Bracket Placement .Prof. Maher Fouda

Placement of

orthodontic brackets

Prof. Dr. Maher Abdelsalam Fouda

Orthodontic DepartmentFaculty of Dentistry - Mansoura University

A Proper Finish Begins With a Proper Start

Perhaps the single-most-important phase of orthodontic treatment is

proper bracket placement.

Taking time to achieve proper placement at the outset can help

mitigate—or even eliminate—final archwire bends and correction.

Facial Axis of the Clinical Crown (FACC).The most prominent portion of the central

lobe on each crown’s facial surface. For molars, the buccal groove that separates the

two facial cusps.

Facial Axis Point (FA point): The point on the facial axis that separates the gingival half of the

clinical crown from the occlusal half.

Andrews® Plane: The surface or plane on which the mid-transverse plane of every crown in an

arch will fall when the teeth are optimally positioned. This plane virtually connects the

appliance through the FA point.

Upper Arch FA Point & FACC

Upper Arch Brackets On Andrews® Plane Line

Lower Arch FA Point & FACC

Lower Arch Brackets On Andrews® Plane Line

The accurately placed brackets will give better control on

three dimension position of the teeth during treatment.

An accurately placed bracket will also result in better

expression of its built in prescription and orthodontist will

need less wire bending and complex mechanics during

the course of treatment.

Mesiodistal position of brackets

It is a general saying in orthodontics that brackets

should be placed at mesiodistal center of the teeth.

This statement is partially correct as this rule can't be

applied to all the teeth.

A more clear description for right mesiodistal

position of brackets was given by Andrew that

brackets should ideally be placed at the mid

developmental ridge of the teeth.

Maxillary and mandibular incisors

Bracket should ideally be placed at mesiodistal center of

maxillary and mandibular incisors. The mid developmental

ridge of these teeth is also present at their mesiodistal

center of the labial surface

.

Maxillary and mandibular incisors

Vertical lines showing mesiodistal center of the

upper and lower incisors. Brackets should be

placed at the recommended height on this line.

Maxillary and mandibular Canines

Placing brackets at the mesiodistal center of the canines will result in contact

point error and slight rotation of the teeth as the mid developmental ridge of

upper and lower canines lies slightly mesial to the mesiodistal center of

the teeth and is more mesial in case of lower canines. So bracket is placed

slightly off center and toward mesial, in case of canines.

Bracket is placed slightly off center and toward

mesial, in case of canines

{

The vertical lines on maxillary and mandibular canines indicate the

mid developmental ridge of the canines and ideally the middle of

the brackets should coincide with this line.

Mandibular Premolars

Roth purposed that premolars brackets should

be placed at area of maximum convexity which is

usually the mesiodistal center of the teeth and

mid developmental ridge also lies in this area.


Sometimes the area of maximum convexity lies slightly

mesial to the mesiodistal center but degree of mesial

deviation is less than that of canines. The difference between

bracket placement on premolars and anterior teeth is

presence of a lingual cusp on premolars which must be taken

into consideration while placing

the brackets.

M D


Maximum convexity lies slightly mesial to the

mesiodistal center. The cast of the patient should

be examined to detect position of the maximum convexity



In mandibular premolars the buccal and lingual

cusps lies at the same level in the mesiodistal

perspective. So when placing

lower premolar brackets the scribe line of the

bracket should coincide with line connecting the

buccal and lingual cusps


A left lower 2nd premolar bracket bonded so that the

line connecting the buccal and lingual cusps passes

through the scribe line of the bracket. This is because

buccal and lingual cusps of the lower premolars should

be present at the same level in mesiodistal perspective.


In maxillary premolars, brackets should be placed so that

the scribe line of the bracket is slightly mesial of up to 0.5

mm to the line connecting the buccal and lingual cusps

Maxillary Premolars

Bracket placement on maxillary premolars is different from mandibular

premolars as maxillary premolars should have slightly rotated position at

the end the treatment while the lingual cusps have cusp fossa

relationship with lower premolars in class I & II molar occlusion

Maxillary Premolars

Maxillary premolars should have

slightly rotated position at the end the treatment.

According to Andrew six keys of normal

occlusion the buccal cusps of upper premolars

should have a cusp embrasure relationship with lower premolars

According to Andrew six keys of normal

occlusion the buccal cusps of upper

premolars should have a cusp embrasure relationship with lower premolars

So if the buccal and lingual cusps are in one line

in the mesiodistal perspective then both buccal

and lingual cusps will have a cusp embrasure

relationship with lower dentition. Such a relation is

not acceptable .

According to Andrew1 the buccal

cusps of upper premolars should

be slightly more distal than the

lingual cusps in the mesiodistal

perspective

So in maxillary premolars, brackets should be placed so that

the scribe line of the bracket is slightly mesial of up to 0.5

mm to the line connecting the buccal and lingual cusps

A. Keeping the buccal and lingual cusps of maxillary premolars in

the same mesiodistal perspective will cause poor occlusal results..

D. A bracket bonded slightly mesial to line connecting the buccal

and lingual cusp of maxillary 2nd premolar. Bonding the bracket in

this position will rotate the buccal cuspsdistally and lingual cusp

slightly mesial to get ideal relationship in a class I molar relationship

B&C. When the buccal cusp tips of the

maxillary premolars are in line with lower

embrasures their lingual cusps lies slightly

mesial to embrasures and rest at their

corresponding teeth fossas

According to McNamara such a position will also

help to improve class I & II dental relationships

E &F Like class I in class II molar finished cases maxillary

premolar buccal cusp is slightly distal to lingual cusp in

mesiodistal perspective to give ideal occlusal

relationships

For class III molar finished cases though there are

no guidelines available in the literature but the

author opinion is that upper premolars should be

bonded like class I cases in surgical and

orthopedic treatment..

But if the orthodontist is aiming class III

camouflage then upper premolar brackets should

be bonded slightly distal to mid developmental

ridge so that the buccal and lingual cusps have the

same prominence in mesiodistal perspective

{

Maxillary and mandibular molars

Conventionally bands are placed on the molars. The most

suitable band is one that snugly fits the tooth. Whether

molar bands or tubes are used, the optimum mesiodistal

position is decided by taking the mesiobuccal cusp as

reference.

{

The mesial opening of the

tube should lie below the

mesiobuccal cusp at the

correct vertical height

Bands placed on upper and lower molars. The

mesial opening of the tube lies below the mesiobuccal

cusp of the molars. The rule hold true for both 1st and

2nd molars in both arches

Checking mesiodistal position of the brackets

The mesiodistal position of the bracket can be checked under

both direct and indirect vision. For indirect vision diagnostic

mirror is used . Generally mesiodistal position of upper

incisors, premolars and molars brackets is

checked under indirect vision

Modifications in mesiodistal position of the bracket

Alteration in mesiodistal position of the bracket will alter the

prescription of the bracket in terms of counter rotation.

Some situations where mesiodistal position of the bracket is

altered are given.

Rotated teeth

In case of rotated teeth the bracket should always be placed

more on side of rotation in the mesiodistal plane . This

overcorrected position of the bracket will result in early

correction of the rotation and will also accommodate the

relapse factor after debonding.

A rotated maxillary 2nd premolar.

As the tooth is distopalatally

rotated so the bracket is placed

slightly more distal than its

required position

Clinical Notes

Sometimes due to severe rotation or

crowding the position of the tooth is such

that it's not possible to place bracket at the

right mesiodistal center of the tooth

Rotated right upper central incisor.

Correct mesiodistal position of the bracket is not possible on

the first bonding visit due to rotation. The bracket should be

placed as far mesial as possible. The mesial side of the

bracket should not come in contact with left side incisor

because it will hinder the full insertion of the wire and also

make ligature placement extremely difficult if not

impossible

In such situations the bracket should be placed as far as

possible toward the mesiodistal center of the tooth or toward the

rotation. A flexible wire is passed and only the brackets wings

toward the rotation are ligated. At subsequent visit the tooth is

usually derotated enough to place bracket at the right

mesiodistal position

So the bracket is debonded and

either a recycled or new bracket is

rebonded at the correct mesiodistal

position

Clinical Notes

Sometimes the tooth is rotated 180° so that the lingual side is

on the labial side. Many times this form of rotation is

accepted. In such situation the bracket is bonded on the side

of the tooth which is facing labial or buccal .

Right lower lateral is rotated

180°.The rotation was

accepted and bracket placed

on lingual side of the tooth

which was facing labially

Clinical Notes

Another situation is maxillary lateral incisor substitution by canine. In

this situation the slightly convex labial surface

of canine is made flat to give it shape of lateral incisor and bracket is

bonded at mesiodistal center of reshaped canine

instead of slightly mesial.

Placing the bracket at the mid developmental ridge area

will cause poor contact point with the central incisor as canine is

also reshaped mesiodistally. On premolar tooth which

will become future canine the canine bracket is placed distal to

the mesiodistal center of the tooth.

• It is necessary to position these brackets

gingivally to permit the re-contouring of the

canines required for esthetics and function.

• The orthodontist should place the brackets

according to gingival margin height rather

than incisal edge or cusp tip.

Placing the bracket distally will rotate the tooth

mesiopalatally which increases the mesiodistal width of

future canine tooth, bringing the convex part of the tooth

mesial so that it look similar to the mid developmental

ridge of canine

This position of bracket also helps to hide the palatal cusp of

premolar and improves the occlusal relation with the

mandibular canine. The palatal cusp needs to be grounded to

avoid premature contact with opposing dentition.

Axial or long axis position of the brackets

Axial or long axis position of the bracket is related to the angulation or

tip of the teeth. In conventional edgewise system where there was no

built in tip, the brackets were placed angulated on the tooth. The amount

of bracket angulation on the tooth was equal to the amount of tip

required

Standard edgewise brackets has no built in tip. Bracket

position didn't follow long axis of the crown or root and

were placed angular on the tooth equal to the amount of

tip required.

In pre adjusted edgewise system as the tip is already built

within the brackets so placing the bracket similar to standard

edgewise will result in increase or decrease of built in tip. In

pre adjusted edgewise system brackets are positioned on the

tooth so that their wings and scribe line are parallel to long axis

of clinical crowns or long axis of the tooth .

A pre adjusted bracket of maxillary left lateral incisor .Placing

the bracket parallel to long axis of clinical crown will cause tooth

to rotate in a clockwise direction and express the built in tip.

But there is always some difference between the angulation

of long axis of the crown and long axis of the tooth in the

mesiodistal plane .

There is always some

difference between long

axis of clinical crown and

long axis of the tooth

Also placing bracket according to longaxis of tooth may result in wrong

mesiodistal position of bracket on the crown.

Andrew purposed that as the clinical crown is only visible in

the mouth so the angulation of the tooth should be taken by

taking the angulation of long axis of clinical crown (LACC)

and not the long axis of the entire tooth. But taking only

the long axis of clinical crown may result in poor root

parallelism and in some cases root resorption due to roots

approximation of adjacent tooth

A lateral incisor bracket placed with reference to long axis of

clinical crown. X ray showing that long axis of bracket not

coinciding with long axis of the root

and because of this root of the lateral incisor is in close

contact with central incisor root increasing chances of root

resorption in this area.

So brackets should ideally be placed by taking the clinical

crown as reference but root position should also be kept in

mind. If there are chances of adjacent root resorption by

taking clinical crown as reference then bracket position

should be modified and long axis of the tooth should betaken

as reference.

Taking the long axis of tooth can results in poor

proportions of connectors and embrasures . These

proportions can be corrected at end of treatment

either by composite build up or interproximal

reduction.

A. Golden proportion of connectors that ideally should be

present in finished cases. B. A case with dilacerated central

incisor root. If there is root dilacerations, placing bracket by

following the clinical crown will result in ideal connector

areas but greater chances of root approximation and so root

resorption.

C. Bracket placed by following the long axis of the

roots. The golden proportion of connectors is

distorted. They can be resorted by composite built

up or interproximal stripping at the end of

treatment

Clinical notes

Some clinicians also take incisor edge as

guideline for long axis positioning of brackets. But

incisor edge is mostly uneven due to trauma,

attrition and mamelons. So incisor edge shouldn't

be taken as a reference point for long axis

position of the bracket.

Also gingival zenith(top) shouldn't be taken

as a reference for long axis position of the

bracket as it can be effected by uneven

pattern of gingival recession

A. Mamelons on central incisors. These mamelons will give a

different long axis position of the tooth if taken as reference for

bracket positioning. B. Attrition of the incisor edge will also effect

long axis position of the teeth. C. Gingival zenith shifted mesial

from their ideal position due to gingival recession. Taking gingival

zenith as reference for axial position of the

bracket in these cases will result in wrong placement of the

brackets

Importance of axial position of brackets

Correct axial position of the bracket is very important for

proper occlusal and esthetic relationship. As preadjusted

brackets have built in tip, a poor axial position of the

bracket will result in expression of increase or decrease

positive or negative tip. Increase in tip may increase space

requirement in the arch and also increase risk of adjacent

root approximation

A&B. Preadjusted brackets not placed in accordance with long axis of

the tooth will result in increase or decrease expression of tip than the

built in tip. C.A x ray showing that both decreased and increased tip of

incisors due to angular bracket placement. This increases chances of

root approximation and root resorption.

D&E. Over angulated brackets placed on

central incisors can result poor proportion of

connectors and embrasures leading to

development of black triangles

Change in tooth angulation will also affect the golden

proportions of connectors and embrasures and so the smile

esthetics of the teeth.

Checking axial position of brackets

The axial position of the brackets is checked under both

direct and indirect vision. Usually maxillary anterior

brackets and mandibular brackets are checked under direct

vision from labial side of the tooth while maxillary posterior

brackets are checked under indirect vision using diagnostic

mouth mirrors.

If there is doubt in position of maxillary anterior brackets

especially lateral incisor brackets some clinicians favor

to use indirect vision by diagnostic mirror and use

guidance from lingual side of tooth.

Modifications in axial position of brackets

Modifications are made in axial position in the

following circumstances

1. To avoid chances of root resorption due to

adjacent root approximation.

2. To avoid root resorption from dental or

orthodontic implants.

3. To avoid root resorption from teeth

impacted in the bones. i-e impacted

canines or mesiodens ..)

Orthodontic implants inserted for intrusion of maxillary

incisor. Note the position of lateral incisors at both ends.

The gingival wings of the brackets are facing distal so they

will rotate both lateral incisor roots toward mesial. Initially

such bracket placement will create space for implant

insertion and during intrusion it will ensure that roots of

lateral remain away from implants.

Once the intrusion is completed and the implants

are removed, bracket position is corrected so that

lateral incisor have optimum angulation

A mesiodens present between roots of the upper central

incisors. Brackets are placed so that wings of the brackets

are facing mesial on gingival side. This will rotate both the

central incisors roots away from mesiodens and will give

good access to surgeons for removing it without causing

any damage to central incisor roots.

The bracket position needs to be corrected

after mesiodens removal otherwise black

triangle will result in central incisors.

5. In some surgical cases bracket position is modified to

move roots away from surgical site (Wassmound procedure

in maxilla, Subapical osteotomy).

4. To accommodate crown morphology for achieving

golden proportions of connectors and embrasures

6. If teeth have slightly smaller size

such as peg laterals than it is better to

increase the angulation of the teeth

rather then to go for composite build

ups

Health & Medicine

Bracket Placement .Prof. Maher Fouda