Homework Questions Flashcards

1
Q

Which tooth sometime has additional cusp?

A
  • Upper first maxillary molar
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2
Q

That extra cusp called?

A
  • Cusp of Carabelli
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3
Q

Which group of teeth are present in the permanent dentition that are not present in primary dentition?

A
  • Premolars
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4
Q

State difference between permanent and primary teeth

A
  • Primary teeth are
  • smaller than permanent teeth
  • enamel is thinner than permanent teeth
  • Roots are shorter than permanent teeth
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5
Q

What is leeway space and how it’s relevant in orthodontics?

A
  • So when these primary teeth exfoliate, there is slight amount of space (2.5mm per side) in lower arch and 1.5mm per side in upper arch. This space allows forward movement of molars and therefore achieve class 1 molar relationship.
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6
Q

What age canine palpable ?

A
  • 10 yrs
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7
Q

At what age does upper central incisor develop?

A
  • 3-4 months
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8
Q

What sequence does the permanent dentition erupts?

A
  • Maxilla- 6,1,2,4,5,3,7,8
  • Mandible- 6, 1,2,3,4,5,7,8
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9
Q

Describe properties of Nickel Titanium wires which make them a common arch wire choice in initial aligning process?

A
  • Shape memory
  • Good springback
  • High stored energy
  • Low friction
  • low stiffness
  • light continuous force
  • Large range of action
  • Non toxic
    -Poor biohost
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10
Q

Define Range

A
  • Distance wire behaves elastically before it deforms
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11
Q

Define Formability

A
  • The amount of permanent deformation that can occur without fracture
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12
Q

Define Stiffness

A
  • amount of force to bend wire.
  • Low stiffness provides the ability to apply lower forces and more consistent force over time
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13
Q

Friction

A
  • The force that opposes a movement when object moves against another.
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14
Q

Define Anealing

A
  • It changes elastic properties of arch wire distal end as become formable like Niti wire which helps to cinch back
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15
Q

Describe properties of Heat Activated Niti wire and why it might be prescribed?

A
  • Heat activated are Martensitic active.
  • Thermally activated shape memory.
  • Thermal activation can be set at different temperatures (TTR)
  • Cool down below TTR - Martensitic less stiff/ easily deformed
  • Heat above TTR - Austentistic and return to original shape
  • Heat activated Niti wires helps teeth move quickly and effectively giving more comfortable treatment experience and reducing overall treatment time.
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16
Q

What is incidence of missing laterals incisors?

A
  • 2%
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17
Q

Please list the teeth below into order.
1 most commonly absent to least commonly absent

A
  • 8s’
  • Lower second premolars
  • upper lateral incisors
  • Upper second premolars
  • Lower incisors
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18
Q

Please give me 3 reasons why orthodontist may plan to open space rather than close space for missing lateral incisors

A
  • Colour from canine to central incisor
  • Shape of canine
  • Position of adjacent teeth/ intercuspation
  • Space closer may be slower
  • Age of patient
  • Cost of implication for implant
  • Attitude of family
  • Function of teeth
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19
Q

Some ortho may choose to place lateral bracket on canine in cases when they plan to place the upper canine in lateral incisor position, Advantages and disadvantages of this decision?

A
  • Advantages- Bracket prescription best represents ideal lateral position - In term tip and toque
  • Disadvantage- Base doesn’t fit contours of tooth that mean prescription is not fully expressed. Also it is small bracket for large tooth with large root and this is another reason the prescription would not be faithfully realised .
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20
Q

What is IOTN score for patient hypodontia and what is difference between?

A
  • 4h- Need treatment - less severe hypodontia requiring pre restorative orthodontics or space closure to prevent need or restoration
  • 5h - Need treatment- Extensive hypodontia with restorative implication - More than 1 tooth missing per side. Require pre- restorative orthodontic.
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21
Q
  • List 3 methods of measuring crowding in primary dentition?
A
  • Contact point of displacement
  • Brass wire to measure tooth/ arch ratio
  • Digitally
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22
Q

What are the measurements to differentiate between the amount of crowding?

A
  • 0-4mm mild
  • 4- 8mm mod
  • more than 8 severe
23
Q

The primary 2nd molar was removed aged 9 space maintainer was fitted. Describe space maintainer that could be used in upper arch?

A
  • URA
  • Cribs 6/6 ( 4’s also if erupted)
  • 1/1 Southed clasp
  • Acrylic baseplate
24
Q

Describe a space maintainer that could be used in lower arch

A
  • The band and loop space maintainer
  • Consist of SS bands that surrounds tooth with loop that juts outwards.
  • This spacer maintains distance between the teeth to ensure that there’s sufficient space for the not - yet- emerged tooth to grow without crowding and over lapping other teeth
25
Q

What are the potential / documented causes of late lower incisor crowding in untreated patient ?

A
  • Inherent mesial migration
  • Facial growth pattern and rotation
  • Soft tissue pressure
  • Jaw size decreasing with age
  • Narrow contact points of lower incisors
26
Q

Define Bolton analysis

A
  • Ratio of mesiodistal widths of maxillary teeth to Mandibular teeth.
  • It helps in determining disproportions in the size between maxillary and Mandibular teeth.
  • It helps to determine the optimum inter arch relationships.
  • This analysis measures mesio- distal width of each tooth and divided into two analysis
27
Q

Properties of stainless steel for later stage of orthodontic

A
  • High stiffness good space closure
  • Large elasticity
  • Non corrosive
  • Shorter range
  • Poor biohost
  • low friction for space closer
28
Q

4 methods of active space closure

A
  • Powerchain
  • Powerthread
  • Niti coil springs
  • E-links
  • Bennettes modules
29
Q

2 ways of space closing?

A
  • Sliding mechanism
  • En masse space closure
  • Distalising canine into class 1 with 2 stage space closure.
30
Q

3 reasons for bonding / banding 2nd molar

A
  • Anchorage
  • Overbite reduction
  • Straightening
  • Overjet reduction
  • Orthognathic surgery
  • Expansion
31
Q

Describe the physiological process of tooth movement when an optimum force applied to the tooth

A
  • The optimal force for tooth movement is below capillary pressure which is 20-25g/cm2.
  • The pressure side- Periodontal ligament is compressed. With in seconds the alveolar bone bends and the blood supply is altered. When this pressure is continued over a period of hours there is chemical reaction within blood cells which release Cykotonis (Cytokines) and prostoglandis which in turn signals the need for osteoclasts to migrate to the area.
    Within two days osteoclasts migrate to the area and begin bone resorption, which allow the teeth to move.

Tension side- PDL is stretched which again alter the capillary pressure and blood flow but this time in different way. This signals need for osteoblasts and fibroblasts to migrate to the area and lay down osteoids onto socket wall and new PDL fibre.

32
Q

Make reference to the main cells involved? Timeframe involved?

A
  • Pressure side 1-5 seconds - PDL compressed, change in cell shape.
    -Minutes- O2 level change , chemical released e.g. Prostaglandin and cytokines.
    -4 hours - Osteoclasts differentiate.
33
Q

Types of tooth movement ?

A
  • Bodily movement - 50-120 g
  • Tipping movement - 25-60g
  • Extrusion - 35-60g
  • Intrusion - 10-20g
  • Rotation - 35-60g
34
Q

Describe physiological process of tooth movement that occurs when the force applied is very high

A

1- Pressure side- PDL is compressed as tooth moves within socket which occlude the capillaries and blood flow is stopped within a matter of minutes. If this pressure is sustained within an hour cell death will occur. This known as sterile necrosis of hyalinisation. This gives the appearance of glass if it were to be examined under microscope. Cell proliferation begins in surrounding areas of bone which have been compressed but not occluded thus causing undermining resorption of alveolar bone. 7-10 days later the cell proliferation migrate to hyalinised area which then leads to tooth movement . Tooth movement is therefore more painful and delayed.

2- Tension side- On tension side the movement is exactly the same as optimal pressure. However delayed owing to the lack of movement for first 7-10 days owing to the lack of movement on pressure side

On pressure side the PDL is stretched which again alters the capillary pressure and blood flow but this time in a different way. This signals the need for osteoblast and fibroblast to migrate to the area and lay down osteoids onto socket wall and new PDL fibres. Osteoids is premature bone and jelly consistency which is why teeth can feel mobile until they have settled. The osteoids becomes calcified within six weeks and mature into woven bone. It later remodels to become mature bone.

35
Q

Time frame for excessive force

A
  • Heavy force - Above capillary blood pressure
  • Seconds - Blood vessels occlude on pressure side , stretched , raptured on tension side
  • Minutes - Blood flow cut to pressure side - Hyalinisation
  • HYALINISATION
  • (3-5 days)- Cells differentiate at distant site- UNDERMINING RESORPTION
  • (7-14 days)-Tooth movement occurs
36
Q

How much space closure in mm do we usually expect per month?

A
  • 1mm
37
Q

8 reasons for possible reason for slow space closure during this phase in a patient wearing fixed appliance

A
  • Insufficient force
  • Too much force (hyalinisation)
  • Binding of the archwire
  • blockage of molar tube / archwire stuck in molar tube
  • Root touching
  • Necking of alveolar bone
  • Bent archwire
  • Calculus on archwire / slot
  • Ankylosed tooth
  • Broken / lost chain
  • Archwire not passive- increased friction
38
Q

What do the letter COSHH stand for?

A
  • Control of substances hazardous to health
39
Q

List 8 steps that are needed to comply with COSHH regulation ?

A
  • Conduct a COSHH risk assessment
  • Eliminate any risks
  • Implement control measures
  • Review control measures
  • Develop emergency procedures
  • Monitor workplace exposure levels
  • Conduct health surveillance
    -Provide information and training
40
Q

The 1947 Health and safety at work act is applicable to

A
  • All the staff in the practice
41
Q

Any incident that happens within practice should be recorded in?

A
  • Accident book
42
Q

RIDDOR stand for

A
  • Reporting of injury disease and dangerous occurrence regulation
43
Q

Report RIDDOR? Incidents

A
  • Being off work for being incapacitated for more than 7 consecutive days
  • Scalding of more than 10% of your body
    -A pt that has fallen off dental chair and has been taken to hospital
  • A pt that has died within the practice
44
Q

List three viral infections of concern following sharp injury

A
  • HIV (human immune deficiency virus)
  • Hep b
  • Hep c
45
Q

List 3 first aid measures that should be followed when skin is cut or penetrated by any sharp object which is contaminated with patient’s blood or saliva

A
  • Encourage bleeding by pressing finger
  • Wash it under runny water and do not scrub
  • Check medical history
  • Cover with waterproof dressing / plaster
46
Q

What does IRMER 2000 stand for and whose protection is it concerned with?

A
  • The ionising radiation medical exposure regulation 2000.
  • Protection of patient
  • Responsibility of Employer, referrer, practitioner operator for radiation protection and basic safety standards
47
Q

What are dental features of thumb sucking habit?

A
  • An anterior open bite or reduced overbite (often with asymmetry) .
  • Increased Overjet
  • Unilateral crossbite ( often with displacement) (Narrow maxillary arch)
  • Posterior crossbite.
48
Q

What duration per day is the habit require to bring about change in tooth position?

A
  • More than 6 hours a day
49
Q

How would you deter this habit? Thumb sucking - also orthodontic intervention

A
  • Encourage: Daily reward system to stop habit.
  • Praise- Encouragement for not sucking thumb
  • Avoid Nagging , teasing or shaming child.
  • Use of physical barrier - Elastoplast, bandage, cotton glove, sock , thumb guard, nasty nail varnish.
  • Orthodontic intervention : habit breaker - appliance which make thumb sucking more difficult.
50
Q

Please complete : An open bite associated with thumb habit often resolves if habit is stopped before

A
  • Before permanent dentition erupts
  • Before upper central incisors erupts
51
Q

Would you start fixed appliances treatment in a patient with active thumb habit?

A
  • No - Unless there is problem that requires to be sorted and the fixed appliances may help them to stop .
52
Q

4 advantages of self lighting bracket

A
  • Good space closure
  • Easy to clean
  • Less chairside
  • Less chair assistance
  • Complete engagement of archwire
  • Low friction
53
Q

What are 2 types of self lighting brackets

A
  • In ovation R and Speed active 0.017”- 0.020”
  • Damon and smart clip passive 0.028”
54
Q

6 instructions you would give to patient on placement of intra oral elastics

A
  • Check if any allergies to latex
  • Take them out when eating, drinking, and playing contact sports for mouth guard and brushing teeth
  • Duration of elastics - Confirm duration of elastics FTW or NTO.
  • Show them where and how to place intra oral elastics
  • If run out please contact us