Ultrastructural changes of human dentin after irradiation by Nd:YAG laser

✍ Scribed by Bor Shiunn Lee; Chun Pin Lin; Feng Huei Lin; Wan Hong Lan

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 311 KB
• Volume: 30
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.10038

✦ Synopsis

Abstract

Background and Objective

The use of Nd:YAG laser has been proposed for endodontic treatment. However, its ability to reduce dentin permeability, which is important for the success of root canal treatment, remains controversial.

Study Design/Materials and Methods

Nd:YAG laser irradiation was performed in pulsed mode on human dentin. The parameters were: pulse energy (100 mJ), rate (10 pps), and total irradiation time (4 seconds). The crystalline phases, electron diffraction patterns, morphology, and microstructure of specimens after laser irradiation were observed by dark‐field emission transmission electron microscope (TEM).

Results

Three ultrastructural zones could be delineated in the dentin: (1) an outer zone with an ordered columnar structure composed of hydroxyapatite and β‐tricalcium phosphate, (2) an intermediate zone composed of an amorphous substance (about 40–70 nm in diameter), and (3) an inner zone of well‐crystallized hydroxyapatite grains. These three zones were free of pores or voids.

Conclusions

Our study demonstrated that laser‐irradiation might be used to reduce dentin permeability. Lasers Surg. Med. 30:246‐252, 2002. © 2002 Wiley‐Liss, Inc.