A simphd
tmtbd
enddorrtic
treatment
for
constrwlEtiag
a coce
Henry Kahn, D.D.S.,* Irving Fishman, D.D.S., and William F. Mulone, D.D.S., M.S., Ph.D.** Loyola University School of Dentistry, Maywood, Ill.
T
he importance of properly restoring a tooth after endodontic treatment has long been established. Failure may result in tooth fracture and, at times, the actual Ioss of the tooth itself. Much has been written about the dowel, and many different designs exist for placement in the canal of a treated tooth.le3 However, little that is new has been developed to simplify the technique for making the core. Other authors4 previously described the Endowel,? a tapered, impact styrene dowel, which is used with a core portion to be cast and set in the tooth for reinforcement. Either the direct or indirect technique may be used. This report discusses a device that simplifies the fabrication of the core portion by completely eliminating the need for the indirect method while decreasing the chair time required by the direct technique,
SPECIFICATIONS The “core form” device is shaped as an individual tooth after it has been prepared for full coverage. It is made of thin, transparent polyethylene and is available in a wide range of sizes. It is calculated to fit over and closely around the gingival third of an endodontically treated tooth. The form is easily trimmed with scissors. This form is provided with a handle which will bear its identifying number, thus simplifying selection of the proper form from a kit containing many sizes as well as facilitating placement and removal from the prepared tooth (Fig. 1) .
PREPARATtUN OF TttE REtAAtNtNG TOOTH This procedure is divided and preparing the remaining
into two parts---obtaining tooth above the gingiva
*Associate Professor of Endodontics. **Professor and Chairman of Fixed Prosthodontics. tStar
32
Dental
Mfg.
Company,
Inc.,
Conshohocken,
Pa.
dowel room in the filled canal to receive the core form. The
v&hm&317
Core
Fig. 1. The polystyrene trimmed with scissors.
“core
form.”
Fig. 2. A metal dowel is inserted occlusion, is notched and roughened.
The into
construction
handle
the prepared
bears
after
endodontic
the size number.
canal.
The
occlusal
treatment
The
material
portion,
cut
33
is easily short
of
earlier article described a safe method for providing dowel room.4 The length of the dowel should be the same length as the clinical crown. Normally, 3 to 5 mm. of apical filling material should be left undisturbed in the canal. This will not jeopardize the apical seal. High- or low-speed rotary instruments should not be used because of the obvious danger of perforation of the root. Rather, the gutta-percha in the upper portion of the canal can be removed with a heated instrument. This is followed by use of hand reamers to serially widen the canal.5 These reamers should be premeasured to the proper depth with a rubber stop and used with reaming action.6 In the second phase, every effort must be made to conserve as much of the remaining crown as possible. With the help of tapered diamond stones, the remaining bell at and below the gingiva is removed. Next, all undercuts in the pulp chamber are eliminated or, if it is deemed necessary, they should be filled in with cement. Finally, all thin, sharp tips of tooth structure should be flattened. We are now ready for the adaptation of the core form. METHODS
FOR USING
THE CORE
FORM
The actual making and finishing of the core portion can be done more quickly they can be explained. The factor of time savings is only one of the advantages. When the dentist chooses to create a core with a composite resin, the core-form method serves a useful purpose. After the canal is prepared, the proper metal dowel is selected and cut short of the occlusion. That portion which will extend into the pulp chamber should be notched and roughened. Now, cement the prepared dowel permanently (Fig. 2). There may be times when the dentist’s choice will be to use pins only or in combination with the dowel. The diameter of the tooth at the gingival line is taken with a diagnostic loop. This is transferred to the size gauge, and the proper core form is selected. The form is cut to the proper height and trimmed. Mixed composite resin is applied to the inside of the core form around the dowel and poured into the undercuts in the pulp chamber (Fig. 3, A). The core is placed in position over the prepared crown, allowthan
34
Kahn,
Fishman,
J, l’rosthrt. Dent. ,&m,ary. 19x
and Malone
;ntn
pulp chamber. the dowel. (C)
(B) The core form The finished core.
Fig. 4. (A) The prepared placed in the canal and placed over the prepared
is placed
into
position
over
remainder of the crown is lubricated. cut short of occlusion. (C) The core remainder of the crown and pin.
the remainder
of the crown
and
(B) An impact styrene pin is form, filled with casting wax, is
Volume Number
37 1
Core
construction
alter
endodontic
treatment
35
ing the composite resin to polymerize (Fig. 3, B) . The thin core is split with a sharp scaler and removed. Tapered diamond stones are used to remove any flash as well as to finish what little shaping is needed for full coverage (Fig. 3, C) . When a gold dowel and core unit is indicated, the following procedure is used. It is important that there are no undercuts on the walls of the pulp chamber and that the chamber is lubricated (Fig. 4, A). The selected Endowel is placed in position, marked to the proper height, and cut off short of occlusion (Fig. 4, B) . Then the core form is festooned, the dowel covered, and the core form filled with inlay wax. This is placed over the dowel and remainder of the crown. The core form is stopped at the proper height by the dowel (Fig. 4, C) . The core form should not be removed, but rather the handle should be used to remove the core and dowel from the tooth. Outside the mouth, the core form can then be removed from the wax core, and any slight undercuts can be cut away. It can also be re-placed on the tooth and trimmed to shape with a sharp hand instrument. All this can also be done by using dipolymer acrylic resin* in the core form instead of the wax. When the core is finished either in the resin or wax, it is sprued, invested, and cast in gold. ADVANTAGE5
When using a resin as a core directly in the mouth, two methods are generally employed. In one, the core is made by gradually building up the necessary bulk, a time-consuming process. Also, air spaces and a less-condensed core may result, and more time is used in finally shaping the core, which may or may not be adequate because one can only estimate the size. The second method presently in use is to fill a tooth form with the resin, add some around the post, place, and allow to polymerize. After this, the dentist must reduce and shape the resin tooth to the desired size of a core, which will also consume more chair time. A direct pattern for a goId dowel and core may be quickly prepared. Impressions and casts are no longer necessary. The only laboratory work necessary is to sprue, invest, burn out, and cast; this work, of course, is done in either case. One other advantage is that the fixed partial denture or crown impression can be made with the resin dowel and core in place. While the fixed partial denture or crown is being made, the dowel and core unit is also cast, thus saving an appointment. SUMMARY
This report described use of a core form. The principal objectives of the method are (1) the provision of a form of proper size and (2) to allow formation of the core portion of the dowel and core directly in the mouth in much less time than has heretofore been needed.
‘Duralay,
Reliance
Dental
Mfg.
Company,
Chicago,
Ill.
References I. 2.
Weine, Frank, lishers,
F. S.: Endodontic A. L.: In Ingle, pp. 612-623.
Therapy, St. Louis, 1972, The C. V. Mosby Company. J. I., editor: Endodontics, Philadelphia, 1965, Lea & Febiger,
Pub-
36 3. 4. 5. 6.
Kahn, Fishman,
and
.I. 1’,-osthet.
Malone
January.
Dent. l’)i?
Gerstein, H., and Evanson, L.: Precision Posts or Dowels, Ill. Dent. J. 32: 70-73, 1963. Weine, F. S., Kahn, H., Wax, A. H., and Taylor, G. N.: The Use of Standardized Tapered Plastic Pins in Post and Core Fabrication, J. PROSTHET. DENT. 29: 542-548, 1973. Ingle, J. I.: A Standardized Endodontic Technique Utilizing Newly Designed Instruments and Filling Materials, Oral Surg. 14: 83-91, 1961. Gutierrez, J. H., and Garcia, J.: Microscopic and Macroscopic Investigation on Results of Mechanical Preparation of Root Canals, Oral Surg. 25: 108-I 16, 1968. DR. KAHN 1724 GRAND BAHAMA PALM SPRINGS, CALIF.
W. 92262
DR. FISHMAN 25 E. WASHINGTON ST. CHICAGO, ILL. 60602 DR. MALONE LOYOLA UNIVERSITY SCHOOL 2160 S. FIRST AVE. MAYWOOD, ILL. 60153
ARTICLES
OF DENTISTRY
TO APPEAR
IN FUTURE
“Proplast”-coated high-strength stabilization devices Robert
J. Connor,
Infiltration
D.D.S.,
MS.,
D.D.S.,
magnets
and Carl
of a radioactive
Simonides Consani, Stolf, D.D.S., M.S.
Luiz
as potential
W. Svare,
solution
M.S.,
ISSUES
into
Antonio
D.D.S.,
Ph.D.
joined Ruhnke,
silver D.D.S.,
A study of the variability of setting a fully adjustable articulator to a pantographic tracing R. Bruce
Coye,
A clinical John
Prosthodontic pathologist’s Rodger
M.
ama)arrm M.S.,
and
Wolney
gnathologic
D.D.S.
evaluation
W. Dale,
denture
B.D.S.,
of semiprecious D.D.S.,
management view Dalston,
M.D.%,
of the cleft-palate
for dowels and
John
patient:
and cores Moser,
management
Ronald
D.M.D.,
M.S.D.
of the maxtikctomy
MS.,
A speech
Ph.D.
Early rehabilitative P. Desjardins,
alloys F.R.A.C.D.S.,
patient
Ph,D.
Luiz
tmtbd
enddorrtic
treatment
for
constrwlEtiag
a coce
Henry Kahn, D.D.S.,* Irving Fishman, D.D.S., and William F. Mulone, D.D.S., M.S., Ph.D.** Loyola University School of Dentistry, Maywood, Ill.
T
he importance of properly restoring a tooth after endodontic treatment has long been established. Failure may result in tooth fracture and, at times, the actual Ioss of the tooth itself. Much has been written about the dowel, and many different designs exist for placement in the canal of a treated tooth.le3 However, little that is new has been developed to simplify the technique for making the core. Other authors4 previously described the Endowel,? a tapered, impact styrene dowel, which is used with a core portion to be cast and set in the tooth for reinforcement. Either the direct or indirect technique may be used. This report discusses a device that simplifies the fabrication of the core portion by completely eliminating the need for the indirect method while decreasing the chair time required by the direct technique,
SPECIFICATIONS The “core form” device is shaped as an individual tooth after it has been prepared for full coverage. It is made of thin, transparent polyethylene and is available in a wide range of sizes. It is calculated to fit over and closely around the gingival third of an endodontically treated tooth. The form is easily trimmed with scissors. This form is provided with a handle which will bear its identifying number, thus simplifying selection of the proper form from a kit containing many sizes as well as facilitating placement and removal from the prepared tooth (Fig. 1) .
PREPARATtUN OF TttE REtAAtNtNG TOOTH This procedure is divided and preparing the remaining
into two parts---obtaining tooth above the gingiva
*Associate Professor of Endodontics. **Professor and Chairman of Fixed Prosthodontics. tStar
32
Dental
Mfg.
Company,
Inc.,
Conshohocken,
Pa.
dowel room in the filled canal to receive the core form. The
v&hm&317
Core
Fig. 1. The polystyrene trimmed with scissors.
“core
form.”
Fig. 2. A metal dowel is inserted occlusion, is notched and roughened.
The into
construction
handle
the prepared
bears
after
endodontic
the size number.
canal.
The
occlusal
treatment
The
material
portion,
cut
33
is easily short
of
earlier article described a safe method for providing dowel room.4 The length of the dowel should be the same length as the clinical crown. Normally, 3 to 5 mm. of apical filling material should be left undisturbed in the canal. This will not jeopardize the apical seal. High- or low-speed rotary instruments should not be used because of the obvious danger of perforation of the root. Rather, the gutta-percha in the upper portion of the canal can be removed with a heated instrument. This is followed by use of hand reamers to serially widen the canal.5 These reamers should be premeasured to the proper depth with a rubber stop and used with reaming action.6 In the second phase, every effort must be made to conserve as much of the remaining crown as possible. With the help of tapered diamond stones, the remaining bell at and below the gingiva is removed. Next, all undercuts in the pulp chamber are eliminated or, if it is deemed necessary, they should be filled in with cement. Finally, all thin, sharp tips of tooth structure should be flattened. We are now ready for the adaptation of the core form. METHODS
FOR USING
THE CORE
FORM
The actual making and finishing of the core portion can be done more quickly they can be explained. The factor of time savings is only one of the advantages. When the dentist chooses to create a core with a composite resin, the core-form method serves a useful purpose. After the canal is prepared, the proper metal dowel is selected and cut short of the occlusion. That portion which will extend into the pulp chamber should be notched and roughened. Now, cement the prepared dowel permanently (Fig. 2). There may be times when the dentist’s choice will be to use pins only or in combination with the dowel. The diameter of the tooth at the gingival line is taken with a diagnostic loop. This is transferred to the size gauge, and the proper core form is selected. The form is cut to the proper height and trimmed. Mixed composite resin is applied to the inside of the core form around the dowel and poured into the undercuts in the pulp chamber (Fig. 3, A). The core is placed in position over the prepared crown, allowthan
34
Kahn,
Fishman,
J, l’rosthrt. Dent. ,&m,ary. 19x
and Malone
;ntn
pulp chamber. the dowel. (C)
(B) The core form The finished core.
Fig. 4. (A) The prepared placed in the canal and placed over the prepared
is placed
into
position
over
remainder of the crown is lubricated. cut short of occlusion. (C) The core remainder of the crown and pin.
the remainder
of the crown
and
(B) An impact styrene pin is form, filled with casting wax, is
Volume Number
37 1
Core
construction
alter
endodontic
treatment
35
ing the composite resin to polymerize (Fig. 3, B) . The thin core is split with a sharp scaler and removed. Tapered diamond stones are used to remove any flash as well as to finish what little shaping is needed for full coverage (Fig. 3, C) . When a gold dowel and core unit is indicated, the following procedure is used. It is important that there are no undercuts on the walls of the pulp chamber and that the chamber is lubricated (Fig. 4, A). The selected Endowel is placed in position, marked to the proper height, and cut off short of occlusion (Fig. 4, B) . Then the core form is festooned, the dowel covered, and the core form filled with inlay wax. This is placed over the dowel and remainder of the crown. The core form is stopped at the proper height by the dowel (Fig. 4, C) . The core form should not be removed, but rather the handle should be used to remove the core and dowel from the tooth. Outside the mouth, the core form can then be removed from the wax core, and any slight undercuts can be cut away. It can also be re-placed on the tooth and trimmed to shape with a sharp hand instrument. All this can also be done by using dipolymer acrylic resin* in the core form instead of the wax. When the core is finished either in the resin or wax, it is sprued, invested, and cast in gold. ADVANTAGE5
When using a resin as a core directly in the mouth, two methods are generally employed. In one, the core is made by gradually building up the necessary bulk, a time-consuming process. Also, air spaces and a less-condensed core may result, and more time is used in finally shaping the core, which may or may not be adequate because one can only estimate the size. The second method presently in use is to fill a tooth form with the resin, add some around the post, place, and allow to polymerize. After this, the dentist must reduce and shape the resin tooth to the desired size of a core, which will also consume more chair time. A direct pattern for a goId dowel and core may be quickly prepared. Impressions and casts are no longer necessary. The only laboratory work necessary is to sprue, invest, burn out, and cast; this work, of course, is done in either case. One other advantage is that the fixed partial denture or crown impression can be made with the resin dowel and core in place. While the fixed partial denture or crown is being made, the dowel and core unit is also cast, thus saving an appointment. SUMMARY
This report described use of a core form. The principal objectives of the method are (1) the provision of a form of proper size and (2) to allow formation of the core portion of the dowel and core directly in the mouth in much less time than has heretofore been needed.
‘Duralay,
Reliance
Dental
Mfg.
Company,
Chicago,
Ill.
References I. 2.
Weine, Frank, lishers,
F. S.: Endodontic A. L.: In Ingle, pp. 612-623.
Therapy, St. Louis, 1972, The C. V. Mosby Company. J. I., editor: Endodontics, Philadelphia, 1965, Lea & Febiger,
Pub-
36 3. 4. 5. 6.
Kahn, Fishman,
and
.I. 1’,-osthet.
Malone
January.
Dent. l’)i?
Gerstein, H., and Evanson, L.: Precision Posts or Dowels, Ill. Dent. J. 32: 70-73, 1963. Weine, F. S., Kahn, H., Wax, A. H., and Taylor, G. N.: The Use of Standardized Tapered Plastic Pins in Post and Core Fabrication, J. PROSTHET. DENT. 29: 542-548, 1973. Ingle, J. I.: A Standardized Endodontic Technique Utilizing Newly Designed Instruments and Filling Materials, Oral Surg. 14: 83-91, 1961. Gutierrez, J. H., and Garcia, J.: Microscopic and Macroscopic Investigation on Results of Mechanical Preparation of Root Canals, Oral Surg. 25: 108-I 16, 1968. DR. KAHN 1724 GRAND BAHAMA PALM SPRINGS, CALIF.
W. 92262
DR. FISHMAN 25 E. WASHINGTON ST. CHICAGO, ILL. 60602 DR. MALONE LOYOLA UNIVERSITY SCHOOL 2160 S. FIRST AVE. MAYWOOD, ILL. 60153
ARTICLES
OF DENTISTRY
TO APPEAR
IN FUTURE
“Proplast”-coated high-strength stabilization devices Robert
J. Connor,
Infiltration
D.D.S.,
MS.,
D.D.S.,
magnets
and Carl
of a radioactive
Simonides Consani, Stolf, D.D.S., M.S.
Luiz
as potential
W. Svare,
solution
M.S.,
ISSUES
into
Antonio
D.D.S.,
Ph.D.
joined Ruhnke,
silver D.D.S.,
A study of the variability of setting a fully adjustable articulator to a pantographic tracing R. Bruce
Coye,
A clinical John
Prosthodontic pathologist’s Rodger
M.
ama)arrm M.S.,
and
Wolney
gnathologic
D.D.S.
evaluation
W. Dale,
denture
B.D.S.,
of semiprecious D.D.S.,
management view Dalston,
M.D.%,
of the cleft-palate
for dowels and
John
patient:
and cores Moser,
management
Ronald
D.M.D.,
M.S.D.
of the maxtikctomy
MS.,
A speech
Ph.D.
Early rehabilitative P. Desjardins,
alloys F.R.A.C.D.S.,
patient
Ph,D.
Luiz
