mod 23: powered instrument design and function

powered instrumentation devices

use of a rapid vibrating irrigated working end to dislodge calc from the tooth surface, disrupt biofilm, and flush out bacteria from the periodontal pocket

powered instrumentation in the late 1950s

development of first electronically powered instruments

powered instrumentation in 1960-1970s

powered instruments used to remove heavy calc deposits, mostly supragingival

powered instrumentation in the late 1980s

slim working ends developed

powered instrumentation today

modern powered working ends have been shown to be as effective as hand instruments for removing subgingival deposits, biofilm, and bacterial products

types of powered instrumentation devices 

-sonic powered devices

-ultra sonic powered devices

sonic powered devices

operate at lower frequency of 3,000 to 8,000 cycles per second; not used anymore

ultrasonic powered devices

operates at 18,000 to 45,000 cycles per second

types of ultrasonic powered devices 

-piezoelectric devices (piezo)

-magnetostrictive devices (magneto)

piezo devices

-uses of electrical energy to activate crystals within the handpiece to vibrate the instrument tip

-lateral surface of powered tip are most effective for calc removal

magneto devices

-the transfer of electrical energy to metal stacks made of nickel-iron alloy or to a ferrous rod to vibrate the insert

-all surfaces of powered tip are effective for calc removal

strength of powered instrumentation

-effectively removes supra and sub calc deposits

-effectively removes sub plaque biofilm

-slim tips reach deeper into pockets than hand instruments

-slim tips provide access to furcation areas

-water irrigation flushes bacteria from pockets

limitations of powered instrumentation

-skill level affects outcome

-piezo and magneto are technique sensitive

-less tactile sensitivity

-always have to go back with explorer to check the surface to make sure you didn’t miss any

2 basic types of powered tip

standard tips and slim perio tip

standard tips

-larger in size with shorter shank lengths

-magneto= gross tip

slim perio tips

-up to 40% smaller in size with longer more complex shanks

-magneto= fine tip

standard or gross tip use

-heavy deposit removal

-supra and sub deposits easily accessed without undue tissue distension

slim perio or fine tip use

-light to moderate deposits and deplaquing

-instrumentation of root concavities and furcations

mode of action

-very rapid vibrations of powered working end creates microfractures in calc deposits

-water dissipates heat from rapid vibration

-water flushed toxic products and bacteria from pocket

fluid lavage

constant stream of water exiting near point of working end

mechanisms of action

-frequency 

-amplitude

frequency

measure of how many times a powered working end vibrates per second

amplitude

measure of how far the powered working end moves back and forth

low frequency

tip goes back and forth a few times in a minute 

high frequency

tip goes back and forth multiple times in a minute

low amplitude

delivers a shorter, less powerful stroke

high amplitude

delivers a stronger, more powerful stroke

cleaning efficiency

determined by a combo of frequency and amplitude

low frequency, low amplitude

-fewer vibrations and shorter strokes

-ideal for plaque biofilm removal and lavage

high frequency, high amplitude

-many vibrations and longer strokes

-ideal for tenacious calc deposit removal 

contraindications for powered instrumentation

-review HH before using

-consider aerosol production

-respiratory problems, communicable disease transmission

-susceptibility to infection, cardiac implant device

-sensitive, demineralized teeth

-difficulty swallowing

-titanium implant surfaces (special tip)

approach to calc removal with powered instrument

-work from coronal most region of deposit

-start near CEJ and work apically toward base of pocket

-will not be activated until inserted into sulcus

irrigation flow of piezo device

only working end needs to be cooled by water to prevent over heating

irrigation flow for magneto device

handpiece and working end need to be cooled with water to prevent over heating

rule of thumb for irrigation

use more water than you think necessary

correct stroke technique

requires slow, repetitive strokes to remove calc

rule of thumb for power

set it lower than you think and move up if needed

strokes for calc removal

-gentle pressure

-overlapping vertical or oblique direction

strokes for biofilm removal

-mechanical removal is needed

-low pressure

-working end needs to be moving at all times

-normal sulci with no inflammation does not need to be deplaqued

transverse tip orientation

-tip is positioned with lateral surface in a crosswise orientation to the long axis of the tooth

-this orientation is similar to that of universal curette

vertical tip orientation

-tip is positioned with the lateral surface against the tooth surface 

-similar manner to a probe

-inserting tip in a probe position

instrument tip wear and replacement

-inspect tips regularly

-with use tip is warn down and less effective

-1mm of wear results in 25% less efficiency

-2mm of wear result is 50% less efficiency and should be discarded

active tip area

-portion of instrument tip capable of doing work

-last 2-4 mm of lateral surface

smoothing defective margins

-a specialized powered tip may be used to recontour a defective margin (overhang)

-a smooth surface will deter bacterial accumulation

-diamond coated working end from Hu Friedy is used on amalgam overhangs

-burnett power tip is used on tenacious calc, amalgam overhangs, and ortho cement

cord management

-wrapped up arm

-grabbed in loop in hand

-pinky holds it

fluid control

-anterior cupping

-posterior cupping