title: The effect of infection-control barriers on the light intensity of light-cure units and depth of cure of composite.
abstract: OBJECTIVE
  Dental curing lights are vulnerable to contamination with oral fluids during routine intra-oral use. This controlled study aimed to evaluate whether or not disposable transparent barriers placed over the light-guide tip would affect light output intensity or the subsequent depth of cure of a composite restoration.
  
  
  METHODS
  The impact on light intensity emitted from high-, medium- and low-output light-cure units in the presence of two commercially available disposable infection-control barriers was evaluated against a no-barrier control. Power density measurements from the three intensity light-cure units were recorded with a radiometer, then converted to a digital image using an intra-oral camera and values determined using a commercial computer program. For each curing unit, the measurements were repeated on ten separate occasions with each barrier and the control. Depth of cure was evaluated using a scrape test in a natural tooth model.
  
  
  RESULTS
  At each level of light output, the two disposable barriers produced a significant reduction in the mean power density readings compared to the no-barrier control (P<0.005). The cure sleeve inhibited light output to a greater extent than either the cling film or the control (P<0.005). Only composite restorations light-activated by the high level unit demonstrated a small but significant decrease in the depth of cure compared to the control (P<0.05).
  
  
  CONCLUSIONS
  Placing disposable barriers over the light-guide tip reduced the light intensity from all three curing lights. There was no impact on depth of cure except for the high-output light, where a small decrease in cure depth was noted but this was not considered clinically significant. Disposable barriers can be recommended for use with light-cure lights.
authors.affiliation: Department of Primary Dental Care, GKT Dental Institute, London SE5 9RW, UK. nicholas.hodson@kcl.ac.uk
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Hodson
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Dunne
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Pankhurst
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000528:radiation effects*; D003748:Dental Equipment; D004209:Disposable Equipment; D020724:Elastomers; D004866:Equipment Contamination; D006801:Humans; D019552:Infection Control, Dental / Q000295:instrumentation*; D008027:Light; D008963:Molar; D044367:Phase Transition; D011143:Polyvinyl Chloride; D011482:Protective Devices; D011874:Radiometry; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic
chemical_list: D003188:Composite Resins; D020724:Elastomers; D011143:Polyvinyl Chloride