Contemporary orthodontics Flashcards
What are the three types of appliances?
1) Growth modification - aims to alter growth
2) Move teeth within existing bony envelope - fixed appliances and removable appliances
3) Retainers
What do we want from any appliance?
Comfortable treatment
Acceptable appearance during treatment
Acceptable treatment time
Lowest possible risk during treatment
Long term stability
What are functional appliances?
Removable appliances that are worn for 22/hrs a day and removed for cleaning, eating and sport.
What is a twin block functional appliance?
Two pieces (upper and lower) that touch when the patient bites and force the patient to bite forward.
What is a medium opening activator?
Single piece that patient bites into - metal clips on the upper 6 and 4, patient bites on lower part forcing the patient to bite forward.
What is a fixed functional appliance?
Pt wears this full time, it attached from an upper molar to a lower tooth, the piston arms force the patient to bite forward causing muscles to stretch.
What do functional appliances do and what do they need to work?
A growing and compliant patient - usually done 11-14 when the patient is at their pubertal growth phase.
Muscle stretch causes proclined lower incisors and retroclined upper incisors that reduces overjet and changes molar relationship from class II to class I.
Can also correct a deep bite when using a medium opening activator the molars are disoccluded so over erupt.
What are the risks and benefits of functional appliances?
Risks - failure rate through non compliance
Can impact QoL through speech, eating, discomfort
Benefits - corrects class II malocclusion - overjet and molar relationship
Can have a small improvement in facial appearance and vertical effect
Can be used with fixed appliance and headgear
What can headgear be used for?
Correcting class II malocclusions
Can be used in different directions - depending if you just want to pull the teeth distally or restrain maxillary growth at the same time.
Can correct an anterior open bite as it can have an upwards pull on the molars
Has to be worn for 14 hours and when asleep- not used at school, and not when eating or sports/activities
What are the benefits and risks of headgear?
Corrects class II malocclusion - overjet and molar relationship
Little change to facial appearance - good for high angle class II
Can be used in combination with functional/fixed appliances with increased vertical proportions
When do we want to see a patient with a class III dental/skeletal pattern?
Aged 8-9
What do we aim to do in class III growth modification?
1) Promote maxillary growth
2) Restrict mandibular growth
3) Combination
What is the most commonly used class III growth modifier?
Protraction face mask - a frame that sits on the chin and forehead with elastics to fixed or removable maxillary appliance pulling the maxilla forward.
Need to wear >14 hrs a day, most of the time except school
What are the benefits and risks of protraction face mask?
Benefits - corrects class III malocclusion
Can promote change to facial appearance
Risks - failure due to non-compliance
Can be difficult to get sufficient hours
Impact QoL
May not prevent need for further tx later on 1/3 need ortho later - but is easier and 1/3 may need OGN surgery.
What is a reverse functional appliance?
Aims to push mandible back and maxilla forward however in reality the jaw sits open so there is mostly a vertical change rather than antero posterior.
They are not popular in the UK as they are bulky and difficult to wear.