Podcast
Questions and Answers
What value indicates a labiolingual inclination where the gingival area of the crown is more toward the lingual?
What value indicates a labiolingual inclination where the gingival area of the crown is more toward the lingual?
What is the angle between the crown tangent of the upper incisors and the line perpendicular to the occlusal plane?
What is the angle between the crown tangent of the upper incisors and the line perpendicular to the occlusal plane?
If the upper anterior teeth are too upright, what risk does this pose to the occlusion?
If the upper anterior teeth are too upright, what risk does this pose to the occlusion?
What should be the interincisal angle between the axes of the incisors in normal occlusions?
What should be the interincisal angle between the axes of the incisors in normal occlusions?
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What occurs if the upper incisors are in linguoversion despite correct posterior occlusion?
What occurs if the upper incisors are in linguoversion despite correct posterior occlusion?
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What is the crown torque of the lower incisor?
What is the crown torque of the lower incisor?
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Which angle represents the interincisal angle between the crown tangents of the upper and lower incisors in normal occlusions?
Which angle represents the interincisal angle between the crown tangents of the upper and lower incisors in normal occlusions?
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If the labiolingual inclination of the upper incisors has negative values, what is the state of the occlusion?
If the labiolingual inclination of the upper incisors has negative values, what is the state of the occlusion?
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What is the primary purpose of classifying malocclusion?
What is the primary purpose of classifying malocclusion?
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Which classification method is primarily qualitative?
Which classification method is primarily qualitative?
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What is the definition of malocclusion?
What is the definition of malocclusion?
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Which of the following best describes skeletal classification in malocclusion classification systems?
Which of the following best describes skeletal classification in malocclusion classification systems?
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What distinguishes quantitative methods of classifying malocclusion?
What distinguishes quantitative methods of classifying malocclusion?
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Which classification involves a comprehensive consideration of incisor relationships?
Which classification involves a comprehensive consideration of incisor relationships?
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Which of the following classification methods is a modification of Angle's classification?
Which of the following classification methods is a modification of Angle's classification?
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What is a key feature of Ackerman & Proffit classification?
What is a key feature of Ackerman & Proffit classification?
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What is indicated if the upper canines and premolars are inclined at virtually the same angle?
What is indicated if the upper canines and premolars are inclined at virtually the same angle?
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Which of the following statements about rotated teeth is true?
Which of the following statements about rotated teeth is true?
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What results from tightly contacting teeth in normal occlusion?
What results from tightly contacting teeth in normal occlusion?
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What is a key aspect of achieving correct occlusion?
What is a key aspect of achieving correct occlusion?
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What consequence occurs when the canines no longer maintain a Class I relationship?
What consequence occurs when the canines no longer maintain a Class I relationship?
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What is described by the terms 'gingival portions of the teeth are more pronounced buccally than the occlusal portions'?
What is described by the terms 'gingival portions of the teeth are more pronounced buccally than the occlusal portions'?
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What is a significant factor contributing to occlusal interferences?
What is a significant factor contributing to occlusal interferences?
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How does the inclination of posterior teeth affect the overall occlusion?
How does the inclination of posterior teeth affect the overall occlusion?
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What is Class III sub-division characterized by?
What is Class III sub-division characterized by?
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What is a de-merit of Angle's classification?
What is a de-merit of Angle's classification?
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Which modification introduced a new naming system for Angle's classifications?
Which modification introduced a new naming system for Angle's classifications?
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In Dewey's modification, which type corresponds to well-aligned teeth and an edge-edge relationship?
In Dewey's modification, which type corresponds to well-aligned teeth and an edge-edge relationship?
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Which of the following is NOT one of Andrew's six keys?
Which of the following is NOT one of Andrew's six keys?
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What characterizes Class II in skeletal classification?
What characterizes Class II in skeletal classification?
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Which type in Dewey's Class I modification involves crowded maxillary anterior teeth?
Which type in Dewey's Class I modification involves crowded maxillary anterior teeth?
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What is a common feature of Angle’s classification system?
What is a common feature of Angle’s classification system?
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What is one of the major characteristics included in Ackerman's and Proffit's classification system?
What is one of the major characteristics included in Ackerman's and Proffit's classification system?
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Which of the following describes 'yaw' in Ackerman's and Proffit's classification?
Which of the following describes 'yaw' in Ackerman's and Proffit's classification?
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What does the term 'pitch' refer to in the context of Ackerman's and Proffit's classification?
What does the term 'pitch' refer to in the context of Ackerman's and Proffit's classification?
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What is a criticism of the Ackerman and Proffit classification?
What is a criticism of the Ackerman and Proffit classification?
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Which plane is NOT used when evaluating rotations in Ackerman's and Proffit's classification?
Which plane is NOT used when evaluating rotations in Ackerman's and Proffit's classification?
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What does roll describe regarding the vertical position of teeth?
What does roll describe regarding the vertical position of teeth?
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What aspect does the Ackerman and Proffit classification primarily elaborate on?
What aspect does the Ackerman and Proffit classification primarily elaborate on?
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Which feature characterizes the esthetic line of occlusion?
Which feature characterizes the esthetic line of occlusion?
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What effect does an excessive curve of Spee have on the upper teeth?
What effect does an excessive curve of Spee have on the upper teeth?
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According to Andrews, what is the maximum acceptable depth of the mandibular curve of Spee?
According to Andrews, what is the maximum acceptable depth of the mandibular curve of Spee?
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What is the consequence of a reverse curve of Spee on the upper jaw?
What is the consequence of a reverse curve of Spee on the upper jaw?
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In a flat curve of Spee, how is the intercuspation described?
In a flat curve of Spee, how is the intercuspation described?
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What happens to lower incisors in cases with an excessive curve of Spee?
What happens to lower incisors in cases with an excessive curve of Spee?
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What is true about midlines in normal adult occlusion?
What is true about midlines in normal adult occlusion?
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How is an ideal upper arch shape described in normal adult occlusion?
How is an ideal upper arch shape described in normal adult occlusion?
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What characterizes the occlusion of a 13-year-old prior to adult occlusion?
What characterizes the occlusion of a 13-year-old prior to adult occlusion?
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Study Notes
Normal Occlusion
- Normal occlusion is characterized by a specific relationship between the upper and lower teeth.
- Andrew's six keys define the criteria for normal occlusion.
Andrew's Six Keys of Occlusion
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Key 1: Molar Interarch Relationship:
- The mesiobuccal cusp of the upper first molar fits into the groove between the mesial and medial buccal cusps of the lower first molar.
- The mesiolingual cusp of the upper first molar occludes in the central fossa of the lower second molar.
- The distal marginal ridge of the upper first molar occludes with the mesial marginal ridge of the lower second molar.
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Key 2: Mesiodistal Crown Angulation:
- The gingival aspect of the tooth's long axis is positioned more distally than the occlusal aspect.
- The angulation varies based on the type of tooth (e.g., canines exhibit the greatest angulation while premolars exhibit the least).
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Key 3: Labiolingual Crown Inclination:
- The angle between a tangent to the tooth's long axis and a line perpendicular to the occlusal plane is crucial.
- If the gingival portion of the tooth is more lingual, the result is a positive value. Conversely, a more buccal gingival position results in a negative value.
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Key 4: Rotations:
- No tooth should be rotated; rotated molars and premolars increase space while rotated incisors may decrease space.
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Key 5: Tight Contacts, No Spacing:
- In the absence of tooth or intermaxillary discrepancies, the contact points should abut.
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Key 6: Curve of Spee:
- The curve of Spee refers to the overall occlusal plane's curve.
- A flat curve is desirable; an excessive curve or reverse curve is undesirable, negatively affecting space and potentially causing crowding.
- Various examples and diagrams showcasing normal/abnormal occlusion and radiographs are provided.
Incorrect Occlusion
- If the upper anterior teeth are too upright, the labiolingual crown inclinations are negative, leading to an unstable occlusion.
- Canine guidance becomes insufficient and posterior teeth drift mesially.
- Interdental spacing can incorrectly be associated with intermaxillary tooth size discrepancies.
Occlusal Changes After Orthodontic Treatment
- Clinical images illustrate changes post-treatment, including a shift in the incisor position and space changes.
Labiolingual Inclination of Posterior Teeth (Optimal Occlusion)
- The tangential angles of posterior teeth on the facial surfaces to a line perpendicular to the occlusal plane are crucial for optimal occlusion.
- The gingival portions tend to be buccal than the occlusal areas.
- The mandibular canines and premolars typically have similar inclinations, with molar inclinations slightly more buccal, progressively increasing from the canine to the second molar.
Classification of Malocclusion
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Angle's Classification:
- Based on the relationship between the mesiobuccal cusp of the maxillary first molar and the buccal groove of the mandibular first molar.
- Classes include Class I, Class II, and Class III.
- Subdivisions exist for each class.
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Modifications of Angle's Classifications:
- Lischer's introduction of neutrocclusion, distocclusion, and mesiocclusion
- Dewey's divisions for Class I, Class II, and Class III.
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Skeletal Classification:
- Class I - Maxilla and mandible are in harmony.
- Class II - Maxilla is ahead of the mandible.
- Class III - Maxilla is behind the mandible.
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British Standard Classification of Incisor Relationship:
- Based on incisor relationship (not molar) and divisions.
- Class I - Lower incisors occlude with or just below upper cingulum plateau.
- Class II - Lower incisor edges lie posterior to the upper incisor cingulum plateau.
- Division 1 - Proclined upper central incisors
- Division 2 - Retroclined upper central incisors
- Class III - Lower incisor edges are anterior to the upper incisor cingulum plateau.
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Canine Classification:
- Class I - Mesial slope of upper canine aligns with distal slope of lower canine.
- Class II - Mesial slope of upper canine is anterior to distal slope of lower canine.
- Class III - Mesial slope of upper canine is posterior to distal slope of lower canine.
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Simon's Classification (1926):
- Used anthropologic planes (Frankfort horizontal, orbital, and mid-sagittal) to assess dental arch relationships.
- Describes deviations from protraction to retraction.
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Ackerman & Proffit Classification (1960):
- Overcame limitations of Angle's classification by including broader characteristics.
- Used a Venn diagram model for classifying malocclusions.
- Included aesthetic line of occlusion and rotational values in defining specific malocclusions.
Additional Information
- Molar positions and interrelationships (Class I, II, III).
- Descriptions of different types of malocclusion and specific details regarding each classification and the different characteristics of malocclusion.
- Overbite, overjet, and other details about the teeth.
- Diagrammatic and pictorial descriptions (radiographs, models, etc.) to visualize different occlusal and skeletal patterns.
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Description
This quiz focuses on the concept of normal occlusion, including the specific relationship between upper and lower teeth. It also covers Andrew's six keys that define the criteria for normal occlusion, detailing their significance and characteristics. Test your understanding of these foundational concepts in dentistry.
