Effects of Laser Therapy in CO2Laser Wounds in Rats

Evaluation of the effect of photodynamic therapy on chemotherapy induced oral mucositis

BACKGROUND

In this study the effect of photodynamic therapy on chemotherapy induced mucositis was evaluated.

METHODS

This randomized single blind clinical pilot evaluation evaluated the effect of PDT with methylene blue on 15 patients with chemotherapy induced bilateral oral mucositis. They were divided into 2 groups (control side and intervention side). Methylene blue was applied on the lesions of both sides, after 10 min the lesion of intervention side was irradiated by a 660 nm diode laser InGaAlP(Azor-2 K) for 10 min (power: 25 mW, dose:19.23 J/CM2, probe diameter: 0.78 cm2) for three sessions (day1,3,5) and followed on day 12. In control side only sham laser was used. Data were analyzed by Wilcoxon and Mann-Whitney test using SPSS version 22.

RESULTS

Comparing the WCCNR and NCI difference in different sessions between intervention and control group, represented significant improvement in oral mucositis in photodynamic therapy group for sessions 1-0, 2-0, 3-0 (P.value<0.05).

CONCLUSION

Photodynamic therapy can improve chemotherapy induced oral mucositis.

Development of a reproducible in vivo laser-induced scar model for wound healing study and management

The aim of the current study was to establish animal scar models in a simple and rapid manner by comparing three methods. Wounds were created on the buttocks of Sprague Dawley rats. For Group 1, the initial wound was created by surgical incision. For Groups 2 and 3, a 1470-nm laser was employed to generate dermal burns as the initial wound. The wounds in Groups 1 and 3 were then sutured for three days. After the wound healing, Group 2 generated the largest collagen proportion with abundant collagen type I and significant increases in α-SMA and TGF-β1. The proposed method can be an efficient way to develop rat scar models in a simple manner for evaluating scar treatment.

Low-level laser irradiation affects the release of basic fibroblast growth factor (bFGF), insulin-like growth factor-I (IGF-I), and receptor of IGF-I (IGFBP3) from osteoblasts

OBJECTIVE

It was the aim of the present study to evaluate whether the laser irradiation of osteoblasts could enhance the release of growth factors including basic fibroblast growth factor (bFGF), insulin-like growth factor-I (IGF-I), and receptor of IGF-I (IGFBP3).

BACKGROUND DATA

Low-level laser therapy (LLLT) has been shown to have biostimulatory effects on various cell types by enhancing production of some cytokines and growth factors.

MATERIALS AND METHODS

Human mesenchymal stem cells (MSCs) were seeded in osteogenic medium and differentiated into osteoblasts. Three groups were formed: in the first group (single dose group), osteoblasts were irradiated with laser (685 nm, 25 mW, 14.3 mW/cm(2), 140 sec, 2 J/cm(2)) for one time; and in the second group, energy at the same dose was applied for 2 consecutive days (double dose group). The third group was not irradiated with laser and served as the control group. Proliferation, viability, bFGF, IGF-I, and IGFBP3 levels were compared between groups.

RESULTS

Both of the irradiated groups revealed higher proliferation, viability, bFGF, IGF-I, and IGFBP3 expressions than did the nonirradiated control group. There was increase in bFGF and IGF-I expressions and decrease in IGFBP3 in the double dose group compared to single dose group.

CONCLUSIONS

The results of the present study indicate that LLLT increases the proliferation of osteoblast cells and stimulates the release of bFGF, IGF-I, and IGFBP3 from these cells. The biostimulatory effect of LLLT may be related to the enhanced production of the growth factors.

Removal of oral lichen planus by CO2 laser

The aim of this case report is to present a histologically diagnosed oral lichen planus excised by the CO2 laser. Oral lichen planus is a chronic inflammatory mucocutaneous disease of unknown etiology. Different treatments have been used to manage this condition. A 46 year-old female was referred to the Laser Clinic of the Dental School of the Federal University of Bahia to excise a lesion characterized by white patches on the oral mucosa, which was causing pain and burning sensation and had not respond to treatment with triamcinolone and corticosteroids for 3 months. CO2 laser was used to remove the lesion and the conclusive histopathological diagnosis was oral lichen planus. The patient was followed up over 1year with no signs of lesion recurrence. The use of the CO2 laser was found to be useful and effective to treat lichen planus.

Healing of surgical wounds made with lambda970-nm diode laser associated or not with laser phototherapy (lambda655 nm) or polarized light (lambda400-2000 nm)

OBJECTIVE

The aim of this study was to analyze the effect of two phototherapies, laser and polarized light, on diode laser (970lambda nm) wounds.

BACKGROUND DATA

Lasers have been used in surgery, and some wavelengths may cause thermal damage to the tissue and affect healing. Several studies have shown that some wavelengths are effective in improving healing. Coherent and noncoherent light have been successfully used on the modulation of biological phenomena of several origins.

ANIMALS AND METHODS

Thirty-one Wistar rats were divided into 3 groups (GI to GIII). A 20-mm x 2-mm wound was created on the dorsum of each animal with a diode laser (Sirolaser, Sirona, Bensheim, Germany). Group GI acted as control. On GII, laser light (lambda655 nm, 30 mW, phi approximately 3 mm, 12 J/cm(2)) was used and on GIII illumination with polarized light (lambda400-2000 nm, 40 mW, phi approximately 5.5 cm, 12 J/cm(2)) was used, every other day (GII) or daily (GIII) for 7 days. The animals were killed at 0, 7, and 14 days after surgery. Specimens were taken, routinely processed, stained and imunnomarked [HE (hematoxylin-eosin), sirius red, alpha-smooth muscle actin (SMA)], and underwent histological analysis.

RESULTS

GII showed better response at day 14 when re-epithelialization was in a more advanced stage. The number of myofibroblasts was significantly different over the healing time (7 to 14 days); this number was smaller than that observed on G1. On GIII at day 7, the number of myofibroblasts was significantly higher than for GII. At day 14, a more pronounced deposition of collagen matrix was also seen, and inflammation was discrete and more advanced for GIII.

CONCLUSION

The results of the present study showed that the effect of the use of laser light was more evident at early stages of healing and that the use of polarized light improved the resolution of the inflammatory reaction, increased the deposition of collagen, increased the number of myofibroblasts, and quickened re-epithelialization during the experimental time.

Comparison of carbon dioxide laser and scalpel for breast lumpectomy: a randomized controlled trial

OBJECTIVE

To investigate whether the CO2 laser is superior to conventional surgical techniques for minor breast surgery in a randomized clinical trial.

BACKGROUND DATA

It has been suggested in the literature that application of CO2 laser in breast surgery might be superior to conventional surgery in some aspects.

PATIENTS AND METHODS

Sixty women whose breast masses were suitable for excisional biopsy were randomly allocated to laser and control (conventional surgical technique with scalpel) groups. Perioperative and postoperative variables were recorded and analyzed.

RESULTS

The patients' ages ranged from 16-63 y. There were no significant differences between the two groups in total operative time (17.4 min with laser and 17.5 min with scalpel). There was a significant decrease in the required dose of lidocaine in the laser group (9.3 mL) compared to the scalpel group (12.4 mL; p = 0.01). In addition, hemorrhage was significantly lower in the laser group (6.6 mL) compared to the control group (11.9 mL; p = 0.006). There was no difference in the grade of the scar or postoperative pain between the two groups.

CONCLUSION

Use of the CO2 laser in breast mass biopsy has some advantages, including a lower requirement for local anesthetic and a lower rate of intraoperative bleeding. Furthermore, using the laser does not prolong the operative time.

Microstructural changes of enamel, dentin-enamel junction, and dentin induced by irradiating outer enamel surfaces with CO2 laser

The microstructural changes of enamel, dentin-enamel junction (DEJ), and dentin after CO(2) laser irradiation were studied. Buccal enamel surfaces of human third molars about 2 mm from the DEJ were irradiated, and the laser tip was moved 5 mm in a mesiodistal direction with 5 s of irradiation time. The output powers were 2 to 10 W in a continuous mode, and the average doses were approximately from 250 to 1,250 J/cm(2). All specimens were examined by a scanning electron microscope, and heat-transfer simulation was also applied to calculate temperature distribution. Surface ablation of enamel and separation of enamel and dentin along the DEJ were observed when the laser power output exceeded 3 W. Heat-transfer simulation indicated that dentin was prone to store more thermal energy than enamel. In conclusion, operation parameters of the CO(2) laser should be carefully selected to avoid thermal damage to the DEJ.