Intro to orthodontics Flashcards
Types of appliances
Fixed appliances
Removable appliances
Functional appliances
Malocclusion
Variation from ideal occlusion which has dental health and/ or psychosocial implications for the individual
It is a VARIATION not a disease
Orthodontics
‘straight’ ‘tooth’
Branch of dentistry concerned with growth of teeth, jaws and face
Moves teeth to improve occlusion and appearance, thus correcting malocclusion
Nams button
Bands around 6s, button to stop 6s moving forwards
Functional appliances
Dento-facial orthopaedics - modify growth to improve relationships between facial bones
Used exclusively for Class II patients
Can be used in conjunction with fixed appliances
Removable appliances
Interceptive orthodontics
Little retainer type brace which can do small changes to dentition
Used especially for single tooth movements
When they have not got all teeth through
Benefits
Dental health -caries (e.g. due to crowding) -perio -trauma (e.g. due to increased overjet) -masticatory function -speech -unerupted/ ectopic teeth Psychosocial/ well-being -removes social handicap (positive social status for straight white teeth, negative social judgement of opposite) -negative judgements of others e.g. teasing and bullying (but psychological distress no proportion to malocclusion)
Quadhelix
For posterior crossbite
Overjet
Increase in horizontal distance between upper and lower teeth
Incompetent lips can cause inflamed gingiva
Self-conscious about teeth so don’t clean them
Increased prevalance of trauma with increased OJ
14% with OJ 0-3mm
39% with OJ >6mm
70% of boys affected by age 10
Functinal appliance/ headgear indications
Two phase treatment - age 8-10 and again in adolescence
-for overjet
-less patients suffered incisal trauma
Or observe: one phase treatment - in adolescence
-potentially more economical to restore the trauma
TMJD
The correlations that have been reported between TMD and various malocclusion types are low and unlikely to be of direct clinical significance
Masticatory function/ speech
Often don’t report because never known any different - with eating
No definitive proof that alteration of tooth position can improve articulation disorders
Unerupted/ ectopic teeth
Resorption of surrounding roots
-up to 50% of cases with ectopic maxillary canines demonstrated root resorption
-3x more common in girls than boys
-only 50% of root resorptions seen on an OPT, so we do CBCTs instead
Cystic change (rare)
Risks with treatment
Cost/ inconvenience Pain and discomfort Incomplete treatment Medical disroders -bleeding disorders -epilepsy -allergies OH/ Gingival/ Perio health Demineralisation/ caries Root resorption Relapse
Pain and discomfort
Pain 6 huors after first fitting fixed appliance
Lasts 2-4 days after every adjustment
Incomplete treatment
If they cannot look after their teeth
Root resorption
Mean resorption for all maxillary incisors 0.9m
17% had root shortenings >2.5mm after treatment **
Lots of possible causes, hard to say who it will happen to
IOTN
Index of Orthodontic Treatment Need 2 part index to measure ortho treatment priority -dental health component (DHC) -aesthetic component (AC) To assess if qualify for NHS
DHC
5 grades - 4 and 5 qualify for treatment on the NHS
AC
10 photos
Compare with models (or patient)
Grades 1-10
Not used as much now
Occlusal indices
Index of Ortho Treatment Need (IOTN)
Peer Assessment Rating (PAR)
Classification of occlusion
Incisors
Buccal segments/ molar relationship
Incisor classification
Class I
Class II ***
Assess the position **
Class I incisors
Lower incisor tip **
Class II div 1
Lower incisor tip occludes behind cingulum plateau of upper incisor
**
Class II div 2
Lower incisor tip occludes behind cingulum plateau of upper incisor
Upper central incisors are retroclines
Class III incisors
Lower incisor tip occludes in front of cingulum plateau of upper incisor
Class I molar
Mesiobuccal cusp tip of upper 6 occludes in mid-buccal groove of lower 6
Class II molar
Mesiobuccal cusp tip of upper 6 occludes anterior to the mid-buccal groove of lower 6
Class II molar
Mesiobuccal cusp tip of upper 6 occludes anterior to the mid-buccal groove of lower 6
1/2 unit class II
Mesiobuccal cusp tip of upper 6 occludes anterior to the mid-buccal groove of lower 6, where they are cusp to cusp
-not great functionally
Class III molar
Mesiobuccal cusp tip of upper 6 occludes posterior to the mid-buccal groove of lower 6
1/2 unit class III
Mesiobuccal cusp tip of upper 6 occludes cusp to cuspto the disto-buccal groove of lower 6
Possible causes of root resorption
Gender Habits Alveolar bone density Endodontically treated Continuous forces Type of tooth movement Degree of force Jiggling forces
Ways to treat crowding
Extractions
Expand arch - quadhelix
Distalise upper molars
-headgear
-fixed appliance e.g. pendulum appliance, distal jet, temporary anchorage
Enamel stripping (up to 0.25mm but straighten first)
What effects can headgear achieve?
Extraoral anchorage: holds posterior teeth in position, preventing mesial movement of anchorage unit
Traction: applies distal force to posterior teeth to achieve distal tooth movement
-also used to restrict growth of maxilla forwards and downwards
-requies larger forces for longer periods of time
Headgear safety
Must have at least two safety features incorporated to prevent ocular injuries (otherwise can cause blindness!)
-e.g. Masel strap, snap-away safety release mechanism
