week 4 Flashcards
1
Q
how is the maxilla attached to the cranium
A
Numerous sutures
2
Q
maxillary hypoplasia leads to what classification
A
Class III
3
Q
maxillary prognathism leads to what classification
A
Class II
4
Q
a transverse deficiency leads to what classification
A
Posterior crossbite
5
Q
do you need more or less force for orthopedic or orthodontic foces
A
More for orthopedic (500-1000) because distributed over large bone area and bumber of teeth
6
Q
how long do you have to restrain maxillary growth
A
12-16 hours a day (not 6)
7
Q
how is force frequency applied for maxillary growth restraint headgear
A
Intermittend (not cont)
8
Q
what headgear is used to restrain maxillary
A
High pull
cervical pull
Combi
9
Q
what do maxillary protraction face maska and reverse pull headgear attach to
A
Maxillary molars
Ideal: temporary implants and ankylosed teeth
10
Q
when is maxillay protraction face mask and reverse pull headgear
A
10-11 years old for 6-8 months
11
Q
how much change can maxillary protraction-face mask and reverse pull headgear move the skeleton
A
3mm of skeletal movement
12
Q
when is a maxillary transverse deficiency seen
A
Seen in patients with Class III malocclusion
seen in patients with Class II with vertical (long problems)
isolated problems
13
Q
when do you use a palatal expaspander
A
To correct maxillary transverse deficiency
14
Q
what is the target of palatal expansion
A
Midpalatal suture
15
Q
how fast is rapid palatal expansion
A
1mm/day over 2-3 weeks
16
Q
when do you use rapid palatal expansion
A
adolescent patients
17
Q
what type of expanders are used for preadolescent children and preschool for palatal expansion
A
W-arch and Quad helix appliances (not jackscrew-type expanders)
18
Q
how fast is slow expansion
A
1mm/week
19
Q
when is slow expansion done
A
used for late adolescent and young adults
20
Q
what is done after palatal expansion
A
3-6 months of retention for bone consolidation
21
Q
why is it difficult to do RPE in older people
A
Interdigitation (not fusion) of midpalatal suture increases with age
22
Q
what is the comparison between skeletal and dental movement in rapid palatal expansion
A
50% skeletal
50% dental
23
Q
what happens in RPE if the suture is highly interdigitated
A
Production of mostly dental movement
24
Q
how can you do RPE in adults
A
Surgically assisted RPE
25
how does the mandible groe
Mainly at the condyls (endochondral formation)
| posterior and lateral surfaces (intramembrouanous formation)
26
what does mandiblar hypoplasia/retrognathism lead to in classification
Class II
27
what does mandibular prognathism lead to in classification
Class III
28
what does a transverse constriction of the mandible lead to
Brodie bite
29
how can we affect mandibular growth
Functional appliances can accelerate mandibular growth but may not increase the final size of the mandible
30
what is the typical outcome of functional appliances to stimulate mandibular growth
Combined skeletal and dental changes
31
what accounts for the inconsistent skeletal effect of mandibular growth control
loading pattern
32
what negative consequence do functional appliances have on the teeth
Lower incisor proclination
| upper incisor retroclination
33
when would functional appliances not be a good choice
when patient has already proclined lower incisors and retroclined upper incisors
34
why don't we use mandibular growth chin cup headgear
Reduced protrusion by increasing anterior face height rather than shortening size
35
what is the most common treatment for mandibular prognathism
Mandibular surgical setback after cessation of mandibular growth
36
when does the symphysis of the mandible fuse
fuses at 7-8 moths
37
what can mandibular expansion appliances expand
the dento-alveolus, not the basal bone
38
what does expansion of the mandibular base bone require
Surgical procedure via distraction osteogenesis
39
what is distraction osteogenesis
used to lengthen bones via bone fragments gradually opening to create a gap and remodeling
40
what is distraction histogenesis
Adaptation of soft tissues (blood vessels, ligaments, muscles, nerves)
41
what are the 4 major sequential phases of DO
latency
Distraction
Consolidation
Remodeling
42
what is latency
Interval between osteotomy operation and start of distraction
43
what is distraction
Period that distractor activation takes place
44
what is consolidation
Post-distraction period to allow for new bone formation while appliance is still in place
45
what is remodeling
Period that the regenerated bone continues to remodel after appliance removal
46
what is the stability of different symphyseal distractors
Hydrid>tooth borne>bone borne
47
what is the reliablity of transferrring expansion force to bone of different symphyseal distractors
Tooth borne>hybrid
48
what can we change in the skeleton without using surgery
Maxillary protrustion
Hpoplasia and trasverse constriction
mandibular retrognathia
49
can you use growth modification to fix severe skeletal problems
No(must do surgery)
50
what is the soft tissue connecting teeth to the alveolar bone
PDL
51
how big is the PDL
.5mm in width
52
what are the fibers of the PDL
parallel collagenous fibers
53
what are the Cells of the PDL
fibroblasts
Osteoblasts
mesenchmal stem cells
Cells from the vascular structures
54
what strucutres are present in the PDL
Blood vessels and nerve endings (unmyelinated for perception of pain, pressure and position)
55
what is the roll of the tissue fluids in the PDL
viscoelastic elements
| Dampening effects
56
what kind of force does the PDL resist
Short duration forces(act as a shock absorber)
57
what do prolonged forces on the PDL do
Remodel PDL and adjacent bone
58
what is needed to be remodeled for tooth movement
PDL fibers (especially the sharpey's fibers)
59
what does most of the remodeling of the PDL fibers
Fibroblasts already present in the PDL
60
what needs to be done for the tooth to move beyond the PDL Space
Bone resorption
61
what is the roll of the alveolar bone
Support teeth and keep them relatively stable
62
how do osteoclasts resorb bone
Produce acid and enzymes
63
where do osteoclasts come from
Hematopoietic stem cells-> monocytes-> osteoclasts
| (not in PDL need to be recruited from BV or bone marrow)
64
what is the bioelectric theory for tooth movment
Bony chnaged by electrical signals that then chage cell acitivty
65
what is the pressure-tension theory
Pressure and tension alter blood flow causing a release of chem messengers
- chem messenger change cell activities
66
what happens in 1-2 sec after sustained light presssure
Tooth displaced within PDL
67
what happens in 3-5 seconds in sustained light pressure
blood flow changes
68
what happens in minutes of light presssure
Ozygen tension at compression side decreases leading to a release of prostaglandins and cytokines
69
what happens hours after sustained light pressure
Chemical messenger cause metabolic change and second messengers (such as cAMP) release
- osteoclast recruitment (blood flow), maturation and activitation-> frontal bone resorption
70
what happens 2 days after sustained light pressure
Tooth movement beyond the PDL space
71
what happnes in 1-2 sec after heavy pressure
Tooth displaced in PDL space
72
what happens 3-5 sec after heavy pressure
Blood vessels occluded on the Pressure side
73
what happens after minutes of heavy pressure
Blood flow cut off to compressed PDL
74
what happens after hours of heavy pressure
CEll death in compressed area
75
what happens after 3-5 days of heavy compression
Osteoclasts recruitment from bone marrow in the alveolar bone, mature and activate to do undermining bone resorption
76
what happens after 7-14 days of heavy pressure
Tooth movement beyond PDL space
77
where do Osteoclasts come from in light and heavy pressure
Light: blood flow
heavy: bone marrrow in alveolar bone
78
what resorption is done in heavy and light pressure
Light: frontal bone resorption
heavy: undermining bone resorption
79
what kind of force is needed to move tooth
Sustained force is required but continuous is not absolutely necessary
80
how long should you apply force to induce movement
4-8 hours (longer is more efficient
81
what determines the compression/tension regions
Force application pattern
82
what has larger compression area, translation or tipping
Translation`
83
do adults or kids have faster tooth movement
Kids are faster
84
why do kids have faster tooth movement than adults
children have remaining alveolar growth and relatively less dense bone
85
what is the effect of osteopetrosis and osteoporosis on tooth movement in the jaw bones
osteopetrosis slows down tooth movement
| osteoporosis accelerates
86
does the mandible or maxilla move the teeth faster
Maxilla is faster due to less dense bone
87
what drugs can inhibit ortho movement
Prostaglandin inhibitor: NSAID, corticosteroids
| Bisphosphonates
88
what can be done to accelerate tooth movement
Local injury (regional acceleratory phenomenon)
Corticotomy assisted tooth movement (Wilckodontics)
vibration
phottherapy
ultrasound
89
what is the roll of anchorage
Resist unwanted tooth movement and to resist reaction force
90
what is the goal of efficient orthodontics
Maximizing tooth movement and minimize unwanted reactionary effects
91
does incraseing pressure increase tooth movement
Yes, but only to a certain extent
92
what does optimal force depend on
the tooth and the pressure produced at the PDLs
93
what is reciprocal space closure
where two teeth are pulled together with no anchorage
94
how do you do Differential space closure
Use anchorage control using different anchorage values of different teeth
95
what is an anchorage valve
Depends on the root surface
96
what force should be used in differential space closure
Light force
97
what is stationary anchorage control
only allows bodily movement of the molars to pull the anterior teeth forward
98
what is a skeletal anchorage
Uses Temporary anchorage devices(TADs) to prevent unwanted tooth movement
99
how does the pulp react to ortho
Generally is minimal
100
why might the pulp lose vitality
due to previous trauma (ask about pt's dental history)
101
what teeth can be moved ortholy
Proper RCT
102
what teeth should be avoided in major tooth movements
CaOH filled teeth in the anterior with open apices
103
is root remodeling a common theme of ortho
yes. but most people aren't severe
104
where may permanent loss of root surface occur
Primarily at the apex
105
what teeth tend to have root resorption
Incisors and second premolar
106
how common is severe root resorption
1-2%
107
when is root resorption severe
greater than 1/4 root gone
108
what are the risk factors for excessive root resorption
Abnormal root morphology (conical roots, pointed apices, dilacerations)
Prolonged treatment time, excessive and prolonged ortho forces
Genetic predisposition
History of root resorption
109
how much alveolar bone height is loss due to ortho
less than .5mm
110
what happens if perio conserns during treatment
Evaluated/addressed by perio and active disease should be controlled prior
