The History of Articulators: A Perspective on the Early Years, Part I1 Edgar N. Starcke, DDS

T MAY NEVER be known when, where, or from I whose imagination the first mechanical hinge articulator emerged. The early dcntists in America, especially thosc in the territories and on the fron- tier, often found it diricult to obtain equipment and supplies to pmctice their profession. It is likely that early hinge articulators were handmade contrivances, constructed from materials at hand. Even though well into thc 20th century plaster was commonly used to relate casts, some time before I840 mechanical hinge articulators seem to have become the preferred typc. According to the litera- ture, there were three primary reasons expressed for their use and popularity; these mechanical hinge ar- ticulators were more convenient and casicr to use, allowed modifications of the cast position when inac- curacies were suspected, and saved plaster of Paris.’

From the beginning, the term “articulator” was not popularly ascribed to the hinge-type devices. Among the more common terms were “antagonizing frames,”:! “occluding frames,” “occlusion frames,” and “antagonizors.””,~ In 19 14, Wilson3 emphatically expressed his opposition to thc widely uscd dcsigna- tion, “articulator,” artping that it was a misnomer because, in the anatomic sense, the term means “a joint.” Similarly, he considered “articulation of the teeth” incorrect because teeth can only articulate upon their proximal surfaccs and not upon their occlusal surfaces. Wilson stated that such instru- ments were intended to occlude and antagonize the teeth, not articulate them. Wilson suggested the instruments are used to arrange artificial teeth in occlusion and “they should be in ‘a~itagoIiiZalion.”’

In his textbook, Wilson referred to a simple hinge articulator as an “Occlusion Frame” and to all othcrs as “Antagonizors.” This controversy concerning terms

was quite evident in the literature for years, but with the passnge oT time, “articulation” and “artic~lator” have become the accepted tcrms. In the Glossary of Yrosthodontic Terms (seventh edition): “articula- tion” is defined as, “in dentistry, the static and dynamic contact relationship between the occlusal surfaces of the teeth during function.” The tcrm “articulator” is defined as “a mechanical instrument that represents the temporomandibular joints and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements.” In contrast, the Glossary describes- “occluding frame” as an obsolcte term, while omit- ting the terms, “antagonizing frame” and “antagoni- zors” altogether.

Early References to Mechanical Hinge Articulators

The first published reference to the earliest mechani- cal hinge articulators is probably Fairhurst’s6 discus- sion of Hovarth‘s articulator and Ladmore’s articula- tor of the 1830s. Fairhurst describcd these and other early examplcs as instruments consisting of two wooden or metal blocks or slabs hinged together with a simple hinge. These articulators and others of the day must certainly have resembled what is now commonly referred to as the ”barn door hinge” (Fig l).*

Correspondence to: Edgar AV Starcke, DDS, Clinical P r n j r . , Deport- ment uf Pmsthodontics, The Lrniimity of Te,zas Houston Health S c i e n r - Center Dental Branch, 6516 John Freeman Arienue, P.O. Box 20068, Houston, TX 77225, E-mail: ~s tarcke~mai l .~ .u th . tmc .~di~

Copjri@t 8 1999 ly The American Collepe ofPrmthodontists I0jY-Y4IX/99/0804-0011$5.00/0

Journal qjProsthodontics, Vobl8, No 4 [December), 1999:bp 277-280 277

A R T I C U L A T O R S .

INVENTED BY W. H. SMITE, NEWPORT, R. I. Thia article is made of brass, and possesses the advantage over those fn general

use in having n screw m d hinge, whereby it can he adjusted to any angle. There is slso a set ecreew, allowing the top to slide either backward mforaard. It ha8 met with general favor by tlrose who have used it. Price $1.00.

SAMUEL 8. WHITE.

Figure 1. A “Barn Door Hinge” Articulator in the collec- tion of the University of Texas-Houston Dental Branch.

Illustrations of mechanical hinge articulators found most commonly in the early literature wcre thosc that were commercially manufactured and pro- moted. Because scientific articles on articulators were rare at that time, dentists were highly depen- dent an advertisements that provided illustrations

About 40 hinge-type articulators were patented between 1860 and 1910. However, numerous commer- cially successful articulators were not patented (Fig 3).

One of the earliest mechanical hinge articulators illustrated and discussed in some detail in the litera- ture is attributed to Thomas W. Evans.? In his textbook, Chapin A. Harris (fourth edition, 1X50)7 described the T. Mi. Evans articulator as a “very simple instrument by means of which the extension of the plaster back of the plates and wax is rendcrcd unnecessary.” He ernphasizcd that the most impor-

(Fig 2).

Figure 2. This is an S. S. Whitr ad for an articulator attributed to W. H. Smith. This articulator likely first appeared in the 18f2 Samuel S. White catalogue, the first catalogue produced by White after the dissolution of the partnership ofJones and White in 1861. The S. S. White Dental Manufacturing Co, incorporated in 1881, has col- laborated with several inventors associated with articula- tors, notably W. G. A. Bonwd and Rupert Hall. (Reprinted from McQuillan JH, Zieglar GJ (eds): Dental Cosmos, Philadelphia, PA, Samuel S. White, August 1865, vol7.)

tant feature was that vertical dimension could be preserved or altered as required.’

Harris was initially introduccd to this devicc in 1849 when Evans sent a sample of one to the edtors

THE WILMINGTON DEXTAL MANUFACTURING CO

STANDARD ARTICULATO R.

The capacity of this Articulator is all that is necessary. It will take single or double models, and admit of any change in articula- tion. Entirely of brass, nicely fitted,finely pol- ished, nickel-plated.

PRICES. As above. ........ $1.25 Pla,in Brass ...... .85

Figure 3. A v e n popular articulator or common basic design. Note the uncommon feature: a vertical rod at- tached to thr wing-nut to support thc fully opened upper member. (Reprinted from the 1890 Wilmingon Dental Manufacturing Co catalogue, Philadclphia, PA, p 293.)

Figure 4. Thomas W. Evans hrticulator. Woodcut snbmit- ted by J. r). Chevalirr to the American Juurnal Ilenlal Science. Vertical rod D and wing-nut E control vertical dimension. This is artually the second appearance of the ‘tertical stop” feature. Daniel T. Fxens recorded the first in his patent application (1840). (Reprinted from Cheva- lier?)

of TheAmerican Journal ofDeenta1 Scietice for eva1uaLion.t As a co-editor, Harris reported receiving Evans’ “antagonizing instrument for artificial tccth” and noted that, “With the exception of a plaster antago- nizing model, it is superior to any we have seen.”H In April 1850, John D. Chevalier of New York submit- ted, with a letter to the editor, a woodcut of the Evans instrument and a description of its use. Chevalier intended to manufacture it and commissioned the woodcut for his circularsg (Fig 4).

It is not known if Thomas Evans patented his articulator, and this illustrates one of the obstacles encountered by investigators seeking early patent data: according to the records of the US patcnt office before 1870 may be incomplctc. In that year, the Commissioner of Patents completely reorga- nized the system of kecping records and issuing patcnt letters. Furthermore, sometimc between 1840, when the first patents were issued, and 1870, a fire destroyed many of the original patent records. Accord- ing to the existing records, only four articulator

patcnts were issued between 1840 and 1870. It is logical to assume that because of the number of‘ patents issued during the subsequcnt three decades (about 45), some records werc lost.

The First US Articulator Patent The first US patent for ari articulator was issued to James Cameron on April 30, 1840 (Fig 6A and B). Cameron’s articulator was unique in its departure in design from othcr hinge-type devices, and it is not clcar why he chosc such a design. However, the inclusion ofthe anterior-posterior and vertical adjust- ment features does show his concern for the pcrva- sive problems related to the wax impression and “mush-bite” techniques of the day and the necessity to makc corrections using articulators. Cameron’s articulator also displayed a mistaken concept that has been, with some persistence, repeated in articula- tor design-that is, the idea that the ma.ndibular member of the articulator must move. The second

Figure 5. Thomas W. Evans (1823-1897). (Reprinted from Rainey.! I )

Figure 6 . 64) From Patent #1,574, April 1840. This was essentially a plasterless hingc-type device. Kod E allows an anterior-posterior adjustment of upper plate A. Assembly K incorporates a vertical adjustment and the hinge mechanism for the lowcr plate B. Rods M and 0 are supports for the lowcr platc B. (B) This is an actual model of the Cameron articulator. (Reprinted from House.'")

articulator to be patented, that of Daniel T. Evens, exemplifies this problem, but also represents an advancement in the understanding of mandibiilar movement (more of the history of articulators in thc next issue of the Journal ofProsthodontiw).

References 1. Harris CA (ed): The Principles and Practice of Dental Surgery

(ed 8). Philadelphia, P& Lindsay & Blakiston, 1863, p 685 2. kchardson J (ed): A Practical Treatise on Mechanical Drn-

tistry (ed 1). Philadelphia, PA, Lindsay & Blakiston, 1860, p

3. Wilson GH (ed): A Manual of Dcntal Prosthetics (ed 2).

4. Waugh Lhl: The laws of antagoniaation of the teeth in

2 75

Philadelphia, PA, Lea &E'ebiger, 1914, pp 159-160

orthodontia. Dent Items oflnterest 1910;32:192-213

5. The glossary of prosthodontic terms (ed 7). J Prosthet Dcnt 1999;81:48

6. Fairhurst R: The Wadsworth Articulator. Dent Rec 1929;49: 58-66

7. Harris CA (ed): The Principles and Prarticc of Dental Surgery (cd 4). Philadelphia, PA, Lindsay & Blakiston, 1850, pp 699-700

8. Harris CA: Editor's note: &I antagonizing instrument for artificial teeth. Am J Dent Sci 1819;1054

9. Chevalier JD: Evans'htagonizing Instrument. Am JDent Sci 1850; 10206-208

10. House JE: The des ip and use of dental articulators in the United States from 1840-1970. Masters thesis, IndiamUniver- sity School of Dentistry, Indianapolis, IN, 1970

11. Rainey H (ed): Dr. Thomas W'. Evans, America's Dentist to European Royalty. Philadelphia, PA, Thc Evons Co, 1916, pp 9-19