Abstract — Laser  technology  was  introduced  in  dentistry   with  a  novel  idea  of  overcoming  some  of  the  problems due  to  traditional  treatment   methods.  After  its  first  use   in 1960s, laser technology has found its place in different  aspects  of  dentistry  field.  The  aim  o f  this  review  is  to   explain laser applications and  compare different types of  lasers along with their adva ntages and disa dvantages.  A   computer based search was  done to study 135 articles in  seven  journals.  Laser  inhe rent  properties  make  it  the   treatment  of  choice  is  some   cases.  Its  main  achievement   is  overcoming  patient  fear  associated  with  conservative   dental treatment. On the downside, cost is a big limiting  factor in its use. Since the disc overy of laser, its research  has  given  different  improv ed  laser types,  specialized  for   different  targets,  like  new   wavelength  bands,  maximum   peak  pulse  energy,  output  power,  minimum  cost  and   maximum  efficiency.  Based  on  its  development  and  its   improved  efficiency,  laser  te chnology  application  may   revolutionize traditional dental treatment methods.
1. INTRODUCTION The  space  time  has  arrived.  It’s  no  longer  that  lasers  are   used in movies only. Interestingly lasers are finding place in  many  aspects  of  life  and  this   includes  dentistry  also.    Laser   dentistry means use of laser technology in field of dentistry  for  purpose  of  diagnosis,  treatment  or  therapy.  The  use  of   laser  in  dentistry field  has  been tremendously  increased  for   the past few years.  Laser dentistry takes opportunity of new  developments  in  dentistry  to  provide  dramatically  better   dental   experiences   which   yield   lesser   side   effects   as    compared to conventional trea tments. The main attraction in  using laser technology is that p atient discomfort and stress is alleviated.  The  first  ever  laser  us ed  in  dentistry  was  during   1960s  [1].    Now  lasers  are  indicated  for  various  uses  in   dentistry  [2].  This  paper  pres ents  an  overview  about  laser   technology  in  dentistry.    It   describes  application  of  laser  in   dentistry, comparison of different types of lasers along with  their  advantages  and  disadvantages.  Section  II  describes   background   detail   about   lasers;   Section   III   describes    application of lasers in dentistry, Section IV mentions about  safety  of  lasers.  Section  V  describes  future  concerns  about   laser and Section V1 is about Conclusion.
EFFECT OF LASER ON TISSUE
When  energy  is  emitted  from  laser  and  it  comes  in  contact   with  tissue,  so  it  can  have  four   different  types  of  responses   and these responses are dependen t on optical properties of   tissue [8].   The  first  response  is  Reflection.  This  means  that  beam  of   laser  is  reflected  back  from  surface  hence  tissue  is  not   affected.  The  reflected  light  can  then  become  diffuse  or   collimate in form of a narrow beam.           The  second  response  is  passage  of  laser  energy  through   tissue,  but  not  effecting  tissue.  The  effect  depends  on  laser   wavelength. The third response is scattering of laser energy.  This  produces  no  useful  effect.   This  is  because  energy  is   changed   into   heat   energy,   so   adjacent   tissue   can   be    damaged. But this is useful in curing of dental materials.     The  fourth  response,  the  desirable  response,  is  absorption   of  laser  energy  by  tissue.  This   absorption  is  dependent  on   characteristics    of    tissue    li ke    water    content,    and    on     wavelength of laser and its mode of emission.
Nd: YAG is solid state laser. It also allows homeostasis  which  is  beneficial  for  clinicians.  The  advantage  is  its   flexibility  of  fiber  delivery  system,  hence  eliminating  the   necessity   for   using   traditional   articulated   arm   delivery    method.  One  of  biggest  disadvan tages  with  this  laser  is  the   deeper  penetration  of  laser  energy  hence  damage  to  tissue   can be more than anticipated [ 17]. It does not remove tooth  enamel  as  efficiently  as  erbium,  Er:  YAG,  Er,  Cr:  YSGG   laser.   Another   systematic   review   was   done   to   analyze    efficacy  of  a  pulsed  ND:YAG  laser  in  treatment  of  patients   with    periodontitis    or    as    an    additional    method    to     conventional therapy of periodontitis. The review concluded  with  no  superior  result  for  Nd:  YAG  laser  as  compared  to   traditional treatment in this case [18].
happens which can be eliminated with LLLT [43]. It is also  useful   in   removing   pain   and   discomfort   in   trigeminal    neuralgia  [44].  If  a  dentist  is  specialized  in  acupuncture,   LLLT will be an easy method of replacing needles in many  cases  for  acupuncture  [45].  Needles  are  always  scary  to   patients, so laser are pref erred in this case. There  is  a  huge  research  work  done  on  developing  new   laser   application   in   dentistry    and   each   year   different    meetings  are  arranged  which  bring  together  this  research   like  international  society  for  lasers  in  dentistry,  academy  of   laser  dentistry,  European  society  for  oral  laser  applications   etc.  So  there  will  be  more  opportunities  for  dentists  to   become  involved  in  these  me etings  and  present  their  work   and ideas.   Laser  technology  is  a  new  idea  in  dentistry.  The  existing   literature  is  a  sufficient  foundation  for  successful  use  of   laser  in  clinical  dentistry  but  mo re  evidence  based  research   is  needed  to  find  out  suitable  parameters.  Laser  provides   safe,  effective  and  virtually  pain-free  dental  practice.  The   indications  for  laser  use  are  continually  expanding  and   ultimately   this   is   benefitting   patient.   Dentists   need   to    become   knowledgeable   about   lasers   so   that   they   can    maximize the application of laser.   A CKNOWLEDGMENT The  authors  would  like  to  thank  Dr  Muneer  Babar,  at   International  Medical  University,  Malaysia,  for  his  useful   suggestions and providing guidance in this work.