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11/29/2013ARTICULATOR1/29/2013ARTICULATORS43

Hinge Joint ArticulatorBack1/29/2013ARTICULATORS39

Gysis Mean ValueHouses ArticulatorMonsons ArticulatorHalls ArticulatorBack1/29/2013ARTICULATORS4Pioneers in the development of Articulator DesignsFerdinand Graf von Spee (1855-1937)

George S. Monson, DDS (18691933)

Alfred Gysi1/29/2013ARTICULATORS5

George Monson demonstrated his spherical theory for the first time on this Bonwill articulator. The casts were mounted in the articulator according to Bonwills equilateral triangle and with the spherical occlusion guide.1/29/2013ARTICULATORS6

Christensens Rational articulator with plaster casts and wax occlusion rims mounted in the centric position. The plaster blocks, mounted for the simulated functional generated path procedure, would look similar to this.1/29/2013ARTICULATORS7

(A) Christensens Rational articulator withthe condylar guides set at a high inclination. The maxillary and mandibular plaster blocks have been manually ground in and the surfaces have obtained spherical shapes. (Reprinted from Christensen.12)

(B) Vulcanite rubber stints with wax occlusion rims on casts of badly worn natural teeth. The spherical contours of the rims were formed as a result of the subject moving his mandiblefreely and as far as capable while maintainingcontact of the rims with moderate pressure.1/29/2013ARTICULATORS8

Monsons Mandibulo-Maxillary instrument. Point A is the radial center of the instrument from which the occlusal surfaces of the teeth are determined. Point B is the position of the condylar hinge mechanism for the instrument. The teeth are arranged to conform to the 8-inch sphere at C. Slot D controls anteroposterior movement. The slot is concentric with the outer surfaceof the sphere. Jackscrews E are used to adjust the position of the lower cast to the center if required. This instrument was manufactured by M.F. Patterson Supply Co., St Paul, MN. (Reprinted from Campbell.21)

1/29/2013ARTICULATORS9Purpose of an Articulator To hold the maxillary and mandibular casts in a determined fixed relationship.

To stimulate the jaw movements like opening and closing.

To produce border movements (extreme lateral and protrusive) and intraborder movement(within the border movement) of the teeth similar to those in the mouths1/29/2013ARTICULATORS10Uses of an Articulator To diagnose the state of occlusion in both the natural and artificial dentitions.

To plan the dental procedures based on the relationship between opposing natural and artificial teeth. E.g. : evaluation of the possibility of balanced occlusion

To aid in the fabrication of restorations and prosthodontic replacements

To correct and modify completed restorations

To arrange artificial teeth

1/29/2013ARTICULATORS11Requirements of an ArticulatorMinimal Requirements :It should hold the casts in the correct horizontal and vertical relationship.The cast should be easily removable and re-attachable.It should provide a positive anterior vertical stop (Incisal Pin)It should accept face-bow transfer record using an anterior reference pointIt should open and close in a hinge movementIt should be made of a non corrosive and rigid materials that resist wear and tear.It should not be bulky or hayThere should be adequate space present between the upper and lower membersThe moving parts should move freely without any frictionThe non-moving parts should be of a rigid construction.1/29/2013ARTICULATORS12Additional Requirements:The condylar guides should allow protrusive and lateral jaw motionThe condylar guide should be adjustable in a horizontal directionThe articulator should be adjustable to accept and alter the Bennett movementThe Incisal guide table should be customizable (allow modification)

1/29/2013ARTICULATORS13Advantages of ArticulatorsProperly mounted casts allow the operator to visualize the patients occlusion especially from the lingual view.Patient co-operation is not a factor when using an articulator once the appropriate inter-occlusal records are obtained from the patient.The refinement of complete denture occlusion in the mouth is extremely difficult because of shifting denture bases and resiliency of the supporting tissues. The difficulty is eliminated when articulators are usedReduced chair time patients appointment timeThe patients saliva tongue and cheeks are not factors when using an articulator.1/29/2013ARTICULATORS14Limitations of an ArticulatorAn articulator may be made of metal or plastic. Metal articulators show errors in tooling(manufacture) or errors resulting from metal fatigue.The articulator may not exactly simulate the intra-border and functional movements of the mandibleErrors in the jaw relation procedures are reproduced as errors in the denture occlusion. Articulator do not have any provision to indicate or correct these errors1/29/2013ARTICULATORS15Classification BASED ON THEORIES OF OCCLUSIONBASED ON THE ADJUSTABILITY OF THE ARTICUALTORBASED ON TYPE OF INTER-OCCLUSAL RECORDSBASED ON THE ABILITY TO SIMULATE THE MOVEMENTS 1/29/2013ARTICULATORS16Articulators based on Theories of OcclusionBonwill theory articulatorThis articulator was designed by WGA Bonwill.According to this theory the teeth move in relation to each other as guided by the condylar and the Incisal guidance.Also known an Theory of equilateral triangle whose dimension is 4 inches.Bonwill articulators allow lateral movement and permit the movement of the mechanism (joint) only in the horizontal plane.1/29/2013ARTICULATORS17

1/29/2013ARTICULATORS182. Conical theory articulatorsProposed by R E HallThe conical theory of occlusion proposed that the lower teeth move over the surfaces 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 occlusal plane.The Hall Articulator follows this theory.

1/29/2013ARTICULATORS193. Spherical theory articulatorsThe spherical theory of occlusion proposed that the lower teeth move over the surface of upper teeth as over the surface of sphere with a diameter of 8 inches.The centre of the sphere was located in the region of the glabella. The surface of the sphere passed through the glenoid fossa and along with the articulating eminences.The articulator devised by G S Monson operated on this theory

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Dr. Monson making measurements on a human mandible to demonstrate that from the 4-inch common center, the divider touches the Incisal edges and the condyles.1/29/2013ARTICULATORS21

A frontal view of the mandible illustrating the relationship of the 8-inchdiameter sphere with the transverse plane of occlusion that Monson claimed must be the same as the anteroposterior plane for balanced occlusion to be achieved. The radial lines of force of 4-inch length converge forming the radial point at the apex from which the radius of occlusion of each tooth is determined. (Reprinted from Monson.20)1/29/2013ARTICULATORS22

A posterior view of the mandible, illustrating the application of the radial lines to the condyles. The center of the condyles areshown conforming to the surface of the sphere, giving the same radial dimensions from the centers of the condyles to the apex as from the occlusal surfaces of the teeth. This also illustrates Monsons concept that this radial center is the center for theentire muscular action because the angles of the mandible conform to lines centering at apex A. (Reprinted from Monson.20)1/29/2013ARTICULATORS23Disadvantages Articulators are based on theoretical conceptsThere is no provision for variation from the theoretical relationships that occur in different planes

1/29/2013ARTICULATORS24Articulators Based on the Type of record used for their AdjustmentThey are classified as:Inter-occlusal record adjustment : made of Base plate wax ;plaster of paris; zinc oxide eugenol paste or cold cure acrylicGraphic record adjustment: Use of a Transgraphic record; the Face-bow and Jaw-writing apparatus

Transographic Jaw Recorder and Duplicator1/29/2013ARTICULATORS25Based on the Ability to Simulate Jaw Movements Class I : Hinge Type - ( Slab articulator, Hinge joint articulator GARIOT (1805), Barn door articulator )Class II : Arbitrary type A (Mean-Value articulator - GYSI) type B (Monsons articulator , Hall articulator) type C (Houses articulator )

Class III : Average - type A (Hanau H articulator- RUDOLPH HANAU (1923) Hanau H2 articulator Bergstrom articulator (ARCON) )

type B (Stansberrys Tripod - Stansberry Ney articulator - De Pietro (1960) Tele Dyne articulator - Richard Beu (1975) )

Class Iv : Special type A (TMJ articulator Kenneth Swanson (1965) ) type B (Pantronic acticulator Dener (1982) Gnathoscope - Charles Stuart )

1/29/2013ARTICULATORS26Based on AdjustabilityClassified into 3 types :Non Adjustable (Mean Value )2. Semi Adjustable : It is further classified into 2 types - Arcon Type (Whip mix) Non arcon Type (Hanau H)3. Fully Adjustable (TMJ)

1/29/2013ARTICULATORS27Mean Value ArticulatorAlso called as Three Point Articulator or Free Plane ArticulatorThese instruments are routinely used in dental colleges to teach undergraduate students. These instruments are nonadjustable, non arcon type, designed using fixed dimensions. A spring is mounted within the condylar track to stabilize the condylar elements and hold them in their posterior most position .The articulator is designed using fixed dimensions.

The Mean Values are:Fixed Condyles with radius of 19mm.Mean Condylar Inclination : 35Bennett angle adjustment : 0-20

1/29/2013ARTICULATORS28Parts of an ArticulatorUpper memberLower memberVertical rodIncisal pinIncisal guidance tableSighting rodHorizontal bar/rod

1/29/2013ARTICULATORS29Selection of an ArticulatorOne should not used too complex instruments for a simple case or too simple articulator for a complex caseThe following factors pertinent to the understanding and selections : Articulator movements of the condylar elements do not reproduced condylar movement in the temporomandibular joint.

The goals of articulation is to duplicate tooth movements along border path ways in at least two planes of space.

The most important requirement of an articulator are to maintain centric relation & the vertical dimension of occlusion.

1/29/2013ARTICULATORS304. . Fixed condylar elements at 110mm are all that is necessary. An adjustable inter condylar capability may permit more records to be accepted.

5. The articulator should be able to receive a face-bow transfer record,.

6. The articulator should have the capability of adjustment for precurrent or immediate side shift upto at least 2.5 mm.

7. An adjustable mechanical Incisal guide table can not reproduce the natural guidance of the anterior teeth.

8. A sterograph ( pantograph) has limited value for all but a few types of prosthodontic situation.

9. The sophistication of articulators should not exceed the level of training & ability of the personnel that will be fabricating the restorations.

1/29/2013ARTICULATORS31Mounting ProcedureMaxillary cast :

Maxillary cast is attached to the articulator using the orientation jaw relation record.

Procedure of transferring the orientation jaw relation to the articulator is called face-bow transfer.

The ear piece of the face bow is attached to the rollpin of the articulator

This transfers the posterior reference point of the face-bow to the articulator

The anterior reference point should be positioned by making the orbital indicator contact the orbital pointer of the face-bow.

A pivot stand attached to the lower member of the articulator also helps to prevent vertical displacement of the occlusal rim during articulation.

1/29/2013ARTICULATORS32Mandibular cast :Tighten the centric lock on each enclosed condylar track mechanism to ensure that the articulator is capable of nothing but a hinge opening.

Invert the articulator on the bench top resting it on the three thumb nuts protruding from the upper member of the articulator.

Place the centric relation interocclusal wax record on the teeth of maxillary cast. Be sure that the teeth seat completely into wax record.

Place the mandibular cast into interocclusal record.There should be no contact between the maxillary and mandibular cast.

Remove the mandibular cast and soak it for about 2 minute in slurry water.

Reseat the soaked mandibular cast into the record and mount it by plaster/stone.

1/29/2013ARTICULATORS33Inspect the Articulated castThe condyle is in the retruded position in its condylar track mechanism.Both casts are seated completely in the interocclusal wax record.Mounting stone is securely attached to both casts and mounting plates.

1/29/2013ARTICULATORS34ConclusionThe choice of articulator depends upon such factors as :intended use, availability of equipment, patient's occlusion, skill of the technician, skill of the operator, expense

No existing articulator will reproduce all mandibular movements exactly, nor is this its primary objective. The goal is to make restoration with occlusal morphology compatible with the movements of mandible. The more closely the articulator matches the patients anatomy, usually the better the outcome and the less adjustment is required at chair-side on fitting prostheses. The late Carl O. Boucher summed up the articulator controversy by stating, It must be recognized that the person operating the instrument is more important than the instrument. If dentists understand articulators and their deficiencies, they can compensate for their inherent inadequacies.

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Denar Articulator

TMJ ArticulatorOther Commonly Used Articulators1/29/2013ARTICULATORS36

Hanau Wide Vue 2

Artex Mean Value 1/29/2013ARTICULATORS37

Whipmix ArticulatorHanau H2 Articulator

1/29/2013ARTICULATORS38Bibliography Kathmandu University Medical Journal (2008), Vol. 6, No. 1, Issue 21, Deepak Nallaswamy the text book of Prosthodontics,first edition.Journal of Prosthodontics, Vol. 11, No 2 ( June), 2002: pp 134-146Archive of University of TexasCharles M. Heartwell the syllabus of complete denture, fourth edition.Sheldon Winkler- the essential of complete denture prosthodontics,second edition.