Wavelength and average power density dependency of the surface modification of root dentin using an MIR-FEL
✍ Scribed by Manabu Heya; Shu Sano; Nobuhiko Takagi; Yuko Fukami; Kunio Awazu
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 514 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0196-8092
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✦ Synopsis
Abstract
Background and Objectives
Surface modification of root dentin by mid‐infrared (MIR) pulsed‐laser irradiation is one of the candidates for a novel, non‐invasive treatment to prevent root surface caries. To modify root dentin effectively and non‐invasively it is essential to estimate quantitatively and qualitatively the laser parameters, such as the wavelength and power density, required for surface modification. The key aspect is to bring about effective surface modification of the root dentin while minimizing the unwanted removal of the underlying dentin.
Study Design/Materials and Methods
Using a tunable, MIR Free Electron Laser with λ = 8.8–10.6 μm, we have investigated macroscopically the extent of the surface modification (morphological and chemical changes) of root dentin. We have obtained experimental results related to the ablation depth, the MIR absorption spectrum, and the elemental chemical composition.
Results
The observations showed that the surface modification of root dentin was inclined toward well‐recrystallized HAp‐like material, leading to an increase in the acid resistance and dentinal tubule sealing. The laser parameters, at which efficient surface modification without enhanced ablation occurred, were estimated to be approximately in the wavelength region around λ = ∼9.0 or ∼9.7 μm and in the average power density region of ∼10–20 W/cm^2^ (resulting in total energy density and peak power density regions of ∼1–2 kJ/cm^2^ and ∼0.67–1.2 kW/cm^2^).
Conclusions
The surface modification of root dentin strongly depends on the laser parameters applied. We conclude that the optimum wavelengths for laser treatment of root surface caries are λ = ∼9.0 or ∼9.7 μm, corresponding to the absorption peak due to P‐O stretching. Lasers Surg. Med. 32:349–358, 2003. © 2003 Wiley‐Liss, Inc.