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Laboratory procedures for fitting removable partial denture frameworks
La-hra~ procedures for fitting remwat denture frameworks William D. Gay, D.D.S.” Walter Reed Army Medical Center, Washington, D. C.
P
roperly fitting removable partial denture frameworks-in the mouth is usually done using a chloroform-gold rough mixture or a disclosing wax. Many authors also suggest relating the framework to the master cast prior to fitting it in the mouth.‘-3-This time-saving step of properly fitting the tooth- and tissue-contacting surfaces of the framework needs more emphasis. The undersides (tooth surfaces) of rests, clasps, and major and minor connectors should be finished a8 smooth as those surfaces that they approximate to obtain a uniform fit. The inability to adapt the framework precisely to the master caSt or the mouth can be attributed to several factors. Some of these are: (1) The surface of the master cast is more coarse than the polished abutment tooth. (2) The irregular surface of the refractory case. imparts a rough finish to the casting. (3) In the chrome-cobalt technique the casting is dimensionally smaller than the wax pattern.? This article describe8 a laboratory finishing technique that, if carefully done, greatly reduces the amount of chairside time necessary to adapt to a framework and produces a well-fitting removable partial denture. TECHNIQUE 1. Duplicate the master cast prior to blockout, and remove the stone above the retentive parts of the clasps. 2. Remove the sprue button and the flash after recovery of the casting using appropriate disks, burs, and stones (Fig. 1). The opinions or assertions herein are the private views of the author and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. *Lieutenant Colonel, DC, USA; Chief, Maxillofacial Prosthetics. TPersonal Communications: Murphy, P.W., 1974.
THEJOURNAL OF PIZOSTHETICDENTISTRY
Fig. 1. Flash is removed using a pointed stone in a highspeed’ lathe. 3. Under magnif&tion, carefully inspect the underside of the casting for bubbles or irregularities (Fig. 2). 4. Remove these irregularities with small pointed stones or burs and electropolish. 5. Spray a thin layer of zinc stearate disclosing powder* on the underside of the casting. 6. Place the framework on the duplicate cast and seat it until resistance is felt, using care so as not to abrade the cast. 7. Remove the framework and inspect the underside for spots of interference demonstrated in the powder. Relieve these spots carefully and repeat this procedure until the casting goes to place without abrading the cast (Figs. 3 and 4). Inspection of all surfaces of tooth contact on the framework will reveal that these areas are still extremely rough (Fig. 5). 8. Smooth the rough surfaces by burnishing with a small pointed stone and a rubber point, being *Indicating
Spray,
Ney Co., Bloomfield,
Conn
227
Fig. 5. The coarse appearance al of interferences.
of framework
Fig. 3. Stone superior to retentive surfaces is removed on the duplicate cast.
Fig. 6. The tooth-contacting surfaces appear prior to trial in the mouth.
Fig. 4. The casting is completely cast.
Fig. 7. The framework after minimal properly positioned in the mouth.
seated on the duplicate
careful not to change the contours. Buff lightly to a high shine (Fig. 6). 9. Place the framework on the master cast. If the stone above the retentive portions of the clasps is removed, the framework should fully seat without abrading the cast. If not, steps No. 5 through 8 may be repeated.
228
after rem
as they
should
adjustments
is
SUMMARY A technique has been described for fitting a removable partial denture framework to the master cast prior to adapting it in the mouth. Emphasis should be placed on maintaining the original contour of the framework throughout the procedure. The amount of metal removed should be only that
AUGUST
1978
VOLUME
40
NUMBER
2
FITTING
REMOVABLE
PARTIAL
DENTURE
FRAMEWORKS
necessary to seat the casting on the master cast without abrading the stone. When finishing the tooth-contacting surfaces of the casting, very light pressure should be used to burnish the rough surfaces, not reduce them. If these steps are accomplished carefully in the laboratory, the dentist should be able to fit the framework in the mouth in a minimum of time (Fig. 7).
2.
3.
requests
Reprint Da.
WILLIAM
CHIEF,
to: D. Gnu
MAXILLOPACIAI.
WALTER
REFERENCES 1.
Applegate, 0. C.: Essentials of Removable Partial Denture Prosthesis, ed 3. Philadelphia, 1966, W. B. Saunders Company, p 361. Henderson, D., and Steffel, V.: McCracken’s Partial Denture Construction, ed 4. St. Louis, 197 1. The C. V. Mosby Company, pp 364, 400.
REED
WASHINGTON,
ARMY
PROSTHETICS MEDICAL
SERVICE
CENTER
D. C. 20012
Dykema, R. W., Cunningham, D. M., and Johnson, J. F.: Modern Practice in Removable Prosthodontics. Philadelphia, 1969, W. B. Saunders Company, p 247.
ARTICLES
TO APPEAR IN FUTURE
ISSUES
Construction of orbital prostheses using the silicone pattern technique K. Oral, D.D.S., M.S.D.,
Ph.D., I. Zini, and M. A. Aramany,
D.M.D.,
MS.
A method of assessing the clinical solubility and disintegration cements John W. Osborne, D.D.S., M.S.D., Marjorie L. Swartz, MS., M.S.D., Ralph W. Phillips, DSc., and Elliot N. Gale, Ph.D.
Single-visit
of luting
Charles j. Goodacre,
D.D.S.,
hollow obturators for edentulous patients
Stephen M. Parel, D.D.S., and Henry LaFuente
~iscoeIastic properties of the periodontal D. C. A. Picton, Ph.D., B.D.S., F.D.S.R.C.S.,
ligament and mucous membrane
and D. J. Wills, MSc.,
Ph.D.
Performance criteria in preclinical denture prosthodontics Michael Razzoog, D.D.S., M.S., M.P.H., Jeffrey L. Shotwell, and Brien R. Lang, D.D.S., M.S.
D.D.S., M.S.,
basic wax contouring for complete dentures Robert P. Renner, D.D.S., and Richard
W. Blakeslee
Computer-graphic representation of mandibular movements in three dimensions. Part II. The sagittal and frontal planes William M.
H. Roedema,
K. Dever.
D.D.S., M.S., John G. Knapp,
D.D.S., M.S.. Judson
Spencer,
M.S.,
and
B.S.
Layered silicone rubber technique for flasking removable partial dentures Forrest R. Scandrett,
THE JOURNAL
OF PROSTHETIC
D.D.S., M.S., Jay G. Hanson, D.D.S., and Richard
DENTISTRY
L. Unsicker
229
P
roperly fitting removable partial denture frameworks-in the mouth is usually done using a chloroform-gold rough mixture or a disclosing wax. Many authors also suggest relating the framework to the master cast prior to fitting it in the mouth.‘-3-This time-saving step of properly fitting the tooth- and tissue-contacting surfaces of the framework needs more emphasis. The undersides (tooth surfaces) of rests, clasps, and major and minor connectors should be finished a8 smooth as those surfaces that they approximate to obtain a uniform fit. The inability to adapt the framework precisely to the master caSt or the mouth can be attributed to several factors. Some of these are: (1) The surface of the master cast is more coarse than the polished abutment tooth. (2) The irregular surface of the refractory case. imparts a rough finish to the casting. (3) In the chrome-cobalt technique the casting is dimensionally smaller than the wax pattern.? This article describe8 a laboratory finishing technique that, if carefully done, greatly reduces the amount of chairside time necessary to adapt to a framework and produces a well-fitting removable partial denture. TECHNIQUE 1. Duplicate the master cast prior to blockout, and remove the stone above the retentive parts of the clasps. 2. Remove the sprue button and the flash after recovery of the casting using appropriate disks, burs, and stones (Fig. 1). The opinions or assertions herein are the private views of the author and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. *Lieutenant Colonel, DC, USA; Chief, Maxillofacial Prosthetics. TPersonal Communications: Murphy, P.W., 1974.
THEJOURNAL OF PIZOSTHETICDENTISTRY
Fig. 1. Flash is removed using a pointed stone in a highspeed’ lathe. 3. Under magnif&tion, carefully inspect the underside of the casting for bubbles or irregularities (Fig. 2). 4. Remove these irregularities with small pointed stones or burs and electropolish. 5. Spray a thin layer of zinc stearate disclosing powder* on the underside of the casting. 6. Place the framework on the duplicate cast and seat it until resistance is felt, using care so as not to abrade the cast. 7. Remove the framework and inspect the underside for spots of interference demonstrated in the powder. Relieve these spots carefully and repeat this procedure until the casting goes to place without abrading the cast (Figs. 3 and 4). Inspection of all surfaces of tooth contact on the framework will reveal that these areas are still extremely rough (Fig. 5). 8. Smooth the rough surfaces by burnishing with a small pointed stone and a rubber point, being *Indicating
Spray,
Ney Co., Bloomfield,
Conn
227
Fig. 5. The coarse appearance al of interferences.
of framework
Fig. 3. Stone superior to retentive surfaces is removed on the duplicate cast.
Fig. 6. The tooth-contacting surfaces appear prior to trial in the mouth.
Fig. 4. The casting is completely cast.
Fig. 7. The framework after minimal properly positioned in the mouth.
seated on the duplicate
careful not to change the contours. Buff lightly to a high shine (Fig. 6). 9. Place the framework on the master cast. If the stone above the retentive portions of the clasps is removed, the framework should fully seat without abrading the cast. If not, steps No. 5 through 8 may be repeated.
228
after rem
as they
should
adjustments
is
SUMMARY A technique has been described for fitting a removable partial denture framework to the master cast prior to adapting it in the mouth. Emphasis should be placed on maintaining the original contour of the framework throughout the procedure. The amount of metal removed should be only that
AUGUST
1978
VOLUME
40
NUMBER
2
FITTING
REMOVABLE
PARTIAL
DENTURE
FRAMEWORKS
necessary to seat the casting on the master cast without abrading the stone. When finishing the tooth-contacting surfaces of the casting, very light pressure should be used to burnish the rough surfaces, not reduce them. If these steps are accomplished carefully in the laboratory, the dentist should be able to fit the framework in the mouth in a minimum of time (Fig. 7).
2.
3.
requests
Reprint Da.
WILLIAM
CHIEF,
to: D. Gnu
MAXILLOPACIAI.
WALTER
REFERENCES 1.
Applegate, 0. C.: Essentials of Removable Partial Denture Prosthesis, ed 3. Philadelphia, 1966, W. B. Saunders Company, p 361. Henderson, D., and Steffel, V.: McCracken’s Partial Denture Construction, ed 4. St. Louis, 197 1. The C. V. Mosby Company, pp 364, 400.
REED
WASHINGTON,
ARMY
PROSTHETICS MEDICAL
SERVICE
CENTER
D. C. 20012
Dykema, R. W., Cunningham, D. M., and Johnson, J. F.: Modern Practice in Removable Prosthodontics. Philadelphia, 1969, W. B. Saunders Company, p 247.
ARTICLES
TO APPEAR IN FUTURE
ISSUES
Construction of orbital prostheses using the silicone pattern technique K. Oral, D.D.S., M.S.D.,
Ph.D., I. Zini, and M. A. Aramany,
D.M.D.,
MS.
A method of assessing the clinical solubility and disintegration cements John W. Osborne, D.D.S., M.S.D., Marjorie L. Swartz, MS., M.S.D., Ralph W. Phillips, DSc., and Elliot N. Gale, Ph.D.
Single-visit
of luting
Charles j. Goodacre,
D.D.S.,
hollow obturators for edentulous patients
Stephen M. Parel, D.D.S., and Henry LaFuente
~iscoeIastic properties of the periodontal D. C. A. Picton, Ph.D., B.D.S., F.D.S.R.C.S.,
ligament and mucous membrane
and D. J. Wills, MSc.,
Ph.D.
Performance criteria in preclinical denture prosthodontics Michael Razzoog, D.D.S., M.S., M.P.H., Jeffrey L. Shotwell, and Brien R. Lang, D.D.S., M.S.
D.D.S., M.S.,
basic wax contouring for complete dentures Robert P. Renner, D.D.S., and Richard
W. Blakeslee
Computer-graphic representation of mandibular movements in three dimensions. Part II. The sagittal and frontal planes William M.
H. Roedema,
K. Dever.
D.D.S., M.S., John G. Knapp,
D.D.S., M.S.. Judson
Spencer,
M.S.,
and
B.S.
Layered silicone rubber technique for flasking removable partial dentures Forrest R. Scandrett,
THE JOURNAL
OF PROSTHETIC
D.D.S., M.S., Jay G. Hanson, D.D.S., and Richard
DENTISTRY
L. Unsicker
229