Classification of malocclusion Flashcards
A brachycephalic relationship is when?
Larger than average cranial width.
Broad, square head shape with low mandibular plane angle
A brachyfacial relationship is when?
Broad square face with strong chin, flat lips, low mandibular plane angle, straight profile
Dolicocephalic is?
Narrower cranial width, low and narrow shape with high mandibular plane angle
Dolicofacial?
Low, narrow face with high mandibular plane angle
Convex profile with poor chin and anterior-posterior height imbalance
What is the lipline?
The amount of tooth and gingival tissue exposed at rest
What is lip incompetence?
When the patient can’t have the lips in contact while relaxed without showing muscle strain
What are the three possible shapes of the dental arches?
Elliptical, square, or tapering
What is angle classification based off of?
The relationship between the MB cusp of the maxillary 1st molar and the buccal groove of the mandibular 1st molar
What is class 1 occlusion?
Normal occlusion where the MB cusp of the max 1st is aligned with the buccal groove of the mandibular 1st
Coincident midlines and normal overbite/overjet
What is class 1 malocclusion?
Normal molar relationship but may have crowding, misalignment, etc.
What is class 2 occlusion?
Buccal groove of the mandibular 1st is too far distal
Describe the 2 divisions of class 2 malocclusion
Division 1 is when the maxillary anteriors are proclined and there is a large over jet
Division 2 is when the maxillary anteriors are retroclined and a deep overbite exists
What is class 3 malocclusion?
The buccal groove of the 1st molar is too far mesial
What is over jet?
The distance between the labial part of the mandibular incisors and the incisal edge of the maxillary incisors
What is a functional crossbite?
Occlusal interference causing the mandible to shift anteriorly or laterally to achieve maximum occlusion
What is overbite?
Amount of overlap of the mandibular anteriors by the maxillary anteriors when measured perpendicular to the occlusal plane
What is an open bite?
When there is no vertical overlap
What happens in ankylosis?
There is fusion of the teeth and alveolar bone leading to teeth in the infra version position, they don’t fully erupt
What type of radiograph do orthodontists use?
Lateral cephalometric
When someone has a hyper divergent skeletal pattern what does this mean?
Excessive divergence of the skeletal planes
What oral abnormalities are seen in those with hyper divergent skeletal pattern?
Steep mandibular plane angel, long lower face with open bite, lip incompetence, and class 2 occlusion
What is dentoalveolar protrusion?
Anterior teeth are positioned forward of the normal limits of the basal bone, can occur on one arch or both
What is true or skeletal class 3?
Retrusive maxillary arch or preotrusive mandibular arch
How do you correct a skeletal class 3?
Surgery
What is a pseudo class 3?
When dental interference causes a functional shift.
What is a class 3 subdivision?
Normal class 1 on one side and class 3 on the other
When planes are hypo divergent what kind of relationship is formed?
Deep overbite
What is a normal overbite relationship?
10-20% overlap or about 1 mm
What happens at 100% overbite?
Palatal impingement
Why use a space maintainer?
If a root is developing slowly, maintain space for it. Only used on one tooth
When to use a distal shoe?
When the primary 2nd molar is lost early, the permanent 1st hasn’t erupted yet. Leaves space for that molar
What do you use with bilaterally missing teeth?
Nance holding arch
What does a nance holding arch do?
Holds the molars back so if one is lost prematurely, space remains
What is the biggest contributor to occlusion and dental issues?
Genetics
