An impression tray hanger for disinfection

An impression

tray

hanger

for disinfection

John R. Agar, D.D.S., M.A.,* Douglas B. Law, Henry C. Seymour, D.M.D.*** Walter Reed Army Medical Center, Washington, D.C.

D.D.S.,**

and

This article describes in detail a method for making a holder for impression The procedure uses a pattern that can easily he made in the office. A mold from the pattern and parts are processed in acrylic resin. Many parts can from the same mold and several holders can be made before it is necessary remake the mold. (J PROSTHET DENT 1990;63:597-9.)

trays. is made be made to

N

ew varieties of life-threatening disease microorganisms have emphasized the importance of procedures that prevent the cross contamination of patients or staff members.’ Dental professionals must establish and follow effective infection control procedures to prevent such contamination. This article contains instructions for making a simple device to hold impression trays by the handle for disinfection and transportation (Figs. 1 and 2). The advantages of suspending the impression tray by its handle when excess material cannot be trimmed have been discussed by Rudd et aL2 The tray hanger is designed to fit inside a readily available plastic receptacle with a screw lid, such as an empty irreversible hydrocolloid powder container. The tray holder can be used to immerse impressions in disinfecting solutions in the plastic receptacle (Fig. 3). The impression could also be sprayed with a surface disinfectant while on the stand and then placed inside the container so that the system acts as a humidor during the disinfection process (Fig. 3).

PROCEDURE A tray hanger model (pattern) is made in two separate parts and a dental stone mold is made of each part. The two parts of the tray hanger are processed separately in acrylic resin, then bonded together. After the stone molds are made, they can be used to produce any number of acrylic resin impression tray hangers. The pattern for the upright portion of the tray hanger is formed with plastic tubing with 5116 inch and 3116 inch outside diameters reinforced with coat-hanger wire. The

Fig. 1. Impression tray hanger.

**Colonel, U.S. Army, DC; Assistant Chief, Fixed Prosthodontics. ***Major, U.S. Army, DC; Senior resident.

dimensionsof the hangerare shownin Figs. 4 and 5. Coathangerwire l/8 inch in diameter fits snugly insidethe 3116 inch tubing, which hasan inside diameter of l/8 inch, and the 3116inch tubing fits snugly inside of 3116inch tubing, which has an inside diameter of 3116inch. Short piecesof 3116inch tubing within the 5116inch tubing hold the coat hangerwire snugwithin the larger tubing to give it needed support. The coat-hanger wires are slightly overextended

10/l/17395

from the plastic

The opinions expressed herein are those of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. *Colonel, U.S. Army, DC;Director,ProsthodonticResidency Program.

THE

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tubing.

597

AGAR,

LAW,

AND

SEYMOUR

5 la * Fig.

Fig.

2. Hanger with trays.

PATTERN

4. Upright portion of tray holder hanger.

FOR UPRIGHT

1. Cut one piece each of 5116and 3116inch plastic tubing 6 incheslong. 2. Cut a straight piece of coat hanger wire 6% incheslong. 3. Place the coat hanger wire inside of the 3116inch tubing; then place the assemblyinsidethe 5116inch tubing and set it aside.It may be necessaryto lubricate the wire and tubing for easierassembly.Several short piecesof of the 3116inch tubing may be usedinstead of onewhole g-inch piece. 4. Cut two l/2 inch long piecesof 5116inch tubing, two piecesof 3116inch tubing 1 inch long, and two piecesof coat hanger wire 1% inch long. 5. Bend the wire in an arc asshownin Figs. 1 and 4 to form the crossarms. 6. Assemblethe tubing and wire (Fig. 4). 7. Assemble the three parts (Fig. 4) on a flat surface according to the measurementsin Fig. 4 and fix the curved piecesto the long straight piece with adhesive (Household Goop, Eclectic Products Inc., Carson, Calif.).

PATTERN

3. Hanger with trays in container for humidor after surface spraying or for immersiondisinfection. Fig.

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FOR BASE

1. Make six 1‘/z inch lengthsof 5/16 inch plastic tubing and reinforce each with 3116inch tubing and coat-hanger wire. 2. Make a mix of autocuring acrylic resin and form it into a disk approximately 1% inches in diameter and 5/16 inch thick. 3. Place one end of each of the six lengths of reinforced MAY

1930

VOLUME

63

NUMBER

6

5. Baseportion of tray hangerwith dimensions.Side view crosssectionwith reduced portion in underbase. Fig.

plastic tubing approximately 3/8 inch into the resin disk arranged like the spokesof a wheel equidistant from each other (Fig. 5). Allow the acrylic resin to set, reinforce the attachment of the tubing to the acrylic resin with adhesive,and let the adhesive set. Grind the center of the bottom of the baseso that it is slightly raised, compared with the outer spokes, to increaseits stability when the holder is in use(Fig. 5). Cut or drill a 5/16 inch hole through the center of the hub portion of the base (Fig. 5). Note: This step could be done after the basepart is processedin acrylic resin.

DENTAL

STONE

MOLD

1. Make a separateform of boxing wax large enoughto accommodate each pattern with a land shoulder of approximately 1 inch from each portion of each pattern. 2. Fill eachform with a mix of dental stoneand smooththe top surface. 3. Place each pattern in its respective box and sink the pattern in the stone to one half the depth of the pattern. 4. When the stone has set, cut orientation indexes in the land of each of the stone investments. 5. Box the stone half flasks, coat the surfaceswith a separating medium, and fill each of the boxingswith dental stone.

RESIN

PARTS

patterns, and clean the molds. 2. Apply separating medium to the molds and pack the molds with autopolymerizing acrylic resin.

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ASSEMBLY 1. Fit the upright into the hole in the base. It should be

snug. 2. If the bottom of the basewas not ground in step 5 of

“Pattern For Base,” it must be done now (Fig. 5). 3. Place the two parts together, with the long part inserted in the hole flush with the bottom side of the base. 4. Apply wet acrylic resin to the junction of the baseand the upright with a camel hair brush and allow it to set. 5. Touch up the polish, and the tray hanger is complete. When the molds for the hanger parts are completed, severalparts may be madebefore it is necessaryto remake the mold; however, the pattern shouldbe savedto useagain if necessary. Weexpress ourappreciationto Ms.VenetiaV&a of theArmed Forces Institute

of Pathology for the illustrations

in this article.

REFERENCES 1. Council on Dental Materials, Instruments and Equipment, Council on Dental Practice, Council on Dental Therapeutics. Infection control recommendations for the dental office and the dental laboratory. J Am Dent Aeeoc 1988;116:241-8. 2. Rudd KD, Morrow RM, Benge AA. Accurate casts. J PROSTHET DENT 1969;21:545-54.

1. When the stone sets, separate the flasks, remove the

THE

3. Compressthe moldsuntil the resin sets,then separate. 4. Recover the parts, remove the flash, round the ends, finish, and polish the acrylic resin.

DENTISTRY

Reprint requests to: DR. JOHN R. AGAR 1601 OAKLAWN CT. SILVER SPRING, MD 20903

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