Naslov
Erbium:YAG and Neodimium:YAG laser in dentistry With consideration on temperature increase in the pulp and periodontal tissue

Autori
Jukić, Silvana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, stručni

Izvornik
Laser in dentistry 2004 / Skalerič, Uroš ; Moritz, Andreas ; Grad, Ladislav - Bled : Alpe Adria Laser Congress, 2004

Skup
Alpe Adria Laser Congress

Mjesto i datum
Bled, Slovenija, 07.05.2004. - 08.05.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Er:Yag laser; Nd:YAG laser; Temperature changes; Restorative dentistry; Endodontics

Sažetak
Erbium itrij-aluminium-garnet (Er:YAG) laser is the only one laser that American Food and Drug administration approved for cavity preparation. Wave length of Er:YAG (2940 nm) correspond to absorption peak of hydroxyapatite and water, so ablation process starts immediately with relatively small amount of energy transformed into the heat. In spite of that, heating of the target tissue is significant and all Erbium lasers are equipped with water cooling. Newer technology of variable square pulse enables the control of pulse duration and its amplitude, as well. This means that shorter pulse reaches faster the high ablation threshold of hard dental tissues and relatively small amount of energy is transformed into heat, in contrast to classic Erbium lasers. The temperature increase was measured in cavum pulpae during cavity preparation in cervical region with Er:YAG laser (Fidelis, Fotona, Slovenia) (Fig 3). The enamel was irradiated with laser beam energy of 400, 360 and 320 mJ in contact mode using a very short pulse (VSP) 100  s in length. Frequency was 15, 12 and 10 Hz, and each irradiation lasted 10 s. Dentine was irradiated with laser beam energy of 340, 280 and 200 mJ, frequency 10, 8 and 5 Hz during 7 s. Water spray (73 psi) was used for cooling of the surrounding tissue. The highest temperature increase in the pulp space was noticed at energy 400mJ/15 Hz (1.99  0.28 C), and the lowest at 320 mJ/10 Hz (0.70  0.18 C). During the dentine irradiation the highest temperature increase was recorded at 340 mJ/10 Hz (1.37  0.42 C), and the lowest at 200 mJ/5 Hz (0.43  0.18 C). Temperature increase in root canal was measured during calculus removal by Er:YAG laser in contact mode. Energy of the laser beam was 200 mJ, frequency 10 Hz, and duration of irradiation was 40 s. The cooling was done by water spray (73 psi). The average temperature increase in root canal was 2.2 &plusmn ; ; 0.4°C. Cooling to the room temperature started during irradiation proces. Nd:YAG laser is used in endodontics for root canal disinfection after instrumentation. Also, it can be use for softening and removal of gutta-percha during retreatment due to heating effect of laser beam. The attention should be taken to avoid overheating of the root surface and consequent external resorption. Measuring of the temperature on root surface during retreatment by Nd:YAG laser (1.5 W/20 Hz) in irradiation cycles of 15 s revealed average temperature increase of 8.29  0.41 C what is cosidered to be inside the safe limits for the periodontal tissue. The time needed for completed of gutta-percha removal was 6.45 &plusmn ; ; 0.49 min.

Izvorni jezik
Engleski

Znanstvena područja
Dentalna medicina

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