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BDS3 Ortho Lab > Mr Nairn's tutorials > Flashcards

Mr Nairn's tutorials Flashcards

1
Q

what is the index of orthodontic treatment need

A
  • ranks malocclusion in terms of the significance of various occlusal traits for an individual’s health and perceived aesthetic impairment
  • two components
    • aesthetic component
    • dental health component
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2
Q

what is this

A

Adams 64 pliers

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3
Q

what is this

A

Coil formers 65

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4
Q

what is this

A

wire cutters

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5
Q

what wire do we use in ortho

A

hard stainless steel

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6
Q

what is bending

A

rigid

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7
Q

what is manipulation

A

slowly following the curve

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8
Q

Problems with an overjet

A
  • trauma
  • aesthetic
  • incompetant lips
  • potential lip trap
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9
Q

What is the acronym used for designing URAs

A

ARAB

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10
Q

What does ARAB stand for

A

A: active component/s

R: retentive

A: anchorage

B: baseplate

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11
Q

What do we say for the active component

A
  • component that will move the teeth through the application of force
  • gauge of wire
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12
Q

what is the retentive component

A
  • resistance to displacement forces
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13
Q

examples of retentive elements

A
  • Adam’s clasps
  • southend clasp
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14
Q

what are the 5 main displacement forces of a URA

A
  • tongue
  • gravity
  • mastication
  • talking
  • the active component
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15
Q

What is anchorage

A

the resistance to unwanted tooth movement

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16
Q

3 functions of a base plate

A
  • holds all components together
  • helps with retention
  • helps with anchorage
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17
Q

advantages of heat cure over self cure PMMA

A
  • can control when it cures
  • better polymerisation (all free monomer is used up, very little chance of allergic reaction)
  • less shrinkage with heat cure
  • stronger
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18
Q

disadvantage of heat cure PMMA

A

takes ages

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19
Q

so what is better, heat cure or self cure PMMA

A

heat cure is better but self care is satisfactory and a lot faster

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20
Q

what is the problem with anchorage

A

newton’s 3rd law

  • for every force there is an opposite and equal reaction
    e. g. 6mm OJ, over 6 months, the gap should become zero

Gives a gap of 6mm between lateral and canine. The canine has moved 6mm distally ?? But based on newtons 3rd law, if they cannot move, instead of canines moving back, everything else has moved forward. Forces have gone into the baseplate instead of the canines and everything else moves forward. This is a disaster and why anchorage is a nightmare becauses the overjet will now be 12mm. If you do this, contact indemnity.

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21
Q

how do you prevent having problems with anchorage

A
  • aim for 1mm of tooth movement per month
  • on every visit
    • measure the gap (monthly basis)
    • measure the overjet (if the appliance is working the overjet shouldn’t move)
  • don’t move too many teeth at once
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22
Q

Advantages of URAs

A
  • tipping of teeth
  • excellent anchorage
  • generally cheaper than fixed
  • shorter chairside time required
  • OH easier to maintain
  • Non-destructive to tooth surface
  • less specialised training required to manage
  • can be easily adapted for overbite reduction
  • can achieve block movements
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23
Q

Disadvantages of URAs

A
  • less precise control of tooth movement
  • can be easily removed by patient
  • generally only 1-2 teeth can be moved at one time
  • specialist technical staff required to construct the appliances
  • rotations very difficult to correct
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24
Q

What is the function of an adam’s clasp

A
  • retentive component for removable appliances
  • achieves retention by utilising mesial and distal undercuts
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25
Q

advantages of adam’s clasps

A
  • small and unobtrusive
  • can be used on permanent, primary and partially erupted teeth
  • the bridge provides site of removal
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26
Q

what active component might you use when constructing a URA to retract 13 and 23 after extracting 1st premolars

A

13 +23 palatal finger springs and guards; 0.5mm HSSW

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27
Q

What to do when fitting the appliance for the 1st time

A
  1. ensure it’s the right appliance for the right patient
  2. make sure it’s what you asked for (matches the prescription)
  3. run finger around the fitting surface ensuring no areas of sharpness or bits of wire that could traumatise the patient
  4. check the integrity of the appliance (no damage to the wire or work hardening)
  5. try it on patient and make sure there are no signs of blanching (areas that could traumatise the patient)
  6. check posterior and anterior retention
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28
Q

How do you activate the appliance

A
  • know what tooth movement we’re trying to achieve
  • once you get the appliance get it working from day 1 or will just extend treatment
  • activate to induce 1mm of tooth movement per month
  • demonstrate to patient the correct way to insert and remove the appliance and then get them to demonstrate it back to you
  • book review appointment for every 4-6 weeks
  • you have to activate it every time 1mm moves
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29
Q

How do teeth move

A
  • force exerted creates pressure which causes the bone around the tooth to remodel
  • bone is selectively removed in some areas and added in others
  • the remodelling of the bone is controlled by the PDL fibres
  • we want frontal resorption by stimulating osteoblasts and osteoclasts
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30
Q

what do we use to reduce the overbite

A

flat anterior bite-plane (FABP)

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31
Q

how big should the flat anterior bite plane be

A

overjet + 3mm

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32
Q

how does the flat anterior bite plane work

A

Build up an area anteiorrly

When the pt bites together it props the bite open slightly

Therefore it opens the posteriors

Now created a temporary open bite

Over period of time the posterior teeth will continue to erupt (not over erupt as bone will still remodel in soft tissue in younger patients)

Mainly the lowers which go up rather than the uppers going down as you have the appliance which tends to hold in position

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33
Q

why does the flat anterior bite plane need to be overjet +3mm big

A

If the +3mm wasn’t there could very easily have the lower teeth go behind and push them backwards which would increase the overjet

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34
Q

what are flat anterior bite planes only ever used in?

A

the correction of overbite

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35
Q

why do flat anterior bite planes only work in younger patient

A

Over period of time the posterior teeth will continue to erupt (not over erupt as bone will still remodel in soft tissue in younger patients)

Mainly the lowers which go up rather than the uppers going down as you have the appliance which tends to hold in position

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36
Q

what are some uses of study models

A
  • looking for diagnosis
  • forming treatment plan
  • designing appliances
  • 3D representation of dentition
  • record keeping
  • can measure how successful treatment has been
  • evaluating treatmnt
  • have an idea of what treatment could end up like
  • medico legal reasons
  • patient motivation
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37
Q

What gauge of wire do retentive components have

A

0.7mm HSSW

includes: Adam’s clasps, southend clasps and labial bows
n. b Adam’s clasps - 0.6mm HSSW on primary teeth

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38
Q

What gauge of wire do Active components have

A

0.5mm HSSW

includes: finger springs + guard, Z-springs, flapper sprints, T springs, Buccal canine retractor and roberts retractor

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39
Q

what guage of wire is used for stops

A

0.7mm HSSW

40
Q

why is tubing needed on buccal canine retractor and roberts retractor, and what gauge of wire is used

A
  • We put tubing over it to give strength and rigidity because on buccal aspect can be easily distorted
  • 0.5mm HSSW
41
Q

what function do stops have

A

passive components (not part of ARAB), just hold teeth in position

42
Q

what do buccal canine retractors do

A

move canines back which are not in the line of arch

43
Q

what would we write in the description of active component if needing buccal canine retractors

A

e.g. 13 + 23 buccal canine retractors; 0.5mm HSSW + 0.5 I.D tubing

44
Q

how do you draw a buccal canine retractor

A
45
Q

what is the aim of the buccal canine retractor

A
  • distalise tooth
  • bring in palatally
46
Q

why is it important that the wire work goes to the mesial of 5 on a buccal canine retractor

A

any further forward and the canine couldn’t move past (?)

47
Q

Difficulties of URAs to explain to patients

A
  1. feels big and bulky in mouth
  2. mild discomfort or pressure
  3. will likely affect speech
    1. practice reading aloud, tongue will adapt
  4. salivary response as something is in the mouth
    1. will adapt in about 24 hours
48
Q

Patient instructions for wearing URA

A
  1. wear it 24/7, including eating and sleeping
  2. take it out after every meal and clean with a soft brush
  3. take it out when participating in contact or active sports
  4. avoid hard and sticky foods and be cautious with hot food and drinks
  5. non-compliance will significantly lengthen treatment
  6. emergency contact details
49
Q

what active component fixes an anterior crossbite

A

Z spring; 0.5 HSSW

50
Q

what can’t we use when fixing an anterior crossbite

A

a southend clasp

51
Q

how can we get retention when fixing an anterior crossbite

A

Adam’s clasps on 4s (labial bow also possible but not the best)

52
Q

apart from the Z spring and retentive elements, what else do we need to fix an anterior crossbite

A

Posterior bite plane

  • Props the bite open and allows the tooth to be pushed forward and then we drop it down again
  • We must ensure that all posterior teeth are included and all lower teeth need to engage against it.
53
Q

why does a posterior bite plane not cause continued/over eruption of anterior teeth

A

In humans, when their anteiror teeth have reached their max eruption level they just stop. Some animals their teeth erupt throughout their whole life e.g. rabbits, gerbils, rats. Continually having to wear away their anteiror teeth or they will overerupt so much that they can’t put food in their mouths

54
Q

What would be a suitable URA design for:

  • retract buccally placed canine 13
  • retract canine 23 in the line of arch
  • 1st premolars extracted
  • 6mm (OJ)
  • Reduce (OB)
A

Aim: please construct a URA to retract canines. Buccally placed 13, 23 in the line of arch + reduce OB

Active component: 13 buccal canine retractor, 0.5 HSSW + 0.5 I.D tubuing; 23 palatal fingerspring + guard, 0.5 HSSW

Retentive: 16 + 26 Adam’s clasps, 0.7 HSSW, 11 + 21 Southend clasp, 0.7 HSSW

Anchorage: only moving 2 teeth (tick)

Baseplate: Self cure PMMA; Flat anterior bite plane; overjet + 3mm

55
Q

Where does the adams clasp engage

A

undercut

56
Q

what part of the Adams clasp engages in the undercut

A

arrowhead

57
Q

what is the function of the bridge

A

keeps cheeks away and gives patient something to hold on to

58
Q

what is the interdental part of the adams clasp called

A

flyover

59
Q

What is attached to the flyover on an adam’s clasp

A

the leg

60
Q

what is attached to the leg of an adam’s clasp and is used for mechanical retention

A

tag

61
Q

what covers the tag and the leg of the adams clasp

A

the baseplate (PMMA)

62
Q

if the adam’s clasp wire bends when taking in and out how do you fix this

A

adjust from the flyover first, then the arrowhead

63
Q

what happens if you adjust the arrowhead before the flyover on an adam’s clasp

A
  • occlusion would prop open
  • metal fatigue. Could fracture and patient could inhale/ingest
  • could make the arrowhead damage the gingiva (gum stripper)
  • could distort it and make it no longer functional
64
Q

what are the different parts of an adams clasp called

A
65
Q

function of a finger spring adjustment

A

to move a tooth straight back

66
Q

what are the different parts to a finger spring adjustment called

A
67
Q

how do you activate a finger spring

A

by uncoiling it at coil and at active arm

68
Q

what do you need to do to the active arm of the finger spring as the tooth moves

A

tighten it to stop it drifting buccally

69
Q

2 reasons why the finger spring needs adjusting as it moves the tooth

A
  • distance is shorter
  • coil is activated by uncoiling
70
Q

How do you fit a URA

A
  1. Ensure the patient’s details match the details supplied for the appliance
  2. check the appliance matches the design specifications
  3. inspect the appliance and run your finger over all surfaces looking for sharp or potentially traumatic areas
  4. check the integrity of the wirework (damage or work-hardening)
  5. insert the appliance into the patients mouth, immediately looking for areas of blanching or soft tissue trauma
  6. check the posterior retention (Adam’s clasp, firstly the flyovers, then the arrowheads are correctly engaging the appropriate undercuts)
  7. apply the same principles to the anterior retention
  8. activate the appliance (1mm movement approx per month)
  9. demonstrate to the patient the correct procedure for the insertion and removal of the appliance (ensure that the patient demonstrates this correctly)
  10. book a review appointment in 4-6 weeks
71
Q

what active component would you use to reduce the overjet of 22,21,11 and 12

A

roberts retractor, 0.5mm HSSW, 0.5mm I.D tubing

72
Q

why is internal tubing needed on a roberts retractor

A

so it doesn’t get distorted

73
Q

how do we stop the canines from drifting forward when we want to move 22,21,11 and 12 back

A

by using mesial stops, 0.7mm (flattened) HSSW

74
Q

what are stops with a roberts retractor drawn like

A
75
Q

what do we use for rentention when using a roberts retractor

A
  • Adam’s clasps

nb cannot use southend. The roberts retractor is NOT a retentive component but it does inadvertantly offer some anterior retention (never put it down as retentive though)

76
Q

why is moving 4 teeth with a roberts retractor still ok for anchorage

A
  • We can only get away with it because they are the shorted rooted teeth
  • Even though recommendation is 1 or 2 teeth
  • Keep close eye
  • Also we have support from molars and basepalte
77
Q

why are mesial stops to stop canines relapsing done using 0.7 HSSW (flattened) wire

A

to take up less space round the canines

78
Q

what do we need to think about when using a roberts retractor alongside a flat anterior bite plane (to reduce overbite)

A

the FABP is in the way of the anterior teeth tipping back so need to trim the FABP a bit each visit

79
Q

why couldn’t you just use a posterior bite plane with a roberts retractor instead of an anterior one

A

If you had a posteiror bite plane instead, as soon as you take it your uppers will relapse and lowers will hit palatal

80
Q

what effect does the roberts retractor have on the overbite

A

increases it because of tipping

81
Q

patient information and instructions for URAs

A
  1. appliance will feel big and bulky
  2. may cuase initial excessive salivation
  3. may impinge speech for a short period of time
  4. may cause initial discomfort or ache
  5. to be worn 24/7 including meal times and sleep
  6. remove after every meal and clean with a soft brush
  7. remove and store in a protective container when participating in contact or active sports
  8. avoid hard or sticky foods that may damage the appliance and be cautious with hot food or drinks
  9. missing appointments and non-compliance will significantly lengthen the treatment time
  10. provide emergency contact details in case any problems arise
82
Q

why would we want to expand the upper arch

A
  • creates more space
  • helps posterior crossbite
83
Q

what active component would we use to expand the upper arch

A

midline palatal screw

84
Q

how is the midline palatal screw activated

A

patient turns the screw

85
Q

would we want a southend clasp when trying to expand the upper arch

A

no

86
Q

what can we use for retention instead of a southend clasp when trying to expand the upper arch

A
  • 16 +26 Adams clasps; 0.7mm HSSW
  • 14 +24 Adams clasps; 0.7mm HSSW
87
Q

do we have anchorage when expanding the upper arch

A

called reciprocal anchorage (not really)

88
Q

what could inhibit the arch from moving wider?

A

the lower teeth

89
Q

how do we fix the problem of the lower teeth inhibiting the upper arch from expanding

A

posterior bite plane

90
Q

If we wanted to just expand the upper left posterior quadrant what could we do

A

change where the cut is in the appliance

91
Q

if we wanted to expand all posteriors what could we do

A
92
Q

what active component do we use to fix a 12 in anterior crossbite

A

Z spring 0.5mm HSSW

93
Q

apart from tipping movement, what other movement can we achieve with a Z spring

A

very small amount of rotation

94
Q

how do the coils on the Z spring impact the way the tooth is rotated

A
95
Q

what teeth can Z springs be used on

A

laterals and centrals

96
Q
A

BDS3 Ortho Lab (2 decks)

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