Dentition
____: when both primary & secondary teeth are present. This occurs at age ____.
Mixed dentition
6-9 yrs old
What is the angle classification for occlusion based on?
The relationship between the mesiobuccal cusp of the maxillary 1st molar and the buccal groove of the mandibular 1st molar
Describe the Sella-Nasion,A-point (SNA) angle?
*100 bonus points for the normal range
Indicates the relative position of the maxilla relative to the cranial base
*normal = 82 ± 3 degrees
What is the goal of orthognathic surgery?
To establish Class I occlusion (or improve occlusion) while optimizing aesthetics (ideal facial proportions).
Define "Mesial"
Toward dental midline
What are the first teeth to erupt?
*Double points for the age
Incisors
*6 months
The mesial buccal cups of the maxillary 1st molar is mesial to the buccal groove of the mandibular 1st molar.
What is the occlusion?
Class II occlusion
Describe the Sella-Nasion,B-point (SNB) angle?
*100 bonus points for the normal range
Indicates the relative position of the mandible relative to the cranial base.
*normal = 80 ± 3 degrees
When is the appropriate timing for orthognathic surgery?
At skeletal maturity;
14-16 for females & 16-18 for males
_____ :angulation of apex toward the tongue.
_____ :angulation of apex toward the lips.
Retroclination: angulation of apex toward the tongue
Proclination: angulation of apex toward the lips
Define “cusp” and “groove” as they relate to dental anatomy.
Cusp: protruding portion of occlusal surface
Groove: intruding portion of occlusal surface
Dental compensation is the tendency of the teeth to tilt in a direction which minimizes malocclusion.
How do the upper & lower incisors tilt to compensate for class III occlusion?
Proclination of the upper incisors
Retroclination of the lower incisors
Draw & describe the Frankfort horizontal plane.
Line from the infraorbital rim through the porion (uppermost lateral point on the roof of the external auditory meatus).
Name at least 3 key elements to obtain while planning orthognathic surgery.
1. Complete medical and dental history
2. Oral exam
3. Aesthetic evaluation
4. Photos
5. Cephalometric evaluation
6. Casts, occlusal splints
What is incisal show?
The amount of vertical show of maxillary central incisor in repose.
In standard international numbering:
- Which tooth is labeled 1?
-Which tooth is labeled 17?
1: Right maxillary 3rd molar
17: left mandibular 3rd molar
How does maxillary retrusion / midface hypoplasia affect the SNA?
What type of occlusion is typically associated with this retrusion?
Decreased SNA
Class III malocclusion
Cephalometric analysis shows SNA angle of 70 degrees (normal 80 to 82 degrees) and SNB angle of 79 degrees (normal 79 to 80 degrees). Which of the following is the most likely diagnosis?
Maxillary deficiency
Where is the occlusal plane?
Describe occlusal cant.
Between the molars & the incisors
Discrepancy of occlusal plane from horizontal
Describe overbite vs. overjet.
Overbite: VERTICAL relationship of the maxillary and mandibular tooth apices
Overjet: HORIZONTAL relationship of the maxillary and mandibular tooth apices
What is the nomenclature for the 20 primary teeth?
Letter system: A-P
A: R Maxillary 2nd molar
J: L Maxillary 2nd molar
K: L Mandibular 2nd molar
T: R mandibular 2nd molar
What is the key exam finding in retrognathia?
What is the associated SNB angle and occlusion?
Decreased mandibular projection
Decreased SNB
Class II malocclusion
Cephalometric analysis shows SNA angle of 83 degrees (normal = 82 ± 3 degrees) and SNB angle of 85 degrees (normal = 80 ± 3 degrees). Which of the following is the most likely cause of this patient's deformity?
Mandibular prognathism
A 22-year old male presents with elongation of the lower ⅓ of the face, excess gingival show, >4 mm incisor show, and lip incompetence.
What is the general diagnosis?
What does the primary surgical correction involve?
Vertical maxillary excess
Le Fort I osteotomy
What is Apertognathia?
Open bite - vertical gap between maxillary and mandibular teeth when the mouth is closed