Effect of argon laser irradiation on instrumented root canal walls

The objective of the study was to examine whether argon laser has a property to remove debris and smear layer from root canal walls. Twelve endodontically treated human maxillary molar teeth with three root canals were divided into two groups of six teeth. The first group was left unlased as a control; in the second group the root canals were irradiated by argon laser (laser parameters were set at l W and pulse duration and pulse frequency fixed at 0.05 s and 5 Hz). After the usual root canal preparation and lasing had been carried out, the teeth were decoronatcd, bisected longitudinally, observed \vith a scanning electron microscope and evaluated as to how clean the surfaces of root canal walls were. In most cases control teeth presented surfaces with debris covering the root canals, obscuring the dentinal tubules. Only 1 of 18 specimens was free of debris. In the lased group, root canal surfaces free of debris and vaporized pulpal tissue remnants were observed in 13 of 18 specimens. The results showed significant statistical differences between the control group and the lased groups (/><0.001). These results suggested that argon laser irradiation has an efficient cleaning effect on instrumented root canal surfaces. © Munksgaard, 1998.link_to_subscribed_fulltex

Effects of CO 2 laser in treatment of cervical dentinal hypersensitivity

The effectiveness of CO 2 laser therapy in the reduction and elimination of dentinal hypersensitivity in vivo and its thermal effects on tooth surfaces in vitro were investigated. Twenty-three patients with 91 sensitive teeth participated in this study and were followed for 3 months. The parameters used with CO 2 laser were 1 W in a continuous wave mode and irradiation time ranging from 5 to 10 s. Hypersensitivity was assessed by thermal stimulus (a blast of air from a dental syringe). Thermal effects were measured by thermography using 10 extracted human teeth. After laser treatment, all patients were immediately free from sensitive pain. Over 3 months, the CO 2 laser treatment reduced dentinal hypersensitivity to air stimulus by 50%. All teeth remained vital with no adverse effects. Thermography revealed no temperature increase on irradiated tooth surfaces subjected to water coolant. These results show that the CO 2 laser is useful in the treatment of cervical dentinal hypersensitivity without thermal damage to pulp. Copyright © 1998 by The American Association of Endodontists.link_to_subscribed_fulltex