Only few years after the discovery of laser investigations were performed to introduce laser technology into dentistry for optical drilling of teeth. Conservative applications for lasers in dentistry are
Caries detection by laser induced fluorescence
Prevention of enamel and dentine caries
Pit and fissure sealants
Bleaching of vital and non-vital teeth
Etching and bonding agents
Curing light activated resins
Diagnosis of Caries by Laser
It is well known that a carious process dissolver removes enamel minerals. Early detection is therefore very important, since it allow preventive approach rather than a restorative one. Laser induced fluorescence is potential technique for the detection of carious process. Scientific studies indicate that argon laser energy will offer diagnostic capabilities when used to illuminate teeth. When illuminated with argon laser light, carious tissue has clinical appearance of dark, fiery, orange red colour. Decalcified areas appear as a dull, opaque, orange colour. To examine a tooth, power out put should be set to the lowest available setting, normally 80nw, continuous wave. Fiber of 300micrometer is selected and this creates a 1140W/cmsquare power density at the tip. The delivery fiber should be placed either lingually to the teeth and observed from the facial aspect or visa versa using a mouth mirror. Fiber should be moved in and out of the contact of teeth and redirection thoroughly to expose and examine the entire clinical crown. Enamel fracture are also apparent during this procedure.
Removal of Caries by Laser
Pulsed YAG laser is used on enamel fissures to remove organic and inorganic debris from pits and fissures without causing pulpal or enamel injury due to the minimal laser energy.
Prevention of Enamel and Dentine Caries by Laser
Lasers increase the resistance to caries by reducing the rate of demineralization of enamel and dentine or by combine effects of laser with fluoride by facilitating the tooth’s uptake of fluoride to improve this result.
Bleaching by Laser
Argon and carbon-dioxide lasers are used in the tooth whitening process.
How Lasers Work In Bleaching
The laser is thought to provide energy to the blending medium to undergo breakdown, providing the oxygen radicals for lightening or oxidizing the stained tooth.
Types of Lasers in Bleaching
The different types of lasers in Bleaching are:
Combination of carbon dioxide and argon laser
Argon laser alone
Carbon dioxide laser alone
It is a process of continuous vaporization and micro explosive due to vaporization of water trapped within the hydroxyapaptite matrix. The degree of surface roughing depends upon the system used and the wavelength of the laser.
Advantages of Laser Etching
Improves bond strength.
Carbon dioxide laser radiation render enamel more resistant to subsurface demineralization and artificial caries
Recurrent caries around restorations placed using laser etching may be reduced.
Laser Doppler Flowmetery
In this pulpal blood flow can be recorded by means of laser Doppler flowmetery by placing probe on buccal surface of teeth and perpendicular to beam reflection during measurement.
Laser is used to block the tubules by reducing sensitivity.
Polymerization of Composite Resins
Visible light has ability to penetrate both composite material and tooth structure to polymerize camphoroquinone activated resins. Argon laser is used to polymerize camphoroquinone composite resins.