Power Instrumentation

Question 1

When were ultrasonic instruments introduced?

Answer 1

1950’s

Question 2

What is the biggest advantage of powered instrumentation?

Answer 2

Reduces hand fatigue

Question 3

What are the modes of action of ultrasonic scalers?

Answer 3

• Mechanical removal
• Water irrigation

Question 4

Mechanical removal

Answer 4

Rapid vibrations in tip create microfractures in calculus

Question 5

Water irrigation

Answer 5

• Water flowing over tip disspates heat produced; cooling effect
• Flushes bacteria from pocket
• Hydrodynamic waves disrupt surface bacteria

Question 6

What is fluid lavage?

Answer 6

Water stream within the perio pocket

Question 7

What is acoutic microstreaming?

Answer 7

Swirling effect produced within the pocket by stream of fluid flowing over vibrating tip

Question 8

What is cavitation?

Answer 8

Formation of tiny bubbles in the water stream that happens when the water makes contact with the tip

Question 9

What are the benefits of powered instrumentation?

Answer 9

Removal of calculus and plaque biofilms
Pocket penetration- slim tip
Access to furcations
Irrigation
Shorter instrumentation time
Reduced hand fatigue

Question 10

What are the limitations of powered instrumentation?

Answer 10

Clinician skill level
Reduced tactile sensitivity
Infection controlAerosol production
Musculoskeletal and auditory damage

Question 11

Clinician skill level as a limitation

Answer 11

Skill level is a predictor of outcomes
Powere dinstrumentation is technique-sensitive
Clinicians must understand root anatomy

Question 12

Infection control as a limitation

Answer 12

Infection control can be compromised b/c some devices have components which cannot be sterilized

Question 13

Contraindications for use of powered instruments

Answer 13

• Asthma/COPD
• Pacemaker
• Communicable diseases (TB, Hepatitis)
• Individuals with high susceptibility to infection (uncontrolled diabetes, organ transplants, immunosuppressed individuals)
• Pt’s w/ difficulty swallowing (MS, ALS, Parkinsons)
• Age (young pts)
• Oral conditions (hypersensitivity, porcelain crowns, composite resin restorations, exposed dentin, titanium implants)

Question 14

What can be caused by improper tip application?

Answer 14

• Chips
• Roughness
• Remove glaze on porcelain
• Scratch amalgams
• Create pores in restorative materials

Question 15

What are the two major types of electronically powered devices?

Answer 15

• Sonic
• Ultrasonic (Piezoelectric, Magnetirestrictive [cavitron])

Question 16

What are sonic handpieces driven by?

Answer 16

Compressed air
Eliptical motion

Question 17

When should sonic instruments not be used?

Answer 17

On heavy calc (weaker)

Question 18

What are the benefits of sonic instruments?

Answer 18

Create less heat, reducing risk of tooth damage
Better for inexperienced personnel

Question 19

Disadvantages of sonic instruments

Answer 19

Extremely slow, relatively
Low range of vibration and high tip amplitude- no cavitation
Noisy

Question 20

What is the speed range for magnetorestrictive devices?

Answer 20

18,000-45,000 cps

Question 21

What is the range of speed for piezoelectric devices?

Answer 21

25,000-50,000 cps

Question 22

What part of the piezo tip is active?

Answer 22

Only the lateral sides- moves in a linear pattern forward and backward
Shaped like a trapezoid

Question 23

Advantages of the piezo

Answer 23

Quiet
Requires less water
Lightweight handpiece
Small inserts
Color coded power dial
Smaller design

Question 24

Disadvantages of piezo

Answer 24

Tops are small and can be lost
Requires a key
Shorter working length

Question 25

Which parts of the magnetostrictice tips are active?

Answer 25

All sides are active Elliptical motion

Question 26

What speed to the magnetostrictive devices operate at?

Answer 26

30,000kHz but insert says 25-30 (older units 25,000)

Question 27

What are the magnetostrictive instrument inserts composed of?

Answer 27

* Longitudinal stack of metal strips- nickel based alloy * Magnetic field created by expansion and contraction of stacks * Transforms energy into power, causing vibrations

Question 28

What are the advantages of magnetostrictive device?

Answer 28

* Many insert options * Technology is well proven * Great for stainand calculus removal

Question 29

What are the disadvantages of magnetostrictive devices?

Answer 29

* Stacks can bend easily * Produces a lot of heat * Long skinny handpiece- not ergonomic * Whole handpiece vibrates- reduces tactile sensitivity

Question 30

What are standard diameter tips good for?

Answer 30

* Larger diameter tips * Shorter shank length * Heavy deposit removal * Mostly for supragingival

Question 31

What are slim diamater tips used for?

Answer 31

* 40% smaller in diameter * Lomger shank length * Increased tactile sensitivity * Light-med deposits and de-plaquing * Subgingival use or tight areas (furcations!)

Question 32

For every 1mm of tip wear, how much of a loss in calculus removal do we see? After 2mm?

Answer 32

25% less after 1mm, 50% at 2mm

Question 33

Which part of the instrument tip produces the most energy? And the least?

Answer 33

Point of tip is most powerful Lateral surfaces are least powerful (face and back are in between)

Question 34

What is the portion of the instrument tip capable doing work called?

Answer 34

Active tip area (akin to the "cutting edge")