articulators in complete dentures by #asiandentalacademy

ARTICULATORS

Asian Dental Academy

www.asiandentalacademy.orgAbove KFC Restaurant main Road Hyderabad

http://www.asiandentalacademy.org/

INTRODUCTION In the fabrication of indirect dental prosthesis a mechanical device is used to relate opposing casts called an articulator

DEFINITIONAn articulator is mechanical device which represents TMJ and jaw members to which maxillary and mandibular casts may be attached

Primary function of articulator is to simulate patient in the absence of patient.

An articulator can simulate but they can not duplicate all mandibular movement


History of ArticulatorsTHE PLASTER ARTICULATOR1st described by Philip Pfaff in 1756A plaster extension on distal portion of mandibular cast

was grooved to serve as guide for a plaster extension on the maxillary cast this constitutes an articulator called slab articulator

BARN DOOR HINGE AXISADAPTABLE BARN DOOR HINGE KERR ARTICULATOR 1902NEW CENTURY AND MODIFIED NEW CENTURY

ARTICULATORS GORGE B SNOW 1906THE ACME ARTICULATOR Asian Dental Academy

HANAU HANAU MODEL H 110 ARTICULATOR IN 1926 EVOLVED FROM HANAU MODEL115 MANUFACTURED IN1922

MODEL110 MODIFIED IN 1927 WITH INCISAL GUIDANCE TABLE

THE HAGEMAN BALANCERPHILIPS STUDENT ARTICULATOR By PHILIPS IN 1926 STRANSBERY TRIPOD By STRANSBERY IN 1929HOUSE ARTICULATOR By M M HOUSE 1930PHILIPS OCCLUSOSCOPE By PHILIPS 1938STEPHEN ARTICULATOR (modified) 1940


STUART ARTICULATOR By CHARLES STUART IN 1955 -56HANAU MODEL H2 SERIES 1958PANKY MANN ARTICULATOR IN 1955 By LINDSAY PANKEY HANAU H2-O; HANAU H2-X; HANAU H2-PRDENTATUS ARL By DENTATUS IN 1958VERTICULATOR WILLIAM WINDISH IN 1960WHIPMIX ARTICULATOR By CHARLES STUART IN 1964SIMULATOR By EARNST R GRANGER IN 1968DENAR MODEL D4A By NILES GUICHET IN 1968DENTATUS ARO IN 1971PANADENT ARTICULATOR


Articulators: Minimal Requirements It should hold casts in the correct horizontal

and vertical relationship It should provide positive anterior vertical

stop It should accept a face bow record It should open and close in a hinge

movement The moving parts should move freely and be

machined accurately The non-moving parts should be a rigid

construction It should allow protrusive and lateral jaw

motion Asian Dental Academy

Additional desirable featuresAdjustable horizontal and lateral condylar guide

elementsThe condylar elements as a part of the lower frame

and the condylar guides a part of the upper frame

A mechanism to accept a third point of reference from a face bow transfer.

A terminal hinge position locking deviceRemovable mounting plates that can be repositioned

accuratelyAn adjustable incisal guidance tableAdjustable intercondylar width of the condylar elements


Articulator : uses.To open and close in a hinge mannerHold opposing casts in a predetermined mannerTo produce border and intraborder movements like in

the mouthTo diagnose dental occlusal conditions in natural and

artificial conditionsTo plan dental proceduresTo aid in the fabrication of the prosthesesTo correct and modify complete restorationsAs a teaching aid to study occlusion and mandibular

movements


Articulators: Advantages over mouth

On patients co-operationTo rely No need Allow operator to view patients occlusion from

the lingual side Refinement of patients occlusion can be easily be done on the

articulator than in the patients mouthSaves a lot of chair side timeMore procedures can be delegated to auxiliary personals when

using an articulatorThe patients saliva, tongue and cheek are not factors when using

an articulator.


Articulators : Classification

Based on theories of occlusion Based on type of inter occlusal recordsBased on ability to simulate jaw movements

(IPWS classification)

(Heartwell and rahn classification)Based on the adjustability of articulatorsAsian Dental Academy

Bonwill theory articulators

Designed by WGA BonwillThe teeth moves in relation to each

other as guided by condylar and incisal guidance

Also known as theory of equilateral triangle

Distance between the two condyles is equal to the distance between midpoint of the mandibular incisors and condyle


Theoretically the dimension of equilateral triangle is 4 inchesThese articulators allow lateral movements and permits the

movement of the mechanism only in horizontal plane


Conical theory articulatorLower teeth move over the surface of the upper teeth as over the

surface of the cone generating an angle of 45° with the central axis of the cone tipped 45° to the Proposed by RE Hall

occlusal plane.

Hall automatic articulator.Asian Dental Academy

Spherical theory articulatorLower teeth move over the surface of the upper teeth as over the

surface of the sphere with a diameter of 8“ with the center located at the glabella

The surface of the sphere moved over the glenoid fossa & articulating eminences.


Disadvantages of articulators based on the theory of occlusion

These are based on theoretical conceptsThere is no provision for variations from the theoretical relationships

that occur in different persons


Articulators based on the type of record used for their adjustment.

Inter occlusal record adjustment Made of base plate wax, zinc oxide eugenol, POP & acrylic resin

Graphic record adjustment.

Records of extreme border positions of mandibular movements.

Face bow pantograph can be attached

Hinge axis location for adjusting articulators


HEARTWELL AND RAHN CLASSIFICATION

Class I These are instruments that receive and reproduce stereogramThese articulators can be adjusted to permit individual

condylar movement in each of the three planes they are capable of reproducing the timing of the side shift of the orbiting (balancing) side and its direction on the rotating side

Hence these articulators are called as four dimensional instruments.

Eg: McCollum gnathoscope, Granger gnathoscope, Hanau kinoscope, Cosmax, Aderer simulator, Ney articulator, Stuart gnathoscopic computer, TMJ streographer, Denar D5A


CLASS IIThese instruments will not receive stereogram Some have fixed controls, others are adjustable but usually in no more

than two planes a close approximation of condylar movements patterns can be determined quickly and the information permits better adjustments to the condylar control or the selection of a guidance fossa that will closely match the condylar element movement gained from stereograms

Gnathology is defined as the science which deals with the masticatory apparatus as a whole including morphology anatomy histology physiology pathology and therapeutics

Referred as `gnathalogic’ instrumentso Stuart Articulator - Charles Stuart 1955o Denar D4A - Denar D5A o SimulatorHas four types Asian Dental Academy

TYPE I (HINGE)

Capable of opening and closing in hinge movement

Some permits limited non adjustable excursive like movements

eg: The barn door hinge, Trubite, Gariot, Twinstage occluder, Hageman balancer, Bonwill, Gysi simplex and adaptable, The centric relator Stephens models, Crescent models, Gysi, Acme

TYPE II (ARBITRARY)

Depends on specific theories of occlusion

eg: Monson, Handy II, The correlator, Transgraph, The gnathic relator, Verticulator


TYPE III (AVERAGE)

Designed to provide condylar element guidance by means of average positional records or mini recorder system

Horizontal or lateral guidance can be adjusted

Accepts face bow transfereg: House, Dentatus, Hanau, Whip mix ,Denar mark II and omni

TMJ, Panadent

TYPE IV ( SPECIAL)

Designed primarily for complete denture

eg : Stansberry tripod, Kile Dentograph, Irish Duplifunctional.


Based on the adjustability of the articulator. by Weinberg 1963Arbitrary articulators Can open and close only about a fixed horizontal axis Fixed condylar paths Incisal guide pin glide on an inclined plate on a fixed inclination

Semi adjustable articulators They have adjustable horizontal and lateral condylar and incisal paths, inter condylar distances. 2 types: Arcon and Non arcon

Fully adjustable articulators Capable of adjustment in all directional movements of mandible. Do not have condylar guidances; receptacles are present to be contoured into customized condylar and incisal guidances. Eg.Stuart instrument, Gnathoscope, SimulatorAsian Dental Academy

Based on plane of orientationThe Articulators which are based on the

Camper's line.

Kavo, Stratos,

The Articulators which are based on the

Frankfort horizontal plane.

Hanau, Dentatus, Whip-Mix,

Denar Mark II, Stuart


Based on the ability to simulate jaw movement

The INTERNATIONAL PROSTHODONTIC WORKSHOP on Complete Denture occlusion at the University of Michigan in 1972,

an articulator classification was developed.

This classification was based on articulator’s function, capability, intent and registration acceptance


Class I simple holding instrument capable of accepting a single Interocclusal record eg. Garriot’s Hinge, Barn hinge door.

Class II Instrument that permit horizontal as well as vertical motion but don’t accept face bow transfer

Type A- eccentric motion is based on average or arbitrary values

eg.Grittman’s articulator, Gysi’s Simplex Type B- Eccentric motion permitted is based on theories of arbitrary motions

eg. Maxillomandibular instrument

Type C- eccentric motion permitted is determined by patient’s engraving methods

eg. House’s articulatorAsian Dental Academy

Class III permit horizontal and vertical movements, do accept face bow transfer but facility is limited. Simulate condylar pathways using average or mechanical equivalent for the whole or part of condylar motion but cannot allow total customization

Type A - they accept a static protrusive record and they use equivalents for other types of motion

eg . Hanau articulators, Bergstrom articulator

Type B - accept static lateral protrusive record, use other equivalents for other types of motion

eg. Trubyte articulator, Hanau kinescope, Stansberry tripod, Neys articulator, Teledyne articulator, Whipmix articulator, Denar Mark II, Bergstrom’s arcon articulator.


Class IV accept three dimensional dynamic registration they allow point orientation of the cast using face bow transfer

type A-the condylar path is determined by engraving registrations produced by the patient this path can not be modified

eg. TMJ articulator by Kenneth Swanson

type B-similar to type A but they allow angulations and customization of the condylar path

eg. Stuart articulator, Denar D4A, Denar D5A, Simulator


Class ISimple holding instrument capable of accepting a single

interocclusal record vertical movements may or may not be possible

Slab articulatorA plaster extension on distal portion of mandibular cast was

grooved to serve as guide for a plaster extension on the maxillary cast this constitutes an articulator called slab articulator


Hinge-joint articulator; designed by J B Gariot consists of simple hinge with a set screw against a metal plate posteriorly serve as a vertical stop


Adaptable Barn- door hinge; has anterior vertical stop


Class II Instrument that permit horizontal as well as vertical motion but don’t accept face bow transfer

Type A- eccentric motion is based on average or arbitrary values

eg.GRITTMAN’S ARTICULATOR,Condyles are on the lower member and there paths are inclined 15 degree casts are mounted according to the Bonwill's triangle


eg.Gysi’s Simplex Condyles are on the lower member and there paths are inclined 30 degree Incisal guidance fixed at 60 degree


Average value articulator

30° 25°

5°


CLASS II TYPE BPermits eccentric motion based on arbitrary theories of

motion won’t accept face bow transfer

eg. Monson’s maxillomandibular instrument

Designed by Monson based on spherical theory of occlusionLower teeth move over the surface of the upper teeth as over

the surface of the sphere with a diameter of 8” with the center located at the glabella

The surface of the sphere moved over the glenoid fossae & articulating eminences.

Upper member of the articulator moves according to Monson’s spherical theory


CLASS II TYPE CPermits eccentric motion determined by patients engraving

methods eg. House’s articulatorA Needle House “chew in” record 4 metal studs in the upper rim against lower compound occlusal

rim. Diamond shaped pathways are generated the instrument.Also employs a rotatory grinder on the upper member for

milling in a 40/1000 inch elliptical areas so as to free the occlusion in centric occlusion

CLASS III Permit horizontal and vertical movements, do accept face bow transfer but facility is limited. Simulate condylar pathways using average or mechanical equivalent for the whole or part of condylar motion but cannot allow total customization

HANAU MATE ARTICULATORIt is an arcon instrument accept a

face bow transfer it has average condylar guidance of 30° Bennett angle 15° incisal guide table is 10° in both protrusive and lateral movement

They won’t accept a static protrusive record

Class III TYPE AType A -they accept a static protrusive record and they use

equivalents for other types of motion

eg. Dentatus, Hanau articulators,

DENTATUS • It is Designed in Sweden 1944

• Similar to Hanau but it is unique in that the relationship between upper and lower can be standardized with a gauge block so that cast can be transferred one to another articulator without changing the relationship


Hanau ArticulatorHanau H2• Designed by Rudolph Hanau• Condylar articulator• Fixed inter condylar distance of 110 mm• Accepts face bow transfer• Face bow can be aligned to the

Frankfort horizontal plane by infraorbital pointer • If incisal plane is used, it is adjusted at the upper notch on the

incisal pin which is 47 mm below the horizontal condylar plane

• Lateral horizontal inclinations are simulated by protrusive Interocclusal record and vertical condylar posts are rotated accordingly

• Incisal guide table adjusted in both sagittal and frontal planes

Incisal Guide TableA small rectangular strip of metal, It can be changed in antero-posterior direction and locked with

locknut under the platform. It should be flat and pin should be at the center.

A pair of lateral wings are present around the table.

Can be sloped towards the center of the table according to the lateral guidance required with help of elevating screws.

Any change in the vertical dimension will alter the position of incisal guide pin in relation to the incisal guide table for this IGT have to be readjusted to the vertical and horizontal overlap.

An incisal pin with an adjustable angled foot is available.This will keep the incisal pin in exact center of the table with

change in vertical dimension of 5 mm and it doesn’t require any adjustment of the incisal guide table.


Mounting procedure Mounting the maxillary cast Attach face bow to the articulator Maxillary cast is attached to the articulator using orientation jaw

relation record .Support the bite plane with a cast support to carry the additional

weight.. Maxillary cast is made flat and v-shaped notches are prepared on the

mounting surface at the periphery. This surface is lubricated with thin coating of petroleum jelly.

The cast is then securely seated in the denture base with the occlusal rim firmly resting in bite fork imprint.

Mixture of stone is placed on the cast, the upper member is swung back to embed the mounting plate and to bring the incisal pin into contact with the incisal guide.

s

Mounting the mandibular castMandibular cast is mounted after recording tentative and centric jaw relations.

Articulator with mounted maxillary cast is inverted to aid in mounting the Mandibular cast.

Maxillary occlusal rim is placed on the cast, mandibular occlusal rim is positioned over the maxillary occlusal rim without using the centric relation record and mandibular cast is placed in the lower rim measure and note the X dimension.

Now centric relation record is interposed and maxillary and mandibular occlusal rims with there casts are luted.

Adjust the pin so the X dimension us same.

Stone is placed on the cast and lower member is swung back to embed the mounting plate and incisal pin touching incisal guide.

Gently guide the maxillary cast to bring the anterior teeth into edge to edge contact.

Rotate the IGT antero-posteriorly to make contact with the end of the incisal pin and tighten the screw.

Maxillary cast is then guided for full right lateral relation to ensure the Bennett shift, lateral wing is elevated to contact the corner of the incisal pin and lock nut is tightened. The same will be done on other side.

Setting incisal guide table adjustment

Setting of horizontal condylar guidance

Incisal pin is raised out of contact.

Adjust lateral indication of the condylar posts at 15 degree.

Protrusive record is interposed between maxillary and mandibular occlusal rims the right and left condylar guidances are adjusted until accurate registration is evident.

Thumbnuts for horizontal inclination are then tightened to retain there protrusive adjustment.


Adjustment of lateral condylar guidanceCan be adjusted according to the Hanau’s equation for lateral

condylar guidance or with lateral relation record.

Hanau`s equation L=H/8+12

L=Lateral condylar guidance

H=Horizontal Condylar guidances


Mathematical Study of Hanau Articulators

Average anatomic location of hinge axis

For average anatomic location of hinge axis a Max error of 5 mm is considered .If the relation of the jaws to the hinge axis of the patient differ from relation of the casts to the hinge axis of the instrument, when a 3mm wax centric record is removed and articulator is closed an anteroposterior error of approximately 0.2mm would be produced .

Arbitrary location of anterior point of reference

An elevation of anterior part of the face bow decreases the protrusive condylar reading & vice versa.

Any of the commonly used arbitrary point of reference can change vertical height of the face bow mounting not more than + 16 mm .

When the face bow mounting is oriented 16mm high , there is reduction of 9°in condylar reading making it 31° from the lower member.


The effect of change in condylar inclination on occlusion

Working cusp inclines

The working condylar motion of Hanau is built into the machine & is dependent on the balancing condylar motion.

A difference of 10 degree in the working condylar inclination produces approximately a 1.3° change in the Bennett angle the net effect is practically immeasurable at the working condyle and half again as much at the 2nd molar working cusp inclines


BALANCING CUSP INCLINES

The hypothetical patient has a 40° cuspal inclines .

The 9° reduction in the protrusive reading due to elevation of the face bow decreases the second molar balancing cusp inclination to 35.5°, this error is of 0.2 mm for 3 mm cusp.


STRAIGHT CONDYLAR PATH The average Hanau articulator has a straight condylar slot

rather than a curved path.condylar path follows a curvature of ¾ inch radius. With

static records , only the centric relation & eccentric positions are recorded.


The midpoint of the excursion produces the maximum error with a straight condylar slot.

The maximum difference between a straight condylar path & one that is having ½ inch radius is 0.4 mm a maximum error of 0.4 mm produces 0.2 mm error at second molar. This is for a 3mm cusp height with a constant incisal guidance.

Working condylar movements

This The effective condylar movements in Hanau articulator is upward backward and lateral

movement contains lateral Bennett shift of 0°

The working cusp inclines at the 2nd molar would be average between the extreme guidance namely 15°, hence the articulator would produce working cusp inclines at the 2nd molar of 15° while the patient would require 30°

When restorations are placed a 15° difference produces an opening of 0.8mm at working cusp height


Hanau Arcon H2 Introduced by Hanau in 1977

IGT is same as H2 mechanical table in addition to this has ‘’ Pentacrylic” incisal guide table and pin provided for customization with acrylic resin

Upper and lower members are attached to each other by condyles and their guidances

Accepts face bow transfer primarily earpiece face bow

For kinematic face bow it condylar should be equipped with extendible shaft

Quite simIntrodilar to H2 except it is an Arcon instrument

Hanau radial shift Arcon instrument with fixed inter condylar distance

The condylar guidance of the articulator is designed to incorporate a curved immediate side shift with an adjustable progressive Bennett angle. the radial shift adjustment has a 3mm radius and allow up to 3mm of radial shift before intercepting the pre adjusted progressive Bennett angle

The condylar guidance is adjustable horizontally and curved superior wall with a 0.75” radius Asian Dental Academy

Hanau wide vue articulator


CLASS III TYPE BAccept face transfer Protrusive interocclusal records and some interocclusal record. Eg. Trubite articulator, Whipmix articulator TRUBITE ARTICULATORDesigned by Gysi in 1926It is an nonarcon instrument wih a fixed intercondylar distanceHorizontal condylar inclinations are individually adjustableIndividual bennette adjustments are near the center of intercondylar distance Incisal guide table is adjusted acoording to the gothic arch angle can accept lateral interocclusal records not allAsian Dental Academy

WHIPMIX ARTICULATORIt is semi adjustable Arcon type of articulatorIt is designed by Charles Stuart in 1955Its intercondylar distance is adjustable at three positions small(S)

96mm medium(M) 110mm, large(L) 124mm by means of removable condylar guidance spacers along the instruments horizontal axis

Accepts face bow transfer Horizontal condylar inclinations are set by means of lateral or

protrusive intercondylar record It is available with either mechanical guide table adjustable in both

frontal and sagittal planeOr with plastic incisal guide table that can be individually customized


Maxillary cast is transferred to the articulator with the help of face bow transfer.Mandibular cast is related to the maxillary cast by centric interocclusal record

Horizontal condylar inclination is determined either with the help of protrusive interocclusal record or lateral interocclusal record

Horizontal condylar inclination obtained with protrusive interocclusal record will slightly steeper than that obtained from lateral interocclusal record

Theoretically if protrusive interocclusal record is used to simulate lateral intercondylar inclination then occlusion developed in the laboratory may be heavy on the working side and light on the balancing side


Bennett angulation is set with lateral interocclusal record

the casts are seated in the LI record and medial wall of the condylar housing is adjusted until they contact the condyles

Incisal guide table

Provided with either with mechanical incisal guide table or plastic incisal guide table that can be individually customized with auto polymerizing resin the mechanical guide table has single sagittal table adjustment right and left frontal adjustment

Incisal guide pin is straight has a one flat end used with mechanical guide table and one rounded end used with plastic IGT


MODIFICATIONS OF WHIPMIX ARTICULATOR

Condylar thumb lock screw

For stabilization of condyles during hinge movement

Optional immediate side shift guides available from 0.25 mm to 1mm size is determined by amount of Bennett movement

Curved condylar guides horizontal or medial are designed to reflect average relationship between condyles and fossa


HANAU KINOSCOPEHas double condylar posts on each side inner condylar post have

the horizontal condylar guides and are adjusted mediolaterally to produce mechanical equivalent of intercondylar distance Bennett angle is adjusted by rotating centric cones against the horizontal axis shaft


CLASS IVAccept three dimensional dynamic registration and allow

point orientation of the cast using face bow transfer

Type A-The condylar path is determined by engraving registrations produced by the patient, this path can not be modified

Eg. TMJ articulatorDesigned by Kenneth Swanson in 1965 Intraoral registration is generated by Studs in auto polymerizing

resin called as stereographic recording this record is placed on the articulator and used to mold the fossa in auto polymerizing resin which produces accurate analog of patients TMJ


CLASS IV TYBE B

These instruments will accept three dimensional dynamic records and utilize face bow transfer. The condylar pathways can be selectively angled and customized


Arcon vs non arconCondylar articulator or non arcon articulator has Condylar element attached to the upper member of the articulator & condylar guidance attached to the lower member of the articulator. Eg. Hanau H series, Dentatus, Gysi

.


Term coined by Bergstrom in 1950Arcon means ARticulator and CONdyle An Arcon articulator has Condylar

element attached to the lower element of the articulator and condylar guidance attached to the upper member of the articulator

Resembles the TMJ eg. Hanau University series, Whip mix

Arcon provides greater accuracy in the transfer of angle of condyle descent by the protrusive positional record But in non arcon instrument the condyle will move distally in protrusion so this distance will be doubled


Weinberg concluded that this doesn’t cause any significant difference

Logically in complete denture construction while balancing the occlusion the incisal angle will appear steeper on the non arcon articulator which is normal in patients mouth

a b

x x

2x

2x


SUMMARYThe frequently asked question is which articulator to be used can be best answered vaguely that how much do you know about it…..

Amount of information required from your patient

Amount and type of restoration planned

Availability of equipments

Late Carl O Boucher stated that it must be recognized that the person operating the instrument is more important than the instrument used.

Success or failure of a final restoration us more depends on dentist rather than the articulator used



www.asiandentalacademy.orgAbove KFC Restaurant main Road Hyderabad

http://www.asiandentalacademy.org/

articulators in complete dentures by #asiandentalacademy

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