Jean Nunes dos Santos

Odontogenic tumors: analysis of 127 cases

One hundred and twenty-seven cases of histologically confirmed odontogenic tumors were retrieved from a total of 5,289 oral and maxillary lesions diagnosed at the Division of Oral Pathology, Federal University of Rio Grande do Norte, during a period of 30 years (1970-1999). The most common histological diagnosis was odontoma (50.40%), followed by ameloblastoma (30.70%). The prevalence of odontogenic tumors was greater in females and the peak incidence occurred in the second and third decades of life. The main anatomical location was the mandible, and no malignant tumors were found.

Effectiveness of Laser Photobiomodulation at 660 or 780 Nanometers on the Repair of Third-Degree Burns in Diabetic Rats

OBJECTIVE The aim of this investigation was to compare by light microscopy the effects of laser photobiomodulation (LPBM) at lambda = 660 nm and lambda = 780 nm on third-degree burns in diabetic Wistar rats. BACKGROUND DATA Burns are severe injuries that result in fluid loss, tissue destruction, infection, and shock, that may result in death. Diabetes is a disease that reduces the bodys ability to heal properly. LPBM has been suggested as an effective method of improving wound healing. MATERIALS AND METHODS A third-degree burn measuring 1.5 x 1.5 cm was created in the dorsum of each of 55 animals, and they were divided into three groups that were or were not treated with LPBM (lambda = 660 nm or lambda = 780 nm, 35 mW, varphi = 2 mm, 20 J/cm(2)). The treatments were started immediately post-burn at four points within the burned area (5 J/cm(2)) and were repeated at 24-hour intervals over 21 d. The animals were humanely killed after 3, 5, 7, 14, and 21 d by an overdose of intraperitoneal general anesthetic. The specimens were routinely cut and stained and analyzed by light microscopy. RESULTS We found that healing in the animals receiving 660-nm laser energy was more apparent at early stages, with positive effects on inflammation, the amount and quality of granulation tissue, fibroblast proliferation, and on collagen deposition and organization. Epithelialization and local microcirculation were also positively affected by the treatment. CONCLUSION The use of 780-nm laser energy was not as effective as 660-nm energy, but it had positive effects at early stages on the onset and development of inflammation. At the end of the experimental period the primary effect seen was on the amount and quality of the granulation tissue. The 660-nm laser at 20 J/cm(2), when used on a daily basis, was more effective than the 780-nm laser for improving the healing of third-degree burns in the diabetic rats beginning at the early stages post-burn.

Does the Use of Laser Photobiomodulation, Bone Morphogenetic Proteins, and Guided Bone Regeneration Improve the Outcome of Autologous Bone Grafts? An in Vivo Study in a Rodent Model

OBJECTIVE The aim of the present investigation was to histologically assess the effect of laser photobiomodulation (LBPM) on the repair of autologous bone grafts in a rodent model. BACKGROUND DATA A major problem in modern dentistry is the recovery of bone defects caused by trauma, surgical procedures, or pathologies. Several types of biomaterials have been used to improve the repair of these defects. These materials are often associated with procedures of guided bone regeneration (GBR). MATERIALS AND METHODS Twenty four animals were divided into four groups: group I (control); group II (LPBM of the bone graft); group III (bone morphogenetic proteins [BMPs] + bone graft); and group IV (LPBM of the bed and the bone graft + BMPs). When appropriate the bed was filled with lyophilized bovine bone and BMPs used with or without GBR. The animals in the irradiated groups received 10 J/cm(2) per session divided over four points around the defect (4 J/cm(2)), with the first irradiation immediately after surgery, and then repeated seven times every other day. The animals were humanely killed after 40 d. RESULTS The results showed that in all treatment groups, new bone formation was greater and qualitatively better than the untreated subjects. Control specimens showed a less advanced repair after 40 d, and this was characterized by the presence of medullary tissue, a small amount of bone trabeculi, and some cortical repair. CONCLUSION We conclude that LPBM has a positive biomodulatory effect on the healing of bone defects, and that this effect was more evident when LPBM was performed on the surgical bed intraoperatively, prior to the placement of the autologous bone graft.

A Comparative Study of the Effects of Laser Photobiomodulation on the Healing of Third-Degree Burns: A Histological Study in Rats

OBJECTIVE The aim of this investigation was to compare by light microscopy the effects of laser photobiomodulation at wavelengths of 660 and 780 nm on third-degree burns in Wistar rats. BACKGROUND DATA Burns are severe injuries that result in the loss of fluid and destruction of tissue, infection, and shock that may result in death. Laser energy has been suggested as an effective method to improve wound healing. MATERIALS AND METHODS Fifty-five animals were used in this study. A third-degree burn measuring 1.5 x 1.5 cm was created on the dorsum of each animal. The animals were divided into three subgroups according the type of laser photobiomodulation they received (wavelength of 660 or 780 nm, 35 mW, theta = 2 mm, and 20 J/cm2). In the animals receiving treatment, it was begun immediately post-burn at four points around the burn (5 J/cm2) and repeated at 24-h intervals for 21 d. The animals were humanely killed after 3, 5, 7, 14, and 21 d by an intraperitoneal overdose of general anesthetic. The specimens were routinely cut and stained, and then were analyzed by light microscopy. RESULTS The results showed more deposition of collagen fibers, larger amounts of granulation tissue, less edema, a more vigorous inflammatory reaction, and increased revascularization on all laser-treated animals. These features were more evident at early stages when the 660-nm laser was used, and were more evident throughout the experimental period for the animals receiving 780-nm laser therapy. CONCLUSION We concluded that laser photobiomodulation using both wavelengths improved healing of third-degree burns on Wistar rats.

Altered cytokeratin expression in actinic cheilitis

Background:  Actinic cheilitis (AC) is a widely recognized precancerous lesion of the lip. Varying degrees of epithelial dysplasia may be present. However, no studies have correlated epithelial changes with cytokeratin expression that might reflect the disordered maturation that is probably occurring.

Effect of LED Phototherapy of Three Distinct Wavelengths on Fibroblasts on Wound Healing: A Histological Study in a Rodent Model

AIM The aim of the present investigation was to evaluate histologically fibroblastic proliferation on dorsal cutaneous wounds in a rodent model treated or not with light-emitting diodes (LEDs) of three wavelengths. BACKGROUND Fibroblasts secrete substances essential for wound healing. There are few reports of LED phototherapy on fibroblast proliferation, mainly in vivo. ANIMALS AND METHODS Following approval by the Animal Experimentation Committee of the School of Dentistry of the Federal University of Bahia, we obtained 16 young adult male Wistar rats weighing between 200 and 250 g. Under general anesthesia, one excisional wound was created on the dorsum of each animal; they were then randomly distributed into four groups of four animals each: G0, untreated control; G1, red LED (700 +/- 20 nm, 15 mW, 10 J/cm(2)); G2, green LED (530 +/- 20 nm, 8 mW, 10 J/cm(2)); and G3, blue LED (460 +/- 20 nm, 22 mW, 10 J/cm(2)). The irradiation started immediately after surgery and was repeated every other day for 7 days. Animals were killed 8 days after surgery. The specimens were removed, routinely processed to wax, cut, and stained with hematoxylin/eosin (HE). Fibroblasts were scored by measuring the percentage of these cells occupying the area corresponding to wound healing on stained sections. RESULTS The quantitative results showed that red LED (700 +/- 20 nm) and green LED (530 +/- 20 nm) showed a significant increase in fibroblast numbers (p < 0.01 and p = 0.02) when compared with the control group. CONCLUSION The use of green and red LED light is effective in increasing fibroblastic proliferation on rodents.

Light microscopic description of the effects of laser phototherapy on bone defects grafted with mineral trioxide aggregate, bone morphogenetic proteins, and guided bone regeneration in a rodent model

We carried out a histological analysis on bone defects grafted with mineral trioxide aggregate (MTA) treated or not with laser, bone morphogenetic protein (BMP), and guided bone regeneration (GBR). Benefits of the use of MTA, laser, BMPs, and GBR on bone repair are well known, but there is no report on their association with laser light. Ninety rats were divided into 10 groups each subdivided into 3. Defects on G II and I were filled with the blood clot. G II was further irradiated with LED. G III and IV were filled with MTA; G IV was further irradiated with laser. G V and VI, the defects filled with MTA and covered with a membrane (GBR). G VI was further irradiated with laser. G VII and VIII, BMPs were added to the MTA and group VIII further irradiated with laser. G IX and X, the MTA + BMP graft was covered with a membrane (GBR). G X was further irradiated with laser. Laser light (λ = 850 nm, 150 mW, 4 J/cm(2) ) was applied over the defect at 48-h intervals and repeated for 15 days. Specimens were processed, cut and stained with H&E and Sirius red and underwent histological analysis. Subjects on group X were irradiated. The results showed different tissue response on all groups during the experimental time. Major changes were seen on irradiated subjects and included marked deposition of new bone in advanced maturation. It is concluded that near infrared laser phototherapy improved the results of the use of the MTA on bone defects.

Influence of the Combination of Infrared and Red Laser Light on the Healing of Cutaneous Wounds Infected by Staphylococcus aureus

AIM We aimed to assess the use of two wavelengths on the healing of infected wounds. BACKGROUND Infection is the most significant cause of impaired wound repair or healing. Several therapeutic approaches are used for improving wound healing including the use of different light sources, such as the laser. Some wavelengths yield positive photobiological effects on the healing process. MATERIAL AND METHODS The backs of 24 young adult male Wistar rats under general anesthesia were shaved and cleaned, and a 1 by 1 cm cutaneous wound was created with a scalpel and left untreated. The wounds were infected with Staphylococcus aureus, and the rats were randomly divided into two sets of four subgroups with three animals in each subgroup: control, red laser light, infrared laser light, and red + infrared laser light. Laser phototherapy was carried out with a diode [λ680 nm/790 nm, power (P) = 30 mW/40 mW, continuous wave laser, Ø = 3 mm, power density (P) = 424 and 566 mW/cm(2), time = 11.8/8.8 sec, E = 0.35 J] and started immediately after surgery and repeated every other day for 7 d. Laser light was applied on four points around the wounded area (5 J/cm(2)). The animals were killed either 8 or 15 d after contamination. Specimens were taken, embedded in paraffin, and sectioned and stained for histological analysis. RESULTS Histological analysis showed that control subjects had a lower amount of blood vessels when compared with irradiated subjects. Irradiated subjects had more advanced resolution of inflammation compared with controls. Irradiated subjects also showed a more intense expression of the collagen matrix. The collagen fibers were mostly mature and well organized in these subjects at the end of the experimental time especially when both wavelengths were used. CONCLUSION The results of the present study indicate that laser phototherapy has a positive effect on the healing of infected wounds, particularly with the association of λ680 + λ790 nm.

Secretome profiling of oral squamous cell carcinoma-associated fibroblasts reveals organization and disassembly of extracellular matrix and collagen metabolic process signatures

An important role has been attributed to cancer-associated fibroblasts (CAFs) in the tumorigenesis of oral squamous cell carcinoma (OSCC), the most common tumor of the oral cavity. Previous studies demonstrated that CAF-secreted molecules promote the proliferation and invasion of OSCC cells, inducing a more aggressive phenotype. In this study, we searched for differences in the secretome of CAFs and normal oral fibroblasts (NOF) using mass spectrometry-based proteomics and biological network analysis. Comparison of the secretome profiles revealed that upregulated proteins involved mainly in extracellular matrix organization and disassembly and collagen metabolism. Among the upregulated proteins were fibronectin type III domain-containing 1 (FNDC1), serpin peptidase inhibitor type 1 (SERPINE1), and stanniocalcin 2 (STC2), the upregulation of which was validated by quantitative PCR and ELISA in an independent set of CAF cell lines. The transition of transforming growth factor beta 1 (TGF-β1)-mediating NOFs into CAFs was accompanied by significant upregulation of FNDC1, SERPINE1, and STC2, confirming the participation of these proteins in the CAF-derived secretome. Type I collagen, the main constituent of the connective tissue, was also associated with several upregulated biological processes. The immunoexpression of type I collagen N-terminal propeptide (PINP) was significantly correlated in vivo with CAFs in the tumor front and was associated with significantly shortened survival of OSCC patients. Presence of CAFs in the tumor stroma was also an independent prognostic factor for OSCC disease-free survival. These results demonstrate the value of secretome profiling for evaluating the role of CAFs in the tumor microenvironment and identify potential novel therapeutic targets such as FNDC1, SERPINE1, and STC2. Furthermore, type I collagen expression by CAFs, represented by PINP levels, may be a prognostic marker of OSCC outcome.

Influence of Laser Phototherapy (λ660 nm) on the Outcome of Oral Chemical Carcinogenesis on the Hamster Cheek Pouch Model: Histological Study

PURPOSE This study aimed to evaluate, histologically, the effect of low-level laser therapy (LLLT) (λ660 nm) on DMBA chemically induced lesions of the oral mucosa of hamsters. BACKGROUND DATA Squamous cell carcinoma (SCC) is the most common neoplasm of the oral cavity. It is aggressive, highly proliferative, invasive, and metastatic. There is evidence that LLLT similarly affects neoplasic and non-neoplasic cells. METHODS Cancerous lesions were induced on the cheek pouch of 15 golden Syrian hamsters by using DMBA 3 times a week for 8 weeks. At the end of the cancer induction (8 weeks), animals in G1 were killed and the presence of tumors confirmed. Animals in G3 were irradiated (λ660 nm, 30 mW, CW, Ø=3 mm, area: 0.07 cm(2), 424 mW/cm(2), 133 sec, 56.4(2)J/ cm(2), 4J) at every other day for 4 weeks. G2 received no interventions for the same period. Samples were taken and underwent histological analysis by light microscopy. RESULTS GI showed 100% well-differentiated SCC. G2 showed 20% moderately differentiated and 80% well-differentiated SCC. G3 showed 40% well-differentiated, 40% poorly differentiated, and 20% moderately differentiated SCC. Significant differences (p=0.02) in the amount of well-differentiated SCC were seen between G1 and G3 and between G3 and G2 (p=0.04). Significant difference was also seen between G3 and G1 and G2 with regard to the amount of poorly differentiated tumors (p=0.04). CONCLUSIONS It is concluded that LLLT, within the parameters used in the present study, caused a significant progression of the severity of SCC in the oral cavity of hamsters.