Occlusion and Malocclusion Flashcards
Define ideal occlusion
Anatomically perfect arrangement of teeth
Define normal occlusion
Acceptable variation from ideal occlusion
List 4 point about normal occlusion
no crowding
teeth are well aligned
class I incisor relationship
class I molar relationship
Define Class I incisor relationship
The incisal edges of the lower incisors occlude with or lie immediately below the cingulum of upper central incisors
Define Class I molar relationship
The mesio-buccal cusp of the maxillary 1st molar occludes in line with the buccal groove of the mandibular 1st molar
the maxillary 1st molar is positioned slightly posterior in relative to the mandibular 1st molar
define malocclusion
variation from ideal occlusion which has dental and/or physiological implications
How many classes of malocclusions are there?
3
Define Class I malocclusion
Bite is normal but upper teeth slightly overlap the lower teeth
Define Class II malocclusion
upper teeth severely overlap the bottom teeth
MB cusp of max 1st molar more mesially placed
define Class II div I malocclusion
class 2 molars with normally inclined or proclined maxillary central incisors
define Class II div II malocclusion
class 2 molars with retroclined maxillary incisors
what does a class II div I malocclusion increase?
overjet measurement due to proclined incisors
define class III malocclusion
lower jaw protrudes forward
MB cusp of max 1st molar distally positioned
define overjet
horizontal distance between upper and lower incisors
define overbite
upper teeth overlap lower teeth
name 3 genetic causes of malocclusions
skeletal pattern
size of jaws and teeth
certain syndromes
how many classes of skeletal classes are there?
3
Class I
Class II
Class III
what are the 3 dimensions of clinical examination?
antero-posterior
transverse
vertical
name 2 ways the face can be assessed vertically?
using the rule of thirds
measuring the angle of the lower border of the mandible to the maxilla
how can the face be assessed transversely?
facial symmetry
name a genetic syndrome that can cause a malocclusion?
cleft lip and palate
name the 5 environmental causes of malooclusion
soft tissues- habits- pathology- tumour trauma- intrusion Local factors
name an environmental ST factor
incompetent lips
name a habit that causes malocculsion
thumb sucking
name 5 environmental local factors that can cause malocclusions
supernumerary teeth hypodontia fraenum retained deciduous tooth early loss of deciduous tooth
define mesiodens
supernumerary teeth between the upper central incisors
what problems can mesiodens cause?
prevent other teeth from erupting
define midline diastema and what can cause this
space/gap between maxillary central incisors
can be caused by the fraenum
how can a retained deciduous tooth cause problems?
can prevent permanent tooth erupting into correct position
what is the problem with early loss of deciduous teeth?
loss of space- other teeth may erupt/move into this position disrupting the ‘normal’ eruption process
what does IOTN stand for
index of orthodontic treatment need
what are the 2 components of IOTN
dental health component- severity of treatment need graded 1-5 1=no treatment
aesthetics component- 10 pictures
what is the problem with the aesthetics component
subjective
