History of Articulator

TOPICS OF INTEREST

History of Articulators: Henry L. “Harry’’ Pageand the TransographRobert L. Engelmeier, DMD, MS1 and Edgar N. Starcke, DDS2

The intention of this article is to introduce the reader to the Transograph from a historicalperspective. The technical data presented are intended to help the reader understand the designof this unique instrument and how it was programmed, but will not provide the reader a thoroughunderstanding of this philosophy. The article seeks neither to defend nor criticize the principles ofTransographics.

J Prosthodont 2006;15:374-380. Copyright C© 2006 by The American College of Prosthodontists.

INDEX WORDS: transograph, transographics, Harry Page, gnathology, articulator

TRANSOGRAPHICS was a philosophy of ar-ticulation essentially based on gnathological

principles, but which made a bold departure inthe practical application of those principles. Inhis writings, Harry Page1 recognized the Gnatho-logical Society of California for advancing soundprinciples of jaw function as early as 1926. Heargued, however, that the application of thoseprinciples, along with the necessary instrumenta-tion, had become so complicated that much con-fusion and indifference toward the GnathologicalSociety’s work had resulted. Page claimed, “Thedevelopment of Transographics was an effort toapply the original Gnathological principles withmore direct and efficient methods thereby yieldingsuperior results.’’1 He passionately believed thatarticulation and the “duplication’’ of mandibularmovement were engineering problems solvable byexisting technology. His theory of Transographicsstood on two basic principles. First was his convic-tion that the “first point of contact’’ upon closurein any individual mouth was always precisely thesame. Second was his belief that only the lastfew millimeters of final closure were importantin assuring an accurate cusp to fossa occlusion.2

1Director, Graduate Prosthodontic Program, Department of

Prosthodontics, University of Texas, Houston, TX.2Clinical Professor, Department of Prosthodontics, University of

Texas, Houston, TX.

Correspondence to: Edgar N. Starcke, University of Texas Health

Science Center – Houston Dental Branch, 6516 M.D. Anderson Blvd.,

Houston, TX 77030. E-mail: [email protected]

Copyright C© 2006 by The American College of Prosthodontists

1059-941X/06

doi: 10.1111/j.1532-849X.2006.00128.x

Page’s enthusiasm for the Transograph artic-ulator was matched only by his denunciation ofmost other instruments of the time. His criticismfocused on what he believed were their threegreatest design flaws:

1. Ball and socket condylar controls,2. A solid intercondylar axis, and3. Non-arcon design.

The theory of Transographics was based uponfour basic determinants—Page’s four major prin-ciples of “Functional Articulation:’’1

1. The Temporomandibular Joint Center of Ro-tation (i.e., The Hinge Axis),

2. The Cranial Reference Plane (i.e., The AxisOrbital Plane),

3. Collateral Bodily Shift of the Mandible in Func-tion (i.e., The Bennett Movement), and

4. The Envelope of Motion.

Because he believed static jaw positions couldnot define function,3 Page sought to record thefour determinants, use them to program the Tran-sograph, and “accurately duplicate a patient’sfunctional jaw movements.’’ The Kinetic Princi-ples, which Page believed governed mandibularmovement, dismissed static jaw relation records,which historically had been used to articulate castsand program dental articulators, e.g., CentricRelation, Protrusive, and Lateral Records. TheTransograph (Fig 1)4,5 was programmed either bymeans of a pantographic tracing or a series of posi-tional records which defined the arc of movementaround each of the three axes (passing througheach rotation center). Page claimed that the force

374 Journal of Prosthodontics, Vol 15, No 6 (November-December), 2006: pp 374-380

November-December 2006, Volume 15, Number 6 375

Figure 1. The U.S. PatentOffice awarded the Transo-graph Patent #2,982,025 in1961, along with the trade-mark “Jaw Recorder andDuplicator.’’ The theory ofTransographics, in princi-ple, actually promoted veryfew new ideas; however, theinstrument and how it ap-plied these concepts was anentirely new and controver-sial departure.22

and direction of jaw movement were under thecontrol of “Kinesthetic Proprioceptors,’’ found inthe muscles, ligaments, and joints.3

Principles of “FunctionalArticulation”

The Temporomandibular Joint Centerof Rotation

In his writings, Page1,3,6-13 argued that each tem-poromandibular joint had its own horizontal axisof rotation. He theorized that these individual

axes did not line up with each other becauseof asymmetries in joint anatomy and location ofthe joints on either side of the head. He insistedthat the condyles could shift (in any direction) tocompensate for these discrepancies. He liked tocompare the joints with self-aligning bearings.Even though the design of nearly all articulatorsdeveloped over the previous century had beenbased on the existence of a Transverse HorizontalAxis, Page did not believe in this concept. Instead,he believed that each joint had its own vertical,sagittal, and horizontal axes. He held that an axiswas always perpendicular to the path of rotation

376 History of Articulators • Engelmeier and Starcke

Figure 2. Lower member of the Transograph used asan axis locator (Copyright Quintessence Publishing Co. Inc.).

that it controlled, and that the three axes thatpassed through each condyle did not intersect at asingle, common point, (i.e., they were not mutuallyperpendicular). Page described all three of theseaxes as intra-fossal (i.e., in the fixed member ofthe hinge), and not intra-condylar.14

Unlike any other articulator, the Transographwas designed with no mechanical connection be-tween the right and left condylar controls. Onlythe mounted casts joined its posterior elements.The instrument itself was slightly flexible, allow-ing the upper and lower members to actually“twist.’’According to the inventor, this “controlledtwisting ability’’ enabled the Transograph to “ac-curately duplicate’’ the bodily shifts of the jaw infunction.14

Trapozzano15 later pointed out that joining theright and left condylar controls with mounted castswas, in effect, no different than joining them bymeans of a solid upper member. He especially tookexception with Page’s claim that Transographicswas founded on sound Gnathological principlesbecause McCollum did, indeed, use a “solid hingeaxis’’ while Transographics refuted this principle.

The lower member of the Transograph wasinitially used as an axis locator and was attached to

the patient’s mandible by means of a clutch linedwith soft plaster (Fig 2).3 Axis location with thisdevice was similar in technique to that employedby most conventional axis locators. Once the axiswas located, the axis points were marked on thepatient. The axis locator was then employed asa transfer bow which, in turn, became the lowermember of the Transograph. Note that the pa-tient’s gonial angle was carefully measured, andthe lower member of the instrument was adjustedto precisely duplicate that angle (Fig 3).13

The Cranial Reference Plane

Page stressed the necessity of selecting and ac-curately transferring a reference plane from thecranium to the articulator to correctly orient theocclusal plane in space. He believed that the oc-clusal plane could only be accurately transferredto an instrument after it had been related toanother reference plane (in the patient’s head)that had already been established in the articu-lator.1,3,6,7,16,17

Page credited past articulator designers Mc-Collum, Wadsworth, Simon, and others for wiselyusing such reference planes, but criticized themfor using planes established by specific landmarks.He believed that the only requirement in cranialreference plane selection was that it could berepeated in the articulator.1,3,7,16,17 For each pa-tient, he used an “individual’’ cranial plane, whichwas defined by the Hinge Axis and any convenientcranial plane reference point. He used his “HeadRelator’’ (Fig 4),16 which he set level with thepupils of the eyes to establish his cranial plane. If apatient had a “long’’ face, he set the “head relator’’below the pupils. If the patient had a “short’’ face,he set the “head relator’’ above the level of thepupils, (i.e., the cranial reference plane did notneed to be exact).16

Collateral Bodily Shift of the Mandiblein Function

In his review of the literature concerningmandibular movement, Page1,3,7,18-22 found twoopposing theories that attempted to explain theBennett Movement. Gnathological writers, (i.e.,McCollum,23 Granger,24 and Lucia25) stated thatthe phenomenon of Bennett Movement was dueto the downward, forward, and inward movement


Figure 3. Measurement ofthe gonial angle and ad-justment of the lower mem-ber of the Transograph toduplicate that angle (Copy-right Quintessence PublishingCo. Inc.).

of the nonworking condyle along the “inner curb-ing’’ of its fossa. A second theory put forth bySicher26 attributed the cause of Bennett Move-ment to the time lag between contraction of the(nonworking) lateral pterygoid muscle and the(working) temporalis muscle.

Though these two theories contradicted eachother, both schools of thought agreed that BennettMovement was a component of lateral movement.

Figure 4. Head Relator used to relate the CranialPlane and Transverse Axes to the Maxillary OcclusalPlane (Copyright Quintessence Publishing Co. Inc.).

Page,18,19 on the other hand, believed that Ben-nett Movement was not a component of lateralmovement. Rather, he held it was a componentof natural, functional movements, the major ofwhich was vertical movement. Page pointed outthat condyles were grossly irregular in shape andsize, and that they moved against irregular fossae.Consequently, he believed all jaw movements, nomatter what type, involved a certain amount ofopening or closing movement. He further pos-tulated that, in order for the jaw to function atall, it had to somehow compensate for the un-equal radii, shapes, positions, and sizes of tem-poromandibular joints. Bodily shifts of the jawat the individual fulcra points, which providedthis compensation, were made possible by looselyencapsulated condyles.1,3

Page felt it next to impossible to build anarticulator capable of duplicating the bodily shiftof the mandible upon opening and closing. Hefurther pointed out that this was a very difficult,expensive, and unnecessary way to address thisproblem.3 He believed that he could duplicateBennett Movement by equivalence (i.e., by us-ing a slightly flexible articulator employing closefitting “pin-in-sleeve’’ bearings as opposed to arigid instrument). He felt that the slightly flex-ible Transograph could twist to compensate forthe misalignment of individual axes present inthe jaw, thereby yielding equivalent movements.Page claimed that transfer of the Transverse Axesmisalignment automatically created a BennettMovement in the Transograph when the right andleft components of the instrument were joined bymounted casts.3


Figure 5. A series of three lateral records of varyingthickness was made on each side. Page believed thisensured independent capture of each of the three axesof each joint (Copyright Quintessence Publishing Co. Inc.).

The Envelope of Motion

A basic tenet of Transographics was that the ar-ticulator needed only to follow a patient’s “enve-lope of motion,’’ and further, that teeth free ofinterferences at the borders of that “envelope ofmotion’’ were automatically free of interferencesat any point within the envelope.1,3,7-9,11,27

Harry Page believed that he could capture the“envelope of motion’’ by locating and reproducingthe control centers. Since he believed that eachcondyle rotated in all three dimensions, he feltit necessary to capture the three rotational axesfor each condyle.27 Page held that the completeenvelope of motion included bruxing positions,which could be very detrimental. So, he focusedon a pattern of non-interfering function lyingsomewhere inside the “envelope of motion.’’ Hefurther believed that pattern to be controlled bythe same axes that controlled the entire enve-lope, and that nothing changed during functionexcept the amplitude of the components ofmovement.1

To ensure independence of the three axes ineach joint, Page made three lateral check biterecords on each side. Each of the three recordswas made at a slightly different position along

the path of lateral movement (Fig 5).28 The rightand left condylar controls of the Transographwere released while the mounted casts were fittedinto the records. That eliminated the influenceof the rotating condyle, as was the case in otherarticulators. Hence, his lateral check bite recordsinfluenced the adjustment of both condylar con-trols (Fig 6).28

Page and his followers believed that condylepaths varied as a result of interfering cusps,prosthodontic appliances, and variations in foodsencountered at the occlusal surfaces of the teeth.Because of this variation in the path they furtherbelieved that it could never be duplicated by anyfixed condyle slot in an instrument.27 They alsoheld that the translating condyle had no set pathsince it had no way of being braced against theeminence throughout its excursions. This beliefwas based on pantographic tracings of the jaw infunction which showed movements of the translat-ing condyle to be erratic.27 Page argued that thetrue pattern of jaw function was quite differentfrom the “boundaries of condylar movements.’’Heasserted that the value of pantographic tracingslay not in finding and transferring movementboundaries of the translating condyle, but in howwell those tracings permitted location and transferof the axes of the working condyle.

Transographics—A Unique Concept

The Transograph was an articulator like no other.Although Harry Page tried to align himself withthe gnathologists, some elements of his theory ofTransographics undoubtedly made many gnathol-ogists cringe. This article has sought neither todefend nor criticize the Transograph or the the-ories upon which it was based. The intention hasbeen to look at Harry Page and his instrument ina historical context.

Though some time has been spent in this ar-ticle explaining some of Page’s theories and howthey were reflected in the Transograph, this wasonly done to assist the reader with enough basicknowledge to make some sense of the constructionand programming of this most unusual articula-tor. It was only through a thorough study of Page’sprolific writings on this topic that any real un-derstanding of Transographics could be reached.His articles were interesting and enthusiasticallywritten, but somewhat confusing. The fact thatHarry Page gave so many demonstrations, clinics,


Figure 6. Each of the lat-eral records influenced thesetting of both condylar con-trols (Copyright QuintessencePublishing Co. Inc.).

and study clubs suggested that even he understoodthe potential difficulty in grasping his conceptsand correctly using the Transograph by simplyreading his articles. He posed some very thoughtprovoking points in his papers. His articles on

Figure 7. Henry L. “Harry’’ Page (circa 1917). Photocourtesy of the Archives of Hotchkiss PreparatorySchool, Lakeville, CT.

centric relation,29 jaw protrusion,30 and balancedocclusion31 certainly added to the controversy15,32

spawned by his other articles. His enthusiasmwas all too obvious in his “Envelope of Motion’’article.27 In it he boldly proclaimed his beliefswith a confidence akin to that of Bonwill, whoseproclamations seemed to be divinely inspired. Hisarticles were also full of many practical and un-derstandable analogies. Some of his terminology,if not professionally correct, was nonetheless col-orful and easily understood (e.g., he referred topara-functional movements as “doodleing’’18).

Epilogue

Alas, the Transograph did not withstand the test oftime and has all but slipped into obscurity. Surviv-ing instruments have been abandoned to displayin articulator collections where curious studentsgaze upon them and scratch their heads in wonderat how in the world the thing worked. Nonethe-less, Harry Page did make a great contributionto dentistry. The lively debates which his ideasand prolific writing stimulated, have undoubtedly,brought the profession to a greater understandingof the dynamics of the impression procedure andmandibular movement.33

Author and InventorHenry L. “Harry’’ Page was a native of Connecti-cut who received his formal education at the


Hotchkiss Preparatory School (Fig 7) and YaleUniversity. His college years were interrupted byWorld War I. During the war, he served as a flyingofficer (both as a pilot and as a flight instructor).Following the war, he completed his formal train-ing and embarked on a career as a heat exchangeengineer. His sojourn into dentistry began at aluncheon in 1937 when two Los Angeles dentistsexplained to him how most edentulous patientsexperience a stability problem with mandibulardentures. His intense interest in using physics andengineering principles to solve this challengingproblem led to the development of the mucostaticimpression technique. Later in 1950, with the co-operation of Dr. Rubin N. Albinson of Minneapo-lis, he established the concept of Transographics.He devoted over 30 years to dental research andteaching the practical application of Mucostaticsand Transographics. He contributed numerousarticles to the dental literature concerning both ofthese philosophies. Many of his articles have beentranslated into foreign languages. He lectured atmany study groups, Academy meetings, and dentalschools across the United States.1,3

References

1. Page HL: Fundamentals of practical articulation. Dent Dig1959;250-254

2. Page HL: Transographics—a summary. J Colo Dent Assoc1969;47:36.

3. Page HL: Transographic duplication of jaw function usingkinetics—Reprint Part I. TIC Magazine, 1963:12:9-2-5;Part II. TIC Magazine, 1963:12:10:5-9; Part III. TICMagazine, 1963:12:11:3-5; Part IV. TIC Magazine,1963:12:12:13-16; Part V. TIC Magazine, 1964:13:1:14-15; Part VI. TIC Magazine, 1964:13:2:5-11. TiconiumDiv/CMP Industries, Inc., 1964.

4. Page HL: Dental instrument. U. S. Patent No. 2,982,025,May 2, 1961.

5. House JJ: The design and use of dental articulators in theUnited States From 1840 to 1970—Thesis. Indianapolis,Indiana University, 1970, pp. 210-214

6. Page HL: Temporomandibular joint physiology and jawsynergy. Dent Dig 1954;60:54-59

7. Page HL: Transographics and the transograph: Part I.Dent Dig 1956;62:162-167

8. Page HL: Transographics and the transograph: Part II.Dent Dig 1956;62:214-219

9. Page HL: Some confusing concepts in articulation: Part I.Dent Dig 1958;64:71-76

10. Page HL: Some confusing concepts in articulation: Part II.Dent Dig 1958;64:120-124

11. Page HL: Hinge-axes: arguments and typical examples:Proof: Part I. Dent Dig 1960;66:368-372

12. Page HL: Hinge-axes: arguments and typical examples:proof: Part II. Dent Dig 1960;66:411-415

13. Page HL: The hinge bow. Dent Dig 1952;58:534-53714. Page HL: Fundamentals of practical articulation. Dent Dig

1959;65:250-25415. Trapozzono VR: Discussion of the transograph and tran-

sographic articulation by Jerome M. Schweitzer, D.D.S. AJ Pros Dent 1957;97:622-624

16. Page HL: The cranial plane. Dent Dig 1955;61:152-15717. Page HL: Natural articulation movements. Dent Dig

1953;59:202-20618. Page HL: The Bennett movement: Part I. Dent Dig

1955;61:344-34919. Page HL: The Bennett movement: Part II. Dent Dig

1955;61:395-39820. Messerman T, Walsh PW: Mid-States Dento-Occlusal

Symposium: concepts of occlusion—transographics andthe evolution of the transograph. Dent Clin of N Am1963;7:637-647

21. Page HL: Transographics principles and practice for tech-nicians: Part I, Principles. National Association of DentalLaboratories 1961;1(8):1-14

22. Page HL: Transographics principles and practice for tech-nicians: Part II, Practice. National Association of DentalLaboratories 1961;1(9):1-16

23. McCollum BB: Oral diagnosis. J Am Dent Assoc1943;30:1218-1233

24. Granger ER: Functional relations of the stomatognathicsystem. J Am Dent Assoc 1954;48:638-647

25. Lucia VO: The fundamentals of oral physiology and theirpractical application in the securing and reproducing ofrecords to be used in restorative dentistry. J Pros Dent1953;3:213-231

26. Sicher H: Positions and movements of the mandible. J AmDent Assoc 1954;48:620-625

27. Page HL: The envelope of motion. Dent Dig 1956;62:358-361

28. Page HL: Lexicography, hinge opening, hinge closing, andcentric. Dent Dig 1955;61:17-23

29. Page HL: A critical appraisal of centric relation. Dent Dig1953;59:342-345

30. Page HL: Temporary protrusion, its causes and correction.Dent Dig 1956;62:20-25

31. Page HL: An appraisal of balance. Dent Dig 1954;60:200-204

32. Schweitzer JM: The transograph and transographic artic-ulation. J Pros Dent 1957;7:595-621

33. Ed. Staff: News of the industry. Dent Lab Review 1941;6:24

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History of Articulator