TWEED PHILOSOPHY

PRESENTED BY:

KIRTI AGRAWAL

13-9-2013

HISTORICAL PERSPECTIVE:

Edward Hartley Angle graduated from dental school in 1878.

He developed ANGLE SYSTEM in 1888. According to him , orthodontic appliance

should have 5 objectives: 1) simplicity 2) stability 3) efficiency 4) delicacy 5)inconspicuousness

THE EDGEWISE APPLIANCE:

7TH and final edition of ANGLE’S book was published in 1907 .

He discontinued the use of JACK SCREW.

now, he used ideal heavy expansion arch attached by soldered to molar clasp band.

The heavy arch wire was supplied in 4 different designs.

1) the basic E arch 2) the ribbed E arch 3) the E arch attached to a high pull

head-gear in the incisal area. E arch with hook as seen in the maxilla.

THE E ARCH WITH HIGH PULL HEAD GEAR:

THE PIN AND TUBE APPLIANCE: For bodily movement of teeth ,he developed this

appliance. It was the first appliance with a mechanism for root

movement.

THE RIBBON ARCH APPLIANCE:

Since pin and tube appliance was difficult to use, so he developed this appliance in 1915.

Brackets with vertical slot were introduced with appliance.

It had F control and a degree of stationary anchorage.

The BEGG’s technique is based on this appliance with bracket upside down.

THE EDGEWISE APPLIANCE:

He changed the form of brackets by locating the slot in the center and placing it in the horizontal plane instead of vertical plane.

The new edgewise bracket consist of a rectangular box bracket , .022 inch by .028 inch in dimension.

Its slot open horizontally. Angle introduced the

edgewise bracket in 1928 at the age of 73.

CHARLES H. TWEED

Tweed graduated from a improvised Angle course given by GEORGE HAHN in 1928, he was 33 years old , and ANGLE was 73.

Angle admired TWEED ‘s ability , he asked him to help in article ,published in DENTAL COSMOS.

He returned to Arizona and started 1st edgewise specialty practice in United State.

On august 11, 1930 Angle died at the age of 75.

In 1932 , tweed published 1st article in ANGLE ORTHODONTICS.

The article was “report of cases treated with edgewise arch mechanism”.

TWEED held to ANGLE’S firm conviction that one must never extract the teeth.

But the result was very unsatisfactory . he almost gave up the orthodontic practice.

He observed that 1) in the analysis of non extraction cases, only 20% was successful.

2) upright mandibular incisors are related to post treatment facial balance and harmony.

He concluded that one should prepare the anchorage and extract the teeth where needed.

He retreated his 80% of failure cases with the extraction of 4 first premolar.

In 1936, tweed publish his first paper on EXTRACTION OF TEETH FOR ORTHODONTIC MALOCCLUSION CORRECTION.

MOTHER ANGLE refused to attend the lecture,and GEORGE HANN criticized him severely.

In 1940, tweed present a paper and display his case report in meeting of ANGLE SOCIETY in CHIKAGO.

In this way, tweed philosophy was born. Angle gave orthodontics the edgewise

bracket, but tweed gave the specialty the appliance.

Tweed was considered the premier edgewise orthodontist of those day.

He devoted 42 years of his life in advancement of edgewise appliance and died on 11 January 1970.

ANCHORAGE PREPARATION

First degree •When total discrepancy ≤ 10 m.m.•0< ANB angle< 4

Second degree•When ANB angle> 4.5

Third degree•Total discrepancy = 14-20 m.m.•ANB angle ≤ 5

First degree anchorage preparation is done in high cuspid, crossbite pseudo class , and true class cases.

First degree means mandibular 3rd molar must always be uprighted

In second degree anchorage preparation, When second molar are in full

eruption ,they should always be bonded. The mandibular terminal molar must be

tipped distally so that their distal marginal ridge are at the gum level

In third degree anchorage preparation , jigs are necessary.

All posterior teeth from 2nd premolar must be tipped distally to anchorage preparation in such a way distal marginal ridge of terminal 2nd molar are below to gum level.

FACIA L GROWTH TRENDS

CLASSIFICATION OF FACIAL GROWTH TRENDS:

FACIAL GROWTH TRENDS

Type A25%

Type B15%

Type C60%

Type A :

Middle and lower face grows in forward and downward in unison with no change in size of ANB angle.

Growth is approximately equal in both vertical and horizontal dimension.

SUBDEVISION OF TYPE A

CLASS with ANB angle<4.5

No treatment is indicated untill the full eruption of all 4

cuspid teeth following the serial extraction

TYPE B:

Middle face grows more rapidly than the lower face.

Growth occurs predominantly in the vertical dimension.

Sub division of type B:

When 4>ANB angle

Prognosis is fair.

Type C :

Lower face growing downward and forward more rapidly than the middle face with decrease size of ANB angle.

Growth occurs predominantly in the horizontal direction.

Mandibular incisors cutting

edge engage in the lingual surface of maxillary incisors.

Maxillary incisors are tipped labillary if orbicularis-oris

is is more relaxed.

Lingual tipping of mandibular incisors, as the orbicularis- oris muscle is thin

and strong.

Subdivision of type C:

WHEN GROWTH IS CONFINED TO HORIZONTAL

DIMENTION WITH LITTLE VERTICAL GROWTH.

The diagnostic facial triangle:

The Diagnostic Facial Triangle:

Tweed divided the patient in 2 groups

Patient with balance and harmony of facial proportion

Inclination of mandibular incisor was 90 in relation to body of mandible. H. I. MARGOLIS suggest to check the

inclination of incisors in relation to the mandibular border.

So the conclusion was normal range of mandibular incisors is 90±5 when related to the mandibular plane. In this way , first angle IMPA of diagnostic triangle was established after

12 years of research.

IMPA angle:

In the analysis of non-extraction case , only 20% of patient was successfully treated.

In class II non-extraction cases , maxillary 3rd molars was looking down his throat .so he retreated his patient following the extraction of all 1st premolars .

Result was good, balance and harmony of facial proportion was established.

In 1944 , tweed reviewed the cephalometric literature , and he was impressed by the LATERAL HEAD OF TRACING OF BROADBENT.

Frankfort horizontal plane:

THE FRANKFORT PLANE was established by connecting the point 4.5 mm above the geometrical center of ear rod and the orbitale point midway between left and right border of orbit.

Tweed extended the mandibular border posterior and connect with F.H. PLANE.

He concluded the normal variation of FMA angle was 16-35.

ANB angle is very important it expressed the mesio-distal relationship of maxillary and mandibular basal bone.

Range of ANB is 5 to 12 , and in 65% cases ANB angle is measured 3 to 0.

FMA angle:

ANB angle:

Since sum of all triangle is 180, so the third angle FMIA must be 65.

CONCLUSION

FMA angle >30 the occlusal plane conversed posteriorly,

in relation to mandibular plane

If FMA angle =25± 4 The occlusal plane does not conversed posteriorly

If FMA angle <30 the occlusal plane conversed

posteriorly less,sometimes it is II to it.

TWEED fulfill the ANGLE’S definite of occlusion ,beauty, harmony and balance and establishment of near approach to normal occlusion.