<title>Effects of the Nd:YAG laser on amalgam dental restorative material: a preliminary study</title>

Abstract

The Nd:YAG laser has been marketed as an instrument for use on both hard and soft dental tissues. Its potential for use on hard tissues is limited but it may be the instrument of choice for use in certain soft tissue procedures. The aim of this study was to examine the effects of the Nd:YAG laser on amalgam restorations which frequently occur on tooth surfaces adjacent to areas of soft tissue which may be subjected to the laser. The amalgam used was Tytin. The laser firing was controlled by a computer and a constant repetition rate of 40 Hz was used. Energy per pulse was altered as follows, 30 mJ, 40 mJ. 60 mJ, 80 mJ. 120 mJ and 140 mJ. Exposure times of 0.05 sec (2 pulses). 0. 125 sec (5 pulses), 0.25 sec (10 pulses). 0.5 sec (20 pulses). 1 sec (40 pulses). 2 sec (80 pulses). 3 sec (120 pulses). 4 sec (160 pulses), and 5 sec (200 pulses) were used. The width of defect was measured using a Nikon measurescope with lOx magnification and it was established that the damage threshold lies between 0. 125 sec (5 pulses) and 0.25 sec (10 pulses) for 30 mJ per pulse. The data was analyzed using a one way ANOVA statistical test. There was a significant (p<O.OO1) correlation between the width of the defect and energy per pulse setting as well as exposure time. The findings indicate that amalgam restorations are prone to damage from inadvertent laser exposure and clinicians must take measures to protect such restorations during lasing of soft tissues.

Er:YAG lazer uygulamasının Cr-Co alaşımı ve polimetil metakrilat arasındaki makaslama bağlantı kuvveti üzerine etkisi

“…Madani et al (Madani et al 2013) investigated the effect of Nd-YAG laser irradiation to alloy surface and found no significant difference on shear bond strength between resin cement and alloy. Er:YAG laser system, with or without water, can ablate restorative materials, and the presence of water does not decrease the efficiency of ablation, though it prevents temperature rise (Cernavin et al 1999). The ablation process and the formation of crater-like scratches probably achieves micro mechanic retention and it causes, increase the bonding values.…”

Effect of the lasers used in periodontal therapy on the surfaces of restorative materials

“…Since GIC contains 20–50% percent water in its set form, and since Erbium lasers target the water molecules in their irradiation area GIC is likely more susceptible to surface defects from Er,Cr:YSGG lasers than from other types. Earlier studies have tried different types of laser in various modes and in different power options to expose this effect (Mazouri and Walsh, ; Cernavin and Hogan, ; Kilinc et al ., ; Hatipoglu and Barutcigil, ). Er,Cr:YSGG lasers showed a significant effect on GIC in terms of surface roughness and left deep traces in the SEM and AFM images.…”

“…In the examination of amalgam samples, the results of the surface roughness test, which were verified by SEM and AFM images, revealed that neither the Er,Cr:YSGG laser nor the diode laser left a noticeable trace on the surface. Studies that investigated the effects of different lasers on AM reported that lasers cause differently shaped defects in amalgam (Cernavin and Hogan, ; Kilinc et al ., ). Kilinc et al .…”

“…The present study obtained similar outcomes. However, Cernavin and Hogan () stated that pits and other defects increase plaque retention, resulting in increased risk of amalgam corrosion, no matter how small the damage to the AM is. It has been reported that mercury vapor, which may occur due to contact between the laser and the AM surface, should be considered in such situations, and appropriate suctioning should be performed.…”

Adaptivity for finite volume on unstructured triangular meshes: a study of thermal injury in teeth

“…A computer simulation was carried out applying the laser beam normal to location P 1 (Figure 4(a)). An initial time step of 10 −6 s was selected and the simulation was carried out until the final time of 5 s, which corresponds to a typical laser treatment time [22]. The target relative error was 5%.…”