DENTAL DANIEL
TECHNOLOGY
H. GEHL. Section editor
Porcelain
occlusal
posterior
fixed
partial
dentures
Hubert T. Chandler, D.D.S.,* James 5. Brudvik, D.D.S.,** William J. Pagan, D.D.S.*** Walter Reed Army Medical Center, Washington, D. C.
and
F
ull porcelain coverage for posterior fixed partial dentures and crowns is becoming increasingly popular. However, extensive grinding of the occlusal surfaces of these restorations at the time of insertion is often necessary to achieve occlusal harmony. Then, the rough surfaces require time-consumin g laboratory work to minimize the abrasive qualities of the porcelain. Many techniques have been advocated for the development of occlusal patterns during the construction of crowns and fixed partial dentures to minimize intraoral adjustment. Each of these techniques has advantages and disadvantages. We have found that the functionally generated-path technique offers a high degree of accuracy and simplicity in the fabrication of short-span fixed partial dentures and crowns with complete porcelain occlusal surfaces.lm4 INDICATIONS This technique is particularly useful for patients who have an acceptable centric occlusion and exhibit an occlusal scheme with group function (Fig. 1). The generated-path technique uses the existing noninvolved teeth in developing an occlusion for the restoration that is group-function oriented. If the existing occlusal scheme is to be altered during fabrication or if group function is not desired, then other techniques should be employed. TECHNIQUE ( 1) Prepare the selected abutments for complete crown retainers (Fig. 2). Provide adequate occlusal reduction to allow sufficient space for the metal framework The opinions or assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. *Colonel, DC, USA. **Colonel, DC, USA. ***Formerly, Lieutenant Colonel, DC, USA. 583
584
Chandler,
Brudvik,
and Pagan
J. Prosthet. Dent. November, 197.5
Fig. 1. Patient with acceptable centric occlusion and group function. Fig. 2. The teeth are prepared for a porcelain occlusal fixed partial denture.
and porcelain veneer. Normally, 2 mm. of clearance in centric and eccentric occlusions are essential (2) Make full-arch im p ressions of both dental arches using the impression material of choice. (3 j To make a centric occlusion record, place a button of recording material (modeling compound or cold-curing acrylic resin) on the most posterior prepared abutment and have the patient close into maximum tooth interdigitation (centric occlusion) (4) Remove the record from the mouth, and trim it so that only the cusp tips of the prepared teeth and opposing teeth are apparent. If sufficient teeth remain to give a positive relation of the maxillary and mandibular casts, then no jaw relation record is necessary. The relation of the casts can be recorded for transmission to the laboratory by placing them in occlusion and drawing three widely separated vertical lines on the facial surfaces of the occluding teeth. (5) Mount the master and occluding casts on a suitable instrument (Verticulatar,” Fig. 3), (6) Fabricate a metal framework designed for full porcelain coverage using a ceramic-type alloy. After fabrication of the framework, the casts and mountings are retained for later use in construction of the restoration. (7) Try the framework in the mouth (Fig. 4). and check for marginal fit and adequate occlusal clearance. At least 1.5 mm. of clearance are needed in centric and eccentric occlusions. (8) Remove the framework from the mouth, and apply a layer of recording wax? to its occlusal surface. A thin layer of melted wax is applied to the surface, and then a small amount of softened wax is added (Fig. 5). (9) Place the metal framework with the softened wax in the mouth in its fully seated position. (10) Instruct the patient to tap the teeth in centric occlusion until the adjacent unprepared teeth arc in occlusion. “J. F. Jclenko i% Company, Inc., New Rochelle, N. Y. +Hi-Fi wax, J. F. Jelenko & Company, Inc., New Rochelle, N. 1’.
Fig. 3. The anatomic maxillary cast and master mandibular of occlusal clearance on prepared teeth. Fig, 4. The metal framework
Fig. 5. The recording Fig. 6. All occluding generated path.
is tried in the mouth
wax is applied contacts
cast are mounted.
and checked
Note the amount
for fit and occlusal
clearance.
to the metal framework.
on the stone template
have been ground
away
except
the
( 11) Instruct the patient to glide the mandible into lateral and protrusive positions, keeping the unprepared teeth in contact as a guide. The success of the technique in minimizing final occlusal adjustment is dependent upon recording all excursive movements. (12) Remove the framework from the mouth, being careful not to distort the wax. (13) Place the framework back on the original master cast. (14) Lubricate the teeth on the cast. (15) Form a generated-path occlusion template by painting artificial stone into the wax record, and invert the entire assembly into a I/Q inch thick patty of the same stone to a depth sufficient to record only the cusp tips of the unprepared tooth. (16) After it is fully set, trim the borders of the stone occlusion template without removing it from the master cast, and place the entire assembly back on the Verticulator. ( 17) Use a second top arm, and mount the template while the instrument is in the fully closed position.
586
Chandler,
Brudvik,
Fig. 7. The porcelain
J. I’rosthet. Dent November, 1975
and Pagan
occlusal surfaces are articulated
with
the anatomic
opposing
cast.
Fig. 8. The stone generated-path template is in position prior to correcting for eccentric movements. All interferences must be removed until the Verticulator can be fully closed.
jaw
(18) Remove the template from its position against the master cast after the mounting of the template is complete, and grind away all impressions of the unprepared teeth, leaving only that part reproduced from the generated path (Fig. 6). This step precludes the inadvertent entrapment of debris between the template and the unprepared teeth which would prevent full closure of the instrument during occlusal corrections. (19) Clean the metal framework. (20) Apply porcelain according to the manufacturer’s instructions. (21) Shape the porcelain to occlude with the anatomic-occlusion cast (Fig. 7) . Potential balancing-side interferences should be relieved at this time. (22) Replace the anatomic-occlusion cast with the generated-path (Fig. 8) template, and grind the porcelain until the Verticulator fully closes. (23) Mark the opposing porcelain, using a water-soluble die on the surface of the template, to eliminate the errors that would be caused by the thickness of articulating paper. (24) Smooth the occlusal surface of the porcelain with rubber wheels so that it will be relatively nonabrasive after glazing.’ (25) Stain and glaze the porcelain.
Volume 34 NIlmbcr 5
Porcelain
posterior
fixed partial
dentures
587
(26) Try the restoration in the mouth and check for interferences in all mandibular excursions. Occlusal interferences should be minor or nonexistent if the technique has been carefully followed. (27) Cement the restoration in the mouth (Fig. 9).
DISCUSSION The full porcelain occlusal fixed partial denture or crown is particularly suited for use with the functionally generated-path technique. The use of this technique for restorations with metal occlusal surfaces necessitates the fabrication of a resin or metal tray to support the wax for the generated path, This custom tray may or may not fit the mouth in exactly the same manner that it fits the master cast. In the technique described, the actual metal framework is used to support the wax in the mouth. The generated path is made on this framework in the exact position that the framework fits the prepared teeth, thus eliminating the possibility of error in transferring the generated path.
CONCLUSION A method for using the functionally generated-path technique to fabricate full occlusal porcelain-fused-to-metal fixed partial dentures and crowns has been described. Proper use of this technique in carefully selected patients should eliminate occlusal adjustments and the concomitant polishing and glazing that are often necessary before the restoration can be permanently cemented.
References 1. Meyer, F. S.: The Generated Path Technique in Reconstruction Dentistry, Part I. Complete Dentures, J. PROSTHET. DENT. 9: 354-366, 1959. 2. Meyer, F. S.: The Generated Path Technique in Reconstruction Dentistry, Part II. Fixed Partial Dentures, J. PROSTHET. DENT. 9: 432-440, 1959. 3. 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, J. PROSTHET. DENT. 10: 135-150, 1960. Part II. Reconstruction of the 4. Pankey, L. D., and Mann, A. W.: Oral Rehabilitation, Upper Teeth Using a Functionally Generated Path Technique, J. PROSTHET. DEST. 10: 151-162, 1960. 5. Monasky, G. E., and Taylor, D. F.: Studies on the Wear of Porcelain, Enamel, and Gold, J. PROSTHET. DENT. 25: 299-306, 1971. COLONEL CHANDLER DEPARTMENT OF THE ARMY OFFICE OF THE SURGEON GENERAL WASHINGTON,
D. C. 20310
COLONEL
BRUDVIK REGIONAL FORT SAM HOUSTON,
U. S. ARMY
DENTAL ACTIVITY TEXAS 78234
DR. PAGAN VETERANS ADMINISTRATION
CENTER
Box 4867 SAN JUAN,
PUERTO
RICO 00936
TECHNOLOGY
H. GEHL. Section editor
Porcelain
occlusal
posterior
fixed
partial
dentures
Hubert T. Chandler, D.D.S.,* James 5. Brudvik, D.D.S.,** William J. Pagan, D.D.S.*** Walter Reed Army Medical Center, Washington, D. C.
and
F
ull porcelain coverage for posterior fixed partial dentures and crowns is becoming increasingly popular. However, extensive grinding of the occlusal surfaces of these restorations at the time of insertion is often necessary to achieve occlusal harmony. Then, the rough surfaces require time-consumin g laboratory work to minimize the abrasive qualities of the porcelain. Many techniques have been advocated for the development of occlusal patterns during the construction of crowns and fixed partial dentures to minimize intraoral adjustment. Each of these techniques has advantages and disadvantages. We have found that the functionally generated-path technique offers a high degree of accuracy and simplicity in the fabrication of short-span fixed partial dentures and crowns with complete porcelain occlusal surfaces.lm4 INDICATIONS This technique is particularly useful for patients who have an acceptable centric occlusion and exhibit an occlusal scheme with group function (Fig. 1). The generated-path technique uses the existing noninvolved teeth in developing an occlusion for the restoration that is group-function oriented. If the existing occlusal scheme is to be altered during fabrication or if group function is not desired, then other techniques should be employed. TECHNIQUE ( 1) Prepare the selected abutments for complete crown retainers (Fig. 2). Provide adequate occlusal reduction to allow sufficient space for the metal framework The opinions or assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. *Colonel, DC, USA. **Colonel, DC, USA. ***Formerly, Lieutenant Colonel, DC, USA. 583
584
Chandler,
Brudvik,
and Pagan
J. Prosthet. Dent. November, 197.5
Fig. 1. Patient with acceptable centric occlusion and group function. Fig. 2. The teeth are prepared for a porcelain occlusal fixed partial denture.
and porcelain veneer. Normally, 2 mm. of clearance in centric and eccentric occlusions are essential (2) Make full-arch im p ressions of both dental arches using the impression material of choice. (3 j To make a centric occlusion record, place a button of recording material (modeling compound or cold-curing acrylic resin) on the most posterior prepared abutment and have the patient close into maximum tooth interdigitation (centric occlusion) (4) Remove the record from the mouth, and trim it so that only the cusp tips of the prepared teeth and opposing teeth are apparent. If sufficient teeth remain to give a positive relation of the maxillary and mandibular casts, then no jaw relation record is necessary. The relation of the casts can be recorded for transmission to the laboratory by placing them in occlusion and drawing three widely separated vertical lines on the facial surfaces of the occluding teeth. (5) Mount the master and occluding casts on a suitable instrument (Verticulatar,” Fig. 3), (6) Fabricate a metal framework designed for full porcelain coverage using a ceramic-type alloy. After fabrication of the framework, the casts and mountings are retained for later use in construction of the restoration. (7) Try the framework in the mouth (Fig. 4). and check for marginal fit and adequate occlusal clearance. At least 1.5 mm. of clearance are needed in centric and eccentric occlusions. (8) Remove the framework from the mouth, and apply a layer of recording wax? to its occlusal surface. A thin layer of melted wax is applied to the surface, and then a small amount of softened wax is added (Fig. 5). (9) Place the metal framework with the softened wax in the mouth in its fully seated position. (10) Instruct the patient to tap the teeth in centric occlusion until the adjacent unprepared teeth arc in occlusion. “J. F. Jclenko i% Company, Inc., New Rochelle, N. Y. +Hi-Fi wax, J. F. Jelenko & Company, Inc., New Rochelle, N. 1’.
Fig. 3. The anatomic maxillary cast and master mandibular of occlusal clearance on prepared teeth. Fig, 4. The metal framework
Fig. 5. The recording Fig. 6. All occluding generated path.
is tried in the mouth
wax is applied contacts
cast are mounted.
and checked
Note the amount
for fit and occlusal
clearance.
to the metal framework.
on the stone template
have been ground
away
except
the
( 11) Instruct the patient to glide the mandible into lateral and protrusive positions, keeping the unprepared teeth in contact as a guide. The success of the technique in minimizing final occlusal adjustment is dependent upon recording all excursive movements. (12) Remove the framework from the mouth, being careful not to distort the wax. (13) Place the framework back on the original master cast. (14) Lubricate the teeth on the cast. (15) Form a generated-path occlusion template by painting artificial stone into the wax record, and invert the entire assembly into a I/Q inch thick patty of the same stone to a depth sufficient to record only the cusp tips of the unprepared tooth. (16) After it is fully set, trim the borders of the stone occlusion template without removing it from the master cast, and place the entire assembly back on the Verticulator. ( 17) Use a second top arm, and mount the template while the instrument is in the fully closed position.
586
Chandler,
Brudvik,
Fig. 7. The porcelain
J. I’rosthet. Dent November, 1975
and Pagan
occlusal surfaces are articulated
with
the anatomic
opposing
cast.
Fig. 8. The stone generated-path template is in position prior to correcting for eccentric movements. All interferences must be removed until the Verticulator can be fully closed.
jaw
(18) Remove the template from its position against the master cast after the mounting of the template is complete, and grind away all impressions of the unprepared teeth, leaving only that part reproduced from the generated path (Fig. 6). This step precludes the inadvertent entrapment of debris between the template and the unprepared teeth which would prevent full closure of the instrument during occlusal corrections. (19) Clean the metal framework. (20) Apply porcelain according to the manufacturer’s instructions. (21) Shape the porcelain to occlude with the anatomic-occlusion cast (Fig. 7) . Potential balancing-side interferences should be relieved at this time. (22) Replace the anatomic-occlusion cast with the generated-path (Fig. 8) template, and grind the porcelain until the Verticulator fully closes. (23) Mark the opposing porcelain, using a water-soluble die on the surface of the template, to eliminate the errors that would be caused by the thickness of articulating paper. (24) Smooth the occlusal surface of the porcelain with rubber wheels so that it will be relatively nonabrasive after glazing.’ (25) Stain and glaze the porcelain.
Volume 34 NIlmbcr 5
Porcelain
posterior
fixed partial
dentures
587
(26) Try the restoration in the mouth and check for interferences in all mandibular excursions. Occlusal interferences should be minor or nonexistent if the technique has been carefully followed. (27) Cement the restoration in the mouth (Fig. 9).
DISCUSSION The full porcelain occlusal fixed partial denture or crown is particularly suited for use with the functionally generated-path technique. The use of this technique for restorations with metal occlusal surfaces necessitates the fabrication of a resin or metal tray to support the wax for the generated path, This custom tray may or may not fit the mouth in exactly the same manner that it fits the master cast. In the technique described, the actual metal framework is used to support the wax in the mouth. The generated path is made on this framework in the exact position that the framework fits the prepared teeth, thus eliminating the possibility of error in transferring the generated path.
CONCLUSION A method for using the functionally generated-path technique to fabricate full occlusal porcelain-fused-to-metal fixed partial dentures and crowns has been described. Proper use of this technique in carefully selected patients should eliminate occlusal adjustments and the concomitant polishing and glazing that are often necessary before the restoration can be permanently cemented.
References 1. Meyer, F. S.: The Generated Path Technique in Reconstruction Dentistry, Part I. Complete Dentures, J. PROSTHET. DENT. 9: 354-366, 1959. 2. Meyer, F. S.: The Generated Path Technique in Reconstruction Dentistry, Part II. Fixed Partial Dentures, J. PROSTHET. DENT. 9: 432-440, 1959. 3. 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, J. PROSTHET. DENT. 10: 135-150, 1960. Part II. Reconstruction of the 4. Pankey, L. D., and Mann, A. W.: Oral Rehabilitation, Upper Teeth Using a Functionally Generated Path Technique, J. PROSTHET. DEST. 10: 151-162, 1960. 5. Monasky, G. E., and Taylor, D. F.: Studies on the Wear of Porcelain, Enamel, and Gold, J. PROSTHET. DENT. 25: 299-306, 1971. COLONEL CHANDLER DEPARTMENT OF THE ARMY OFFICE OF THE SURGEON GENERAL WASHINGTON,
D. C. 20310
COLONEL
BRUDVIK REGIONAL FORT SAM HOUSTON,
U. S. ARMY
DENTAL ACTIVITY TEXAS 78234
DR. PAGAN VETERANS ADMINISTRATION
CENTER
Box 4867 SAN JUAN,
PUERTO
RICO 00936
