Effects of Nd: YAG lazer irradiation at different parameters on osteoblast cell cultures

Dental lasers had beeen used in dentristry in a wide range of application including surgery, periodontology, endodontics, operative dentistry and orthodontics for more than 30 years. Their fiber optic delivery system of 320 urn made Nd:YAG lasers preferable at root canal sterilization, removing of debris and elimination of Smear layer in addition to other conventional endodontic uses. The aim of this study was to evaluate the effects of Nd:YAG laser usage on alveoler bone at celluler level by using cell culture methods. In this study we used Nd:YAG laser on human osteoblast like cell line Saos-2 in a non-contact mode for 10 seconds with 20-120 mj, 10-30 Hz, and 0.2-3.6 W parameters. He-Ne laser wihch is the guide light of Nd:YAG laser was used in a non- contact mode for 10 seconds. After 7, 14 and 21 day incubation period, cell viability and proliferation was evaluated with MTT method and cellular activity was assessed with ALP and osteocalcin mesuarements. Cellular mineralisation evaluated with ALP and calcium stainings. The results of this study showed that, when the avarage MTT values were compared, there was no statistically diffence between 20mj, 10 Hz, 10 seconds (Group 1), He-Ne (Grup 14) and control group (Group 15) (p>0.05). The differences between all other groups were significant (p<0.05). When ALP activities were compared, there was no statistically diffence between 20mj, 10 Hz, 10 seconds (Group 1) and control group(Group 15). The difference between all other groups were also significant (p<0.05). When avarage MTT absorbance values, ALP and osteocalcin activities were compared, increase in the pulse energy and power output had a negative effect on human osteoblast like cell cultures.It was concluded that; usage of the lowest parameters should be choosen if the pulse energy and power output was appropriate for the suggested theraphy.