Skeletal Changes Flashcards
The maxilla is attached to the cranium via what
numerous sutures
What are the three major clinical problems of maxillary growth
maxillary hypoplasia (class III) maxillary prognathism (classII) transverse deficiency (posterior crossbite)
This can be used to restrain maxillary growth
headgear
What is the distribution of forces involving headgear retraining maxillary growth
500-1000g (orthopedic) distributed over large bone areas and number of teeth
What is the force duration involving headgear retraining maxillary growth
12-16 hours/day
What is the force frequency involving headgear retraining maxillary growth
intermittent, not continuous
What are the common headgear variations
high-pull
cervical pull
combination
Where are the intraoral components anchored involving maxillary protraction-face mask and reverse pull headgear
maxillary molars (sometimes premolars)
These can be used for maxillary protraction to minimize unwanted dental movement
temporary implants or ankylosed teeth
When is maxillary protraction-face mask and reverse pull headgear typically done
before the age 9-10 (when sutures close)
How long does maxillary protraction-face mask and reverse pull headgear last
6-8/9-12 months
How much skeletal movement can be achieved involving maxillary protraction-face mask and reverse pull headgear
generally not more than 3mm
In which patients are you likely to see a maxillary transverse deficiency
in patients with class III, class II vertical problems and as an isolated problem
This is a common treatment to correct maxillary transverse deficiency
palatal expansion
This suture is targeted during palatal expansion
midpalatal suture
How much expansion can you achieve with rapid palatal expansion
1mm/day; mostly in adolescents
takes 2-3 weeks
Which is the most common type of palatal expanders
Jackscrew-type expanders
What type of palatal expanders are used in preschool and preadolescent patients
W-arch
Quad helix
1mm/week
3-6 months
This regarding the mid palatal suture increases with age, which increases the difficulty of suture expansion
interdigitation
RPE is mostly done in adolescents and pre-adolescents, which produces what movements
50% skeletal
50% dental
In adults, the mid palatal suture is either fused or highly interdigitated, a palatal expansion would produce what
mostly (if not entirely) dental movements
large movements may require surgically assisted RPE
The mandible grows mainly at which two locations
the condyles (endochondral) posterior and lateral surfaces (intramembraneous)
What are the three common clinical problems of mandibular growth
mandibular hypoplasia/retrognathism (class II) mandibular prognathism (class III) transverse constriction (brodie bite)
Functional appliances can accelerate mandibular growth, but may not what
increase the final size of the mandible
This partly accounts for the inconsistent skeletal effect
the loading pattern
What are the two common unwanted dental effects of functional appliances
lower incisor proclination
upper incisor retroclination
Functional appliances may reduce what, which is acceptable for some patients
overjet
Why is the retraining mandibular growth-chin cup headgear no longer used
it reduces mandibular protrusion primarily by increasing anterior face height rather than shortening its size
This is the most common treatment for mandibular prognathism
mandibular surgical setback after the cessation of mandibular growth
Why is widening of the mandible difficult to achieve
the symphisis fuses at 7-8 months in most humans
Mandibular expansion appliances expand what
dento-alveolus but not basal bone
Expansion of the mandible basal bone requires what
surgical procedure; distraction osteogenesis
This is a surgically and mechanically induced bone regeneration process, which has been used commonly to lengthen limb and craniofacial bones
distraction osteogenesis
How does distraction osteogenesis work
two bone fragments are gradually opened by the distractor to create a gap which induces new bone formation, consolidation, and remodeling
This is a term used to describe the adaptation of the soft tissues which include the blood vessels, ligaments, muscles, and nerves, etc.
distraction histogenesis
This is the interval between osteotomy operation and the start of distraction
latency
This is the period that distractor activation takes place
distraction
This is the post distraction period (appliance is still in place) to allow for new bone formation
consolidation
This is the period that the regenerated bone continues to remodel (after appliance removal)
remodeling
How much should you over-expand so consolidation can occur
30%
