Ortho Flashcards
How do you examine a person’s growth stage?
Using their C2-4 vertabrae
What is the best timing for class II treatment?
Class II is best treated with inclusion of peak mandibular growth which is the end of CS2 and the begining of CS3
What is the best timing for class III treatment?
Class III is best treated with maxillary expansion and protration and is only effective before peak growth which is during CS1 and CS2
In considering growth and development, an understanding of the concepts of pattern, variability and timing is important. What is your understanding of each of these terms?
Predictability - is the common incidence of an event
Variability - a spectrum of an incidence
Timing - same events may happen at different times
What is a malocclusion?
Malocclusion is a failure of the dento-alveolar compensatory mechanism. Tooth position post-eruption is influences by ST and oro-facial function (habits)
What are the reasons for crowding?
Primary crowding - result of smaller jaws
Secondary - result of early exfoliation of the deciduous tooth thus permanent erupts in a different postion
What is the length of a dental arch?
Antero-posterior distance from CI to the most distal point of the 2nd primary molars
What is the arch circumference?
Distance measured aroudn the arch from the mesial contact of the 1st permanent molars to the contralateral mesial contact of the 1st permanent molar
What is inter-canine width?
Horizontal distance between the cusp tips of the upper canines or the lower canines
How do permenent incisors fit into the arch?
Increased space requirments gained from:
- Residual spacing between deciduous incisors
- Permanent incisors erupt lingual originally and move more labially
- Deciduous canine move distally as insisors erupt
- Transverse increase in the intercanine arch width
Usually, distema between central incisors close but when do they persisst?
- Decidou canine has been lost
- Upper incisors are proclined
- High frenum attachment
To fix:
1. Wait for canine to erupt
2. Attempt ortho
3. Frenectomy might be needed
How do you determine skeletal class according to AP skeletal classification?
You need to draw the line between ST glabella - Subnasale - ST Pogonian
Class I: Mx 2-4 mm anterior to the mandible
Class II: Md retrusive to Mx - ST Pogonian is posterior tot he line
Class III: Md protrusive relative to Mx ST pogonian anterior tot eh vertical line
What are the angle molar classes?
Always need the first permanent molars for this .
Class I - Mesio-buccal cusp of the upper molar coincdes with the buccal groove of the lower molar
Class II - Is anterior to the buccal grove and can be shifted forward by 1/4, 1/2, 3/4 or full unit (full unit = size of a premolar)
Class III - Is posterior to the buccal groove and can be shifted backward by 1/4, 1/2, 3/4 or full unit (full unit = size of a premolar)
What is the definition of the Class I incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Class I is when lower central edges occlude with or lie immediately below the cingulum plateau of the upper central
What is the definition of the Class II incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Class 2 Lower central edges occlude posterior to the cingulum plateau of the upper central
Div 1 - increase OJ is observed due to upper central incisor proclination
Div 2 - Increase or minimal OJ and upper central incisor is retroclined
What is the definition of the Class III incisor relationship?
It is a relationship of the mx and md incisors which represents a truer reflection of the underlying skeletal base relationship and what is often of most concern to the pt.
Lower central edges occlude anterior to the cingulum plateau of the upper central incisor. OJ is reduced or edge to edge.
What is tipping?
Apex is in normal position but crown is incorrectly positioned
What is displaced teeth?
Both apex and crown are incorrectly positioned
What is rotated teeth?
It is when teeth are rotated along the long axis