ORTHODONTICS Flashcards
What are the four theories of growth control?
- Remodelling theory
- Sutural theory
- Nasal septum theory
- Functional matrix hypothesis
Which of the following is false in the formation of of the orofacial structures inutero?
A) The mandibular processes fuse first
B) The medial nasal processes form the secondary palate
C) The maxillary processes form the upper cheeks
D) The lateral nasal processes fuse last
B) It forms primary palate
Which of the following is true for craniofacial development post-natal?
A) The cranial base grows via intramembranous ossification
B) The maxilla grows via endochondral ossification
C) The mandible grows via intramembranous ossification
D) The cranial vault grows via intramembranous ossifcation
D)
Briefly explain the growth of the maxilla post-natal.
Growth from intramembranous ossification and remodelling
- Intramembranous ossifcation: Frontal and zygomatic sutural growth
- Remodelling: Resorption of the nasal floor and anterior region of maxilla. Apposition on the palate, floor or orbit and tuberosity
Growth = Forward and downwards
What is the age of peak growth velocity for males and females according to heigh charts?
Female = 11-13 (~ early today at around 9-11) Male = 14-16
When should treatment begin for class 2 vs class 3 skeletal issues?
Class 2 = Between CS3 and CS4 (peak growth velocity)
Class 3 = Before CS3 (prior to peak growth velocity)
What is the leeway space for maxilla and mandible?
Maxilla = 1.5mm/quadrant Mandible = 2.5mm/quadrant
What landmarks are used for overall convexity and explain the skeletal class related to concave and convexed facial profile.
Landmarks = Glabella, subnasale and soft tissue pogonia
Convex = Class 2 Concave = Class 3
Explain the mandibular plane angle in relation to the frankfort plane for:
- Normal
- Skeletal deep bite (class 2)
- Skeletal openbite (class 3)
Normal = Meets behind the head Skeletal deep bite (class 2) = Flat angle, never meet Skeletal openbite (class 3) = Steep angle, Meet just posterior to the ear
Name 6 ways to create space in crowded occlusion.
SPEEDL S - Stripping P - Proclination E - Expand E - Extract D - Distalisation L - Leeway space
How to calculate space deficiency/excess in mixed dentition?
Space available:
Measure the arch length OR contour piece of wire on cast, straighten out and then measure with ruler
Space required:
- Measure incisors (4 teeth)
- Estimate the width of 3, 4 and 5 using radiograph technique or tables
- Leeway space
- Curve of spee (COS per quadrant added together, divide by two and + 0.5)
What changes to the facial structure/occlusion occur in mouth breathing?
- Narrow maxillary arch = Posterior crossbite
2. Lowered mandible and tongue position = Eruption of posterior teeth, increased facial height and overjet
What are the four D’s of force
- Direction
- Degree
- Distribution
- Duration
Which of the following is the correct treatment for the jaw discrepancies? A) Skeletal class 2 with maxillary prognathic - functional appliances B) Skeletal class 2 with mandibular retrognathic - reverse headgear C) Skeletal class 3 with maxillary retrognathic - reverse headgear D) Skeletal class 3 with mandibular prognathic - functional appliances
C)
What are the two functional appliances available to treat mandibular retrognathia?
o Twin block = Removable appliance
Mandible bought down and forwards
• Condylar growth
• Glenoid fossa remodeling
Maxillary growth inhibition
Distal pressure applied on maxillary teeth (when mandible attempts to return to normal position)
Forward pressure applied on mandibular teeth
o Herbst = Fixed appliance
Activation of mandible forwards by arms
Patient able to open/close and lateral movements
