Angles Classification of Occlusion - Ch 20
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Questions and Answers

What is the ideal relationship between the teeth and jaws, providing optimum form and function?

Ideal occlusion

What is the classification that indicates the mesiobuccal cusp of the maxillary 1st molar should line up with the mesiobuccal groove of the mandibular 1st molar?

Class I

What is the term for bad occlusion or poor alignment?

Malocclusion

Malocclusion can include dental malocclusions and skeletal malocclusions, or a combination of both (teeth and jaws)

<p>True</p> Signup and view all the answers

Abnormalities in the size or arrangement of teeth can cause?

<p>Malocclusion</p> Signup and view all the answers

What can result from abnormalities in the relative sizes of or alignment of the dental arches?

<p>Malocclusion</p> Signup and view all the answers

What can different types of poor occlusal relationships acquired naturally or from incomplete orthodontic treatment result in?

<p>Malocclusion</p> Signup and view all the answers

Who originally classified the skeletal relationships between the maxillary and mandibular arches, and when?

<p>Dr Edward Angle, 1887</p> Signup and view all the answers

Occlusal classifications are defined by describing the relationship between which teeth?

<p>Maxillary and mandibular 1st molars</p> Signup and view all the answers

If the maxillary and mandibular molars are missing, which teeth can alternatively be used to classify occlusion?

<p>The maxillary and mandibular canines</p> Signup and view all the answers

What is the ideal skeletal relationship with no abnormal tooth alignment or discrepancies?

<p>Class I Occlusion</p> Signup and view all the answers

Each Angle's classification is identified by how many factors?

<p>3</p> Signup and view all the answers

What is the relationship between the mandibular and maxillary teeth in a Class I occlusion?

<p>There is maximum contact between the mandibular and maxillary teeth</p> Signup and view all the answers

What is the molar relationship in a Class I (ideal occlusion)?

<p>The mesiobuccal cusp of the maxillary 1st molar occludes in the mesiobuccal groove of the mandibular 1st molar</p> Signup and view all the answers

What is the canine relationship in a Class I (ideal occlusion)?

<p>The cusp tip of the maxillary canine should rest in the facial embrasure of the mandibular canine and 1st premolar</p> Signup and view all the answers

What is the facial relationship in a Class I (ideal occlusion)?

<p>The maxillary posterior teeth located one cusp buccal to the mandibular posterior teeth</p> Signup and view all the answers

What is the ideal anterior teeth relationship with a Class I (Ideal occlusion)?

<p>The maxillary anteriors vertically overlap mandibulars by 1-2mm (overbite). There should be contact between the maxillary and mandibular teeth. The labial surfaces of maxillary teeth 1-2mm anterior to mandibular anteriors (overjet)</p> Signup and view all the answers

Does Class I (ideal occlusion) have rotated teeth, abnormal spaces or crowding?

<p>False</p> Signup and view all the answers

With Class I Malocclusion (Neutrocclusion), what is the molar relationship?

<p>The mesiobuccal cusp of the maxillary 1st molar occludes in the mesiobuccal groove of the mandibular 1st molar (same as Class I Ideal occlusion)</p> Signup and view all the answers

With Class I Malocclusion (Neutrocclusion), what is the canine relationship?

<p>The maxillary canine occludes between the mandibular canine and 1st premolar (same as Class I Ideal occlusion)</p> Signup and view all the answers

Is the molar and canine relationship of the Class I Ideal occlusion & Class I Malocclusion (Neutrocclusion) the same?

<p>True</p> Signup and view all the answers

What is the facial profile of a Class I malocclusion?

<p>Mesognathic</p> Signup and view all the answers

What type of alignment discrepancies will be exhibited with a Class I malocclusion?

<p>-Crowding -Spacing -Malpositioning</p> Signup and view all the answers

Class II malocclusion is also known as?

<p>Distocclusion</p> Signup and view all the answers

With a Class II malocclusion, the mandible is in what relationship with the maxilla?

<p>Distal (retruded)</p> Signup and view all the answers

What is the molar relationship of a Class II distocclusion?

<p>The mesiobuccal cusp of maxillary 1st molar occludes with the interdental space between the mandibular 2nd premolar and 1st molar</p> Signup and view all the answers

What is the canine relationship of a Class II distocclusion?

<p>The maxillary canine occludes mesial to the mandibular canine</p> Signup and view all the answers

There are ____ divisions of a Class II Distocclusion.

<p>2</p> Signup and view all the answers

Describe the characteristics of a Class II: Division I.

<p>-All anterior teeth are flared -Protrusion -Maxillary incisors are in labioversion -&quot;Buck teeth&quot;</p> Signup and view all the answers

Describe the characteristics of a Class II: Division II.

<p>-Lateral incisors are tipped labially and mesially -Central incisors (retruded) inclined lingually (in linguoversion)</p> Signup and view all the answers

What is the difference between Division I and II of Class II Distocclusion?

<p>Division I: All maxillary incisors are flared. Division II: Central incisors are retruded, laterals flared and tipped mesially.</p> Signup and view all the answers

What is the facial profile of a Class II?

<p>Retrognathic</p> Signup and view all the answers

Describe the mandible's relationship to the maxilla in a retrognathic profile.

<p>The mandible is retruded (distal) in relationship to the maxilla</p> Signup and view all the answers

With a Class II, due to discrepancies of teeth and maxillary dental protrusion, what may be required?

<p>Removal of teeth</p> Signup and view all the answers

With a Class II, in regards to the mandibular retrognathism, what may be going on with the mandible?

<p>The lower jaw bone has not grown as much as the upper jaw bone, may need early growth guidance</p> Signup and view all the answers

Class II Dental malocclusion may be more difficult to treat due to the skeletal disharmony.

<p>True</p> Signup and view all the answers

Class III Mesiocclusion: the mandible is in a ____________ relationship to the maxilla.

<p>mesial</p> Signup and view all the answers

In a Class III mesiocclusion, is the mandible retruded or protruded?

<p>Protruded</p> Signup and view all the answers

What type of face shape is a Class III Mesiocclusion?

<p>Prognathic</p> Signup and view all the answers

With a Class III mesiocclusion, what is the molar relationship?

<p>The MB cusp of the maxillary 1st molar occludes in the interdental space between the distal cusp of the mandibular molar and mesial cusp of 2nd molar</p> Signup and view all the answers

What is the canine relationship in a Class III mesiocclusion?

<p>The maxillary canine occludes distal to the space between the mandibular canine and 1st premolar</p> Signup and view all the answers

What is the discrepancy of jaws where the lower jawbone has outgrown the upper jaw called?

<p>Class III Dental malocclusion</p> Signup and view all the answers

What is the ideal facial relationship between maxillary and mandibular teeth?

<p>The maxillary teeth should be facial to the mandibular teeth</p> Signup and view all the answers

When the mandibular teeth are facial to the maxillary teeth, usually due to a size discrepancy between maxillary and mandibular jaws, what is this condition called?

<p>Crossbite: Bilateral posterior</p> Signup and view all the answers

A crossbite that occurs only on one side, may be a few teeth, may have a variety of causes, is referred to as?

<p>Unilateral crossbite</p> Signup and view all the answers

Increased horizontal measure of bite between maxillary and mandibular incisors is called?

<p>overjet</p> Signup and view all the answers

Increased vertical measure of bite between maxillary and mandibular incisors is referred to as?

<p>Overbite</p> Signup and view all the answers

What is the ideal range of overjet?

<p>2-3 mm</p> Signup and view all the answers

How is overjet measured?

<p>With a probe, between the labial surface of the mandibular incisors to the lingual surface of the maxillary incisors</p> Signup and view all the answers

Is it normal to have overjet?

<p>True</p> Signup and view all the answers

What is the vertical distance by which the maxillary incisors vertically overlap the mandibular incisors called?

<p>Overbite</p> Signup and view all the answers

What is the ideal range of overbite?

<p>2-3 mm</p> Signup and view all the answers

Incisal edges of the maxillary teeth are within the incisal third of the facial surfaces of the mandibular teeth, is what level of overbite?

<p>Moderate</p> Signup and view all the answers

Maxillary teeth are within the cervical third of the mandibular teeth, is what level of overbite?

<p>Severe</p> Signup and view all the answers

Incisal surfaces of maxillary teeth occlude with incisal surfaces of mandibular teeth, there is no overlap. This is considered?

<p>Edge-to-edge anterior teeth</p> Signup and view all the answers

Molars and premolars occlude in a cusp-to-cusp rather than in a cusp-to-groove relationship, this is considered?

<p>end-to-end posterior teeth</p> Signup and view all the answers

Tooth has assumed a position labial to normal is called?

<p>labioversion</p> Signup and view all the answers

Tooth is positioned buccal to normal is referred to as?

<p>buccalversion</p> Signup and view all the answers

Tooth is positioned lingual to normal is called?

<p>linguoversion</p> Signup and view all the answers

Tooth is elongated (positioned) beyond the line of occlusion is known as?

<p>supraversion</p> Signup and view all the answers

Tooth is depressed below (short of) the line of occlusion is referred to as?

<p>Infraversion</p> Signup and view all the answers

Tooth is twisted (turned) or rotated in its position is called?

<p>Torsoversion</p> Signup and view all the answers

Tooth is tipped mesially is known as?

<p>Mesioversion</p> Signup and view all the answers

Tooth is tipped distally is referred to as?

<p>Distoversion</p> Signup and view all the answers

A tooth that erupts outside its normal position within the arch, commonly a maxillary canine, is called?

<p>Ectopic eruption</p> Signup and view all the answers

Study Notes

Ideal Occlusion

  • Defined as the optimal relationship between teeth and jaws, ensuring maximum function and aesthetic form.

Types of Occlusion

  • Class I (Ideal Occlusion): Mesiobuccal cusp of maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar.
  • Class I Malocclusion (Neutrocclusion): Same molar and canine relationship as Class I, but misalignment or discrepancies present.
  • Class II Malocclusion (Distocclusion): Mandible positioned distally to the maxilla. Molar relationship involves the maxillary first molar occluding between the space of the mandibular second premolar and first molar.
  • Class III Malocclusion (Mesiocclusion): Mandible is positioned mesially to the maxilla, resulting in a protruded jaw relationship.

Malocclusion

  • Malocclusion Types: Includes both dental and skeletal malocclusions, often resulting from mismatches in tooth size/arrangement or jaw alignment.
  • Common Causes: Misalignment can arise from crowding, spacing, or incomplete orthodontic interventions.

Classification System

  • Angle’s classification established by Dr. Edward Angle in 1887, based on the skeletal relations of maxillary and mandibular arches.
  • Occlusal classifications use the first permanent molars to define relationships, but canines may be used if molars are absent.

Class II Malocclusion Divisions

  • Division I: All anterior teeth protruded, labioverted maxillary incisors ("buck teeth").
  • Division II: Lateral incisors tipped labially/mesially, central incisors are retruded.

Facial Profiles

  • Class I: Mesognathic profile.
  • Class II: Retrognathic profile; mandible is retruded relative to the maxilla.
  • Class III: Prognathic profile; mandible protruded.

Measurements of Occlusion

  • Overjet: Horizontal measurement between labial surfaces of mandibular incisors and lingual surfaces of maxillary incisors, considered normal at 2-3 mm.
  • Overbite: Vertical overlap of maxillary incisors over mandibular incisors, ideally 2-3 mm.
  • Levels of Overbite:
    • Moderate: Maxillary incisors within the incisal third of mandibular teeth.
    • Severe: Maxillary teeth within the cervical third of mandibular teeth.

Common Terminology

  • Open Bite: No contact between anterior teeth; can be anterior or posterior.
  • Crossbite: When mandibular teeth are more facial than maxillary teeth, can be bilateral or unilateral.

Tooth Positioning

  • Labioversion: Labial position beyond normal.
  • Buccalversion: Positioned buccally to normal.
  • Linguoversion: Positioned lingually to normal.
  • Supraversion: Elongated beyond the occlusal line (hypereruption).
  • Infraversion: Depressed below the occlusal line.
  • Torsoversion: Twisted or rotated.
  • Mesioversion & Distoversion: Tipped mesially or distally, respectively.
  • Ectopic eruption: Tooth erupts outside normal position, often requiring orthodontic treatment if untreated.

Additional Facts

  • Class II requires potential tooth removal or growth guidance for retrognathic profiles.
  • Skeletal discrepancies may complicate treatment in malocclusions.

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Test your knowledge on the Angles classification of occlusion with these flashcards. This quiz covers the definition of ideal occlusion, Class I occlusion, and malocclusion among other important concepts in oral anatomy and physiology.

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