Analysis of peripheral thermal damage during the rapid ablation of dentin and bone using a λ= 9.3-μm TEA CO 2 Laser

Paul W. Bell, Kenneth Fan, Robert S. Jones, Daniel Fried

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

TEA CO 2 lasers tuned to the strong mineral absorption of hydroxyapatite at λ=9-μm are ideally suited for the efficient ablation of dental hard tissues if the laser-pulse duration is stretched to greater than 10-μs to avoid plasma formation. CO 2 lasers are capable of operating at high repetition rates for the rapid removal of dentin and bone. The purpose of this study was to test the hypothesis that stretched λ=9.3-μm TEA CO 2 laser pulses can produce lateral incisions in dentin and bone for dental restorations and implants at repetition rates as high as 400-Hz without peripheral thermal damage. A high repetition rate, 0-500-Hz, λ=9.3-μm TEA CO 2 laser with pulse durations of 10-20-μs was used to make incisions in human dentin and porcine alveolar bone with a computer controlled scanning stage and water spray at varying irradiation intensities. The single pulse ablation rates were determined for incident fluence ranging from 1-150-J/cm 2. Lateral incisions 2-3-mm in length were produced in the 2-mm thick sections. Following irradiation, transverse cross-sections were examined using polarized light microscopy (PLM) and Fourier transform infrared spectro-microscopy (SR-FTIR) at the Advanced Light Source at Lawrence Berkeley National Laboratory. The single-pulse ablation rates approached 40-μm per pulse for the stretched TEA laser pulses in dentin and bone. All incisions with and without water spray yielded thermal damage zones of less than 22-μm. Thermal damage zones with water spray were less than 14-μm, even at repetition rates of 400-Hz and SR-FTIR showed no spectral changes around the periphery of the incisions. CO 2 laser pulses at λ=9.3-μm of 10-20-μs duration are well suited for the precise removal of dentin and bone for dental restorations and implants at high repetition rates without peripheral thermal damage.

Original languageEnglish (US)
Title of host publicationLasers in Dentistry XII
DOIs
StatePublished - Jun 30 2006
EventLasers in Dentristry XII - San Jose, CA, United States
Duration: Jan 22 2006Jan 22 2006

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume6137
ISSN (Print)1605-7422

Conference

ConferenceLasers in Dentristry XII
Country/TerritoryUnited States
CitySan Jose, CA
Period1/22/061/22/06

Keywords

  • Bone
  • CO laser
  • Dentin
  • Hard tissue ablation
  • Laser dentistry
  • TEA laser
  • Water-spray

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