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Principles a~& tehnique in subli al flangeextenhn of cwmpkte mandibular dentures

Roberto von Krammer K., Cirujano-DentistaSantiago. Chile

M andibular complete dentures frequently lackretention and stability and offer less denture-support-ing area than maxillary dentures. A sublingual flangeextension improves the retention and stability of com-plete lower dentures. It increases he tissue surface ofthe denture, augmenting simple adhesion and, there-fore, retention.2 Stabifity is also enhanced by activeincorporation of tongue activity into the task of main-taining the lower denture in place.

ANATOMIC STRUCTURES INVOLVED

The sublingual flange is placed in the sublingualregion, which is bound posteriorly by the glossopala-tine muscle palatoglossal old) and the lingual slip ofthe superior constrictor muscle of the pharynx. Itsupper limit is the inferior surface of the tongue, and itslower limit the floor of the mouth. Here, its posteriorthird is prescribed by the mylohyoid muscle, which inthis region is quite superficial and often inserts in asharp and prominent bony ridge. In the first molarregion the muscle angles downward and inwardtoward the middle third of the sublingual region, wherethe mylohyoid muscle exerts its influence through thesublingual gland, which lies on top of it. This regionallows for a certain degree of downward displacement.In the anterior third, the inferior limit of the lingualflange is determined by the genioglossus muscle.

PRINCIPLES IN SUBLINGUAL FLANGEEXTENSION

Regardless f the technique used or the constructionof a complete ower denture, a normal tongue position

is important for success Fig. l). Singers and publicspeakers appear to acquire a good tongue positionbecause t favors better resonance nd places he tongueat the best starting point for reaching the differentarticulating zones. If the patient has acquired aretracted tongue position, this bad habit must becorrected before the denture is made.

Abnormal swallowing habits may also underminethe success f a complete lower denture and must becorrected before prosthodontic treatment begins.4-8

Fig. 1. Tongue in normal position in edentulousmouth.

Fig. 2. Acrylic resin custom tray with occlusion rim.

Fig. 3. Border molding with modeling compound.

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Fig. 5. Stone cast. Sublingual flange extension hasbeen outlined by broken line.

Fig. 6. Finished denture.

The function of the anatomic structures that sur-round the sublingual region makes ts size and shapevary. Two dynamic elements control the size and shapeof the sublingual region: the tongue and the floor of themouth. Our goal must be to obtain the maximumpossible xtension of the sublingual flange that will notinterfere with functions of mastication, deglutition, and

Fig. 8. Denture in mouth and tongue in correctposition.

phonation. This extension is accomplished by havingthe patient swallow during the impression-makingprocedures with the tongue in its normal position.

TECHNIQUE

Sublingual flange extensions can be incorporatedinto the impression technique,-I1 developed once thedenture has been waxed,2-4 or formed on the finisheddenture with autopolymerizing acrylic resin.15 Figs. 2to 8 demonstrate the sublingual flange extensiontechnique.

A diagnostic cast is needed o design the tentativefoundation area and to form the custom tray that willconform to this outline. The diagnostic cast can beobtained from an overextended preliminary impression(made from such materials as rreversible hydrocolloidor modeling compound), an adequately rebased exist-ing denture (Fig. 9), or an interim denture that hasbeen ncrementally rebased. The denture foundation isdetermined by the following procedure. The labialflange from one buccal frenum to the other is deter-mined by observing the bottom of the vestibule with the

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SUBLINGUAL FLANGE EXTENSION

Fig. 11. Lower partial denture with distal extensionon left side. Only three natural teeth are left inmandible: Two canines and second right molar. Sub-lingual flange extension provided enough retention sothat clasps were unnecessary on anterior abutments.

Fig. 9. Left, Patients old denture was built up withself-curing acrylic resin and tissue conditioner. Proce-dure was carried out incrementally in successive sit-tings until comfortable denture was produced. Thendiagnostic cast was obtained from it. Right, Newdenture. Note similarity in outline with rebaseddenture.

Fig. 10. In this lower denture, effect of left sidedominance of tongue is prominent.

mouth slightly open. The buccal flange from the buccalfrenum to the retromolar pad reaches p to the externaloblique line, the posterior border covers he retromolarpad completely, and the distolingual border shouldextend downward and backward from the retromolarpad at an angle of approximately 45 degrees.3 Thelingual border follows the mylohyoid ridge up to thefirst molar region. The lingual flange between the firstmolars is also determined by observing the level of thefloor of the mouth with the tongue slightly elevated. Anocclusion rim that simulates he correct occlusal plane

Fig. 12. Sublingual flange extension helps keep inplace this claspless bilateral distal-extension lowerpartial denture.

and the proper arch arrangement is used to helpmaintain a normal tongue position (Fig. 2). Theimpression material of choice is used, and buccal andlabial border molding are accomplished bv the familiarwhistle-grin movements.

The material of choice for the sublingual flangeextension is modeling compound. As this step of theprocedure is carried out, the dentist will note that, inlateral pressure magnitudes, here is dominance of oneside of the tongue, usually the left side (Fig. IO). Of

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VON KRAMMER K.

course, a sublingual flange can also be used to help

keep in place distal-extension lower partial dentures

(Figs. 11 and 12).

REFERENCES

1. W oelfel, J. B., Winter, C. M., and Igarashi, T.: Five-yearcepha lometric study of mandibular ridge resorption with differ-

ent posterior occlu sal forms. Part I: Denture construction andinitial comparison. J PROSTHET DENT 36:602, 1976.

2. Saizar, P.: Protesis a Placa, ed 4. Buenos Aires, 1950,Progrental, p 73.

3. Wright, C.: Evaluation of the factors necessary to developstability in mandibular dentures. J PROSTH ET DENT l&414,1966.

4. Ramfjord, S. P., and Ash, M. M.: Occlus ion, ed 2. Philadel-phia, 1971, W . B. Saunders Co. p 90.

5. Mohl, N. D., and Drinnan, A. J.: Anatomy and physiology ofthe edentulous mouth. In Winkler, S., editor: Symposium oncomp lete dentures. Dent Clin North Am 21:199, 1977.

6. Garliner, D.: Myofunctional Therapy in Dental Practice.Brooklyn, 1971, Bartel Dental Book Co., pp 4-5.

7. Massen gill, R., Robinson, M., and Quinn, G.: Cinefluoro-graphic analysis of tongue-thrusting. Am J Orthod 61:402,1972.

8. Masseng ill, R., Quinn, G., Hall, A. S., and Boyd, D.:

9.

10 .

11 .

12 .

13 .

14 .

15 .

16 .

Tongue-thrusting patterns and the lower incisors . Am J

Orthod 66:287, 1974.Hromatka, A.: Die Methode des Schluckabdruckes zur funk-

tionellen Unterkieferabformung. Schweiz Mschr Zahnheilk65:160, 1955.

Fish, W.: Principles of Full Denture Prosthe sis, ed 6. London,

1964, Staples Press.Tryde, G., Olsson, K., Jense n, S. Aa., Cantor, R., Tarsetano,

J. J., and Brill, N.: Dynamic impression methods. J PROSTH ETDENT 15:1023, 1965.

Barone, J. V.: Physio logic comp lete denture impress ions.

J PROST HET DENT 13:800, 1963.

Cavadini, P. E.: Increased mandibular denture retention by theuse of the flange techniqu e. Dent Digest 72:259, 1966.

Kabc enell, J. L.: More retentive comp lete dentures. J Am Dent

Assoc 8&l 16, 1970.Saxon, H.: Sublingu al extension: Techn ique for loose lower

dentures. Dent Digest 69:10, 1963.Proffit, W. R.: Lingual pressure patterns in the transition from

tongue thrust to adult swallowing, Arch Oral Biol 17:555,1972.

Re,brmt requests to:Dr. ROBER TO VON KRAMMER K.

CASILLA 3501, CORREO CENTRAL

SANTIAGO, CHILE

IADR PROSTHODONTIC ABSTRACT

The influence of overdenture abutment tooth contour upon the periodontium

G. N. Graser and J. CatonEastman Dental Center, Rochester, N.Y.

The purpose of this investigation was to determinethe effect of the height and contour of overdentureabutments upon plaque retention and periodontal

health. Four subje cts were selected with mandibularcusp ids having approximately the same amount of

bone and connective tissue support. One of the twoabutments was reduced to a dome shape allowing no

natural root contour. The contralateral abutment wasreduced to allow 2 mm of the natural peripheral rootcontour to remain coronal to the free gingival margin.

Clinica l parameters were measured at denture inser-tion and thereafter at l-month, 6-month, and l-yearintervals. Param eters included : plaque index (PI),

Reprinted from the Journal of Dental Research [60 (Special issue A),1981 (Abst No. 1365)] with permission of the author and the

editor.

gingival index (GI), pocket depth, gingival marginlocation, loss of attachment, and gingival width.Standardized radiographs were made at insertion and

at 1 year.

Analysis of the results for all subje cts indicated thatno significan t differences in the clinic al parameterswere present when comparing dome-shaped with

natural contour abutments. Two subje cts had high

plaque values (PI = 1.75) and two low (PI = 0).Increase in pocket depth (X = 1 mm) and attachment

loss (X = 1.75 mm) occurred on the dome-shapedabutment in a patient with high plaque levels. Anal-

ysis of radiographs using the Bjom method revealedno significan t change s after 1 year in proximal boneheight for any of the abutments (a = 0.25 Bjorn. units

(BU) dome, and ;i = 0 BU natural). Those abut-ments kept plaque free were assoc iated with a stableand healthy pe riodontium, irrespective of their heightand contour.

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