Material

Question 1

Archwires

Answer 1

• Stainless steel
• Cobalt chromium
• Nickel titanium (Niti)
• TMA - Titanium Molybdenum Alloy (beta titanium)
• Aesthetic

Question 2

Nickel titanium (Types of Niti)

Answer 2

• Classic
• Superelastic
• Heat activated

Question 3

Initial Aligning wires properties?

Answer 3

• Low stiffness
• Low friction
• large Range
• light continuous force
• Non toxic
• low cost

Question 4

Initial alignment wire options?

Answer 4

• Superelastic Niti - 0.012” to 0.014”
• Heat activated Niti - 0.016” to 0.020 “
• 0.010” single strand SS
• 0.015” - 0.018” Multi strand SS

Question 5

Nickel Titanium 3 choices

Answer 5

• Martensitic stable - Classic e.g. Nitinol
• Austenitic active - Superelastic or pseudo elastic.
• Martensitic active - Heat or thermally activated.

Question 6

Properties of Niti ?

Answer 6

• Good range
• No elasticity
• high friction
• low stifness
• poor bio host
• bio compatible

Question 7

Properties of Stainless steel?

Answer 7

• large elasticity
• high stifness
• corrosion resistance
• low friction
• good for space closure because of Low friction
• bio host

Question 8

Properties of TMA? Or beta- titanium ?

Answer 8

• Elasticity less than SS but twice that of nitinol
• Higher firction than ss
• high cost
• formability good

Question 9

Aesthetic wires

Answer 9

• Coated wires - White epoxy resin e.g Teflon

Question 10

What wire sequence should we use?

Answer 10

• Initial alignment - Light and limited
• Levelling - heavier and limited
• Space closure - Stiff & low friction
• Finishing - Formable

Question 11

Define friction

Answer 11

• A force resist relative motion of two objects in contact.

Question 12

Law of friction

Answer 12

Friction = Force x coefficient of friction

Question 13

Types of friction

Answer 13

• Static friction - Small amount of force required to initiate sliding between objects
• Kinetic friction - Amount of force resisting sliding once moving.

Important : Static friction more important as teeth do not slide but Walk along arch wire with small tippping and uprighting movements.

Question 14

Bracket material - Friction

Answer 14

• Ceramic > friction than metal
• Narrow bracket > friction than wider bracket (due to critical angle)

Question 15

Wire material - Friction

Answer 15

• Beta- titanium > friction than Niti > friction than SS.

Question 16

Ligation material - Friction

Answer 16

• Elastomeric ligature > friction than SS ligature
• 60%- 70% more

Question 17

Which moment effect by friction ?

Answer 17

• Tipping and bodily moment

Question 18

Bracket material types?

Answer 18

• Metal
• Ceramic
• Polycarbonate
  -Polyurethane

Question 19

Morphology of brackets?

Answer 19

• Siamese
• Mini twin
  -Single twin
• Self ligating
• Tip-edge

Question 20

Slot size

Answer 20

• 0.018X 0.028
• 22x28 common uk
• 22x30 eases tying auxiliary/piggybacks

Question 21

Bracket - Metal

Answer 21

• Austentistic stainless steel
• If NiTi allergy can consider : Titanium , Cobalt chromium

Question 22

Bracket - Bases

Answer 22

• Mesh commonly used fine or coarse, single 2 and 3 ply available
• Spherical photo etched undercut
• Undercut channels
• Polymer coated

Question 23

Bracket - Configuration

Answer 23

• Straightwire or Pre adjusted edgewise system
• Commonly used we

Question 24

Bracket - Siamese

Answer 24

• Four tie wings for better rotational control

Question 25

Bracket - Self ligation

Answer 25

- Speed - In - Ovation - smart clip - Damon

Question 26

Bracket - 22x28

Answer 26

- most common in UK 0.022 height - 0.028 width - Some brackets are deeper

Question 27

Andrews prescription

Answer 27

- This is from originator of pre adjusted edgewise appliance system

Question 28

MBT prescription

Answer 28

- More lingual crown torque lower LBS - less crown torque lower second molar. - More labial torque upper incisors - reduced tip

Question 29

Self ligating brackets - Advantages

Answer 29

- Full archwire engagement - Less Charside assistance required - Less chair side time required - less number of appointments - Improved infection control

Question 30

Self ligating - Disadvantage

Answer 30

- Takes practice - Clip fracture / open b/w appointment -No partial ligation - wire sliding round - Cost - no evidence of faster alingment

Question 31

Why static friction?

Answer 31

- Teeth do not slide but walk with along archwire with small tipping and uprighting movements

Question 32

Begg appliance

Answer 32

- Light wire appliance

Question 33

What's range

Answer 33

- Distance wire behaves elastically before deform

Question 34

Define strength

Answer 34

- Stifness x strain

Question 35

Formablity

Answer 35

- amount of permanent deformation without fracture

Question 36

SS wire composition

Answer 36

- 71 % Fe - 18% Cr - 8 Ni

Question 37

Niti composition

Answer 37

-52% Ni - 43% -3%

Question 38

Cobalt chromium

Answer 38

- 40% Co - 20 % Cr - 15% Ni - 15 % Fe -

Question 39

GIC made of?

Answer 39

- Glass poly alkenoate cement

Question 40

GIC - Band cement types

Answer 40

- Conventional glass ionomer - acid / base cement reaction - Resin modified GIC- dual cure -acid base light cure - Resin modified GIC - tri cure - Acid base / light cure/ chemical - Compomer - Acid base reaction / chemical or light

Question 41

Composite

Answer 41

- Resin BisGMA. Coupling agent - Usually filled diacrylics

Question 42

Unfilled resin primer - Bond

Answer 42

- Methyl methacrylate monomer

Question 43

Self etch

Answer 43

- decreased no of steps in bond up - Decreased enamel loss during etch - Do not require rinsing , pt comfort - Clinical performance as good as conventional