Gallium diffusion in human root dentin: Quantitative measurements by pulsed Nd:YAG laser ablation combined with an inductively coupled plasma mass spectrometer

A. M. Ghazi, S. Shuttleworth, S. J. Angulo, D. H. Pashley

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Objective: The purpose of this work was to determine if gallium nitrate placed in human root canals would diffuse across root dentin and reach concentrations high enough to inhibit osteoclasts (~10-4 M). Background Data: External root resorption by osteoclasts is a common sequela of dental trauma. If not detected and treated, it can lead to the loss of a tooth. Gallium has recently been reported to inhibit osteoclastic resorption in vitro. Methods: Roots were cleaned and shaped using standard endodontic procedures and the tips sealed with cyanoacrylate cement. The root canal space was filled with an aqueous solution of 1.0 M gallium nitrate chelated with 1.0 M sodium citrate buffer (pH 7.2). The roots were then sectioned longitudinally into two equal halves. Each half was fixed to a translation stage that moved at a constant rate beneath a frequency-quadrupled Nd-YAG laser (266 nm) laser that was used to sample the concentration of 43Ca, 69Ga, and 71Ga by laser ablation across the thickness of root dentin to the periodontal surface. The plume of ablated dentin was swept into an inductively heated plasma chamber by argon gas and hence into a mass spectrometer. Results: Quantitative analyses of the distribution of gallium showed it was highest adjacent to the root canal space and fell as more peripheral sites were sampled but then rose slightly at the external boundary of the root which is covered with a thin layer of atubular cementum. Conclusions: Even the lowest concentrations of gallium found in peripheral root dentin exceeded the 10-4 M concentration required to inhibit osteoclastic activity. This simple endodontic treatment should undergo clinical trials to determine its efficacy in vivo. The laser ablation, inductively coupled mass spectrometry method is a powerful analytic tool for measuring spatial distribution of materials in mineralized tissues.

Original languageEnglish (US)
Pages (from-to)173-183
Number of pages11
JournalJournal of Clinical Laser Medicine and Surgery
Volume18
Issue number4
StatePublished - Aug 1 2000

Fingerprint

Gallium
Solid-State Lasers
Laser Therapy
Inductively coupled plasma
Mass spectrometers
gallium nitrate
Laser ablation
Dentin
Dental Pulp Cavity
Canals
Endodontics
Osteoclasts
Nitrates
Root Resorption
Cyanoacrylates
Dental Cementum
Tooth Loss
Argon
Lasers
Mass Spectrometry

ASJC Scopus subject areas

  • Surgery
  • Biomedical Engineering

Cite this

Gallium diffusion in human root dentin : Quantitative measurements by pulsed Nd:YAG laser ablation combined with an inductively coupled plasma mass spectrometer. / Ghazi, A. M.; Shuttleworth, S.; Angulo, S. J.; Pashley, D. H.

In: Journal of Clinical Laser Medicine and Surgery, Vol. 18, No. 4, 01.08.2000, p. 173-183.

Research output: Contribution to journalArticle

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