Milena Góes Guarda

Influence of the λ780nm laser light on the repair of surgical bone defects grafted or not with biphasic synthetic micro-granular hydroxylapatite+Beta-Calcium triphosphate.

The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve repair, including a wide range of biomaterials and, recently, photobioengineering. This work aimed to assess, through histological analysis The aim of this study was to assess, by light microscopy, the repair of bone defects grafted or not with biphasic synthetic micro-granular Calcium hydroxyapatite (HA)+Beta-TCP associated or not with Laser phototherapy - LPT (λ780nm). Forty rats were divided into 4 groups each subdivided into 2 subgroups according to the time of sacrifice (15 and 30days). Surgical bone defects were made on femur of each animal with a trephine drill. On animals of Clot group the defect was filled only by blood clot, on Laser group the defect filled with the clot was further irradiated. On animals of Biomaterial and Laser+Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ780nm, 70mW, spot size∼0.4cm(2), 20J/cm(2)-session, 140J/cm(2)-treatment) in four points around the defect at 48-h intervals and repeated for 2weeks. At both 15th and 30th days following sacrifice, samples were taken and analyzed by light microscopy. Many similarities were observed histologically between groups on regards bone reabsorption and neoformation, inflammatory infiltrate and collagen deposition. The criterion degree of maturation, marked by the presence of basophilic lines, indicated that the use of LPT associated with HA+Beta TCP graft, resulted in more advanced stage of bone repair at the end of the experiment.

Laser GaAlAs (λ860 nm) photobiomodulation for the treatment of bisphosphonate-induced osteonecrosis of the jaw.

OBJECTIVE The aim of this article is to report a case of bisphosphonate-induced osteonecrosis (ONJ-BP) of the jaw treated by curettage of the necrotic bone, low-level laser therapy (LLLT), and antibiotic therapy. BACKGROUND DATA ONJ-BP is characterized by painful ulcerations of the oral mucosa, is prone to bone necrosis that does not heal within 8 weeks after diagnosis, and is often difficult to treat. No definitive standard of care has been established for ONJ-BP. LLLT improves wound healing, relieves pain, and appears to be a promising treatment modality for patients with ONJ-BP. MATERIALS AND METHODS An 82-year-old man taking intravenous bisphosphonate presented with ONJ-BP after tooth extraction. The patient was treated by LLLT using a GaAlAs diode laser with the following settings: wavelength, 860 nm; 70 mW; continuous wave; and spot size 4 mm(2). An energy density of 4.2 J/cm(2) per point was applied in a punctual contact manner every 48 h for 10 days, in association with antibiotic therapy and curettage of the necrotic bone. Reduction in painful symptoms was reported after the second irradiation session, and tissue healing was complete at the end of the third week following oral curettage. The patient was followed up for 12 months and exhibited good oral healt and quality of life. CONCLUSIONS The therapeutic protocol used in this study had a positive effect on tissue healing and remission of painful symptoms, resulting in better oral health and quality of life for the patient.

Repair of surgical bone defects grafted with hydroxylapatite + β-TCP and irradiated with λ=850 nm LED light.

The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve the repair, including a wide range of biomaterials and recently, photobioengineering. This work aimed to assess by histological analysis the repair of bone defects grafted with biphasic synthetic micro-granular HA + β-TCP associated with LED phototherapy. Forty rats were divided into 4 groups (Clot, LED, Biomaterial and LED + Biomaterial) each subdivided into 2 subgroups according to the time of animal death (15 and 30 days). Surgical bone defects were prepared on the femur of each animal with a trephine drill. In animals of the Clot group the defect was filled only by blood clot, in the LED group the defect filled with the clot was further irradiated. In the animals of Biomaterial and LED + Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ = 850 ± 10 nm, 150 mW, Φ ~ 0.5 cm2, 20 J/cm2 - session, 140 J/cm2- treatment) at 48-h intervals for 2 weeks. Following animal death, samples were taken and analyzed by light microscopy. Using the degree of maturation of the bone by assessment of the deposition/organization of the basophilic lines in the newly formed bone tissue, the LED + Biomaterial group was the one in a more advanced stage of bone repair process at the end of the experiment. It may be concluded that the use of LED phototherapy was effective in positively modulating the process of bone repair of bone defects in the femur of rats submitted or not to biomaterial grafting.

Effect of LED phototherapy (λ630 ± 20nm) on mast cells during wound healing in hypothyroid

Hypothyroidism has been associated with the disruption of the bodys metabolism, including the healing process. LED phototherapy has been studied using several healing models, but their effects on mast cells proliferation associated to hypothyroidism remains unknown. The aim of this study was to assess the effect LED (λ630±20nm) phototherapy on mast cells proliferation during tissue repair in hypothyroid rats. Under general anesthesia, a standard surgical wound (1cm2) was created on the dorsum of 24 male Wistar rats divided into 4 groups of 6 animals each: EC-Control Euthyroid; ED-Euthyroid+LED; HC-Control Hypothyroid and HD-Hypothyroid+LED. The irradiation started immediately after surgery and was repeated every other day for 7 days, when animals death occurred. Hypothyroidism was induced in rats with propylthiouracil (0.05g/100mL) administered orally for 4 weeks and maintained until the end of the experiment. The specimens removed were processed to wax and stained with toluidine blue for mast cell identification. The mast cell proliferation was significantly higher in HC group than in EC group (Mann Whitney, p<0.05), but when ED group was compared to HD group, no significant difference was found. Our results showed that there was increase of mast cells in the presence of hypothyroidism, prolonging the inflammatory phase of repair, and the LED light has a biomodulative effect on mast cell population, even when hipothyroidism was present.