title: [A survey of power density of clinical curing-light units used in Changchun].
abstract: OBJECTIVE
  To investigate the power density and other relevant data of clinical curing-light units used in Changchun, and to provide practice recommendations to clinical dentists about maintaining of cuing-light units.
  
  
  METHODS
  Stomatology hospitals, departments of stomatology in general hospitals, and private dental offices in Changchun were randomly selected to participate in the Survey. The investigation analyzed 270 curing-light units. The following data of curing-light units were gathered: brand, type, operation ages, numbers and types of light guide, resin build-ups on light guides, damages of light guides, use frequency, monitor and maintenance of curing lights, and unit numbers/chair numbers.
  
  
  RESULTS
  There were 174 QTH and 96 LED units. The distribution of power density was from 0 to 1702 mW/cm(2). The mean power density was 413.2 mW/cm(2). The power densities of 73 lights were less than 200 mW/cm(2) and could not polymerize resin composites adequately. The mean number of operation age of the light units was 4.74 years. Most of clinical dentists didn't monitor the light-curing units and the situation of build-up from composite resin or damages on light guides was very severe.
  
  
  CONCLUSIONS
  Most of the light-curing units used in Changchun were QTH. Some QTH units degenerate severely and need to be replaced with the new ones. Most of the clinical doctors lack the knowledge of how to properly monitor and maintain the light-curing units.
authors.affiliation: Department of Prosthodontics, School of Stomatology, Jilin University, Changchun, China.
authors.forename: Xin-qing
authors.initials: XQ
authors.lastname: Hao
authors.forename: Meng
authors.initials: M
authors.lastname: Luo
authors.forename: Xin
authors.initials: X
authors.lastname: Leng
authors.forename: Song
authors.initials: S
authors.lastname: Zhu
mesh_terms: D002681:China; D003188:Composite Resins / Q000737:chemistry; D055117:Curing Lights, Dental / Q000145:classification / Q000706:statistics & numerical data; D006219:Halogens; D011791:Quartz; D012666:Semiconductors; D014414:Tungsten
chemical_list: D003188:Composite Resins; D006219:Halogens; D011791:Quartz; D014414:Tungsten