The effect of an Nd–YAG pulsed laser on the cleaning of the root canal and the formation of a fused apical plug

Abstract

A Neodymium-yttrium aluminium garnet (Nd-YAG) pulsed laser was used in vitro to determine whether various laser energy levels from 0.75 W to 1.7 W at 15 pulses s(-1) (pps) were able to (i) remove debris from the walls of prepared root canals (ii) remove pulpal tissue from unprepared canals and (iii) create a fused apical plug from dentine chips, hydroxyapatite (HAP) or low-fusing dental porcelain. Single-rooted teeth were sectioned at the amelocemental junction and the crowns discarded. The root canals of 50 teeth were prepared chemomechanically and allocated to four groups of 10 teeth for laser treatment. One group was left unlased as a control. After lasing, the teeth were split longitudinally, stained and examined for residual debris. Results showed that there was no statistically significant difference between the groups (P<0.05). A further 20 teeth were not prepared and lased in the coronal one-third of the root canal at different energy levels; five teeth were not lased. The teeth were split and examined as previously. The results showed that lasing cleaned the coronal part of the root canal almost completely of pulpal tissue. In the final part of the study laser energy was applied to dentine chips, HAP and low-fusing porcelain in an attempt to produce a fused apical plug. The laser was unable to melt the dentine chips but some hardening of HAP occurred when combined with blue food-colouring, with or without glycerine, at energy levels of 1.0 W, at 15 pps for 30 s. Superficial hardening of low-fusing porcelain occurred at 1.0 W, 15 pps for 30 s.

Laser induced biostimulation: A possible healing prospect in endo-perio lesion

“…Although scaling and root planning remain the initial treatment modalities in periodontal therapy, the use of a softtissue diode laser can be considered as an efficacious adjunct to conventional periodontal therapy. The role of laser radiation in disinfection of the root canal has been demonstrated by Shetty et al, [11] Saunders et al [12] Yamazaki et al, [13] and Takeda et al [14] The use of a diode laser in soft-tissue procedures are advocated because it helps in bacterial decontamination, promotes reestablishment of connective tissue attachment and are less invasive nature, which reduces post-operative swelling. [15,16] CONCLUSION Based on the above study it can be concluded that endoperio lesions always possess a challenge to the clinician for correct diagnosis and treatment planning.…”

Effects of Nd:YAG Laser Irradiation on Root Canal Dentin Wall: A Scanning Electron Microscopic Study

“…Saunders et al 9 and Khan et al 3 believe that an advantage Nd:YAG laser is the fact that the opic fiber to be flexible, that allows an easy penetration in the root canal, also in areas with difficult access as the apical third. However, it was verified in the present study that laser action inside the root canal is limited.…”

“…On the other hand, Saunders et al, 9 in 1995, verified that smear layer and debris removal from root canal after Nd:YAG laser application was not effective when compared with smear layer removal promoted by conventional preparation. According to this author, it was not possible to observe where there was the removal of smear layer and where there was not, because both situation presented similar aspects in the scanning electron microscopic.…”

“…9 To improve fiber tip contact with dentin walls, circular movements are used promoting better laser light incidences. 9 However, the extension and diameter of root canal can difficult direct contact of fiber tip with the dentin walls.…”

Assessment of Morphological Changes and Permeability of Apical Dentin Surfaces Induced by Nd:YAG Laser Irradiation through Retrograde Cavity Surfaces

“…Dederich et al 1 suggest the Nd: YAG laser irradiation reduces the permeability of the dentin wall in root canal due to the melting of the tissue. Marques et al 5 showed the pulsed Nd:YAG laser has the ability of melting the dentin wall in a root canal using an output of 1 to 3 W. On the other hand, Saunders et al 6 had reported that pulsed Nd:YAG laser irradiation with a power of 0.75 to 1.7 W did not melt the wall of the root canal and failed to remove the debris.…”