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Development of occlusion where total reconstruction is contraindicated
DEVELOPMENT OF OCCLUSION WHERE TOTAL RECONSTRUCTION IS CONTRAINDICATED WILLIAM H. PRUDEN, Paterson, N. .I.
E
II, D.D.S.
on complete mouth treatment is altogether fitting and proper as long as the dentist remembers that the objective of restorative dentistry should be to do the least amount of dentistry required for a given patient. A comprehensive diagnosis including complete history, clinical examination, mounted diagnostic casts, and roentgenograms serves the best interests of our patients. However, it does not necessarily follow that our treatment plans should include a restoration on every tooth. Striving for the ideal is a noble aim but a foolish one if the nonideal is also functional and nonpathologic. Methods of developing an occlusion as it affects the mouth that does not need full treatment will be presented in this article. THE
MPHASIS
ONE
TOOTH
RESTORATION
A full mouth rehabilitation might consist of a single onlay or crown if this were all the dental treatment needed in a specific situation. The patient with many large amalgam restorations, one of which fractures with the loss of a cusp, is an example. If the diagnosis shows good functional occlusion with good alignment of teeth, well carved and contoured restorations, and good periodontal health, we would be foolish to suggest replacement of all restorations in an attempt to achieve the ideal. We would be assuming a great deal to presume to improve on an already h.ealthy condition. The occlusion of the one crown or onlay being constructed must receive as much care as would be given a full mouth restoration. A fine-fitting restoration with imporper occlusion could conceivably create a situation so unfavorable as to require extensive restoration at a future date. A deflective contact of this restoration might cause repositioning of the mandible with resulting new neuromuscular habits. This could lead to trauma and destruction in other parts of the mouth. FUNCTIONALLY
GENERATED
PATHS
The functional core technique for establishing the occlusal surface is ideal vvhen one tooth must be restored and the remainder of the mouth shows good functional occlusion and is nonpathologic. A soft wax is placed in the inlay preparation Read before
the American
Dental
Association,
Atlantic 649
City,
N. J.
550
PRUDEN
J. Pros. Den. May-June, 1966
or over the crown preparation within a short copper band matrix. Then, the patient carves the wax with the opposing teeth so that the pattern will be formed harmoniously with all functional and nonfunctional mandibular movements. A stone core or index is obtained of this wax surface, and the core can be used as the counter die for the wax pattern of the in1ay.l As long as the core can be positioned on the adjacent teeth, the pattern and subsequently the cast restoration will be in normal occlusion not only in the centric position but in any other occlusal position. The functionally generated path technique can be very successful in quadrant dentistry or even for total reconstruction where proper anterior guidance has been previously established. However, this method should not be used to develop the occlusion in eccentric positions opposite an extruded tooth or to form lateral pathways in a pathologically involved dentition where centric occlusion is not in harmony with centric relation. In these situations, previous occlusal corrections or extensive restorations should be made to provide a harmonious functional occlusion. THE
SINGLE
POSTERIOR
FIXED
PARTIAL
DENTURE
The handling of the occlusion is a diagnostic problem for a fixed partial denture, or for several individual tooth castings .in the same quadrant of the dental arch. If the rest of the mouth is healthy, the quadrant requiring treatment should be restored in harmony with the remaining dentition. Full working casts can be occluded more easily and with greater accuracy than casts of a part of the dental arch, and they also act as a guide for the technician when carving wax patterns. He can refer to the contours and occlusal anatomy of the teeth on the opposite side.z Periodontal problems in other parts of the mouth that cannot be explained by local irritation or systemic factors may be related to occlusion. Mounted diagnostic casts will furnish valuable information in this region.3 When centric occlusion is not in harmony with centric relation, the casts aid in determining whether equilibration, reconstruction, or a combination of both will best serve to obtain a harmonious relationship. Occlusal equilibration is at best a gross procedure and strictly a negative one. Any grinding procedure can only remove tooth structure. Equilibration should never be done prophylactically When it is employed, it should be done very carefully with a method that most likely will harmonize the maximum intercuspation of teeth with centric relation (that position to which the closing muscles of mastication would carry the mandible if the teeth were not in the way). Equilibration procedures should eliminate interferences on the balancing side at least while developing cuspid contacts on the working side. THE
RESTORATION
OF ONE DENTAL
ARCH
Sometimes a harmonious occlusion can be established with a combination of reconstruction in one dental arch and occlusal corrections on the other. Often, the restorations can be constructed in centric position because the opposing posterior teeth are out of contact following completion of the preparations in the involved arch. Some equilibrating of the teeth in the opposing dental arch will probably be indi-
V&me Number
16 3
OCCLUSION
DEVELOPMENT
551
ca.ted. Usually these teeth will have extruded creating a poor plane of occlusion which, if not corrected, will result in traumatic or inefficient occlusion. This principle of rebuilding the occlusion in centric relation can be employed when the teeth to be restored are in one dental arch or are in the right quadrant of one jaw and left quadrant of the other. Any of these conditions eliminates all contacts of posterior teeth after the preparations are completed. In this type of procedure, locating and transferring the hinge-axis to the articulator and obtaining proper centric registrations will lead to increased accuracy.2+6 However, remounting procedures are not as effective as in the full mouth reconstruction situation because wear on the stone counter cast is likely to 0c:cur. REXTORING
THREE
QUADRANTS
Occasionally extensive restorative treatment is necessary in three quadrants of the mouth and yet the fourth quadrant is sound. If the periodontal condition is healthy, the alignment of the teeth adequate, and caries activity controlled, this quadrant need not be involved. The patient would be treated in much the same way as for complete restoration of all posterior teeth except that the teeth of the fourth quadrant would only be involved with reshaping or recontouring procedures. Here again the use of the hinge axis, proper centric relation records, and remounting procedures are a decided aid. Frosting or sand blasting the occlusal surfaces and temporary placement of the restorations can be of value in refining the occlusion. A careful analysis of the marks on the occlusal surfaces of the castings must be made before alteration is begun. OCCLI’SION
FOR
ANTERIOR
TEETH
The anterior teeth must harmonize with the remainder of the occlusion. An anterior fixed partial denture, for example, must not prevent contact of the posterior teeth nor must it overload any tooth in the anterior segment either during closure, in centric position, or in any eccentric excursion. Some confusion exists regarding the role of the cuspids. Some dentists feel that these teeth shou!d be slightly out of contact when the mandible is in centric relation while others feel they should contact simultaneously with the posterior teeth. Clinical observation indicates that they must at least function in the working excursion and many believe that they should support the occlusion at this time. When the cuspid is out of contact in the lateral excursion, the premolars often become mobile. W’hether the increased root length of the cuspid, its increased proprioception, or evolutionary factors are responsible for the protective maintenance that it provides is not completely clear.7,s Crowns should not be placed on lower anterior teeth if they can be avoided. The size of these teeth makes esthetics and proper contours of the restorations difficult problems. Where fixed prostheses or stabilization are necessary, pin-ledge retainers are preferred. If both posterior and anterior restorations are indicated, the posterior restorations are completed first, with an arbitrary incisal guidance which is later fabricated
552
J. Pros. Den. May-June, 1966
PRUDEN
in the anterior teeth. However, the anterior guidance or at least cuspid guidance must be established first when the generated path technique is used, because the cuspids must support the occlusion during the subsequent operative procedures.n SPLINTING
IN
OCCLUSAL
DEVELOPMENT
Splinting of teeth is merely an adjunct to occlusion. Splinting is not a substitute for good occlusion. However, in a harmonious occlusal relation, splinting can be of great aid in supporting fixed restorations and/or periodontally weakened teeth. Most dentists tend to think of splinting as being developed by solder joints only. However, perfectly adequate splinting can be obtained where parallelism is a problem or might jeopardize the pulp by dove-tailing one casting into another. Likewise, the use of cemented copings with telescopic crowns may achieve a form of splinting. Two or more fixed partial dentures can be connected to develop complete arch splinting by the use of underlying connected copings on adjacent teeth. THE
IMPORTANCE
OF PRECISION
IN
DEVELOPMENT
OF OCCLUSION
The fabricating of an occlusion presupposes precise techniques. Anything that increases accuracy is worth doing. The vacuum mixing of die stones before pouring casts, proper measuring of all materials, vacuum investing procedures, and the use of modern equipment to eliminate as much of the human factor as possible are all important adjuncts, Their use will help to insure not only accurately fitting restorations but restorations with harmonious occlusion. Nonetheless, all patients for whom restorations have been made, be they large or small, should be recalled for observation of the occlusion. Proper adjustment of wear facets may save trouble for both the dentist and the patient. SUMMARY
Methods of development of harmonious occlusion for patients who do not require complete mouth reconstruction were described. Treatment procedures ranged from single tooth restorations to three quadrants requiring dental reconstruction. By practicing the basic tenents of gnathology in treatment of the simple restorations in conjunction with proper periodontal care, the complex, time consuming, patient fatiguing, full mouth rehabilitation can be avoided for many patients. REFERENCES
1. Benfield, J. : in Kilpatrick, H. : Work Simplification in Dental Practice; Applied Time and Motion Studies, Philadelphia, 1963, W. B. Saunders Company. ‘2. Pruden, W. H., II: Occlusion Related to Fixed Partial Denture Prosthesis, D. Clin. North America, p. 121-136, March, 1962. 3. Pruden, W. H., II: The Role of Study Casts in Diagnosis and Treatment Planning, J. PROS. DENT. 10:707-710, 1960. 4. Wilson, W. H., and Lang, R. L.: Practical Crown and Bridge Prosthodontics, New York, 1962, McGraw-Hill Book Company, Inc. 5. Lucia, V. 0.: Modern Gnathological Concepts, St. Louis, 1961, The C. V. Mosby Company. 6. Granger, E. R.: Practical Procedures in Oral Rehabilitation, Philadelphia, 1%2, J. B. Lippincott Company.
Volume 16 Number 3
OCCLUSION
DEVELOPMENT
553
7. D’Amico, A. : The Canine Teeth-Normal Functional Relation of the Natural Teeth of Man, J. Southern California D.A. 26:6-23, 19.58. 8. Alexander, P. C.: Analysis of Cuspid Protective Occlusion, J. PROS. DENT. 13:309-317, 1963. 9. Mann, A. W., and Pankey, L. D.: Oral Rehabilitation. Part I. Use of the P-M Instrument in Treatment Planning and in Restoring the Lower Posterior Teeth. Part II. Reconstruction of the Upper Teeth Using a Functional Generated Path Technique, J. PROS. DENT. 10:135-162, 1960. 44 CHURCH PATERSON,
ST.
N. J. 07505
E
II, D.D.S.
on complete mouth treatment is altogether fitting and proper as long as the dentist remembers that the objective of restorative dentistry should be to do the least amount of dentistry required for a given patient. A comprehensive diagnosis including complete history, clinical examination, mounted diagnostic casts, and roentgenograms serves the best interests of our patients. However, it does not necessarily follow that our treatment plans should include a restoration on every tooth. Striving for the ideal is a noble aim but a foolish one if the nonideal is also functional and nonpathologic. Methods of developing an occlusion as it affects the mouth that does not need full treatment will be presented in this article. THE
MPHASIS
ONE
TOOTH
RESTORATION
A full mouth rehabilitation might consist of a single onlay or crown if this were all the dental treatment needed in a specific situation. The patient with many large amalgam restorations, one of which fractures with the loss of a cusp, is an example. If the diagnosis shows good functional occlusion with good alignment of teeth, well carved and contoured restorations, and good periodontal health, we would be foolish to suggest replacement of all restorations in an attempt to achieve the ideal. We would be assuming a great deal to presume to improve on an already h.ealthy condition. The occlusion of the one crown or onlay being constructed must receive as much care as would be given a full mouth restoration. A fine-fitting restoration with imporper occlusion could conceivably create a situation so unfavorable as to require extensive restoration at a future date. A deflective contact of this restoration might cause repositioning of the mandible with resulting new neuromuscular habits. This could lead to trauma and destruction in other parts of the mouth. FUNCTIONALLY
GENERATED
PATHS
The functional core technique for establishing the occlusal surface is ideal vvhen one tooth must be restored and the remainder of the mouth shows good functional occlusion and is nonpathologic. A soft wax is placed in the inlay preparation Read before
the American
Dental
Association,
Atlantic 649
City,
N. J.
550
PRUDEN
J. Pros. Den. May-June, 1966
or over the crown preparation within a short copper band matrix. Then, the patient carves the wax with the opposing teeth so that the pattern will be formed harmoniously with all functional and nonfunctional mandibular movements. A stone core or index is obtained of this wax surface, and the core can be used as the counter die for the wax pattern of the in1ay.l As long as the core can be positioned on the adjacent teeth, the pattern and subsequently the cast restoration will be in normal occlusion not only in the centric position but in any other occlusal position. The functionally generated path technique can be very successful in quadrant dentistry or even for total reconstruction where proper anterior guidance has been previously established. However, this method should not be used to develop the occlusion in eccentric positions opposite an extruded tooth or to form lateral pathways in a pathologically involved dentition where centric occlusion is not in harmony with centric relation. In these situations, previous occlusal corrections or extensive restorations should be made to provide a harmonious functional occlusion. THE
SINGLE
POSTERIOR
FIXED
PARTIAL
DENTURE
The handling of the occlusion is a diagnostic problem for a fixed partial denture, or for several individual tooth castings .in the same quadrant of the dental arch. If the rest of the mouth is healthy, the quadrant requiring treatment should be restored in harmony with the remaining dentition. Full working casts can be occluded more easily and with greater accuracy than casts of a part of the dental arch, and they also act as a guide for the technician when carving wax patterns. He can refer to the contours and occlusal anatomy of the teeth on the opposite side.z Periodontal problems in other parts of the mouth that cannot be explained by local irritation or systemic factors may be related to occlusion. Mounted diagnostic casts will furnish valuable information in this region.3 When centric occlusion is not in harmony with centric relation, the casts aid in determining whether equilibration, reconstruction, or a combination of both will best serve to obtain a harmonious relationship. Occlusal equilibration is at best a gross procedure and strictly a negative one. Any grinding procedure can only remove tooth structure. Equilibration should never be done prophylactically When it is employed, it should be done very carefully with a method that most likely will harmonize the maximum intercuspation of teeth with centric relation (that position to which the closing muscles of mastication would carry the mandible if the teeth were not in the way). Equilibration procedures should eliminate interferences on the balancing side at least while developing cuspid contacts on the working side. THE
RESTORATION
OF ONE DENTAL
ARCH
Sometimes a harmonious occlusion can be established with a combination of reconstruction in one dental arch and occlusal corrections on the other. Often, the restorations can be constructed in centric position because the opposing posterior teeth are out of contact following completion of the preparations in the involved arch. Some equilibrating of the teeth in the opposing dental arch will probably be indi-
V&me Number
16 3
OCCLUSION
DEVELOPMENT
551
ca.ted. Usually these teeth will have extruded creating a poor plane of occlusion which, if not corrected, will result in traumatic or inefficient occlusion. This principle of rebuilding the occlusion in centric relation can be employed when the teeth to be restored are in one dental arch or are in the right quadrant of one jaw and left quadrant of the other. Any of these conditions eliminates all contacts of posterior teeth after the preparations are completed. In this type of procedure, locating and transferring the hinge-axis to the articulator and obtaining proper centric registrations will lead to increased accuracy.2+6 However, remounting procedures are not as effective as in the full mouth reconstruction situation because wear on the stone counter cast is likely to 0c:cur. REXTORING
THREE
QUADRANTS
Occasionally extensive restorative treatment is necessary in three quadrants of the mouth and yet the fourth quadrant is sound. If the periodontal condition is healthy, the alignment of the teeth adequate, and caries activity controlled, this quadrant need not be involved. The patient would be treated in much the same way as for complete restoration of all posterior teeth except that the teeth of the fourth quadrant would only be involved with reshaping or recontouring procedures. Here again the use of the hinge axis, proper centric relation records, and remounting procedures are a decided aid. Frosting or sand blasting the occlusal surfaces and temporary placement of the restorations can be of value in refining the occlusion. A careful analysis of the marks on the occlusal surfaces of the castings must be made before alteration is begun. OCCLI’SION
FOR
ANTERIOR
TEETH
The anterior teeth must harmonize with the remainder of the occlusion. An anterior fixed partial denture, for example, must not prevent contact of the posterior teeth nor must it overload any tooth in the anterior segment either during closure, in centric position, or in any eccentric excursion. Some confusion exists regarding the role of the cuspids. Some dentists feel that these teeth shou!d be slightly out of contact when the mandible is in centric relation while others feel they should contact simultaneously with the posterior teeth. Clinical observation indicates that they must at least function in the working excursion and many believe that they should support the occlusion at this time. When the cuspid is out of contact in the lateral excursion, the premolars often become mobile. W’hether the increased root length of the cuspid, its increased proprioception, or evolutionary factors are responsible for the protective maintenance that it provides is not completely clear.7,s Crowns should not be placed on lower anterior teeth if they can be avoided. The size of these teeth makes esthetics and proper contours of the restorations difficult problems. Where fixed prostheses or stabilization are necessary, pin-ledge retainers are preferred. If both posterior and anterior restorations are indicated, the posterior restorations are completed first, with an arbitrary incisal guidance which is later fabricated
552
J. Pros. Den. May-June, 1966
PRUDEN
in the anterior teeth. However, the anterior guidance or at least cuspid guidance must be established first when the generated path technique is used, because the cuspids must support the occlusion during the subsequent operative procedures.n SPLINTING
IN
OCCLUSAL
DEVELOPMENT
Splinting of teeth is merely an adjunct to occlusion. Splinting is not a substitute for good occlusion. However, in a harmonious occlusal relation, splinting can be of great aid in supporting fixed restorations and/or periodontally weakened teeth. Most dentists tend to think of splinting as being developed by solder joints only. However, perfectly adequate splinting can be obtained where parallelism is a problem or might jeopardize the pulp by dove-tailing one casting into another. Likewise, the use of cemented copings with telescopic crowns may achieve a form of splinting. Two or more fixed partial dentures can be connected to develop complete arch splinting by the use of underlying connected copings on adjacent teeth. THE
IMPORTANCE
OF PRECISION
IN
DEVELOPMENT
OF OCCLUSION
The fabricating of an occlusion presupposes precise techniques. Anything that increases accuracy is worth doing. The vacuum mixing of die stones before pouring casts, proper measuring of all materials, vacuum investing procedures, and the use of modern equipment to eliminate as much of the human factor as possible are all important adjuncts, Their use will help to insure not only accurately fitting restorations but restorations with harmonious occlusion. Nonetheless, all patients for whom restorations have been made, be they large or small, should be recalled for observation of the occlusion. Proper adjustment of wear facets may save trouble for both the dentist and the patient. SUMMARY
Methods of development of harmonious occlusion for patients who do not require complete mouth reconstruction were described. Treatment procedures ranged from single tooth restorations to three quadrants requiring dental reconstruction. By practicing the basic tenents of gnathology in treatment of the simple restorations in conjunction with proper periodontal care, the complex, time consuming, patient fatiguing, full mouth rehabilitation can be avoided for many patients. REFERENCES
1. Benfield, J. : in Kilpatrick, H. : Work Simplification in Dental Practice; Applied Time and Motion Studies, Philadelphia, 1963, W. B. Saunders Company. ‘2. Pruden, W. H., II: Occlusion Related to Fixed Partial Denture Prosthesis, D. Clin. North America, p. 121-136, March, 1962. 3. Pruden, W. H., II: The Role of Study Casts in Diagnosis and Treatment Planning, J. PROS. DENT. 10:707-710, 1960. 4. Wilson, W. H., and Lang, R. L.: Practical Crown and Bridge Prosthodontics, New York, 1962, McGraw-Hill Book Company, Inc. 5. Lucia, V. 0.: Modern Gnathological Concepts, St. Louis, 1961, The C. V. Mosby Company. 6. Granger, E. R.: Practical Procedures in Oral Rehabilitation, Philadelphia, 1%2, J. B. Lippincott Company.
Volume 16 Number 3
OCCLUSION
DEVELOPMENT
553
7. D’Amico, A. : The Canine Teeth-Normal Functional Relation of the Natural Teeth of Man, J. Southern California D.A. 26:6-23, 19.58. 8. Alexander, P. C.: Analysis of Cuspid Protective Occlusion, J. PROS. DENT. 13:309-317, 1963. 9. Mann, A. W., and Pankey, L. D.: Oral Rehabilitation. Part I. Use of the P-M Instrument in Treatment Planning and in Restoring the Lower Posterior Teeth. Part II. Reconstruction of the Upper Teeth Using a Functional Generated Path Technique, J. PROS. DENT. 10:135-162, 1960. 44 CHURCH PATERSON,
ST.
N. J. 07505