Effect of Different Irradiation Times on the Occlusion of Dentinal Tubules When Using a Nd:YAG Laser: An in Vitro SEM Study

Xiaoyu Guo¹, Jinhua Yu¹, Roger J. Smales², Huifen Chen³, Haiyan Si³, Younong Wu^1*

¹Department of Endodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
²School of Dentistry, Faculty of Health Sciences, The University of Adelaide, Adelaide, Australia.
³Institute of Stomatology, Nanjing Medical University, Nanjing, China.

DOI: 10.4236/ojst.2015.53011                

Abstract

Objective: To evaluate the effect of different irradiation times on the occlusion of dentinal tubules when using Nd:YAG laser. Background data: Dentin hypersensitivity is a frequent problem that has limited treatment success despite many chemical and physical therapies. Methods: Four coronal dentin disks 2 mm thick were cut with a low-speed diamond saw from four freshly extracted intact first molars. The coronal dentin surface of each disk was divided into four regions, each approximately 2 mm × 3 mm. The dentin surfaces were treated with 27% EDTA then the four regions irradiated separately in a randomized pattern with a Nd:YAG laser (120 mJ, 5 Hz), using irradiation times of 0 s, 20 s, 40 s and 60 s, representing laser energies of 0 J/cm², 200 J/cm², 400 J/cm² and 600 J/cm², respectively. SEM photomicro-graphs were taken at 1500× and 3000× to calculate the dentinal tubule orifice occlusion rates and to measure the tubule diameters, respectively. Results: For the laser irradiation times of 0 s, 20 s, 40 s and 60 s, the corresponding dentinal tubule occlusion rates were 2.05 (SD 0.29)%, 10.01 (1.71)%, 23.58 (2.51)% and 90.23 (2.24)%, respectively; and the tubule diameters were 4.18 (0.32) μm, 3.46 (0.24) μm, 1.69 (0.32) μm and 0.12 (0.02) μm, respectively. There were significant differences among all groups for both measured variables (p ≤ 0.005). Conclusions: Within the limitations of this in Vitro study, when using a Nd:YAG laser at 120 mJ and 5 Hz, an irradiation time of 60 s achieved the best sealing of the coronal dentinal tubule orifices.

Keywords

Nd:YAG Laser, Dentinal Tubule, Scanning Electron Microscope

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Holland, G.R., Narhi, M.N., Addy, M., Gangarosa, L. and Orchardson, R. (1997) Guidelines for the Design and Conduct of Clinical Trials on Dentine Hypersensitivity. Journal of Clinical Periodontology, 24, 808-813. http://dx.doi.org/10.1111/j.1600-051X.1997.tb01194.x
[2]	Orchardson, R. and Gillam, D.G. (2006) Managing Dentin Hypersensitivity. The Journal of the American Dental Association, 137, 990-998. http://dx.doi.org/10.14219/jada.archive.2006.0321
[3]	Dilsiz, A., Canakci, V., Ozdemir, A. and Kaya, Y. (2009) Clinical Evaluation of Nd:YAG and 685-nm Diode Laser Therapy for Desensitization of Teeth with Gingival Recession. Photomedicine and Laser Surgery, 27, 843-848. http://dx.doi.org/10.1089/pho.2008.2395
[4]	Canakci, C.F. and Canakci, V. (2007) Pain Experienced by Patients Undergoing Different Periodontal Therapies. The Journal of the American Dental Association, 138, 1563-1573. http://dx.doi.org/10.14219/jada.archive.2007.0105
[5]	Gholami, G.A., Fekrazad, R., Esmaiel-Nejad, A. and Kalhori, K.A. (2011) An Evaluation of the Occluding Effects of Er;Cr:YSGG, Nd:YAG, CO2 and Diode Lasers on Dentinal Tubules: A Scanning Electron Microscope in Vitro Study. Photomedicine and Laser Surgery, 29, 115-121. http://dx.doi.org/10.1089/pho.2009.2628
[6]	Al-Saud, L.M. and Al-Nahedh, H.N. (2012) Occluding Effect of Nd:YAG Laser and Different Dentin Desensitizing Agents on Human Dentinal Tubules in Vitro: A Scanning Electron Microscopy Investigation. Operative Dentistry, 37, 340-355. http://dx.doi.org/10.2341/10-188-L
[7]	Palazon, M.T., Scaramucci, T., Aranha, A.C., Prates, R.A., Lachowski, K.M., Hanashiro, F.S., et al. (2013) Immediate and Short-Term Effects of In-Office Desensitizing Treatments for Dentinal Tubule Occlusion. Photomedicine and Laser Surgery, 31, 274-282. http://dx.doi.org/10.1089/pho.2012.3405
[8]	Brannstrom, M. and Astrom, A. (1972) The Hydrodynamics of the Dentine; Its Possible Relationship to Dental Pain. International Dental Journal, 22, 219-227.
[9]	Farmakis, E.-R.T., Kozyrakis, K, Khabbaz, M.G., Schoop, U., Beer, F. and Moritz, A. (2012) In Vitro Evaluation of Dentin Tubule Occlusion by Denshield and Neodymium-Doped Yttrium-Aluminum-Garnet Laser Irradiation. Journal of Endodontics, 38, 662-666. http://dx.doi.org/10.1016/j.joen.2012.01.019
[10]	Farmakis, E.-R.T., Beer, F., Kozyrakis, K., Pantazis, N. and Moritz, A. (2013) The Influence of Different Power Settings of Nd:YAG Laser Irradiation, Bioglass and Combination to the Occlusion of Dentinal Tubules. Photomedicine and Laser Surgery, 31, 54-58. http://dx.doi.org/10.1089/pho.2012.3333
[11]	Lan, W.-H., Lee, B.-S., Liu, H.-C. and Lin, C.-P. (2004) Morphological Study of Nd:YAG Laser Usage in Treatment of Dentinal Hypersensitivity. Journal of Endodontics, 30, 131-134. http://dx.doi.org/10.1097/00004770-200403000-00001
[12]	Malkoc, M.A. and Sevimay, M. (2012) Evaluation of Mineral Content of Dentin Treated with Desensitizing Agents and Neodymium Yttrium-Aluminium-Garnet (Nd:YAG) Laser. Lasers in Medical Science, 27, 743-748. http://dx.doi.org/10.1007/s10103-011-0954-6
[13]	Birang, R., Poursamimi, J., Gutknecht, N., Lampert, F. and Mir, M. (2007) Comparative Evaluation of the Effects of Nd:YAG and Er:YAG Laser in Dentin Hypersensitivity Treatment. Lasers in Medical Science, 22, 21-24. http://dx.doi.org/10.1007/s10103-006-0412-z
[14]	He, S., Wang, Y., Li, X. and Hu, D. (2011) Effectiveness of Laser Therapy and Topical Desensitising Agents in Treating Dentine Hypersensitivity: A Systematic Review. Journal of Oral Rehabilitation, 38, 348-358. http://dx.doi.org/10.1111/j.1365-2842.2010.02193.x
[15]	Liu, H.-C., Lin, C.-P. and Lan, W.-H. (1997) Sealing Depth of Nd:YAG Laser on Human Dentinal Tubules. Journal of Endodontics, 23, 691-693. http://dx.doi.org/10.1016/S0099-2399(97)80403-7
[16]	Song, Y.X., Liu, L.C., He, H.X., Xiong, H. and An, J.P. (2002) Dentinal Morphological Changes after Nd:YAG Laser Irradiation. West China J. Stomatology. 20, 429-431. (In Chinese)
[17]	Zapletalová, Z., Perina Jr., J., Novotny, R. and Chmelícková, H. (2007) Suitable Conditions for Sealing of Open Dentinal Tubules Using a Pulsed Nd:YAG laser. Photomedicine and Laser Surgery, 25, 495-499. http://dx.doi.org/10.1089/pho.2007.2085
[18]	Abed, A.M., Mahdian, M., Seifi, M., Ziaei, S.A. and Shamsael, M. (2011) Comparative Assessment of the Sealing Ability of Nd:YAG Laser versus a New Desensitizing Agent in Human Dentinal Tubules: A Pilot Study. Odontology, 99, 45-48. http://dx.doi.org/10.1007/s10266-010-0136-1
[19]	Lan, W.-H., Liu, H.-C. and Lin, C.-P. (1999) The Combined Occluding Effect of Sodium Fluoride Varnish and Nd:YAG Laser Irradiation on Human Dentinal Tubules. Journal of Endodontics, 25, 424-426. http://dx.doi.org/10.1016/S0099-2399(99)80271-4