5: Ultrasonic Scaling

Question 1

what is the aim of periodontal treatment?

Answer 1

reduce pathogens in subgingival biofilm to a level conducive to healing

Question 2

how are the aims of periodontal treatment achieved?

Answer 2

through mechanical debridement, either hand or powered (ultrasonic) instruments

Question 3

what are the factors considered while choosing between a hand or powered scale?

Answer 3

• the patient
• the deposit
• the site to be accessed
• the skill/experience of operator
• time (in general practice)

Question 4

what are power scalers and how are their forces generated?

Answer 4

• ultrasonic: generated from piezo-electricity or magnetostriction
• sonic: generated from passage of compressed air

Question 5

sonic scalers:
working tip oscillates at what frequency?
generated by?
tip movement?
examples?

Answer 5

• 6-8kHz
• generated by passage of air over rod which vibrates
• elliptical, almost circular
• micro-mega, titan, kavo

Question 6

ultrasonic scalers:
working tip oscillates at what frequency?
force generated from?

Answer 6

• 25-42kHz

- force generated from piezo-electrcity or magnetostriction

Question 7

piezo-electric ultrasonic scalers: what is their mechanism? examples?

Answer 7

• incorporates a crystal of piezo-electric material which oscillates in an electromagnetic field
• ENAC, piezon, satelec

Question 8

magnetostrictive ultrasonic scalers: tips are connected to? what is the effect of it? mechanism? examples?

Answer 8

• connected to magnetostrictive ‘stack’ which inserts into a coil in the handle
• changes dimension in electromagnetic field
• current moving through the coil causes stack to oscillate/vibrate, a nd is passed to the tip
• cavitron, scalrton, odontosonic

Question 9

power scalers: what are their aims? how do they achieve these aims?

Answer 9

• mechanically remove deposits: through oscillation/vibration of tip
• exert biophysical effects: through cavitation and acoustic microstreaming

Question 10

what is acoustic microstreaming? what does it generate?

Answer 10

movement of fluid adjacent to vibrating tip

- generates stresses within immediate area, thereby damaging bacterial cell membrane

Question 11

how does cavitation work?

Answer 11

formation of vibrating micro-bubbles, expanding to several times their original size
internal temp & pressure increase -> bubble collapses
collapse of bubble -> shock wave -> deposit removal and damages bacterial cells

Question 12

what happens when cavitation action is too strong?

Answer 12

tissue damage may occur

Question 13

how does cavitation and acoustic microstreaming work together?
how do its effects aid biofilm removal?

Answer 13

• if cavitation does not occur, A.M. does not occur either
• they cause biofilm removal by affecting the permeability of bacterial cell membrane, altering bacterial processes including release of cell contents, resulting in lysis

Question 14

when are power scalers useful and NOT useful?

Answer 14

useful for: hard deposits, tight narrow pockets and furcations
not useful for: soft plaque

Question 15

what are some cautions for ultrasonic/sonic scalers? x7

Answer 15

• emit electromagnetic radiation: interfere with cardiac pacemakers, do not use on patients with inwelling cardiac devices even if they are modern
• generate aerosols: don’t use on patients with Tb, throat and respiratory infections. don’t use on patients with HIV, hep c, hep b. don’t use on patients who cannot tolerate high volume aspiration
• thermal damage to tooth/periodontium, requires coolant of at least 20ml/min
• incorrect angulation: potential tooth damage
• can cavitate lesions in areas of decalcified enamel
• auditory hazard, though never proven
• vibration to operator said to cause neurological damage with prolonged use.

Question 16

advantages of power scalers? x6

Answer 16

• simple and effective (1/3rd less time than hand scaling)
• can be used supra & sub gingivally
• no instrument sharpening required
• water spray provides constant lavage and irrigation
• useful in tight pockets: less tissue distortion
• useful with restricted access (furcations)

Question 17

disadvantages of powered scalers x6?

Answer 17

• some patients cannot tolerate vibration/coolant
• water spray must be managed, if not difficult to see
• aerosols
• expensive to purchase
• potential increased damage to root surface compared to hand instruments if used incorrectly.

Question 18

using power scalers on ceramics - why does caution need to be taken?
what is at risk when scaling restorations/fixed prosthodontics?

Answer 18

• caution required as ceramics are highly glazed: surface can be scratched
• restorations and fixed prosthodontics can de-bond or de-cement while scaling: re-cement or place provisional restoration?

Question 19

using power scalers on implants: what needs to be changed when scaling implants?

Answer 19

need to use alternative scaler tips, carbon and plastic tips for ultrasonic efficacy?

Question 20

what is considered incorrect angulation of the ultrasonic scaler?

Answer 20

never hold end of tip pointing into tooth as high energy will damage tooth surface

Question 21

movement of tip should be in what position?

Answer 21

parallel to long axis of tooth

Question 22

using the ultrasonic: points to remember? x 4

Answer 22

light, sweeping stroke
no pressure on tip
keep tip moving at all times
minimize number of strokes required

Question 23

how can the scaling be further completed?

Answer 23

use hand instruments to further smooth the root surface, e.g. if carrying out root surface debridement