n improved Fisher,
technique DMD,
MSD,a
for processing
and R. A. Baillie,
CDT,
an overdenture
on
MDTb
Montreal,Quebec,Canada This article shows an altsrnate procedure for making an overdenture on implants. This method helps to eliminate a chairside reline for the dentist by directly incorporating the clips into the heat-cured acrylic resin. The procedure is divided into three main sections. The first section deals with the impressions, casts, and records. The second section relates to the making of the bar, and the third section shows the assembling of the clips. (J PROSTHET DENT 1992;68:377-9.)
mplants are becoming more commonly used in dental practice. The technique outlined in this article is for the edentulous arch with implants, where an overdenture is required. Many overdentures on implants require some form of a bar using either a precision or semiprecisionattachment system. One of the most commonmethodsof fastening these attachments to the overdenture is by using the autopolymerizing acrylic resin intraorally. The following technique will save chair time at the delivery appointment for the overdenture on implants. The procedure for making a mandibular denture will illustrate the technique.
Impressions,
casts, and records
. . The final impressionmust have all the requirementsof ? a good, final complete denture impression, plus an
aProsthodontist, Private Practice,Montreal. bCertifiedDentalTechnician,Private Practice,Montreal. 16/X/37636
THE JOURNAL
accurate impressionof the abutments (Fig. 1). The impressionmaterial of choice is polyether or vinyl polysiloxane. 2. With the abutment replicas in place, pour the impression in stone (Vel-mix, Sybron/Kerr, Romulus, Mich.) (Fig. 2). 3. Make an acrylic resin baseplatewith the sprinkle-on technique, and attach a wax occlusion rim. The baseplate should be attached to the abutment replicaswith the modified impressioncopings (Fig. 3). 4. Make centric relation recordsand mount the castsin an articulator in the usual manner. Index the cast sothat it can be remounted in the articulator after the overdenture is processed. 5. Arrange the artificial teeth and wax them for a try-in to determine whether the esthetics and phonetics are acceptable to the patient. Making
the Bar
1. Make a matrix over the teeth to permit the designof the bar to be related to the position of the teeth after the wax hasbeeneliminated (Fig. 4). We prefer a manufactured bar instead of a cast bar, becausethe quality and integ-
Fig.
1. Final elastomerimpressionwith abutment replicas in place.
Fig.
2. Stone cast with modified impressioncopingson abutment replicas.
OF PROSTHETIC
DENTISTRY
377
FISHER
AND
BAILLIE
Fig. 3. Baseplate attached firmly to modified impression copings with acrylic resin. %ig. 4. Lingual view of stone index indicating relationship of teeth to Dolder bar. Fig. 5. Dolder bar fits precisely on abutment replicas and retentive portions of clips are blocked out with wax. Fig. 6. Part of index with denture teeth in place held in position on master cast to be certain teeth clear. Stone block-out under and around Dolder bar and metal clips to eliminate undercuts. Only wax block-out of retentive portion of clips is exposed. Fig. 7. Flask separated and wax eliminated. Stone lodged in or blocking holes in retentive arms of clips must be removed before tinfoil substitute is applied to stone. Fig. 8. Clips processed in overdenture when it is packed and processed. Amount of stone block-out around Dolder bar and clips may be varied to fit given situation.
rity of a manufactured bar cannot dental laboratory. 2. After the bar is soldered together, the abutments in the mouth. This tant. The bar must fit exactly on the 378
be duplicated
in a
it must be fitted on step is very imporimplant abutments.
When the bar does not fit, it must be sectioned and fastened together in the mouth with autocuring acrylic resin. Then the bar must be invested and resoldered. Sometimes it is possible to retrofit the abutment replica to the existing cast, provided more than two abutments AUGUST
1992
VOLUME
68
NUMBER
2
PROCESSING
AN OVERDENTURE
ON IMPLANTS
are involved and only one coping does not fit properly on the abutments in the mouth.
Assembling
the clips
1. When the bar fits, adjust the length of the Dolder bar clips (Cendres & Metaux, §A, Biel-Bienne, Suisse) to the various sections of the bar, and leave them in place. 2. Block out the retentive portions of the clips with wax (Fig. 5). 3. Use Vel-mix dental stone to block out all undercuts under the metal bar and cover all of the metal except the retentive portions of the clips that are covered with wax (Fig. 6). An alternative block-out material is Flexistone (Regneri & Co. KG, Karlsruhe, Germany). 4. Use the previously made matrix to realign the teeth (Figs. 4 and 6). 5. Flask the denture, eliminate the wax, and clean thoroughly (Fig. 7). 6. With a scalpel blade, trim any stone lodged around or under the retentive arms of a clip, which are to be anchored in the acrylic resin (Fig. 7). 7. Coat the cast and all stone with tinfoil substitute. All exposed metal should be free of tinfoil substitute.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
8. Pack and process the heat-cured acrylic resin in the usual manner. 9. Deflask, but do not remove the denture from the cast. 10. Remount the cast and denture in the articulator and make occlusal adjustments. 11. Separate the overdenture from the cast and remove all stone residue (Fig. 8). 12. Retrieve the bar from the cast. 13. Trim and polish the overdenture and it is ready for the patient (Fig. 8). Because the attachments are processed at the same time as the overdenture, considerable chair time will be saved at the final appointment and the processed resin will not discolor around the attachments, which occurs occasionally with autopolymerizing resin when the attachments are processed after the denture is completed. Reprint
requests
to:
DR. RONALD FISHER 552 BERWICK AVE. MONTREAL, QUEBEC H3R 2A2 CANADA
379
technique DMD,
MSD,a
for processing
and R. A. Baillie,
CDT,
an overdenture
on
MDTb
Montreal,Quebec,Canada This article shows an altsrnate procedure for making an overdenture on implants. This method helps to eliminate a chairside reline for the dentist by directly incorporating the clips into the heat-cured acrylic resin. The procedure is divided into three main sections. The first section deals with the impressions, casts, and records. The second section relates to the making of the bar, and the third section shows the assembling of the clips. (J PROSTHET DENT 1992;68:377-9.)
mplants are becoming more commonly used in dental practice. The technique outlined in this article is for the edentulous arch with implants, where an overdenture is required. Many overdentures on implants require some form of a bar using either a precision or semiprecisionattachment system. One of the most commonmethodsof fastening these attachments to the overdenture is by using the autopolymerizing acrylic resin intraorally. The following technique will save chair time at the delivery appointment for the overdenture on implants. The procedure for making a mandibular denture will illustrate the technique.
Impressions,
casts, and records
. . The final impressionmust have all the requirementsof ? a good, final complete denture impression, plus an
aProsthodontist, Private Practice,Montreal. bCertifiedDentalTechnician,Private Practice,Montreal. 16/X/37636
THE JOURNAL
accurate impressionof the abutments (Fig. 1). The impressionmaterial of choice is polyether or vinyl polysiloxane. 2. With the abutment replicas in place, pour the impression in stone (Vel-mix, Sybron/Kerr, Romulus, Mich.) (Fig. 2). 3. Make an acrylic resin baseplatewith the sprinkle-on technique, and attach a wax occlusion rim. The baseplate should be attached to the abutment replicaswith the modified impressioncopings (Fig. 3). 4. Make centric relation recordsand mount the castsin an articulator in the usual manner. Index the cast sothat it can be remounted in the articulator after the overdenture is processed. 5. Arrange the artificial teeth and wax them for a try-in to determine whether the esthetics and phonetics are acceptable to the patient. Making
the Bar
1. Make a matrix over the teeth to permit the designof the bar to be related to the position of the teeth after the wax hasbeeneliminated (Fig. 4). We prefer a manufactured bar instead of a cast bar, becausethe quality and integ-
Fig.
1. Final elastomerimpressionwith abutment replicas in place.
Fig.
2. Stone cast with modified impressioncopingson abutment replicas.
OF PROSTHETIC
DENTISTRY
377
FISHER
AND
BAILLIE
Fig. 3. Baseplate attached firmly to modified impression copings with acrylic resin. %ig. 4. Lingual view of stone index indicating relationship of teeth to Dolder bar. Fig. 5. Dolder bar fits precisely on abutment replicas and retentive portions of clips are blocked out with wax. Fig. 6. Part of index with denture teeth in place held in position on master cast to be certain teeth clear. Stone block-out under and around Dolder bar and metal clips to eliminate undercuts. Only wax block-out of retentive portion of clips is exposed. Fig. 7. Flask separated and wax eliminated. Stone lodged in or blocking holes in retentive arms of clips must be removed before tinfoil substitute is applied to stone. Fig. 8. Clips processed in overdenture when it is packed and processed. Amount of stone block-out around Dolder bar and clips may be varied to fit given situation.
rity of a manufactured bar cannot dental laboratory. 2. After the bar is soldered together, the abutments in the mouth. This tant. The bar must fit exactly on the 378
be duplicated
in a
it must be fitted on step is very imporimplant abutments.
When the bar does not fit, it must be sectioned and fastened together in the mouth with autocuring acrylic resin. Then the bar must be invested and resoldered. Sometimes it is possible to retrofit the abutment replica to the existing cast, provided more than two abutments AUGUST
1992
VOLUME
68
NUMBER
2
PROCESSING
AN OVERDENTURE
ON IMPLANTS
are involved and only one coping does not fit properly on the abutments in the mouth.
Assembling
the clips
1. When the bar fits, adjust the length of the Dolder bar clips (Cendres & Metaux, §A, Biel-Bienne, Suisse) to the various sections of the bar, and leave them in place. 2. Block out the retentive portions of the clips with wax (Fig. 5). 3. Use Vel-mix dental stone to block out all undercuts under the metal bar and cover all of the metal except the retentive portions of the clips that are covered with wax (Fig. 6). An alternative block-out material is Flexistone (Regneri & Co. KG, Karlsruhe, Germany). 4. Use the previously made matrix to realign the teeth (Figs. 4 and 6). 5. Flask the denture, eliminate the wax, and clean thoroughly (Fig. 7). 6. With a scalpel blade, trim any stone lodged around or under the retentive arms of a clip, which are to be anchored in the acrylic resin (Fig. 7). 7. Coat the cast and all stone with tinfoil substitute. All exposed metal should be free of tinfoil substitute.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
8. Pack and process the heat-cured acrylic resin in the usual manner. 9. Deflask, but do not remove the denture from the cast. 10. Remount the cast and denture in the articulator and make occlusal adjustments. 11. Separate the overdenture from the cast and remove all stone residue (Fig. 8). 12. Retrieve the bar from the cast. 13. Trim and polish the overdenture and it is ready for the patient (Fig. 8). Because the attachments are processed at the same time as the overdenture, considerable chair time will be saved at the final appointment and the processed resin will not discolor around the attachments, which occurs occasionally with autopolymerizing resin when the attachments are processed after the denture is completed. Reprint
requests
to:
DR. RONALD FISHER 552 BERWICK AVE. MONTREAL, QUEBEC H3R 2A2 CANADA
379
