A crit ical appraisal of tongue-thrustin g W. J. Tulley, Ph.D., F.D.S., D. Orth., R.C.S. London, England M ny of the present-day view s on tongue-thrusting are reflected i n the early writings of very able clinician s, and their work has to some xtent been ignored. Like many other present-day view s on orthodontics, they have gone through a full cycle, and in the conclusion to this article it will be sepn t,hat there has been an overconcentration on the effect of the soft tissu es on malocclusion. One of the earliest writings is that of Lcf~ulon,~ published in 1839, in which it is obvious that he appreciated t,hat among the causes of irreg ularities of teeth wcrc “sounds of speech in which the t ongu e strikes against the u pper anterior teeth, pushing them forward.” An article by Desirabode,” published in 1843 , is the first traceable refercncc to the fact that the lips on the outside and the t ongue on the inside of the mou th constitute a balance of forces that m ay retain the teeth in their position. In 1859 , Bridgeman” introduc ed the “lateral pressure theory” and described ir- regularities of the teet h due to visincreme~ati (external muscle forces, as that of the lips an d cheeks), visestensionis (internal muscle forces, as that of the tongue), and wisoccZusioS (occlusal forces). King sley, 4 in 1879, made a conside rable study of speech sounds but did not relate movements of the soft tissu es to dental arch form. At the turn of the century, Angle5 recog nized the problems of the musc ular environment of the dental arches but would not accept the fact that in certain cases t,hey might form an insurmountable difficulty in treatment. In the appendix to the seventh edition of Malocclusion of the Teeth, Angle states : “We are just beginning to real ize how common and varied are the vic iou s habits of the lips and tongue, how powerful and persiste nt they are to overcome.” Norman Bennett6 showed a clear understanding of the problem when, in 1914, he wrote: “The muscles of mastication produce conditions of vertical and lateral stress, the U S C of the tongue in mastica tion and speech reacts upon the teeth intern ally, and the lip s an d chee ks in their every movement, even of 64 0
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8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley
W. J . Tul ley , Ph.D. , F.D.S. , D. Or th. , R.C.S.
London, England
M ny of the present-day views on tongue-thrusting are reflected in
the early writings of very able clinicians, and their work has to some extentbeen ignored. Like many other present-day views on orthodontics, they have
gone through a full cycle, and in the conclusion to this article it will be sepn
t,hat there has been an overconcentration on the effect of the soft tissues on
malocclusion.
One of the earliest writings is that of Lcf~ulon,~ published in 1839, in which
it is obvious that he appreciated t,hat among the causes of irregulari ties of teeth
wcrc “sounds of speech in which the tongue strikes against the upper anterior
teeth, pushing them forward.”
An article by Desirabode,” published in 1843, is the first traceable refercncc
to the fact that the lips on the outside and the tongue on the inside of the mouth
constitute a balance of forces that may retain the teeth in their position. In
1859, Bridgeman” introduced the “lateral pressure theory” and described ir-
regularities of the teeth due to visincreme~ati (external muscle forces, as that
of the lips and cheeks), visestensionis (internal muscle forces, as that of the
tongue), and wisoccZusioS (occlusa l forces).
Kingsley,4 in 1879, made a considerable study of speech sounds but did not
relate movements of the soft tissues to dental arch form.
At the turn of the century, Angle5 recognized the problems of the muscular
environment of the dental arches but would not accept the fact that in certain
cases t,hey might form an insurmountable difficulty in treatment. In the
appendix to the seventh edition of Malocclusion of the Teeth, Anglestates : “We are just beginning to real ize how common and varied are the
vic ious habits of the lips and tongue, how powerful and persistent they are to
overcome.”
Norman Bennett6 showed a clear understanding of the problem when, in
1914, he wrote: “The muscles of mastication produce conditions of vertical
and lateral stress, the U S C of the tongue in mastication and speech reacts upon
the teeth internally, and the lips and cheeks in their every movement, even of
64 0
8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley
significant as the resting posture, which w ill be seen to confirm many clinical
observations.
Cinefhoroscopy. Ardran and Kemp,Z4 Cleall,Z” Tulley,‘G and others have
shown that th is technique has limitations in terms of speed and is only two
dimensional. It does not lend itsel f to ser ial studies because, although the dosage
is small using image intensifiers, it is difficult to pcrsuadc patients that it is
clinically necessary.
Cephalometric head films. Peats7 and others have shown the possible dif-
ferences between the relaxed and habitual postures of the tongue and this,
iu turn, has made some contribution to our knowledge. However, this technique
is subject to variation.
Newophysiologic experiments. BosmaZ8 and his co-workers, Grossman,?”
Berry,“ ” and li’awcus,“l have carried out various neurologic tests on the behavior
of the tongue. So far, the use of stereognostic test,s has indicated very considcr-able individual differences in lingual scnsorimotor factors, and I am sure that
this work will continue.
Serid cinephotog,ruphy. This is difficult to a,nalyzc scientifically, but, it
tloes highlight the individual variations. Although cint~photography cannot
display the intraoral movements of the tongue, work by Vhillis32 and ot,hcr
film studies carried out by the Veterans Organization have shown tongue
movements through surg ical defects in the fact. This longitudinal approach
has proved to be of great value, as wi ll be seen later.
It is now much more certain that facial form will dictate function rather
than that function dictates form, as was formerly believed. In an effort to
clarify some of the confusion over ‘itongL~e-tlll’llst.” The author has undertaken
two experiments : (1) an epidemiologic investigation of the incidence of abnormal
tongue function and posture and (2) a longitudina l study using tine films of
patients, with or without orthodontic treatment, some of them extending OCR
3 period of 20 years
Epidemiologic invest igat ions
In this investigation 1,500 Il-year-old school children, a random sample
selected from all socia l groups in southeast and east London, were examined.
Those who had circumoral contraction in swallowing with forward movements of
the tongue and those in whom there was also a forward movement of the tonguein production of t,he ‘ls” sounds in speech, were set aside for further invcstiga-
tion. The tongue had to be suffic iently forward to have the tip placed either
interdentally or under the upper incisal edge.
As by far the most common reference on tongue-thrusting is associated with
Class II, Division 1 malocclusion, 329 of the children (22 per cent of the total
sample) were shown to have some degree of this malocclusion, but only 141
(less than one half) were assessed as requiring orthodontic treatment. Only
43 of the 329 children showed evidence of adverse tongue and lip behavior
which might jeopardize permanent correction of the incisor relationship.
Examining the total sample for the more pronounced type of tongue-thrust,
only 40 of the total sample (2.7 per cent) had the type of tongue behavior
8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley
Fig. 1. Examples of tongue-thrust wi th good occlusion
shown in Fig. 1, and only half of this group hat1 any degree of malocclusion
deserving of treatment. ln fact, 12 of the children with tongue-thrust, and lisp-
ing speech had excellent occlusions (1 I’g. 1) These figures put tongue-thrusting
in its true perspoct,ive.
longi tudina l t ine studies
By examining some 50 patients over a period of nearly 20 years, I have
been able to confirm my previous findings”” and those of Ballard ”’ on the
nature of tongue-thrust. It is possible t,o break down tongue-thrusting into
main categories, but thcrc is also some overlap and it is difficult to produce
a good classification. Investigations over the past 20 years have enabled us to
rnake the following classification, which is not claimed to bc ideal but repre-
sents an attcrnpt to he helpful to the clin ician:
Tongue-thrush~g US CL abit. The fact that this w ill not be seen very com-
monly past the age of 11 years is a reason for delaying treatment where the
facia l pattern is good and there is merely a slight open-bite and increased
ovcrjet with a Class I or Class II relationship (Fig. 2). These patients with
a persistent tongue-thrust habit wi ll be treated quick ly when the labial seg-
ment is put into its correct position. It is quite unnecessary for these childrento be sent for any form of x-educational therapy. Placement of the teeth in
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Fig. 2. A, Example of facial maturation. A habit tongue-thrust was present in associa-
tion with thumb-sucking up to 7 years of age. The incisor relationsh ip developed normally
and the open-bite closed. No active treatment. B, Models from 4 to 19 years.
correct position and the very presence of the appliance will be sufficient.
Although the psychologic aspects of this subject have been ignored, it is inter-
esting to note that I have seen cases in which the lisping speech has returned
for a short time when the child is under stress.
Tongue-thrusting which is possibly endogenous or in&e. In the epidemio-
logic investigation previously described, a familial pattern was evident in 30
per cent of the small group of children who had tongue-thrusting behavior
(Fig. 3). This needs further investigation, and it may be that there is an ob-
scure central variation. This kind of tongue-thrusting is particularly markedin the sibilant sounds of speech and may often be seen in siblings and in one
8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley
of the parents. It can occur when there is a perfectly normal occlusion if there
is a good facial skeletal pattern, and then it is of little significance to the ortho-
dont,ist. If it occurs where there is an adverse facial pattern, it may be a dorn-
inant feature and may place severe limitations on the improvement of theincisor relationship (Fig. 4). In contrast to the simple tongue-thrusting habit,
it wi ll not respond to any kind of therapy.
Tongue-thrust us UTL crduptive behnzGr. The majority of problems which
are of concern to the orthodontist fall into this category. In the Bri tish Isles
and part,s of the United States many patients arc unable to effect an anterior
oral seal with the lips at rest. This does not mean that there is any mouth
breathing. The resting posture of the tongue is more important than its func-
tional movements.
The type of deglutit,ion in which thcrc is a tongue-thrust and excessi\-c
circumoral contraction is due to the fact that there has to be excess ive contra+tion of the labial musculature in cases where the lips arc “incompetent” ant1
the tongue comes forward to complete the anterior oral seal. This tongue-thrust
swa.110~ can change ynitc dramatically if orthodontic t~reatment can ~)lacc the
l i l l j i>ll scgmcnts in goo~l relationship so that the lower lip can COll l ( ’ to seal On
t11c labiai SllI+iIW ;,f the upper i&+isor t Wtll. Ptlilny palients wit,11 ClaSS II,
Fig. 3. Fam i l ia l (endogenous) tongue behavior in two members of a fami ly . Note in -
terarch tongue posi t ion. A, With Class I I dental base. B , With Class I I I dental base.
8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley
Division 1 malocclusion may exhibit tongue-thrust prior to treatment, but this
is not like ly to be a primary problem after treatment.
An adaptive tongue behavior, in which the tongue is not only forward in
functional movement but postured forward over the lower incisors at rest to
seal with the lower lip, is a very important problem. This posture is associated
with an adverse skeletal pattern in which there is a high Frankfort-ma.ndibulal
plane angle.
In the epidemiologic survey, the type of facial pattern found in only 0.6 per
cent of the child population has always been recognized by orthodontists ils
pl’esenting a difficult problem (Fig. 6). It is the one in which tongue-thrust,
;Intl more tspcc ially tongue posture taken into conjunction with t,hc adrc~e
skclc tal form, wi ll produce an anterior open-bite which is very resistant to
I rc~atmcnt. This may be associated with a Class I, II, or III malocclusion.
Pathologic n?zd ~/rossl~~aO?lornlnl tompc 1>roble,lzs. Just as the common mal-ocdclusions arc not due to pathologic abnormalities, the common variations in
tongue function should not be look4 upon as bein g dn c to pathologic entities,
and it is very unlikely that any degree of dysdiadochokincsia has any relc~ancc
to the cliscussion. There is no doubt that tongue size plays some part, but :I
1 iic macroglossia is ext,rcmely ri lre.
A
B
Fig. 4. A, Tongue position in “s” sound before orthodontic treatment. B, One yearlater
then 3 was no interarch spacing during “s” sound. Three months active treatment 01dy.
8/3/2019 A Critical Appraisal of Tongue-thrusting-Tulley