DENTAL INSTRUMENTATION

The History of Articulators: From Facebowsto the Gnathograph, a Brief History ofEarly Devices Developed for RecordingCondylar Movement: Part IIEdgar N. Starcke, DDS

THIS ARTICLE continues an historical review,begun in the last issue, of landmark clinical

investigations that advanced the profession’s un-derstanding of the nature of condylar movement.The investigators’ unique recording devices, devel-oped for registering and studying the movements ofthe condyles in human subjects, are described.

Contributions of George Campionand Norman Bennett

George G. Campion, of Manchester, England,generally supported the findings of Charles E.Luce and William E. Walker on mandibularmovement. When speaking of the S or ogee formof the condylar paths, however, Campion statedthat the form and variations of the condyle pathsshow how futile the efforts must be to constructan anatomical articulator. He contended that noarticulator could be truly anatomical unless itcould imitate the exact condylar paths of eachindividual patient.1 He believed that J. B. Parfittdeserved the credit for being the first to constructan articulator that embodied this essential prin-ciple. Campion designed an adjustable facebowfixed to the mandibular teeth with modeling plas-tic to graphically record the various positions ofthe condyles on the face with a succession of dots(Fig 1). Using white blotting paper, the dots(made with a thick oil-based dye) were related tothe ala-tragus line with one edge of the paper,lifted off, and transferred directly to either apaper record or a glass lantern slide.

Although Campion did not produce an articula-tor of his own, he was concerned about misconcep-tions relating to the opening axis of the mandibleand the design of that feature in articulators. Hestated that although it had been suggested thatduring the opening movement, the mandible ro-tated about an axis located behind and below thecondyles, he believed this description to be errone-ous. His data showed that there could be no oneaxis about which the mandible travels in openingmovement. He interpreted this movement to becomplex, occurring about 2 axes: 1 approximatelythrough the centers of the condyles (rotation) andthe other through the centers of the curves of the 2articulating eminences (translation). He concluded“. . . the only part of the opening movement whichan articulator is concerned to reproduce is theinitial stage which is seen in the tracings to be asimple rotation about an axis passing through thecondyles.”1

On April 27, 1908, Norman G. Bennett of Lon-don, England presented a paper on mandibularmovement to the Royal Society of Medicine Odon-tology Section. The article, originally published inthe proceedings of the society that year, was re-printed in its entirety in the Journal of ProstheticDentistry in 1958.2

By 1908, Bennett had been studying mandib-ular movement for several years and on thisoccasion wanted to clarify “one or two aspects ofthis thorny problem” that he believed other in-vestigators had not dealt with adequately. Specif-ically, he intended to show that no single fixedrotation center of the condyles exists, but thatthe center is constantly moving. That is, for anynormal opening movement of the mandible, asuccession of instantaneous centers of rotationoccurs in a curved path. The paths vary amongindividuals.

Other observations relating to vertical move-ments of the mandible reported by Bennett in-

Correspondence to: Edgar N. Starcke, DDS, Clinical Professor, De-partment of Prosthodontics, The University of Texas Health Science Centerat Houston Dental Branch, 6516 M.D. Anderson Boulevard, P.O. Box20068, Houston, TX 77225. E-mail: estarcke@mail.db.uth.tmc.edu

Copyright © 2002 by The American College of Prosthodontists1059-941X/02/1101-0011$35.00/0doi:10.1053/jpro.2002.31438

53Journal of Prosthodontics, Vol 11, No 1 (March), 2002: pp 53-62

cluded the existence of a “definite rest position ofthe mandible. . .as judged by subjective sensation” andthat the initial center of rotation of the mandiblewas located behind and below the condyle. Heconcluded, therefore, that altering the vertical di-mension of occlusion on a hinge articulator wouldintroduce errors.2

Bennett’s description of the lateral paths of thecondyles was actually of minor consideration. Es-sentially, the only data from this article that showedthe condylar movements that now bear his name isillustrated in Fig 2 (movements of Bennett’s rightcondyle). Line A is extreme vertical opening withno lateral movement. Line B is extreme openingwith extreme lateral movement to the left. Line B�is that of extreme opening combined with extrememovement to the right. Lines C, C� represent ex-treme lateral movement to the left and right withthe teeth in continuous contact. Bennett’s com-ments were, “[it] is interesting as showing that, inmy case at least, in movement towards the side onwhich the condyle might be expected to remainstationary there is quite considerable movement ofthe condyle outwards away from its articular sur-face.”2

Although Norman Bennett was a well-respectedclinical investigator, it is remarkable neverthelessthat this single case study received so much atten-tion and has been seen as such an important mile-

Figure 1. George C. Campion’s graphic facebow device.Campion’s method of recording the condylar paths in-volved placing a succession of dots on the face and trans-ferring the dots with blotting paper to either paper orglass. (Reprinted from Campion, p 40.1)

Figure 2. An illustration ofextreme opening and lateralmovements of Norman Ben-nett’s right condyle dem-onstrating the phenomenonnow known as the “Bennettmovement.” (Reprinted withpermission.2)

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Figure 3. (A) Professor Alfred Gysi demonstrating man-dibular movement. This is one of the earliest models ofGysi’s mandibular recorders. It was designed to recordthe movements of mandible at the condyles and chin instraight opening and closing. The pencils are pointed torecord in the sagittal plane. The horizontal plates paral-lel the occlusal plane. (Reprinted from Clapp, p 143.9)(B) These recordings showed a downward and forwardpath of the condyle. (The arm and pencil have beenremoved to permit a better view of the condylar path.)Note that the chin path scribed a loop or “teardrop”effect. (Reprinted from Clapp, p 143.9) (C) Professor Gysidemonstrating the lateral movements of the condyles andchin. The pencils are turned to record on the horizontalplane. Gysi showed that “the condyle on the ‘workingside’ moved out of the fossa away from the median linewhile the advancing condyle moved strongly inward” (p148).9 He also showed the components of the “gothicarch” or movements of the incisor point. (Reprinted fromClapp, p 149.9)

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stone in the quest for understanding mandibularmovement. It is true that his conclusions have beenfound to be largely accurate; however, his method-ology was hardly scientific. On the other hand, hedid introduce basic new information and he proba-bly never meant for his paper to be accepted formore than it was: a case study.

As far as his research methodology was con-cerned, Bennett prefaced his article by reportingthat the information he presented was “fragmen-tary and it consists mainly of an account of someexperiments that I undertook some time ago, buthave not had the time to carry out to a full extent.”2

There was only one test subject, Bennett himself,who was assisted in the experiment by his brother.Bennett described his apparatus as a facebow towhich were attached 2 very small light bulbs, 1opposite the center of the right condyle, and 1opposite the center of the sulcus of the lower lip.With the facebow in place, his head was stabilizedwith the right side of his face parallel to a wall. A

biconvex lens was placed between the light bulbsand the wall to control the magnification and tofocus the images. When the 2 light bulbs wereturned on in a dark room, the images were pro-jected on the wall. The paths of the mandibularmovements (appearing as dots of light) were thentraced by his assistant on a sheet of white paperplaced on the wall. Bennett stated that when thelateral movements were made, he was facing thewall. This is interesting because the “Bennettmovement” is described on the horizontal plane.However, to project the movement of the lightbulbs during a lateral condylar movement on a walltoward which he was facing would have displayedthe movement on the frontal (coronal) plane. Forthe image to be on the horizontal plane, it shouldhave been projected on the ceiling with the headerect.

Bennett’s report did bring to the attention of theprofession a concept that Balkwill had discoveredbut that had been buried for over 40 years. Norman

Figure 4. (A) The Gysi Con-dyle Path Register and Acces-sories. This was Gysi’s firstcommercially available model.It was adjustable and had 2reversible styli ( J and K) fortracing the condylar pathsin both the vertical and hor-izontal planes. Horseshoeplate A and incisor pointmarker E were attached towax occlusion rims formaking the tracings of the“gothic arch.” (Reprintedfrom Clapp et al, p 127.10)(B) The incisor point markermounted on a wax occlusionrim and a mandibular horse-shoe plate with a registeredincisor path. (Reprinted fromHillyer, p 999.11)

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Figure 5. (A) The Gysi “Con-dyle Register,” 1910. This viewshows the technique for trac-ing the right vertical condylarpath on a patient. Note thatthe horizontal point of the re-versible stylus is used for trac-ing on a card held in positionby an assistant. (Reprintedfrom Clapp et al, p 135.10) (B)The Gysi “Condyle Register,”1910. This frontal view of thepatient shows the techniquefor recording the lateral (Ben-nett) paths of the condyles.The vertical points of the re-versible styli are used for trac-ing on the underside of thehorizontal frosted glass platesthat the assistant holds in po-sition. (Reprinted from Clappet al, p 146.10)

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Bennett may not have explored mandibular move-ment thoroughly, but he certainly shed some lighton the subject.

Gysi: The “Gothic Arch” and“Bennett Movement”

Alfred Gysi’s contributions to the understandingof mandibular movement are considerable. How-ever, this article will focus on only the early andmore notable recording instruments that he de-

veloped during the course of his investigations.Gysi was inventive, clever, and tenacious and,through his painstaking analysis of the work ofhis predecessors, was able to develop new instru-ments and establish concepts of mandibularmovements. Although his instruments have sincebeen superceded, many of his concepts remainvalid today.

In 1910, Gysi reported on his research of theprevious 20 years in a series of articles for the DentalCosmos.3-6 He stated that, in 1901, he had “con-

Figure 6. (A) The Gysi TrubyteFacebow, 1928. This com-plete assembly consists ofthe Incisor Path Marker, at-tached to the maxillary oc-clusion rim; the gothic archregistering table, also at-tached to the mandibularocclusion rim; and the Sag-ittal Condyle Register, fas-tened to the gothic arch reg-istering table by 2 anteriorhorizontal rods. The tracingflags are still held in posi-tion by an assistant. (Re-printed with permission.12)(B) The Gysi Trubyte Face-bow and Articulator, 1928.This shows the Gysi Trubytearticulator with the facebowassembly in position withmounted casts. The rightsagittal condyle path hasbeen set and verified at 30degrees. By this time, Gysihad abandoned the lateralcondyle path registrationfor the controlling gothicarch feature of the incisalguide. (Reprinted with per-mission.12)

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Figure 7. The Snow facebow, 1924, the first instrumentused by B. B. McCollum to locate the “hinge axis.”(Reprinted from McCollum, p 529.13)

4Figure 8. (A) Early in 1927, a 3-piece adjustable face-bow had been developed. Cast metal clutches hadreplaced the unreliable modeling plastic devices. Amaxillary facebow was added to “cover up the movableskin to make the determination of the hinge axis moreprecise.” (B) This double exposure photography showsthe “mouth dropped open” technique with only rota-tion of the caliper pin. (Reprinted from McCollum, p534.13)

Figure 9. (A and B) Two views of the first instrument“to record the paths of motion of the mandible inall three dimensions at one and the same time” (1934).13

The instrument had styli to record both the vertical andlateral condylar paths. It also featured 2 anterior stylilocated in the midline: 1 vertical to record the incisorpoint and 1 horizontal to record the opening and closingmotion. (Reprinted with permission.14)

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structed a simple apparatus for measuring the slantof the condyle paths to the occlusal plane [condylarinclination].”

In the 3 photographs shown in Fig 3, ProfessorGysi demonstrates mandibular movement with anearly experimental tracing device. Figure 3A and Bshows tracings of the condylar path on the sagittalplane and those at the symphysis that occur with astraight opening and closing movement.

Gysi was not the first to determine the individualcondylar paths for articulator use, but he began toimprove and refine the process for clinical purposes.He was the first, however, to register the paths ofthe incisor point in the horizontal plane. He re-ferred to the combined anterior lateral tracings asthe “Gothic Arch.” He was also the first to measurethe lateral condylar paths (“Balkwill-Bennett”movements) and to incorporate this feature into anarticulator (Fig 3C). Gysi remarked that recordingthe movement of these points on the mandible was“the easiest part of the whole problem, but it tookseven years to make an articulator with which toimitate these movements.”3 Gysi, of course, wasreferring to the 2 adjustable articulators that pre-ceded his “Adaptable,” introduced to US dentists in1910 and patented in 1912. The “Adaptable” wasthe first articulator to include the “Balkwill-Ben-nett” movement feature.7 These 3 Gysi articulatorsappeared in the Journal of Prosthodontics March 2001article in this series.8

Figure 4A shows the various components of Gy-si’s first practical clinical version of his condylargraphic-tracing device (Gysi called it the “condyleregister”). In combination with his incisor pointmarker (Fig 4B), these instruments were capable oftracing the gothic arch as well as the condyle pathson both the vertical and horizontal planes. Themajor drawbacks in the design of the condyle reg-ister were that it was necessary for an assistant tohold the tracing surfaces (cardboard or glass) inposition and, that the vertical and horizontal con-dylar tracings could not be accomplished at thesame time (Fig 5A and B).

When Gysi introduced the Trubyte articulatorin about 1928, the notable change in the accom-panying condyle register was that the lateralcondylar path feature was no longer included (Fig6A and B). By this time, Gysi had developed theconcept of setting the controls of the articulatorby following the guiding edges of the gothic archincisal table.

A Brief Look at the Originsof Gnathology

Meanwhile, in Los Angeles, CA, Beverly B. McCol-lum, Charles E. Stuart, and Harvey Stallard weremaking history in a newly developing field of den-tistry. In 1924, the field was given a name: gnathol-ogy. Harvey Stallard, who coined the term, is gen-erally regarded as the author of the language ofgnathology.

That same year, McCollum developed the firstmethod to locate the mandibular “hinge axis.” Hisfirst attempt was with the use of an ordinary Snowfacebow. The facebow fork was modified and fas-tened to the mandibular teeth with modeling plas-tic (Fig 7). He subsequently developed a practicaladjustable mandibular hinge axis facebow with acompanion facebow-like device that was attached tothe maxillary teeth for securing the recording flagsin position under the styli (Fig 8A and B). Thedevices used for fastening the components of thehinge axis facebow to the maxillary and mandibularteeth evolved from facebow forks to cast aluminumcustom clutches.

Also in 1924, Charles E. Stuart, a young grad-uate of the University of Southern CaliforniaSchool of Dentistry, joined McCollum’s researchefforts. And with Harvey Stallard, Stuart wasthe guiding force who brought to a successfulcompletion the work that McCollum had be-gun but was unable to complete because of alengthy illness resulting from a stroke he hadsuffered in 1949.14 He died in 1968. In 1926,McCollum organized the Gnathological Society ofSouthern California. The members and associateswere dedicated to McCollum’s quest to accu-rately record and replicate mandibular move-ment, and most of these men became passion-ately involved in this new concept of gnathology.Without the generous contributions of their time,personal efforts and, of course, financial support,this ambitious project would probably not havebeen feasible.

From 1924 to 1928, 9 different models of exper-imental articulators were made before McCollumplaced into production an articulator that met hisstandards, the “Gnathoscope.”14 It would take an-other 5 years, largely because of the efforts ofStuart, to produce an instrument capable of mea-suring mandibular movement in 3 planes. In 1934,the prototype of the “Gnathograph” was demon-strated at the annual meeting of the University of

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Southern California Alumni Association (Fig 9Aand B). In 1935, the second instrument to recordmovements in 3 planes was developed (Fig 10).Besides styli to trace both the horizontal and verti-cal condylar paths, it featured 1 anterior verticalstylus for the gothic arch and 1 horizontal stylus fortracing the opening and closing movements on the

sagittal plane. In 1937, the first “satisfactory re-cording device,” the “Gnathograph,” was intro-duced (Fig 11).

From the Gnathoscope and Gnathograph,Charles Stuart would eventually develop his owngnathological system, including an articulator andpantograph for which he received a patent in 1955.

Figure 10. The second de-vice to record the movementsof the mandible in all 3dimensions, 1935. It wasdescribed as a simpler andmore universal apparatus.Note that 2 anterior horizon-tal tables have been addedand the vertical table hasbeen eliminated. (Reprintedwith permission.14)

Figure 11. The “Gnatho-graph,” “a satisfactory re-cording device,” with the“axis orbital plane indicator”in position, c.1937. It fea-tured horizontal and verticalstyli for tracing the condy-lar inclination and Bennettpaths, as well as 2 anteriorvertical styli for tracing thegothic arch lateral move-ments. The custom-mademetal clutches had metalplates attached, the lowerwith a central-bearing screw,the round end of whichrested on the upper plateduring all mandibular move-ments. (Reprinted with per-mission.14)

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References

1. Campion GG: Some graphic records of movements of themandible in the living subject and their bearing on themechanism of the joint and the construction of articulators.Dent Cosmos 1905;47:39-42

2. Bennett NG: A contribution to the study of movements ofthe mandible. J Prosthet Dent 1958;8:41-54

3. Gysi A: The problem of articulation (Part I). Dent Cosmos1910;3:1-19

4. Gysi A: The problem of articulation (Part II). Dent Cosmos1910;3:148-169

5. Gysi A: The problem of articulation (Part III). Dent Cosmos1910;3:268-283

6. Gysi A: The problem of articulation (Part IV). Dent Cosmos1910;3:403-418

7. Gysi A: Dental Articulator. US Patent No. 1,041,270. Octo-ber 15, 1912

8. Starcke EN: The history of articulators: The appearance andearly use of the incisal pin and guide. J Prosthodont 2001;10:52-60

9. Clapp GW (ed): Prosthetic Articulation. New York, NY, TheDentists’ Supply Company, 1914

10. Clapp GW, Tench RW (eds): Professional Denture Service.New York, NY, The Dentists’ Supply Company, 1918

11. Hillyer E: Development of the anatomical articulator. DentCosmos 1913;55:989-1005

12. Swenson MG (ed): Complete Dentures (ed 1). St. Louis,MO, Mosby, 1940

13. McCollum BB: Fundamentals involved in prescribing restor-ative dental remedies. Dent Items Interest 1939;61:522-535

14. McCollum BB, Stuart CE (eds): A Research Report (ed 1).South Pasadena, CA, Scientific Press, 1955

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