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Laser Irradiation of Bone: II. Healing Response Following Treatment by CO 2 and Nd:YAG Lasers
Author(s) -
Friesen Lynn R.,
Cobb Charles M.,
Rapley John W.,
ForgasBrockman Lorraine,
Spencer Paulette
Publication year - 1999
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.1999.70.1.75
Subject(s) - laser , irradiation , bone healing , medicine , materials science , dentistry , optics , surgery , physics , nuclear physics
Background: Currently, the most commonly used lasers for dental procedures are the Nd:YAG and CO 2 . Studies comparing healing of osteotomy defects prepared with rotary burs to those created by laser irradiation have reported conflicting results. The purpose of this study was to evaluate and compare the histologic healing of bone in rat tibial osteotomy defects created either by a dental bur, CO 2 laser with and without removal of the char layer, and Nd:YAG laser with char layer removed and with and without use of an air/water surface cooling spray. Methods: Tibial osteotomy defects were created in 4 groups of 6 rats each using the following: 1) #6 round bur with simultaneous saline irrigation; 2) CO 2 laser with char layer intact; 3) CO 2 laser with char layer removed; 4) Nd:YAG laser with air/water surface cooling, and char layer intact; 5) Nd:YAG laser with air/water surface cooling, and char layer removed; and 6) Nd:YAG laser without air/water surface cooling, and char layer removed. Both laser types were used at energy densities typically utilized for oral soft tissue surgery. Results: Progressive healing from day 0 through day 21 post‐treatment was observed in all treatment groups. However, compared to controls treated by rotary dental bur, those specimens treated by laser, regardless of laser type, energy density, or other parameters, exhibited a delay in healing that appeared to be related to the presence of residual char in the osseous defect. Specimens treated with the Nd:YAG laser using an air/water surface coolant exhibited a decreased thickness and continuity of the char layer and yielded the only specimens with new bone formation at the surface of the laser ablation defect. In addition, the normal pattern of bone remodeling in the rat tibia appeared to have been altered by laser irradiation. Conclusions: In this animal model, laser‐induced osteotomy defects, when compared to those prepared by rotary bur, exhibited a delayed healing response that appeared to be related to the presence of residual char in the osseous defect. J Periodontol 1999; 70: 75‐83.