ortho 5 zoom notes Flashcards

1
Q

how would you reduce a 6mm OJ 22, 21, 11 and 12 and reduce the OB
ie do the appliance design

A

extract 1st premolars

aim: please construct a URA to reduce (OJ) 22, 21, 11 + 12 ~ reduce OB

Active Component: 22, 21, 11, 12; Roberts retractor; 0.5mm HSSW + 0.5mm I.D. tubing

stops: 13 + 23; medial stops; 0.7mm (flattened) HSSW
retentive: 16+ 26; Adams clasps; 0.7mm HSSW
anchorage: moving 4 teeth (yes and no)
baseplate: self-cure PMMA, flat anterior bite-plane (FABP); overjet + 3mm

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2
Q

why would you expand the upper arch

A

crowding

posterior cross bite

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3
Q

what is the active component when expanding the upper arch

A

midline palatal screw

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4
Q

what sort of retention can we use when we want to expand the upper arch

A

Cannot use a southend clasp as it would inhibit expansion by holding the teeth together

A labial bow also has the potential to inhibit this expansion (could also potentially cause the arch to flatten) ~ not impossible but not the best

Adam’s clasps for posterior and anterior retention are the best choice (utilise the molars and premolars)

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5
Q

if you are expanding the upper arch and the patient needed retention on deciduous teeth which thickness of wire would we use

A

0.6mm

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6
Q

what sort of anchorage do we have when expanding the arch

A

reciprocal anchorage
ie what happens on one side the same thing will happen on the other side (Newton’s 3rd law)
= expansion on one side happens the same on the other side

we are using the face that we don’t have anchorage to expand the upper arch

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7
Q

what is different about the appliance to expand the arch

A

Get a saw and cut appliance exactly down the middle to the screw
Only component holding 2 sides together is the screw

Give patient a little key to activate it themselves once or twice a week

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8
Q

how much tooth movement do we normally want per month

A

Usually we want 1mm tooth movement per month

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9
Q

when the patient activates their appliance how much movement do we want per week

A

If we get patient to activate it themselves we are looking at 0.2-0.25mm per week

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10
Q

what is added to the base plate if the patient has a posterior cross bite

A

posterior bite plane

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11
Q

what happens if we only want to expand the upper left posterior quadrant

A

We can change where we do our cut on the appliance

Based on newtons law
Only moving 4 teeth (segmental movement)
So there is considerably less movement on the other teeth
Greater subject of force on 4 teeth and the rest of the force is spread over more teeth
Get 4mm to the left and maybe 1mm in the other direction

Dissipating the force
Kind of like tug of war
More force on one side than the other then it will go to the side with more force

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12
Q

How can we move posterior teeth and not the anterior teeth?

A

Just don’t include anterior teeth and get your base plate to finish before anterior teeth

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13
Q

what is bi-expansion

A

= equal expansion on both sides

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14
Q

what do we need to include on the bite plate if we only want to move one side and why

A

If we only want to move one side then we need to include the anteriors to get greater anchorage force

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15
Q

what are % of elements in satin steel

A

0.3% carbon

72% iron

18% chromium

1.7% titanium

8% Nickle

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16
Q

what are the advantages of URA

A
  • excellent anchorage
  • easy to clean
  • cheaper than fixed
  • can produce tipping / tilting movement
  • block movements of teeth
  • non-destructive to tooth surfaces
  • minimal special training
  • shorter chair side time
  • good for reducing overbite
17
Q

what are disadvantages of URA

A
  • Less precise tooth movement
  • need patient compliance
  • cannot easily rotate teeth
  • can only move 1-2 teeth
  • need lab to make
18
Q

what is the thickness of Adam’s clasps for permanent teeth

A

0.7mm

19
Q

what is the thickness of Adam’s clasps for deciduous teeth

A

0.6mm

20
Q

what does uncoiling a palatal finger spring do

A

activates the component

makes the tooth move back

21
Q

what happens when you activate both coils of a z-spring equally

A

pushes tooth straight forwards

22
Q

what happens when you only activate one coil of a finger spring

A

one side moves forwards