History and Examination, Classification, Terminology and IOTN

What is orthodontics?

• Branch of dentistry concerned with the alignment and development of teeth and jaws

Overview clinical examination

History:

How could family history and past dental history be important?

In extra oral examination what 2 main things are being looked at?

• Skeletal

• Soft tissue

What are 3 skeletal relationships?

• Anteroposterior A-P (maxilla and mandible relative positioning to each other)

• Vertical

• Transverse

What 3 things can be assessed in soft tissue?

• lip competence

• Incisal display

• Lip protrusion

2 Methods of A-P skeletal pattern assessment

• Palpation (bimanual palpation method, do with fingers)

• Zero meridian methods

What are the 3 possible classifications of skeletal pattern?

1 - normal relationship (between maxilla and mandible)

2 - mandible relatively retrusive

3 - mandible relatively protrusive

How to perform the palpation method?

How to perform zero meridian method?

tragus, infraorbital rim - frankfurt plane

zero meridan line is perpendicular through the Frankfurt plane and passes through the nasion

How to measure skeletal classification using the zero meridian method?

Deepest concavity of the lip - reference

Extra-oral examination:

2 measurements for vertical skeletal relations

• Angular measurement

• Linear measurement

What is angular measurement

2 planes and reference point

• Frankfurt plane intersecting with mandibular plane - reference at the occiput - average both lines meet at the occiput in averagely proportioned individual

Linear measurements? (2 methods?)

• Proportions - mid-eyebrows to base of nose should equal base of nose to base of chin

• Absolute measurement

What is the Frankfurt Manidbular planes angle?

Again what are the references in vertical measurement?

• lower anterioir face and midface

• lower anterioir face height - soft tissue menton up to subnasale

• midface height - glabella to subnasale

should be equal

What is the lower anterioir face heights?

what is absolute measurements based on?

lower anterioir face height (FMPA) with those with high angle

reduced lower anterior face height also usually associated with low angle

Based on Caucasian - 16 yo, males is 72 mm and 66 mm for females

Transverse skeletal relations

How can it be assessed?

• Asses for facial symmetry - front above and behind (birds viewpoint)

• mid eyebrow, tip of nose, philtrum chin should all line up (some people can have crooked nose, most people have a degree of asymmetry)

• in occlusion and teeth apart (if there is a difference in the asymmetry of the mandible on closure)

Extra oral assessment: soft tissues

what are the 3 main structures?

lips

tongue

cheeks

What are 3 things to comment about lips?

• Morphology

• Competence at rest (should meet at rest or need strain to meet at rest then incompetent)

• (lower lip should cover the incisal third of the upper incisors - get pt at rest and lift upper lip slightly up)

• Function - not excessive contracture of muscles when lips are together - have a feel how tense the muscle are

lip morphology?

What is the definition of competent lips?

• Lips held together at rest

• Minimal detectable electrical activity in circumoral musculature

Definition of incompetent lips?

(tend to breath through mouth)

• Lips are apart at rest

• some lips are held together by circumoral and mentalis contraction - check chin

What skeletal features are commonly associated with lip incompetence?

Skeletal 2 - mandible is behind maxilla so pt finds it difficult to close lips

increase LAFH - vertical distance is large so difficult to hold lips together - incisors are also in the way , the picture shows the activation of the chin muscles

What is soft tissue protrusion

what is the line called?

How much do lips protrude in relation to Rickett’s E-line (Esthetic)

far behind - retrusive

In front - protrusive

What is this showing?

• At rest peel the lower lip back - 3-4 mm for males and 4-5 mm for females

• Majority of crown and up to 2mm of gingiva - when smiling is normal

Incisal display

Tongue assessment?

at rest and function

• Rest: size of the tongue in relation to oral cavity, resting posture

• Function: adaptive tongue swallow pattern, endogenous tongue swallow - neuromuscular/down syndrome

Intraoral examination

2 main categories?

Intra-arch oral features - teeth at each arch individually

Inter-arch

What are 3 things to look for in intra-arch assessment?

• Alignment of teeth - rotations

• Spaced or crowded - graded

• Inclination - normal, retroclined and proclined

mesio-Labial and disto-palatal rotations is the same thing so pick one

Crowding classification

How much space is missing for all teeth to be aligned within the length of the arch

“ There would need to be 8 more mm in the arch for all the teeth to be comfortably aligned”

Spacing - how is it categorised

• generalised or localised

• Maxillary median diastema

1st picture - localised in the upper anterior segment

2nd picture median diastema in the maxillary and mandibular arch

Angulation of teeth - mesiodistal tip - intra arch assessment

mesio-distal relationship between crown and the root

most teeth - crown is little more mesial to the root - particularly anterioir teeth

Inclination: bucco-lingual orientation

crown and root position relationship

applies mainly to anterioir teeth

crown is slightly more labial than root in anterioir teeth

posterior segment - root is not more buccal than crown - root is not more buccal than crown

incisor inclination avg degrees

retroclined if crown is further forwards than expected

proclined with an overjet

Interarch

occlusal traits

Incisal relationship is between what

Relationship of lower incisors to palatal aspect of upper incisors

What are the 3 incisor relationships?

overjet is normal in div 2 but teeth are retroclined which explains why the overjet is not increased and could even be reduced

div 1 - class 2 with normal inclination leads to inc overjet and made worse with proclination

class 3 - can meet at the lower incisal third or anterioir

What relationship is this?

Can use a mirror under the incisal edge to see this

What incisor relationship is this?

about 12mm overjet

What incisor relationship is this?

features tend not to show overjet such as in div 1

Relationship?

not necessary to have a reverse bite for class 3

What is overjet and overbite?

• After classification

• overjet - AP measurement distance between labial surface of lower incisors and incisal edge of upper incisors

• Overbite - overlap between upper and lower incisors

How can overjet be described as?

• Increased, normal, reduced or a reversed overjet

• Ideally 2-4 mm

Overbite ideal measurement?

1/3 up to ½ of lower incisor covered by upper incisor?

Classifications of overbites?

• normal, reduced, increased, anterior open bite (when you look in front)

• complete (teeth in contact with something/teeth/gingiva/palate) or incomplete (no contact)

Describe this in terms of the level and if complete or incomplete?

complete (to palatal mucosa) increased overbite - traumatic as there is indentation of the mower incisors on the palate

What are centrelines?

4 points

Could be dental reasons or skeletal asymmetry

What is a molar class 1 relationship

Mainly based on the 6, if not present then use other teeth

What is a class 2 and 3 molar relationship?

full unit 2 relationship - the distobuccal cusp occludes where the mesial buccal cusp should occlude

Molar relationship using canines?

in a class 1,2 1 unit, 2 ½ unit, 3 ½ unit

Crossbites:

Upper teeth should occlude x to lower teeth

what are the categories of crossbites?

• buccal

• anterioir or posteiror

• unilateral or bilateral

Once you decide there is a crossbite, what must you then decide

Displacement?

Shift between Retruded contact and ICP

Aetiology of malocclusion? (4)

• Genetic control - skeletal relations

• Environmental factors - soft tissues and habits

• Dento-alveolar local factors

TX aims

facial (1)

dental (5)

• Facial: accept or address skeletal pattern

• Dental:

• relieve dental crowding and align teeth

• reduce overbite and overjet (if incorrect)

• eliminate cross-bite and associated mandibular displacement

• achieve class 2 incisor and molar relationship

• Retention at the end

How to present patients

Ideal static occlusion?

(4) andrews

Andrews ideal occlusion

what are the 6 keys?

• molar relationship

• correct angulation

• correct inclination

• no rotations

• no spacing

• flat curve of spree

IOTN - index of orthodontic treatment needs

2 aspects of the IOTN

grades 1-5 for the dental health component

1-10 for aesthetics

give a score for each

MOCDO - dental health component

displacement of contact points - measure of most displaced contact points - crowding

IOTN scores and meaning?