Class II Division 1 Malocclusions Overview
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Questions and Answers

What is the definition of Class II division 1 malocclusions?

The lower incisor edges lie posterior to the cingulum plateau of the upper incisors.

What is always present in Class II division 1 malocclusions?

Increased overjet.

What is the prevalence of Class II division 1 malocclusions?

15 - 20%.

What are the four aetiological factors of Class II division 1 malocclusions?

<p>Skeletal, dental, soft tissues, and habits.</p> Signup and view all the answers

What is the skeletal pattern (anthro-posterior relationship) of Class II division 1 malocclusions?

<p>Usually skeletal Class II, mainly with retrognathic mandible (80%).</p> Signup and view all the answers

What is the Skeletal pattern (vertical relationship) of Class II division 1 malocclusions?

<p>Vertical skeletal pattern can vary from reduced, average to increased vertical dimensions.</p> Signup and view all the answers

What is the main dental factor for Class II division 1 malocclusions?

<p>Crowding.</p> Signup and view all the answers

How does crowding lead to Class II division 1 malocclusions?

<p>Crowding leads to upper 1s being pushed labially from the arch.</p> Signup and view all the answers

What are the dental features of Class II division 1 malocclusions?

<p>Increased overjet, buccal occlusion class II, crowding/spacing, and overbite can be deep/increased or reduced/incomplete.</p> Signup and view all the answers

What position do teeth normally lie in?

<p>Teeth erupt into a zone of equilibrium with surrounding soft tissues.</p> Signup and view all the answers

How does the lower lip affect the eruption of upper teeth?

<p>The lower lip must lie on upper teeth controlling eruption; if not, upper teeth can erupt proclined.</p> Signup and view all the answers

What are the reasons for the lower lip being unable to control the eruption of upper teeth?

<p>Skeletal relationship with mandible too far back and incompetent lips due to increased vertical dimension.</p> Signup and view all the answers

How does the muscular tone of the lip affect the eruption of upper teeth?

<p>Lack of muscle tone leads to incompetent lips, allowing uncontrolled eruption of upper teeth.</p> Signup and view all the answers

What is the thumb-sucking habit that causes Class II division 1 malocclusions?

<p>Thumb sucking applies pressure to the upper teeth causing proclination and retroclination of lower anteriors.</p> Signup and view all the answers

Why are Class II division 1 malocclusions treated?

<p>For aesthetics, increased risk of trauma, and psychological well-being.</p> Signup and view all the answers

What are the treatment options for Class II division 1 malocclusions?

<p>Accept, growth modification, headgear, camouflage, and orthognathic treatment.</p> Signup and view all the answers

What must you do when accepting a Class II division 1 malocclusion?

<p>Explain the risks to the patient (e.g., trauma) and provide a mouth guard for contact sports.</p> Signup and view all the answers

What is the purpose of headgear?

<p>To restrict A-P growth of the maxilla and allow 'catch up' growth of the mandible.</p> Signup and view all the answers

What is orthognathic treatment?

<p>Use of jaw surgery and fixed appliances to correct severe skeletal discrepancies.</p> Signup and view all the answers

Who are the best candidates for growth modification?

<p>Well motivated, actively growing patients with moderate to severe anterior-posterior discrepancy.</p> Signup and view all the answers

What two changes do functional appliances cause?

<p>Dental and skeletal changes.</p> Signup and view all the answers

What are the properties of the dental changes caused by functional appliances?

<p>70% of changes seen, upper incisors retrocline, lower incisors procline.</p> Signup and view all the answers

What are the properties of the skeletal changes caused by functional appliances?

<p>30% of changes seen, some mandibular growth, very little restraint of the maxilla.</p> Signup and view all the answers

Study Notes

Class II Division 1 Malocclusions

  • Class II division 1 malocclusions defined by lower incisor edges being posterior to the cingulum plateau of upper incisors.
  • Prevalence of Class II division 1 malocclusions ranges from 15% to 20% of the population.

Key Characteristics

  • Increased overjet is a consistent feature; upper incisors may be proclined or average in inclination.
  • Malocclusion can be caused by skeletal, dental, soft tissue factors, and habits.

Aetiological Factors

  • Skeletal Factors:

    • Predominantly skeletal Class II, often associated with retrognathic mandible (80% of cases).
    • Mild cases may present as skeletal Class I.

  • Dental Factors:

    • Crowding is the primary dental issue; can lead to labial positioning of upper incisors.
    • Features include increased overjet, buccal occlusion class II, variations in overbite, and potential spacing due to non-crowding.

  • Soft Tissue Factors:

    • The lower lip influences upper incisor position through its resting position.
    • Incompetent lips due to increased vertical dimension can exacerbate proclination of upper incisors.

  • Habits:

    • Thumb sucking leads to proclination of upper teeth and retroclination of lower incisors, further increasing overjet and potentially causing open bite.

Treatment Considerations

  • Treatment is indicated for aesthetics, increased trauma risk (overjet greater than 9 mm), and psychological well-being.
  • Options include acceptance (for mild cases), growth modification, headgear, camouflage, or orthognathic surgery.

Growth Modification

  • Functional appliances utilize forces from oral musculature to enact dental and skeletal changes—commonly includes removable and fixed types.
  • Best candidates for growth modification are well-motivated, actively growing with moderate to severe anterior-posterior discrepancies.

Functional Appliance Properties

  • Dental Changes:

    • 70% of changes noted include the retroclination of upper incisors and proclination of lower incisors, effectively removing Class II relationship.

  • Skeletal Changes:

    • Approximately 30% of changes observed, including some mandibular growth and minimal restraint on maxillary growth.

Key Functional Appliances

  • Twin Block Appliance:

    • Composed of two sections, provides forward jaw posturing and can expand the upper arch.

  • Headgear:

    • Applied force to restrict maxillary growth while allowing mandibular catch-up growth; typically required for 14 hours a day.

Camouflage Treatment

  • Established when treating mild to moderate skeletal Class II patterns by working around the underlying Class II relationship, which may involve extractions.

Orthognathic Treatment

  • Involves jaw surgery in conjunction with fixed appliances, primarily used for adults with completed growth, severe skeletal discrepancies, or poor facial aesthetics.

Conclusion

  • Class II division 1 malocclusions showcase a range of dental, skeletal, and soft tissue characteristics, requiring careful evaluation for appropriate treatment planning.

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Description

Explore the characteristics and aetiological factors of Class II Division 1 malocclusions. This quiz covers skeletal, dental, and soft tissue influences, as well as prevalence rates in the population. Test your knowledge on this common dental issue.

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