Etiology of Malocclusions- Dr. Retrouvey (FINAL) Flashcards
Predisposing factors to malocclusion include:
- Genetics (primary factor)
- Functional matrix
- Disturbances in embryologic development
- Traumas
Primary etiologic sites include:
- Neuromuscular system
- Bone
- Teeth
- Soft tissues
List diseases associated with the following primary etiologic sites:
- Neuromuscular system
- Bone
- Teeth
- Soft tissues
- Cerebral palsy (results in severe malocclusion)
- Osteogenesis Imperfeta (COL1A1 & COL1A2)
- Ectodermic dysplasia
- Scleroderma
Disturbances in embryologic development may be due to:
Teratogens
May interfere with cellular differentiation during pregnancy:
Teratogens
Some examples of teratogens include:
- Alcohol
- Drugs
- Pollution
- Poor nutrition
We used to think cleft lip & palate could be due to teratogens but the idea have shifted now to them being due to:
Genetics
Most common craniofacial abnormality:
Cleft lip & palate
Crouzon syndrome is a type of:
Craniostynostosis
Crouzon syndrome (craniostynostosis syndrome) is caused by:
Early fusion of sutures
-the lower jaw develops normally
-the orbits close early
Crouzon syndrome is characterized by:
1.Bulging eyes
2. Small maxilla
What is a typical treatment for Crouzon syndrome?
Distraction osteogenesis
Crouzon syndrome (Craniosynostosis) is purely a ____ disease
Bony
Disease characterized by underdevelopment of the midface & eyes that seem to bulge from their sockets
Crouzon syndrome
Disease characterized by underdeveloped cheek & jaw bones, a prominent nose, broad mouth & characteristically small chin with steep lower jaw angle:
Treacher-Collins
When the maxilla & mandible are both underdeveloped this is considered:
Bimaxillary retrusion
In dentistry when you have syndromes, you typically have:
Hypodontia (exception Cleidocranial dysplasia)
Disease characterized by:
-delayed closure (ossification) of the space between the bone of the skull (fontanels)
-premature closing of coronal suture
-protruding jaw
-protruding brow bone
-wide nasal bridge due to increased space between the eyes
-high arched palate or possible cleft palate
-short stature
-scoliosis of spine
Cleidocranial dysplasia (CCD)
Describe the mandible of a patient who has CCD:
Typically a class III (because of hypertrophic mandible)
Dental abnormalities of CCD patient include:
Failure to loose baby teeth & delayed or absent percent teeth, slow eruption of secondary teeth
In osteogenesis imperfecta, the _____ is affected:
Dentin
What class of malocclusion is often seen in OI patients?
Class III malocclusion (as well as posterior open bite)
-Midline deviation
-asymmetry repercussion on the condyles
-posterior open bite
-lack of chewing capability
These are all characteristic of:
Osteogenesis imperfecta
Type of osteogenesis imperfect that characterized by less bone but still good bone; majority of OI patients
Type I
Types of osteogenesis imperfecta characterized by weak bone with lots of fractures; more severe
Type III & IV
What is one of the most significant aspects of osteogenesis imperfecta?
Dentinogenesis imperfecta
If one OI member of the family has DI:
All the other OI members of that family have DI as well
Discuss the prevalence of DI in the following types of OI patients:
Type I:
Type IV:
Type III:
Type I= 20%
Type IV= 40-60%
Type III= 100%
In what disease discussed is all of the teeth NOT affected in the same manner?
Dentinogenesis imperfecta
Down syndrome can be characterized with underdevelopment or hypoplasia of the midface region, meaning:
Smaller & retrusive maxilla (contributes to class III malocclusion)
Is the maxilla or mandible smaller due to Down syndrome?
Maxilla (mandible is normal)
The open bite seen in a patient with down syndrome is due to:
The large/thick tongue pushing on the teeth, not genetics
Condylar are:
Growth sites
Condition in which one condyle is absent, creating significant malocclusion:
Condylar dysplasia
-we see the muscle compensations in this situation to keep patient semi-functional
A lot of syndromic patient have significant:
Cranial base alterations
Position & projection of the upper & lower jaws rely on:
Cranial base
Types of malocclusion:
30% of people have ____ occlusion
Normal occlusion
Types of malocclusion:
50-55% of people have ____ occlusion
Class I malocclusion
Types of malocclusion:
15% of people have ____ occlusion
Class II malocclusion
Types of malocclusion:
1-4% of people have ____ occlusion
Class III malocclusion
Malocclusion occurs in ____ dimensions
3
angle classification of occlusion is based on:
AP relationships
Retrognathic (overbite)=
Class II
Prognathic (underbite)=
Class III
Are most class II malocclusions a result of maxillary prognathism or mandibular retrognathism?
Mandibular retrognathism
40% of our class two patients are actually:
Bimaxillary retrusive
Even among the same class of malocclusions, there is:
Phenotypic diversity
A very common type of class III malocclusion is called characterized by overjet & overbite:
Edge-to-edge
-wears down incisors
The prevalence of malocclusions depends on the:
Population
What percent of southeast Asians display a malocclusion?
15%
What percent of middle easterns display a malocclusion?
10%
What percent of Indians display malocclusions?
~1%
What percent of europeans display a malocclusion?
1-4%
The genetics of class III malocclusions are focused on:
Mandibular prognathism
Family & twin sides of genetics of class III malocclusions suggest a ____ as a primary cause of class III malocclusions
Polygenic model
What aspects contribute to the polygenic model, responsible for class III malocclusion?
Genes + environment + condylar cartilage
What is used to determine the chromosome loci associated with the genetics responsible for class III malocclusion?
linkage analysis studies
If you catch a class III malocclusion at 8-9 years of age and intervene in the mixed dentition bringing them back to a class I profile, what will result?
Some correct nicely, some do not
(unpredictable)
Deep bite is a _____ problem:
Vertical
A unique characteristic to open birds is that sometimes you have a ___ stage in which they can resolve themselves
transitory
Deep & open bites have _____ etiologies
Multifactorial
