BACKGROUND AND OBJECTIVE

Orthodontic brackets predispose dental biofilm accumulation causing caries and gingivitis. Chlorhexidine is an adjunct to mechanical plaque removal, but has side-effects (tooth staining, bacterial resistance) due to long term use. This study tested the efficacy of Photodynamic Therapy, which produces reactive oxygen species, to reduce Streptococcus mutans in dental biofilm on orthodontic brackets.

METHODS

A 5-day S. mutans biofilm was grown on forty enamel-bracket specimens. Thirty-nine specimens were randomized to three treatment groups: A. Distilled Water; B. 0.12% Chlorhexidine (CHX); C. Photodynamic Therapy (PDT) using Toluidine Blue O (TBO) as a photosensitizer, activated by red LED (630nm). After treatment, one random specimen from each group was viewed under Environmental Scanning Electron Microscopy (ESEM); the other 12 specimens, biofilms were collected, weighed, and cultured onto BHI agar plates to determine the number of CFU/mg. For baseline evaluation, one clean and one untreated specimens were preserved for ESEM.

RESULTS

Based on Tukey HSD test, group A had the most S. mutans (37.0573 CFU/mg) and was significantly different (pCONCLUSION

Both Photodynamic Therapy and 0.12% Chlorhexidine showed a significant reduction of S. mutans in dental biofilm on orthodontic brackets. However, there is no significant difference between them in reducing S. mutans CFU/mg. Photodynamic therapy could be an alternative adjunctive tool to mechanical removal of plaque adhered to orthodontic brackets.

Bacteria ; Photochemotherapy ; Photodynamic Therapy ; Microscopy, Electron, Scanning ; Biofilms ; Orthodontic Brackets ; Chlorhexidine

The mutagenic effect of HpD on cell SCE and the reactions of cell SCE to different sources of light combined with HpD were studied using V79 cells. There were 6 doses of HpD: 1 microgram/ml, 3 micrograms/ml, 5 micrograms/ml, 10 micrograms/ml, 50 micrograms/ml and 100 micrograms/ml. The dose of 5 micrograms/ml is equal to the maximum dose of HpD used in the clinic (HpD per milliliter of patient's blood). Our experiments demonstrated that when the cells were cultured in the dark and HpD was added to the medium no more than 5 micrograms/ml, the SCE frequencies were not increased. The cells were irradiated with different sources of light without HpD, both the fluorescence and ultraviolet light could promote SCE but the light of daylight lamp and red light did not increase it. But when HpD was added into culture medium at the dose of less than 5 micrograms/ml, every light could increase the cell SCE intensively except the daylight lamp light. The red light was more notable than the others by relation analysis.
Cells, Cultured ; Fluorescence ; Hematoporphyrin Photoradiation ; Hematoporphyrins ; pharmacology ; Humans ; Light ; Photochemotherapy ; Sister Chromatid Exchange ; drug effects ; Ultraviolet Rays

Cancer, as a serious threat to human health, is one of the major killers. The treatment of cancer has attracted more and more attention. Currently, the means of treating cancer is also increasing, but there is no emergence of a fully satisfactory treatment. A combination of sonodynamic therapy (SDT) and photodynamic therapy (PDT), named sono-photodynamic therapy (S-PDT), is a new composite cancer therapy. Because the therapy can significantly improve the tumor curing effect, it has good application prospects in cancer prevention and treatment. The present article reviewed the progress of the anti-tumor mechanisms and influencing factors of S-PDT.
Animals ; Antineoplastic Agents ; administration & dosage ; Combined Modality Therapy ; Hematoporphyrin Derivative ; administration & dosage ; Hematoporphyrin Photoradiation ; Humans ; Neoplasms ; drug therapy ; therapy ; Photochemotherapy ; methods ; Photosensitizing Agents ; administration & dosage ; Ultrasonic Therapy ; methods

While photodynamic therapy is applied on neoplasm, photosensitisers tend to accumulate in neoplastic tissues. With appropriate wavelength light, it causes photochemical reaction and destructs neoplastic tissues. Its better selection for tumor tissue with effective photochemical reaction, and lower side effect make it widespread application in gynecologic oncology. At present, photodynamic therapy has been used in diagnosing and treating lower genital tract carcinoma in situ, and advanced malignant tumor such as vulval and ovarian carcinoma.
Female ; Genital Neoplasms, Female ; drug therapy ; Hematoporphyrin Derivative ; therapeutic use ; Hematoporphyrin Photoradiation ; Humans ; Ovarian Neoplasms ; drug therapy ; Photochemotherapy ; Photosensitizing Agents ; therapeutic use ; Uterine Cervical Neoplasms ; drug therapy

OBJECTIVETo investigate biological effect of hematoporphyrin derivative (HpD) photodynamic therapy (PDT) on in vitro cultured nasopharyngeal carcinoma (NPC) cell lines CNE2 and C666-1.

METHODSCNE2 and C666-1 cells cultured in vitro were incubated in a medium containing HpD at different concentrations (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 microg/ml) for 4 h followed by exposure to different light doses (2, 5, 10, and 20 J/cm2) using a diode laser at 630 nm with power density of 20 mW/cm2. After 24 h of incubation with HpD-PDT, the survival rate of CNE2 and C666-1 cells were analyzed by MTT assay.

RESULTSHpD-PDT produced effective killing of CNE2 and C666-1 cells cultured in vitro, and the killing effects were positively correlated with HpD concentration and the irradiation dose. Exposure of CNE2 and C666-1 cells to irradiation dose of 20 J/cm2 resulted in the IC50 of 0.7 and 1.2 microg/ml, respectively (P<0.01). With the same HpD concentration and irradiation dose, the survival rate of C666-1 cells, however, was significantly higher than that of CNE2 cells (P<0.05).

CONCLUSIONHpD-PDT may result in effective killing of CNE2 and C666-1 cells cultured in vitro, although C666-1 cells are less sensitive to HpD-PDT than CNE2 cells.

Antineoplastic Agents ; pharmacology ; Cell Line, Tumor ; Cell Survival ; drug effects ; radiation effects ; Dose-Response Relationship, Drug ; Dose-Response Relationship, Radiation ; Hematoporphyrin Derivative ; pharmacology ; Hematoporphyrin Photoradiation ; methods ; Humans ; Nasopharyngeal Neoplasms ; pathology ; Photochemotherapy ; methods ; Photosensitizing Agents ; pharmacology

No abstract available.
Photochemotherapy* ; Porokeratosis*

The effects of photodynamic therapy (PDT) on the 180-sarcom tumors in some days after treatment were studied at the photo microscope and electro-microscope levels in BALB/c mice bearing 180 sarcom tumors. Animals received intravenous injection of 10 mg/kg of Photofrin and 24h later tumors were treated with 200-350 J/cm2 gold vapor laser light (630 nm). Animals were sacrificed and their tumors removed at time 24, 48, 72h and 7, 14, 21 days after PDT. The results indicated the effects of destruction of the 180-sarcom cells
Neoplasms ; Photochemotherapy

No abstract available.
Photochemotherapy ; Porokeratosis

Photodynamic therapy (PDT) is a promising new modality that utilizes the combination of a photosensitizing chemical and visible light for the management of various solid malignancies, including gastrointestinal (GI) cancer. PDT has some advantages over chemotherapy in terms of its greater safety and lower toxicity in the treatment of malignant lesions. However, PDT has not been used widely for treating upper GI cancer due to its relatively low cost-effectiveness and anatomical characteristics of the GI system. Nevertheless, PDT may be an effective alternative therapy for early upper-GI cancer patients who are at a high risk of curative surgical resection or systemic chemotherapy. In some clinical studies, PDT for various upper GI cancer showed positiveresults. To improve the efficacy of PDT for upper GI cancer, development of photosensitezer and light delivery system is needed.
Humans ; Light ; Photochemotherapy ; Triazenes

No abstract available.
Carcinoma, Basal Cell* ; Photochemotherapy*