Scanning electron microscopic and energy dispersive spectrometric investigations on the effect of XeCl excimer laser on human dentin with smear layer

Abstract

The purpose of this study was to study the effect of XeCl excimer laser on smear layer covered dentine of extracted human teeth. Twenty-four freshly extracted human molar teeth were collected and randomly divided into one control group and three experimental groups of six teeth each (groups A-D). The teeth in the experimental groups were irradiated with XeCl 308-nm excimer laser at a fluence of 0.4 J cm-2 and a constant pulse repetition rate of 25 Hz. Group A was used as the control, while groups B, C and D were irradiated at different exposure times of 3, 5 and 7 s, respectively. Subsequently these teeth specimens were subjected to scanning electron microscopic (SEM) examination and energy dispersive X-ray (EDX) spectrometric analysis. The SEM examination revealed melting of the smear layer covered dentin to conceal the underlying dentinal tubules. At a longer exposure time (7 s), dentin melted to form large grains and this resulted in non-uniform closure of underlying dentinal tubules. Under the conditions of this study, it is concluded that the pulsed XeCl 308-nm excimer laser at a fluence of 0.4 J cm-2, with an exposure time of 5 s uniformly occluded exposed smear layer covered dentine with no conspicuous variation in chemical structure.

Ultrasonically Activated Irrigation to Remove Calcium Hydroxide from Apical Third of Human Root Canal System: A Systematic Review of In Vitro Studies

“…Scanning electron microscopic studies were also excluded even if they assessed the apical third. It is impossible to distinguish Ca(OH) 2 remnants from the smear layer or dentin debris because energydispersive X-ray spectroscopy analysis shows Ca ++ in both cases (36)(37)(38). For these reasons, 3 studies were excluded even though they assessed the apical third of the root canal (39)(40)(41).…”

Physico-chemical changes of human enamel irradiated with ArF excimer laser

“…Several clinical applications were therefore suggested using the UV lasers in dentistry, and in a variety of medical fields including dermatology, cardiology, ophthalmology, and orthopedics [13][14][15][16][17][18][19][20][21][22][23][24]. These lasers can selectively ablate the organic components of dental hard tissues; the depth, pattern, and surface morphology of the irradiated region can be controlled by the fluence, the number of pulses and the shape of the beam spot [25][26][27][28][29][30][31][32][33]. However, little is known about the physico-chemical changes taking place in the enamel tissue as a result of such irradiation [27,32,33].…”

“…These lasers can selectively ablate the organic components of dental hard tissues; the depth, pattern, and surface morphology of the irradiated region can be controlled by the fluence, the number of pulses and the shape of the beam spot [25][26][27][28][29][30][31][32][33]. However, little is known about the physico-chemical changes taking place in the enamel tissue as a result of such irradiation [27,32,33].…”