Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Ortho > 3rd year labs > Flashcards

3rd year labs Flashcards

1
Q

appliance design - URA to retract buccally placed 13 and 23 and reduce OB

A

A - 13 and 23 buccal canine retractors, 0.5mm HSSW and 0.5mm ID tubing
R - 16 and 26 Adams clasps 0.7mm HSSW, 11 and 21 Southend clasp 0.7mm HSSW
A
B - self-cure PMMA, FAB OJ plus 3mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

appliance design - URA to correct anterior CB 12

A

A - Z-spring 0.5mm HSSW
R - 16, 26, 14, 24 Adams clasps 0.7mm HSSW
A
B - self cure PMMA, PBP (needs to cover all posterior teeth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

appliance design - URA to retract 13 and 23

A

A - 13 and 23 palatal finger springs and guards 0.5mm HSSW
R - 11 and 21 Southend clasp 0.7mm HSSW, 16 and 26 Adams clasp 0.7mm HSSW
A
B - self-cure PMMA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

appliance design - URA to retract 13 and 23 and reduce OB

A

A - palatal finger springs and guards 13 and 23 0.5mm HSSW
R - 16 and 26 Adams clasps 0.7mm HSSW, 11 and 21 Southend clasp 0.7mm HSSW
A
B - self-cure PMMA, FAB OJ plus 3mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

appliance design - URA to expand the U arch

A

A - midline palatal screw
R - 16, 26, 14, 24 Adams clasps 0.7mm HSSW
A - reciprocal anchorage
B - self-cure PMMA, FPBP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

HSSW gauge for retentive components

A

0.7

adams clasp can use 0.6 for deciduous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

HSSW gauge for stops

A

0.7/(flattened)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

HSSW gauge for active components

A

0.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

HSSW gauge buccal canine retractor (supported)

A

0.5mm sheathed with 0.5mm ID tubing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

HSSW gauge Roberts retractor

A

0.5mm sheathed with 0.5mm ID tubing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

unsupported buccal canine retractor

A

0.7mm HSSW - but too much force so don’t work well - don’t really use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

palatal finger spring - pressure exerted by spring depends on

A

size of coil (3-4mm diameter)
thickness of wire (0.5mm HSSW)
overall length of arm inc coil (approx 20mm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

structure of palatal finger spring in URA

A

active arm engages contact point, applies distal force
guard/guide wire
active arm on top of coil 2/3 into palate/20mm long
3-4mm coil facing mesially
mechanically retained tag embedded within acrylic
waxed out area allowing free movement of spring within acrylic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

action of palatal finger spring

A

can be used to move any tooth M/D along the line of the arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

palatal finger springs to move molars

A

0.8 mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

palatal finger spring - importance of position of coil

A

most important as it influences how efficiently the spring moves the tooth
bisect start finish position for position of coil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

advantages of palatal finger spring

A

provides a light pressure and is well tolerated

several springs can be added if required to retract teeth successively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

disadvantages of palatal finger spring

A

cannot move teeth in a palatal direction so unsuitable for buccally placed teeth
if it was used it may move the tooth further buccally and tend to produce rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

guard wires

A

incorporated to prevent displacement/distortion of the spring during wear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

guard wires position

A

place away from coil and shouldn’t impede tooth movement

usually 0.5mm HSSW with slight curve so it follows the shape of the arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

open spring and guard wires

A

may have guard wire placed on tissue side or either side so in action it slides between the 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

boxed spring and guard wires

A

can have guard wire on tissue side to prevent the spring from becoming distorted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

open palatal finger spring

A

tissues stay much healthier
baseplate of appliance can be much weaker if >1 spring used
easier adjusting as access with the pliers is easier
advisable to use twin guard wires, open springs more liable to distortion if no guard wires used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

boxed/closed palatal finger spring

A

can lead to proliferation of the tissues into the boxed area - not serious problem as only for about 6m
- any temp modification to underlying mucosa quickly reverts to its normal condition after a short time
baseplate much stronger - greater acrylic coverage
acrylic can be used to guide tooth along line of arch
take care to ensure spring over freely within boxed area and has adequate range of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what are wire tags needed for in the baseplate?
mechanical retention
26
ID tubing function
adds strength and rigidity - prevents distortion in buccal sulcus
27
why does a z spring need a lot of retention?
produces a lot of displacement force
28
what are FABPs used for?
correction of an overbite
29
PBP
prop bite open to allow movement of anterior tooth cover all posterior teeth or some will overerupt will go back into position when remove incisors will act as retainer
30
if 7s are PE where should baseplate finish?
behind 6s
31
which teeth will overerupt?
posteriors (incisors don't)
32
Adams clasp - what should you check first?
flyover then arrowhead
33
Adams clasp - if flyover distorts and interferes with occlusion
may not engage into UC if keep biting - metal fatigue - break - could inhale/swallow arrowhead could dig into gingiva - ST trauma
34
midline palatal screw
expands the upper arch
35
midline palatal screw anchorage
reciprocal anchorage
36
what should be used with midline palatal screw?
PBP - if deep occlusal digitation could also pull lower teeth out accidentally too
37
midline palatal screw retention
Adams clasps 4 and 6s - can't use Southend as would split
38
midline palatal screw - if just want to expand posteriors
stop acrylic appropriately
39
midline palatal screw - expand one side more
move division line - larger force on smaller area - will move more
40
midline palatal screw movment
0.2-0.25mm per week turn screw 1-2 per week = 1mm movement per month
41
SS work hardening
hard wire - draw cold metal through a series of dies of successively smaller diameter - causes work hardening - gives wire spring properties further work hardening during bending process of constructing components - utilise to increase spring properties
42
SS wire fractures causes
overworking mechanical abrasion fatigue weld decay
43
overworking
bending then straightening the wire at the same point | creates extreme stresses within the immediate area
44
mechanical abrasion
damaged by burs/stones/crushed
45
fatigue
repeated straining action e.g. continually strained to engage a deep undercut with an Adams clasp
46
weld decay
intergranular corrosion created by overheating alloy causes chromium carbides to ppt at grain boundaries oral fluids can now access the surface of other metals = galvanic action - weakens - fracture
47
18-8 SS composition
``` 72% Fe 18% Cr 8% Ni 1.7% Ti 0.3% C ```
48
Cr in SS
corrosion resistant - forms passive oxide film over surface | lowers temp at which martensite forms
49
Ni in SS
corrosion resistance and strength
50
Ti in SS
prevents ppt of Cr carbides at grain boundaries when alloy heated during welding or soldering
51
18-8 alloy form
austenitic can't be heat hardened and remains soft unless cold worked corrosion resistant when cold worked
52
martensite
principal component of hard steel | formed by quenching from high temps
53
explain why martensite is harder
cube distorted by interstitial carbon atoms that do not have time to diffuse out during quenching - creates crystal defects within the material similar to work hardening - prevent atoms from sliding past one another in an organised fashion - material harder
54
writing a lab prescription
``` cross out missing teeth aim active components retention anchorage baseplate ```
55
active component
whatever applies force to teeth
56
retention
resistance to displacement forces
57
anchorage
resistance to unwanted tooth movement - newtons 3rd law | so only tend to move 1-2 teeth at a time in a URA
58
functions of baseplate
connector retention (cohesion adhesion) anchorage
59
where should the baseplate extend?
halfway to 7s otherwise gag reflex
60
baseplate material
self-cure PMMA - quicker - more residual monomer (allergy) - disposable appliances - properties adequate
61
when should you make the baseplate in heat cure?
if the pt has a known monomer allergy
62
PMMA liquid
monomer
63
PMMA powder
polymer
64
heat cure PMMA advantages
better mechanical properties can control curing - easier to work with more dimensionally stable
65
IO displacement forces
``` gravity mastication tongue talking active component ```
66
tooth movement aim
1mm per month
67
reasons for slow tooth movement
relying on bone resorption and remodelling can cause root resorption/rip PDL can rip/cut off blood supply - necrosis more force = more displacement force
68
increased OJ consequences
trauma risk aesthetics functional - biting
69
avoiding increasing OJ with URA
measure OJ each month - should remain same | baseplate helps to prevent
70
reasons for tx
oral function dental health aesthetics
71
aims of tx
stability function aesthetics
72
what movement do URAs achieve?
tipping
73
advantages of fixed
precise control - rotation and controlled root movement possible multiple tooth movement simultaneously reduced impingement on tongue space can't easily be removed by pt
74
disadvantages of fixed
OH more difficult | components can be ££
75
advantages of removable
no OH problems cheap simple to adjust if correctly manufactured - less clinical time palatal coverage increases anchorage can be adapted to transmit force to blocks of teeth
76
disadvantages of removable
removable only tilting bulky - speech can be initially impaired and can produce increased salivation need careful removal and insertion to avoid fractures or the appliance becoming deformed
77
functional
source of force is not contained in the appliance - most passive constructed so mandible is maintained in a postured position - influences orofacial musculature and dentoalveolar development growing pts
78
advantages of Adams clasp
small, neat, unobtrusive can use on almost any tooth can clasp PE tooth highly versatile - can modify highly retentive provides a site (bridge) where pt can apply pressure with fingertips during removal auxiliary springs can be soldered to bridge can solder hooks or bent in during construction to accept inter-maxillary traction can solder tubes to bridge of clasp to accommodate facebow for EO traction
79
how do teeth move?
prolonged force bone remodelling controlled by PDL - OC and OB around tooth compression and tension areas - causes extra blood flow in both areas increasing cellular activity
80
desirable pressure
25g/sq cm = 1mm per month
81
FABP
OJ+3mm - prevents retroclining L incisors build up of platform of acrylic behind U incisor reduces OB get posterior open bite - will sort as lowers tend to continue erupting remove bite platform then correct OJ
82
stages in appliance delivery
1 - check right appliance and right pt 2 - make sure appliance is the right design 3 - run finger over to ensure no sharp areas 4 - look for potential signs of damage 5 - try in mouth - look for blanching 6 - check posterior retention 7 - check anterior retention 8 - check and activate active components 9 - show pt correct way to insert and remove, get them to demonstrate it back to you 10 - book review 4-6wks
83
advice to give pt
will feel big and bulky, but normal, will get used to it affects speech - lisp - practice reading out loud at home - tongue will adapt lots of saliva - will pass quickly will feel tender/pressure/mild discomfort on that tooth - shows appliance is working wear 24/7 inc mealtimes take it out to clean with soft brush after every meal can take off for contact/active sports = protective container avoid custom gumshields - move teeth back avoid hard and sticky foods - will damage appliance be careful with hot food and drink - baseplate can act as insulator non-compliance will significantly lengthen tx emergency contact details
84
z-spring which coils should be activated?
both coils = for straight movement
85
wire thickness and force
thinner wires - less force

Ortho (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions