Effect of pulse duration of Er: YAG laser on dentin ablation.
The present study examined the effects on dentin ablation efficiency arising from various pulse durations of Er: YAG laser at a fixed energy fluence. Ten flat human dentin disks were prepared and exposed to an Er: YAG laser at 1 pps for three seconds at pulse durations of 100-500 microsec with 150 mJ/pulse (40.0 J/cm x pulse). The depth and diameter of the ablated dentin were measured and the ablation volume was estimated. Irradiated surfaces and cross-sections were observed using a SEM. Depth of the removed dentin increased and the diameter of the spot decreased without a change in the estimated volume at increased pulse durations. SEM observation of the irradiated surfaces revealed that there were no morphological differences when the pulse duration was changed. When the specimens were cross-sectioned, the ablated dentin had a dome shape and there was a dark layer under the irradiated surface.
Nishimoto
Yuki
Y
Cariology and Operative Dentistry Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. neige0128@yahoo.co.jp
Otsuki
Masayuki
M
Yamauti
Monica
M
Eguchi
Testuya
T
Sato
Yasuharu
Y
Foxton
Richard M
RM
Tagami
Junji
J
D003116:Color; D003804:Dentin / Q000601:surgery* / Q000648:ultrastructure; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D016369:Smear Layer; D013997:Time Factors