Permeability of dentine after Nd:YAG laser treatment: an in vitro study

Abstract

The purpose of this investigation was to determine the effects of Nd:YAG laser treatment on the permeability of dentine. Forty dentine discs were prepared by horizontal sectioning through the middle coronal third of freshly extracted non-carious third molars. After the removal of the pulp the discs were finished w^ith 600 grit and divided into three test groups and one control group (« = 10). For the test groups three different laser power settings were chosen: test group A: 3 X 60 sec, 60 mJ; test group B: 3 X 60 sec, 90 mJ; test group C: 3 X 60 sec, 120 mJ. No laser treatment was performed on the control group. In a two-chamber system the filtration rate of dentine tubules from an exactly defined area of the specimens was measured using a radioactive Ringer solution under a pressure of 30 cm H2O.Permeability measurements were carried out three times prior to lasing, three times immediately following laser treatment and six times after the application of phosphoric acid. Analysis of variance showed a significant influence of the Nd:YAG laser treatment on the permeability of dentine (P < 0 001). The mean quotient of non-treated control vs. lased dentine was 2-19 ± 0-86 for the 60 mJ beam, 1-49 ± 0-88 for the 90 mJ beam, and 2 04 ± 217 for the 120 mJ beam. Etching the lased surfaces had a statistically significant influence on the permeability of the dentine only in the 60 mJ group (P < 0 001). The data show that the Nd:YAG laser treatment often increases the permeability of smear layer covered dentine but moderates the increase of permeability after etching the surface with phosphoric acid.

Evaluation of subsurface dentin microhardness after Er: yttrium-aluminum-garnet and Nd: yttrium-aluminum-garnet laser irradiation

“…15 These observations can be related to the increase of hardness demonstrated in this study. 15 These observations can be related to the increase of hardness demonstrated in this study.…”

“…Schaller et al 15 reported that treatment with Nd: YAG would influence dentin permeability leading to an increase in superficial acid resistance.…”

“…[6][7][8][9] The Er: YAG laser treatment can cause chemical alterations on microareas of dentine surface, depending on the time duration of the laser pulse used. 13,14 When used on normal or demineralized dentin the Nd: YAG laser also causes alterations on the mineral content of the dentine surface, 15 principally on the organic components of the dentin specially the collagen. The electromagnetic energy absorbed causes the instant heating of water content that transforms into vapor, causing an increase of pressure that leads to the breaking and falling of hard tissue, in a process know as ablation by microexplosion.…”

Advances in the treatment of root dentine sensitivity: mechanisms and treatment principles

“…A 6-month study by Schwartz et al (122) also compared the desensitizing effects of a Er : YAG (erbium-doped, yttrium, aluminum, and garnet) laser with a Dentin Protector s (Ivoclar Vivadent, Ellwangen, Germany) desensitizing system and reported that the laser treatment was significantly more effective in reducing DH/RDS over the study period than the Dentin Protector s . Further research is, however, required before this technique can be recognized as an acceptable treatment for this condition; indeed, several investigators (124,125) have noted safety concerns that due to the apparent destruction of the dentine surface, lasers such as the neodymium-yttrium, aluminum garnet (Nd-YAG) at moderate or therapeutic power levels may be inappropriate for the treatment of DH/RDS. Recently, a light-cured resin-based sealer was evaluated following flap surgery and was observed to reduce RDS over a 30-day period (38).…”

Efeito de agentes anti-hiperestésicos à base de oxalato de potássio na permeabilidade da dentina humana. Estudo In vitro.

“…Os procedimentos adesivos agem oclusivamente pela impregnação das resinas fluidas 31,49,50,69,100,101,104,152,153,162,219,251,254,271,281,286 , ou dos primers 49,51,104,240,254,271 e, ainda, das restaurações com resinas compostas 67,210,211 e com cimento de ionômero de vidro 23,40,223,45 . A luz laser também é capaz de tratar a dentina hiperestésica através da deposição de partículas 74,117,136,147,151,199,230,273,274,287 .…”