ade from a visible oft liners Michael
L. Huband,
Medical
College of Virginia
light-cured
resin for processing
BS, DDP School of Dentistry,
Richmond,
Va.
When soft lining materials are used in complete dentures it is important to control their thickness and increase the probability of their staying in the denture base. A spacer made of light-curing denture base material makes it possible to do both of these things. The denture base resin is packed against the hard light-cured spacer and can be partially cured. The cured spacer will not flow or be displaced and can be easily removed to allow an even space for packing the soft lining material. (J PFK?~TI&T DENT 1992;68:542-4.)
oft liners for d.entures have been suggested for treating patients with irritation to the denture bearing mucosa, extensive soft tissue or bony undercuts, and congenital or acquired defects of the pa1ate.l Clinical experience shows a high degree of tissue tolerance for these materials and patient acceptance.2 Processing the soft liners requires skill and close attention to detail, because the life of a soft liner is related to the processing procedure and the manner in which the patient cares for the prosthesis.3 Two basic methods are often suggested for processing soft lining materials. One is the use of a spacer during trial packing of the acrylic resin or completing the denture, then the use of a reline procedure? Spacers are made of wax, tinfoil, silicone, or vacuumed forms and are used to create a space between the cast and denture base during trial packing of the acrylic resin. The spacer is discarded, the soft liner is packed, and the materials are cured. This can be done in a single laboratory procedure. In this method it is possible to displace the uncured materials with unpredictable results. In the other method, the denture is made first, the tissue surface of the denture is relieved, and a new impression is made in the denture. The denture is flasked and the impression material is replaced with soft lining material.4, 5 This method permits packing and processing the soft lining material against a cured base, resulting in greater control over the dimensions of the denture base and soft liner. However, both chair and laboratory time are increased when this method is used, and a delay in delivery of the prosthesis to the patient is possible.
spacer that is quickly and easily made; (2) the use of economical, familiar, and readily available materials; (3) a procedure for measuring and controlling the dimensions of the spacer, denture base, and soft liner; (4) the exclusion of materials, such as waxes and indicating sprays, that may contaminate the mold and interfere with bonding at the materials’ interface; (5) allowance for inspection of the clearance between the spacer, denture teeth, and mold; (6) a firm denture base to pack and process the soft liner against; and (7) a minimum number of laboratory procedures. A spacer made from Triad visible light-cured resin (Dentsply International, Inc., York, Pa.) has most of these features.
DISCUSSION
PROCEDURE
A procedure that combines the best qualities of both methods and reduces their shortcomings is desirable. The requirements of an ideal spacing procedure include (1) a aDoctoral student. IQ/l/38626
542
Fig. 1. putty.
Severe undercuts blocked out with impression
1. Set the denture teeth in wax. Plastic teeth will strengthen the denture base after it is processed.‘j When there is limited interocclusal distance, reduce the denture teeth to allow for more thickness of the soft lining material and denture base material. Generally 4 mm to 6 mm of clearance between the artificial denture
SEPTEMBER
1992
VOLUME
68
NUMBER
3
SPACER
MADE
OF LIGHT-CURED
Fig. 2. Measuring probe.
RESIN
the dimensions of uncured spacer with
Fig. 3. Imprint of a denture tooth on uncured spacer indicates need to reduce the denture tooth (arrow).
2. 3. 4.
5.
6.
THE
teeth and the edentulous ridge is recommended for an adequate bulk of materials. Festoon, flask, and boil out as usual. Paint the cast with a suitable separating medium. Block out undercuts with Reprosil impression putty (L. D. Caulk Co., Div. of Dentsply International, Inc., Milford, Del.) to reduce the chance of fracturing the cast during removal of the spacer in subsequent steps (Fig. 1). Adapt a sheet of Triad VLC resin material to the cast. The spacer should be 2 mm to 3 mm in height over the crest of the ridge and taper slightly as it approaches the borders.6 Use a periodontal probe to measure the thickness of the spacer in several representative areas (Fig. 2). Trial close the flask, then open and inspect for clearance of the spacer. If imprints of the denture teeth or other interferences are observed on the spacer (Fig. 3), reduce the spacer or denture teeth or both. Recontour the spacer material in the region of the interference and repeat the trial closure.
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig.
4. Relieving
spacer where denture base is too thin.
Fig. 5. Completed denture with smooth, even butt joint between soft liner and denture base (arrows).
7. Paint the spacer with an air barrier and cure with a visible light source for 1 to 2 minutes. 8. Trial pack the acrylic resin with the spacer and a separating sheet in place. Measure the thickness of the packed denture base in several spots with a periodontal probe. For sufficient strength of the prosthesis, a minimum of 3 mm of acrylic resin over the crest of the ridge is recommended.5 Relieve the spacer with a bur wherever the denture base is too thin and repeat trial packing (Fig. 4). 9. With the spacer and a separating sheet in place, clamp the flask and place it in a water bath at 165O F for 30 to 45 minutes.7 10. Remove the flask from the water bath and allow it to air cool. 11. Open the flask and remove the separating sheet, spacer, and impression putty from the cast. Heat the spacer with the flame of an alcohol torch to soften it and prevent damage to the cast. 12. Refine the borders of the partially cured denture base with a sharp scalpel.
543
HUBAND
15. Clean the cast and apply
an appropriate
separating
medium. 14. Pack and process the soft lining material as directed by the manufacturer. 15. Deflask, finish, and polish the denture. Rotary instruments should turn from the soft liner toward the denture base to reduce the chancels of tearing the soft lining materials (Fig. 5).
SUMMARY Using a spacer made from a visible light-cured resin has several advantages over traditional methods. The disadvantages of additional cost of the specific materials and visible light source used in this procedure may be overcome as these materials and equipment become standard armamentarium in the practice of dentistry. Thanks to J. Daniel Huband, DA, and Albert L. Huband, DDS, FAGD, for their assistance.
544
REFERENCES 1. Craig Robert G, ed. Restorative dental materials. 7th ed. St Louis: CV Mosby, 1985;496. 2. Hickey JC, Zarb GA, Bolender CL. Boucher’s prosthodontic treatment for edentulous patients. 9th ed. St Louis: CV Moshy, 1985;17. 3. Laney WR. Processed resilient denture liner. Dent CIin North Am 1970;14:538-50. 4. Bolouri A. A silicone rubber spacer for processed resilient liner in removable prosthodontics. J PROSTHET DENT 1987;57:118. 5. Morrow RM, Rudd D, Rhoads JE. Dental laboratory procedures. ~011. Complete dentures. St Louis: CV Mosby, 1986;451. 6. Winkle1 S. Essential of complete denture prosthodontics. 2nd ed. Littleton, Mass: PSG Publishing, Inc, 1988;314. 7. Package insert for Novas soft denture liner. Hygenic Akron, Ohio: Corporation, 1989. Reprint requests to: DR. MICHAEL L. HUBAND 6513 HAGUEMAN DRIVE RICHMOND. VA 23225
Jr.,
SEPTEMBER
1992
VOLUME
68
NUMBER
3
L. Huband,
Medical
College of Virginia
light-cured
resin for processing
BS, DDP School of Dentistry,
Richmond,
Va.
When soft lining materials are used in complete dentures it is important to control their thickness and increase the probability of their staying in the denture base. A spacer made of light-curing denture base material makes it possible to do both of these things. The denture base resin is packed against the hard light-cured spacer and can be partially cured. The cured spacer will not flow or be displaced and can be easily removed to allow an even space for packing the soft lining material. (J PFK?~TI&T DENT 1992;68:542-4.)
oft liners for d.entures have been suggested for treating patients with irritation to the denture bearing mucosa, extensive soft tissue or bony undercuts, and congenital or acquired defects of the pa1ate.l Clinical experience shows a high degree of tissue tolerance for these materials and patient acceptance.2 Processing the soft liners requires skill and close attention to detail, because the life of a soft liner is related to the processing procedure and the manner in which the patient cares for the prosthesis.3 Two basic methods are often suggested for processing soft lining materials. One is the use of a spacer during trial packing of the acrylic resin or completing the denture, then the use of a reline procedure? Spacers are made of wax, tinfoil, silicone, or vacuumed forms and are used to create a space between the cast and denture base during trial packing of the acrylic resin. The spacer is discarded, the soft liner is packed, and the materials are cured. This can be done in a single laboratory procedure. In this method it is possible to displace the uncured materials with unpredictable results. In the other method, the denture is made first, the tissue surface of the denture is relieved, and a new impression is made in the denture. The denture is flasked and the impression material is replaced with soft lining material.4, 5 This method permits packing and processing the soft lining material against a cured base, resulting in greater control over the dimensions of the denture base and soft liner. However, both chair and laboratory time are increased when this method is used, and a delay in delivery of the prosthesis to the patient is possible.
spacer that is quickly and easily made; (2) the use of economical, familiar, and readily available materials; (3) a procedure for measuring and controlling the dimensions of the spacer, denture base, and soft liner; (4) the exclusion of materials, such as waxes and indicating sprays, that may contaminate the mold and interfere with bonding at the materials’ interface; (5) allowance for inspection of the clearance between the spacer, denture teeth, and mold; (6) a firm denture base to pack and process the soft liner against; and (7) a minimum number of laboratory procedures. A spacer made from Triad visible light-cured resin (Dentsply International, Inc., York, Pa.) has most of these features.
DISCUSSION
PROCEDURE
A procedure that combines the best qualities of both methods and reduces their shortcomings is desirable. The requirements of an ideal spacing procedure include (1) a aDoctoral student. IQ/l/38626
542
Fig. 1. putty.
Severe undercuts blocked out with impression
1. Set the denture teeth in wax. Plastic teeth will strengthen the denture base after it is processed.‘j When there is limited interocclusal distance, reduce the denture teeth to allow for more thickness of the soft lining material and denture base material. Generally 4 mm to 6 mm of clearance between the artificial denture
SEPTEMBER
1992
VOLUME
68
NUMBER
3
SPACER
MADE
OF LIGHT-CURED
Fig. 2. Measuring probe.
RESIN
the dimensions of uncured spacer with
Fig. 3. Imprint of a denture tooth on uncured spacer indicates need to reduce the denture tooth (arrow).
2. 3. 4.
5.
6.
THE
teeth and the edentulous ridge is recommended for an adequate bulk of materials. Festoon, flask, and boil out as usual. Paint the cast with a suitable separating medium. Block out undercuts with Reprosil impression putty (L. D. Caulk Co., Div. of Dentsply International, Inc., Milford, Del.) to reduce the chance of fracturing the cast during removal of the spacer in subsequent steps (Fig. 1). Adapt a sheet of Triad VLC resin material to the cast. The spacer should be 2 mm to 3 mm in height over the crest of the ridge and taper slightly as it approaches the borders.6 Use a periodontal probe to measure the thickness of the spacer in several representative areas (Fig. 2). Trial close the flask, then open and inspect for clearance of the spacer. If imprints of the denture teeth or other interferences are observed on the spacer (Fig. 3), reduce the spacer or denture teeth or both. Recontour the spacer material in the region of the interference and repeat the trial closure.
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig.
4. Relieving
spacer where denture base is too thin.
Fig. 5. Completed denture with smooth, even butt joint between soft liner and denture base (arrows).
7. Paint the spacer with an air barrier and cure with a visible light source for 1 to 2 minutes. 8. Trial pack the acrylic resin with the spacer and a separating sheet in place. Measure the thickness of the packed denture base in several spots with a periodontal probe. For sufficient strength of the prosthesis, a minimum of 3 mm of acrylic resin over the crest of the ridge is recommended.5 Relieve the spacer with a bur wherever the denture base is too thin and repeat trial packing (Fig. 4). 9. With the spacer and a separating sheet in place, clamp the flask and place it in a water bath at 165O F for 30 to 45 minutes.7 10. Remove the flask from the water bath and allow it to air cool. 11. Open the flask and remove the separating sheet, spacer, and impression putty from the cast. Heat the spacer with the flame of an alcohol torch to soften it and prevent damage to the cast. 12. Refine the borders of the partially cured denture base with a sharp scalpel.
543
HUBAND
15. Clean the cast and apply
an appropriate
separating
medium. 14. Pack and process the soft lining material as directed by the manufacturer. 15. Deflask, finish, and polish the denture. Rotary instruments should turn from the soft liner toward the denture base to reduce the chancels of tearing the soft lining materials (Fig. 5).
SUMMARY Using a spacer made from a visible light-cured resin has several advantages over traditional methods. The disadvantages of additional cost of the specific materials and visible light source used in this procedure may be overcome as these materials and equipment become standard armamentarium in the practice of dentistry. Thanks to J. Daniel Huband, DA, and Albert L. Huband, DDS, FAGD, for their assistance.
544
REFERENCES 1. Craig Robert G, ed. Restorative dental materials. 7th ed. St Louis: CV Mosby, 1985;496. 2. Hickey JC, Zarb GA, Bolender CL. Boucher’s prosthodontic treatment for edentulous patients. 9th ed. St Louis: CV Moshy, 1985;17. 3. Laney WR. Processed resilient denture liner. Dent CIin North Am 1970;14:538-50. 4. Bolouri A. A silicone rubber spacer for processed resilient liner in removable prosthodontics. J PROSTHET DENT 1987;57:118. 5. Morrow RM, Rudd D, Rhoads JE. Dental laboratory procedures. ~011. Complete dentures. St Louis: CV Mosby, 1986;451. 6. Winkle1 S. Essential of complete denture prosthodontics. 2nd ed. Littleton, Mass: PSG Publishing, Inc, 1988;314. 7. Package insert for Novas soft denture liner. Hygenic Akron, Ohio: Corporation, 1989. Reprint requests to: DR. MICHAEL L. HUBAND 6513 HAGUEMAN DRIVE RICHMOND. VA 23225
Jr.,
SEPTEMBER
1992
VOLUME
68
NUMBER
3
