Ortho Flashcards
99% of people have normal occlusion
True or false
False 30-40%
What do you need to tell patients who have an increased overjet who opt not to have ortho
Increased risk of trauma
What are the main issues with impacted teeth (non third molar)
- Cause root root resorption of adjacent teeth
- Cysts associated with them may also cause resorption
- May prevent eruption of adjacent teeth (supernumerary)
What Angle Classification is this:
Mesiobuccal cusp of the upper 6, occludes with the mesiobuccal groove of the lower 6
Class I
What Angles Classification is this?
Mesiobuccal cusp of the upper 6 occludes mesial to the mesiobuccal groove of the lower 6
Class II
What Angles classification is this?
Mesiobuccal cusp of the upper 6 occludes distal to the mesiobuccal groove of the lower 6
Class III
What BSI classification is this?
Lower incisor edges occlude with or lie immediately below the cingulum plateau of the upper centrals
Class I
What BSI classification is this?
Lower incisor edges lie posterior to the cingulum plateau of the upper incisors. Upper 1s are proclined or of an average inclination. Increased overjet.
Class II, Div I
What BSI classification is this?
Lower incisor edges lie posterior to the cingulum plateau of the upper incisors. Upper 1s are retroclined. Usually minimal overjet or may be increased.
Class II, Div II
What BSI classification is this?
Lower incisor edges lie anterior to the cingulum plateau of the upper incisors. Reduced or revered overjet.
Class III
What canine classification is this?
Maxillary permanent canine occludes directly in the embrasure between the mandibular permanent canine and first premolar
Class I
What canine classification is this?
Maxillary permanent canine occludes mesial to the embrasure between the mandibular permanent canine and first premolar
Class II canine
What canine classificaiton is this?
Maxillary permanent canine occludes distal to the embrasure between mandibular permanent canine and first premolar
Class III
Describe a Class I skeletal pattern
Mandible is 2-3mm posterior to the maxilla
describe a class II skeletal pattern
Mandible is retruded relative to maxilla
Describe a class III skeletal pattern
Mandible is protruded relative to the maxilla
Three commonly used indexs for quantitative measure of impacts of malocclusion
- IOTN
- PAR
- ICON
Ideally individuals should have routine oral screening by a GDP from what age
9-10
What is the key indicator for lip incompetency
Muscle contraction visible when patient asked to close lips together.
what is the line from the soft tissue chin to the tip of the nose called?
Ricketts Esthetic Plane or E-line
In an ideal situation, the lower lip is how far form the Rickets E line?
How far is the upper lip?
Lower lip 0 to 2mm posterior to line
Upper lip, slightly further posteriorly
What is assessment of Rickets E plane useful for?
Detecting excessive incisor protrusion
What is the angle of the mandibular plane called
Frankfort mandibular plane angle (FMPA)
Smile lines are usualy 1-2mm higher in females
True or false
True
In an ideal smie, the whoe height of the upper incisor is visible, with only interproximal papillae visible.
true or false
true
What is a consonant smile arc?
Where the upper incisor edges are parallel to the lower lip
In addition to 8s and upper 2s, what other teeth are often congenitally missing
5s
What teeth are most likely to erupt ectopically
6s and upper 3s
What should you do to quantify the space required in each arch for correction of a malocclusion
Space analysis
Space is required in order to correct (6)
- Crowding
- Obtain a normal overjet
- Level occlusal curves
- Arch contraction
- Upper incisor tip
- Upper incisor torque
Mild crowding is less thanmm space needed
4
Moderate crowding is there there is mm space needed
4-8mm
Severe crowding is where there is greater than mm space needed.
8mm
What teeth do you measure in permanent tooth space analysis
Mesial 6 to mesial 6
Spontaneous correction of mild crowding is possible at what age
7-9
Extractons are always required for correction of moderate crowding
True or false
False. Often can treat non-extraction with fixed appliances
As a general rule it is better to leave any ortho extractions until:
Early permanent dentition
At what age do kids usually have a full set of permanent teeth?
12 or 13
For every minimeter of incisor retraction, how much space is needed?
-2mm
For every millimeter of incisor proclination how much space is needed in arch
+2mm
The antero-posterior occlusal curve is called:
Curve of spee
Space is needed to level a curve of spee
True or false
True
List 6 methods of space creation/use
- Extraction
- Molar distal change
- Molar mesial change
- Expansion
- tooth reduction/enlargement
- Space opening
How are molars able to be distalised to create space
- Headgear or fixed intra-oral appliacnes
- Best done before 7s erupt
- Best for upper 6s
What is molar mesialisation for space creation?
Use a space maintainer to maintain leeway space.
How much leeway space in maxilla
0.9-1.5mm per side
How much leeway space in the mandible
1.7-2.5mm (per side)
Up to ……mm can be removed from the mesial and distal aspect of teeth to create space
0.25mm
Effect of early loss of A primary tooth:
Little effect on dentition
Effect of early loss of Bs on the dentition:
Little effect
Effect of early loss of C’s on dentition:
Affect centrelines, not buccal segments
Effect of early loss of D’s on the dentition
Can affect midline AND buccal segments
Effects of early loss of Es on dentition
Affect buccal segments, but not midlines
What is the ideal arch form?
Parabola
It is important to try and conserve the basic arch form of the patient.
True or false
True, particularly lower arch
What is Bolton Analysis used to measure?
Tooth size discrepancy
A TSD below mm is clinically insignificant
1.5mm
4 ways to address tooth size discrpancy:
- Extraction in arch with excess
- interproximal stripping
- Angle teeth to occupy smaller or larger space
- Increase width with resin etc
TSD is intra-arch analysis
True or false
FALSE. it is inter-arch analysis
Space analysis is intra-arch.
From tooth 3-3 a proportional TSD is:
77.2% +/- -.22
(if greater than 77.2% = mn excess, is less, max excess)
What is the % used for bolton analysis of all teeth(as opposed to just 3-3)
91.3% +/- 0.26
What plane does a Lat Ceph not assess
Transverse - need Posterio-anterior cephalomatric x-ray
Lat Cephs are used to assess
a) vertical features
b) Anterior-posterior features
c) Transverse features
A and B
How much is the radiation dose from an OPG
54uSv
How much is the radiation dose from a full mouth series of x-rays
150uSv