Exam 1 - Etiology Flashcards
Skeletal dental muscular heredity environment
are all causes for
malocclusion
Number of teeth size of teeth alterations in eruption attachment levels trauma
are all what problems that cause malocclusion
dental problems
total absence of teeth
Usually associated with systemic diseases like Ectodermal dysplasia
anodontia
absence of many teeth usually 6 or more
usually associated with systemic diseases like ectodermal dysplasia
oligodontia
congenital absence of only a few teeth
hypodontia
What are common congenitally missing teeth?
Disturbances in initial stages of tooth formation
usually the most distal tooth of the same group:
molars, 2nd premolars, lateral incisors
Canines are rarely missing
What are common supernumerary teeth?
Disturbances in initiation and proliferation stages
Most frequently found in midline MESIODENS
multiple supernumerary teeth - cleidocranial dysplasia
can cause spacing, impacted or crowding
Primary canines are usually affected
tendency for the space to close
incisors tend to drift distally
mesial drift of permanent molars due to this
premature loss of primary tooth
small teeth - large jaws
most likely spacing
large teeth - small jaws
crowding
The size of the upper teeth is not proportional to the size of the lower teeth (5% of the population)
Tooth size (Bolton) Discrepancy
For a permanent tooth to erupt what must happen?
Overlaying bone and primary root must resorb and the erupting tooth must make its way through the gingiva
What can obstruct the eruption?
Supernumerary teeth, sclerotic bone, and heavy fibrous gingiva
Which teeth are most likely to be impacted?
third molars, upper canines, and lower second premolars
An impacted tooth can cause root resorption of the neighboring teeth or develop cysts.
Don’t leave them unattended
Malposition of a tooth bud can lead to eruption in a wrong place
Most likely upper first molars, upper cuspids and lower second premolars
Ectopic eruption
When teeth are in switched position with the neighboring tooth
Most frequently Max cuspid and bicuspid
Transposition
Fusion between bone and root surface
Impossibility to erupt or mobilize
Teeth can’t reach occlusal level
Ankylosis
If there is loss of attachment teeth become mobile and start flaring
What can they develop?
Diastemas and increased overjet
What can be a cause of an anterior diastema
A thick fibrous low inserted frenum
Skeletal problems
Skeletal class that can cause issues
Class III
Class II
Skeletal open
Skeletal deepbite
What systemic conditions are present with altered growth?
Gigantism
Acromegaly
Both can cause excessive mandibular growth
Pierre robin syndrome
Can cause deficient mandibular growth
Achondroplasia
Can cause deficient growth of cartilage
Mastication Swallowing breathing Abnormal muscle activites - tongue posture Habits - thumb sucking Mandibular posture Occlusal trauma
Functional problems
Swallowing stages
0-3 years old - tongue interpositon is normal
A persistent infantile swallowing pattern after 6 years old with alter shape and size of arches
What odes tongue thrusting cause?
open bite
tooth movement
diastemas
altered growth
Breathing
Nasal breathing contributes to middle face normal growth
What can obstruct?
large adenoid tissue masses creates upper airway obstruction
Posture change
patient lowers and protrudes tongue
Opens mouth to breathe
Adenoid facies
narrow - long face
Protruding teeth lips separated at rest dried lips constricted maxilla underdeveloped cheeckbones
Abnormal muscle activities
Lip Trap
Lack of labial tone
Cheek biting
proclines upper incisors, retroclines lower incisors
Proclined incisors
decrease transverse dimesnsion in both arches
Seen in primary dentition
Pointy canines
Unstable MIP
SHIFT to the side or forward to a more stable bite
Mandibular posture
Can cause unilateral posterior crossbite
Limits transverse growth of upper arch
Lateral mandibular shift (mandible)
causes anterior crossbite
Skeletal class I
Limits sagital maxilary growth
If not corrected –> skeletal class III
Forward shift (mandible)
Mouth breathing can cause
posterior cross bite
