Orthodontics Flashcards
1
Q
BSI definition of class 2 div 1
A
lower incisor edges lie posterior to the cingulum plateau of the upper incisors
increased overjet
the upper centrals are proclined or of average inclination
2
Q
how common is class 2 div 1 malocclusion
A
15-20%
3
Q
why do you treat class 2 div 1
A
aesthetic concerns
dental health (trauma)
4
Q
skeletal pattern associated with class 2 div 1
A
retrognathic mandible
class 2 AP
5
Q
what is the overjet in class 2 div 1 caused by
A
skeletal pattern
tooth inclination
combination
6
Q
what is SNA
A
relation of maxilla to pituitary fossa
7
Q
what is SNB
A
relation of mandible to pituitary fossa
8
Q
if the ANB is smaller than normal values what does this suggest
A
class 3 (prognathic mandible/retrognathic maxilla)
9
Q
if the ANB is bigger than normal values what does this suggest
A
class 2 (prognathic maxilla/retrognathic mandible)
10
Q
normal values for SNA
A
81 +/- 3
11
Q
normal values for SNB
A
78 +/- 3
12
Q
normal values for ANB
A
3 +/- 2
13
Q
what is the normal proclination of upper incisors
A
109 +/- 6
14
Q
what is the normal inclination of lower incisors
A
93 +/- 6
15
Q
soft tissue pattern associated with class 2 div 1
A
incompetent lips
lower lip trap
16
Q
dental factors of class 2 div 1 malocclusion
A
increased overjet
overbite varies
various spacing/crowding patterns
class 2 molars
dry gingiva and gingivitis
17
Q
occlusal features of a sucking habit
A
proclination of upper anteriors
retroclination of lower anteriors
localised AOB or incomplete OB
narrow upper arch
18
Q
what are the principles of treating a habit
A
reinforcement
removable appliance habit breaker
fixed appliance habit breaker
19
Q
management options for class 2 div 1
A
accept
growth modification
URA
camouflage
orthognathic surgery
20
Q
when would you accept a class 2 div 1
A
mildly increased overjet
big overjet but not unhappy
21
Q
what does a functional appliance do
A
utilise, eliminate or guide the forces of muscle function, tooth eruption and growth to correct a malocclusion
22
Q
what way is the mandible postured with a class 2 div 1 when wearing a functional appliance
A
downwards and forwards
23
Q
what functional appliance is used for class 2 div 1
A
twin block
24
Q
what are the therapeutic effects of a functional appliance for class 2 div 1
A
distal movement of uppers
mesial movement of lowers
retroclination of upper incisors
proclination of lower incisors
25
advantages of using functional appliance in early phase of treatment for class 2 div 1
improve appearance earlier
reduce risk of trauma
better compliance
26
disadvantages of using functional appliance in early phase of treatment for class 2 div 1
early skeletal changes not maintained
treatment time increased
little difference in long term effects
27
active component in retroclining anterior teeth
roberts retractor 0.5mm in tubing
28
retention for URA (posterior)
adams clasps on 6s
0.7mm HSSW
29
baseplate requirements for URA to retrocline anterior upper teeth
flat anterior biteplane (overjet +3mm)
30
what does ARAB stand for
active component
retention
anchorage
baseplate
31
BSI definition of class 3 malocclusion
lower incisor edge occludes anterior to the cingulum plateau of the upper central incisor
overjet is reduced or reversed
32
incidence of class 3 malocclusion
3-7%
33
skeletal factors of class 3 malocclusion
class 3 AP
small maxilla/large mandible
retrusive maxilla sites on wider parts of the mandible causing bilateral crossbites
34
dental features of class 3 malocclusion
class 3 incisors and molars
reverse overjet
reduced overbite
AOB
crossbites
crowded maxilla, spaced mandible
proclined upper incisors and retroclined lowers (compensation)
displacement of closing
35
what part does the soft tissues have to play in the dentoalveolar compensation of a class 3
tongue proclines upper incisors
lower lip retroclines lower incisors
36
why do you treat a class 3
aesthetics
dental health - attrition and recession
speech and mastication
37
what factors make a class 3 more difficult to treat
> number of teeth in anterior crossbite
skeletal element in aetiology
> AP discrepancy
presence of AOB
unfavourable facial growth
38
when would you accept and monitor a class 3
no concerns
no dental health indications
mild cases
39
what would a URA aim to do for a class 3
procline incisors over the bite
40
what functional appliances are used for a class 3
chin cup
reverse twin block
frankel 3
protraction headgear and rapid maxillary expansion
41
what factors are favourable when trying to camouflage a class 3
growth has stopped
mild to moderate class 3 skeletal base
average/increased overbite
can reach edge to edge
little to no dentoalveolar compensation
42
what extractions are used for class 3 camouflage
upper 5s
lower 4s
43
how long does combined orthodontic and orthognathic treatment take
pre-op ortho is 18 months
surgery
post-op ortho 6 months
44
BSI definition of class 2 div 2
lower incisor occludes posterior to the cingulum plateau of the upper incisor
upper incisors are retroclined
overjet is reduced but can also be increased
45
skeletal pattern of class 2 div 2
AP 2
reduced FMPA
prominent chin
46
soft tissue features of class 2 div 2
high resting lower lip line
marked labio-mental fold
high masseteric forces
lower lip trap sometimes with upper 2s
47
dental features of class 2 div 2
retroclination of upper centrals
upper 2s crowded and mesio-labially rotated
deep overbite
OJ reduced
class 2 molars
increased inter-incisal angle
48
why treat class 2 div 2
aesthetics
traumatic overbite
49
functional appliance for class 2 div 2
modified twin block
50
what are the main headings in a patient assessment appointment when taking history
CO
MH
DH
trauma history
habits
SH
51
occlusal features of a digit sucking habit
proclination of upper anteriors
retroclination of lower anteriors
localised AOB or incomplete OB
narrow upper arch and unilateral posterior crossbite
52
what do you look at in the extra-oral ortho patient assessment
AP class
LAFH/FMPA
symmetry
competent lips
lip trap
naso-labial angle
smile line
TMJ
53
how do we assess AP class
visual assessment
palpate skeletal bases
lateral cephalometry
54
what is included in the intra oral ortho patient assessment
erupted teeth
hygiene and poor prognosis
perio and wear
degree of crowding
incisor inclination
incisor class
overjet
overbite
centre lines
molar class
canine class
crossbite
mandibular displacement
55
what would make a tooth poor prognosis
grossly carious
heavily restored
significant trauma
significant hypoplasia
56
how many millimetres for mild, moderate, severe crowding
mild = <4mm
moderate = 4-8mm
severe = >8mm
57
assessment methods for crowding
space available/space required
overlap technique
mixed dentition analysis
58
diagnostic records used in ortho assessment
radiographs
study models
photographs
sensibility tests
CBCT
59
what radiographs are commonly used in ortho
OPT
upper anterior occlusal
lateral cephalogram
60
what is the presentation of hypodontia
delayed or asymmetric eruption
retained or infra-occluded deciduous teeth
absent deciduous tooth
tooth form
61
advantages of a resin bonded bridge for hypodontia cases
simple
can do when young
non-destructive
can look good
place on semi-permanent basis
62
disadvantages of a resin bonded bridge for hypodontia cases
failure rate
appearance sometimes not good
orthodontic retention needs are high
63
what are the properties of fixed appliances
3D control
complex tooth movements
control of root
less dependent on compliance
need good oral hygiene
risk of iatrogenic damage
poor intrinsic anchorage
64
what are the properties of a URA
simple tooth tipping
no control over root
greater compliance required
less risk of iatrogenic damage
good intrinsic anchorage
can be lost
65
when are fixed appliances used
correct of mild to moderate skeletal discrepancies
alignment
rotations
centreline correction
overbite and overjet reduction
closure of spaces/creating spaces
vertical movements of teeth
66
components of fixed appliances
bracket/tube
band
archwire
modules
auxiliaries
anchorage components
force generating components
67
how do you bond brackets to teeth
acid etch and composite resin
68
how do you bond orthodontic bands to teeth
glass ionomer
69
properties of nickel titanium as archwire
flexible
light continuous force
shape memory
higher friction than stainless steel
70
force generating components in orthodontics
elastic power chain
NiTi coils
intra-oral elastics
active ligature
71
dental features with high orthodontic relapse potential
diastema
rotations
palatally ectopic canines
proclination of lower incisors
anterior open bite
instanding upper lateral incisors
72
what are the risks of fixed appliances
decalcification
root resorption
relapse
73
how do you fix a fractured southend clasp
trim baseplate end so flush with plate, make single C clasp and fold over so not sharp
74
how do you fix when an adams clasp is completely fractured off
smooth down sharp areas where it comes from if still retentive
send to lab with original working cast or take new imp with URA in mouth (to prevent acrylic creep)
75
what do you do if a bracket has debonded and can rotate
take ligature off and then take bracket off and send to orthodontist
76
what happens if a fixed bonded retainer has debonded from 4 out of 6 teeth
take it all off and check lingual surfaces for caries and send to orthodontist/offer vacuum formed retainer
77
what do you do if a transpalatal arch has fractured from the metal band
thread floss through the arch and get the patient to hold this and remove arch by cutting at band with bur
or remove the bands from the teeth and snip the arch wire
78
what to do when adams clasp is fractured at the arrowhead
cut it at the baseplate to remove a flyover and cut the bridge so only one arrowhead left and then fold it up so it is safe
79
what do you do if archwire has slipped
secure excess wire with tweezers, cut and bend into retentive tag on both sides
80
what are the benefits in orthodontic treatment
appearance
function
dental health
81
what does MOCDO stand for
missing teeth
overjet
crossbites
displacement of contacts
overbites
82
how do you assess the IOTN health component
MOCDO
83
issues with anterior crossbites
loss of perio support
tooth wear
84
what may a significant displacement in a posterior crossbite lead to
asymmetry
early correction
85
what can a deep traumatic overbite cause
gingival stripping
loss of perio support
86
problem with overjet
upper incisor trauma
87
problem with missing/ectopic teeth
root resorption
cyst formation
88
how to prevent decalcification in orthodontics
case selection (good OH, motivated patient)
oral hygiene
diet advice
fluoride
89
what indicates a high risk of decalcification
pre-existing decalcification
erosion
caries history
90
what must orthodontic oral hygiene include
brushing minimum twice a day thoroughly
brush after every meal
use of disclosing tablets
interdental brushes
single tufted brushes around each bracket
91
what is the average root resorption over 2 years use of fixed appliances
1mm
92
what teeth suffer from root resorption due to orthodontics the most
upper incisors
93
risk factors for root resorption
type of movement (prolonged high force, intrusion, large movements, torque)
root form (blunt, pipette, resorbed)
previous trauma
nail biting?
94
types of removable retainers
pressure/vacuum formed
essix
hawley
95
what does the dental health component of the IOTN record
various occlusal traits of a malocclusion that would increase the morbidity of the dentition and the surrounding structures
96
what is an active component
component that will be moving teeth with application of force
97
what is retention in orthodontics
resistance to displacement forces
98
what is anchorage
resistance to unwanted tooth movement
99
what does the baseplate do
connects all components
provides anchorage
assists with retention
100
what active component retracts canines to a more distal position
palatal finger springs and guards 0.5mm HSSW
101
what is used to reduce an overbite
flat anterior bite plane
102
advantages of URA
tipping of teeth
good anchorage
cheaper
shorter chairside time
oral hygiene easier to maintain
non-destructive
GDP can do it
easily adapted for overbite reduction
achieve block movements
103
disadvantages of a URA
less precise control of tooth movement
easily removed by patient
1-2 teeth at a time
technicians needed for construction
rotations hard to correct
104
how does the adams clasp work
uses mesial and distal undercuts of the buccal aspect of teeth to fit into to grip the tooth so that displacement of appliance is resisted
105
what are the gauges of wire for retentive components
0.7mm HSSW
106
what are the gauges of wire for active components
0.5mm HSSW
107
what active components require tubing and what is the gauge of this tubing
buccally placed active components:
- buccal canine retractor
- roberts retractor
0.5mm internal diameter tubing
108
what are the 10 things you do when fitting a URA
ensure patient details match appliance
check appliance matches design
check for sharp areas
check integrity of wirework
insert appliance into mouth and look for blanching or soft tissue trauma
check posterior retention
check anterior retention
activate appliance
demonstrate insertion and removal of appliance
book review in 4-6 weeks
109
what component retracts buccally placed canines
buccal canine retractor 0.5mm HSSW 0.5mm ID tubing
110
what are the 10 patient instructions once they have received their URA
will feel bulky
cause initial salivation (pass in 24hrs)
impinge speech for short time (read book)
can cause initial ache (indicates it is working)
to be worn 24/7
remove after every meal and clean with soft brush
remove when contact or active sports
avoid hard or sticky foods
missing appointments and non-compliance will lengthen treatment time
provide emergency contact details in case any problems
111
what active component pushes a tooth out of a crossbite
Z spring 0.5mm HSSW
112
if you are correcting an anterior crossbite on a URA, what addition will you need to the baseplate
posterior bite plane
113
what 10 things do you check for when checking that an adams clasp is engaged and active
arrowheads engage mesial and distal undercuts
bridge of clasp stands clear of tooth at 45 degrees to crown
arrowheads parallel
arrowheads 45 degrees to tooth surface
arrowheads not touching adjoining teeth
bridge not protruding above occlusal surface
flyover fits closely over contact areas
clearance of 0.5-1mm between wire and tissue in palate
tags present at ends of wire for mechanical retention
gingival margin only trimmed if tooth not fully erupted
114
when prescribing a roberts retractor to retract 4 incisors, what must you also remember to put on the lab card
mesial stops on the canines 0.7mm HSSW
115
what active component expands the upper arch
midline palatal screw
116
if you are using a midline palatal screw what is the anchorage
reciprocal anchorage
117
if you are expanding the upper arch what do you need to add to the baseplate
posterior bite plane
118
when does primary eruption begin and end
6 months - 2.5 years
119
what is the order of eruption of primary teeth
abdce
lowers before uppers
120
when would you choose to extract neo-natal teeth
when mobile and presenting inhalation risk
if causing difficulty with breastfeeding
121
order of eruption of permanent teeth and at what ages
6s - 6
1s - 7
2s - 8
4s - 10
3s and 5s - 11-12
7s - 12-13
122
what are the main reasons for lateral cephalograms
look at severity of underlying skeletal pattern
confirm incisor relationship
unerupted tooth
123
what radiographs are used for maxillary unerupted teeth
OPT and anterior occlusal
or 2 PAs
124
how do you check for the presence of unerupted permanent canines
palpate buccally and palatally
check mobility of c's
angulation of adjacent lateral incisors
mobility of lateral
colour change in lateral
125
what is the aetiology of unerupted canines
long path of eruption
genetics with peg laterals/hypodontia
class 2 div 2
crowding
ectopic position of tooth germ
126
treatment options for ectopic canines
accept
extract c
bonding gold chain
open exposure
surgically remove
autotransplant
127
what factors of the position of an unerupted canine on a radiograph would look favourable for eruption
distal to the midline of the lateral
not too horizontal
not too high
128
what are the risks of leaving an ectopic canine unerupted
root resorption of adjacent teeth
ankylosis of canine
risk of cyst formation
make restorative hard
resorbed canine crown
129
when would you opt to surgically remove an ectopic canine
if unable to get good path of movement into arch
early damage to root of lateral
patient doesnt want to wear a brace
patient crowded and 2-4 has nice contact
130
consequences of accepting position of an unerupted maxillary incisor
ankylosis
root resorption
drift of lateral
cyst formation
131
how do you manage unerupted central incisors
make space if patient less than 9yrs and wait 6-12 months
132
what is the aetiology of unerupted central incisors
trauma to deciduous incisors
supernumerary (tuberculate)
retained primary tooth
early loss of primary
crowding
ectopic position of tooth germ
133
systemic reasons for delayed eruption
downs
cleidocranial dysostosis
cleft lip and palate
hereditary gingival fibromatosis
turner syndrome
rickets
134
what would an AOB and unilateral crossbite together indicate
digit sucking habit
135
causes of an anterior open bite
tongue thrust
thumb sucking
skeletal position
upper and lower incisors only partly erupted
136
why do we not compensate if we are taking an upper 6 out
because if you time it right the upper 7 will move quickly into the 6s position so no need
137
what would you do if infraocclusion of primary tooth and permanent tooth is present and unerupted
extract and space maintenance
138
what would you do if infraocclusion of primary tooth and permanent tooth not present
refer as hypodontia case
either close space or make prosthetic
139
why does infraocclusion occur
ankylosis of the tooth then rest of alveolar bone and teeth develop and erupt around it
140
what 3 traumatic things can happen with an anterior crossbite
displacement on closing
gingival recession
mobility
141
aetiology of a midline diastema
hypodontia
generalised spacing
low hanging fraenum
laterals impinging on central roots
unerupted supernumerary
142
incidence of decalcification
73%
143
post orthodontic treatment of decalcification lesions
natural remineralisation
CPP-ACP
microabrasion
resin infiltration
144
who is more likely to get recession from ortho treatment
thin biotypes
non-extraction and orthognathic patients
145
how to treat recession patients after ortho
sensodyne toothpaste
gingival grafting
