Orthodontic Assessment Flashcards
What is the purpose of an orthodontic assessment?
To determine if there is any malocclusion present
When should an ortho assessment typically be done?
First BRIEF exam at age 9
Comprehensive exam when premolars and canines erupt at 11/12
What are the 6 keys of Andrews (ideal occlusion)?
- Molar relationship class I
- Crown angulation
- Crown inclincation
- No rotations
- No spaces
- Flat occlusal planes (no curve of spee)
What are the occlusal features caused by digit sucking?
Proclination of the upper anteriors
Retroclined lower anteriors
Localised AOB or incomplete open bite
Narrow upper arch +/- unilateral crossbite
What are some ways a digit sucking habit can be prevented or stopped?
URA
Behavioural management therapy (positive re-enforcement for example)
Sock on hands at night
Plasters on fingers/ thumbs
Bad tastes
What is a unilateral posterior crossbite and what is a common cause?
When at ICP the mandibular teeth of only one side are located buccally to the maxillary teeth
Caused by narrowness of both sides of the upper arch
What are some habits that can cause a malocclusion?
Digit sucking
Lower lip sucking
Tongue thrust - creates AOB
Biting fingernails
How do you clinically assess the AP (antero-posterior) skeletal class?
Visual assessment - assess where point A and B are (A - philtrum of lip, B - Chin)
Palpate skeletal bases
What is the BSI class I incisor relationship?
The lower incisal edges occlude with or lie immediately below the cingulum of the upper incisors
How is an AOB created with a digit sucking habit?
The sucking action initiated by the muscular forces in the cheeks narrows the maxillary arch, causing a unilateral crossbite
The upper teeth procline and the lower teeth retrocline in response, so as to “make space” for the digit.
What is a class I sk relationship?
Normal
maxilla 2-3mm in front of mandible
What is class II sk relationship?
Maxilla more than 3 mm in front of mandible
What is a class III sk relationship?
Mandible in front of maxilla
What is the frankfort horizontal plane?
Between external auditory meatus and the ala of the nose.
What are the steps of an extra-oral orthodontic assessment?
Patient details
C/O, PMH, PDH
Skeletal base - AP, vertical, transverse
LAFH
Lip trap
Nasiolabial
Smile line
What is BSI class II div I incisor relationship?
The lower incisal edge occludes behind the cingulum of the upper central incisors and the upper incisors are proclined. Increased overjet.
What is BSI class II div II incisor relationship?
The lower incisal edge occludes behind the cingulum of the upper central incisors, and the upper incisors are retroclined (the lateral incisors may be proclined). Overjet is usually minimal or may be increased.
What is the BSI incisor relationship for class III?
Class III - lower incisal edge occludes in front of the cingulum of the upper incisors
What medical history would contra-indicate ortho treatment?
Allergy to nickel or latex - nickel allergy only a problem if they cannot hold keys/ coins
If patient has a medical condition that requires them to have regular MRI scans
What may increased FMPA indicate?
Class III sk base
What may decreased FMPA indicate?C
Class II sk base
What is Molar relationship class I?
mesio-buccal cusp of upper 6 in buccal groove of lower 6
What is molar full unit class II?
mesio-buccal cusp of upper 6 sits in front of mesio-buccal cusp of lower 6
What is molar class III relationship?
mesio-buccal cusp of upper 6 occludes against disto-buccal cusp of lower 6
