Malocclusion Class 1 Flashcards

1
Q

Class 1 malocclusion

A

Lower incisor edge lies on cingulum plateau of upper central incisor

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2
Q

Incidence of class 1

A

60%

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3
Q

Skeletal pattern in class 1
AP RELATIONSHIP?

A

Full range, mostly average but also increased and reduced face height

Sk1 normal incisors -normal incisors ,
Mild sk class 2 - normal U , L proclined,
Mild sk class 3 - Proclined U , L Retroclined

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4
Q

Dentoalveolar compensation

A

A mechanism through which soft tissues (lips, tongue, cheeks) produce more class 1 incisor relatiohship when AP skeletal pattern is SK 2 or SK3.

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5
Q

Dento- alveolar compensation for class 3 SK.

A
  • Proclined upper incisors
  • Retroclined lower incisors

They tend to go towards class 1

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6
Q

Class 2 Sk Dento Alveolar compensation

A
  • Retroclined upper incisors
  • proclined lower incisors

They tend to go towards class 1

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7
Q

Transverse Dimension
Facial asymmetry

A
  • Biological variation - usual situation
  • pathological- condylar hyperplasia
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8
Q

Facial asymmetry
I/O

A
  • centre line discrepancies
  • Posterior cross bites +- ( mandibular displacements)

If you see one of these go back and check facial asymmetry.

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9
Q

Soft tissues?

A

-The soft tissues pattern in class 1 is generally favourable and doesn’t change facial growth

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10
Q

Malocclusion class 1
COMMON FEATURE

A
  • Crowding
  • Spacing
  • Bimaxillary proclination
  • local factors
  • pathology
  • Anterior open bite
  • posterior open bite
  • local cross bite
  • unilateral cross bite
  • Bilateral cross bite
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11
Q

Crowding because? And tx

A
  • very common problem
  • too much tooth tissue for arch size
  • mild crowding, Non XT
  • moderate to severe- XT of premolar +-EOT
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12
Q

Spacing why and tx?

A
  • smalll teeth on normal Jaws
  • Normal sized teeth on large jaws
  • missing teeth
    Tx- Close space or redistribute space
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13
Q

Bimaxillary proclination why?

A
  • Upper and lower incisors proclined.
  • influenced by soft tissues
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14
Q

factors?

A
  • variation in tooth number - extra teeth supernumeraries or hypodontia
  • variation in tooth form- Macrodonts, microdonts,
  • Abnormalities in tooth position - can be canine but more likely in Class 2 div 2. transposition ( most transposition involves canine
  • local abnormalities of soft tissue : frenum
  • local pathology : Cyst

-AOB - Sk cause - due to increase lower face height, Habbit due to digit sucking , Soft tissues due to tongue activity ( seen in Down’s syndrome pt) ( hard to diagnose, usually diagnose of exclusion)
- SK and soft tissue AOB almost always symmetrical , digit effect asymmetrical.

-Habit- Digit habit can produce AOB sometimes,
Posterior cross bite

-Transverse occlusion problem ( one arch is bigger than other) - can occur in any class

-CAUSE OF Posterior cross bite- narrow maxilla i.e- transverse sk discrepency. Digit sucking habit- discuss the reasons, local problem often related to local crowding.

   - Crossbites unilateral (May associated with mandibular displacement) always check. Mandibular displacement , bilateral

   -Bilateral cross bite
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15
Q

Aim and objectives Class 1 Malocclusion

A
  • understand /Aetiology of class 1 malocclusion
  • understand problem tha may require tx class 1 mal
  • know some key points about tx of class 1 mal
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16
Q

What is normal transverse arch relationships?

A
  • upper arch wider than lower
  • correct bucco lingual occlusion
17
Q

Class 1 Incisor inclination

A
  • It varies
  • normal incisor angle
  • Normal Upper/ proclined lower
  • Proclined upper/ Retroclined lower
18
Q

Soft tissue have caused Proclination of lower incisors only when ?

A
  • Class 1 Incisor despite of SK class 2
19
Q

Skeletal and soft tissues AOB

A
  • Sk and soft tissue AOB always symmetrical , Digit sucking effect often asymmetrical
20
Q

Soft tissue Open bite commonly found in?

A
  • due to tongue position in Down syndrome
21
Q

Unilateral cross bite

A
  • Unilateral crossbite may associated with mandibular displacement
22
Q

When you see crossbite check what?

A
  • always check mandibular displacement