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Sublingual extension
Sublingual extension
Roberto von Krammer K., Cirujano-Dentista,! Santiago, Chile
A sublingual flange improves the retention and stability of complete lower dentures. Structures and principles involved in the development of the flange are discussed. The technique is illustrated.
The lower complete denture is difficult to retain in place over the lower ridge, and its stability is easily upset. A sublingual flange or extension in creases the tissue surface covered by the den ture, places the lingual border seal in a more fa vorable zone, and incorporates the tongue into the task of maintaining the lower denture in place. Hromatka,1 Tryde,2 and Fish3 incorporate the sublingual flange into their impression tech nique. Kabcenell4 also obtains it through his im pression technique or develops it once the den ture has been waxed up. At this stage, Cavadini5 develops the sublingual flange using wax, but Barone6 uses zinc oxide-eugenol (ZOE) paste. Saxon7 makes the sublingual extension with cold-curing acrylic resin on the finished denture. I believe that the dentist should incorporate the sublingual extension into his usual impres sion technique. In order to do this, he must un derstand the structures and principles involved.
Tongue
If we want it to help maintain the lower denture in its place, the tongue must be in its normal posiJADA, Vol. 88, March 1974 ■ 585
Fig 1 ■ Normal ton gue position in edentulous m outh. Fig 2 ■ Individual tray. Border m olding w ith m odeling com pound.
tion8 (Fig 1). If it is not, the tongue m ust be trained to reacquire it before the denture is made. I f a patient persists in keeping his tongue in a retracted position, the sublingual extension will be useless.
S u blingua l region T h e upper limit o f the sublingual region is the inferior surface of the tongue. Posteriorly, the region is bound by the glossopalatine muscle and the lingual slip of the superior constrictor of the pharynx. T he lower limit is prescribed in the posterior third by the m ylohyoid m uscle, which in this region is quite superficial. In the first mo lar region the m uscle starts descending, marking the beginning of the middle third; here the mylo hyoid m uscle exerts its influence through the sub lingual gland, which lies on top of it. This region adm its a certain degree of displacem ent. In the an terior third, the inferior limit is determ ined by th e genioglossus muscle. T he edentulous ridges are the lateral and anterior limits of the region. ■ Behavior o f the sublingual region during fu n c tion: T he functions of the elem ents that sur round the sublingual region make the size and shape of it vary. This, in turn, governs the exten sion of the sublingual flange. Tw o dynam ic ele m ents can be said to control the size and shape of the sublingual region: the tongue and the floor of the m outh. T he starting point for all their m ovem ents is the normal position of the tongue. T his position represents the maximum possible extension for the sublingual flange. From it, only th e necessary leew ay for the unim peded, mini m um , indispensable functions of the tongue and floor of the m outh (m astication, deglutition, and phonation) need be deducted. This is accom586 ■ JADA, Vol. 88, M arch 1974
Fig 3 ■ Im pression (ZOE paste).
plished by having the patient swallow during the im pression making, with the tongue in its normal position.
T echnical principles T he basic problem for the beginner is to know how far the sublingual flange can be extended. This problem can be alleviated if the im pression m aterial is introduced in a semifluid state into the m outh. H ow ever, once bounded and molded by the chosen function (deglutition), the im pression m aterial m ust m aintain its acquired form. Im pression plaster, reversible and irreversible hy drocolloid, Z O E paste, and silicone and mercaptan rubber are among the appropriate im pression m aterials. They can be used to develop the com plete im pression or to rebase a basic im pression. O nce the clinician has gained m ore experience, he may use heavy im pression m aterials such as modeling com pound to form the im pression, being careful to avoid overextension.
Fig 7 ■ Tissue-side view of same denture. Fig 4 ■ Occlusal view of im pression.
Fig 8 ■ Denture in mouth. Note its relationship to tongue.
r *
a sublingual flange has been tried out with coldcuring acrylic resin and tissue conditioners, o r an unsuccessful previous im pression with a sub lingual extension. N ext, modeling com pound is used for border molding, both in the usual per ipheric areas and the sublingual region (Fig 2). Finally, the im pression is m ade with synthetic rubber or Z O E paste (Fig 3-8).
Dr. von Kram m er's address Is Casilla 3501, Correo Central, Santiago, Chile.
Fig 6 ■ Finished denture.
■ Technique: T he technique is described and illustrated as an exam ple o f sublingual exten sion with a light im pression m aterial. An indi vidual tray (acrylic resin or metal) is made over a model obtained from a prelim inary overex tended im pression, an old denture from which
1. Hromatka, A. Die M ethode des S cluckabdruckes zu r fun ktion ellen U nterkieferabform ung. Schweiz M onatsschr Zahnheilkd 65:160 No. 2, 1955. 2. Tryde, G., and others. D ynam ic im pression methods. J Prosthet Dent 15:1023 Nov-Dee 1965. 3. Fish, E. W. P rinciples of full denture prosthesis, ed 6. Lon don, Staples Press, Ltd., 1964. 4. Kabcenell, J. L. More retentive com plete dentures. JADA 80:116 Jan 1970. 5. Cavadini, P. E. Increased m andibular denture retention by the use of the flange technique. Dent Dig 72:259 June 1966. 6. Barone, J. V. P hysiologic com plete denture im pressions. J Prosthet Dent 13:800 Sept-Oct 1963. 7. Saxon, H. Sublingual extension. Technique fo r loose low er dentures. Dent Dig 69:10 Jan 1963. 8. W right, C. Evaluation o f the factors necessary to develop s tab ility in m andibular dentures. J P rosthet Dent 16:414 MayJune 1966. von Krammer: SUBLINGUAL EXTENSION ■ 587
Roberto von Krammer K., Cirujano-Dentista,! Santiago, Chile
A sublingual flange improves the retention and stability of complete lower dentures. Structures and principles involved in the development of the flange are discussed. The technique is illustrated.
The lower complete denture is difficult to retain in place over the lower ridge, and its stability is easily upset. A sublingual flange or extension in creases the tissue surface covered by the den ture, places the lingual border seal in a more fa vorable zone, and incorporates the tongue into the task of maintaining the lower denture in place. Hromatka,1 Tryde,2 and Fish3 incorporate the sublingual flange into their impression tech nique. Kabcenell4 also obtains it through his im pression technique or develops it once the den ture has been waxed up. At this stage, Cavadini5 develops the sublingual flange using wax, but Barone6 uses zinc oxide-eugenol (ZOE) paste. Saxon7 makes the sublingual extension with cold-curing acrylic resin on the finished denture. I believe that the dentist should incorporate the sublingual extension into his usual impres sion technique. In order to do this, he must un derstand the structures and principles involved.
Tongue
If we want it to help maintain the lower denture in its place, the tongue must be in its normal posiJADA, Vol. 88, March 1974 ■ 585
Fig 1 ■ Normal ton gue position in edentulous m outh. Fig 2 ■ Individual tray. Border m olding w ith m odeling com pound.
tion8 (Fig 1). If it is not, the tongue m ust be trained to reacquire it before the denture is made. I f a patient persists in keeping his tongue in a retracted position, the sublingual extension will be useless.
S u blingua l region T h e upper limit o f the sublingual region is the inferior surface of the tongue. Posteriorly, the region is bound by the glossopalatine muscle and the lingual slip of the superior constrictor of the pharynx. T he lower limit is prescribed in the posterior third by the m ylohyoid m uscle, which in this region is quite superficial. In the first mo lar region the m uscle starts descending, marking the beginning of the middle third; here the mylo hyoid m uscle exerts its influence through the sub lingual gland, which lies on top of it. This region adm its a certain degree of displacem ent. In the an terior third, the inferior limit is determ ined by th e genioglossus muscle. T he edentulous ridges are the lateral and anterior limits of the region. ■ Behavior o f the sublingual region during fu n c tion: T he functions of the elem ents that sur round the sublingual region make the size and shape of it vary. This, in turn, governs the exten sion of the sublingual flange. Tw o dynam ic ele m ents can be said to control the size and shape of the sublingual region: the tongue and the floor of the m outh. T he starting point for all their m ovem ents is the normal position of the tongue. T his position represents the maximum possible extension for the sublingual flange. From it, only th e necessary leew ay for the unim peded, mini m um , indispensable functions of the tongue and floor of the m outh (m astication, deglutition, and phonation) need be deducted. This is accom586 ■ JADA, Vol. 88, M arch 1974
Fig 3 ■ Im pression (ZOE paste).
plished by having the patient swallow during the im pression making, with the tongue in its normal position.
T echnical principles T he basic problem for the beginner is to know how far the sublingual flange can be extended. This problem can be alleviated if the im pression m aterial is introduced in a semifluid state into the m outh. H ow ever, once bounded and molded by the chosen function (deglutition), the im pression m aterial m ust m aintain its acquired form. Im pression plaster, reversible and irreversible hy drocolloid, Z O E paste, and silicone and mercaptan rubber are among the appropriate im pression m aterials. They can be used to develop the com plete im pression or to rebase a basic im pression. O nce the clinician has gained m ore experience, he may use heavy im pression m aterials such as modeling com pound to form the im pression, being careful to avoid overextension.
Fig 7 ■ Tissue-side view of same denture. Fig 4 ■ Occlusal view of im pression.
Fig 8 ■ Denture in mouth. Note its relationship to tongue.
r *
a sublingual flange has been tried out with coldcuring acrylic resin and tissue conditioners, o r an unsuccessful previous im pression with a sub lingual extension. N ext, modeling com pound is used for border molding, both in the usual per ipheric areas and the sublingual region (Fig 2). Finally, the im pression is m ade with synthetic rubber or Z O E paste (Fig 3-8).
Dr. von Kram m er's address Is Casilla 3501, Correo Central, Santiago, Chile.
Fig 6 ■ Finished denture.
■ Technique: T he technique is described and illustrated as an exam ple o f sublingual exten sion with a light im pression m aterial. An indi vidual tray (acrylic resin or metal) is made over a model obtained from a prelim inary overex tended im pression, an old denture from which
1. Hromatka, A. Die M ethode des S cluckabdruckes zu r fun ktion ellen U nterkieferabform ung. Schweiz M onatsschr Zahnheilkd 65:160 No. 2, 1955. 2. Tryde, G., and others. D ynam ic im pression methods. J Prosthet Dent 15:1023 Nov-Dee 1965. 3. Fish, E. W. P rinciples of full denture prosthesis, ed 6. Lon don, Staples Press, Ltd., 1964. 4. Kabcenell, J. L. More retentive com plete dentures. JADA 80:116 Jan 1970. 5. Cavadini, P. E. Increased m andibular denture retention by the use of the flange technique. Dent Dig 72:259 June 1966. 6. Barone, J. V. P hysiologic com plete denture im pressions. J Prosthet Dent 13:800 Sept-Oct 1963. 7. Saxon, H. Sublingual extension. Technique fo r loose low er dentures. Dent Dig 69:10 Jan 1963. 8. W right, C. Evaluation o f the factors necessary to develop s tab ility in m andibular dentures. J P rosthet Dent 16:414 MayJune 1966. von Krammer: SUBLINGUAL EXTENSION ■ 587