Questions and Answers
What is the definition of the mesiobuccal groove of the mandibular first molar?
What describes Division 1 in malocclusion?
Which of the following indicates a prognathic maxilla?
What happens to the mandible during downward and forward growth?
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In Class 2 Division 1, what is the lip behavior usually like?
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What is a characteristic of the lower lip in Class 2 Division 2?
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What are some treatment options for Class 2 malocclusion?
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What is the main focus of camouflage treatment?
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How is the force applied in headgear for upper molar distalization?
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The malleable force of headgear typically allows for _____ mm of distal movement.
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Study Notes
Overview of Class 2 Malocclusion
- Class 2 malocclusion characterized by the mesiobuccal groove of the mandibular first molar located distally to the mesiobuccal cusp of the maxillary first molar.
Divisions of Class 2 Malocclusion
- Division 0 indicates normal inclination of upper incisors.
- Division 1 features proclined upper incisors with increased overjet.
- Division 2 consists of retroclined upper central incisors, possibly with increased overbite.
Skeletal Etiology
- Prognathic maxilla exhibits SNA angle greater than 85 degrees.
- Retrognathic mandible presents SNB angle less than 75 degrees.
- An ANB angle greater than 4 degrees suggests a class 2 relationship.
- Includes unit length discrepancies and varying vertical and transverse skeletal discrepancies.
Mandibular Growth Patterns
- Downward and forward rotation of the mandible can increase vertical dimension and lead to shallower overbites, often viewed as unfavorable.
- Clockwise (CW) rotation describes downward and backward growth; counterclockwise (CCW) rotation indicates horizontal growth, usually producing deeper overbites.
Soft Tissue Etiology for Class 2 Division 1
- Lips typically incompetent at rest and require active positioning to achieve a lip seal, employing various muscle straining techniques.
Soft Tissue Etiology for Class 2 Division 2
- Characterized by a resting lower lip that covers a significant amount of the upper incisors.
Dental Etiology
- Division 1 features proclined upper incisors and may involve discrepancies as noted in Bolton analysis.
Treatment Planning Considerations
- Optimal treatment timing coincides with periods of mandibular growth, capitalizing on favorable growth patterns.
- Ongoing growth assessment can dictate whether treatment remains favorable or shifts toward unfavorable conditions.
Favorable vs. Unfavorable Growth
- Favorable growth refers to horizontal mandible growth (up and forward rotation).
- Unfavorable growth describes vertical increases, characterized by downward and backward mandible rotation.
Treatment Options for Class 2 Malocclusion
- Possible approaches include camouflage, growth modification, and surgical correction.
Camouflage Treatment Strategy
- Aimed at managing mild skeletal discrepancies by shifting teeth rather than adjusting skeletal relationships, often involving limited dentoalveolar compensation.
Natural Camouflage Characteristics
- Natural camouflage is often achieved through biological means, including dentoalveolar adjustments where lower incisors are proclined and upper incisors remain upright or retroclined.
Options for Camouflage Treatment
- May involve using upper removable appliances, molar distalization techniques, or extractions depending on the specific needs of the case.
Upper Removable Appliance Characteristics
- Effective in mild class 2 or class 1 skeletal bases, ideal for proclined upper incisors with spacing.
Roberts Retractor in Camouflage
- Specifically targets proclined upper incisors while addressing lower lip positioning using Adam clasps on molars for better retroclination.
Distalization of Molars Protocol
- Necessary to ensure the complete buccal segment is distanced without mesializing of the upper molars, typically requiring fixed appliances afterward.
Pendulum Appliance for Molar Distalization
- Delivers distalizing force to molars and may inadvertently affect adjacent teeth due to reciprocal forces.
Headgear Options for Molar Distalization
- Utilizes facebow and neck strap for application, achieving 2-3 mm of movement under ideal conditions and up to 5-6 mm with extractions.
Force Application in Headgear
- Placement of force varies with treatment goals, with above occlusal plane forces promoting intrusion, below promoting extrusion, and centered forces facilitating pure distalization.
Challenges with Headgear
- Potential issues include patient compliance, unintended tooth movements, biological variability, and discomfort during use.
Extraction Considerations
- Involves strategic choices regarding upper 4's and lower 5's, typically pertaining to individual cases in treatment planning.
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Description
Test your knowledge on Class 2 malocclusion with these flashcards covering key terms and definitions. Learn about the specific divisions and skeletal etiology in this essential area of dental education. Perfect for dental students preparing for examinations.
