Nissan J, Assif D, Gross M D, Yaffe A, Binderman I
Department of Oral Rehabilitation, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
J Oral Rehabil. 2006 Aug;33(8):619-924. doi: 10.1111/j.1365-2842.2006.01601.x.
Low intensity lasers have been used by clinicians to improve healing and reduce pain in humans. Lasing also results in new bone formation around hydroxyapatite implants and a significant increase in the total bone area. However, the exact mechanism of cell biostimulation by laser is still unclear. This study biochemically assessed the effects of low intensity laser (Gallium-Arsenide) using 4 and 22.4 mW cm(-2) power density on the bone healing process after surgically creating bony cavities in rat mandibles. Rats (n = 24) were divided into two groups each treated with specific energy, 4 or 22.4 mW cm(-2), for 3 min each day post-surgery. Surgical cavities were created on both sides of the mandible: the left served as an untreated control, the right was treated with laser. All rats were sacrificed after 1, 2 and 4 weeks of treatment. In the newly formed callus, accumulation of radiocalcium and alkaline phosphatase activity was measured to indicate osteogenic activity. One-way anova with repeated measures showed that the low intensity laser using 4 mW cm(-2) power density significantly increased radiocalcium accumulation from 2 weeks post-surgery, whereas 22.4 mW cm(-2) had no effect. No changes were noted in the activity of alkaline phosphatase with the laser treatment. These results suggest that laser therapy of low power density is effective on the bone healing process in artificially created osseous cavities by affecting calcium transport during new bone formation.
临床医生已使用低强度激光来促进人类伤口愈合并减轻疼痛。激光照射还会导致羟基磷灰石植入物周围形成新骨，且骨总面积显著增加。然而，激光对细胞进行生物刺激的确切机制仍不清楚。本研究通过生物化学方法评估了使用功率密度为4和22.4 mW/cm²的低强度激光（砷化镓）对大鼠下颌骨手术制造骨腔后骨愈合过程的影响。将大鼠（n = 24）分为两组，每组在术后每天接受特定能量（4或22.4 mW/cm²）照射3分钟。在下颌骨两侧制造手术腔：左侧作为未处理的对照，右侧用激光处理。在治疗1、2和4周后处死所有大鼠。在新形成的骨痂中，测量放射性钙的积累和碱性磷酸酶活性以指示成骨活性。重复测量的单向方差分析表明，使用4 mW/cm²功率密度的低强度激光从术后2周起显著增加了放射性钙的积累，而22.4 mW/cm²则没有效果。激光治疗后碱性磷酸酶活性未发现变化。这些结果表明，低功率密度的激光疗法通过影响新骨形成过程中的钙转运，对人工制造的骨腔中的骨愈合过程有效。
