ORTHODONTICS

Treatment planning

By Cezar Edward

When planning orthodontic treatment the following

areas need to be considered:

• Aesthetics

• Oral health

• Function

• Stability

In order to make this problem list more understandable, it can be classified into six sections:

(1) The patient’s concerns

(2) Facial and smile aesthetics

(3) Alignment and symmetry within each arch

(4) Skeletal and dental relationships in the transverse plane

(5) Skeletal and dental relationships in the anteroposterior plane

(6) Skeletal and dental relationships in the vertical plane

(1) The patient’s concerns

The patient’s role in orthodontic treatment success is

vital. The following areas need to be considered:

• Patient’s concerns

• Patient’s expectations

• Patient motivation

If the patient’s expectations are unrealistic, then

treatment should not be undertaken.

(2) Facial and smile aesthetics

The area of facial aesthetics is affected by personal

and cultural factors and also by fashions and trends.

We need to make a good assessment

Labial and buccal fullness …

Black line :before

Blue Line :After

(3) Alignment and symmetry

within each arch

The amount of crowding or spacing in each arch needs

to be assessed, as well as the inclination of the upper and

lower incisors and any tooth size discrepancies identified.

This will play a major role in assessing the amount of

space required to treat the case. The process of

determining the amount of space required is called

‘space analysis’

(4,5,6) Skeletal and dental

relationships in all three dimensions

The aim is to describe the occlusion, distinguishing

between the dental and skeletal

factors contributing to the malocclusion in each plane.

Generally, it is easier to correct malocclusions that are

due to dental problems alone

– if there are underlying skeletal problems, these are often

more difficult to treat.

Skeletal problems and treatment

planning

There are three options for treating malocclusions with

underlying skeletal problems:

1• Orthodontic camouflage”المظهر الزائف ”

2• Growth modification

3• Combined orthodontic and surgical approach

1• Orthodontic camouflage

Treatment with orthodontic camouflage means that the

skeletal discrepancy is accepted, but the teeth are

moved into a Class I relationship.

The smaller the skeletal contribution to the malocclusion,

the more likely that orthodontic camouflage will be

possible. It is easier to camouflage anteroposterior

skeletal problems than vertical problems, which in turn

are easier to camouflage than transverse problems.

2• Growth modificationThis type of treatment is also known as dentofacial

orthopaedics and is only possible in growing patients. By

use of orthodontic appliances,

minor changes can be made to the skeletal pattern.

Most growth modification is used to correct

anteroposterior discrepancies as it is harder to

make changes in the vertical dimension and even more

difficult to alter transverse skeletal discrepancies.

Headgear

functional appliances

Basic principles in orthodontic

treatment planning

1 Oral health :The first part of any orthodontic

treatment plan is to establish and maintain good oral

health during the treatment.

2 The lower arch :very important because the lower

labial segment is positioned in an area of relative

stability between the tongue lingually, and the lips and

cheeks labially and buccally. Any excessive movement

of the lower labial segment would increase the risk of

relapse.

examples of when the lower incisors may be proclined:-

• Cases presenting with very mild lower incisor crowding

• Treatment of deep overbites, particularly in Class II

division 2

• Patients who had a digit-sucking habit (where the

lower incisors have been held back from their natural

position by the habit)

• To prevent unfavourable profi le changes in reduction

of large overjets

when surgery is not indicated or declined

3 The upper arch

Once the lower arch has been planned, the upper

arch position can be planned in order to obtain a

Class I incisor relationship. The secret to achieving a

Class I incisor relationship is to get the canines into a

Class I relationship.

It is helpful to anticipate the position of the lower

canine once the lower labial segment has been aligned and

positioned appropriately. It is then possible to mentally reposition

the maxillary canine so that it is in a Class I relationship with the

lower canine.

This gives the clinician an idea of how much space will be

required and how far the upper canine will need to be moved. This

will also give an indication of the type of movement and therefore

type of appliance required, as well as providing information about

anchorage requirements.

4 Buccal segments

Although the aim is usually to obtain a Class I canine

relationship, it is not necessary to always have a Class I

molar relationship.

Typically, more extractions are needed in the upper arch

in Class II cases, to allow retraction of the upper labial

segment to camouflage the underlying

skeletal pattern. However, in Class III cases treated

orthodontically extractions are more likely in the lower

arch to allow retroclination of the lower labial segment.

5 Anchorage

Anchorage planning is about resisting unwanted tooth

movement.

It is vital that anchorage is understood and planned

correctly for a treatment plan to work.

6 Treatment mechanicsthe choice of treatment mechanics is often determined by the clinician’s

expertise and experience with different techniques. The clinician should

utilize mechanics that produce the desired result in the most efficient and

predictable way, while avoiding any risks or undesirable side-effects

and minimizing the compliance required from the patient.

It is important to mention that the aims of the treatment should be determined

first, and then the appropriate appliances and treatment mechanics

chosen to deliver these aims. The appliance system and the treatment

mechanics should not be used to determine the treatment aims.

7 Retention =No Relapse !

Wearing retainers requires commitment from the

patient and they should be made aware of the need

for these retainers before treatment begins

Space analysis is a process that allows an estimation of the

space required in each arch to fulfil the treatment aims.

Although not an exact science, it does allow a disciplined

approach to diagnosis and treatment

planning. It also helps to determine whether the treatment

aims are feasible, as well as assisting with the planning of

treatment mechanics and anchorage control.

Space analysis

Space planning is carried out in two phases: the first is to determine

the space required and the second calculates the amount of space that

will be created during treatment. This includes creating space for any

planned prostheses.

1-Calculating the space

requirements

1• Crowding

2• Incisor anteroposterior change (usually obtaining a

normal overjet of 2 mm)

The amount of crowding present is often

classified as:

• Mild (<4 mm)

• Moderate (4–8 mm)

• Severe (>8 mm)

If incisors are retracted, this requires space; if incisors are proclined

then space is created.

The aim is to create an overjet of 2 mm at the end of treatment. Every

millimetre of incisor retraction requires 2 mm of space in the dental

arch. Conversely, for every millimetre of incisor proclination 2 mm of

space are created in the arch.

Space is required to correct the following:

3-Levelling occlusal curves: Where there is no occlusal

stop the lower incisors may over-erupt. This

may result in an occlusal curve which runs from the

molars to the incisors and is known as a Curve of Spee

The amount of space required to level an increased

curve of Spee is controversial, as it is affected by a

number of factors, such as the shape of the archform

and tooth shape.

•4- Arch contraction (expansion will create space)

•5- Correction of upper incisor angulation (mesiodistal tip)

•6- Correction of upper incisor inclination (torque)

2-Creating space

Space can be created by one or more of the

following:

• Extractions : Often Premolars

• Distal movement of molars

• Enamel stripping

• Expansion

• Proclination of incisors

• A combination of any or all of the above

2-Distal movement of molarsDistal movement of molars in the upper arch is possible.

This movement can be achieved with headgear. Extra-

oral traction using headgear

will usually produce up to 2–3 mm per side (creating 4–6

mm space in total). It therefore tends to be used when

there is a mild space requirement where extractions may

produce too much space. It can also be used in addition

to extractions when there is a very high space

requirement.

Temporary bone anchorage devices (TADS) offer an alternative

to headgear in some cases. Appliances attached to these

anchorage devices can be used to distalize upper molars.

Distal movement of the lower first molar is very difficult and in

reality the best that can be achieved is uprighting of this tooth.

3-Enamel strippingEnamel interproximal reduction or ’stripping‘ is the removal of a

small amount of enamel on the mesial and distal aspect of teeth and

is sometimes known as reproximation. In addition to creating space,

the process has been advocated for improving the shape and contact

points of teeth, and possibly enhancing stability at the end of

treatment.

On the anterior teeth approximately 0.5 mm can be removed on each

tooth (0.25 mm mesial and distal) without compromising the

health of the teeth. Enamel can be carefully removed with an abrasive

Strip The abrasive strip can be used in conjunction with

pumice mixed with acid etch, to provide a smoother surface finish.

The teeth are treated topically with fluoride following reduction of

the enamel.

4-Expansion

Space can be created by expanding the upper arch laterally –

approximately 0.5 mm is created for every 1 mm of posterior arch

expansion. Expansion should ideally only be undertaken when

there is a crossbite.

Space can be created by proclining incisors, but this will be

dictated by the aims of the treatment. Each millimetre of

incisor advancement creates approximately 2 mm of space

within the dental arch.

5-Proclination of incisors

Informed consent and the

orthodontic treatment planInformed consent means the patient is given information to help

them to understand the:

• malocclusion

• proposed treatment and alternatives

• commitment required

• duration of treatment

• cost implications

Treatment alternatives, which must always include no treatment as

an option, must be clearly explained, with the risks and benefits of

each approach carefully discussed.

If a competent child consents to treatment, a parent

cannot override this decision – this is known as ‘Gillick competence’.

Reference