A method for marking the functional depth of the floor of the mouth

David M. Casey, D.D.S.,* and Frank R. Lauciello, D. D. S. * * Veterans Administration Medical Center, Buffalo, N. Y.

T he depth of the floor of the mouth with the tongue raised determines the location of the inferior

border of the major connector of a mandibular removable partial denture. This depth determines whether a lingual bar or lingual plate major connec-

tor will be used. Because the impressions invariably displace the tissues the cast cannot be used to determine the height of the floor of the mouth in the elevated position.

Several methods have been described for deter- mining the functional height of the floor of the mouth.’ The first involves measuring with a period-

ontal probe the distance from the lingual gingival margin of the lower incisors to the height of the floor of the mouth with the tongue elevated. This

measurement is then recorded on the cast. Another method involves the use of a custom tray that is border-molded in the sublingual crescent region.

The purpose of this article is to describe an easy,

efficient method of marking the functional height of the floor of the mouth and transferring this measure- ment to the diagnostic or master cast.

FABRICATION OF THE MARKING INSTRUMENT

The fabrication of an instrument for palpating and marking the pterygomaxillary notch has been reported (Figs. 1 and 2).’ The instrument consists of a dime soldered to the handle of a mouth mirror. The serrated edges of the dime make an excellent

vehicle for transferring an indelible pencil mark to the oral mucosa. This same instrument can be used to mark the functional height of the floor of the mouth in the sublingual crescent region. The mark-

*Senior resident in Prosthodontics; Clinical Instructor, State University of New York at Buffalo, School of Dentistry.

**Chief of Prosthodontics; Assistant Professor, State University of New York at Buffalo, School of Dentistry.

Fig. 1. The marking instrument is used to palpate for the pterygomaxillary notch.

Fig. 2. The location of the notch is marked with the marking instrument.

ing is transferred to the hydrocolloid impression and then to the cast.

1. Remove the head from a dental mouth mirror, retaining the handle and stem (Fig. 3).

2. Buff the tarnish from a dime with steel wool.

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MARKING FUNCTIONAL DEPTH OF MOUTH

Fig. 3. A mouth mirror is removed from the stem and handle.

Fig. 4. A dime is soldered to the mirror stem with silver solder.

Fig. 5. The back of the marking instrument shows the solder joint.

Fig. 6. The dime is carefully bent to form an approximately W-degree angle to the stem.

Place flux on the dime and solder it to the mirror stem with silver solder (Figs. 4 and 5).

3. Bend the dime to nearly a go-degree angle with the stem (Figs. 6 and 7).

USE OF THE MARKING INSTRUMENT

1. Rub the point of an indelible pencil over the serrated edge of the dime (Fig. 8).

2. Mark the height of the floor of the mouth with the tongue in an elevated position by rotating the serrated edge of the dime over the mucosa (Figs. 9 and 10).

3. Make a reversible or irreversible hydrocolloid impression. The indelible marking will be trans- ferred to the impression (Fig. 11).

Fig. 7. The completed marking instrument.

4. Pour the cast in the impression. The indelible marking is automatically transferred to the artificial stone cast, indicating the functional height of the floor of the mouth (Fig. 12).

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CASEY AND LAUCIELLO

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Fig. 8. An indelible pencil is rubbed over the serrated edge of the dime.

Fig. 9. The functional height of the floor of the mouth while the tongue is elevated is with the instrument.

markeg d

Fig. 10 8. The indelible marking identifies the functional height of the floor of the I nouth.

JANUARY 1980 V ‘OLUME 43 NUMBER 1

MARKING FUNCTIONAL DEPTH OF MOUTH

Fig. 11. The mark is transferred to the hydrocolloid impression.

SUMMARY

The fabrication and use of an instrument which can accurately mark oral tissues and allows transfer

of that mark to an artificial stone cast has been discussed. This procedure is especially useful to mark the anterior floor of the mouth in its superior most position. When transferred to the diagnostic cast, the mark is a considerable aid in designing the inferior

border of the major connector for a mandibular removable partial denture framework (Fig. 13).

We would like to thank Miss Carol J. Payne, Medical Photogra- pher, and the Medical Media Production Service/Photography

section of the Veterans Administration Medical Center, Buffalo, N. Y.

REFERENCES

1. Henderson, D., and Steffel, V. L.: McCracken’s Removable

Partial Prosthodontics, ed 5. St. Louis, 1977, The C. V. Mosby Co., p 22.

2. Robinson, S. C.: To locate the pterygomaxillary notch. J PROSTHET DENT 3:671, 1953.

Reprint requests to:

DR. DAVID M. CASEY

DENTAL SERVICE

VETERANS ADMINISTRATION MEDICAL CENTER

3495 BAILEY AVE.

BUFFALO, N. Y. 14215

- - _ - - . . _ _ .

Fig. 12. The mark is transferred to the diagnostic cast.

Fig. 13. The partial denture framework is designed on the cast; the mark is used to locate the ir.ferior border of the major connector.

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