Antonio Luiz Barbosa Pinheiro

New Bone Formation around Implants Inserted on Autologous and Xenografts Irradiated or not with IR Laser Light: A Histomorphometric Study in Rabbits

Use of biomaterials and light on bone grafts has been widely reported. This work assessed the influence of low-level laser therapy (LLLT) on bone volume (BV) and bone implant contact (BIC) interface around implants inserted in blocks of bovine or autologous bone grafts (autografts), irradiated or not, in rabbit femurs. Twenty-four adult rabbits were divided in 8 groups: AG: autograft; XG: xenograft; AG/L: autograft + laser; XG/L: xenograft + laser; AG/I: autograft + titanium (Ti) implant; XG/I: xenograft + Ti implant; AG/I/L: autograft + Ti implant + laser; and XG/I/L: xenograft + Ti implant + laser. The animals received the Ti implant after incorporation of the grafts. The laser parameters in the groups AG/L and XG/L were λ=780 nm, 70 mW, CW, 21.5 J/cm 2 , while in the groups AG/I/L and XG/I/L the following parameters were used: λ=780 nm, 70 mW, 0.5 cm 2 (spot), 4 J/cm 2 per point (4), 16 J/cm 2 per session, 48 h interval × 12 sessions, CW, contact mode. LLLT was repeated every other day during 2 weeks. To avoid systemic effect, only one limb of each rabbit was double grafted. All animals were sacrificed 9 weeks after implantation. Specimens were routinely stained and histomorphometry carried out. Comparison of non-irradiated and irradiated grafts (AG/L versus AG and XG/L versus XG) showed that irradiation increased significantly BV on both grafts (p=0.05, p=0.001). Comparison between irradiated and non-irradiated grafts (AG/I/L versus AG/I and XG/I/L versus XG/I) showed a significant (p=0.02) increase of the BIC in autografts. The same was seen when xenografts were used, without significant difference. The results of this investigation suggest that the use of LLLT is effective for enhancing new bone formation with consequent increase of bone-implant interface in both autologous grafts and xenografts.

Photodynamic antimicrobial chemotherapy (PACT) using phenothiazine derivatives as photosensitizers against Leishmania braziliensis.

Cutaneous and mucocutaneous leishmaniasis are diseases characterized by skin or mucosal manifestations. In the new world, Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis, condition that may evolve to the mucocutaneous form. The therapeutic arsenal routinely employed to treat infected patients is unsatisfactory, especially for pentavalent antimonials, treatment recommended by the WHO, as they are often highly toxic, poorly tolerated and of variable effectiveness. This work aimed to evaluate in vitro the effectiveness of photodynamic antimicrobial chemotherapy as a new approach for the treatment of leishmaniasis.

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.

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 1 year with no signs of lesion recurrence. The use of the CO2 laser was found to be useful and effective to treat lichen planus.

Raman ratios on the repair of grafted surgical bone defects irradiated or not with laser (λ780 nm) or LED (λ850 nm)

This work aimed to assess biochemical changes associated to mineralization and remodeling of bone defects filled with Hydroxyapatite+Beta-Beta-tricalcium phosphate irradiated or not with 2 light sources. Ratios of intensities, band position and bandwidth of selected Raman peaks of collagen and apatites were used. Sixty male Wistar rats were divided into 6 groups subdivided into 2 subgroups (15th and 30th days). A standard surgical defect was created on one femur of each animal. In 3 groups the defects were filled with blood clot (Clot, Clot+Laser and Clot+LED groups) and in the remaining 3 groups the defects were filled with biomaterial (Biomaterial, Biomaterial+Laser and Biomaterial+LED groups). When indicated, the defects were irradiated with either Laser (λ780 nm, 70 mW, Φ∼0.4 cm(2)) or LED (λ850±10 nm, 150 mW, Φ∼0.5 cm(2)), 20 J/cm(2) each session, at 48 h intervals/2 weeks (140 J/cm(2) treatment). Following sacrifice, bone fragments were analyzed by Raman spectroscopy. Statistical analysis (ANOVA General Linear Model, p<0.05) showed that both grafting and time were the variables that presented significance for the ratios of ∼1660/∼1670 cm(-1) (collagen maturation), ∼1077/∼854 cm(-1) (mineralization), ∼1077/∼1070 cm(-1) (carbonate substitution) and the position of the ∼960 cm(-1) (bone maturation). At 30th day, the ratios indicated an increased deposition of immature collagen for both Clot and Biomaterial groups. Biomaterial group showed increased collagen maturation. Only collagen deposition was significantly dependent upon irradiation independently of the light source, being the amount of collagen I increased in the Clot group at the end of the experimental time. On the other hand, collagen I deposition was reduced in biomaterial irradiated groups. Raman ratios of selected protein matrix and phosphate and carbonate HA indicated that the use of biphasic synthetic micro-granular HA+Beta-TCP graft improved the repair of bone defects, associated or not with Laser or LED light, because of the increasing deposition of HA.

Surgical treatment of oral lymphangiomas with CO2 laser: report of two uncommon cases

This paper reports the treatment of oral lymphangiomas with carbon dioxide CO₂ Laser. Lymphangiomas are rare congenital lymphatic malformations. These lesions are most frequently diagnosed during childhood, are most commonly located in the head and neck region, and are extremely rare in the oral cavity. Oral lymphangiomas are of complex treatment due to the difficulty in performing a complete excision. CO₂ laser is the most often used laser in the oral cavity due to its affinity with water and high absorption by the oral mucosa. Several benefits of the use of CO₂ laser have been reported for surgical oral procedures. The cases reported herein were biopsy-proven lymphangiomas of the oral cavity. The surgical procedures were carried out under local anesthesia and a focused CO₂ laser beam (λ10.600 nm, Φ ~2 mm, CW/RSP) was used. At the end of the surgery, the laser beam was used on a defocused mode to promote better hemostasis. Neither sutures nor dressings were used after surgery. No medication and only mouthwashes were prescribed to all patients on the postoperative period. There were no postsurgical complaints from the patients and no relapses of the conditions were observed after follow-up periods of 12 and 18 months. The use of CO₂ laser was practical, easy to carry out and effective on the treatment of oral lymphangiomas, with no lesion recurrence.

Use of laser fluorescence in dental caries diagnosis: a fluorescence x biomolecular vibrational spectroscopic comparative study

The aim of this work was to verify the existence of correlation between Raman spectroscopy readings of phosphate apatite (~960 cm-1), fluoridated apatite (~575 cm-1) and organic matrix (~1450 cm-1) levels and Diagnodent® readings at different stages of dental caries in extracted human teeth. The mean peak value of fluorescence in the carious area was recorded and teeth were divided in enamel caries, dentin caries and sound dental structure. After fluorescence readings, Raman spectroscopy was carried out on the same sites. The results showed significant difference (ANOVA, p<0.05) between the fluorescence readings for enamel (16.4 ± 2.3) and dentin (57.6 ± 23.7) on carious teeth. Raman peaks of enamel and dentin revealed that ~575 and ~960 cm-1 peaks were more intense in enamel caries. There was significant negative correlation (p<0.05) between the ~575 and ~960 cm-1 peaks and dentin caries. It may be concluded that the higher the fluorescence detected by Diagnodent the lower the peaks of phosphate apatite and fluoridated apatite. As the early diagnosis of caries is directly related to the identification of changes in the inorganic tooth components, Raman spectroscopy was more sensitive to variations of these components than Diagnodent.

Effects of LLLT on malignant cells: study in vitro

In addition to our previous report on the effects of LLLT on the proliferation of laryngeal carcinoma cells in which it was found that irradiation H.Ep.2 cells with 670nm laser results in increased cell proliferation, ti was decided to evaluate the effect of increased does of laser light. The aim of this study was to assess the effect off 635 and 670 nm laser irradiation of H.Ep.2 cells in vitro using MTT. The cells, obtained from SCC of the larynx, were routinely processed from defrost to the experimental condition. The cultures were kept either at 5 or 10 percent of FBS. Twenty- four hours after transplantation, the cells were irradiated with laser light at local light doses between 0.04 and 4.8 X 104 Jm-2. For 670 nm, significant differences in the proliferation were observed between the two concentrations of FBS and between irradiated cultures and controls. Although the results were not significant, 635 nm irradiated cells also proliferated more than non- irradiated ones. This occurred under both conditions of nutrition. It is concluded, that irradiation with 670 nm laser light applied at doses between 0.04 and 4.8 X 104 Jm-2 could significantly increase proliferation of laryngeal cancer cells.

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.

Caries diagnosis using laser fluorescence

Caries prevention is a goal to be achieved by dentist in order to promote health. There are several methods used to detect dental caries each one presenting advantages and disadvantages, especially regarding hidden occlusal caries. The improvement of laser technology has permitted the use of laser fluorescence for early diagnosis of hidden occlusal caries. The aim of this study was to assess the efficacy of the use of 655 nm laser light on the detection of hidden occlusal caries. Forty molar teeth from patients of both sexes which ages ranging from 10 - 18 years old were used on this study. Following manufactures instructions regarding the use of the equipment, the teeth had their occlusal surface examined with the DIAGNOdent. Twenty six of 40 teeth had hidden occlusal caries detected by the DIAGNOdent. However only 17 of these 26 teeth showed radiographic signs of caries the other 9 teeth showed no radiological signs of the lesion. Radiographic examination was able to identify 34,61% of false negative cases. This means that many caries would be left untreated due to the lack of diagnosis using both visual and radiographic examination. The use of the DIAGNOdent was effective in successfully detecting hidden occlusal caries.