LASERS USED IN OPERATIVE DENTISTRY
Prof. H.D.Adhikary Dept. of
Dr.R.Ahmed Dental College & Hospital
History of lasers
Components of lasers
Types of lasers
Application of lasers in operative dentistry
Dentistry has advanced a lot.
Among various advances, one which have good
scope of improvement is the use of lasers in
Recent advances in laser technology will bring
revolution in dentistry.
Laser is an acronym for light amplification by
stimulated emission of radiation.
It was discovered by Shallow & Towns in 1958.
First working laser was built by Mailman of
Hughes research laboratories in 1960.
HISTORY OF LASERS IN DENTISTRY:
Vain used a ruby laser & reported extensive deep
destruction of carious tissue along with
melting of dentin.
Paghdiwala[U.S.A] in 1988,first time tested the
ability of Er:yag laser on dental hard tissue.
In 1997,Er:yag laser was cleared for marketing by
Food & drug administration of U.S.A.
There are 3 main parts of laser delivery system.
(1).LASING OR ACTIVE MEDIUM
•It is the material which is capable of absorbing
the energy produced by the external source
through subatomic configuration of its
component molecules & subsequently giving the
excess energy as photons of light.
•It can be solid, liquid or gas.
(2).ENERGY OR PUMPING SOURCE
•It is used to excite or pump the atoms in
lasing medium to their higher energy levels
that are essential for laser production.
•It can be electrical,thermal,chemical or
(3).OPTICAL OR RESONATING CHAMBER
•The lasing medium is located within the
•It is a cylindrical structure with fully
reflecting mirror on one side & partially
reflecting mirror on other side--parallel
to each other.
•This arrangement allows reflection of photons
of light, back & across the chamber.
•It will result in production of intense photo
resonance within the medium.
2 categories of lasers are used in medicine & dentistry
- Longer wavelength
- Cuts the tissue by ablation.
- Used for tooth & bone applications.
(2).SOFT LASERS OR LOW LEVEL LASERS
- Low energy wavelengths
- Cuts tissues by coagulation,vapourisation & carbonisation.
- They are believed to stimulate circulation
& cellular activity & causes various effects
such as anti-inflammatory,vascular,muscle
relaxant,analgesia & tissue healing.
There are many types of lasers used in
dentistry, depending upon their active medium
- WAVELENGTH: 10.6um
- USES: SOFT TISSUES , DENTIN DESENSITIZATION
- WAVELENGTH: 488,514.5um
- USES: CURING , SOFT TISSUE DESENSITIZATION
• Ablation of tissues by vapourisationPHOTO-
• Bio-stimulation by stimulated ATP
• Dehydration,burning & carbonization.PHOTO-
Proteins begin to
DIAGNOSIS OF DENTAL CARIES
(A).INFRARED LASER FLUORESCENCE
- Diagnodent is an instrument, recently designed to
facilitate the detection of dental caries.
- Used for detection of caries on occlusal & smooth
(B).LASER INDUCED FLUORESCENCE
- Kutsch in 1992,illuminated carious & non carious tissue
with argon laser along with dark field photography.
- He reported that while illuminating, carious lesion
has clinical appearance of dark,fiery,orange-
CAVITY PREPARATION WITH LASER
- NUMBER OF STUDIES HAVE BEEN PERFORMED FOR THE
USE OF Er:yag LASER FOR CAVITY PREPARATION.
- Results of studies says that little or no noticeable pulp
reaction is produced while preparing the cavity with
- It is safe & can be used for cavity preparation.
Thermal energy absorption by
Water vapourisation & ablation
Carious lesions have more water
content & hence greater effect.
A.)minimises patient fear of the drill.
B.)no irritating sound like traditional drills.
C.)the cavity with laser preparation appears
open,patent,fresh & devoid of all debris.
D.)mono-infection with Enterococcus faecalis is
avoided - hence sterile cavity.
E.)melts the dentin & blocks the tubules,thus
hydrodynamic theory of dentin sensitivity is
PREVENTION OF DENTAL CARIES WITH
Laser can be used for prevention of dental caries.
Different types of lasers increases the resistance to dental
caries by reducing the rate of demineralization of substance
of enamel & dentin.
Argon laser alters the surface characteristics of enamel to
make it caries resistant.
MECHANISM OF ACTION
Carbonate is lost from carbonated appetite mineral of
tooth during laser irradiation
Pulsed co2 laser irradiation interacts with the
phosphate group in dental materials
It gets preferentially absorbed & transformed
efficiently to heat
Carbonated hydroxyapetite in the surface & in the
immediate subsurface of enamel is heated at temp.
greater than 400`c
Carbonate is decomposed, leaving behind the a
hydroxyapetite like mineral that is less soluble
BLEACHING WITH LASERS
- Power bleaching is the term used for accelerated
in-office tooth whitening procedures, using laser or
Xenon plasma arc-curing light.
(A). ARGON LASER
- A true laser light is delivered to chemical agent.
- The action is to stimulate crystals in the chemical.
- No thermal effect, so less dehydration of enamel.
- The treatment time is 10sec. per application per tooth.
It is the advantageous for clinician & patient.
(B). DIODE LASER
- A true laser light produced from a solid state
- It is ultra fast, taking 3 to 5 sec. to activate
- This type of lasers produce no heat.
PHOTOPOLYMERIZATION OF COMPOSITE RESIN
- ARGON LASERS ARE USED FOR THIS PURPOSE.
- FOR POLYMERIZATION OF CAMPHORQUINONE
ACTIVATED COMPOSITE RESIN,THE ARGON LASER
~ THE DEPTH OF CURE
~ THE DIAMETRIC TENSILE STRENGTH
~ ADHESIVE BOND STRENGTH
~ DEGREE OF POLYMERIZATION OF
~ Acid solubility of surrounding enamel
Decreases the time of activation
(1).Minimal damage to surrounding tissues.
(2).Haemostatic effect by sealing blood vessels.
(3).Reduction of postoperative inflammation &
(4).Little postoperative scarring.
(5).Reduction in postoperative pain sensation
since nerve endings are blocked.
(6).Dressing & suturing is not required for
(7).Operating time is reduced.
(8).Sterilization of wound due to reduction in
in amount of microorg. exposed to laser
(10).Excellent wound healing.
(11).Laser exposure to tooth enamel causes
reduction in caries activity.
(12).Patient becomes free
of fear & anxiety.
medication is required
like antibiotics or pain-
(1).Laser beam could injure the patient or operator
By direct beam or reflected light, causing retinal
(2).It available only at
big hospital &
person is needed.
As the research on
use of laser in
dentistry is giving
lasers are getting
Special thanks goes to:
a.) Dr. Soumen Pal
b.) Mr.Abhisek Chatterjee
c.) Mr.Nurul Hasan Mollah