Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My BDS4 > Class III malocclusions > Flashcards

Class III malocclusions Flashcards

1
Q

What defines malocclusions?

A

the incisor relationship

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define a class III malocclusion?

A

Lower incisor edge occludes anterior to the cingulum plateau of the upper central incisor

The overjet is (usually) reduced or reversed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Do all C3 malocclusions have reversed/reduced overjets?

A

no
- can have the lower incisors occluding just slightly anterior to the upper cingulum

  • can have edge to edge bite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What causes class III malocclusions? (3)

A
  • Strong genetic link

Environmental factors;
* Cleft lip and palate – surgery early on = restricted growth of maxilla from scarring
* Acromegaly – increased growth hormone affects mandible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What skeletal features do patients with a C3 malocclusion usually present with?

What are these caused by?

A

usually have a class 3 antero-postero relationship however can also be class 1 (rarely class 2)

Caused by;
Small maxilla, large mandible, or both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What vertical skeletal pattern/features do patients with a C3 malocclusion usually present with?

how is the vertical skeletal pattern measured?

A

Can be associated with Average, increased or reduced vertical proportions

Assess;
- FMPA
- Facial height proportions
(Lateral ceph useful to assess)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the dental features of a C3 malocclusion? (5)

A
  • Class III incisors
  • Often but not always C3 molars
  • Often reversed overjet
  • Reduced overbites or AOB present
  • Crossbites (Ant or post)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the alignment of the upper and lower arches in px’s with C3 malocclusion. (4)

A
  • Crowded maxilla
  • Aligned or spaced mandible
  • Dentoalveolar compensation commonly seen = proclined upper incisors ad retroclined lower incisors
  • Tendency for displacement to achieve posterior contact
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What dental features indicate that a C3 patient is more difficult to treat? (4)

A
  • More than 1-2 teeth in anterior crossbites
  • Skeletal element aetiology
  • A greater A-P discrepancy
  • Presence of anterior openbite
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the relevance of soft tissues in terms of C3 malocclusions?

A

Not usually associated with cause however it does encourage dentoalvolar compensation
- Tongue proclines upper incisors
- Lower lip retroclines the lower incisors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why should we treat class 3 malocclusions? (5)

A
  • Aesthetics
  • appearance of teeth
  • Profile concerns
  • Dental health:
  • Attrition: Displacing jaw = wear of the labial face of upper and palatal face of the lowers
  • Gingival recession
  • Mandibular displacement = long term TMJ problems
  • Function
  • Speech: advise px that Correcting the malocclusion doesn’t always fix the speech
  • Mastication
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If a C3 malocclusion is corrected will the patients speech sound like someone without a C3 malocclusion?

A

not always - advise px that Correcting the malocclusion doesn’t always fix the speech

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the implications of long term mandibular displacement?

A

TMJ dysfunction/pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why do we not carry out major/irreversible treatment on patients when they are still growing?

A

Growth is unfavourable as mandible growth continues longer than maxillary growth = worsens C3 incisor relationship/undo treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

During which period of growth do the jaws undergo a growth spurt?

A

during the pubertal growth spurt
(large variation of when this occurs in patients)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how can we predict a px’s pubertal growth spurt?

A

Height and weight charts

17
Q

What do we do if we are unsure if a patient is in their pubertal growth spurt?

A

do nothing and wait

18
Q

list the treatment options for a C3 malocclusion. (5)

A

accept and monitor

interceptive treatment

growth modifications

orthodontic camouflage

orthodontics + orthognathic surgery

19
Q

In what C3 patients is accept and monitor indicated? (3)

A

Mild cases
- Used when Px has n concerns
- Used when px has no Dental health indications (displacement or attrition)

20
Q

In what C3 patients is interceptive tx indicated? (3)

A
  • when Class III incisors have developed due to early contact on permanent incisors (i.e. mandibular displacement)
  • In correction of anterior crossbite in mixed dentition has the advantage that further forward mandibular growth may be counter-balanced by some dento-alveolar compensation.
  • Only suitable for correcting a lateral incisor crossbite if permanent canines are high above lateral roots
  • Delay if canines have dropped down into the buccal position as this is a risk of resorption to lateral incisor
21
Q

what dental feature indicates stability of the dentition post treatment?

A

the presence of a desired/good overbite before treatment

22
Q

In what C3 patients are growth modifications indicated? (1)

A

those who are still growing

23
Q

What does growth modification treatment aim to do?

A

Reducing/redirecting mandibular growth and encourage maxillary growth

24
Q

How can we modify growth? (5)

A

Functional appliances;
* Chin cup (historic)
* Frankel III (not as commonly used)
* Reverse Twin block

  • Protraction headgear +/- rapid maxillary expansion
  • Protraction headgear +/- bollard implants
25
Q

Why are frankel III’s not as commonly used to modify the growth of a C3 malocclusion? (3)

A
  • it’s a one-piece appliance which is hard to wear all the time
  • has lots of acrylic/wire = trauma to mucosa
  • is prone to breakage
26
Q

in what age of patient does Protraction headgear +/- rapid maxillary expansion have the best effects in growth modification?

A

mixed dentition - 8-10 years

27
Q

What are the aims of Protraction headgear +/- rapid maxillary expansion in growth modification? (2)

A

Pulls maxilla forward with anchorage to the facemask

When used alongside rapid maxillary expansion = splits midpalatal and the circummaxillary suture = easier to pull maxilla forward

28
Q

how many hours per day should Protraction headgear +/- rapid maxillary expansion be used?

A

minimum 14 hours

29
Q

where are upper bollard implants placed?

A

infrazygomatic region

30
Q

where are lower bollard implants placed?

A

region of lower canines

31
Q

Describe what the aims of orthodontic camo of a C3 malocclusion are.

A

accept the underlying skeletal base relationship and aim for class 1 incisor relationships (Achieved with fixed appliances only)

32
Q

In what C3 patients is orthodontic camo indicated? (5)

A

Px’s which have;
- Stopped growing
- Mild/moderate C3 (ANB>0 degrees)
- Increased/average overbite at start of tx
- Can edge to edge bite at start of tx
- Little/no DA comp (don’t want px to start tx with v proclined upper incisors and retroclined lowers)

33
Q

Describe the usual extraction pattern for orthodontic camouflage treatment. (2)
what other factor influences this?

A
  • Extract further back in uppers e.g. 5’s
  • Extract further forward in lowers e.g. 4’s

Dental health can dictate pattern e.g. XLA teeth with poorer prognosis (heavily filled, carious etc)

34
Q

what tx can we offer to a C3 patient who is unhappy with the appearance of their teeth however cannot have definitive tx since they are still growing?

A

Can align the upper arch only before px stops growing to satisfy complaints
- once px stopped growing you can correct the jaw relationship

35
Q

what is orthognathic surgery?

A

Orthognathic surgery is surgical manipulation of the mandible and / or maxilla to produce optimal dentofacial aesthetics and function

36
Q

In what C3 patients is orthognathic surgery indicated? (3)

A
  • Pt with aesthetic or functional concerns
  • Growth completed
  • Moderate/Severe skeletal discrepancy
  • A-P
  • Transverse
  • Vertical
37
Q

List the treatment steps for a c3 patient undergoing orthognathic surgery and orthodontic tx. (3)

A
  • Presurgical orthodontics
  • Level, align, coordinate and decompensate
  • Eliminate rotation and crowding
  • correct angulation
    upper incisors = 109 degree angulation
    lower incisors = 90 degree angulation
  • Orthognathic surgery to reposition the jaws
  • Mandible or Mandible ± Maxilla
  • Post surgical Orthodontics (approx. 6 months)
38
Q

What angulation of upper and lower incisors do we aim for in pre-surgical orthodontics prior to orthognathic surgery?

A

upper incisors = 109 degree angulation
lower incisors = 90 degree angulation

39
Q

How long is orthodontic treatment post orthogathic surgery?

A

approx 6 months

My BDS4 (57 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions