Questions and Answers
What are the components in a class III malocclusion?
What is the skeletal pattern of a class III malocclusion?
Mandible is protruded/in line in relation to the maxilla.
What is the technique used to diagnose skeletal patterns?
Bimanual palpation technique.
What is the definition of a class III incisal relationship?
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What is the definition of a class III molar relationship?
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What is the aetiology of a class III malocclusion?
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What are the skeletal factors that cause a class III malocclusion?
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What are the soft tissue factors that cause a class III malocclusion?
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What are the dento-alveolar factors that cause a class III malocclusion?
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What are the main other factors that cause a class III malocclusion?
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What are the components needed in diagnosing a class III patient?
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What are the important factors when recording history when diagnosing a class III patient?
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What are the three hard tissue factors that need to be assessed?
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What is used to assess the antero-posterior skeletal relationship?
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What is used to assess the vertical skeletal relationship?
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What is used to assess the transverse skeletal relationship?
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What are the two components that need to be examined in intra-oral examination?
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What is intra-arch assessment?
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What is inter-arch assessment?
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What are the intra-oral features of class III malocclusion?
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How to measure displacement?
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Why must displacements be treated?
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What are the radiographs used for diagnosis of a class III malocclusion?
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What are the indications for treatment of a class III malocclusion?
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What are the components in the assessment before treatment in class III malocclusion?
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What are the treatment options for class III malocclusion?
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What treatment can be provided to early treatment timing?
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What are the indications for interceptive treatment?
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What are the problems with early interceptive treatment?
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What are the components in the URA?
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When can camouflage be used for treating class III malocclusion?
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What are the techniques for dental camouflage?
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What treatment do late treatment timing patients need?
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When is orthognathic surgery indicated?
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Can you start camouflage and then go for surgery?
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Study Notes
Class III Malocclusion Overview
- Class III malocclusion is characterized by a skeletal pattern where the mandible is positioned forward relative to the maxilla.
- Patients often exhibit a reduced overjet and an incisal relationship where the lower incisors meet anterior to the palatal cingulum of the upper incisors.
Components of Class III Malocclusion
- Skeletal Factors: Includes a retrusive maxilla, protrusive mandible, or a combination of both.
- Incisal Relationship: Lower incisal edges are positioned ahead of the upper incisors leading to a reverse overjet.
- Molar Relationship: Mesio-buccal cusp of the upper first molar is located distal to the lower molar's mesiobuccal groove.
Diagnostic Techniques
- Bimanual Palpation: A technique for establishing skeletal patterns by placing fingers in the concavities of the maxilla and mandible, assessing relative positioning of points A and B.
Aetiology of Class III Malocclusion
- Involves skeletal, soft tissue, dentoalveolar, and genetic components affecting the dental structure and overall morphology.
- Skeletal Factors: Often include a combination of a hypoplastic maxilla and a prognathic mandible.
- Dentoalveolar Factors: Can manifest as fewer teeth in maxillary arches, narrow upper arches, bilateral crossbites, and uneven tooth positioning affecting occlusion.
Radiographic Diagnosis
- Essential radiographs include Orthopantomogram (OPG), lateral cephalogram, and optionally upper standard occlusal views.
Treatment Considerations
- Different timing in treatments:
- Early Treatment: Often involves interceptive approaches before significant skeletal growth causes further complications.
- Intermediate Treatment: Focuses on growth modification when the patient is still growing but may require different strategies than camouflage.
- Late Treatment: Involves orthognathic surgery and fixed appliances, with camouflage usually not viable.
Treatment Options
- May include jaw repositioning techniques, dental camouflage using fixed appliances, or orthognathic surgery for severe cases.
- Common soft tissue compensations can include proclining and retroclining adjacent teeth to adjust the bite without changing skeletal relationships.
Intraoral Examination Features
- Key assessments include incisor relationships, overjet, overbite, centrelines, molar relationships, and displacement monitoring.
- Clinical observation can identify potential crossbites and disruptions in occlusal harmony.
Indications for Treatment
- Presence of significant skeletal discrepancies, aesthetic concerns, functional problems, and potential growth dynamics may indicate the need for treatment.
- Awareness of patient’s history and concerns regarding aesthetics and functionality is crucial in planning.
Interceptive Treatments
- Active Removable Appliances (URA): Focus on correcting crossbites, managing overcrowding, or addressing incisor positioning while the patient is still growing.
- Can lead to significant improvements and stability in occlusion if done at the appropriate growth stage.
Orthognathic Surgery
- Typically indicated for patients with pronounced skeletal discrepancies who are no longer growing.
- Procedures can dramatically change facial profiles and improve life quality by allowing for more functional occlusion.
Prognosis
- Good prognosis for stability if the upper and lower teeth can be aligned properly with careful treatment timing and monitoring.
- Early intervention often leads to improved long-term outcomes with less risk of requiring more extensive surgeries later on.
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Description
Test your knowledge on Class III malocclusion with these flashcards. Each card covers essential components such as skeletal patterns, incisal relationships, and the bimanual palpation technique. Perfect for dental students wanting to sharpen their understanding of orthodontics.