The Dental Articulator












39
e Dental
Articulator
3
What Is an Articulator?
A dental articulator is a mechanical device that simulates mandibular movements in relation to the
maxilla. The articulator should duplicate the patient’s occlusion accurately to allow proper diagnosis
and treatment planning as well as fabrication of indirect restorations that are in harmony with the
masticatory system and t well in the patient’s mouth with minimal chairside adjustments needed. The
rst step in transferring the patient’s occlusion to an articulator involves taking accurate impressions
to fabricate diagnostic casts; the articulator has upper and lower components where the maxillary
and mandibular casts should attach. Interocclusal records are taken to transfer occlusal relationships
to the articulator, and certain adjustments to articulator settings may be done depending on its type
(non-, semi-, or fully adjustable) to reproduce the patient’s occlusion. Occlusion is dynamic and
involves dierent factors and curvatures, so the procedures involved in transferring occlusion to an
articulator should be done adequately and precisely.
Uses of Articulators
Articulators may be used in diagnosis, treatment planning, and treatment as follows:
Diagnose the state of occlusion in both the natural and articial dentition and identify possible
discrepancies
Plan the dental procedures based on the relationship between opposing teeth
Use as a patient communication tool to show the treatment plan, allowing the patient to make an
informed decision and increasing treatment acceptance
Aid in the fabrication of precise restorations and prostheses by fabricating diagnostic wax-ups,
creating provisional restorations from the wax-ups, and minimizing chairside adjustments needed

The Dental Articulator
40
3
Interocclusal Records
4
Interocclusal records can be done using several materials and techniques. Precision in record making
as well as knowledge of the properties of the material used are essential in obtaining accurate records.
Maximal intercuspation record
Maximal intercuspation is recorded by asking patients to occlude their teeth together with a bite
registration material such as wax or silicone placed on the occlusal surfaces between the maxillary
and mandibular arches (Fig 3-1).
Fig 3-1 (a and b) Maximal intercuspation record.
a b
Centric relation record
19,20
The base layer of the centric relation bite record is made of hard wax that is softened and gently
pressed against the maxillary teeth to obtain slight maxillary teeth imprints. The wax is removed,
chilled, and reseated to check t and stability. Softer wax (Aluwax) is then added to the mandibular
side of the base layer, and the mandible is manipulated into centric relation to record impressions of
the mandibular teeth at three points (anterior, right, and left lateral segments). The mandible can be
manipulated by the chin point guidance technique or the bilateral manipulation technique.
Bilateral manipulation technique
Bimanual/bilateral manipulation technique was rst described by Dr Pete Dawson and involves seating
the condyles in the fossa by stretching the lateral pterygoid.
4
The patient should be in a supine position
with the head tilted to the back, and the dentist should be directly behind the patient. The dentist places
his or her hands on the mandible with the ngers distal enough to cradle the angle of ramus and provide
the correct orientation and direction of the force. The four ngers of each hand are placed along the
lower border of mandible resting against the bone (the fth nger behind the angle of the mandible) and
the thumbs should be placed on the chin and should be touching each other. The dentist should apply
rm pressure against the mandible, pressing downward with the thumbs and slightly upward with the
ngers, guiding the mandible into the soft wax until interocclusal contact occurs and mandibular teeth
imprints are obtained. The hand position for the bilateral manipulation technique is crucial and allows
the correct direction of force from the ngers to seat the condyles in the fossa (Fig 3-2a).

Interocclusal Records
41
Chin point guidance technique
To perform the chin point guidance technique, the patient is seated upright and the dentist is posi-
tioned in front of the patient. The dentist holds the patient’s chin by the thumb and index nger rmly,
and the patient’s mandible is guided by manual maneuvering a few times about the hinge axis until
the mandibular teeth just indent the registration material. The risk with this method is the ease with
which the condyles may be over-retruded (Fig 3-2b).
Fig 3-2a Bilateral manipulation technique. Fig 3-2b Chin point guid-
ance technique.
Fig 3-3  Protrusive record.
Protrusive record
The wax wafer is trimmed to the size of the centric relation record, then warmed and positioned against
the maxillary posterior teeth. The patient is then manipulated into centric relation, keeping the teeth
separated, then the patient slowly moves the mandible forward 4 to 6 mm (canines should be end to
end) and closes into the wax to create indents. This position is maintained while cooling the wax with
a stream of air until the wax is no longer soft, then the patient is instructed to snap open. The record
should have adequate cuspal indents and no perforations (Fig 3-3).
Lateral records
The wax wafer is trimmed to the size of the centric relation record then warmed and positioned against
the maxillary posterior teeth. The patient is guided into centric relation, keeping the teeth separated, then
asked to move the mandible 4 to 6 mm laterally and close into the wax to create indents (canines should
be approximately end to end). This procedure is done for both the right and left sides (Fig 3-4).

The Dental Articulator
42
3
Articulator Parameters
The following parameters are considered when using articulators.
Transverse horizontal axis
4,10
The transverse horizontal axis is an imaginary line
passing through the mandibular condyles when
they are in their most unstrained retruded position
in the glenoid fossa. When the mandible moves
up and down, cusp tips of mandibular teeth move
along an arc in the sagittal plane with the center
of rotation at the transverse horizontal axis. The
distance between the axis of rotation relative to
the cusp tips should be reproduced on the artic-
ulator to avoid dierences in the radius of closure
between the patient’s mouth and the articulator,
which affect placement of cusps, ridges, and
grooves in an occlusal restoration (Fig 3-5).
The facebow
4,10
The mandibular hinging movement around the horizontal axis is repeatable. Facebows are used
to record the anteroposterior and mediolateral spatial position of the maxillary occlusal surfaces
in relation to this transverse horizontal axis, that is, the relationship between the maxilla and the
temporomandibular joint. The facebow is transferred from the patient and attached to the articulator
to transfer the recorded relationship so that the maxillary cast is mounted in the correct position
relative to the hinge axis of the articulator, and then the mandibular cast is related to the maxillary
cast using a centric relation interocclusal record. There are two types of facebows available: kinematic
and arbitrary hinge axis facebow.
Kinematic facebows record the exact terminal hinge axis, which is essential in transferring information
from the patient to a fully adjustable articulator, resulting in a highly accurate mounting of the casts
on the articulator; both kinematic facebows and fully adjustable articulators are considered complex
Fig 3-4a  Right lateral record. Fig 3-4b Left lateral record.
Fig 3-5 Transverse horizontal axis. The distance be-
tween cusp tips and axis of rotation on the articulator
should simulate that of the patient’s.
Circular arc
of rotation
Transverse horizontal
axis

Articulator Parameters
43
devices and dicult to master. The kinematic facebow consists of horizontal arms extending to the
region of the ears and xed to the mandibular teeth; the arms have a pin with a grid underneath. As the
mandible opens and closes, if the pin is not in the terminal hinge axis position, it will trace an arc in a
forward, backward, upward, or downward direction that indicates the adjustment needed. The terminal
hinge axis position is reached when the pin remains stationary and no longer creates an arc (Fig 3-6).
Arbitrary hinge axis facebows approximate the position of the terminal hinge axis, typically to
the position external to the auditory meatus, and they are considered less accurate. However, they
are more convenient and suitable for most routine restorative dental procedures and are used in
conjunction with semiadjustable articulators (Fig 3-7).
Fig 3-6 Kinematic facebow.
Fig 3-7 Whip Mix arbitrary hinge axis facebow.
Condylar guidance
21,22
Condylar guidance is also referred to
as condylar path angle (CPA), condylar
inclination, angle of eminence, or poste-
rior controlling factor of mandibular move-
ment. This refers to the steepness of the
articular eminence, or in other words the
angle at which the mandibular condyle
descends along the articular eminence in
the sagittal plane. This angle is important
because it aects the cusp height. It varies from person to person and from one side to the other. The
goal of registering the condylar guidance is to program the articulator for simulating the patient’s condy-
lar movements as accurately as possible (Fig 3-8). In protrusion, the mandible moves downward and
forward as the condyle descends along the articular eminence. The steeper the eminence, the more the
condyle moves inferiorly and the more the mandible and mandibular teeth move downward. The atter
the eminence, the less the condyle moves inferiorly and the less the mandible and mandibular teeth move
downward.
4
Therefore, to avoid eccentric contacts in protrusion, the angle of the cusps should be less than
Fig 3-8 (a) Human temporomandibular joint. (b) Condylar
guidance.
a b

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39e Dental Articulator3What Is an Articulator?A dental articulator is a mechanical device that simulates mandibular movements in relation to the maxilla. The articulator should duplicate the patient’s occlusion accurately to allow proper diagnosis and treatment planning as well as fabrication of indirect restorations that are in harmony with the masticatory system and t well in the patient’s mouth with minimal chairside adjustments needed. The rst step in transferring the patient’s occlusion to an articulator involves taking accurate impressions to fabricate diagnostic casts; the articulator has upper and lower components where the maxillary and mandibular casts should attach. Interocclusal records are taken to transfer occlusal relationships to the articulator, and certain adjustments to articulator settings may be done depending on its type (non-, semi-, or fully adjustable) to reproduce the patient’s occlusion. Occlusion is dynamic and involves dierent factors and curvatures, so the procedures involved in transferring occlusion to an articulator should be done adequately and precisely.Uses of ArticulatorsArticulators may be used in diagnosis, treatment planning, and treatment as follows:• Diagnose the state of occlusion in both the natural and articial dentition and identify possible discrepancies• Plan the dental procedures based on the relationship between opposing teeth• Use as a patient communication tool to show the treatment plan, allowing the patient to make an informed decision and increasing treatment acceptance• Aid in the fabrication of precise restorations and prostheses by fabricating diagnostic wax-ups, creating provisional restorations from the wax-ups, and minimizing chairside adjustments needed The Dental Articulator403Interocclusal Records 4Interocclusal records can be done using several materials and techniques. Precision in record making as well as knowledge of the properties of the material used are essential in obtaining accurate records. Maximal intercuspation record Maximal intercuspation is recorded by asking patients to occlude their teeth together with a bite registration material such as wax or silicone placed on the occlusal surfaces between the maxillary and mandibular arches (Fig 3-1).Fig 3-1 (a and b) Maximal intercuspation record.a bCentric relation record19,20The base layer of the centric relation bite record is made of hard wax that is softened and gently pressed against the maxillary teeth to obtain slight maxillary teeth imprints. The wax is removed, chilled, and reseated to check t and stability. Softer wax (Aluwax) is then added to the mandibular side of the base layer, and the mandible is manipulated into centric relation to record impressions of the mandibular teeth at three points (anterior, right, and left lateral segments). The mandible can be manipulated by the chin point guidance technique or the bilateral manipulation technique.Bilateral manipulation techniqueBimanual/bilateral manipulation technique was rst described by Dr Pete Dawson and involves seating the condyles in the fossa by stretching the lateral pterygoid.4 The patient should be in a supine position with the head tilted to the back, and the dentist should be directly behind the patient. The dentist places his or her hands on the mandible with the ngers distal enough to cradle the angle of ramus and provide the correct orientation and direction of the force. The four ngers of each hand are placed along the lower border of mandible resting against the bone (the fth nger behind the angle of the mandible) and the thumbs should be placed on the chin and should be touching each other. The dentist should apply rm pressure against the mandible, pressing downward with the thumbs and slightly upward with the ngers, guiding the mandible into the soft wax until interocclusal contact occurs and mandibular teeth imprints are obtained. The hand position for the bilateral manipulation technique is crucial and allows the correct direction of force from the ngers to seat the condyles in the fossa (Fig 3-2a). Interocclusal Records41Chin point guidance technique To perform the chin point guidance technique, the patient is seated upright and the dentist is posi-tioned in front of the patient. The dentist holds the patient’s chin by the thumb and index nger rmly, and the patient’s mandible is guided by manual maneuvering a few times about the hinge axis until the mandibular teeth just indent the registration material. The risk with this method is the ease with which the condyles may be over-retruded (Fig 3-2b).Fig 3-2a Bilateral manipulation technique. Fig 3-2b Chin point guid-ance technique.Fig 3-3  Protrusive record.Protrusive recordThe wax wafer is trimmed to the size of the centric relation record, then warmed and positioned against the maxillary posterior teeth. The patient is then manipulated into centric relation, keeping the teeth separated, then the patient slowly moves the mandible forward 4 to 6 mm (canines should be end to end) and closes into the wax to create indents. This position is maintained while cooling the wax with a stream of air until the wax is no longer soft, then the patient is instructed to snap open. The record should have adequate cuspal indents and no perforations (Fig 3-3). Lateral records The wax wafer is trimmed to the size of the centric relation record then warmed and positioned against the maxillary posterior teeth. The patient is guided into centric relation, keeping the teeth separated, then asked to move the mandible 4 to 6 mm laterally and close into the wax to create indents (canines should be approximately end to end). This procedure is done for both the right and left sides (Fig 3-4). The Dental Articulator423Articulator ParametersThe following parameters are considered when using articulators.Transverse horizontal axis4,10The transverse horizontal axis is an imaginary line passing through the mandibular condyles when they are in their most unstrained retruded position in the glenoid fossa. When the mandible moves up and down, cusp tips of mandibular teeth move along an arc in the sagittal plane with the center of rotation at the transverse horizontal axis. The distance between the axis of rotation relative to the cusp tips should be reproduced on the artic-ulator to avoid dierences in the radius of closure between the patient’s mouth and the articulator, which affect placement of cusps, ridges, and grooves in an occlusal restoration (Fig 3-5).The facebow4,10The mandibular hinging movement around the horizontal axis is repeatable. Facebows are used to record the anteroposterior and mediolateral spatial position of the maxillary occlusal surfaces in relation to this transverse horizontal axis, that is, the relationship between the maxilla and the temporomandibular joint. The facebow is transferred from the patient and attached to the articulator to transfer the recorded relationship so that the maxillary cast is mounted in the correct position relative to the hinge axis of the articulator, and then the mandibular cast is related to the maxillary cast using a centric relation interocclusal record. There are two types of facebows available: kinematic and arbitrary hinge axis facebow.Kinematic facebows record the exact terminal hinge axis, which is essential in transferring information from the patient to a fully adjustable articulator, resulting in a highly accurate mounting of the casts on the articulator; both kinematic facebows and fully adjustable articulators are considered complex Fig 3-4a  Right lateral record. Fig 3-4b Left lateral record.Fig 3-5 Transverse horizontal axis. The distance be-tween cusp tips and axis of rotation on the articulator should simulate that of the patient’s.Circular arc of rotationTransverse horizontal axis Articulator Parameters43devices and dicult to master. The kinematic facebow consists of horizontal arms extending to the region of the ears and xed to the mandibular teeth; the arms have a pin with a grid underneath. As the mandible opens and closes, if the pin is not in the terminal hinge axis position, it will trace an arc in a forward, backward, upward, or downward direction that indicates the adjustment needed. The terminal hinge axis position is reached when the pin remains stationary and no longer creates an arc (Fig 3-6). Arbitrary hinge axis facebows approximate the position of the terminal hinge axis, typically to the position external to the auditory meatus, and they are considered less accurate. However, they are more convenient and suitable for most routine restorative dental procedures and are used in conjunction with semiadjustable articulators (Fig 3-7). Fig 3-6 Kinematic facebow.Fig 3-7 Whip Mix arbitrary hinge axis facebow.Condylar guidance21,22Condylar guidance is also referred to as condylar path angle (CPA), condylar inclination, angle of eminence, or poste-rior controlling factor of mandibular move-ment. This refers to the steepness of the articular eminence, or in other words the angle at which the mandibular condyle descends along the articular eminence in the sagittal plane. This angle is important because it aects the cusp height. It varies from person to person and from one side to the other. The goal of registering the condylar guidance is to program the articulator for simulating the patient’s condy-lar movements as accurately as possible (Fig 3-8). In protrusion, the mandible moves downward and forward as the condyle descends along the articular eminence. The steeper the eminence, the more the condyle moves inferiorly and the more the mandible and mandibular teeth move downward. The atter the eminence, the less the condyle moves inferiorly and the less the mandible and mandibular teeth move downward.4 Therefore, to avoid eccentric contacts in protrusion, the angle of the cusps should be less than Fig 3-8 (a) Human temporomandibular joint. (b) Condylar guidance.a b The Dental Articulator443the angle of eminence or condylar inclination (Fig 3-9). Condylar guidance on the articulators should be an approximate duplication of the condylar path in patients to fabricate accurate restorations. The following methods are used to determine the condylar inclination in clinical practice:• The method based on the disocclusion upon protrusion, which employs intraoral wax records and calculating the angle while programming on the articulator (ie, obtaining individual protrusive or lateral interocclusal records). This is considered the most feasi-ble and least complicated method. To utilize this method, the condylar guidance should be set to zero, the progressive side shifts should be set to their most open position, and the incisal pin should be loosened and raised to prevent interferences. The record is then placed on the inverted upper frame of the articulator, and the mandibular cast is gently seated into the protrusive record. As a result, the condyles will move away from the posterior and superior walls (Fig 3-10a). Using sight and touch, the condylar guide is rotated (one side at a time) until the condyle touches the superior wall of the condylar guidance, and then the clamp knob is tightened (Figs 3-10b and 3-10c). The lateral records can also be used to calculate the condylar guidance.a bcFig 3-10 (a to c) Setting the condylar guidance on Whip Mix semiadjustable articulator using protrusive records.Fig 3-9 Condylar guidance and anterior guidance are the same, causing the mandible to move from the ref-erence plane at a 45-degree angle. For the mandibular premolar to be disoccluded from the maxillary premolar during protrusion, the cuspal inclines must be less than 45 degrees. (Redrawn from Okeson.4) Articulator Parameters45• A graphic method in which the condylar path is recorded on a tracing card with a pencil lead attached to the stylus of a facebow. The patient is asked to protrude, and the angle of the path is obtained by measuring the angle formed by the tangent drawn to the functional portion of the tracing.• Radiographic methods involving the use of panoramic and lateral cephalometric radio-graphs whereby the condylar path angle is measured on the radiograph relative to the Frankfort horizontal plane, which is a reference plane passing through the right and left porion and the left orbitale (Fig 3-11). • Average value settings used with mean inclina-tions of normal adult eminence morphology. Reported values vary from 21 to 64 degrees. Setting the condylar inclination at a atter than average value ensures disocclusion of the poste-rior teeth during excursions. However, if the indi-vidual inclination of the eminence is very steep or very at, guidance obtained from average value settings may interfere with achieving balanced occlusion or posterior disocclusion.Fig 3-11 (a and b) Radiographic determination of the condylar path angle; blue line is the condylar inclination, yellow line is Frankfort horizontal plane.a bAnterior guidanceAnterior guidance or anterior controlling factor of mandibular movement refers to the ability of anterior teeth to guide the posterior teeth apart during protrusive mandibular movement. This disocclusion is important as posterior teeth can only tolerate horizontal forces well and do not tolerate oblique or laterally directed forces; therefore, adequate anterior guidance is necessary to protect posterior teeth. Anterior guidance is determined by the amount of vertical and horizontal overlaps of anterior teeth, which depends on their position, length, and angulation. Contact between anterior teeth in protrusion disoccludes posterior teeth; therefore, changes in the amount of anterior teeth overlap can aect cusp height as follows: (1) An increased vertical overlap leads to more movement of the mandible downward to disocclude posterior teeth and therefore allows for increased cusp height. (2) An increased horizontal overlap results in decreased movement of the mandible downward to disocclude posterior teeth, and therefore it is associated with decreased cusp height (Fig 3-12). Thus, the anterior guidance assumes the responsibility along with the condylar guidance in separating the posterior teeth in mandibular excursions, and both guidances determine the cusp height. The verti-cal and horizontal overlap of anterior teeth are transferred to the articulator by fabricating accurate diagnostic casts and taking accurate interocclusal records to mount the casts, and whenever anterior teeth are restored or waxed on the articulator, care should be taken to maintain an adequate anterior guidance to avoid damaging forces on posterior teeth in protrusion.4 The Dental Articulator463Intercondylar distanceIntercondylar distance is the distance between the two condyles of the mandible. This distance is import-ant because the pathway that the cusp follows in passing over the opposing tooth in lateral movement depends on the distance between the cusp and the condyle, which essentially depends on the inter-condylar distance. When the intercondylar distance increases, the distance between the condyle and the tooth increases, which increases the width of the angle between the mediotrusive and laterotrusive pathways of the posterior centric cusps.4 The intercondylar distance is only individually adjustable on fully adjustable articulators. Anatomical studies done by Bonwill have shown that the average intercondylar distance is 110 mm; therefore, most semiadjustable articulators have their intercondylar distance set at or close to this value. Because of the geometry involved in mandibular movement, this parameter has a relatively small impact on the accuracy of the nal restoration21 (Fig 3-13).Fig 3-13 The greater the intercondylar distance, the greater the distance between the condyle and the tooth and the wider the angle between the mediotrusive (A) and laterotrusive (B) pathway. (Redrawn from Okeson.4)Fig 3-12 (a) When the vertical overlap (VO) increases, the anterior guidance angle increases. (b) When the hori-zontal overlap (HO) increases, the anterior guidance angle decreases. (Redrawn from Okeson.4)Bennett angle23,24Mandibular lateral translation movement or Bennett movement was reported in 1908 by Dr Norman G. Bennett, who noticed a lateral shift in the position of the working/rotating condyle toward the side to which the movement was being made. The movement of the working condyle is therefore rotation Mandibular teeth Maxillary teetha b Articulator Parameters47around a vertical axis and a slight shift in a lateroposterior direction along the inclines of the glenoid fossa, making the Bennett movement. This sideways shift is generally no greater than 2 mm. Bennett movement is measured between the resting position and the displacement after a completed lateral movement of the mandible (Fig 3-14). Bennett angle is the angle formed between the average path of the nonworking condyle (orbiting condyle/translating condyle) and the sagittal plane as viewed from the horizontal plane during lateral mandibular movement. In other words, it is the angle between the movement paths of the nonworking condyle during protrusive and lateral movement of the mandible (Fig 3-15); the nonworking condyle generally moves downward, forward, and inward in lateral mandib-ular movements. The size of the Bennett movement can be measured directly or expressed indirectly based on the Bennett angle, and Bennett path angulation may range from 0 degrees to 35 degrees.Fig 3-14 Bennett movement.Fig 3-15 Sagittal plane/condylar path in protrusion from a horizontal view.There is a close relationship between the pattern of Bennett movement and the anatomy of the teeth as follows: During the lateral movement, cusps of posterior teeth should not interfere with the antagonist ones but should rather move through some well-identied ways of escape. The greater the lateral translation movement of the mandible, the shorter the posterior cusps should be in order to avoid interfering contacts, and the less the lateral translation movement of the mandible, the longer the posterior cusps can be without causing interference. Therefore, it is important to record the path of the Bennett movement and arrange the cusps of the teeth so that they can pass each other without interferences during function.4Timing of the Bennett movement in lateral excursion plays an important role too; Bennett move-ment can follow a uniform course (progressive side shift), or it may be more pronounced at the start of the mandibular movement (immediate side shift) (Fig 3-16). Progressive side shift (ie, integrated or distributed Bennett movement) means that the working condyle is displaced out of the resting position to the side steadily during lateral movement of the mandible; the lateral translation movement occurs with the eccentric movement. Immediate side shift means that the condyle is displaced to the side at the start of lateral movement of the mandible. When immediate side shift is present, the amount and direction of the lateral movement will markedly inuence the occlusal morphology versus when the shift occurs later; the amount and direction of the lateral translation will have less eect on the Nonworking sideAmount of lateral movementWorking sideWorking sideBennett movement The Dental Articulator483occlusal morphology; generally the more immediate the side shift, the shorter the posterior teeth. Because the Bennett movement and the Bennett angle aect cusp height and occlusal morphology, this information should be transferred to the articulator for accurate reproduction of occlusal anat-omy. Most semiadjustable articulators allow for a Bennett movement of the working condyle only in a straight line from the centric position in which the casts are mounted to the maximum laterotrusive position. The Bennet angle adjustment on the articulator is thus transferred through accurate right and left laterotrusive records that are carefully seated on the upper cast of the articulator (with the upper frame inverted), then the lower cast is gently seated into the lateral record, the side shift locking screw is loosened, the side shift guide is moved until it touches the side of the condyle, and then the screw is retightened (Fig 3-17). Fully adjustable articulators and a few semiadjustable articulators also provide adjustment of immediate and progressive Bennett movements, which is needed in cases of signicant immediate lateral translation movement.Fig 3-16 Immediate side shift and progressive side shift.Fig 3-17 Using lateral records to set the Bennett angle on a Whip Mix semiadjustable articulator.Types of Articulators 4,9,19Nonadjustable articulatorsA nonadjustable articulator may be referred to as an occluder (Fig 3-18a). It allows opening and closing movements around a xed axis, and maximal intercuspal position is repeatable and accu-rate, but excursive movements cannot be reproduced as it does not provide a representation of the natural relationship of the temporomandibular joint. The distance between the hinge and the teeth is signicantly less on nonadjustable articulators, leading to a steeper circular arc of rotation, and therefore premature contacts may occur (Figs 3-18b and 3-18c). Using these articulators results in increased chairside time to adjust restorations intraorally to the appropriate eccentric movements; therefore, their use should be limited to simple cases such as single restorations. The only record needed for mounting casts on nonadjustable articulators is the maximal intercuspation record (see Fig 3-1). Side-shift guideCondyleImmediate side shiftProgressive side shiftSide-shift locking screw Types of Articulators49Fully adjustable articulatorsFully adjustable articulators are the most accu-rate devices to simulate mandibular move-ments. However, their usefulness is limited due to the complexity of record making and artic-ulator adjustment. These articulators are very sophisticated, have a wide range of positions, and are able to reproduce all mandibular border movements. Thus they allow the achievement of prostheses that are more compatible with the actual status of the patient with minimal chair-side time adjustments. The exact terminal hinge axis position can be transferred to fully adjust-able articulators by using a kinematic facebow (see Fig 3-6), the condylar path angle can be duplicated with the specic curvature of the patient rather than a straight pathway as in semiadjustable articulators, and the exact Bennett angle and immediate lateral side shift can both be adjusted, allowing for more accurate reproduction of occlusal anatomy without interferences. The intercondylar distance is set at the precise millimeter distance as determined from the patient. Fully adjustable articulators are not very popular due to their complex mounting and high cost (Fig 3-19). Fig 3-18a Nonadjustable articulator.Fig 3-18b The distance between the hinge and the teeth is signicantly less on nonadjustable versus se-miadjustable articulators, leading to a steeper arc (ar-row B), and therefore premature contacts may occur.Fig 3-18cFig 3-19 Whip Mix fully adjustable articu-lator.25 The Dental Articulator503Semiadjustable articulatorsSemiadjustable articulators are able to partially reproduce the determinants of occlusal morphology. They have limitations compared to the fully adjustable articulators, but it is possible to compensate for these limitations, resulting in nal restorations that are compatible with those fabricated using a fully adjustable articulator. The semiadjustable articulator accepts an arbitrary hinge axis facebow, which estimates the position of the hinge axis approximate to the external auditory meatus (see Fig 3-7). The condylar inclination can be adjusted to conform to that of the patient, but only in a straight pathway; Bennett angle also can be adjusted, but only in a straight line from the centric position in which the casts are mounted to the maximum laterotrusive position. Intercondylar distance is set at or close to 110 mm rather than an exact measurement as with fully adjustable articulators. Anterior guidance is determined by reference to the overbite and overjet of anterior teeth, or if the overbite and overjet of anterior teeth are lost, an average value can be set. Semiadjustable articulators are either arcon or nonarcon articulators.Arcon versus nonarcon articulator Arcon articulators (Fig 3-20) have the condylar elements on the lower member of the articulator, just as the condyles are located on the mandible, and the mechanical fossae are placed on the upper member of the articulator, simulating the position of the glenoid fossa in the skull. In nonarcon artic-ulators this is reversed: the glenoid fossa is at the lower member, and the condylar elements are at the upper member (Fig 3-21).Fig 3-20 Whip Mix semiadjustable arcon articulator.26 Arrow pointing to condyle.Fig 3-21 Semiadjustable nonarcon ar-ticulator (Balance Hager & Werken).27 Arrow pointing to condyle.Articulator partsDespite all the special structural features of the dierent devices, the basic components of any articulator are the same (Fig 3-22). Each device has a body that is the central portion to which an upper member and a lower member are attached. Each member has removable mounting plates. The upper part of the Steps for Mounting Casts51Fig 3-23a Incisal guide pin is set at zero mark.Fig 3-23b Condy-lar guidance is set at 30 degrees.Fig 3-23c Bennett angle is set at 15 degrees.Fig 3-22 Articulator parts.Condylar housingCondylar ballsLower memberMounting platesIncisal tableIncisal pinUpper memberdevice is connected to the lower part by means of a simulated joint, which is arranged as a condylar housing where the two condylar balls sit to simu-late protrusive and lateral movements. The incisal table is located at the anterior portion of the lower member and provides support to the incisal pin.Steps for Mounting CastsWhip Mix semiadjustable articulators are very popular and widely used by most dental schools. The casts used in this book for practicing waxing in occlusion and esthetic wax-ups are a duplicate of the typodont model D85SDP-200 (Kilgore International), on which teeth nos. 13, 14, 29, and 30 have their occlusal thirds cut o and the maxil-lary anterior teeth have been prepared for porce-lain veneers; the casts can be poured from Viade molds no. 3814. After the molds have been poured, the casts are mounted on the articulator and then waxed to restore all the missing surfaces while maintaining a functional occlusion by following the steps in the upcoming chapters. Because the casts do not belong to a patient, a facebow and interocclusal records are not obtained, the quick mount-remount jig is used to mount the upper cast, and then the lower cast is mounted in maxi-mal intercuspation. The condylar guidance is set to an average value of 30 degrees, and the Bennett angle is set to an average value of 15 degrees. Following are the steps for mounting casts: 1. Adjust the articulator settings.• Place the incisal guide pin in the incisal guide boss with the chisel end up and the round end down; set the incisal guide pin to the zero mark. At zero, the upper and lower members are parallel (Fig 3-23a).• Set the condylar guidance to 30 degrees (Fig 3-23b) and the Bennett angle to 15 degrees (Fig 3-23c). The Dental Articulator5232. Fabricate the remount index.• Fabricate the remount index from polyvinyl siloxane (PVS) putty impression material by mixing the material according to the manu-facturer’s instructions and adapting it to the occlusal surfaces of the upper cast on one side and the quick mount-remount jig on the other side (Fig 3-24).• Attach the quick mount-remount jig to the lower member of the articulator and seat the remount index in it.• Attach the mounting plate to the upper member of the articulator and check for clearance between the cast and the mounting plate.3. Mix the mounting stone.Fig 3-24 The remount index is fabricated by adapt-ing PVS putty impression material between the upper cast and the quick mount-remount jig, then the upper mounting plate is attached to the upper member of the articulator to ensure clearance for the mounting stone.Fig 3-25a Creating retention grooves in the base of the upper cast.Fig 3-25b Soak the base of the cast in water.• Before mixing the mounting stone, place retention grooves or lugs in the upper cast and soak its base in water to prepare it for mounting (Figs 3-25a and 3-25b). Steps for Mounting Casts53Fig 3-26a Place some mounting stone on the cast and some on the mounting plate.Fig 3-26b Closing the articulator with the mounting stone to mount the upper cast.4. Mount the upper cast.• Put some stone on the mounting plate and some on the cast, then close the articulator (Fig 3-26a).• Hold the upper cast steady on the remount index with the quick mount-remount jig in place until stone sets (Fig 3-26b).Fig 3-25c Mixing the mounting stone.• Start by wetting the rubber bowl with water (Fig 3-25c).• Add the recommended amount of water per manufacturer instructions (26 mL for Whip Mix mounting stone) into the rubber bowl.• Shake the stone to one end of the packet before opening carefully, then add powder to the water quickly without splashing.• Mix thoroughly and quickly without ip-ping powder everywhere. The nal consis-tency has form but is not sti. The Dental Articulator543Fig 3-27a Invert the articulator and place the lower cast in the maxi-mal intercuspal position with the upper cast.Fig 3-27b Mounting the lower cast in the maximal intercuspal position.5. Mount the lower cast.• Prepare retention grooves or add lugs to the lower cast and soak its base in water.• Invert the articulator and hand articulate the lower cast with the upper cast in the maximal intercuspal position (Fig 3-27a).• Attach the mounting plate to the lower member of the articulator and check for clearance between the mounting plate and the cast.• Mix the mounting stone and add some to the mounting plate and some to the cast.• Close the lower member of the articulator and allow the mounting stone to set (Fig 3-27b).• To dress the cast, grasp the mounted cast securely, touching both the cast and the mounting plate, then mix a new batch of mounting stone and apply the mounting stone between the mounting plate and the cast neatly (Fig 3-26c). • Remove any excess stone on the base of the mounting plate (Fig 3-26d).Fig 3-26c Dressing the cast. Fig 3-26d Final dressed upper cast. Steps for Mounting Casts55• After setting of the stone, ensure that the casts are properly mounted in maximal intercuspa-tion (the second molars should hold shimstock on both sides) and that the incisal pin is set at zero with the teeth in maximal intercuspation. Dress the lower cast in the same manner as the upper cast (Figs 3-27c and 3-27d).Fig 3-27c Final mounted casts.Fig 3-27d Mounted casts should hold shimstock at the second molars of both sides.

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