Lasers 1 Flashcards
Giving off different wavelength than absorbed
Fluorescence
1st dedicated Laser for dental application
Nd-Yag
LASER
Light
Amplification
Stimulated
Emission
Radiation
LED, no
heat
White light
Laser light
everywhere
coherent
Laser light is one
color
Monochromatic
collimated
coherent
laser
Quantum:
photon
photon stimulate atom to emit other photons
Einstein
lasers are one color, colliated, and coherent
True
Spontaneous emmision
Stimulated emission:
no coherency photon randomly released
induced
Spontaneous is random
True
A state in which a substance has been energized or excited to SPECIFIC energy levels
*more atoms/higher excited state
Population Inversion
Population inversion, aka…
pumping
Amplification associated with…
population inversion
Radiation: ionizing
non-ionizing
enough energy to break away from atom
excitation, not breaking away (lasers)
horizontal distance of measurement
wavelength
wavelength measurement
microns
height of wave, equivalent to energy
amplitude
Amplitude is equivalent to…
energy
For a particular laser the horizontal width will always be the same
True
shortest wavelengths, highest amplitude
gamma
Dental lasers operate where
Infrared
Gas or solid
active medium
*emits
Pumping
mirror
external energy
reflection
what gives laser generic name?
Active medium
Rapidly flashing lamp or electrical current field:
Pumping mechanisms
Control panel, delivery system, footswitch
all dental lasers have
modes of operation:
continuous
pulsed
optical fibers, hollow waveguide, articulated arm
delivery
pure photon energy has a max effective distance
True
*this is bell-shap multi-mode
Laser tissue interaction:
reflect
absorb
transmit
scatter
transmit in non-ionizing
nothing happens
scattering
may cause collateral
why use quickly
Absorption is dependent on wavelength and tissue composition
True
Absorption is
Thermal
Chemical
Acoustic
4 tissues
water
hemoglobin
melanin
HA
2 chromophores w/ hard tissue
soft tissue
3 chromophorex of sub epi
water enamel
Water melanin
water, hemoglobin, oxy-Hb
absorber of laser energy
chromophore
Nd:YAG shouldn’t be used with… 40%
implant
Mid-IR Erbium 30%
no implnat
IR CO2 laser 10% Ti absorption
use with implants
photothermal ablation:
activate the tip
Coagulation depth is proportional to
absorption depth
gigival blood diameter:
21-40 microns
Cold steel scalpel:
blood, compression, sutures
Erbium lasers:
absorption won’t damage whole vessel
Diode Laser:
coagulation before cutting
- bleeding very controlled
- photo coagulation widespread and imprecise
CO2 laser:
coeeficinent of absorption equal to…
best margin of ablation to coagulation
best
*cutting and coagulation at same time
Near IR
Mid IR
IR CO2
ineffecient
good ablaters/poor coagulation efficiency
highly efficient and accurate ablaters/excellent coagulators
To achieve hemostasis, tissue temp:
60 C
100 C:
anaerobic bacteria
*photo thermal lysis
excess of 200C
carbonization
***avoid
Light energy changed into what upon tissue interaction
Heat
unit of energy
unit of power
pulses per second
change from solid to vapor
joule
watt
hertz
ablation
Lasers used in diagnostics
True
Near IR targets
melanin, Hb
Activate tip must be ____ hot
red or white
Longer wavelength is of the _____ or _____family
chromophore targets:
Erbium, CO2
water
Long wavelengths cause what?
vaporization
Hard tissue cutting causes ______ and mineral to be ejected
Expansion
*not a smooth cut
optimal effects occur with energy apsorption by:
target tissue
Work
Energy
Power
Avg power
Pulse duration
Hertz
tissue effect
ability to perform work
work/time
sustained over time
emission
pulses/sec
avg power
peak power
beam diameter
energy density
free running
energy/pulse duration
smaller beam, more powerful
Carbon dioxide can go continuous or
superpulsed
Energy distribution w/ more electrons in higher energy state than lower one
Population inversion
ANSI classificaiton:
higher, greater hazard potential
Engineering administrative and porcedural
Laser control measures
primary responsibility
operator
don’t look into a laser!!!
true
Open beam, so eye protection, control, etc
True
Laser recognition lights
should have in office
Class 1 - 4 lasers
1 safest
4 eye hazard
Class IIIA lasers can damage eye
true, but not in a short time
laser pointers
eye injury if look into it for a minute or so
Class IIIB laser,
eye damage if look directly
*no hazardous diffuse reflections
Class IV lasers
light scalpel, etc
can Damage
Hazardous diffuse
High power lasers:
Class IV
Don’t use alcohol when using a laser
True
Eyes, skin are tissues at risk
True
MPE
Max Permissible Exposure
Cross check that you and your pts glasses are appropriate
True
Ablation produces what?
Plume
*protect with mask
NItrous can be used with Lasers
Never work with Pure Oxygen (pt on medical)
True
True
Test fire the laser prior to Pt sitting down
Always test with lowest power setting
True
True
tip size goes down by 2, increase power by
4
