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The general objective of orthodontic treatment with any technique is to obtain a result that simulates normal occlusion in so far as practicable with the malocclusion at hand and the appliance employed for its correction. With the Begg technique, although all individual and group tooth movements toward this over-all objective are carried out simultaneously and as promptly as possible, the treatment is divided into three stages, each of which has its own integrant objectives and movements.

The objective of orthodontic treatment is to correct malocclusion of the teeth and those deformities of the jaws and face associated with it. "Normal" occlusion has come to imply not only correct occlusion of the teeth but also that all of the structures of the dental apparatus are anatomically and functionally correct and in harmony with the correctly occluding teeth. He devised a concept about optimal force levels and efficient force distribution, using his wire for arches as well as auxiliaries with a modification of Angle's ribbon arch bracket, and called it "the light wire differential force technique."



Begg discarded the concept of “textbook normal� occlusion as a fallacy and therefore as a hindrance to progress in orthodontics and dentistry generally. He adopted stone age man attritional occlusion as the basis of orthodontics, because it is the anatomically and functionally correct occlusion. He said that the production and maintenance of correct, wellfunctioning, healthy and esthetically acceptable occlusion must be the aim not only of orthodontists but of all dental practitioners.

Correct occlusion is not the static condition that it is held to be in the concept of “ textbook normal� occlusion. In correct occlusion the positional relationships of individual teeth to each other in the same dental arch, the occlusal relationships of the teeth of one dental arch to those of the opposite arch and the relationships of the teeth to the jaws change continually throughout life. Therefore the only constant in correct occlusion is continually changing occlusion. Correct occlusion is not a fixed or particular anatomic state, but a changing functional process undergoing continual modification and adjustment during the whole life of both deciduous and secondary dentitions.

The study of Stone Age dentitions was carried out on skulls of Australian aboriginals who died before the white man came to Australia. Australian aboriginal skulls were used for this study not because the development of attritional occlusion of their teeth differed from the development of attritional occlusion of Stone Age man’s teeth in other parts of the world, but because such skulls were more readily available than the skulls of other Stone Age people. By studying Stone Age dentitions, not only the development of correct occlusion is revealed but also the etiology of many of civilized man’s malocclusions.

Anatomically correct occlusion can develop only when there is sufficient attrition of the teeth for them to assume correct occlusal relationships. Stone age man's teeth have occlusal and proximal attrition. Often this is so marked that dentin is exposed occlusally, incisally and proximally. “Textbook Normal’’ occlusion in civilized man is anatomically incorrect, because his food is too soft and concentrated to cause tooth attrition. The incisal occlusal, proximal and axial relations of civilized man’s teeth remain almost static throughout life, because the unworn cusps are firmly locked in what are erroneously but almost universally regarded as anatomically correct occlusal relations. Also, the almost static positions, especially the mesiodistal, of civilized man’s teeth in relation to his jaws are not anatomically correct.

Civilized mans jaws are prevented by unworn teeth from assuming correct relations to each other in all directions, especially the vertical.

With reference to the vertical direction, civilized man’s upper and lower jaws are forced farther and farther apart as his teeth continually erupt without being continually reduced in vertical length by occlusal and incisal attrition.

High unworn tooth cusps are wrongly considered to have evolved in man to maintain stability of occlusion throughout life. The only true advantage of high cusps is that they help to guide the teeth into their occlusal relationships when the teeth are erupting, and then to hold them in these relations for only a short time after their eruption. Thereafter, unworn tooth cusps prevent the development of continually changing anatomically correct occlusal relations.

Two factors in anatomically correct occlusion • Tooth migration • Changing anatomy of teeth

Tooth migration A physiologically basic factor which is indispensable for bringing about the continually changing positions of the teeth in the jaw bones. Teeth continually move throughout life in two directions simultaneously - horizontal (mesial migration) and vertical (continual eruption).

In the available orthodontic literature mesial migration of human teeth is regarded not as being essential to the maintenance of proper occlusion but as an aberration, a perversion which arises from the socalled anterior component of forces. It is considered to play no role other than to produce malocclusion. On the contrary mesial migration is undoubtedly a quite normal and vitally necessary physiologic process, related to and part of the process of continual tooth migration.

Changing anatomy of teeth The anatomic forms of the teeth begin to change soon after eruption because of wear or attrition. This tooth wear chiefly takes place occlusally, incisally and proximally. Absence of attrition in man causes malocclusion of dentitions which would be free of malocclusion and irregularity of the teeth in the presence of the amount of attrition that occurs in stone age man.


Causes Of Stone Age Man’s Tooth Attrition The food of Stone Age man was hard, coarse, fibrous and gritty. He did not know how to refine his food and reduce it to a soft, pappy consistency before eating it. His food contained much more indigestible bulk and roughage than civilized man’s food. He had to eat larger quantity of food than we do in order to sustain himself. The nature of his food required him to spend more time eating and to expend more force in mastication. Therefore extensive and rapid occlusal and proximal attrition developed throughout the life of his deciduous and perma­nent dentitions.


When stone age man's deciduous incisors first erupt, an incisor overbite develops, just as it does at this stage in civilized man. As stone age man’s deciduous teeth erupt and occlude, attrition immediately commences the process of reduction in the size of each tooth, occlusally, incisally and proximally. As the occlusal surfaces of the deciduous molar crowns are worn flat, the restriction or movement caused by the original cuspal locking disappears. The upper and lower deciduous dental arches are thereby unrestricted in their masticatory movements.

As attrition progress, all of stone age man’s lower deciduous teeth move forward en mass in their occlusal relations with the upper deciduous teeth. With this change in occlusal relations, the original deciduous incisor overbite gradually disappears. Incisors assume a complete edge –to -edge bite soon after all of the deciduous teeth have erupted.

This forward movement of the occlusal relations of stone age man’s lower deciduous dental arch, relative to the upper causes the distal surfaces of the lower second deciduous molars to assume positions farther mesially than the distal surfaces of the upper second deciduous molars.

Absence of attrition of civilized man’s deciduous teeth prevents the forward movement of the lower deciduous teeth and hence the forward movement of the whole of the lower deciduous dental arch, relative to the upper. Thus, the overbite of the deciduous incisors persists until they are shed. This absence of “attritional� forward movement of occlusal relations of civilized man's lower deciduous dental arch, relative to the upper frequently prevents the lower first permanent molar from erupting far enough mesially.


When stone age man’s upper and lower first permanent molars erupt, they can more easily assume their well-known occlusally correct relation because of the change in occlusal relation of the deciduous teeth. Occlusal attrition causes the occluso-cervical heights of all stone age man’s deciduous teeth to be reduced, so that the distance between the upper and lower jaws is less than it is at this stage in civilized man’s non attritional occlusion.

Therefore, stone age man’s upper and lower first permanent molars have less distance to erupt before occluding with each other than do civilized man’s.

Because of extensive proximal attrition of the deciduous teeth and their proximal contact being maintained by the process of continual mesial migration, the overall mesiodistal lengths of the upper and lower deciduous dental arches are considerably reduced.

Civilized mans’ first permanent molars are forced to erupt too far distally in the jaws, and after eruption are still held too far back by absence of proximal attrition of the deciduous teeth.

Shallow glenoid fossa and flat head of mandibular condyle During the period of development of stone age man's deciduous dentition the glenoid fossa is shallow and the head of the condyle is relatively flat. Therefore, lateral mandibular movements during mastication are extensive and wide.

On the other hand civilized man’s glenoid fossa at this stage of development is smaller and deeper and condylar head is also smaller and more rounded and fits up farther into the glenoid fossa. So that the range of mandibular excursions is more restricted.

When stone age man’s permanent incisors first erupt there is an overbite, just as there is throughout life in civilized man. However, mastication of hard, coarse, fibrous and gritty food soon causes stone age man’s permanent incisors to wear incisally at first at an oblique angle.

The obliquity of the plane of attrition of the incisal edges at first points downward and forward.

This obliquity is gradually reduced as more attrition takes place, the crowns of the lower incisors inclining more labially. Ultimately the plane of attrition of the upper and lower incisors becomes horizontal and an edge – to- edge occlusal relationship of stone age man's upper and lower permanent incisors is established in just the same manner as the relations of his deciduous incisors change from the initial overbite to the edge-to-edge bite.

Therefore, stone age man’s curve of spee is not nearly so curved as in “textbook normal” occlusion. It is usually almost a flat plane mesiodistally. Campbell (1925) first showed that stone age man’s overbite of the permanent incisors changes during adolescence to the edge-to-edge bite.

The “cutting” or incisal edges of stone age man’s upper and lower permanent incisors are changed by attrition into flat occlusal surfaces. The elimination of the incisor overbite freely permits stone age man’s lower permanent incisors to tip labially to their anatomically correct position. On the other hand the persistence of the incisor overbite throughout life in civilized man causes the lower permanent incisors to be held in anatomically and functionally incorrect upright positions. Also, the persistence of the incisor overbite in civilized man forces his upper permanent incisors to remain in anatomically and functionally abnormal labial position, whereas the elimination of the incisor overbite in stone age man permits the upper permanent incisors to assume more vertically upright axial inclinations.

During the transitional change from stone age man’s incisor overbite of adolescence to the adult edge –to-edge bite, the premolars, canines and second permanent molars erupt, and occlusal and proximal attrition of these teeth immediately commences. As all of stone age man’s teeth wear proximally, they maintain contact by mesial migration. Thus, instead of there being proximal point contact of teeth as there is in civilized man, large surfaces of neighboring teeth that are continually increasing in area are in contact with each other. Therefore the amount of space required in each jaw to accommodate the teeth gradually becomes less as proximal and occlusal attrition proceeds.

Before stone age man’s permanent canines erupt, proximal attrition and the maintenance of proximal contact of the teeth bring about a mesiodistal reduction of the total width of the four permanent incisors and also of the first and second premolars. There is slightly less space for eruption of canines if the second deciduous molars have not been shed before the permanent canines erupt.

Therefore, the permanent canines have much more space in which to erupt than if attritional mesiodistal dental arch reduction had not occurred.

Also, the distal surface of the first permanent molars and the mesial surfaces of the second permanent molars commence to wear as soon as these teeth erupt.

Early attritional reduction in the overall lengths of the dental arches prevents the development of crowding, overlapping, rotation and bimaxillary protrusion of the six upper and lower permanent anterior teeth as well as irregularity and crowding of the premolars, all of which would inevitably occur in the absence of attrition.

This attritional reduction in the length of the dental arches leaves more spaces at the distal ends of the dental arches for the eruption of the third permanent molar. In this process of attritional mesial migration, the central incisors migrate least of all but the second permanent molars migrate over a longer distance than any teeth that have erupted up to this stage, a distance equal to the sum of the attrition of all the teeth mesial to them.


The eruption and coming into occlusion of civilized man's third permanent molars are often prevented or so retarded or made so difficult by the absence of tooth attrition and by the subsequent inability of all of the teeth mesial to the third permanent molars to migrate mesially. This abnormal holding back of civilized man's third permanent molars too far distally in his jaws is a main cause of the high incidence of his third molar impactions. It is also responsible for the apices of the roots of civilized man’s third permanent molars being closed and their roots being fully formed before eruption.

In stone age man with anatomically correct attritional occlusion, the third permanent molars usually erupt within a year or two after the eruption of all other teeth of the second set.

Two phenomena that support the contention that attritional occlusion is the natural and proper occlusion for man: ď ś The third molars are the only teeth that have their root formation completed before eruption in civilized man's non attritional dentition. ď ś The third molars conform to the behavior of all other human teeth by erupting before complete root formation in the attritional dentition of stone age man.


The amount of reduction in length by tooth attrition of the lower dental arch prior to the eruption of the lower third permanent molars taken in 1930 on the large collection of Australian aboriginal skulls and teeth at the south Australian museum. Averages of mesiodistal width measurements of lower unworn permanent teeth of Australian aboriginals

Averages of mesiodistal width measurements of permanent teeth having inter proximal attrition

The difference between the two sets of measurements is 5.28 mm. This measurement represents the reduction on only one side of the mandible at this stage. Therefore, even before the eruption of the third permanent molars the average reduction of the length of the whole dental arch from the distal surface of the second permanent molar on one side to the other side is 10.56 mm. The amount of attritional reduction in the length of the upper dental arch at this stage is only about 1 mm less than in the lower dental arch.

Murphy (1964) has studied attrition in older Australian aboriginals. He worked on 90 Australian aboriginals skulls in Britain and has produced valuable evidence that attrition occlusion is the correct pattern for the human dentition. His work has confirmed that measurements on the mandibles of young Australian aboriginals are conclusive in their implications concerning the part played by proximal attrition and associated mesial migration in the development of the human dentition.

For descriptive purposes Broca has divided occlusal and incisal attrition into four stages: First stage- enamel worn without cusp obliteration or exposure of dentin. Second stage- cusps worn down and dentin exposed. Third stage – a further stage in which quite an appreciable amount of the crown of the tooth is worn away. Fourth stage – an extreme stage in which most of the crown has disappeared and the wear has extended to the neck of the tooth.

Occlusal and incisal attrition Occlusal and incisal attrition of the teeth also plays an important part in this reduction. The greatest mesiodistal diameters of the crowns of unworn teeth are at their contact points. The contact points of posterior teeth are closer to their occlusal surfaces than to their neck. The points of contact of the lower incisors with each other are at of close to their incisal edges.

After occlusal attrition has extended farther gingivally than the original points of contact of the unworn teeth, the greatest reduction in dental arch length is not due to proximal attrition, it is due to occlusal and incisal attrition, because unworn teeth become mesiodistally narrower toward their necks.

Forward shift of lower permanent dental arch in relation to upper

As the cusps of the permanent teeth are wearing away and the edge-to-edge incisor bite is becoming established all the lower teeth move forward relative to the upper teeth so that the molars, premolars and canines eventually assume typical Angle Class III occlusal relations. This attritional occlusion despite its Class III occlusal relations of the teeth is the only anatomically correct occlusion.

Occlusal attrition and vertical dimension of the face

As occlusal attrition becomes more pronounced, the vertical distance separating the alveolar bone of the upper jaw from that of the lower jaw does not usually become less in stone age man, because the upper and lower teeth are continually erupting thus compensating for attritional occlusion. In contrast to this, the distance separating the tooth bearing part of civilized man's lower jaw from that of his upper jaw becomes greater as he grows older because he does not have occlusal attrition. However, he retains the process of continual tooth eruption which he inherits from his stone age ancestors.


Whether there is an optimum orthodontic force that will give best results , move the teeth at most favorable rate and with least tissue damage and pain? Whether tooth moving force should be applied continuously or intermittently? Storey and smith concluded that there is an optimum range of force values that produces a maximum rate of distal movement of canines, and this optimum force did not produce any deleterious movement of the molar anchor unit.

Differential is defined as the difference of two or more motions or pressures. Tooth movement = force x time resistance The amount of force required to move teeth is in positive ratio to the surface area of the tooth root attached to the bone by the periodontal membrane. The ratio of area of contact of tooth roots with bone in the canine and molar is approximately 3:8.


In an interdental force system (one that uses no auxiliaries, such as headgear and bite plates) the only appliance forces are those exerted between one or more teeth and one or more other teeth. In keeping with Newton's third law, these forces can only be equal and opposite. They are differential only in that they are exerted in opposite directions.

When these forces are exerted, they encounter tissue resistance, and it is tissue resistance that exhibits the differential response to equal and opposite forces which results in differential tooth movement.

Simple crown tipping, for example, encounters little resistance and responds rapidly, but root tipping or bodily movement meets with high resistance and responds slowly.

In the first two stages of treatment, Begg uses the principle of differential resistance when he opposes crown tipping and other low-resistance, rapid-response movements of the anterior teeth against bodily or highresistance, slow-response movement of the anchor molars. This manipulates force and time to conserve anchorage because (a) the light force (about 2 to 2½ ounces) is adequate to overcome the low resistance of the anterior teeth but is less effective against the high resistance of the molars and (b) within this time period (about 10 to 12 months) more of the rapidly responding anterior tooth movements will occur than the slowly responding movements of the anchor molars.

In the third stage, Begg uses equivalent resistance when he opposes the high-resistance, slow-response movements of anterior torquing and paralleling against the high-resistance, slow-response movements of the second premolars and molars.

However, although the resistances and responses are equivalent in type, they are seldom equal in magnitude, and it is in this third stage that most anchorage loss occurs.

When Begg adopted the principle of differential resistance for tooth movement in the first two stages, he took advantage of the significant difference between the types of resistance used and the amounts of force required to overcome them.

For example, Begg noted that Storey and Smith used 150 to 200 grams (5.3 to 7.1 ounces) of space-closing force on each canine to retract it bodily.

In 1961, however, he stated that only 60 to 70 grams (2.1 to 2.5 ounces) was required on each side to tip all six anterior teeth posteriorly. Thus, by employing differential resistance instead of equivalent resistance in the first two stages, he tips all six anterior teeth backward with only 37 per cent of the force Storey and Smith needed to retract the two canines bodily. Furthermore, 60 to 70 grams is only about 20 to 23 per cent of the 300 grams of force reported by them as the minimal required for mesial molar movements.

To sum up, in an interdental force system where forces are exerted only between one or more teeth and one or more other teeth, in keeping with Newton's third law, these forces can only be equal and opposite. Differential force has acquired a broader meaning which may be stated as follows: Differential tooth movement is brought about by the use of differential resistance to equal and opposite forces; equivalent movement is brought about by equivalent resistance to these reciprocal forces. To enhance beneficial movements and to conserve anchorage, differential resistance is used in preference to equivalent resistance as long as practicable during treatment.


A diagnosis that acknowledges that the primitive process of mesial migration and vertical eruption of the teeth can persist in civilized man combined with treatment objectives that include the overcorrection of all mal-relationships. These considerations above all are the key stone of successful treatment.

Simultaneous movement of each tooth toward its final position in dental arch including rapid elimination of incisal and cuspal interferences. The maintenance of the new relationships throughout the treatment promotes post treatment stability.

The total separation of root moving forces from arch wires is carried out during 3rd stage of treatment. Torquing auxiliaries are utilized for buccolingual root movement and individual uprighting springs are used for mesiodistal root positioning. The arch wires are relatively large in cross section to maintain previous vertical and horizontal corrections and to withstand reciprocal forces from the root moving auxiliaries.

Application of the proper elastic forces to create the desired differential movement of teeth. The amount of force needed to move teeth along their paths of least resistance toward their normal positions in the jaws is so light that it can be generated and controlled intraorally. Intermaxillary forces can vary from 2 to 3 oz and intramaxillary forces can vary from 2 to 10 oz depending on whether large rooted or small rooted teeth are to be moved.

Use of the light round continuous arch wires bent from the hardest wire possible. Not only must the wire have the highest degree of resilience it also must relax under stress. The arch wires also must have the proper form including bite opening bends or curves to control vertical dimension.

Use of molar attachments that prevent free mesio distal tipping and yet permit the arch wires to slide freely. This combination permits the rapid retraction of the anterior teeth as the arch wires slide distally and if desired, facilitates the mesial movement of posterior teeth without pushing the anterior teeth.

Use of auxiliaries on all teeth except the anchor molars.


 Light forces are used, physiologically more acceptable and comfortable.  Efficient anchorage control using intra oral source.  Deep overbites can be opened quickly and effectively.  Quick alignment of teeth can be obtained.  Early resolution of the malocclusion.  Root can be efficiently uprighted and torqued.  Low cost.


 Round wire-ribbon bracket relationship was unable to give the precise control required for a fine finishing.  Posterior root control was very difficult.  Rotational control was poor with the use of undersize wire.  True intrusion of upper incisors was minimal.  Overuse of class II elastics caused: Lack of upper incisors intrusion Undesirable proclination of lower incisors Unfavorable tipping of mand and occlusal plane  Uncontrolled tipping.  Excess uncontrolled tipping in first two stages necessitated a long third stage.


• Changes in the concepts • Improvements in the hardware • Modification in the mechanics

Attritional Occlusion • Corrucini questioned some of the observations in Begg's study. • Many operators have challenged overemphasis on extractions in anticipation of crowding. • Begg's appliance is now totally bifurcated from theory of attritional occlusion

Differential forces • More understanding of biology of tooth movement

Diagnosis •Broad based

Treatment objectives For Static occlusion: Andrews six keys to normal occlusion form the goal. For functional occlusion: Synchronization of CO and CR. Elimination of hanging palatal cusps of upper posterior teeth. Cuspid protected occlusion. Incisor guidance.

Treatment planning Use of orthopedic appliances. Distalization of upper molars. Asymmetric extractions.

Biomechanics Controlled tipping from first stage. Leader in continuing dental education

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