Ortho - Class II Division I (A) Flashcards
Define a class II division I incisor relationship?
Where the lower incisal edges lie posterior to the cingulum plateau of the upper incisors
There is an increased overjet
The upper central incisors are proclined or of average inclincation
Why should we treat a C2D1 incisor relationship? (2)
- Poor aesthetics
- Dental health concerns i.e. trauma (risk increased if px also incompetent)
What IOTN score does an overjet of 9mm get?
5a
What causes a C2D1 incisor relationship? (4)
- Skeletal pattern
- Soft tissues
- Dental factors
- Habits
What A/P skeletal pattern is a C2D1 incisor relationship usually associated with?
class 2 AP relationship
What vertical skeletal pattern is a C2D1 incisor relationship usually associated with?
variety of low, high and average
What is the normal SNA value?
SNA = 81 +/- 3
What is the normal SNB value?
SNB = 78 +/- 3
What is the normal ANB value?
ANB = 3 +/- 2
What is the normal MxP/MnP value?
27 +/- 4
What is the normal UI/MxP value?
109 +/- 6
What is the normal LI/MxP value?
93 +/- 6
How do we measure the LAFH/TAFH?
What is the ideal value clinically and on a lateral ceph?
Measured via;
Nasion – anterior nasal spine
Anterior nasal spine – menton
Clinically =50/50
LC = 55%
Why are lips incompetent? (don’t contact at rest) (2)
- prominent incisors
and/or
- underlying skeletal pattern
What are incompetent lips usually accompanied by? (1)
lip trap
Why is it important to make an anterior oral seal?
Incompetent lips = no anterior oral seal
lip trap can cause proclination of upper anterior teeth during grown and development
How do we achieve an anterior oral seal? (3)
- Lip to lip seal achieved by the activity of circum-oral musculature and mandible postured to allow lips to meet
- Lower lip drawn up behind the upper incisors and tongue is place forwards between the incisors and lower lip
- Or both in combination
What is the consequence of having habitually parted lips?
dry gingivae and worsens pre-existing gingivitis
Provide examples of non-nutritive sucking habits (5)
- Thumb
- Fingers
- Blanket
- Lip
(combination)
What do the effects of a sucking habit depend on? When does it start to cause dental related problems? (3)
Effects depend of duration and intensity;
Sucking for 6 or more hours per day = increased problems
What are the occlusal features of a sucking habit? (4)
- Proclined upper anterior incisors
- Retroclined lower anterior incisors
- Localised AOB or incomplete openbite
- Narrow upper arch (potentially unilateral posterior CB)
Caused by mandible being held in a lower position with the buccinator unopposed
How do we treat those with a sucking habit/the dental implications of a sucking habit? (3)
- Stop the habit
- Reinforcement of instructions
- Glove or ointment
- Removable habit breaker
- Fixed habit breaker: palatal arch with a goalpost bheing the upper incisors
These are more successful - Allow spontaneous improvement
- Difficult if a laip trap present
- Treat residual malocclusion
Provide examples of how we stop a sucking habit. (4)
- Reinforcement of instructions (first line tx)
- Glove or ointment
- Removable habit breaker
- Fixed habit breaker: palatal arch with a goalpost bheing the upper incisors
These are more successful
List the treatment options for a class II div 1 malocclusion. (5)
- Accept
- Attempt growth mods – act on underlying skeletal bases to improve growth
- Simple tipping of teeth
- Camouflage – fixed appliances correct incisor relationship without influencing the growth of the jaws
- Orthognathic surgery
What is camouflage treatment?
fixed appliances correct incisor relationship without influencing the growth of the jaws
When is no treatment acceptable? (2)
- In a mildly increased overjet
- In a significant overjet but patient not concerned
Provide a mouthguard to reduce trauma risk
What must we advise patients with C2D1 relationships that don’t want treatment as a child?
must advise patients that treatment in the future is more difficult once the patient gets older and has stopped growing.
What are functional appliances?
Appliances which utilise, eliminate or guide forces of muscle function, tooth eruption and growth to correct a malocclusion
When are functional appliances used?
During growth – coincide with pubertal growth spurt
What are functional appliances mostly used for?
Mostly for class 2 div 1’s
- However can use for C2D2
What are the 2 ways we can use functional appliances. Describe when each are used.
- Early use = 10 years old (2 phase tx – 2nd phase when all permanent teeth erupted)
- Later use = late mixed or early permanent (1 phase tx – straight on to fixed appliances)
What are the advantages of early use of functional appliances? (3)
- Reduce trauma risk
- Address aesthetic concerns earlier i.e. going to secondary school and self-conscious
- Better compliance with appliance wear
What are the disadvantages of early use of functional appliances? (2§)
- Effects not maintained long term
- Treatment time is increased as 2 phases required
List the types of functional appliances for C2D1. (4)
- Removable
- Tooth borne = twin block
- Tooth borne = activator/bionator
- Soft tissue borne = frankel (II)
- Fixed
- Herbst
How do functional appliances work in reducing C2D1’s?
They restrain maxillary growth and posture the mandible down and forwards to encourage mandibular growth
When can functional appliances be used in treatment of increased oversets? (3)
- It’s a very mild class I or II
- The overjet is caused by proclined and spaced incisors
- The overbite is favourable
When do we carry out orthognathic surgery?
Once growth is complete:
- Females = minimum 16 (17,18)
- Males = 18/19/20
Why do we surgical techniques in orthodontics?
When there is a severe anteroposterior skeletal discrepancy or vertical discrepancy
