A template
for
K. Warren, N. J. Capp,
F.D.S., R.C.S.(Edin.), F.D.S., R.C.S.(Edin.),
B.D.S., B.D.S.,
modification
of tooth
preparations
D.R.D., R.C.S.(Edin.),* M.S.(Mich.)**
and
Birmingham Dental Hospital, Birmingham, England Several techniques may be used to assessthe occlusal reduction of crown preparations. These include the useof depth cuts with burs of known diameter and clear matrices madeover either a diagnostic cast or a model of a diagnostic wax-up. However, on occasionswhen inadequate tooth structure is removed, the lack of an interocclusal clearance only becomesapparent after the working castshave been mounted in an articulator (Fig. 1). This article describesa technique that may be used to alter the die and subsequently the tooth to provide more YGacewithout recalling the patient, repreparing the tooth, or remaking the working impressions.It is applicable to restorations made on metal-plated dies. TECHNIQUE
1. Make a well-fitting acrylic resin coping on the die. Use a high-speedhandpiece and tapered bur to reduce the occlusalsurface of the die further through the coping (Fig. 2). Reducethe occlusalsurface in one plane only. 2. When adequate interocclusal clearance has been achieved, remove the coping from the die. Wax the restoration on the modified die, cast, and fit the restoration to the die in the usual manner. 3. At the try-in appointment, remove the temporary res-
*SeniorRegistrar,Departmentof RestorativeDentistry. *“HonorarySeniorClinicalLecturer,Departmentof Conservative Dentistry, EastmanDentalHospital,London,England.
Fig. 2. Occlusalsurface of die is reduced through coping, A, to provide adequate interocclusal distance, B.
3. Acrylic resin coping is placed back on tooth in mouth. Note part of prepared tooth that extends through coping. Fig.
Fig.
1. Note inadequate interocclusal distance between
die and opposingtooth.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
725
TIPS
FROM
OUR
READERS
toration and place the acrylic resin coping on the tooth (Fig. 3). The part of the preparation corresponding to that which was removed on the die will project through the coping. 4. Reduce the tooth until it is level with all edges of the coping (Fig. 4). Try the restoration on the tooth. It should seat as it did on the die. Reprint
requests
to:
DR. K. WARREN BIRMINGHAM DENTAL HOSPITAL ST. CHAD’S QUEENSWAY BIRMINGHAM B4 6NN ENGLAND
Fig. 4. Part of tooth extending through resin coping is reduced until it is level with coping.
Sterile Arash Safati, Tehran, Iran
aluminum
foil
decreases
handpiece
cross
contamination
D.D.S.*
Most professionals are aware of the necessity for sterile conditions during operative procedures. When sterility is not possible, surfaces are disinfected. Autoclaves are used to sterilize instruments, gloves, and certain materials. Sometimes the use of a sterile handpiece may be neglected because it is expensive, will reduce the life of a handpiece, and is time-consuming. In addition, all handpieces are not autoclavable. It is unrealistic to use a separate handpiece for each patient, and merely wiping the handpiece with a disinfecting solution between patients will not suffice. When working on a patient and using an air-water spray, the aerosol sphere may extend more than 30 cm from the source point. This can be proved by wearing a pair of glasses during a procedure. After a few seconds the glasses will be coated with a thin layer of water contaminated with microbes. When the handpiece is not sterilized between patients, sterile gloves are immediately contaminated with a mixture of microbes from the previous and present patient. Aluminum foil as used in the kitchen offers an easy, fast, relatively inexpensive solution to this problem.
handpiece. It is usually desirable to have the foil wide enough to wrap around the handpiece several times. 2. Make enough rectangles so one can be used for each patient scheduled during the day.
PROCEDURE 1. Use a pair of scissors to cut a rectangle of aluminum foil equal to the length of the handpiece measured from the hose attachments to the handpiece to the head where the air-water originates (Fig. 1). Its width must be at least two times greater than the circumference of the
*Graduate Student, Behshti (National) Dental School. 10/4/26174
726
Fig. 1. A, Handpiece. Measure circumference of handpiece at 1 to 2. Measure length of handpiecebetween3 and 4. B, Rectangular piece of aluminum foil cut to measurements.
MAY
lBB1
VOLUME
66
NUMBER
6
for
K. Warren, N. J. Capp,
F.D.S., R.C.S.(Edin.), F.D.S., R.C.S.(Edin.),
B.D.S., B.D.S.,
modification
of tooth
preparations
D.R.D., R.C.S.(Edin.),* M.S.(Mich.)**
and
Birmingham Dental Hospital, Birmingham, England Several techniques may be used to assessthe occlusal reduction of crown preparations. These include the useof depth cuts with burs of known diameter and clear matrices madeover either a diagnostic cast or a model of a diagnostic wax-up. However, on occasionswhen inadequate tooth structure is removed, the lack of an interocclusal clearance only becomesapparent after the working castshave been mounted in an articulator (Fig. 1). This article describesa technique that may be used to alter the die and subsequently the tooth to provide more YGacewithout recalling the patient, repreparing the tooth, or remaking the working impressions.It is applicable to restorations made on metal-plated dies. TECHNIQUE
1. Make a well-fitting acrylic resin coping on the die. Use a high-speedhandpiece and tapered bur to reduce the occlusalsurface of the die further through the coping (Fig. 2). Reducethe occlusalsurface in one plane only. 2. When adequate interocclusal clearance has been achieved, remove the coping from the die. Wax the restoration on the modified die, cast, and fit the restoration to the die in the usual manner. 3. At the try-in appointment, remove the temporary res-
*SeniorRegistrar,Departmentof RestorativeDentistry. *“HonorarySeniorClinicalLecturer,Departmentof Conservative Dentistry, EastmanDentalHospital,London,England.
Fig. 2. Occlusalsurface of die is reduced through coping, A, to provide adequate interocclusal distance, B.
3. Acrylic resin coping is placed back on tooth in mouth. Note part of prepared tooth that extends through coping. Fig.
Fig.
1. Note inadequate interocclusal distance between
die and opposingtooth.
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
725
TIPS
FROM
OUR
READERS
toration and place the acrylic resin coping on the tooth (Fig. 3). The part of the preparation corresponding to that which was removed on the die will project through the coping. 4. Reduce the tooth until it is level with all edges of the coping (Fig. 4). Try the restoration on the tooth. It should seat as it did on the die. Reprint
requests
to:
DR. K. WARREN BIRMINGHAM DENTAL HOSPITAL ST. CHAD’S QUEENSWAY BIRMINGHAM B4 6NN ENGLAND
Fig. 4. Part of tooth extending through resin coping is reduced until it is level with coping.
Sterile Arash Safati, Tehran, Iran
aluminum
foil
decreases
handpiece
cross
contamination
D.D.S.*
Most professionals are aware of the necessity for sterile conditions during operative procedures. When sterility is not possible, surfaces are disinfected. Autoclaves are used to sterilize instruments, gloves, and certain materials. Sometimes the use of a sterile handpiece may be neglected because it is expensive, will reduce the life of a handpiece, and is time-consuming. In addition, all handpieces are not autoclavable. It is unrealistic to use a separate handpiece for each patient, and merely wiping the handpiece with a disinfecting solution between patients will not suffice. When working on a patient and using an air-water spray, the aerosol sphere may extend more than 30 cm from the source point. This can be proved by wearing a pair of glasses during a procedure. After a few seconds the glasses will be coated with a thin layer of water contaminated with microbes. When the handpiece is not sterilized between patients, sterile gloves are immediately contaminated with a mixture of microbes from the previous and present patient. Aluminum foil as used in the kitchen offers an easy, fast, relatively inexpensive solution to this problem.
handpiece. It is usually desirable to have the foil wide enough to wrap around the handpiece several times. 2. Make enough rectangles so one can be used for each patient scheduled during the day.
PROCEDURE 1. Use a pair of scissors to cut a rectangle of aluminum foil equal to the length of the handpiece measured from the hose attachments to the handpiece to the head where the air-water originates (Fig. 1). Its width must be at least two times greater than the circumference of the
*Graduate Student, Behshti (National) Dental School. 10/4/26174
726
Fig. 1. A, Handpiece. Measure circumference of handpiece at 1 to 2. Measure length of handpiecebetween3 and 4. B, Rectangular piece of aluminum foil cut to measurements.
MAY
lBB1
VOLUME
66
NUMBER
6
