shift),
Side-shift (shift angle, Bennett angle)
protrusion,
retrusion,
distraction (shape of the glenoid fossae and eminintiae).
-Individual articulators
All condylar parameters can be set
Occludator (cast holder)
Types of articulators:
- Simple hinge
- Averange hinge
- Semi-adjustable
- Fully adjustable
Build of articulator
Facial bow
articulator
Upper member
Lower member
Upper member
Lower member
lock
mounting pad
lock
lever
mounting plate
Support pin
Incisal pin
Incisal guide
table
Nasal support
Facial bow
Joint piece
Biting fork
Refference
pointer
Ear pieces
PRACTICAL SIDE:
An analysis of occlusion
• When casts are mounted in articulators
an analyse of occlusion
should be performed
• Occlusion should be checked in static and
dynamic situation
Analysis of occlusion
Static
occlusion
• cental occlusion contacts
• Centric relation
Dynamic
occlusion
• guidances L & R
• working and non-working
side interferences
• protrusion
Analysis of static occlusion
-Contacts in central occlusion (triads and forces)
-Does central occlusion occurs in centric relation ?
-Does the patient have freedom in CO (is CO locked in)?
Analysis of dynamic occlusion
Excursive movements of mandible
- contacts during left and right laterotrusion
- anterior guidance: incisal g., canine g., group function g.
- interferences on working and non-working side during the
movement
Recording of occlusion
Two dimentional
marking the static and dynamic occlusal between teeth and then
describing those marks in writing, by diagram or photograph.
-Articulating paper
-Articulating foil
-T-Scan
Advantage : determine contacts between actual teeth
Disadvantage: inherent 2D record of a 3D entity
Recording of occlusion
Three dimentional
Analysis with study models
Advantage : permanent copy of patient’s occlusion, freedom of usage
Disadvantage: host of potential errors in production stage (ex. Not
accurate impressions, models not well casted or related each other,
choice of face bow, articulator, range of impressions, regitration and
casting materials)
Progressive articulating paper
occlusal contact
Surface around bite point
In this region appearance bite forse is
highest (in normal contact should have a
point appearance)
zone around the contact
pointpoint
contact point
intense contact
=
premature contact
poor contact
=
normal force
A tooth movement in alveolar on periodontal ligaments during ex.
mastication is 20 µm. A difference in 15 µm can be sensed by human
receptors in periodontium.
Conclusion: the final articulating foil must be thinner than 15-20 µm
ARTICULATING PAPERS
200 – 40 µm, 11 µm
Initial occlusal recording
Final oclusal recording (11 µm only)
ARTICULATING SILK
200
Initial occlusal recording
more break-resistant than paper
More pigment inside (up to 10 usage on model)
ARTICULATING FOIL
28 – 8 µm
initial and final occlusal recording
metal stripe with two-sides pigment
ARTICULATING INDICATORS AND SPRAYS
Indicator leaves a 3µm layer
Prosthetic restorations fitting control, recording contacts
on smooth surfaces of crowns etc.
T-SCAN
electronic measurement of occlusal contacts
The choice of articulator depends upon such factors as:
- Clinical purpose
- Availability of equipment
- Patient’s occlusion
- Skill of technician
- Expense
- Skill of the operator
The more closely the articulator matches the patients
anatomy (especially face type) , usually the better the
outcome and the less adjustment is required at dental
chair on fitting process.
CONCLUSION
An articulator is an important device that mechanical
analogues the temporomandibular joint & upper and
lower dental arches.
A device to which maxillary and mandibular casts can be
attached with the intend of simulating the functional &
parafunctional contact relationships of one arch to the
other.
Refferences:
-Wheeler's Dental Anatomy, Physiology And Occlusion (9th
Edition) By Stanley J. Nelson, DDS, MS
Management of Temporomandibular Disorders and Occlusion
(6th Edition)
by Jeffrey P. Okeson
-Functional Occlusion, From TMJ to Smile Design
by Peter E. Dawson
-Oral Rehabilitation: Clinical Determination of Occlusion
by Sumiya Hobo and Hisao Takayama