Ch 5 Orthodontics

Orthodontic

assessment

By : Cezar Edward

Introduction to orthodontic

assessment • taking a full history

• undertaking a clinical examination

• collecting appropriate records

Taking an orthodontic history 1-Patient’s perception of the problem

(Patient’s complaint)

2-Medical history

3-Dental historyany trauma, any previous or ongoing dental

treatment, TMJ problems, any known inherited dental problems

(e.g. hypodontia), any previous orthodontic treatment

4-Habits (e.g :digit sucking)

5-Physical growth status(identifying whether growth is

complete or still ongoing may affect the timing and nature of future treatment)

6-Motivation and expectation :if a patient is not

sufficiently motivated, then treatment should not be undertaken.

7-Socio-behavioural factors the patient’s ability to attend

regularly for appointments because it is long term therapy

Extra-oral examination

1-Anteroposterior assessment

2-Vertical assessment

3-Transverse Assessment

4-Smile aesthetics

5-Soft tissue examination

6-Temporomandibular (TMJ) examination

The patient is assessed extra-orally in the:

• frontal view (assessing in the vertical and transverse planes)

• profile view (assessing in the anteroposterior and vertical planes)

1-Anteroposterior assessmentThe anteroposterior relationship can be assessed in three ways:

• assessing the relationship of the lips to a vertical line, known as zero

meridian, dropped from soft tissue nasion

• palpating the anterior portion of the maxilla at A point and the mandible

at B point

• assessing the convexity of the face by determining the angle

between the middle and lower thirds of the face in profile

2-Vertical assessment

The face can be assessed vertically in two ways:

• using the rule of thirds

• measuring the angle of the lower border of the mandible to the maxilla

3-Transverse Assessment

The transverse examination of the face

should be done from the front, and from above the

patient (by standing behind and above the patient).

A patient with marked mandibular

asymmetry to the right.

4-Smile aesthetics• The whole height of the upper incisors should be visible on full smiling,

with only the interproximal gingivae visible. This smile line is usually

1–2 mm higher in females.

• The upper incisor edges should run parallel to the lower lip (smile arc)

• The upper incisors should be close to, but not touching, the lower lip

• The gingival margins of the anterior teeth are important if they are

visible in the smile. The margins of the central incisors and canines

should be approximately level, with the lateral incisors lying 1 mm

more incisally than the canines and central incisors

• The width of the smile should be such that buccal corridors should be

visible, but minimal. The buccal corridor is the space between the angle

of the mouth and the buccal surfaces of the most distal visible tooth.

• There should be a symmetrical dental arrangement

• The upper dental midline should be coincident to the middle of

the face.

5-Soft tissue examination

1-Lips

2-Tongue

Features of the lips to assess

• Lip competence

• Lip fullness

• Nasolabial angle

• Method of achieving an anterior seal

Lips can be competent (that is meet together at rest), potentially

competent (position of incisors prevents comfortable lip seal to be

obtained) or incompetent (require considerable muscular activity

to obtain a lip seal).

In some patients with incompetent lips the tongue

thrusts forward to contact with the lips to form an anterior seal. This

is usually adaptive to the underlying malocclusion, so when the treatment

is complete and normal lip competence can be achieved, the

tongue thrust ceases. In some patients there is a so-called endogenous

tongue thrust, which will re-establish itself after treatment, leading to

relapse.

Lips

Tongue

NasoLabial Angle

90-110 *

6-Temporomandibular (TMJ)

examination

Any tenderness, clicks, crepitus and locking should be noted.

there is no strong evidence to suggest that TMJ disorders are either

associated with malocclusions or cured by orthodontic treatment.

However, if signs or symptoms are detected then they must be

recorded and it may be worth referring the patient to a specialist before

commencing orthodontic treatment.

Intra-oral examination 1-Assessment of oral health

2-Assessment of each dental arch

3-Assessment of arches in occlusion :

Incisor classification

Overjet

Overbite

Centrelines

Canine relationship

Molar relationship

Crossbites

1-Assessment of oral health

Generally any pathology needs to be treated

and stabilised before any orthodontic treatment can be undertaken.

Dental pathology can have a significant influence on the treatment

plan, and additional radiographs and special tests (such as vitality

tests) may be required. We are particularly interested in detecting:

• caries

• areas of hypomineralisation

• effects of previous trauma

• tooth wear

• teeth of abnormal size or shape

• existing restorations which may change the way we bond to the

tooth, as well determine our choice of extractions if space is required

2-Assessment of each dental archEach arch is assessed individually for:

• crowding (see Box 5.4) or spacing

• alignment of teeth, including displacements or rotations of teeth

• inclination of the labial segments (proclined, upright or retroclined)

• angulation of the canines (mesial, upright or distal) as this affects

anchorage assessment later

• arch shape and symmetry

• depth of Curve of Spee

Box 5.4 Describing the amount of

crowding present

0–4 mm = Mild crowding

4–8 mm = Moderate crowding

> 8 mm = Severe crowding

3-Assessment of arches in occlusionThe arches are now assessed in occlusion. The incisor relationships are

assessed first: incisor classifi cation, overjet or anterior crossbites (anteroposterior),

overbite or openbite (vertical) and centrelines (transverse).

Then the buccal relationships are assessed: canine and molar relationships

(anteroposterior), any lateral openbites (vertical) and buccal

crossbites (transverse).

OVERJET :Normally be 2–4 mm

OVERBITE: normal value would be 1/3 coverage of the crown of the lower incisor.

Crossbites • Location (anterior or posterior)

• Nature of the crossbite (see Box 5.5)

Diagnostic records

Purposes:

• Diagnosis and treatment planning

• Monitoring growth

• Monitoring treatment

• Medico-legal record

• Patient communication and education

• Audit and research

1- Study models

Upper =Notch

Lower=Round

Study models should show all the erupted teeth and be extended into

the buccal sulcus. They are poured in dental stone and typically produced

from alginate impressions. They should be mounted in occlusion,

using a wax or polysiloxane bite. They are produced using a

technique known as Angle trimming, which allows models to be placed

on a flat surface and viewed in the correct occlusion from varying angles

2- Photographs

These provide a key colour record. The usual views taken are:

Four extra-oral (in natural head position):

• Full facial frontal at rest

• Full facial frontal smiling

• Facial three-quarters view

• Facial profile

Five intra-oral:

• Frontal occlusion

• Buccal occlusion (left and right)

• Occlusal views of upper and lower arch

3-Radiographs

• Presence or absence of teeth

• Stage of development of adult dentition

• Root morphology of teeth

• Presence of ectopic or supernumerary teeth

• Presence of dental disease

• Relationship of the teeth to the skeletal dental bases, and their

relationship to the cranial base

Types

Cone beam computed tomography

(CBCT) and 3D imaging

CBCT is a faster, more compact version of traditional CT with a lower dose of

radiation.

Through the use of a cone-shaped X-ray beam, the size of the scanner,

radiation dosage and time needed for scanning are all dramatically reduced.

Fig. 5.17 Cone-beam computed tomography

(CBCT) of the patient with the impacted

canine shown in Figs 5.15 and 5.16,

confirming that there is a small amount

of root resorption occuring on the palatal

aspect of the upper left lateral incisor, close

to the apex of the tooth.

Forming a problem list

The information collected from the history,

examination and records, produces a

database identifying a list of problems. It is

this list of problems that allows the clinician

to form a diagnosis

Reference

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