- Email: [email protected]
Centric relation records—Historical review
Centric relation records-Historical
review
Michael L. Myers, D.M.D. * Medical
University
of South Carolina,
College
of Dental
M
any prosthodontists feel that recording centric relation is the most difficult, yet the most important, step in treating edentulous patients with complete dentures.‘-3 However, a review of dental literature reveals that the philosophies and methods vary greatly on how to make the actual registration. Centric relation is generally defined as “the most retruded relation of the mandible to the maxillae when the condyles are in their most posterior unstrained positions in the glenoid fossa from which lateral movements can be made, at any given degree of jaw separation.“’ This definition is open to various interpretations, and many prosthodontists disagree with it in part or entirely. It is generally agreed that centric relation records can be grouped into four categories-direct checkbite (interocclusal) tecordings, graphic recordings (intraoral and extraoral), functional recordings,’ and cephalometrics.
DIRECT CHECKBITE RECORDINGS
INTEROCCLUSAL
The direct interocclusal record is the oldest type of centric relation record. In 1756, Phillip Pfaff, the dentist of Frederick the Great of Germany, was the first to describe this technique of “taking a bite.“’ Until the end of the nineteenth century it was the most commonly used method.‘ The direct interocclusal record during that period, was a nonprecision ,jaw record obtained by placing a thermoplastic material, usually wax or compound, between the edentulous ridges and having the patient close into the material. This was known as the “mush,” “biswas cuit,” or “squash” bite.’ In 1905, Christensen” one of the early authors to use “impression wax” for “bite” records. In 1910, Greene’ described a mushbite made from modeling compound in which he used a plaster wash to achieve a more accurate record. Occlusion rims were later added to the technique to provide a more stable base.
*.i\ssociate Professor, Crown and Bridge Dentistry.
Medicine,
Charleston,
S.C
One early method was to adjust the occlusion rims to the chosen vertical dimension of occlusion, have the patient close in a retruded position, and attach the rims together for mounting on an articulator. This was usually done with staples or by sealing the rims with a hot instrument.!‘. I0 Another practice was to soften one of the occlusion rims and have the patient close to a vertical dimension determined by the dentist.; In 1954, Brown “’ recommended repeated closures into softened wax rims. Greene; had his patients hold their jaws apart for IO seconds to fatigue the muscles and then had them snap the rims together. He then made lines in the rims to orient them after removal from the mouth. Gradually, these procedures evolved into interocclusal records as they are usually done today. Small amounts of wax, compound, plaster. or zinc oxide-eugenol paste were placed between the occluding rims, and the patient closed the jaws into centric relation. These improvements were an attempt to equalize the pressure of vertical contact. Some methods relied on removing the posterior portions of the mandibular occlusion rim. Then the anterior segment would maintain the vertical dimension of occlusion as the patient closed into a softened material which was on the posterior portion.” Other methods incorporated closure of cones, pyramids, or ridges of wax into grooves which had been cut in the maxillarv rims.“-” the best mateThere are many opinions regarding rial for interocclusal record. Trapozzano” stated that the wax “checkbite method is the technique of preference in recording and checking centric relation.” Schuyler” observed that if the recording medium was not of uniform density and viscosity, uneven pressures would be transmitted to the record bases which would cause a disharmony of occlusion. He said that modeling compound was preferable to wax for occlusal records because it can be softened more evenly, cools slower, and doesn’t distort as much as wax. Payne’” and Hickey”* stated a preference for plaster because less material had to be
THE JOURNAL
OF PROSTHEJ’JC
DENTISTRY
141
MYERS
placed in the patient’s mouth for the record. BOOS” wrote that it was important to avoid torsion when recording centric relation. Wax or compound, which required the application of force, could displace the mandible. Therefore, Boos thought a material such as plaster or zinc oxide-eugenol paste was more accurate. to be HanaulP was one of the first individuals concerned about equalization of pressure when recording the bite. He wrote, “I attribute the total of the causative factor of denture mobility and consequent change of positional relation to the resilient and like effect of saliva, tissues, restorations, gluey adhesives, and possibly of films of food interposed between the masticatory surfaces during function.” He coined the word “Realeff,” which is formed by the beginning letters of the words “resilient and like effect.” This consideration of the resiliency of the oral tissues became a major factor in “checkbite” techniques. Wright I1 described the four factors he believed affected the accuracy of records: resiliency of tissue, saliva film, fit of bases, and pressure applied. He concluded that the dentist couldn’t control the pressure at which the record was made, so the best technique was to record the occlusal record at zero pressure. It could thus be duplicated. Hanua,‘” Block,20 and other? agreed with the zero pressure philosophy. Schuyler,‘* Payne,‘” and Trathe use of pozzano,lg among othersZ’-‘” advocated light pressure. The problem of pressure in any record was recognized by BoucherZ4 who wrote, “In addition to technical errors are the errors which occur as a result of failure to control jaw activities and pressure at the time of registration.” In 1910, Greene? invented his “Pressometer” in an early attempt to equalize the pressure of recording centric relation. It consisted of two celluloid strips placed between the maxillary and mandibular occlusion rims on the right and left sides. If the pressures were unequal, the rims would “hold” one strip while the other could be removed. The techniques for “getting the jaw back” were as varied as the types of materials. Most prosthodontists had the patients close, unassisted, into a retruded mandibular position. This was combined with having the patient swallow, touch his tongue to the soft palate, make rapid jaw movements to tire muscles, and other techniques, in an attempt to achieve the retruded position of the mandible.25 Many authors advocated some degree of control over the jaw movement. This was generally light pressure on the chin or guiding of the mandible.“-13. *6
142
The importance of verifying the interocclusal records has been stressed by many authors.?. ‘*. ” Schuyler” stated that he did not “consider a record secured on compound or wax occluding rims sufficiently free from error to complete the restorations without additional checks.” There have been many criticisms of “checkbites” for centric relation records. Most of these criticisms were from individuals who favored some type of graphic recording. Simpson28 felt that wax records were unscientific. PhillipszY stated that “in the hands of by far the largest majority of operators, it is worse than useless.” Gysi ‘3o tested this method on manikins and never got the same recording twice with wax or compound. He concluded that the uneven cooling of the material produced distortion. The only accurate material he found for interocclusal records was plaster. Page3’ said that centric records were “worthless the instant the apposition or the surfaces are altered.”
GRAPHIC RECORDINGS The earliest graphic recordings were based on studies of mandibular movements by Balkwi1P2 in 1866. The intersection of the arcs produced by the right and left condyles formed the apex of what is known as the Gothic arch tracing.3’ The first known “needle point tracing” was by Hesse in 1897, and the technique was improved and popularized by Gysi around 1910.“3 The tracer made by Gysi was an extraoral incisal tracer. The tracing plate, coated with wax, was attached to the mandibular rim. A spring-loaded pin or marker was mounted on the maxillary rim. The rims were made of modeling compound to maintain the vertical dimension of occlusion. When a good tracing was recorded, the patient held the rims in the apex of the tracing while notches were scored in the rims for orientation. 34 Clapp35 described the use of a Gysi tracer which was attached directly to the impression trays. Sears”@ used lubricated rims for easier movement. He placed the needle point tracer on the mandibular rim and the plate on the maxillary rim. He believed this made the angle of the tracing more acute and more easily discernible. He would then cement the rims together for removal. PhillipF recognized that any lateral movements of the jaw would cause interference of the rims which could result in a distorted record.’ He developed a plate for the upper rim and a tripoded ballbearing mounted on a jackscrew for the lower rim. The occlusion rims were removed, and when the patient
FEBRUARY
1982
VOLUME
47
NUMBER
2
CENTRIC
RELATION
RECORDS
had produced the proper extraoral tracing, softened compound was inserted between the trial bases. This innovation was named the “central bearing point,” which supposedly produced equalization of pressure on the edentulous ridges. In 1929, Stansbe@’ introduced a technique which incorporated a curved plate with a 4-inch radius (corresponding to Monson’s curve) mounted on the upper rim. A central bearing screw was attached to a lower plate with a 3-inch radius curve (reverse-Monson curve). After the extraoral tracing was made, plaster was injected between the plates to form a biconcave centric registration. HallZh (1929) used Stanbery’s method but substituted compound for the centric relation record. Later graphic recording methods used the central bearing point to produce the Gothic arch tracing. Hardy”!’ and Pleasure”’ described the use of the Coble Balancer, and Hardy later designed a modified intraoral tracer similar to the Coble. Hardy:l” and Porter” made a depression with a round bur at the apex of the tracing. The patient would hold the bearing point in the depression while plaster was injected for the centric record. Pleasure’” used a plastic disk which was attached to the tracing plate with a hole over the apex of the Gothic arch. The centric relation record could then be made without a change of vertical dimension.” Various tracing devices were designed by Hight, Phillips, Terrell, Sears, House, Messerman, and others.‘“, -)?The Sears’ Recording Trivet had an intraoral central bearing point and two extraoral tracing plates. The maxillary and mandibular tracing arms were locked into c&tric relation with two lumps of plaster. Robinson”:’ designed the Equilibrator, a tracing device with a hydraulic system and four bearing pistons, one each in the bicuspid and molar region. It produced a functional record of centric relation with a uniform distribution of stress over the basal seat. used an intraoral Gothic arch tracer Sliverman” to locate the “biting point” of a patient. The patient was told to bite hard on the tracing plate. This developed the functional resultant of the closing muscles which would retrude the mandible. The indentation made by the patient would be used for the centric record whether or not it corresponded to the Gothic arch apex. The graphic recording, like the “checkbite In records,” received much praise and criticism. “The most naive of our 1923, Hanau’” wrote, geniuses had intuitions, molded into metal, attached a decorative theory onto their accomplishment and,
THE JOURNAL
OF PROSTHETIC
DENTISTRY
it must be admitted, they found a goodly number of fanatical believers and blind followers, whose mental inertia probably did not care to penetrate even the polish of the nickel-plated instrument under consideration.” In 1927, Hanauls conceded that the Gysi tracing was satisfactory to check records, but that universal usage was not good. On the other hand, Tenth’” stated that the Gysi tracing technique was the only means that should be used for centric records; all other methods were “mere deceptions and playthings.” Gysi:‘” concluded that his tracing technique had only a 5-degree error. whereas wax and compound bites had a 25-degree error. Criticisms of Gothic arch tracings stated that equalization of pressures did not occur, prognathic or retrognathic patients could not be used, and flabby tissues or large tongues could cause shifting of bases.‘ Payne” stated that the tracing was difficult to see and too much patient cooperation was needed. Trapozzano ‘-I believed that “checkbites” were far more accurate than the central bearing point could possibly be, due to the unequal pressure produced. Block”’ made the point that any sore spot under the baseplate could cause an eccentric tracing. Grange?: stated that the Gothic arch produced was generally rounded and was not precise enough. FUNCTIONAL
RECORDINGS
Functional records were described in dental literature as early as 1910. Greene’ used a pumice and plaster mixture in one of the rims and instructed the patient to grind the rims together. The denture teeth were set to the generated paths. Needles-l” mounted three studs on maxillary rims which cut arrow tracings into mandibular compound rims. .4fter removal from the mouth, the rims were reassembled with the functinal grooves. Patterson”’ cut a trough in the upper and lower rims. These were filled with a Carborundum and plaster mixture. The patient would move his jaw and grind the rims until the proper curvature had been established. This would ensure equalized pressure and uniform tooth contact in all excursions. The functional technique developed by Meyer”” used soft wax occlusion rims. Tinfoil was placed over the wax and lubricated. The patient performed the functional movements to produce a wax path. A plaster index was made of the wax path and the teeth were set to the plaster index. BOOS” used the Gnathodynamometer to determine the vertical and horizontal position at which a maximum biting force could tx produced. His
143
MYERS
Bimeter was mounted on the lower occlusion rim with a central bearing point against a plate on the upper occlusion rim. Plaster registrations were made with the Bimeter in the mouth and the patient exerting pressure. Boos theorized that optimum occlusal position and the position of maximum biting force would coincide. He also thought that it was essential that all registrations be made under biting force so that the displacement of soft tissues which occur in function, would occur during bite registration.j*, 53 Shanahan,j4 in his physiologic technique, placed cones of soft wax on the mandibular rim and had the patient swallow several times. During swallowing, the tongue forced the mandible into its centric relation position. The cones of soft wax were moved and the physiologic centric relation was recorded. CEPHALOMETRICS The use of cephalometrics to record centric relation was described by Pyott and Schaeffer.55 The proper centric relation and vertical dimension of occlusion were determined by cephalometric radiographs. This method, however, was somewhat impractical and never gained widespread usage. It is apparent from the dental literature, that there are many opinions and much confusion concerning centric relation records. One would have to agree with Sear9 who wrote 3 “The problem has confused a great number of readers, which is not surprising, as many of the writers are also confused.” BOOSTS probably came closest to the solution when he stated that “in normal cases, the .occlusion, the temporomandibular joints, the bone, the soft tissue, and the musculature all produce the same relation to each other and any one of the many registration techniques may be used.” A certain technique might be required for an unusual situation or a problem patient. In the final analysis, the skill of the dentist and the cooperation of the patient are probably the most important factors in securing an accurate centric relation record. REFERENCES 1. Swenson, M. G.: Complete Dentures, ed 6. St. Louis, 1970, The C. V. Mosby Co. 2. Nagle, R. J., and Sears, V. H.: Denture Prosthetics, ed 2. St. Louis, 1962, The C. V. Mosby Co. 3. Gehl, D. H., and Dresen, 0. M.: Complete Denture Prosthesis, ed 4. Philadelphia, 1948, W. B. Saunders Co. 4. Academy of Denture Prosthetics: Glossary of prosthodontic terms, ed 2. J PROSTHETDENT 6:13, 1960. 5. Kingery, R. H.: Problems associated with centric relation. J PROSTHET DENT 2:307, 1952.
144
6.
7. 8. 9. 10. 11.
12. 13. 14. 15. 16. 17. 18.
19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35.
Schlosser, R. 0.: Methods of securing centric relation and other positional relation records in complete denture prosthesis. J Am Dent Assoc 28:17, 1941. Greene, J. W.: Greene Brothers’ Clinical Course in Dental Prosthesis, 1910. Christensen, C.: The problem of the bite. Dent Cosmos 47:1184, 1905. Prothero, J. H.: Prosthetic Dentistry. Chicago, 1921, Medical-Dental Publishing Co. Brown, J. C.: Articular mechanisms for inducing condyle migration. J PROSTHET DENT 4:208, 1954. Wright, W. H.: Use of intraoral jaw relation wax records in complete denture prosthesis. J Am Dent Assoc 26~542, 1939. Schuyler, C.: Intraoral method of establishing maxillomandibular relation. J Am Dent Assoc 19:1012, 1932. Brill, N.: Reflexes, registrations, and prosthetic therapy. J PROSTHET DENT 7:341, 1957. Trapozzano, V. R.: Occlusal records. J PROSTHET Dwr 5~325, 1955. Payne, S. H.: Selective occlusion. J PROSTHET DENT 5:302, 1955. Hickey, J. C.: Centric relation-A must for complete dentures. Dent Clin North Am, November, 1964. Boos, R. H.: Centric relation and functional areas. J PROSTHET DENT 9: 191, 1959. Hanau, R. L.: Why Is Centric Relation Once Established Not Retained Subsequently? Unpublished Paper, Northwestern University Dental School Library, 1929. Hanau, R. L.: Dental Engineering, vol I, part II. Buffalo, 1927, Hanau Engineering Co. Block, L. S.: Common factors in complete denture prosthetics. J PROSTHETDENT 3:736, 1953. Jamieson, C. H.: A modern concept of complete dentures. J PRO~THET DENT 6~582, 1956. Trapozzano, V. R.: An analysis of current concepts of occlusion. J PRO~THETDENT 5:764, 1955. Kazis, H.: Functional aspects of complete mouth rehabilitation. J PROSTHETDENT 2:575, 1952. Boucher, C. 0.: Current status of prosthodontics. J PROSTHET DENT 10:421, 1960. Yasaki, M.: The height of the occlusion rim and the interocclusal distance. J PROSTHETDENT 11:26, 1961. Lucia, V. 0.: Modern Gnathological Concepts. St. Louis, 1961, The C. V. Mosby Co. Beck, H.: Selection of an articulator and jaw registration. J PRO~THET DENT 10:884, 1960. Simpson, H.: Registration of centric relation in complete denture prosthesis. J Am Dent Assoc 26:1682, 1939. Phillips, G. B.: Fundamentals in the mandibular movements in edentulous mouths. J Am Dent Assoc 14:409, 1927. Gysi, A.: Practical application of research results in denture construction. J Am Dent Assoc 16:199, 1929. Page, H. L.: Maxillomandibular terminal relationships. Dent Dig 57:490, 1951. Balkwill, F. H.: The best form and arrangement of artificial teeth for mastication. Br J Dent Sci 9:278, 1866. Sears, V. H.: Centric jaw relation. Dent Dig 58:302, 1952. Gysi, A.: The problem of articulation. Dent Cosmos 52:1, 1910. Clapp, G. W.: Prosthetic Articulation. New York, 1914, The Dentists Supply Co.
FEBRUARY
1982
VOLUME
47
NUMBER
2
CENTRK
RELATION
RECORDS
36.
Sears, V. H.: Jaw relations and a means of recording the most important articulator adjustment. Dent Cosmos 68:1047. 1926. 37. Stansbery. C. J.: Functional position checkbite technique. J Am Dent Assoc 16:421, 1929. 38. Hall, R. E.: Full denture construction. J Am Dent Assoc 16:1157, 1929. 39. Hardy, I. R.: Technique for use of nonanatomic acrylic posterior teeth. Dent Dig 48:562, 1942. 40 Pleasure, M. A.: Occlusion of cuspless teeth for balance and comfort. J PROSTHET DENT 5:305, 1955. 41. Porter, C. G.: The cuspless centralized occlusal pattern. J PROSTHET DENT 5:313, 1955. 42 Kapur, K. K., and Yurkstas, A. A.: An evaluation of centric relation records obtained by various techniques. J PROWHET DENT 7:770,
43
1957.
Robinson, S. C.: Equilibrated THET DENT 2462,
44
45. 46
functional
occlusion. J PROS-
1952.
Silverman, M. M.: Centric occlusion and jaw relations and fallacies of current concepts. J PROSTHET DENT 7~750, 1957. Hanau, R.: The relation between mechanical and anatomical articulation. J Am Dent Assoc 10:776, 1923. Tenth, R. W.: Interpretation and registration of mandibulomaxillary relations and their reproduction in an instrument. J Am Dent Assoc 13:1675, 1926.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
&anger, E.: Centric relation. J PROSI.IIET DENT 2:160, 1952. 48. Needles, J. W.: Practical uses of curve of Spee. J Am Dent Assoc l&918, 1923. 49. Patterson, A. H.: ConstructIon of artificial dentures. Dent Cosmos 65:679, 1923. 50. Meyer, F. S.: A new, simple and accurate technique for obtaining balanced and functional ncclwion J .4m Dent Assoc 21:195, 1934. relation established by biting 51. Boos, R. H.: Intermaxillary power. J Am Dent Assoc 27:1192, 1940. 52. Boos, R. H.: Occlusion from rest position. ,I PRCXTHET DENT 2:575, 1952. 53. Boos, R. H.: Basic anatomic factors of jaw position. J PROSTHET DENT 4:200, 1954. 54. Shanahan, T. E.: Physiologic jaw relations and occlusion of complete dentures. J PROSTHET DENT 5:319, 1955. 55. Pyott, J. E., and Schaeffer. A.: Simullaneous recording of centric occlusion and vertical dimension. .f Am Dent Asoc 44:430, 1952 Reprint requeststo: 47.
DR. MICHAEL L. MYERS MEDICAL UNIVERSITY DF SOUTH CAROLINA COLLEGE OF DENTAL MEDICINE 171 ASHLEY AVE. CHARLESTON, SC: 29425
145
review
Michael L. Myers, D.M.D. * Medical
University
of South Carolina,
College
of Dental
M
any prosthodontists feel that recording centric relation is the most difficult, yet the most important, step in treating edentulous patients with complete dentures.‘-3 However, a review of dental literature reveals that the philosophies and methods vary greatly on how to make the actual registration. Centric relation is generally defined as “the most retruded relation of the mandible to the maxillae when the condyles are in their most posterior unstrained positions in the glenoid fossa from which lateral movements can be made, at any given degree of jaw separation.“’ This definition is open to various interpretations, and many prosthodontists disagree with it in part or entirely. It is generally agreed that centric relation records can be grouped into four categories-direct checkbite (interocclusal) tecordings, graphic recordings (intraoral and extraoral), functional recordings,’ and cephalometrics.
DIRECT CHECKBITE RECORDINGS
INTEROCCLUSAL
The direct interocclusal record is the oldest type of centric relation record. In 1756, Phillip Pfaff, the dentist of Frederick the Great of Germany, was the first to describe this technique of “taking a bite.“’ Until the end of the nineteenth century it was the most commonly used method.‘ The direct interocclusal record during that period, was a nonprecision ,jaw record obtained by placing a thermoplastic material, usually wax or compound, between the edentulous ridges and having the patient close into the material. This was known as the “mush,” “biswas cuit,” or “squash” bite.’ In 1905, Christensen” one of the early authors to use “impression wax” for “bite” records. In 1910, Greene’ described a mushbite made from modeling compound in which he used a plaster wash to achieve a more accurate record. Occlusion rims were later added to the technique to provide a more stable base.
*.i\ssociate Professor, Crown and Bridge Dentistry.
Medicine,
Charleston,
S.C
One early method was to adjust the occlusion rims to the chosen vertical dimension of occlusion, have the patient close in a retruded position, and attach the rims together for mounting on an articulator. This was usually done with staples or by sealing the rims with a hot instrument.!‘. I0 Another practice was to soften one of the occlusion rims and have the patient close to a vertical dimension determined by the dentist.; In 1954, Brown “’ recommended repeated closures into softened wax rims. Greene; had his patients hold their jaws apart for IO seconds to fatigue the muscles and then had them snap the rims together. He then made lines in the rims to orient them after removal from the mouth. Gradually, these procedures evolved into interocclusal records as they are usually done today. Small amounts of wax, compound, plaster. or zinc oxide-eugenol paste were placed between the occluding rims, and the patient closed the jaws into centric relation. These improvements were an attempt to equalize the pressure of vertical contact. Some methods relied on removing the posterior portions of the mandibular occlusion rim. Then the anterior segment would maintain the vertical dimension of occlusion as the patient closed into a softened material which was on the posterior portion.” Other methods incorporated closure of cones, pyramids, or ridges of wax into grooves which had been cut in the maxillarv rims.“-” the best mateThere are many opinions regarding rial for interocclusal record. Trapozzano” stated that the wax “checkbite method is the technique of preference in recording and checking centric relation.” Schuyler” observed that if the recording medium was not of uniform density and viscosity, uneven pressures would be transmitted to the record bases which would cause a disharmony of occlusion. He said that modeling compound was preferable to wax for occlusal records because it can be softened more evenly, cools slower, and doesn’t distort as much as wax. Payne’” and Hickey”* stated a preference for plaster because less material had to be
THE JOURNAL
OF PROSTHEJ’JC
DENTISTRY
141
MYERS
placed in the patient’s mouth for the record. BOOS” wrote that it was important to avoid torsion when recording centric relation. Wax or compound, which required the application of force, could displace the mandible. Therefore, Boos thought a material such as plaster or zinc oxide-eugenol paste was more accurate. to be HanaulP was one of the first individuals concerned about equalization of pressure when recording the bite. He wrote, “I attribute the total of the causative factor of denture mobility and consequent change of positional relation to the resilient and like effect of saliva, tissues, restorations, gluey adhesives, and possibly of films of food interposed between the masticatory surfaces during function.” He coined the word “Realeff,” which is formed by the beginning letters of the words “resilient and like effect.” This consideration of the resiliency of the oral tissues became a major factor in “checkbite” techniques. Wright I1 described the four factors he believed affected the accuracy of records: resiliency of tissue, saliva film, fit of bases, and pressure applied. He concluded that the dentist couldn’t control the pressure at which the record was made, so the best technique was to record the occlusal record at zero pressure. It could thus be duplicated. Hanua,‘” Block,20 and other? agreed with the zero pressure philosophy. Schuyler,‘* Payne,‘” and Trathe use of pozzano,lg among othersZ’-‘” advocated light pressure. The problem of pressure in any record was recognized by BoucherZ4 who wrote, “In addition to technical errors are the errors which occur as a result of failure to control jaw activities and pressure at the time of registration.” In 1910, Greene? invented his “Pressometer” in an early attempt to equalize the pressure of recording centric relation. It consisted of two celluloid strips placed between the maxillary and mandibular occlusion rims on the right and left sides. If the pressures were unequal, the rims would “hold” one strip while the other could be removed. The techniques for “getting the jaw back” were as varied as the types of materials. Most prosthodontists had the patients close, unassisted, into a retruded mandibular position. This was combined with having the patient swallow, touch his tongue to the soft palate, make rapid jaw movements to tire muscles, and other techniques, in an attempt to achieve the retruded position of the mandible.25 Many authors advocated some degree of control over the jaw movement. This was generally light pressure on the chin or guiding of the mandible.“-13. *6
142
The importance of verifying the interocclusal records has been stressed by many authors.?. ‘*. ” Schuyler” stated that he did not “consider a record secured on compound or wax occluding rims sufficiently free from error to complete the restorations without additional checks.” There have been many criticisms of “checkbites” for centric relation records. Most of these criticisms were from individuals who favored some type of graphic recording. Simpson28 felt that wax records were unscientific. PhillipszY stated that “in the hands of by far the largest majority of operators, it is worse than useless.” Gysi ‘3o tested this method on manikins and never got the same recording twice with wax or compound. He concluded that the uneven cooling of the material produced distortion. The only accurate material he found for interocclusal records was plaster. Page3’ said that centric records were “worthless the instant the apposition or the surfaces are altered.”
GRAPHIC RECORDINGS The earliest graphic recordings were based on studies of mandibular movements by Balkwi1P2 in 1866. The intersection of the arcs produced by the right and left condyles formed the apex of what is known as the Gothic arch tracing.3’ The first known “needle point tracing” was by Hesse in 1897, and the technique was improved and popularized by Gysi around 1910.“3 The tracer made by Gysi was an extraoral incisal tracer. The tracing plate, coated with wax, was attached to the mandibular rim. A spring-loaded pin or marker was mounted on the maxillary rim. The rims were made of modeling compound to maintain the vertical dimension of occlusion. When a good tracing was recorded, the patient held the rims in the apex of the tracing while notches were scored in the rims for orientation. 34 Clapp35 described the use of a Gysi tracer which was attached directly to the impression trays. Sears”@ used lubricated rims for easier movement. He placed the needle point tracer on the mandibular rim and the plate on the maxillary rim. He believed this made the angle of the tracing more acute and more easily discernible. He would then cement the rims together for removal. PhillipF recognized that any lateral movements of the jaw would cause interference of the rims which could result in a distorted record.’ He developed a plate for the upper rim and a tripoded ballbearing mounted on a jackscrew for the lower rim. The occlusion rims were removed, and when the patient
FEBRUARY
1982
VOLUME
47
NUMBER
2
CENTRIC
RELATION
RECORDS
had produced the proper extraoral tracing, softened compound was inserted between the trial bases. This innovation was named the “central bearing point,” which supposedly produced equalization of pressure on the edentulous ridges. In 1929, Stansbe@’ introduced a technique which incorporated a curved plate with a 4-inch radius (corresponding to Monson’s curve) mounted on the upper rim. A central bearing screw was attached to a lower plate with a 3-inch radius curve (reverse-Monson curve). After the extraoral tracing was made, plaster was injected between the plates to form a biconcave centric registration. HallZh (1929) used Stanbery’s method but substituted compound for the centric relation record. Later graphic recording methods used the central bearing point to produce the Gothic arch tracing. Hardy”!’ and Pleasure”’ described the use of the Coble Balancer, and Hardy later designed a modified intraoral tracer similar to the Coble. Hardy:l” and Porter” made a depression with a round bur at the apex of the tracing. The patient would hold the bearing point in the depression while plaster was injected for the centric record. Pleasure’” used a plastic disk which was attached to the tracing plate with a hole over the apex of the Gothic arch. The centric relation record could then be made without a change of vertical dimension.” Various tracing devices were designed by Hight, Phillips, Terrell, Sears, House, Messerman, and others.‘“, -)?The Sears’ Recording Trivet had an intraoral central bearing point and two extraoral tracing plates. The maxillary and mandibular tracing arms were locked into c&tric relation with two lumps of plaster. Robinson”:’ designed the Equilibrator, a tracing device with a hydraulic system and four bearing pistons, one each in the bicuspid and molar region. It produced a functional record of centric relation with a uniform distribution of stress over the basal seat. used an intraoral Gothic arch tracer Sliverman” to locate the “biting point” of a patient. The patient was told to bite hard on the tracing plate. This developed the functional resultant of the closing muscles which would retrude the mandible. The indentation made by the patient would be used for the centric record whether or not it corresponded to the Gothic arch apex. The graphic recording, like the “checkbite In records,” received much praise and criticism. “The most naive of our 1923, Hanau’” wrote, geniuses had intuitions, molded into metal, attached a decorative theory onto their accomplishment and,
THE JOURNAL
OF PROSTHETIC
DENTISTRY
it must be admitted, they found a goodly number of fanatical believers and blind followers, whose mental inertia probably did not care to penetrate even the polish of the nickel-plated instrument under consideration.” In 1927, Hanauls conceded that the Gysi tracing was satisfactory to check records, but that universal usage was not good. On the other hand, Tenth’” stated that the Gysi tracing technique was the only means that should be used for centric records; all other methods were “mere deceptions and playthings.” Gysi:‘” concluded that his tracing technique had only a 5-degree error. whereas wax and compound bites had a 25-degree error. Criticisms of Gothic arch tracings stated that equalization of pressures did not occur, prognathic or retrognathic patients could not be used, and flabby tissues or large tongues could cause shifting of bases.‘ Payne” stated that the tracing was difficult to see and too much patient cooperation was needed. Trapozzano ‘-I believed that “checkbites” were far more accurate than the central bearing point could possibly be, due to the unequal pressure produced. Block”’ made the point that any sore spot under the baseplate could cause an eccentric tracing. Grange?: stated that the Gothic arch produced was generally rounded and was not precise enough. FUNCTIONAL
RECORDINGS
Functional records were described in dental literature as early as 1910. Greene’ used a pumice and plaster mixture in one of the rims and instructed the patient to grind the rims together. The denture teeth were set to the generated paths. Needles-l” mounted three studs on maxillary rims which cut arrow tracings into mandibular compound rims. .4fter removal from the mouth, the rims were reassembled with the functinal grooves. Patterson”’ cut a trough in the upper and lower rims. These were filled with a Carborundum and plaster mixture. The patient would move his jaw and grind the rims until the proper curvature had been established. This would ensure equalized pressure and uniform tooth contact in all excursions. The functional technique developed by Meyer”” used soft wax occlusion rims. Tinfoil was placed over the wax and lubricated. The patient performed the functional movements to produce a wax path. A plaster index was made of the wax path and the teeth were set to the plaster index. BOOS” used the Gnathodynamometer to determine the vertical and horizontal position at which a maximum biting force could tx produced. His
143
MYERS
Bimeter was mounted on the lower occlusion rim with a central bearing point against a plate on the upper occlusion rim. Plaster registrations were made with the Bimeter in the mouth and the patient exerting pressure. Boos theorized that optimum occlusal position and the position of maximum biting force would coincide. He also thought that it was essential that all registrations be made under biting force so that the displacement of soft tissues which occur in function, would occur during bite registration.j*, 53 Shanahan,j4 in his physiologic technique, placed cones of soft wax on the mandibular rim and had the patient swallow several times. During swallowing, the tongue forced the mandible into its centric relation position. The cones of soft wax were moved and the physiologic centric relation was recorded. CEPHALOMETRICS The use of cephalometrics to record centric relation was described by Pyott and Schaeffer.55 The proper centric relation and vertical dimension of occlusion were determined by cephalometric radiographs. This method, however, was somewhat impractical and never gained widespread usage. It is apparent from the dental literature, that there are many opinions and much confusion concerning centric relation records. One would have to agree with Sear9 who wrote 3 “The problem has confused a great number of readers, which is not surprising, as many of the writers are also confused.” BOOSTS probably came closest to the solution when he stated that “in normal cases, the .occlusion, the temporomandibular joints, the bone, the soft tissue, and the musculature all produce the same relation to each other and any one of the many registration techniques may be used.” A certain technique might be required for an unusual situation or a problem patient. In the final analysis, the skill of the dentist and the cooperation of the patient are probably the most important factors in securing an accurate centric relation record. REFERENCES 1. Swenson, M. G.: Complete Dentures, ed 6. St. Louis, 1970, The C. V. Mosby Co. 2. Nagle, R. J., and Sears, V. H.: Denture Prosthetics, ed 2. St. Louis, 1962, The C. V. Mosby Co. 3. Gehl, D. H., and Dresen, 0. M.: Complete Denture Prosthesis, ed 4. Philadelphia, 1948, W. B. Saunders Co. 4. Academy of Denture Prosthetics: Glossary of prosthodontic terms, ed 2. J PROSTHETDENT 6:13, 1960. 5. Kingery, R. H.: Problems associated with centric relation. J PROSTHET DENT 2:307, 1952.
144
6.
7. 8. 9. 10. 11.
12. 13. 14. 15. 16. 17. 18.
19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35.
Schlosser, R. 0.: Methods of securing centric relation and other positional relation records in complete denture prosthesis. J Am Dent Assoc 28:17, 1941. Greene, J. W.: Greene Brothers’ Clinical Course in Dental Prosthesis, 1910. Christensen, C.: The problem of the bite. Dent Cosmos 47:1184, 1905. Prothero, J. H.: Prosthetic Dentistry. Chicago, 1921, Medical-Dental Publishing Co. Brown, J. C.: Articular mechanisms for inducing condyle migration. J PROSTHET DENT 4:208, 1954. Wright, W. H.: Use of intraoral jaw relation wax records in complete denture prosthesis. J Am Dent Assoc 26~542, 1939. Schuyler, C.: Intraoral method of establishing maxillomandibular relation. J Am Dent Assoc 19:1012, 1932. Brill, N.: Reflexes, registrations, and prosthetic therapy. J PROSTHET DENT 7:341, 1957. Trapozzano, V. R.: Occlusal records. J PROSTHET Dwr 5~325, 1955. Payne, S. H.: Selective occlusion. J PROSTHET DENT 5:302, 1955. Hickey, J. C.: Centric relation-A must for complete dentures. Dent Clin North Am, November, 1964. Boos, R. H.: Centric relation and functional areas. J PROSTHET DENT 9: 191, 1959. Hanau, R. L.: Why Is Centric Relation Once Established Not Retained Subsequently? Unpublished Paper, Northwestern University Dental School Library, 1929. Hanau, R. L.: Dental Engineering, vol I, part II. Buffalo, 1927, Hanau Engineering Co. Block, L. S.: Common factors in complete denture prosthetics. J PROSTHETDENT 3:736, 1953. Jamieson, C. H.: A modern concept of complete dentures. J PRO~THET DENT 6~582, 1956. Trapozzano, V. R.: An analysis of current concepts of occlusion. J PRO~THETDENT 5:764, 1955. Kazis, H.: Functional aspects of complete mouth rehabilitation. J PROSTHETDENT 2:575, 1952. Boucher, C. 0.: Current status of prosthodontics. J PROSTHET DENT 10:421, 1960. Yasaki, M.: The height of the occlusion rim and the interocclusal distance. J PROSTHETDENT 11:26, 1961. Lucia, V. 0.: Modern Gnathological Concepts. St. Louis, 1961, The C. V. Mosby Co. Beck, H.: Selection of an articulator and jaw registration. J PRO~THET DENT 10:884, 1960. Simpson, H.: Registration of centric relation in complete denture prosthesis. J Am Dent Assoc 26:1682, 1939. Phillips, G. B.: Fundamentals in the mandibular movements in edentulous mouths. J Am Dent Assoc 14:409, 1927. Gysi, A.: Practical application of research results in denture construction. J Am Dent Assoc 16:199, 1929. Page, H. L.: Maxillomandibular terminal relationships. Dent Dig 57:490, 1951. Balkwill, F. H.: The best form and arrangement of artificial teeth for mastication. Br J Dent Sci 9:278, 1866. Sears, V. H.: Centric jaw relation. Dent Dig 58:302, 1952. Gysi, A.: The problem of articulation. Dent Cosmos 52:1, 1910. Clapp, G. W.: Prosthetic Articulation. New York, 1914, The Dentists Supply Co.
FEBRUARY
1982
VOLUME
47
NUMBER
2
CENTRK
RELATION
RECORDS
36.
Sears, V. H.: Jaw relations and a means of recording the most important articulator adjustment. Dent Cosmos 68:1047. 1926. 37. Stansbery. C. J.: Functional position checkbite technique. J Am Dent Assoc 16:421, 1929. 38. Hall, R. E.: Full denture construction. J Am Dent Assoc 16:1157, 1929. 39. Hardy, I. R.: Technique for use of nonanatomic acrylic posterior teeth. Dent Dig 48:562, 1942. 40 Pleasure, M. A.: Occlusion of cuspless teeth for balance and comfort. J PROSTHET DENT 5:305, 1955. 41. Porter, C. G.: The cuspless centralized occlusal pattern. J PROSTHET DENT 5:313, 1955. 42 Kapur, K. K., and Yurkstas, A. A.: An evaluation of centric relation records obtained by various techniques. J PROWHET DENT 7:770,
43
1957.
Robinson, S. C.: Equilibrated THET DENT 2462,
44
45. 46
functional
occlusion. J PROS-
1952.
Silverman, M. M.: Centric occlusion and jaw relations and fallacies of current concepts. J PROSTHET DENT 7~750, 1957. Hanau, R.: The relation between mechanical and anatomical articulation. J Am Dent Assoc 10:776, 1923. Tenth, R. W.: Interpretation and registration of mandibulomaxillary relations and their reproduction in an instrument. J Am Dent Assoc 13:1675, 1926.
THE JOURNAL
OF PROSTHETIC
DENTISTRY
&anger, E.: Centric relation. J PROSI.IIET DENT 2:160, 1952. 48. Needles, J. W.: Practical uses of curve of Spee. J Am Dent Assoc l&918, 1923. 49. Patterson, A. H.: ConstructIon of artificial dentures. Dent Cosmos 65:679, 1923. 50. Meyer, F. S.: A new, simple and accurate technique for obtaining balanced and functional ncclwion J .4m Dent Assoc 21:195, 1934. relation established by biting 51. Boos, R. H.: Intermaxillary power. J Am Dent Assoc 27:1192, 1940. 52. Boos, R. H.: Occlusion from rest position. ,I PRCXTHET DENT 2:575, 1952. 53. Boos, R. H.: Basic anatomic factors of jaw position. J PROSTHET DENT 4:200, 1954. 54. Shanahan, T. E.: Physiologic jaw relations and occlusion of complete dentures. J PROSTHET DENT 5:319, 1955. 55. Pyott, J. E., and Schaeffer. A.: Simullaneous recording of centric occlusion and vertical dimension. .f Am Dent Asoc 44:430, 1952 Reprint requeststo: 47.
DR. MICHAEL L. MYERS MEDICAL UNIVERSITY DF SOUTH CAROLINA COLLEGE OF DENTAL MEDICINE 171 ASHLEY AVE. CHARLESTON, SC: 29425
145