Effects of laser radiation on the subjective symptoms of eyes / 中国职业医学

OBJECTIVE: To investigate the subjective symptoms of eyes induced by laser radiation in workers and its related influencing factors. METHODS: A total of 82 workers exposed to laser radiation were taken as exposure group, and 71 workers without laser radiation exposure as control group by judgment sampling method. The questionnaire survey and subjective symptoms of eyes were surveyed in these two groups. The work-site surveys of laser radiation job posts and laser irradiation testing were conducted to evaluate the exposure level of laser radiation on each post. The basic eye use and eye discomfort symptoms were investigated. RESULTS: The median of the laser radiation in 12 workplaces was 2.18×10~(-5) W/cm~2, and it was below occupational exposure limit(2.22×10~(-3) W/cm~2). The total detection rate of subjective discomfort of eyes in the exposed group was significantly higher than that in the control group(35.4% vs 15.5%, P<0.05). The results of multivariate logistic regression analysis indicated that laser exposure and smoking were the risk factors of subjective symptoms of eyes(P<0.05). CONCLUSION: Laser radiation operation has the risk of causing the subjective symptoms of eyes in exposed workers.

Láser de baja potencia en Ortodoncia / Low-level laser in orthodontics

Introducción: durante los últimos años la Ortodoncia demanda tratamientos más cortos. La duración del tratamiento depende del diagnóstico, complejidad del caso, plan de tratamiento, aparatología, experiencia clínica y cooperación del paciente, entre otros, y generalmente oscila entre 24 y 36 meses. Existen estudios que avalan el láser de baja potencia acelera el movimiento ortodóntico, sin embargo, los mecanismos de la fotobiomodulación asociados a esto están claros. Objetivo: describir la evidencia asociada a la fotobiomodulación por láser de baja potencia en el movimiento ortodóntico y sus mecanismos. Métodos: se realizó una revisión bibliográfica sobre la relación existente entre la fotobiomodulación por láser de baja potencia en el movimiento ortodóntico y sus mecanismos en MEDLINE, PubMed y SciELO. La búsqueda se orientó a artículos publicados fundamentalmente en los últimos 5 años sin hacer distinciones de idioma. Los tópicos consultados en la revisión estuvieron referidos a estudios experimentales en humanos, animales e in vitro que incluyeran los láseres que emiten luz infrarroja (780-820 nm), debido a que la absorción infrarroja de la hemoglobina es menor que la del rojo visible. Los láseres que emiten luz infrarroja (780-820 nm) son los mejores para estimular las células óseas porque sus longitudes de onda penetran más profundamente en el tejido blando, alcanzando el tejido óseo. Resultados: se profundiza en el tema de la fotobiomodulación y las bases modulares del empleo de esta técnica en Ortodoncia. El láser de baja potencia acelera el movimiento ortodóntico, sin embargo, no se ha determinado una ventana terapéutica específica para la dosimetría y el mecanismo de acción a nivel de tipos de células individuales. Conclusiones: la evidencia sugiere que el láser de baja potencia acelera el movimiento ortodóntico. Sobre los mecanismos celulares implicados en el movimiento ortodóntico cuando son irradiados con láser, aún la evidencia clínica es insuficiente(AU)

Introduction: recent years have witnessed a demand for ever shorter treatments in orthodontics. Treatment duration depends on diagnosis, case complexity, treatment plan, equipment, clinical experience and patient cooperation, among other factors, and generally ranges between 24 and 36 months. Some studies support the idea that low-level laser speeds up orthodontic movement; however, the photobiomodulation mechanisms involved are clear. Objective: describe the evidence of low-level laser photobiomodulation in orthodontic movement and its mechanisms. Methods: a bibliographic review was conducted in MEDLINE, PubMed and SciELO about the relationship between low-level laser photobiomodulation in orthodontic movement and its mechanisms. The search was aimed at papers published in any language mainly in the last five years. The topics consulted in the review had to do with experiments on humans, animals and in vitro in which infrared lasers (780-820 nm) were used, since infrared absorption of hemoglobin is lower than that of visible red. Infrared lasers (780-820 nm) are the best to stimulate bone cells, because their wavelengths go deeper into soft tissue, reaching the bone. Results: details are provided about photobiomodulation and the modular bases of the use of this technique in orthodontics. Low-level laser speeds up orthodontic movement; however, a specific therapeutic window has not been determined for its dosimetry and mechanism of action in individual cell types. Conclusions: evidence suggests that low-level laser speeds up orthodontic movement. Clinical evidence is still insufficient about the cellular mechanisms involved in orthodontic movement when laser radiation is used(AU)

Optical Radiation Safety Evaluation and Control of Laser Medical Equipment / 中国医疗器械杂志

Optical radiation hazards and the evaluation method of optical radiation safety of laser medical equipment are introduced in this paper. According to the requirement of YY/T 0316-2008, the corresponding solutions of safety control are put forward in this paper to minimize the risk of optical radiation, making sure the safety and effectiveness of laser medical equipment.

Observations on the Cumulative Biological Effect of Acupoint Laser Radiation and Its Analgesic Effect in Adjuvant Arthritis Rats / 上海针灸杂志

Objective To explore the mechanism of the cumulative biological effect of acupoint laser radiation and investigate its analgesic effect by comparing the therapeutic effects of semiconductor laser radiation versus acupuncture at point Zusanli(ST36) in acute adjuvant arthritis rats and to provide the experiment-based theoretical foundation and basis for the course of treatment of acute arthritis pain by clinical use of semiconductor laser. Method A rat model of AA was made by subcutaneous injection of complete Freund's adjuvant into rat toe. Eighty rats were randomly allocated to eight groups:model, blank, three-day laser radiation, five-day laser radiation, seven-day laser radiation, three-day acupuncture, five-day acupuncture and seven-day acupuncture treatment groups, 10 rats each. The three laser groups separately received 650 nm semiconductor laser radiation. The three acupuncture groups separately received acupuncture with a filiform needle at point Zusanli(ST36) on the inflammation-affected side. Rat general condition, body weight, pain threshold value and ankle swelling degree were observed. Serum inflammatory factors IL-1、TNF-αand IFN-γcontents were measured by ELISA. Result There were statistically significant posttreatment differences in body weight, joint swelling degree and pain threshold between the laser treatment and acupuncture treatment groups of rats (P<0.05). There was a statistically significant post-treatment difference in joint swelling degree between three-day laser, five-day laser and seven-day laser treatment groups (P<0.05). Pain threshold was lowest at five days after treatment and increased somewhat at seven days after treatment in both the three-day laser and three-day acupuncture treatment groups. The IL-1 content tended to decrease on the whole and had a decreasing tendency at three and five days after treatment in both laser and acupuncture treatment groups. At seven days after treatment, it reached the lowest value in the laser treatment group but had a marked increasing tendency in the acupuncture treatment group. The IFN-γcontent had an increasing tendency at three and five days after treatment in both laser and acupuncture treatment groups. The IFN-γcontent tended to change gently in the laser treatment group from day five to seven after treatment. It tended to decrease from day five to seven after acupuncture treatment but was still higher than in the three-day acupuncture treatment group. The TNF-αcontent tended to decrease from day three to five after treatment in both laser and acupuncture treatment groups. From day five to seven after treatment, it tended to decrease gently in the laser treatment group but tended to increase slightly in the acupuncture treatment group. Conclusion Both semiconductor laser radiation and acupuncture at point Zusanli have an anti-inflammatory and analgesic effect and can relieve the general symptoms in AA rats, but semiconductor laser radiation is significantly superior to acupuncture treatment in eliminating inflammation and easing pain and produces a more timely and better therapeutic effect. After semiconductor laser radiation at acupoints, the related serum cytokines tended to increase or decrease slowly in AA rats after the turning point appeared during the treatment, which embodies the parabola feature of laser radiation treatment. It is showed that with an increase in laser radiation length, the biological effect of laser accumulates, suggesting that attention should be paid to the cumulative effect during laser treatment.

Effect of Intravenous Low Intensity Laser Radiation Combined with TCM on Model Rabbit of Diabetic Stroke / 中国中医药信息杂志

Objective To observe the effect of intravenous low intensity laser radiation (ILLLI) combined with traditional Chinese medicine on TXB2, 6-Keto-PGF1? and Ang II of the rabbits of experimental diabetic stroke. Method 35 successfully modeled rabbits, after alloxian injection for diabetes and photochemical radiation for stroke, were randomized into four treatment group-control group (B), ILIB group (C), a group with compound treatment of ILIB and TCH (D), TCM treatment group (E), and 7 unmodeled rabbits were made as the normal group (A). TXB2, 6-Keto-PGF1? and Ang II level were observed and compared. Result Compared with group B, group C and E can significantly rectify the disorderly TXB2, 6-Keto-PGF1? and Ang II, Group D was better than C and E. Conclusion ILLLI combined with TCM can effectively rectify the TXB2, 6-Keto-PGF1? and Ang II level, reduce nervous injury, cure diabetes cerebral infarction.