title: A survey of the efficiency of visible light curing units.
abstract: OBJECTIVE
  The purpose of this study was to survey the efficiency of visible light curing units in dental practices across Australia.
  
  
  METHODS
  Survey forms were distributed to representatives of 3M Health Care to complete when visiting dentists in their working areas. The information collected included the type and age of the unit, curing times used, history of maintenance, replacement of components, and the light intensity reading.
  
  
  RESULTS
  Of the 214 light curing units surveyed, approximately 27% recorded a light intensity of 200 mW cm-2 or less, a level regarded as inadequate to cure a 2-mm thick increment of composite resin. An additional 26% registered an output of between 201 and 399 mW m-2. This level would be considered acceptable with additional curing time; however, 44% of practitioners were curing for 20 s or less. A negative correlation was found between the age of the unit and the intensity recorded. Nearly 50% of respondents had never checked the light output of their unit.
  
  
  CONCLUSIONS
  The results indicate that just over one-half of the light curing units surveyed were not functioning satisfactorily. An obvious reduction in intensity was noted with the older units. There is a substantial lack of awareness among dentists of the need for maintenance and regular checking of the light intensity of these units.
authors.affiliation: Faculty of Dentistry, University of Sydney, Surry Hills, Australia. femartin@dentistry.usyd.edu.au
authors.forename: F E
authors.initials: FE
authors.lastname: Martin
mesh_terms: D000704:Analysis of Variance; D001315:Australia; D016009:Chi-Square Distribution; D003188:Composite Resins / Q000737:chemistry; D003748:Dental Equipment; D004868:Equipment Failure; D008027:Light; D016014:Linear Models; D008283:Maintenance; D011108:Polymers / Q000737:chemistry; D011874:Radiometry; D011795:Surveys and Questionnaires; D013674:Technology, Dental / Q000295:instrumentation*
chemical_list: D003188:Composite Resins; D011108:Polymers