title: A randomized double blinded study to assess the efficacy of a laser-guided collimator on dental radiography training.
abstract: OBJECTIVE
  To assess the effect of a laser-guided collimator in intraoral radiography training.
  
  
  METHODS
  A custom-made collimator with four red laser diodes on each corner on the rim of an aluminium alloy cubic housing was fabricated. The laser used low power diodes, which are classified as laser-safe by the United States Food and Drug Administration (FDA). When activated, the effective dimensions of the laser beams were 4 cm x 4.5 cm. Eighteen dental hygiene students were randomized into test and control groups. The Laser group used a rectangular collimator with the laser device, while the Non-laser group used a conventional rectangular collimator. Each group attended nine intraoral radiography training sessions. All radiographs were assessed and were classified into three categories: Excellent, Acceptable and Repeat, by a masked academic staff member. Reasons for repeats were marked. Statistical comparisons between the two groups were made.
  
  
  RESULTS
  A total of 2334 radiographs were made. Conecut was more common on bitewings than periapicals. The Laser group produced fewer conecuts than the Non-laser group. The Laser group produced more excellent radiographs with fewer repeats than the Non-laser group, but there was not a significant difference.
  
  
  CONCLUSIONS
  The laser-guided collimator helped the students to produce fewer repeats in a shorter period of time. It was an effective training aid.
authors.affiliation: Oral Radiology, The Prince Philip Dental Hospital, 34 Hospital Road, Sai Ying Pun, Hong Kong.
authors.forename: A C M
authors.initials: AC
authors.lastname: Chau
authors.forename: T K L
authors.initials: TK
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Wong
mesh_terms: D003756:Dental Hygienists / Q000193:education; D004311:Double-Blind Method; D005374:Filtration / Q000295:instrumentation; D006801:Humans; D007834:Lasers; D016300:Radiography, Bitewing / Q000295:instrumentation*; D011871:Radiology / Q000193:education*