CHA~ACTE~~ST~CS OFSOLDERINDEXMATERIALS

standard deviation with the material. The relatively large standard deviations for the two resin materials is not unexpected, because it is difficult to produce a repeatable consistency of material using the powder-liquid brush technique. However, even with these large standard deviations, there was a significant difference between the materials, with ZAPIT material showing the highest mean tensile strength and Relate material showing the lowest. Since all tensile failures were adhesive, the slight variations in thickness of the indexing materials as a result of the preindexed gap distance variations were not a factor in the results.

REFERENCES 1. Fusayama T, Wakumoto S, Hosoda H. Accuracy of fixed partial dentures made by various soldering techniques and one-piece casting. J P~o~~~~~D~~~1964;14:334-42. 2. Shillingburg HT, Hobo S, Whitsett LD. Fundamentals of fixed prosthodontics. 2nd ed. Chicago: Quintessence, 1981:403. 3. Stackhouse JA. Assembly of dental units by soldering. S PXOSTHET DENT 1967;18:131-8. 4. Meyer FS. The elimination of distortion during soldering. J PROSTHET DENT 1959;9:441-7. 5. Patterson JC. A technique for accurate soldering. J PROSTHETDENT 1972;28:552-6. 6. Moon PC, Eshleman JR, Douglas HB, Garrett SG. Comparison of accuracy of soldering indices for fixed prostheses. J PBOSTHETDENT 1978;40:35-8. 7. Harper RJ, Nicholls JI. Distortions in indexing methods and investing media for soldering and remount procedures, J PROSTHETDENT 1979;42:172-9.

c Sased on the results of this investigation, ZAPIT should be considered as the material of choice for indexing castings on a working cast. However, because its safety for use in the oral cavity has not been proven, Duralay material remains the indexing material of choice for use intraorally because of its high tensile strength.

Reprint requests to: DR.DONNAL.DIXON UNIVERSITYOFIOWA COLLEGEOFDENTISTRY DEPARTMENTOFPROSTHODONTICS IOWACITY,IA 52242

omposite resin buttons used to direct vable orthodontic devices harles Timothy

A. Netti, DDS,a Michael K. Jones, DDSC

Ft. Sam Houston,

Tex., Ft. Riley, Kan.,

D. Albright,

DDS,

forces applie

MS,b and

and Nuremburg, Germany

Limited orthodontic treatment prior to preparing and making prosthodontic restorations will often enhance the final outcome. A technique using grooved acid-etch composite resin buttons bonded to teeth will increase the effectiveness removable orthondontic devices. (J PROSTHET DENT 1992;67:729-31.)

he status, condition, and alignment of the dentition and its supporting structures must be in optimum condition before prosthodontic restorations are made. One of the criteria should be that the position and alignment of

The opinions or assertions contained 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. Commercial materials and equipment are identified in this article to specify the procedure. Such identification does not imply official recommendation or endorsement or that the materials and equipment are necessarily the best available for the purpose. aLieutenant Colonel, U.S. Army, DC; Deputy Commander and Chief of Fixed Prosthodontics Department. U.S. Army Area Dental Laboratory, Ft. Sam Houston, Tex. bLieutenant Colonel, U.S. Army, DC; Chief and Mentor, Orthodontics Department, U.S. Army DENTAC, Ft. Riley, Kan. %ieutenant Colonel, U.S. Army, DC; OIC Erlangen Dental Clinic, 87th Med. Detachment, Nuremburg, Germany. %0/1!35861 THE JOURNAL OF PROSTHETIC DENTISTRY

of

the remaining teeth relative to each other and the proposed restoration are evaluated, and corrected if possible. When minor misalignments are present, they can be easily corrected or compensated for during tooth preparation. If, however, the repositioning of certain teeth would enhance the overall final treatment outcome, orthodontic realignment must be considered. Fixed orthodontic devices usually are more desirable than removable devices because of the greater amount of control and treatment flexibility obtained. Occasionally, teeth that are malaligned may be treated with removable orthodontic devices advantageously. Effective use of removable devices is dependent on keeping an adequate force applied to the dentition to move the teeth in the direction desired. With removable devices, the active forces are usually applied by labial or lingual arch wires and finger springs. After the removable device has been in place in the mouth and particularly after some movement has been achieved, keeping the active force di729

NETTI,

Fig:. Fig. Fig. Fig. row).

1. 2. 3. 4.

ALBRIGNT,

AND

JONES

Completed removable orthodontic device ready for placement. Composite resin button on tooth polished and grooved (arrow). Wire positioned in composite resin groove. Button is designed to cause wire to direct more force to distal surface of tooth (or-

slippage and maintain control of the magnitude and direction of the forces being used. PROCEDURE

5, Wire in position to examine for interference of opposing dentition by resin button or wire.

Fig.

rected becomes a problem. This is primarily because of slippage of the wire on the tooth and decreasing adjustment control. This article describes an easy technique to limit this

730

1. Design and make a removable orthodontic device in the usual manner (Fig. 1). Take into consideration the desired direction of tooth movement, how it is to be accomplished, and possible interferences. 2. With the device in place, select the position on the tooth for optimal wire placement and mark its position. 3. Remove the device and build a composite resin button on the tooth at the marked position by using an acid etch procedure. 4. After the composite resin is cured, smooth and polish it so that it is not irritating to the patient and will not accumulate debris and plaque (Fig. 2). Use a size 1/2or 1 round bur, depending on wire diameter, to cut a groove in the button deep enough to hold the wire. When the wire is seated in the groove, it functions as a positive anchor for the wire and directs the active forces (Fig. 3). Position the device with the wire in the resin button groove. Examine it for occlusal interferences, and the

MAY

1992

VOLUME

67

NUMBER

5

desired position of the wire on the tooth (Figs. 4 and 5). When corrections are needed, the button can be modified by removing or adding composite resin.

At subsequent fallow-up appointments, progress can be evaluated and further adjustments made as required. The Aexibility obtained by using a grooved resin button is important. (1) The patients can keep the wire properly oriented after removing and replacing the device because they can feel the wire snap into the groove. (2) The force

ui Majid

or the buccolingual Eissasu,

DDS,

Dental Center, Ministry

appiication point can be moved easily to the mesial or distal direction, or occlusal or gingival direction, as movement occurs. (3) The magnitude of the applied force can be maintained, increased, or decreased by simply altering the size of the button. These features often negate the need to remake the device during treatment, saving time and expense while expediting the desired outcome. Reprint

requests to:

DR. CHARLESA.NETTI U.S. ARMYAREADENTALLABORATORY FT.SAM HOVSTOIV,TX 78234

position

of the posterior

PhDa of Public Health,

Kuwait

Marks transferred from a mandibular’ cast to a mandibular wax occlusion rim can be a decided advantage in helping set posterior teeth in the proper position. (J PROSTHET DENT 1992;67:731-2.)

he arrangement of the posterior teeth plays a significant part in the retention and stability of the denture and the condition of the supporting tissues. The mandibular ridge and its surrounding structures offer reliable landmarks for setting the mandibular posterior teeth. The mandibular denture is more difficult to stabilize and has less support than the maxiliary denture. Mandibular teeth should be set in a manner to reduce lateral forces on the residual ridges. Because of the more critical limitations to the position of the mandibular teeth, it is recommended that the mandibular posterior teeth be set first.l This is best accomplished by placing the central groove of the mandibular posterior teeth over the crest of the mandibular residual ridge.2-4 Many mandibular posterior teeth are set without a guide or with a variety of guides. A useful guide is a line drawn with a pencil on the crest of the ridge on the cast and extended to the anterior and posterior part of the cast. However, when a baseplate and occlusion rim are on the cast, this line is covered. This article presents a simple aid for establishing the buccolingual position of the mandibular posterior teeth on the residual ridges by using a line marked on a wax occlusion rim.

aProsthodontist,

Department

of Removable

10/l/35096

THE JOURNALOF

PROSTHETIC DENTISTRY

Prosthodontics.

PROCEDURE This procedure may be adapted to most techniques for making maxillary and mandibular complete dentures. The marks may be placed on the wax occlusion rim by grooving the wax. When wax is not used for recording the jaw relation, record wax will be used for setting the teeth and a simulated wax occlusion rim can be made at that time. 1. Place pencil marks on the mandibular cast bilaterally distal to the mandibular canine and at the apex of the retromolar pad (Fig. 1). 2. If the mandibular cast is already mounted in an articulator, remove it. Mount the cast on the cast bolder of a surveyor with the occlusal plane in a borizontal position. 3. Place the tip of the analyzing rod on a pencil mark (Fig. 1). When the surveyor has a mobile horizontal arm, lock it in a forward position. 4. To transfer the pencil marks from the cast to the mandibular wax occlusion rim, hold the cast and holder firmly in the fixed position. 5. Raise the surveying arm of the surveyor and place the mandibular wax occlusion rim on the cast. 6. Lower the surveying arm until the tip of the analyzing rod contacts the wax, and press hard enough to make an indentation (Fig. 2). 7. Repeat steps 3 through 6 until all four pencil marks are transferred to the wax rim. 8. Scratch a line on each side by using a straightedge and

731