Thermal changes and cure depths associated with a high intensity light activation unit

Dominic Stewardson, Adrian Shortall, Edward Harrington, Philip Lumley

Research output: Contribution to journalArticle

29 Citations (Scopus)


Objectives. The objectives of this study were to evaluate the thermal emission and curing characteristics of a high intensity halogen light (Astralis 10-Ivoclar Vivadent, Schaan. Leichtenstein) alone and on curing a conventional and a fast-curing micro-hybrid composite. Methods. A bead thermistor was placed in the base of a standard model cavity. The cavity was irradiated using the light unit whilst empty, and when fitted with either composite. Temperature rises were recorded using the tight in four different output modes. Further samples were prepared to assess depth of cure via a digital penetrometer, tight transmission using a computer-based radiometer, and microhardness with a Wallace hardness tester. Results. Mean peak temperature rises recorded during polymerisation of the composites ranged from 6.9 degreesC for the product InTen-S cured with the Adhesive programme (Adh) to 11.0 degreesC for the product Tetric Ceram HB cured with the High Power (HI P) programme. A significantly greater depth of cure was obtained for InTen-S in tine with the greater tight transmission obtained for this material. Discussion. The very high thermal emission characteristics reported in a recently published investigation for this light unit were not confirmed. Conclusions. As the extent of thermal trauma that can be tolerated by the dental pulp is unknown consideration should be given to the choice of tight activation unit and curing programme when polymerising Light activated resin based restorations in deep cavities close to the pulp. (C) 2004 Published by Elsevier Ltd.
Original languageEnglish
Pages (from-to)643-651
Number of pages9
JournalJournal of Dentistry
Issue number(8)
Publication statusPublished - 1 Jan 2004


  • visible
  • composite resins
  • hardness tests
  • light
  • temperature


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