Stabilizing periodontally weakened teeth by using guide plane removable partial dentures: A preliminary report

STABILIZING PERIODONTALLY WEAKENED TEETH BY USING GUIDE PLANE REMOVABLE PARTIAL DENTURES: A PRELIMINARY REPORT

TIMOTHY

D. RUDD, COLONEL, USAF (DC) *, AND J. O’LEARY, COLONEL, USAF (DC) * *

Lackland

Air Force Base, Tex., and Brooks

KENNETH

Air Force Base, Tex.

HE PERIODONTIUM holds the tooth in the alveolus and transmits to the bone any force which acts upon the crown of the tooth. If the periodontium is in a sound, healthy condition, it can transmit normal intermittent forces without exceeding its physiological limits and destroying itself. It appears that it is essential for the periodontium to perform some function in order to maintain its state of hea1th.l A biostatic equilibrium exists between the forces of action and reaction in a healthy functioning mouth. Any change in these forces disturbs the equilibrium and produces qualitative as well as quantitative changes in the periodontium manifested by the loosening of the tooth. Physiologically, the periodontium permits the tooth to move in three different directions : ( 1) vertical, (2) mesiodistal, and (3) buccolingual. The tooth is least able to withstand excessive lateral forces, which are associated with an increase of movement in the buccolingual direction. Therefore, measurement of the amount of this movement will permit early identification of periodontal changes, it can be made with the least interference from other teeth. It has been shown that increased tooth mobility or loosening of teeth is a cardinal symptom of periodontal disease.’ However, the severity of the disease cannot be established without an objective assessment of the magnitude of tooth mobility. For measurements to be comparable and meaningful, they must be reproducible by one dentist in the same mouth and by two dentists in the same or other mouths. This comparison is not reliable when personal or subjective judgments are used as in Miller’s3 classification (method), in which he recognizes three levels of increased tooth mobility.

T

METHODS OF MEASUREMEKT

OF TOOTH MOBILITY

In Miller’s system, a tooth is activated by grasping it between the fingers or between two instrument handles and moving it from side to side. First degree Read before the Academy of Denture Prosthetics, Miami Beach, Fla. *Chairman, Department of Prosthodontics, Wilford Hall USAF Hospital, Aerospace bledi.cnl Division (AFSC). **Chief, Clinical Dentistry Branch, School of Aerospace Medicine, Aerospace Medical Division (AFSC). 721

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mobility is the first distinguishable sign of movement greater than normal. Second degree mobility allows the crown to move as much as 1 mm. in a buccolingual direction. Third degree mobility allows the tooth to move more than 1 mm. in a buccolingual direction or to be depressed in its socket. Being subject to individual interpretation, such classifications have a low rate of reproducibility. Several methods have been devised for measuring tooth mobility more accurately. Extra-oral methods were developed by Elbrecht,4 Werner,5 and Cross6 These methods must be considered still in the developmental stage, but with continued application, they may be improved considerably. Beyeler,7 Drefus,s and Manley, Yurkstas, and Reswick,g worked with the Virtometer, and LundquistlO used an electromagnetic mobility recorder. The use of instruments with different operating principles has resulted in the development of new techniques. Although showing much promise, they have not yet progressed beyond the experimental stage. Pictonrl and Parfittl” have reported on the use of electronic systems for the measurement of tooth mobility. These systems are undoubtedly extremely accurate but appear to be too time consuming for routine clinical use. Two of the most reliable methods were derived from Zwirner13-l5 and Miihlemann.ls The authors did not use Zwirner’s method because the apparatus is relatively complicated. Miihlemann 2 has published many reports concerning tooth mobility and its variations within the past decade. The authors are indebted to him for the methodology of measuring tooth mobility and these studies were begun with the Macroperiodontometer which he devised. The instrument was satisfactory for measuring from the left first bicuspid to the right first bicuspid in each arch but the remaining teeth could not be measured easily or accurately. Miihlemann2 reported mobility values for molars obtained with the Microperiodontometer, but observed that the results were less reproducible than with the Macroperiodontometer.

Fig.

L-The

instrument

used

to measure carrier

tooth mobility. (1) and dial indicator.

The

clutch

and

bite

block.

(2)

The

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The instrument (Fig. 1 j devised by the authors consists of two parts : (1) an intra-oral clutch with bite block and (2) a carrying vehicle supporting a dial indicator. Force is applied to the tooth (Fig. 2) by means of a Forcemeter modified by lengthening the force arm and recalibrating the dial. A force of 500 Gm. is applied to the tooth because, from the work of JLIiihlemann, this appears to be the optimum amount to apply. The instrument I7 has proved to be versatile and extremely accurate and the readings obtained are reproducible. A dentist thoroughly familiar with the system can measure movement of the 25 teeth in the mouth within 45 minutes. The instrument is more than a research tool. It is of value in both clinical diagnosis and evaluation of therapy instituted for a patient, whether this is a simple restoration or a surgical, periodontic, orthodontic, or prosthodontic procedure. An investigation of normal tooth mobility has been completed and can be used as a comparison for values obtained.18 TREATMENT

OF

MOBILE

TEETH

WITH

GUIDE

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The remaining natural teeth of the patients (subjects) in this study had at best only a fair long-term prognosis. Moderate to severe bone loss and pathologic mobility patterns around all teeth complicated the restorative problem. To provide support for the necessary prosthesis, it is essential that these teeth be maintained without further destruction. A prosthodontic restoration can either aid in stabilizing the entire arch or, if poorly conceived and executed, soon lead to the loss of the remaining natural teeth. Mobile teeth may be stabilized by fixed or removable splinting. This investlgation was begun to determine whether weakened teeth could be stabilized with

Fig.

Z.-The

modified

Forcemeter

used

to apply

a measured

amount

of

force

to the

tooth.

J. Pros. Den. July-Au&, 1966

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accurately fitted splint-type guide plane removable partial dentures. Partial dentures have been completed for 12 subjects and, in every instance, tooth mobility has remained the same or decreased. The longest test period, however, has been less than two years, and some of the partial dentures have been worn for only a few months. The project will be continued indefinitely and many more patients will be included as subjects. Fig. 3a shows the cast of a typical arch soon after completion of periodontal therapy. The height of contour is very close to the occlusal surface of the teeth and the length of the clinical crown has been increased in proportion to the root. The lingual surfaces of the remaining posterior teeth were ground carefully until they were parallel (Fig. 3b) and then polished. These surfaces serve as guide planes to support the teeth as the partial denture is being seated, and to brace against lateral movements after the partial denture is in place. If the teeth could not be ground adequately without penetrating the enamel, gold castings were placed on the teeth. Quite frequently it is necessary also to grind the buccal and labial surfaces in order to obtain more favorable clasping positions. . Photographs (Fig. 4) show the condition of a subject’s mouth before treatment. Tooth mobility was measured and recorded prior to periodontal therapy. The right and left sides of the same mouth one month after comprehensive perio-

tours guide

Fig. 3.-(A) A cast of a dental arch after periodontal near the occlusal surfaces of the teeth. (B) A cast planes developed by recontouring the teeth.

Fig.

4.-(A)

The

right

side of a subject’s

mouth

before

therapy showing of the same dental

treatment.

(B)

the height of conarch showing the

The

left

side.

;;lbble;

‘4”

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dontal therapy are shown (Fig. 5). Mobility of the lower anterior teeth was so severe that they were stabilized with a temporary wire and acrylic resin splint during the periodontal treatment. The guide plane removable partial dentures (Fig. 6) are seated in the subject’s mouth about eight weeks after completion of periodontal therapy. IThen the teeth are mobile, it is desirable to clasp all remaining posterior teeth and the cuspids. However, it is not mandatory that all clasp arms engage undercuts. In similar situations, when a clasp has not been placed on the first pre-. molar, the tooth did not tighten until a clasp had been added. Apparently, it is necessary to restrain the tooth from moving buccally under stress. An adequate rest on the unclasped tooth is not sufficient to stabilize it. Full palatal coverage is used for added support for the denture (Fig. 7). If the teeth are spaced, the solid lingual metal plate may be broken to avoid an unsightly appearance. The metal must be adapted perfectly to the contours of the lingual surfaces of the teeth. It must be thin and have a sharp margin that fits snugly against the teeth in order to deflect food away from the teeth and onto the metal. ri photograph (Fig. S) of the mandibular arch of another subject shows small fingers over the incisal edges of the lower teeth to stabilize them. If a chrome alloy is used, the fingers can be made quite thin and inconspicuous without sacrificing effectiveness. When these fingers are not necessary for stabilization of the teeth, a lingual plate may be used. The margin of the metal must follow closely the contouri of the teeth. The same rules for tooth and metal contouring apply in both the

Fig.

5.-(ii)

The

Fig.

6.-(A)

The

right

right

side

side

of

the

same therapy.

mouth one month (B) The left side.

after

comprehensive

of the mouth of the same patient with a guide in place. (B) The left side of the mouth.

plane

periodontal

partial

denture

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mandibular and the maxillary arches. All major connectors must be nonflexible and above all, the partial denture must be passive when it is in place in the mouth. After the castings are completed, it is essential to fit the dentures to the mouth. This is accomplished by flowing a very thin layer of white disclosing wax inside the clasps and other parts of the partial denture which come into contact with the teeth. The casting is placed in the mouth and firmly seated. On removing the casting from the mouth, it is possible to determine how far it is from being completely seated. If the point of a sharp instrument is dragged across the wax remaining under the rest, the thickness of the wax will show how much the denture lacks of being seated. At the same time, metal shows through the wax wherever the

Fig. 7.-A maxillary removable support and the interrupted lingual anterior teeth are spaced.

Fig

8.-Remoyable

partial

dqqtgrgs

partial plate

denture to avoid

in place showing for stabillzat!Qpl

showing the an unsightly

small

full palatal exposure

projection

oyq

coverage of metal

the

for added when the

anterior

teeth

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clasp, the rest, and the minor or major connector are binding on a tooth, indicating exactly where to grind in order to permit the denture to seat. In this investigation, the 12 subjects treated had a total of 219 natural teeth remaining. Before periodontal therapy, the mean mobility of the 219 teeth was 0.011 Sin. One month after completion of periodontal treatment, the mean mobility of the 219 teeth was 0.0104 mm. The guide plane partial dentures were inserted from 1 to 3 months after completion of active periodontal treatment. One month after insertion of the removable prosthesis, the mean mobility was 0.0096 mm. The mobility changes were comparable for the clasped and nonclasped teeth. SUM

MARY

This investigation on the stabilization of periodontally weakened teeth with removable partial denture prosthesis cannot be considered conclusive because of the relatively short time interval. However, data accumulated during a period of two years indicate that carefully planned, designed, fabricated, and fitted removable guide plane partial dentures may be effective in stabilizing mobile teeth. REFERENCES 1. 2. 3. 4.

Miihlemann, H. R., Herzog, H., and Rateitschak, K. H.: Occlusion and Articulation in the Etiologic Complex of Periodontal Disease, Parodontal. Zurich 11:20, 1957. Miihlemann, H. R. : 10 Years of Tooth-Mobility Measurements, J. Periodont. 31:110-122, 1 OflO Miller, S. C.: Textbook of Periodontia, ed. 3, Philadelphia, 1950, Blakiston Division, McGraw-Hill Book Company, p. 125. Elbrecht, A.: Beitrag zur Bestimmung der Lockerungsgrade der Ziihnt, Paradentium

11:138. 1939.

5. Werner,, 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.

V.: Vergleichende Untersuchungen verschiedener Paradentose-Behandlungen nnttels einer neuen metrischen methode, Paradentium 14:43, 1942. Cross, W. G.: A Special Instrument to Measure Tooth Moblhty, Demonstration to the British Society of Periodontology,. Sept. 4, 1951. lieyeler, K., und Drefus, J.: Prinzip Emer electrodynamischen apparatur zur lockerungsgrades der Zihne, Parodentologie 1:113,, 1947. Dreyfus, J.: Le Vibrometre Dynamique, Theorie et Applications d’un Nouvel Instrument Electrique de MOsures Mecaniques, Schweiz. Arch. Angew. Wiss. Tech. 15:338, 1949. Manly, R. S., Yurkstas, A. A., and Reswick, J. B.: An Instrument for Measuring Tooth Mobility, J. Periodont. 22:148-l%, 1951. Lundquist, C. : Objektiva Paradontala Registreingsmetoder, Odont. Revy. 7:9, 1956. Picton, D. C. A.: A Method of Measuring Physiological Tooth Movements in Man, J. 13. Res. 36:814. 1957. Parfitt, G. J.: Measurement of the Physiological Mobility of Individual Teeth in an Axial Direction, J. D. Res. 39:608-618, 1960. Zwirner, E. : VerwendungsmGglichkeiten des Kathodenstrahloszillographen zu Forschungszwecken in der Zahn, Mund und Kiefernheilkunde, Deutsche Zahnirtzl. Ztg. 4:794, 1949. Zwirne;, 3F. igphweis von Zahnbewegungen in Tierverscuh, Deutsche Zahn%rtztl. Ztg. :. . Zwirner, El : Untersuchugen iieber die Arbeitsweise des Sogenannten alveolodentalen gelenkes bei der ratte und die bisherigen Ergebnisse, Deutsch. Zahn, Mund-u. Kieferheilk. 15:462, 1952. Miihlemann, H. R.: Tooth Mobility. The Measuring Method, Initial and Secondary Tooth Mobility, J. Periodont. 25:22-29, 1954. O’Leary, T. J., and Rudd, K. D. : An Instrument for Measuring Horizontal Tooth Mobility, Technical Documentary Rpt No. SAM-TDR 63-58, USAF School of Aerospace Medicine, Brooks AFB, Tex. ; Periodontics 1:249-254, 1963. Tooth Mobility in CareRudd, K. D., O’Leary, T. J., and Stumpf, J. J., Jr.: Horizontal fully Screened Subjects, Technical Documentary Rpt. No. SAM-TDR 64-12, USAF School of Aerospace Medicine, Brooks AFB, Tex.; Periodontics 2:65-68, 1964.

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