LASERS USED IN OPERATIVE DENTISTRY GUIDED BY: Prof. H.D.Adhikary Dept. of Conservative Dentistry Dr.R.Ahmed Dental College & Hospital
CONTENTS Introduction History of lasers Components of lasers Types of lasers Application of lasers in operative dentistry Summary
INTRODUCTION Dentistry has advanced a lot. Among various advances, one which have good scope of improvement is the use oflasersin dentistry. Recent advances in laser technology will bring revolution in dentistry. Laser is an acronym forlightamplification by stimulatedemission ofradiation.
DISCOVERY OF LASERS: It was discovered by Shallow & Towns in 1958. First working laser was built by Mailman of Hughesresearch 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.
COMPONENTS OF LASER 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
optical. (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.
TYPES OF LASERS 2 categories of lasers are used in medicine & dentistry (1).HARD LESARS -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 (1).CARBONDIOXIDE LASER - WAVELENGTH:10.6um - USES: SOFT TISSUES , DENTIN DESENSITIZATION (2).ARGON LASERS - WAVELENGTH:488,514.5um - USES: CURING , SOFT TISSUE DESENSITIZATION
Effects on tissues on certain temperatures 60` 100` 200`
APPLICATION OF LASERS IN OPERATIVEDENTISTRY DIAGNOSIS OF DENTAL CARIES (A).INFRARED LASER FLUORESCENCE [DIAGNODENT] - Diagnodent is an instrument, recently designed to facilitate the detection of dental caries. - Used for detection of caries on occlusal & smooth surface.
(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- red colour.
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 Er:yag laser. - It is safe & can be used for cavity preparation.
ADDITIONAL BENEFITS 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 Enterococcusfaecalis is avoided - hence sterile cavity. E.)melts the dentin & blocks the tubules,thus hydrodynamic theory of dentin sensitivity is ruled out.
PREVENTION OF DENTAL CARIES WITH LASERS 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 hydroxyapetitelike 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 source. - It is ultra fast, taking 3 to 5 sec. to activate bleaching agent. - This type of lasers produce no heat.
PHOTOPOLYMERIZATION OF COMPOSITE RESIN WITH LASER - ARGON LASERS ARE USED FOR THIS PURPOSE. - FOR POLYMERIZATION OF CAMPHORQUINONE ACTIVATED COMPOSITE RESIN,THE ARGON LASER INCREASES; ~ THE DEPTH OF CURE ~ THE DIAMETRIC TENSILE STRENGTH ~ ADHESIVE BOND STRENGTH ~ DEGREE OF POLYMERIZATION OF MATERIELS.
REDUCES; ~ Acid solubility of surrounding enamel Decreases the time of activation Significantly.
ADVANTAGES OF LASERS (1).Minimal damage to surrounding tissues. (2).Haemostatic effect by sealing blood vessels. (3).Reduction of postoperative inflammation & edema. (4).Little postoperative scarring.
(5).Reduction in postoperative pain sensation since nerve endings are blocked. (6).Dressing & suturing is not required for wound closer. (7).Operating time is reduced. (8).Sterilization of wound due to reduction in in amount of microorg. exposed to laser irradiation. (10).Excellentwound healing. (11).Laser exposure to tooth enamel causes reduction in caries activity.
(12).Patient becomes free of fear & anxiety. (13).Advantageous for medically compromised patients,since no medication is required like antibiotics or pain-killers.
DISADVANTAGES OF LASERS (1).Laser beam could injure the patient or operator By direct beam or reflected light, causing retinal burns.
(2).It available only at big hospital & treatment is very expensive. (3).Specially trained person is needed.
SUMMARY As the research on use of laser in dentistry isgiving bright results, lasers are getting more & more famous among dentists.
Special thanks goes to: a.) Dr. Soumen Pal b.) Mr.AbhisekChatterjee c.) Mr.NurulHasanMollah d.)Mr.Tousif Ahmed