I42 Australian Dental Journal, April, 1963

Habits and their relation to malocclusion*

J. 6. Moffatt, B.D.Sc.

Perhaps the most interesting and possibly the most difficult treatment in the field of orthodontics, is the treatment of malocclusion as a direct result of habit, for the task is two-fold in that the treatment of the cause is just as important as the treatment of the malocclusion itself. Before any attempt is made to discuss treatment, consideration will be given to the histological changes in bone tissue under the stress of such habits, and also to certain factors which contribute towards the habit and thus to the malocclusion itself.

The histological changes that occur in bone tissue under stress are generally known and also that living tissue responds to pressure no matter what its source. However, perhaps many fail to realize that histological changes which may occur when a child sucks his lips, thumb, fingers, or any other object, are exactly the same as those occurring as a result of slow, gentle, orthodontic pressure.

When the pressure is mild and slow, as is the case when a habit is pursued for any length of time, the bone surrounding the teeth on the side away from the origin of the force is first slowly broken down and resorbed. If the habit persists. it will hold the teeth in

* Based on a lecture presented a t the Seventh North Queensland Dental Convention, Mackay, May 23-27, 1960. and illustrated with photographs of a Silent Clinic presented at the First Congress of the Australian Society of Orthodontists, Sydney, August, 1961.

Received for public-ntion April, 1962.

that position and new bone will regenerate and thus support the teeth in their new position.

The periodontal fibres on the side of the teeth from which the pressure originated are a t first stretched and when the habit maintains the teeth in their new position, new bone fills in this area.

The most common of all oral habits is that of sucking, and this not only includes sucking of the thumb and fingers, but also embraces the habit of sucking the cheek, lips, and tongue. The sucking habit can be discussed in three groups, viz.:

1. The infant-birth to 2 years. 2. The pre-school child-2-5 years, and 3. The school child-6-12 years.

The infant-birth to 2 years The natural action for survival in the new-

born babe is sucking, and a baby naturally fed, has to suck vigorously to draw milk from the breast, therefore after a normal feed both his hunger and his sucking instinct are usually satisfied.

According to Massler and Wood(*) “thumb sucking during infancy is not the concern of the dentist and should be of no concern to the parent if no physical effect is produced on the teeth”. On the other hand, since many a dentist is asked his opinion on thumb-sucking during the early stages, perhaps i t is as well

( 1 ) Massler, M., niid Wood, A. W. S.-Thumb- sucking. Am. J. Orthodont., 3 6 : 2, 150-154 (Feb.) 195.0.

Australian Dental Journal, April, I963 I43

to give the opinion of other authorities who pay particular attention to the cause of fist, thumb, or finger sucking in infants.

After a comprehensive investigation into the instinctive nature of the sucking act, A. G. H. L:~wes(2) suggests that a possible cause of this fist, thumb, or finger sucking in infants, even among breast fed babies, is the failure to satisfy fully the sucking instinct through over-hasty feeding, which results in a sufficient amount of food being taken, but insufficient sucking movement.

Davit%@) of New Zealand, when address- ing the 9th Dental Assembly of the Bundaberg Sub-Branch of the Australian Dental Associa- tion (Queensland Branch), paid attention to the cause of thumb-sucking in infancy and spoke along similar lines. In addition he stressed that special care should be taken with artificial feeding to produce as natural a n action as possible, and thus satisfy the sucking instinct as well as the hunger. With respect to this he said that particular care should be taken regarding the size of the teat of the feeding bottle and also the size of the hole in the teat. This should not he too large, otherwise the baby will satisfy his hunger quickly, but will not satisfy his sucking instinct. If the sucking instinct is not satisfied, then sucking of the thumb or fingers will probably result. To control this extra sucking, Davies suggested:

The size of the hole in the teat should be as small as is practicable in order that the child will get the necessary amount of jaw exercise to stimulate growth and development, and also satisfy his sucking instinct. If the sucking of the thumb or fingers persists, a teething ring should be substituted but a n effort must be made to achieve this without the child realizing that the thumb or fingers have been taken away.

Davies expressed the opinion that this extra sucking during infancy was probably due in the 1-2 age group to a diet deficiency,

IA~Lawes. A. G. H.-A usvchosomatic studv into the nature, preveniion and treatment of thumb-sucking and its relationship t o dental deformity. Part 111. D. J. Australia, 2 2 : 6, 272-305 (June) 1950.

(;I) Davies, G. N.-Address to 9th Dental Assembly Rundaberg Sub-Branch, Australian Dental .Issociation (Q’ld. Branch), 20-22nd May, 19.57. Unpublished.

and seemed to be more noticeable in the child that had not had the benefit of breast feeding, or had only had a small percentage.

Shultis“) contends that “since dentists can- not predict in which children the habit will persist, each and every thumb-sucker must be regarded as a possible case of malocclusion in the future”. He also points out that correction of thumb-sucking in infants is fundamentally psychological and should be approached as such. The baby should be sufficiently nourished and tenderly fondled so that he feels satisfied, secure and wanted. A “snuggle bunny” tied securely to the bars of the crib will provide company and distraction.

Therefore, so far as the control of sucking in this age group is concerned, the main emphasis seems to be upon a correct feeding routine, care being taken to ensure that this routine is balanced so far as nutritional, sucking, and emotional needs are concerned.

Also, when the deciduous teeth appear, the introduction of solids into the diet will play a n important part in directing energy towards chewing activities, and this in turn will contribute towards the normal growth and development of the teeth and jaws.

The pre-school child (%5 years) By the age of 2 years, the child has

emerged from babyhood and his mental com- plex is dependent to a large extent upon environment and the judgement of the parents. Most children have a tendency to imitate and particularly do they imitate those with whom they have close contact. For instance, a child may acquire a muscle tic by imitating a similar spasm that may be present in another member of the family or even in a playmate. These spasms are easily acquired but very difficult to eradicate. Therefore preventive measures cannot be too strongly stressed because of the pernicious possibilities of such habits if they are ignored.

Regarding the sucking habit i n this age group, Weber@) states “in some, the sucking act is practised to excess and is not dis- continued as is usually the case, by the age of two years. The persistence of the habit

( 1 ’ Shultis, W. K.-Habits, saboteurs of occlusion. J. Canad. D. A., 15: 9, 473-479 (Sept.) 1949.

( 5 ) Weber. F. N.-Prophylactic orthodontics. Am. J. Okthodont., 35: 8, 611-635 (Aug.) 1949.

I44 Australian Dental Journal, April, I963

beyond the time of eruption of the permanent central incisors is often attended by mal- occlusion. Rather than take a chance on self- correction, even though the odds are in favour of it, we believe that early interception and eradication of sucking habits are the safest and wisest policies”.

Massler and Wood“’ contend that “when thumb-sucking continues beyond infancy, we must regard the act as a symptom of some psychological difficulty and treat the cause rather than break the habit”.

Orthodontists have been widely criticized by psychiatrists for their attempts to break thumb-sucking habits, most psychiatrists main- taining that thumb-sucking is merely one symptom of disturbed psychic balance. While agreeing with this theory that thumb-sucking is merely one symptom of disturbed psychic balance, one weakness in the psychiatrists’ approach is that they do not grant that a habit, once established, may persist even if the original causative factor no longer exists. Therapy, therefore, should be towards cor- rection of the total situation, not merely the habit, for physical or mechanical restraint too early is not desirable. Home care by the parents is most important, therefore the utmost tact by the dentist in his efforts to treat the cause is essential.

Specific means for re-directing the child’s energies should be found, and in this respect kindergarten training provides an excellent avenue. A careful watch for the habit can be kept by both mother and teacher, and when the child has the tendency to practise the habit, occupational therapy with the hands should be encouraged. At bedtime, the child should be given a favourite cuddly toy.

The school child

Habits in children above the age of 6 years should receive more serious consideration for various types of malocclusion may be caused if these habits persist.

For instance, two types of malocclusion may result from thumb-sucking. First, if the hand is held upright during sucking the relation- ship of the jaws remains normal with only a labial tipping of the maxillary incisors. Secondly, if the hand drops during sucking, the back of the thumb rests on the mandibular incisors while the palmar surface of the thumb exerts a labial pressure on the maxil-

lary incisors and the alveolar process, with the result that the process, as well as the teeth, is moved forward. An open bite often results from this habit.

Regarding the open bite as a result of habit, care should be taken to recognize which habit has caused the open bite, for an abnormal swallow can produce a n effect upon the anterior teeth similar to that of thumb- sucking.

If the tip of the tongue assumes when swallowing a position against the palatal surface of the upper anterior teeth, a n abnormal force is exerted in a n outward direction, and if over a period of time, this force occurs every time the patient swallows, a protrusion of the upper anterior teeth will result.

Factors contributing towards this abnormal swallow are:

1. When enlargcd tonsils are present, the patient when swallowing, attempts to open the throat.

2. When deciduous anterior teeth are missing, the patient when swallowing, closes with the tongue the space pre- viously occupied by the deciduous anterior teeth.

An open bite can also be further aggravated by tongue sucking because a t rest the tip of the tongue lies between the upper and lower teeth. This is closely associated with tongue biting.

Further habits associated with thumb- sucking that may often modify, or accentuate, the malocclusion, are mouth breathing, open bite, lip biting, lip sucking, cheek sucking. Allied with thumb-sucking are accessory habits, such as hair pulling and skin scratching to the point of causing pain. Medical care is advisable in these advanced cases.

Mouth breathing

Mouth breathing in young children is frequently observed, but i t does not neces- sarily follow that all children who have a tendency to hold the mouth open, breathe exclusively through the mouth. There are, of course, cases of children who do breathe exclusively through the mouth, but there a re also some who hold the mouth open and breathe through both the mouth and the nose. Mouth breathing is usually a result of bony

Australian Dental Journal, April, I963

growths in the nasal a i r channels, adenoid tissue, allergies, or where normal closure of the lips is impossible due to malocclusion.

Waring@) has said “the establishment of mouth breathing from whatever cause is a true danger point. I t is accepted as a fact by all physiologists that disuse of any part or organ of the body brings in its train progressive loss of function with degenerative changes in all tissues. The side tracking of nasal passages and accessory sinuses in the phenomenon of respiration must never be permitted”.

Certain characteristics are indicative of mouth breathing:

145

1.

2. 3. 4.

5.

6. 7.

8. 9. 10.

A narrowing of the maxillary arch and possibly the mandibular arch as well. Protrusion of the maxillary incisors. Supraversion of mandibular incisors. Lack of vertical development in the pre-molar and molar area. Distal relationships of the mandible to the maxilla. Short underdeveloped upper lip. A thickened lower lip, which has a tendency to roll outwards. Underdeveloped nostrils. Lack of tone of the facial musculature. A preoccupied expression.

Cheek and lip sucking Sucking of the cheek and lips is less common

than thumb-sucking, but if practised long enough may contribute towards malocclusion. The cheek may be sucked in and held between the bicuspids and molars and biting of the cheek may accompany this action. This habit may result in either an open bite on each side, or it may cause a narrowing of the arches by tipping the bicuspids and molars lingually.

Lip sucking is frequently observed, the resulting malocclusion depending upon which- ever lip is sucked. When the upper lip is concerned, the maxillary incisors frequentIy become locked lingually to the mandibular incisors. When the lower lip is sucked a twofold result may occur. The maxillary incisors may tip labially, while the mandibular incisors may be tipped lingually.

In lip biting, if the upper lip is bitten lingual tipping of the maxillary incisors will

(8 ) Waring. A. J.-Some interesting data in the pediatric field. Am. J. Orthodont. & Oral Surg., 2 5 : 7 , 651-656 (July) 1939.

-~

probably occur. If the lower lip is concerned, labial tipping of the maxillary incisors will probably result. If the left and right sides of the lower lip are bitten alternately, rotation of the maxillary central incisors will in all probability result.

Cross-bite malocclusion as a result of propping and pillowing habits is quite often observed in patients who apply pressure by the hand or fist to the outside of the face, the teeth affected being those in the area where the pressure is exerted. The pillowing habit is observed in the child who sleeps on the stomach, using the hands as a pillow.

Malocclusion as a result of posture pressure is usually caused by the child always lying in the same position while sleeping. However, Fluhrer‘?) in a n investigation of pressure habits as aetiological factors in malocclusion, showed by motion picture camera, operating automatically while the child was asleep, that the average child turned, over twenty times in a night.

A Class 111 malocclusion is quite a n easy one for a child to acquire by imitation, especially if such a malocclusion exists in the same family. I f the imitation is practised at the time of eruption of the permanent incisor teeth so as to cause the maxillary incisors to pass lingually to the mandibular incisors and so become locked in that position, a Class I11 malocclusion will invariably result.

Another critical time so far as the acquisi- tion of habits is concerned, is that time in a child’s life when teeth come and go. During this time, when tooth eruption is imminent, it has been observed that some children have a tendency to develop such habits as cheek biting, lip biting, and the habit of swinging the jaw from side to side. This latter tendency can develop into a left lateral or a right lateral swing.

Treatment As Johnson(s) has observed, whenever habit

is a contributing factor in malocclusion, treatment is a n individual problem, because there is variation in the performance of the habit, in the urge behind it, and hence i n the treatment.

(7) Fluhrer, A. V.-Some original investigaticaur into pressure habits a s etiological factors in dentofacial abnormalities. Am. J. Orthodont.. 3 6 : 37 -57 (Jan.) 1950.

(8) Johnson. L. R.-Habits and their relation 11, malocclusion. J.A.D.A., 3 0 : 11, 8 4 8 - 8 5 2 (June) 1 9 4 3 .

146 Australian Dental Journal, April, I963

Therefore, it will be appreciated that before treatment is commenced a careful study of the child is necessary, for each child will have his own physical and emotional characteristics and consequently each child will have his own particular limitations. The attitude of the parents must be carefully studied, for cooperation in the home by both parents and child is most necessary and the end result depends to a great extent upon this aspect of the treatment. Thus, therapy must be directed towards correcting the total situation.

Three general types of therapy may be employed to correct habits, viz., psychological, chemical, and mechanical, and as an adjunct there is hypnosis.

Fig. Ia-Progress and original models (note in original models that thc bite has heen raised 1 mm to allow the oral screen to he accom- modated more effectively in the mouth). Case 1

Fig. 2n.-Original and 11rogreax models. Case 2.

Fig. 2 b.-Demonstration model showing remov- able “hay-rake” inserted to correct finger- sucking habit. Gauge for Adams clasps-

2 1 B. & S. Gauge fo r tines-19 H. R- S .

to bring the habit into the consciousness of the child so that the satisfaction and pleasure derived from the habit may be reduced.

Chemical therapy embraces the use of hot- tasting or bitter-flavoured preparations on the fingers or thumb in an endeavour to keep them out of the mouth. This is only success- ful when the habit is newly acquired.

Fig. ib.-Mo&ls prepared‘ for construction of oral screen and wax model of oral screen. In children who have not thrown off the

habit of finger or thumb-sucking by the time Psychological treatment is probably only they have reached the age of six years,

successful in the older patient. The habit is mechano-therapy is indicated, for by this time intentionally practised in front of a mirror all the simpler methods such as Anger stalls, ( the Dunlap method), the patient being forced adhesive plaster on fingers and mittens sewn t o concentrate on the performance i n order into the sleeping garments to prevent flexion

Australian Dental Journal, April, I963 147

Fig. 3o.-Original and progress models. Case 3 .

Fig. 3b.--Fixed “hay-rake”. Gauge for arch wire-19 B. & S. Gauge for tines-19 B. & S.. and dimensions of posterior bands - 3 ’16” x 2” x 0.004” stainless steel. Tines are attached to the lingual bar first by one turn of the wire, then soldered ; therefore should the solder be disturbed the tine will still remain loosely attached to the bar until repair can be effected. The extremity of the tine i s looped and the loop is then filled in with solder.

h70te also the open cleat on the lingual sur- face of the band on the This cleat is left open until the bands have been inserted; it is then closed and thus the anchorage is

completed.

.of the arm have usually proved futile. How- ever, before discussing fixed appliance therapy, I would like to mention those patients who practise thumb-sucking only when going to sleep and need just a little encouragement to help them throw off the habit completely. For a boy, the best method in my opinion, is the use of boxing gloves. First, they make hini feel manly, then from a humane point of view they are harmless and provide freedom for the child, and thirdly they are very effective for they cannot be removed.

Another very effective method for night sucking for children in this category is the oral screen which is worn in the vestibule of the mouth while sleeping (Fig. l a ) . The removable “hay-rake’’ is useful, but only in selected cases (Fig. 2 b ) .

Fix. 4rc.---Prcix1’ess and original models. Case 4.

Fig. 4b.-Fised “hay-rake”. Gauge of arch wire-19 B. ((r S. Gauge of tines-19 B. & S. Posterior li:tnd-:; 11;” x 2“ x 0,004” stainless

s t rc.1.

In cases where thumb-sucking has become firmly established and there is definite evi- dence of nialocrlusion as a result of the habit, an intra-oral device is indicated. Perhaps the most successful appliance for these children is the fixed “hay-rake’’ (Figs. 3 b and 4 b ) . This consists of a palatal bar cemented to the teeth by single or double bands. Attached to the palatal bar are a series of tines which act as a fence, and this not only prevents thumb-sucking, but tongue thrusting as well.

Another useful fixed appliance is that which embodies the palatal bar cemented to the teeth by single or double bands, but instead of the tines a “wire cage“ is incorporated across the palate. This type of appliance is indicated for patients in which the tongue thrust is not quite so severe (Fig. 5 b ) .

Naturally, after appliances of this nature have been inserted, strict attention to diet is essential and cooperation by the mother and child is very necessary. The first week after treatment is commenced is usually a critical time, and a great deal of patience, tact, and understanding on the part of the operator and parent are necessary. The child will miss the comfort of sucking most when going to bed, therefore a sedative on retiring is wise

I48 Australian Dental Journal, April, I963

for the first night a t least. However, it i s amazing how a child will cooperate after i t has been explained that the treatment has

Vig. 5rr.-l’rojiress ;ind original models. Case 3 .

Fix. :,b.--I.’ixecl “(,age”. Gauge for cage- 1 9 B. & 9. Posterior b:inds-:l/l6” A 2” x 0.004” stainless steel. In the construction of this cage each wire is first Ioo!>ed around the adjacent wire once and then soldered, and this method is repeated when at taching the cage to the arch wire. Thus, should the seal of the solder be disturbed, the cage is still held in position until repair can be effected. S o t e here also

the open cleat OP the bands on the DID.

been designed simply to help him overcoine something which other children do not normally do.

A common method employed to break lip biting and lip sucking habits is the insertion of a band with a sharp labial spur, this band being cemented to a mandibular incisor tooth. The purpose of the appliance is to prick the lip gently every time the child attempts t o continue the habit. A similar appliance will also correct cheek biting (Fig. 6 ) .

To control propping and pillowing habits, a very effective appliance is one which has as a base a Hawley appliance, attached to which is a buccal cage (Fig. 7) .

Tongue habits such as thrusting and biting, may be broken by the insertion of a non-

__

Fig. ri.-~~i)enionstration model showing band and spur to correct lip biting habit. Band- stainless steel Q” x 2” x 0.004”. Spur-gauge

1 9 n. M s. This appliancr is worn for three tci fou r

months and is activated slightly each fortnight. the method of activation being to move the “spur” towards the l i p ; thus when the habit is practised the lip is gently pricked a s :L reminder. If the appliance is not act ivat td the patient Ivill become accUStOl~led to it tinct

the habit w i l l continue.

removable “hay-rake” as described previously. The patient must also be taught to swallow correctly, and the following exercise is use- fnl to promote normal swallowing. A small

Fig. i.-Demonstration model showing a buccal cage attached to a Hawley apDliance to correct propping and pillowing habits. Gauge for cage- 1 9 B. M s., and for circumferential clasps-

1 9 B. & S. This appliance is worn both day and night

but removed when eat ing and cleansing the teeth, and in the event of playing strenuous sport. After the appliance has been worn for several days the sof t cheek tissues become tender while the habit is being practised; thus the satisfaction derived from the habit is reduced considerably. Treatment time-three

to fou r months.

piece of glucose jube is placed on the palate just back of the central incisors, and the patient is taught how to hold i t there with the tip of the tongue. As the glucose dissolves, the tongue is held in this position while swallowing occurs. I t is important that t h e

Australian Dental Journal, April, I963 I49

glucose be well forward or it will be held in the palate by the dorsum of the tongue, the tip being left free to operate as always, thus defeating the purpose of the exercise.

In the treatment of mouth breathing, as Salzman(g) points out, "before nasal breathing can be encouraged in mouth breathers, it must be ascertained that it is possible for the child to breathe through the nose".

Johnson(&) has said that "treatment of this habit requires the removal of any nasal obstruction and breaking of the mouth breath- ing habit as soon as orthodontic treatment has progressed far enough to reduce the protrusion of the incisors so that the lips can be closed without too much effort. Most of the patients use the lower lip almost entirely in closing the lips, and this results in the overdevelopment of the mentalis muscle, whirh is very troublesome and must be over- come to assure the success of treatment. In instructing the patient in exercises to teach normal breathing, it is essential that the mentalis muscle be controlled. To accomplish this, the patient grasps the chin between the

'(') Salzman, J. A.--1'rinciples of orthodontics. Philadelphia, J. I:. Lippincott Co., 2nd ed., 1950 (P . 6 6 4 ) .

11"' Strang, R.--Textbook of orthodontia. Phila- delphia. Lpn & Fehiger. 3rd ed., 1 9 5 0 (p. 1 7 3 ) .

thumb and forefinger and holds the lower lip down, while the upper lip is forced to come down to meet the lower when the lips are closed. This should be done several times, three or four times daily. To augment the effect, the patient should be taught to whistle. Whistling not only causes the mentalis to function as desired, but also develops the orbicularis oris and the associated muscles and the muscles controlling the alse nasi".

Perhaps the best method to correct mouth breathing is the oral screen, worn at night, and in addition to this, nasal breathing should be practised after strenuous exercise.

In conclusion mention should be made of the value of the psychological approach to the child. There is no substitute for the child's voluntary cooperation and this can only be gained by kindness, tact, and patience, plus the ability to be completely relaxed oneself. Also, what Strang("') has described as "the four important controlling factors of child conduct, viz., praise, blame, reward, and punishment" do play an important part in case management.

A.M.P. Building, Corner Queen and Edward

Streets, Brisbane.