Power Instrumentation Flashcards
When were ultrasonic instruments introduced?
1950’s
What is the biggest advantage of powered instrumentation?
Reduces hand fatigue
What are the modes of action of ultrasonic scalers?
- Mechanical removal
- Water irrigation
Mechanical removal
Rapid vibrations in tip create microfractures in calculus
Water irrigation
- Water flowing over tip disspates heat produced; cooling effect
- Flushes bacteria from pocket
- Hydrodynamic waves disrupt surface bacteria
What is fluid lavage?
Water stream within the perio pocket
What is acoutic microstreaming?
Swirling effect produced within the pocket by stream of fluid flowing over vibrating tip
What is cavitation?
Formation of tiny bubbles in the water stream that happens when the water makes contact with the tip
What are the benefits of powered instrumentation?
Removal of calculus and plaque biofilms
Pocket penetration- slim tip
Access to furcations
Irrigation
Shorter instrumentation time
Reduced hand fatigue
What are the limitations of powered instrumentation?
Clinician skill level
Reduced tactile sensitivity
Infection controlAerosol production
Musculoskeletal and auditory damage
Clinician skill level as a limitation
Skill level is a predictor of outcomes
Powere dinstrumentation is technique-sensitive
Clinicians must understand root anatomy
Infection control as a limitation
Infection control can be compromised b/c some devices have components which cannot be sterilized
Contraindications for use of powered instruments
- 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)
What can be caused by improper tip application?
- Chips
- Roughness
- Remove glaze on porcelain
- Scratch amalgams
- Create pores in restorative materials
What are the two major types of electronically powered devices?
- Sonic
- Ultrasonic (Piezoelectric, Magnetirestrictive [cavitron])
What are sonic handpieces driven by?
Compressed air
Eliptical motion
When should sonic instruments not be used?
On heavy calc (weaker)
What are the benefits of sonic instruments?
Create less heat, reducing risk of tooth damage
Better for inexperienced personnel
Disadvantages of sonic instruments
Extremely slow, relatively
Low range of vibration and high tip amplitude- no cavitation
Noisy
What is the speed range for magnetorestrictive devices?
18,000-45,000 cps
What is the range of speed for piezoelectric devices?
25,000-50,000 cps
What part of the piezo tip is active?
Only the lateral sides- moves in a linear pattern forward and backward
Shaped like a trapezoid
Advantages of the piezo
Quiet
Requires less water
Lightweight handpiece
Small inserts
Color coded power dial
Smaller design
Disadvantages of piezo
Tops are small and can be lost
Requires a key
Shorter working length
Which parts of the magnetostrictice tips are active?
All sides are active
Elliptical motion
What speed to the magnetostrictive devices operate at?
30,000kHz but insert says 25-30
(older units 25,000)
What are the magnetostrictive instrument inserts composed of?
- Longitudinal stack of metal strips- nickel based alloy
- Magnetic field created by expansion and contraction of stacks
- Transforms energy into power, causing vibrations
What are the advantages of magnetostrictive device?
- Many insert options
- Technology is well proven
- Great for stainand calculus removal
What are the disadvantages of magnetostrictive devices?
- Stacks can bend easily
- Produces a lot of heat
- Long skinny handpiece- not ergonomic
- Whole handpiece vibrates- reduces tactile sensitivity
What are standard diameter tips good for?
- Larger diameter tips
- Shorter shank length
- Heavy deposit removal
- Mostly for supragingival
What are slim diamater tips used for?
- 40% smaller in diameter
- Lomger shank length
- Increased tactile sensitivity
- Light-med deposits and de-plaquing
- Subgingival use or tight areas (furcations!)
For every 1mm of tip wear, how much of a loss in calculus removal do we see? After 2mm?
25% less after 1mm, 50% at 2mm
Which part of the instrument tip produces the most energy? And the least?
Point of tip is most powerful
Lateral surfaces are least powerful
(face and back are in between)
What is the portion of the instrument tip capable doing work called?
Active tip area (akin to the “cutting edge”)
