articulators part2

ARTICULATORS-II

CONTENTS

• Basic parts of an articulator• Individual articulators• Recent advances• Care and maintenance of articulator• Conclusion• References

BASIC PARTS OF AN ARTICULATOR

• Upper member• Lower member• Mounting plates• Condylar analogues• Condylar guidance• Incisal guide pin• Incisal guide table

UPPER MEMBER Represents maxillaLOWER MEMBER Represents mandibleMOUNTING PLATES Casts are connected

CONDYLAR GUIDANCE

• Represents slopes of articular eminance.• Can be adjusted according to the records

obtained from the patient.• If sloped antero-posteriorly – horizontal

guidance.

• If sloped laterally- lateral guidance.

CONDYLAR ANALOGUES/ELEMENTS

• Spherical in shape• Represents condyle.• If attached to lower member- ARCON• If attached to upper member-

NONARCON

INSICAL GUIDE PIN:-

Acts as an anterior vertical stop & maintains the vertical dimension.Can be flat or rounded.

INCISAL GUIDE TABLE :-

9

INDIVIDUAL ARTICULATORS

Mean-Value Articulator Hanau articulatorsWhip – mix articulator Denar articulatorTMJ articulator

MEAN VALUE ARTICULATOR

• so called because it has 3 fixed mean values

• intercondylar distance-100–110mm • condylar guidance-33degrees• incisal guidance-9-12degrees

PARTS:-• upper member• lower member • insical guide table• vertical rod / incisal pin• Insical guide pin • condylar guidance

• Upper member :-• Triangular frame• Two Condylar elements • Vertical Rod with a thumb screw.

• Lower Member :- L Shaped frame with horizontal and vertical arm.

Horizontal arm is triangular and its apex contains incisal guide table.

Vertical arm is rectangular containing condylar guidance slot at upper portion.

Incisal guide table :- very short cylinder, concave upper surface.

Vertical Rod or Incisal Pin :- keep fixed distance between the upper & lower member at anterior end.

pointed tip - rest on the center

Incisal guide pin :-

anterior reference point.

The incisal edge of the maxillar incisors at the mid line of the occlusal rim should touch the tip of incisal pin during articulation.

Condylar guidance

Represent by a slot (condylar track)

Condylar element of upper member passes through this track.

A spring is mounted within this track to establish the condylar element

Hanau H2 articulator Hanau ARCON H2 articulator Hanau wide VUE articulator. Hanau wide VUE II articulator Hanau Radial shift

HANAU ARTICULATORS

HANAU H2 (Model 96 )

Designed by Rudolph Hanau. It is non-arcon type articulator. It has a fixed intercondylar distance of

110 mm & accept a face-bow transfer. Horizontal condylar guidance: - 40 to

+800

Lateral condylar guidance:- 0 to 200

Four different face-bows can be utilized 1. Facia face-bow

2. Earpiece face-bow 3. Twirl face-bow 4. Adjustable axis face-bow.Has mechanical incisal guide table – adjustable both in sagittal & frontal planes. Some have extendible condylar shafts –

indicated by an “X’’ after the model designation , ex: H2 - X

HANAU ARCON H2 ARTICULATOR

(model 158)• Introduced by HANAU in 1977.• Arcon type.• Special face bow is available.• Pantacrylic incisal guide table

also available.

Hanau wide VUE articulator Upper member Lower member Condylar guidances Dual end incisal pin Adjustable incisal guide table Orbitale indicator Mounting plates

Horizantal guidance

Lateral guidance

Condylar guidance:- Condylar Guidances - control centers of the

Articulator adjustability assimilate the multiple function of

the glenoid fossa.Condylar track - “zero” to a plus 60 degree or to

a minus 20 degree which is inclined on the horizontal transverse axis.

Termed as protrusive inclinationSimulate the patients superior wall of the fossa.

• The Condylar Track – adjustable from “zero” sagittal to 30 degree on vertical axis

• Termed as progressive Bennet angle & simulate the medial wall of patient’s fossa.

• Some have Centric Stop at the posterior end of the Track.

When the Element rests against the Stop it is at centric, the point from which the protrusive or Bennett angles both emanate. Engagement of a Centric Lock arrest the Condylar Element at the centric position and allows freedom of movement when released.

• The Condylar Shafts adjustably slide in the “wings” of the Lower Member fixed by setscrew.

• Resilient bumper – protects upper member by resting it on wings when fully opening the articulator.

DUAL END INCISAL PIN:- serves as the forward control of the Articulator.Maintains a vertical stop and provides a stylus

contact with incisal table during various excursive movements.

Dual end- spherical & chisel tip.Spherical tip – to fabricate Customized acrylic anterior guide tables

A mid-line groove - one inch from the spherical tip. Five additional lines calibrated in millimeters extend on either side thereof.These lines are used for recording or altering the vertical dimension.

Two annular grooves on the Incisal Pin at 37 and 54 mm

below the Frankfort Horizontal Plane. Arbitrary vertical landmarks – alignment of the incisal edge of the maxillary centrals when making a Facebow transfer.

Third point of stability

ADJUSTABLE INCISAL GUIDE TABLE:-• provides adjustment of anterior guidance.• Adjustable both in sagittal & frontal planes.• Sagittal- horizontal 0º to 60º positive inclination of protrusion by the small Locknut. • lateral wings -to 0º to 45º incline by a Thumbnut.

Orbitale Indicator :-represents the patient’s infra-orbitale

notch anterior reference landmark of the Frankfort Horizontal Plane.when used with an orbitale pointer on a facebow, it provides an anatomical vertical orientation for upper arch.

Mounting plates• To attach upper and lower casts to

upper and lower members of articulator.

• Has elongated luting slots – for a secure adherence of gypsum mounting.

• Center domed brass insert which is internally threaded for attachment to upper and lower members .

ARTICULATOR PREPARATION• Adjust the protrusive inclination of both Condylar

Guidances to 30 degrees and tighten the Thumbnuts.

• Adjust the Bennett Angles of both Condylar Guidances at 30 degrees and tighten their thumbnuts. 

• Adjust the Incisal Pin to align the mid-line calibration to the top edge of the Upper Member. 

• Adjust the Incisal Guide to a “zero” degree and tighten the small Locknut.

• Slide the Platform to align the Incisal Pin contact over the “zero” indicating line on Guidance and tighten Platform Lockscrew.

MOUNTING PROCEDURE

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.

• Ear piece - attached to the roll pin of the articulator.

• Transfers the posterior reference point of the face-bow to the articulator.

• Anterior reference point - positioned by making the orbital indicator contact the orbital pointer of the face-bow.

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

Centric lock is engaged.

Later tentative jaw relations is carried out according which the mandibular cast with occlusal rim is articulated.

Then tracers are attached such that central bearing plate to lower and central bearing pointer to upper rim and tracings was carried out.

• And also centric and protrusive records are made.

• Now mandibular cast Is dearticulated.

• Now by placing the centric interocclusal records on mandibular rim, again mandibular cast is articulated in exact centric relation with the maxilla.

PROGRAMMING THE ARTICULATORBefore teeth can be arranged, the articulator

must be programmed or customized to the individual patient.

The programmed articulator is vital to plan an occlusion which is both efficient and at the same time reduces stresses transmitted to the underlying tissues and temporomandibular joints.

PROGRAMMING THE CONDYLAR GUIDANCES

HORIZONTAL CONDYLAR GUIDANCE OR INCLINATION

USING PROTRUSSIVE INTEROCCLUSAL CHECK RECORDS

A protrusive inter occlusal record (ask the patient to protrude the mandible around 6mm) is made by using

bite registration material.The condylar lock nuts on articulator are loosened

and the occlusal rims with record is placed on the articulator.

The condylar inclinations are adjusted until the upper and lower occlusal rim seat firmly and evenly in the protrusive record.

The degree of inclination is noted and recorded on the mounting plaster.The condylar inclination lock nuts are then secured.

LATERAL CONDYLAR GUIDANCE INCLINATION

Using lateral interocclusal records or by Using Hanau’s formula• L=H/8+12.

PROGRAMMING INCISAL GUIDANCE:-

The incisal guide table has a horizontal as well as lateral adjustment.

Both are set to the minimum required for the esthetic needs of the anterior teeth.

Hanau wide VUE II articulator

• The only difference between Hanau wide vue & vue II that the wide vue II has an open condylar track.

• The closed condylar track does not allow the upper member to be removed, Whereas the open condylar track allow the upper member to be removed for waxing.

HANAU RADIAL SHIFT It is an Arcon instrument with a fixed intercondylar

distance of 110mm. It has right & left Centric Latches & the upper

member is easily removed for waxing.Condylar guidance incorporates a curved

immediate side shift with an adjustable progressive Bennet angle.

Radial shift – has 3mm radius & allows up to 3mm of radial shift.

Guidance – has curved superior wall with a 0.75-inch radius

Designed by Dr. Charles Stuart in 1963.

It is an arcon articulator.

The upper & lower member are mechanically attached by means of a spring latch assembly.

WHIP-MIX ARTICULATOR

The original model is 8500.The condylar elements on the lower frame &

adjustable to three positions.

1. Small (S) – 96 mm 2. Medium (M)–110m 3. Large (L) – 124 mm.

• Horizantal condylar inclination – 0 to 70 degrees• Lateral – 0 to 45 degrees.

• Horizantal - by obtaining protrusive/ lateral interocclusal record.

• Bennet angle – by lateral interocclusal records.

• Mechanical/plastic incisal guide table with dual end incisal pin.

Two Different face-bows can utilised:-

1) Quick mount or earpiece face-bow for complete denture.

2) The adjustable axis for fixed prosthodontics. Ear piece- anterior support is attained by placing

plastic block into the deepest part of the Nasion .The plane of reference is automatically created

25mm below the nasion.This plane approximates very closely the axis –

orbital plane.

Articulator model 9000 is similar to model 8500 except the lower frame is ½ inch taller to provide more space for mounting the mandibular cast.

Model 8800 provides an additional ½ inches space to mount the maxillary cast.

This is more suitable in situations with extremely steep plane of occlusions or where osseous defect exist in maxilla.

MODIFICATIONS

Model 9800 is combines the upper frame of model 8800 with the lower frame of model 9000 to provide the greatest distance between the upper & lower frames.

Model 8300 assure that cast can be interchanged between articulators.

DENAR ARTICULATORS In 1968, Dr. Niles Guichet introduced the Denar

D4A articulator and recording system.

D5A – current model.

• Adjustments to the guidance surfaces are possible in all three planes of space.

DENAR MARK II (1975) Arcon type The articulator is a two piece instrument

incorporating a positive locking mechanism that can hold the two members together by means of centric latch.

intercondylar distance - 110 mm however an adjustable distance 110 to 122 mm option is available.

Four types of face-bow can be used :- - Facia face-bow - Earpiece face-bow - Slidematic face-bow - Adjustable axis face-bowHorizontal inclination - 0 to 60 degrees. immediate side shift (Bennett) adjustment of 0 to

4 mm plus a progressive shift adjustment of 0 to 15 degrees

The mark II can be programmed using anatomic averages positional records or with a mini recorder.

It is a newest Denar articulator.

The design allows one to easily exchange closed fossa for open fossa with a positive locking latch.

The purpose of this model is an attempt to better meet the requirements for complete, removable and fixed partial denture fabrication in one articulator.

OMNI ARTICULATOR (1984)

When the articulator is equipped with the open fossae which is identical to mark II fossa it is called omni mark.

When it is utilized with closed track fossa called omni track.

TMJ ARTICULATOR

Designed by Kenneth Swanson in 1965 .

The articulator has a spring loaded latch to help return the upper frame to the centric relation position.

There is curved incisal guide pin with both a plastic & adjustable mechanical incisal guide table.

Custom analog fossae are formed from intraoral sterographic tracings. Specific custom trays (clutches) are prepared:- - four studs in upper clutch - central bearing pin at the centre on lower

clutch. custom acrylic resin is placed on lower clutch. Four functional rhomboid recordings results. Recordings are transferred to the articulator.

A Smaller version of the articulator is available & is called the Mini - Articulator.

Its intercondylar distance is limited from 11o – 150 mm & has a straight incisal guide pin.

RECENT ADVANCES

• Virtual Articulators are also called as `SOFTWARE articulators`.

• They comprises of virtual condylar and incisal guide planes.

• Guide planes can be measured precisely using jaw motion analyser or average values are set in the program like average value articulator

• The Virtual Articulators are able to design prostheses kinematically.

• They are capable of simulating human mandibular movements

• by moving digitalized occlusal surfaces against each other and enabling correction of digitalized occlusal surfaces to produce smooth and collision-free movements.

• Presently Virtual Articulator is supporting mechanical articulator in better visualizing of the occlusion, in near future they replaces mechanical articulators.

CARE AND MAINTAINENCE OF AN ARTICULATOR

LUBRICATION

Light application of quality hand piece oil Excess oil should be wiped off Thin coating of petroleum jelly-when in

contact with gypsum.

CLEANING :- Use a mild soap and water solution with the aid

of a brush to dissolve accumulations of wax and to wash away plaster remains.

Then air dry and lubricate.

DO NOT use strong detergents, alkalies etc..,

CONCLUSION . 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.”

Winkler Sheldon: Essentials of complete Denture Prosthodontics, 2nd edition, p 142-182.

Heartwell Cm Jr, Rahn AO : Textbook of complete dentures, 4th edition, p-51-93.

IJDSR- vol-30, july 2012-articulators in dentistry

Boucher’s:prosthodontic treatment for edentulous patients complete dentures and implant supported prostheses,12th edition ,p-291-296.

J. Thomas: A classification of articulators. J Prosthet dent 1973; 30:11-14

The history of articulators: A perspective on early years, part II JPD 1999 vol 8 – page 277-280.Classification of articulators JPD 1980, Vol 3, page 344.

Edgar N. Starcke, DDS The History of Articulators: A Critical History of Articulators Based on Geometric

• Donald L Mitchell and Noel D Wilkie: Articulators through the years. Part I up to 1940, J Prosthet dent 1978; 39:330-338.

• Lawrence A. Weinberg: An evaluation of basic articulators and their concepts. Part II. J Prosthet dent 1963; 13:645-663.

• Awni Rihani: Classification of articulators. J Prosthet dent 1980; 43:344-347.

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