0
ade microwaveable
denture
reline
Robert E. McKinstry, DMD, MDS, MA,a and Ivo Zinib Eye and Ear Hospital, Regional Center for Maxillofacial Prosthetic Rehabilitation; of Pit.tsburgh, School of Dental Medicine, Pittsburgh, Pa.
jig
and University
This article describes a procedure for making a denture reline jig for processing denture base resin in a microwave oven. The jig is intended for use with the newer microwave curing denture base resins. The reline jig is economical to produce and is made from fiberglass liquid resin commonly used in automobile body repairs. The fiberglass liquid resin is strengthened by adding fillers of dental stone and chopped fiberglass strands. (J PROSTHET DENT 1992;67:269-74.)
he relining of a complete denture has been regarded as a compromisetreatment.l It can be a difficult clinical procedure to produce a relined denture that fits satisfactorily without causingchangesin the occlusion.The relining procedure is indicated where denture retention is marginal and the tooth position and occlusal vertical dimensionare satisfactory. The relining of a successfulimmediate denture can serve to preserve the natural tooth position establishedin the denture. The three principal techniquesusedin relining dentures are: (1) the direct intraoral application of autopolymerizing acrylic resin; (2) the indirect method, which usesheatcuring acrylic resin; and (3) the indirect method, which involves curing of autopolymerizing acrylic resin under water in the presence of compressed
air. The disadvantages
of the direct intraoral method are: 1. This method can be unpleasant to the patient. 2. The flow of the material is sluggishand cannot be controlled in contrast to conventional impressionmaterials. 3. The maintenance of a satisfactory occlusionmay be difficult. 4. When the denture is not properly positioned on the first attempt, subsequentcorrection may be difficult. 5, The border thickness and length are not easily controlled. 6. Defects in the tissue surface detail are common. 7. The cured resin may exhibit
unsatisfactory
porosity.
8. The materials are not color-stable. The conventional heat-cured acrylic resin reline method has several disadvantages,
which
include:l
1. Patients must be without their dentures for 1 day or longer.
2. Reheatingthe original denture baseto cure the added acrylic resin may causewarping. 3. The processingchangesin the occlusionare added to the changes in occlusion that occur as a result of the impressionprocedure. The indirect method of denture relining, which involves the curing of autopolymerizing resin under water at 100” F and 20 psi air pressure,also has several deficiencies. 1. The autopolymerizing resin may not be color-stable over time.2 2. The tissuesurface of the relined denture may exhibit porosities.2 3. The transverse strength of the heat-cured resin relined with autopolymerizing resin may be less than the original transverse strength of the heat-cured resin.3 Recently, a microwaveableresin (Acron MC, G.C. International Corp., Scottsdale,Ariz.) hasbeenfound to possess superior dimensional accuracy in comparison with heatcured conventional resins.4This microwaveableresin has alsobeen found to exhibit lessporosity than conventional heat-cured acrylic resins and has satisfactory transverse strength and hardnessproperties.” To make this new microwaveableresin more useful asa reline material, it would be helpful to have a reline jig that can be heated in a microwave oven without damageto the denture, the jig, or microwave oven. This article describesa technique for making a microwaveable denture reline jig which allows successfulpolymerization of the newer microwaveable denture baseresins. The technique of construction of the reline jig is simple and inexpensive.
MATERIALS The following materials are used: 1. Two 314 inch wide plywood strips, 5% inches long cut from a piece of l/2 inch plywood
%rector, Regional Center for Maxillofacial Prosthetic Rehabilitation, Eye and Ear Hospital; Assistant Professor, Department of Prosthodontics, University of Pittsburgh, School of Dental Medicine. bFacial Artist, Regional Center for Maxillofacial Prosthetic Rehabilitation, Eye and Ear Hospital. 10/1/33000
THE JOURNAL
OF PROSTUETIC
I)ENTISTRY
2. Two 314inch wide plywood strips 3 inches long cut from l/2 inch plywood
3. 4. 5. 6.
A No. 2 lead pencil A ruler that has millimeter delineations Two 3 X 5 inch index cards A paper stapler
269
McKINSTRY
SIDE VIEW
AND
ZINI
END VEW I
Fig. 1. Scale drawing of top portion of reline jig (dimensions in millimeters).
length of 65 mm) (Becton Dickenson ford, N.J.) 18. Modeling clay
Co., Ruther-
PROCEDURE Three steps are involved in making a microwaveable denture reline jig: Step 1, making a dental stone pattern of the reline jig; step 2, making a silicone mold of the dental stone pattern; and step 3, making the nut fasteners.
Dental Fig. 2. Dental stone reline jig pattern of top portion of jig. 7. Four suction tubes 10 mm in diameter (two pieces cut 20 mm long and two cut 90 mm long) (Monoject disposable oral evacuators No. 443, Darby Dental Supply Co., Rockville Center, N.Y.) 8. Two 3/8 inch wing nuts 9. Two hex cap bolts 318 inch in diameter and 4% inches long 10. Eight brads 1 inch long 11. Silicone mold material (GI-650 with ultrafast catalyst, Silicones, Inc., High Point, N.C.) 12. One pint of fiberglass liquid resin and catalyst (Permatex Liquid Resin, Loctite Corp., Cleveland, Ohio) commonly available for use in auto body repair shops 13. Fiberglass fibers (832 BB Chopped Strands, Owens Corning Fiberglass Corp., Anderson, S.C.) 14. TWO pieces of window or plate glass approximately 8 inches square 15. A strip of boxing wax 16. Dental artificial stone 17. TWO 60 ml plastic syringes (each barrel cut to a
270
stone
reline
jig patterns
(ste
1. Arrange the four plywood strips to make a form in the shape of a rectangle that will accommodate the length and width dimensions (Fig. 1). Leave the inside corners square. Nail their corners together with brads. 2. Cut from one of the index cards a strip 110 mm long and 20 mm wide. Form the strip to make an ovoid 40 mm long and 25 mm across. Staple the ends of the strip to hold the ends of the ovoid together. 3. Lubricate the two 20 mm long suction tubes with a light coat of petroleum jelly. 4. Make a mix of yellow dental stone and carefully pour it into the space confined by the plywood strips that have been placed on a glass slab or piece of wax paper. 5. Insert the 20 mm long suction tubes and the index card into the soft dental stone to form a pattern conforming to the dimensions shown in Fig. 1. The tubes and index card ovoid should rest firmly against the glass slab. 6. After the stone sets, remove the suction tubes, the index card strip, and the stone ovoid inside the strip. 7. Remove the stone inside the plywood form and use a sharp knife to trim the outer portions of the formed stone. Taper and trim the inside of the ovoid hole in the
FEBRUARY
1992
VOLUME
67
NUMBER
2
MICROWAVEABLE
DENTURE
RELINE
JIG
SIDE WEW
EN0
WV,
Fig. 3. Scale drawing of base portion of reline jig (dimensions in millimeters).
stone form with a knife and bevel the corners of the pattern on a cast trimmer (Figs. 1 and 2). 8. Repeat steps 1 through 7 to form a second dental stone pattern. One of these patterns will be the base of the reline jig and the other will be the top. 9, Lubricate the two 90 mm long suction tubes with a light coat of petroleum jelly. 10. Place two disposable paper drinking cups on the bench with their bottoms up. Place a 90 mm long suction tube through the bottom of each cup vertically and leave at least 62 mm of the suction tube protruding from the bottom of the cup. If necessary, the suction tube may be stabilized by placing wax or modeling clay around it on the inside of the cup. 11. Make a mix of yellow dental stone and pour it into the barrels around the suction tubes. Be certain that the suction tube is centered in the syringe barrel. 12. After the stone sets, remove the plastic syringe barrels and silction tubes from the stone; these stone casts will be bolt patterns. 13. With a knife and fine sandpaper, taper and smooth the stone bolt patterns from about 25 mm in diameter at the bottom to 20 mm at the top and make each bolt 62 mm long (Fig. 3). 14. Soak one of the previously made rectangular dental stone patterns in slurry water for 4 minutes6 remove it, and eliminate any surface liquid. This stone pattern will become the pattern for the base of the reline jig.
THE
JOURSAL
OF PROSTHETIC
DENTISTRY
15. Cut two strips of boxing wax 7 mm wide. Make one strip 260 mm long and the other 200 mm long. Stand the wax on edge on a solid surface and make two rectangular boxes. The long strip will make a box 75 mm long and 55 mm wide. The shorter strip will make a box 60 mm long and 40 mm wide. Make go-degree angles at the corners. Seal the joints with wax. 16. Center each wax rectangle around the tapered side of the ovoid hole in the stone base pattern. Seal the large wax rectangle to the stone base on its outside and seal the smaller wax rectangle to the stone base on its inside. If this is done properly, the wax boxes will form a trough around the ovoid hole about 14 mm wide. 17. Make a mix of yellow stone and pour it into the trough made by the wax rectangle (Fig. 4). Leave the stone with the top of the wax rectangles. 18. After the dental stone has set, remove the boxing wax and rinse the rectangular base stone pattern in slurry water.6 Smooth by trimming, if necessary. 19. Secure the dental stone bolt patterns to the rectangular dental stone base pattern with a mixture of dental stone. Apply the stone mix at the junction of the bolt patterns with the base and blend it into the taper of the stone bolt pattern (Fig. 4). Use the 90 mm long suction tubes to align and stabilize the stone bolt patterns over the holes in the stone base. 20. Trim and smooth both rectangular dental stone patterns and bolt guides with a sharp knife and sandpa-
271
McKINSTRP
Fig. 4. Dental
stone reline jig pattern
of base portion
of
jig.
Fig. 5. Completed
mold of top portion of reline jig patplaster is placed on back of mold for rein-
tern. Dental forcement (arrows).
per. The completed patterns smooth (Figs. 2 and 4).
Making
should
be clean
and
the molds (step 2)
Silicone mold material is used to make a mold of each rectangular dental stone pattern. This material is easy to manipulate and is dimensionally stable. The following steps are used to form a mold of each dental stone pattern. 1. Place each of the two dental stone reline jig patterns on a smooth flat surface. 2. Place the 20 mm long suction tubes in the top of the denture stone reline jig pattern (Fig. 2) and the 90 mm long suction tubes into the holes of the base dental stone reline jig pattern (Fig. 4). 3. Plug the ends of the suction tubes with wax. 4. Mix silicone and ultrafast catalyst according to the manufacturer’s directions. Paint a single coat of silicone over each pattern.
272
AND
ZINI
Fig. 6. Completed mold of base portion of reline jig pattern. Dental plaster is placed on back of mold for reinforcement (arrows).
Fig. 7. Modeling clay is placed around confines of 0.375 inch diameter wing nut to form pattern for nut fasteners for reline jig. 5. Apply a thick (10 mm) final coat of silicone over each pattern. 6. After the final coat of silicone sets, cover the silicone to a depth of approximately 10 mm with dental stone or plaster to serve as a backing for the molds and let it set (Figs. 5 and 6). 7. Remove the dental stone reline jig patterns from the mold. The suction tubes placed in step 2 should come out of the mold with the stone patterns. If they do not, they must be removed.
Making
the nut fasteners
(ste
The nut fasteners will be used to secure both sections of the reline jig. They are made from metal wing nuts and tiberglass. The steps in making these nut fasteners are: 1. Apply modeling clay over and around each of the two 318 inch diameter metal wing nuts to form a pattern as shown in Fig. 7. 2. Lubricate each wing nut clay pattern with a light coat of petroleum jelly.
FEBRUARY
1992
VOLUME
67
NUMBER
2
~~~~RQ~AVEABL~
DENTURE
RELINE
JIG
Fig. 9. Fiberglass mixture is poured into mold and leveled before mold is covered with plate glass.
Fig. 8. Completed modeling clay mold of tener. Note metal wing nut remains in mold rated into final fiberglass nut fastener. Bolt and will be removed after fastener is made
wing nut fasto be incorpois in wing nut in fiberglass.
3. Screw the 4% inch bolt into the wing nut clay pattern. Insert the bolt through the bottom of a disposable drinking cup (Fig. 8). 4. Paint two coats of silicone over the clay pattern. 5. After the final coat of silicone has set, cover the silicone to a depth of 10 mm with dental stone or plaster to form a backing for the mold. 6. Remove the clay from the metal wing nut. The metal wing nut will remain in the mold during final processing with fiberglass (Fig. 8). 7. Repeat the above steps to form a second mold of the metal wing nut clay pattern.
Promssiag
the fiberglass
1. Insert the two bolts (item No. 9 on the materials list) in the mold of the base portion of the reline jig, threaded ends down. The bolts should be inserted to a depth sufficient to allow the heads to be covered with fiberglass (Figs. 6 and 9). 2. Mix 16 ounces of fiberglass liquid resin with the appropriate catalyst, 235 gm of dry dental stone powder, and 23 gm of fiberglass fibers to create a thick slurry.7 3. Fill each of the four molds with the fiberglass mixture.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 10. Completed and assembled microwaveable denture reline jig. Any fiberglass close to end of bolt that might prevent nut fastener from being seated against top of flask should be removed.
Cover the two molds for the top and the base portion of the reline jig with a piece of plate glass (Fig. 9). The molds for the nut fasteners do not need to be covered with glass. 4. Allow 3 hours for the resin to harden and remove the gypsum backing from the silicone molds. 5. Remove the silicone molds from the fiberglass portion of the reline jig. 6. Trim any rough edges or sharp corners with a bur in a dental laboratory handpiece (Fig. IO).
DISCUSSION This microwaveable denture reline jig will permit use of the newer microwaveable denture base acrylic resins to reline dentures and process them in a microwave oven. The technique of relining the denture with the jig is identical to the methods used with conventional metallic denture reline jigs. Smith et a1.l and Sharry8 have described methods of relining dentures using the conventional metallic jigs. The
273
only difference in the technique of relining dentures using the microwaveable denture reline jig is in the processing of the denture base resin in the microwave oven. The time and wattage setting varies for the different types of microwaveable acrylic resins, and the manufacturer’s instructions should be used when relining a denture with these materials. The size of the microwaveable denture reline jig can be varied by changing the size of the dental stone pattern. A larger size jig may be useful for relining obturators and other large intraoral prostheses.
This article describes the procedures for making a denture reline jig to permit processingdenture baseresins in
a microwave oven. The jig is designedfor usewith the newer microwaveabledenture baseresinsthat have shownpromise in terms of better dimensional accuracy of the final denture when compared with the conventional denture baseresin. This technique of making ajig usesinexpensive materials that are commonly obtainable and the technique should not be difficult for a dentist or technician.
Bound
volumes
available
REFERENCES 1. Smith DE, Lord JL, Bolender CL. Complete denture relines with autopolymerizing acrylic resin processed in water under air pressure. J PROSTHETDENT~~~~;~&~O~-~~. 2. Atkinson HF, Harcourt JK. The polymerization of self curing acrylics under air pressure. Aust Dent J 1958;3:183. 3. Chevitarese 0, Craig RG, Peyton FA. The properties of various types of denture base plastics. J PROSTHET DENT 1962;12:711-9. 4. Takamata T, Setcos JC, Phillips RW, et al. Adaptation of acrylic resin dentures as influenced by the activation mode of polymerization. J Am Dent Assoc 1989;119:271-6. 5. AlKhatib B. Microwave polymerization of polymethylmethacrylate denture base resin. MSD Thesis, Indiana University School of Dentistry, Indianapolis, Ind.: 1989:1-80. 6. Morrow RM, Rudd KD, Rhodes JE. Dental laboratory procedurescomplete dentures. 2nd ed. St Louis: CV Mosby Co, 1986:17. 7. McKinstry RE, Zini 1. How to make microwavable denture flasks. J PROSTHET D~1~~1990;63:104-10. 8. Sharry JJ. Complete denture prosthodontics. 2nd ed. New York: McGraw Hill Book Company Inc, 1968:3X-20. Reprint
requests
to:
DR.ROBERT E.MCKINSTRY 5547 BEVERLYPLACE PITTSBURGH,PA~~~O~
to subscribers
Bound volumes of THE JOURNAL OF PROSTHETIC DENTISTRY are available to subscribers (only) for the 1992issuesfrom the publisher at a cost of $55.00 ($68.00international) for Vol. 67 (January-June) and Vol. 68 (July-December). Shipping chargesare included. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 30 days after publication of the last issuein the volume. The binding is durable buckram with the journal name, volume number, and year stampedin gold on the spine. Volumes 65 and 66 are also available. Payment must accompany ali orders. Contact Mosby-Year Book, Inc., Subscription Services, 11830Westline Industrial Drive, St. Louis, MO 63146-3318,USA; phone (800) 3254177, ext. 4351, or (314)453-4351. Subscriptions must be in force to qualify. in place of a regular JOURNAL subscription.
274
Bound
volumes
are not available
FEBRUARY
1992
VOLUME67
NUMBER2
ade microwaveable
denture
reline
Robert E. McKinstry, DMD, MDS, MA,a and Ivo Zinib Eye and Ear Hospital, Regional Center for Maxillofacial Prosthetic Rehabilitation; of Pit.tsburgh, School of Dental Medicine, Pittsburgh, Pa.
jig
and University
This article describes a procedure for making a denture reline jig for processing denture base resin in a microwave oven. The jig is intended for use with the newer microwave curing denture base resins. The reline jig is economical to produce and is made from fiberglass liquid resin commonly used in automobile body repairs. The fiberglass liquid resin is strengthened by adding fillers of dental stone and chopped fiberglass strands. (J PROSTHET DENT 1992;67:269-74.)
he relining of a complete denture has been regarded as a compromisetreatment.l It can be a difficult clinical procedure to produce a relined denture that fits satisfactorily without causingchangesin the occlusion.The relining procedure is indicated where denture retention is marginal and the tooth position and occlusal vertical dimensionare satisfactory. The relining of a successfulimmediate denture can serve to preserve the natural tooth position establishedin the denture. The three principal techniquesusedin relining dentures are: (1) the direct intraoral application of autopolymerizing acrylic resin; (2) the indirect method, which usesheatcuring acrylic resin; and (3) the indirect method, which involves curing of autopolymerizing acrylic resin under water in the presence of compressed
air. The disadvantages
of the direct intraoral method are: 1. This method can be unpleasant to the patient. 2. The flow of the material is sluggishand cannot be controlled in contrast to conventional impressionmaterials. 3. The maintenance of a satisfactory occlusionmay be difficult. 4. When the denture is not properly positioned on the first attempt, subsequentcorrection may be difficult. 5, The border thickness and length are not easily controlled. 6. Defects in the tissue surface detail are common. 7. The cured resin may exhibit
unsatisfactory
porosity.
8. The materials are not color-stable. The conventional heat-cured acrylic resin reline method has several disadvantages,
which
include:l
1. Patients must be without their dentures for 1 day or longer.
2. Reheatingthe original denture baseto cure the added acrylic resin may causewarping. 3. The processingchangesin the occlusionare added to the changes in occlusion that occur as a result of the impressionprocedure. The indirect method of denture relining, which involves the curing of autopolymerizing resin under water at 100” F and 20 psi air pressure,also has several deficiencies. 1. The autopolymerizing resin may not be color-stable over time.2 2. The tissuesurface of the relined denture may exhibit porosities.2 3. The transverse strength of the heat-cured resin relined with autopolymerizing resin may be less than the original transverse strength of the heat-cured resin.3 Recently, a microwaveableresin (Acron MC, G.C. International Corp., Scottsdale,Ariz.) hasbeenfound to possess superior dimensional accuracy in comparison with heatcured conventional resins.4This microwaveableresin has alsobeen found to exhibit lessporosity than conventional heat-cured acrylic resins and has satisfactory transverse strength and hardnessproperties.” To make this new microwaveableresin more useful asa reline material, it would be helpful to have a reline jig that can be heated in a microwave oven without damageto the denture, the jig, or microwave oven. This article describesa technique for making a microwaveable denture reline jig which allows successfulpolymerization of the newer microwaveable denture baseresins. The technique of construction of the reline jig is simple and inexpensive.
MATERIALS The following materials are used: 1. Two 314 inch wide plywood strips, 5% inches long cut from a piece of l/2 inch plywood
%rector, Regional Center for Maxillofacial Prosthetic Rehabilitation, Eye and Ear Hospital; Assistant Professor, Department of Prosthodontics, University of Pittsburgh, School of Dental Medicine. bFacial Artist, Regional Center for Maxillofacial Prosthetic Rehabilitation, Eye and Ear Hospital. 10/1/33000
THE JOURNAL
OF PROSTUETIC
I)ENTISTRY
2. Two 314inch wide plywood strips 3 inches long cut from l/2 inch plywood
3. 4. 5. 6.
A No. 2 lead pencil A ruler that has millimeter delineations Two 3 X 5 inch index cards A paper stapler
269
McKINSTRY
SIDE VIEW
AND
ZINI
END VEW I
Fig. 1. Scale drawing of top portion of reline jig (dimensions in millimeters).
length of 65 mm) (Becton Dickenson ford, N.J.) 18. Modeling clay
Co., Ruther-
PROCEDURE Three steps are involved in making a microwaveable denture reline jig: Step 1, making a dental stone pattern of the reline jig; step 2, making a silicone mold of the dental stone pattern; and step 3, making the nut fasteners.
Dental Fig. 2. Dental stone reline jig pattern of top portion of jig. 7. Four suction tubes 10 mm in diameter (two pieces cut 20 mm long and two cut 90 mm long) (Monoject disposable oral evacuators No. 443, Darby Dental Supply Co., Rockville Center, N.Y.) 8. Two 3/8 inch wing nuts 9. Two hex cap bolts 318 inch in diameter and 4% inches long 10. Eight brads 1 inch long 11. Silicone mold material (GI-650 with ultrafast catalyst, Silicones, Inc., High Point, N.C.) 12. One pint of fiberglass liquid resin and catalyst (Permatex Liquid Resin, Loctite Corp., Cleveland, Ohio) commonly available for use in auto body repair shops 13. Fiberglass fibers (832 BB Chopped Strands, Owens Corning Fiberglass Corp., Anderson, S.C.) 14. TWO pieces of window or plate glass approximately 8 inches square 15. A strip of boxing wax 16. Dental artificial stone 17. TWO 60 ml plastic syringes (each barrel cut to a
270
stone
reline
jig patterns
(ste
1. Arrange the four plywood strips to make a form in the shape of a rectangle that will accommodate the length and width dimensions (Fig. 1). Leave the inside corners square. Nail their corners together with brads. 2. Cut from one of the index cards a strip 110 mm long and 20 mm wide. Form the strip to make an ovoid 40 mm long and 25 mm across. Staple the ends of the strip to hold the ends of the ovoid together. 3. Lubricate the two 20 mm long suction tubes with a light coat of petroleum jelly. 4. Make a mix of yellow dental stone and carefully pour it into the space confined by the plywood strips that have been placed on a glass slab or piece of wax paper. 5. Insert the 20 mm long suction tubes and the index card into the soft dental stone to form a pattern conforming to the dimensions shown in Fig. 1. The tubes and index card ovoid should rest firmly against the glass slab. 6. After the stone sets, remove the suction tubes, the index card strip, and the stone ovoid inside the strip. 7. Remove the stone inside the plywood form and use a sharp knife to trim the outer portions of the formed stone. Taper and trim the inside of the ovoid hole in the
FEBRUARY
1992
VOLUME
67
NUMBER
2
MICROWAVEABLE
DENTURE
RELINE
JIG
SIDE WEW
EN0
WV,
Fig. 3. Scale drawing of base portion of reline jig (dimensions in millimeters).
stone form with a knife and bevel the corners of the pattern on a cast trimmer (Figs. 1 and 2). 8. Repeat steps 1 through 7 to form a second dental stone pattern. One of these patterns will be the base of the reline jig and the other will be the top. 9, Lubricate the two 90 mm long suction tubes with a light coat of petroleum jelly. 10. Place two disposable paper drinking cups on the bench with their bottoms up. Place a 90 mm long suction tube through the bottom of each cup vertically and leave at least 62 mm of the suction tube protruding from the bottom of the cup. If necessary, the suction tube may be stabilized by placing wax or modeling clay around it on the inside of the cup. 11. Make a mix of yellow dental stone and pour it into the barrels around the suction tubes. Be certain that the suction tube is centered in the syringe barrel. 12. After the stone sets, remove the plastic syringe barrels and silction tubes from the stone; these stone casts will be bolt patterns. 13. With a knife and fine sandpaper, taper and smooth the stone bolt patterns from about 25 mm in diameter at the bottom to 20 mm at the top and make each bolt 62 mm long (Fig. 3). 14. Soak one of the previously made rectangular dental stone patterns in slurry water for 4 minutes6 remove it, and eliminate any surface liquid. This stone pattern will become the pattern for the base of the reline jig.
THE
JOURSAL
OF PROSTHETIC
DENTISTRY
15. Cut two strips of boxing wax 7 mm wide. Make one strip 260 mm long and the other 200 mm long. Stand the wax on edge on a solid surface and make two rectangular boxes. The long strip will make a box 75 mm long and 55 mm wide. The shorter strip will make a box 60 mm long and 40 mm wide. Make go-degree angles at the corners. Seal the joints with wax. 16. Center each wax rectangle around the tapered side of the ovoid hole in the stone base pattern. Seal the large wax rectangle to the stone base on its outside and seal the smaller wax rectangle to the stone base on its inside. If this is done properly, the wax boxes will form a trough around the ovoid hole about 14 mm wide. 17. Make a mix of yellow stone and pour it into the trough made by the wax rectangle (Fig. 4). Leave the stone with the top of the wax rectangles. 18. After the dental stone has set, remove the boxing wax and rinse the rectangular base stone pattern in slurry water.6 Smooth by trimming, if necessary. 19. Secure the dental stone bolt patterns to the rectangular dental stone base pattern with a mixture of dental stone. Apply the stone mix at the junction of the bolt patterns with the base and blend it into the taper of the stone bolt pattern (Fig. 4). Use the 90 mm long suction tubes to align and stabilize the stone bolt patterns over the holes in the stone base. 20. Trim and smooth both rectangular dental stone patterns and bolt guides with a sharp knife and sandpa-
271
McKINSTRP
Fig. 4. Dental
stone reline jig pattern
of base portion
of
jig.
Fig. 5. Completed
mold of top portion of reline jig patplaster is placed on back of mold for rein-
tern. Dental forcement (arrows).
per. The completed patterns smooth (Figs. 2 and 4).
Making
should
be clean
and
the molds (step 2)
Silicone mold material is used to make a mold of each rectangular dental stone pattern. This material is easy to manipulate and is dimensionally stable. The following steps are used to form a mold of each dental stone pattern. 1. Place each of the two dental stone reline jig patterns on a smooth flat surface. 2. Place the 20 mm long suction tubes in the top of the denture stone reline jig pattern (Fig. 2) and the 90 mm long suction tubes into the holes of the base dental stone reline jig pattern (Fig. 4). 3. Plug the ends of the suction tubes with wax. 4. Mix silicone and ultrafast catalyst according to the manufacturer’s directions. Paint a single coat of silicone over each pattern.
272
AND
ZINI
Fig. 6. Completed mold of base portion of reline jig pattern. Dental plaster is placed on back of mold for reinforcement (arrows).
Fig. 7. Modeling clay is placed around confines of 0.375 inch diameter wing nut to form pattern for nut fasteners for reline jig. 5. Apply a thick (10 mm) final coat of silicone over each pattern. 6. After the final coat of silicone sets, cover the silicone to a depth of approximately 10 mm with dental stone or plaster to serve as a backing for the molds and let it set (Figs. 5 and 6). 7. Remove the dental stone reline jig patterns from the mold. The suction tubes placed in step 2 should come out of the mold with the stone patterns. If they do not, they must be removed.
Making
the nut fasteners
(ste
The nut fasteners will be used to secure both sections of the reline jig. They are made from metal wing nuts and tiberglass. The steps in making these nut fasteners are: 1. Apply modeling clay over and around each of the two 318 inch diameter metal wing nuts to form a pattern as shown in Fig. 7. 2. Lubricate each wing nut clay pattern with a light coat of petroleum jelly.
FEBRUARY
1992
VOLUME
67
NUMBER
2
~~~~RQ~AVEABL~
DENTURE
RELINE
JIG
Fig. 9. Fiberglass mixture is poured into mold and leveled before mold is covered with plate glass.
Fig. 8. Completed modeling clay mold of tener. Note metal wing nut remains in mold rated into final fiberglass nut fastener. Bolt and will be removed after fastener is made
wing nut fasto be incorpois in wing nut in fiberglass.
3. Screw the 4% inch bolt into the wing nut clay pattern. Insert the bolt through the bottom of a disposable drinking cup (Fig. 8). 4. Paint two coats of silicone over the clay pattern. 5. After the final coat of silicone has set, cover the silicone to a depth of 10 mm with dental stone or plaster to form a backing for the mold. 6. Remove the clay from the metal wing nut. The metal wing nut will remain in the mold during final processing with fiberglass (Fig. 8). 7. Repeat the above steps to form a second mold of the metal wing nut clay pattern.
Promssiag
the fiberglass
1. Insert the two bolts (item No. 9 on the materials list) in the mold of the base portion of the reline jig, threaded ends down. The bolts should be inserted to a depth sufficient to allow the heads to be covered with fiberglass (Figs. 6 and 9). 2. Mix 16 ounces of fiberglass liquid resin with the appropriate catalyst, 235 gm of dry dental stone powder, and 23 gm of fiberglass fibers to create a thick slurry.7 3. Fill each of the four molds with the fiberglass mixture.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Fig. 10. Completed and assembled microwaveable denture reline jig. Any fiberglass close to end of bolt that might prevent nut fastener from being seated against top of flask should be removed.
Cover the two molds for the top and the base portion of the reline jig with a piece of plate glass (Fig. 9). The molds for the nut fasteners do not need to be covered with glass. 4. Allow 3 hours for the resin to harden and remove the gypsum backing from the silicone molds. 5. Remove the silicone molds from the fiberglass portion of the reline jig. 6. Trim any rough edges or sharp corners with a bur in a dental laboratory handpiece (Fig. IO).
DISCUSSION This microwaveable denture reline jig will permit use of the newer microwaveable denture base acrylic resins to reline dentures and process them in a microwave oven. The technique of relining the denture with the jig is identical to the methods used with conventional metallic denture reline jigs. Smith et a1.l and Sharry8 have described methods of relining dentures using the conventional metallic jigs. The
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only difference in the technique of relining dentures using the microwaveable denture reline jig is in the processing of the denture base resin in the microwave oven. The time and wattage setting varies for the different types of microwaveable acrylic resins, and the manufacturer’s instructions should be used when relining a denture with these materials. The size of the microwaveable denture reline jig can be varied by changing the size of the dental stone pattern. A larger size jig may be useful for relining obturators and other large intraoral prostheses.
This article describes the procedures for making a denture reline jig to permit processingdenture baseresins in
a microwave oven. The jig is designedfor usewith the newer microwaveabledenture baseresinsthat have shownpromise in terms of better dimensional accuracy of the final denture when compared with the conventional denture baseresin. This technique of making ajig usesinexpensive materials that are commonly obtainable and the technique should not be difficult for a dentist or technician.
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REFERENCES 1. Smith DE, Lord JL, Bolender CL. Complete denture relines with autopolymerizing acrylic resin processed in water under air pressure. J PROSTHETDENT~~~~;~&~O~-~~. 2. Atkinson HF, Harcourt JK. The polymerization of self curing acrylics under air pressure. Aust Dent J 1958;3:183. 3. Chevitarese 0, Craig RG, Peyton FA. The properties of various types of denture base plastics. J PROSTHET DENT 1962;12:711-9. 4. Takamata T, Setcos JC, Phillips RW, et al. Adaptation of acrylic resin dentures as influenced by the activation mode of polymerization. J Am Dent Assoc 1989;119:271-6. 5. AlKhatib B. Microwave polymerization of polymethylmethacrylate denture base resin. MSD Thesis, Indiana University School of Dentistry, Indianapolis, Ind.: 1989:1-80. 6. Morrow RM, Rudd KD, Rhodes JE. Dental laboratory procedurescomplete dentures. 2nd ed. St Louis: CV Mosby Co, 1986:17. 7. McKinstry RE, Zini 1. How to make microwavable denture flasks. J PROSTHET D~1~~1990;63:104-10. 8. Sharry JJ. Complete denture prosthodontics. 2nd ed. New York: McGraw Hill Book Company Inc, 1968:3X-20. Reprint
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Bound volumes of THE JOURNAL OF PROSTHETIC DENTISTRY are available to subscribers (only) for the 1992issuesfrom the publisher at a cost of $55.00 ($68.00international) for Vol. 67 (January-June) and Vol. 68 (July-December). Shipping chargesare included. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 30 days after publication of the last issuein the volume. The binding is durable buckram with the journal name, volume number, and year stampedin gold on the spine. Volumes 65 and 66 are also available. Payment must accompany ali orders. Contact Mosby-Year Book, Inc., Subscription Services, 11830Westline Industrial Drive, St. Louis, MO 63146-3318,USA; phone (800) 3254177, ext. 4351, or (314)453-4351. Subscriptions must be in force to qualify. in place of a regular JOURNAL subscription.
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FEBRUARY
1992
VOLUME67
NUMBER2
