BODIPY precursors and their cyclotriphosphazene Derivatives: Synthesis, photochemical properties and their application in PDT.

Photodynamic therapy (PDT) is a treatment method consisting of common combination of oxygen, light energy and a light absorbing molecule called a photosensitizer. In this work, four new compounds consisting of BODIPY precursors and BODIPY-cyclotriphosphazene derivatives were synthesized to investigate the PDT effects. The chemical structures of the compounds were characterized and then their photophysical properties were determined by spectroscopic techniques. The precursor BODIPYs and their cyclotriphosphazene derivatives exhibited similar properties such as strong absorption intensity, high photostability and low fluorescence profile in the NIR region. Additionally, the singlet oxygen production capacities of these compounds were determined using the photobleaching technique of 1,3-diphenylisobenzofuran (DPBF) under light illumination. By introducing iodine atoms into the molecule, which are responsible for the intersystem transition (ISC) enhancement, a more efficient singlet oxygen production was achieved in both the iodinated-BODIPY and its cyclotriphosphazene derivative. Anticancer activities of the precursor BODIPYs and their cyclotriphosphazene derivatives in the absence and presence of light illumination were evaluated on cancerous cell lines (PC3 and DU145) and non-tumorigenic prostate epithelial PNT1a cell. The compounds triggered the death of cancer cell PC3 the more significantly in the presence of red light compared to the healthy cells (PNT1a).

Effect of tooth discolouration severity on the efficacy and colour stability of two different trayless at-home bleaching systems.

Background. The use of trayless at-home bleaching agents in darker teeth is raising some concerns due to their unknown efficacy. The purpose of this in vitro study was to evaluate the effect of tooth discolouration severity on the efficacy and colour stability of two different trayless at-home bleaching systems. Methods. Ninety enamel-dentin samples were divided into two groups: lighter tand darker teeth. The teeth in each group were further divided into three groups (n=15): (1) tray-based system with 10% carbamide peroxide (Opalescence Oh) (control group); (2) a tray applied whitening membrane with 10% hydrogen peroxide (Treswhite Supreme); and (3) a whitening pen with 22% carbamide peroxide (Hollywood Smiles). After bleaching, the teeth were stained for 9 days using red wine. Colour readings before bleaching treatment were determined using a dental spectrophotometer and were repeated 24 h after bleaching treatment and 24 h after staining process. Analysis of variance, Bonferroni and Dunnett C tests were used at 5% significance level. Results. No differences were observed between the bleaching efficacy of Treswhite Supreme and Opalescence Oh in the lighter teeth, while Opalescence Oh had the best bleaching efficacy in the darker teeth (p<0.05). Hollywood Smiles had the worst bleaching efficay but the best color stability in both lighter and darker teeth (p<0.05). No differences were observed between the color stability values of Treswhite Supreme and Opalescence Oh. Conclusion. This study suggested that both the tooth discolouration severity and the type of trayless system used affected the bleaching efficacy, whereas only the type of trayless system affected the color stability.

Radiopacity evaluation of contemporary resin composites by digitization of images.

OBJECTIVE: The aim of this study was to evaluate the radiopacity of different composite resins and compare the values to those of human enamel and dentine. MATERIALS AND METHODS: Five specimens of each material with thicknesses of 2 mm were prepared and radiographed alongside aluminum step wedge and human enamel and dentin. Three occlusal radiographs for each material were taken and digitized using a desktop scanner. Mean gray values of the test materials were measured using Image J software. Then a conversion was performed according to establish the radiopacity of the test materials, in millimeters of equivalent Al. Data were analyzed using one-way analysis of variance and Duncan multiple range tests (P < 0.05). RESULTS: The radiopacity values varied among the restorative materials (P < 0.05). The radiopacity values of the materials tested were, in decreasing order: Enamel Plus HRI > Z250 > Filtek Ultimate ≥ Z550 > Nexcomp ≥ Nanoceram Bright > enamel ≥ Estelite Sigma Quick > Clearfil Majesty Esthetic ≥ Reflexions XLS ≥ Aelite LS Posterior ≥ dentin ≥ 2 mm Al. CONCLUSION: All resin composite materials investigated in this study presented different radiopacity values. However, all materials had radiopacity values greater than dentin and had sufficient radiopacity to meet International Organization for Standardization 4049 standard.

clinical evaluation of enamel microabrasion for the aesthetic management of mild-to-severe dental fluorosis.

STATEMENT OF THE PROBLEM: The clinical performance of enamel microabrasion alone for aesthetic management of dental fluorosis is debatable. PURPOSE OF THE STUDY: This study aimed to compare the clinical efficacy of enamel microabrasion for the aesthetic management of mild-to-severe dental fluorosis. METHODS/MATERIALS: A total of 154 fluorosed incisors and canines in 14 patients on the basis of the fluorosis were included; the teeth were classified as mild (group I, n = 53), moderate (group II, n = 56), and severe (group III, n = 45). All teeth were treated with enamel microabrasion (Opalustre, Ultradent Products, South Jordan, UT, USA). "Improvement in appearance," "changes in brown stains," "changes in opaque white areas," and "requirement for further treatments" were assessed by using visual scale systems. The data were analyzed using nonparametric tests (α = 0.05). RESULTS: The "improvement in appearance" score was the worst for group III (p < 0.05), whereas the "changes in opaque white areas" score was the best for group I (p < 0.05). Groups II and III did not differ with respect to "changes in brown stains." The proportion of patients who needed further treatment was the highest in Group III (p < 0.05). CONCLUSIONS: The severity of fluorosis affected the clinical performance of enamel microabrasion except for its performance of removing brown stains. Increase in fluorosis severity led to increased requirements for further treatments. CLINICAL SIGNIFICANCE: The clinical performance of enamel microabrasion is affected by the severity of dental fluorosis, except for its performance of removing brown stains. Even though its performance of improving appearance decreases with the increase in severity of fluorosis, it may not only remove the fluorosis stains but also may increase the success of additional subsequent treatment.

A minimally invasive technique for the management of severely fluorosed teeth: A two-year follow-up.

OBJECTIVE: Severely fluorosed and heavily discolored teeth that have large enamel defects give rise to esthetic concerns and require permanent treatment. In such cases, restorative techniques such as porcelain or composite laminate veneers or crowns are generally preferred, in which tooth preparation is inevitably required. MATERIALS AND METHODS: This clinical report describes a patient with severely fluorosed teeth who was successfully treated with a minimally invasive technique including enamel microabrasion (6.6% hydrochloric acid slurry with silicon carbide micro-particles, Opalustre, Ultradent Products, Inc., South Jordan, UT, USA) followed by in-office bleaching (38% hydrogen peroxide, Opalescence Boost, Ultradent). Enamel microabrasion was conducted in two visits while three visits were required for in-office bleaching. Patient was followed-up after 2 years. RESULT: A slight staining had occurred during this period, but it was acceptable for patient. No adverse effects were observed. CONCLUSIONS: The minimally invasive technique including enamel microabrasion and in-office bleaching was efficient and may represent a good alternative to traditional restorative techniques for the management of severely fluorosed teeth.