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A practical irreversible hydrocolloid impression tray holder
A practical
irreversible
hydrocolloid
Ray A. Walters, D.D.S.* IJniversity of Maryland, Dental School, Baltimore,
*Associate Professor, Department of Removable Prostodontics. 10/4/22645
Fig.
THE
1. Small plastic cup with snap-on lid.
2. Slot cut into lid to depth of flat surface on top.
JOURNAL
OF PROSTHETIC
DENTISTRY
tray
holder
Md.
Proper handling of an alginate (irreversible hydrocolloid) impression after it has been removed from the patient’s mouth is extremely important. Therefore, it is essential to understand and apply several pertinent rules about these impressions to have an acceptable final product. The statement, “What is the most important step you are doing in dentistry,” is often a topic of conversation. The answer is, “The step being done at any given moment.” Since irreversible hydrocolloid impression material is relatively easy to handle, it is often abused. After careful inspection of the impression to determine acceptability as to completeness of anatomic detail and surface quality, the impression should be rinsed, then supported in some fash-
Fig.
impression
ion. Rudd and Dunn1 recommended that the impression never be placed on a bench in such a manner that the irreversible hydrocolloid impression material of the border extension supports the impression. They recommended that the impression be hung by the handle of the tray in a glass jar filled with a solution of potassium sulfate or disinfecting solution. The impression should not be allowed to touch the bottom or sides of the jar. No more than 10 minutes should elapse before the excess liquid is removed from the impression and the first increment of stone is poured.2 The impression tray is once again supported, this time in a case pan, with the handle fitted between two boards 1 x 2 inches in height and width with a small space in between. When the first, increment of stone is set, a base is added. The result is superior to making a cast by the single-pour technique.”
Fig. 3. Slot in lid used to mark place to cut on cup. Cup cut to match lid.
Fig.
4. Stone added to cup to level of cut out.
625
Fig. 5. Two impressions supported in tray holder.
Fig. 6. Holding cup used in laboratory to support impressions while stone is setting.
These holding devices are large and not esthetic, but certainly better than placing the impression in a cabinet drawer slot, where it could be bumped by the dentist or assistant, or placed flat on a counter top. A simple, inexpensive holder can be made that is small, neat, esthetic, and practical because it can be conveniently stored in a drawer in the office when not in use.
place. If the slots do not align exactly, make adjustments. 9. When the slots are properly aligned, use clear adhesive tape or epoxy resin to secure the lid in position so it will not rotate. The cup is small enough to be conveniently stored in an operatory drawer or on a small shelf. After the impressions are made, the tray holder can be used both in the operatory and laboratory (Fig. 6). The tray holder also provides a convenient carrying device for transporting the impressions.
PROCEDURE 1. Purchase a small, round plastic cup with a snap-on lid approximately 3 Y2inches in diameter and 2 inches deep. The cup can be found in any supermarket. A denture cup can also be used (Fig. 1). 2. Use a mounted separating disk to cut two slots in the rim of the lid of the cup approximately the width of an impression tray handle. The slots should be cut only to the flat surface (Fig. 2). 3. Cut two more slots in the lid directly opposite the first two. 4. Connect the two vertical cuts on each site with a horizontal cut to remove the plastic lip section between them (Fig. 2). 5. Place the lid on the cup and mark the extent of the space in the lid on each side of the cup (Fig. 3). 6. Cut and remove the retentive lip of the cup as was done on the lid in steps 2 to 4. 7. Make a mix of yellow dental stone and fill the cup to just below the slot in the base of the cup (Fig. 4). The weight of the stone in the cup prevents tipping when the impression trays are inserted either singularily or in tandem (Fig. 5). 8. Align the slots in the lid and the cup and snap the lid in
626
SUMMARY A small, practical, inexpensive, and esthetic tray-holding device can be made easily for use in the operatory and laboratory. The device, when not in use, can be conveniently stored in a drawer or on a small shelf and is inconspicuous. Several of these devices can be made at one time and strategically located within the office. REFERENCES 1. Rudd KD, Dunn BW. Accurate removable partial dentures. J PROSTHET DENT 1967;18:559-70.
2. Skinner EW, Hobbit NE. A study of the accuracy of bydrocolloid impressions. J PROSTHS~ DENT 1956;6:80-6. 3. Rudd KD, Morrow RM, Bange AA. Accurate casts. J PROETHET DENT 1969;21:545-54.
Reprint requests to: DR. RAY A. WALTERS DENTAL SCHOOL UNMWSI’IT OF MARYLAND BALTIMORE, MD 21201
NOVEMBER
1900
VOLUME
64
NUMBER
5
irreversible
hydrocolloid
Ray A. Walters, D.D.S.* IJniversity of Maryland, Dental School, Baltimore,
*Associate Professor, Department of Removable Prostodontics. 10/4/22645
Fig.
THE
1. Small plastic cup with snap-on lid.
2. Slot cut into lid to depth of flat surface on top.
JOURNAL
OF PROSTHETIC
DENTISTRY
tray
holder
Md.
Proper handling of an alginate (irreversible hydrocolloid) impression after it has been removed from the patient’s mouth is extremely important. Therefore, it is essential to understand and apply several pertinent rules about these impressions to have an acceptable final product. The statement, “What is the most important step you are doing in dentistry,” is often a topic of conversation. The answer is, “The step being done at any given moment.” Since irreversible hydrocolloid impression material is relatively easy to handle, it is often abused. After careful inspection of the impression to determine acceptability as to completeness of anatomic detail and surface quality, the impression should be rinsed, then supported in some fash-
Fig.
impression
ion. Rudd and Dunn1 recommended that the impression never be placed on a bench in such a manner that the irreversible hydrocolloid impression material of the border extension supports the impression. They recommended that the impression be hung by the handle of the tray in a glass jar filled with a solution of potassium sulfate or disinfecting solution. The impression should not be allowed to touch the bottom or sides of the jar. No more than 10 minutes should elapse before the excess liquid is removed from the impression and the first increment of stone is poured.2 The impression tray is once again supported, this time in a case pan, with the handle fitted between two boards 1 x 2 inches in height and width with a small space in between. When the first, increment of stone is set, a base is added. The result is superior to making a cast by the single-pour technique.”
Fig. 3. Slot in lid used to mark place to cut on cup. Cup cut to match lid.
Fig.
4. Stone added to cup to level of cut out.
625
Fig. 5. Two impressions supported in tray holder.
Fig. 6. Holding cup used in laboratory to support impressions while stone is setting.
These holding devices are large and not esthetic, but certainly better than placing the impression in a cabinet drawer slot, where it could be bumped by the dentist or assistant, or placed flat on a counter top. A simple, inexpensive holder can be made that is small, neat, esthetic, and practical because it can be conveniently stored in a drawer in the office when not in use.
place. If the slots do not align exactly, make adjustments. 9. When the slots are properly aligned, use clear adhesive tape or epoxy resin to secure the lid in position so it will not rotate. The cup is small enough to be conveniently stored in an operatory drawer or on a small shelf. After the impressions are made, the tray holder can be used both in the operatory and laboratory (Fig. 6). The tray holder also provides a convenient carrying device for transporting the impressions.
PROCEDURE 1. Purchase a small, round plastic cup with a snap-on lid approximately 3 Y2inches in diameter and 2 inches deep. The cup can be found in any supermarket. A denture cup can also be used (Fig. 1). 2. Use a mounted separating disk to cut two slots in the rim of the lid of the cup approximately the width of an impression tray handle. The slots should be cut only to the flat surface (Fig. 2). 3. Cut two more slots in the lid directly opposite the first two. 4. Connect the two vertical cuts on each site with a horizontal cut to remove the plastic lip section between them (Fig. 2). 5. Place the lid on the cup and mark the extent of the space in the lid on each side of the cup (Fig. 3). 6. Cut and remove the retentive lip of the cup as was done on the lid in steps 2 to 4. 7. Make a mix of yellow dental stone and fill the cup to just below the slot in the base of the cup (Fig. 4). The weight of the stone in the cup prevents tipping when the impression trays are inserted either singularily or in tandem (Fig. 5). 8. Align the slots in the lid and the cup and snap the lid in
626
SUMMARY A small, practical, inexpensive, and esthetic tray-holding device can be made easily for use in the operatory and laboratory. The device, when not in use, can be conveniently stored in a drawer or on a small shelf and is inconspicuous. Several of these devices can be made at one time and strategically located within the office. REFERENCES 1. Rudd KD, Dunn BW. Accurate removable partial dentures. J PROSTHET DENT 1967;18:559-70.
2. Skinner EW, Hobbit NE. A study of the accuracy of bydrocolloid impressions. J PROSTHS~ DENT 1956;6:80-6. 3. Rudd KD, Morrow RM, Bange AA. Accurate casts. J PROETHET DENT 1969;21:545-54.
Reprint requests to: DR. RAY A. WALTERS DENTAL SCHOOL UNMWSI’IT OF MARYLAND BALTIMORE, MD 21201
NOVEMBER
1900
VOLUME
64
NUMBER
5