Photofrin® was first approved in the 1990s as a sensitizer for use in treating cancer via photodynamic therapy (PDT). Since then a wide variety of dye sensitizers have been developed and a few have been approved for PDT treatment of skin and organ cancers and skin diseases such as acne vulgaris. Porphyrinoid derivatives and precursors have been the most successful in producing requisite singlet oxygen, with Photofrin® still remaining the most efficient sensitizer (quantum yield = 0.89) and having broad food and drug administration (FDA) approval for treatment of multiple cancer types. Other porphyrinoid compounds that have received approval from US FDA and regulatory authorities in other countries include benzoporphyrin derivative monoacid ring A (BPD-MA), meta-tetra(hydroxyphenyl)chlorin (m-THPC), N-aspartyl chlorin e6 (NPe6), and precursors to endogenous protoporphyrin IX (PpIX): 1,5-aminolevulinic acid (ALA), methyl aminolevulinate (MAL), hexaminolevulinate (HAL). Although no non-porphyrin sensitizer has been approved for PDT applications, a small number of anthraquinone, phenothiazine, xanthene, cyanine, and curcuminoid sensitizers are under consideration and some are being evaluated in clinical trials. This review focuses on the nature of PDT, dye sensitizers that have been approved for use in PDT, and compounds that have entered or completed clinical trials as PDT sensitizers.

https://www.mdpi.com/1996-1944/6/3/817/pdf

Dye Sensitizers for Photodynamic Therapy.

Recent advances in BMP receptor signaling

Direct comparison of the bond strength results of the different test methods: A critical literature review

OBJECTIVES
Resin-based dental materials are not inert in the oral environment, and may release components, initially due to incomplete polymerization, and later due to degradation. Since there are concerns regarding potential toxicity, more precise knowledge of the actual quantity of released eluates is necessary. However, due to a great variety in analytical methodology employed in different studies and in the presentation of the results, it is still unclear to which quantities of components a patient may be exposed. The objective of this meta-analytical study was to review the literature on the short- and long-term release of components from resin-based dental materials, and to determine how much (order of magnitude) of those components may leach out in the oral cavity.


METHODS
Out of an initial set of 71 studies, 22 were included. In spite of the large statistical incertitude due to the great variety in methodology and lack of complete information (detection limits were seldom mentioned), a meta-analytical mean for the evaluated eluates was calculated. To relate the amount of potentially released material components with the size of restorations, the mean size of standard composite restorations was estimated using a 3D graphical program.


RESULTS
While the release of monomers was analyzed in many studies, that of additives, such as initiators, inhibitors and stabilizers, was seldom investigated. Significantly more components were found to be released in organic than in water-based media. Resin-based dental materials might account for the total burden of orally ingested bisphenol A, but they may release even higher amounts of monomers, such as HEMA, TEGDMA, BisGMA and UDMA. Compared to these monomers, similar or even higher amounts of additives may elute, even though composites generally only contain very small amounts of additives. A positive correlation was found between the total quantity of released eluates and the volume of extraction solution.


SIGNIFICANCE
There is a clear need for more accurate and standardized analytical research to determine the long-term release from resin-based materials. Several guidelines for standardization are proposed.

How much do resin-based dental materials release? A meta-analytical approach (vol 27 pg 723, 2011)

Statistical Methods in Agriculture and Experimental Biology.

Morphologic Texture Characterization Allied to Cigarette Smoke Increase Pigmentation in Composite Resin Restorations: CIGARETTE SMOKE STAINING

PURPOSE To evaluate the influence of two concentrations of bleaching agents applied over enamel surfaces on the dentin bonding at different depths. METHODS Twenty-four bovine incisors were sectioned, obtaining three fragments per tooth (4x4 mm). Each fragment presented a 0.7 mm enamel thickness; and the dentin thickness varied according to the experimental group: 0.5 mm, 1 mm or 1.5 mm. Fragments from each dentin-thickness were allocated into three groups (n=8): G1: Control (no bleaching); G2: 16% carbamide peroxide (6 hours/14 days); G3: 35% hydrogen peroxide (three 15-minute treatments). 24 hours after enamel bleaching, the adhesive system was applied and dentin surfaces were restored with resin composite cylinders (2 mm diameter and 1 mm height). The micro-shear testing was performed immediately after restorative procedures, at a speed of 0.5 mm/minute until failure. Bond strength values, in MPa, were statistically analyzed (split-plot ANOVA/Tukey alpha=0.05). RESULTS Means obtained were: G1-0.5 mm: 13.5, G1-1 mm: 9.48, G1-1.5 mm: 9.01; G2-0.5 mm: 9.64, G2-1 mm: 9.44, G2-1.5 mm: 9.27; G3-0.5 mm: 11.68, G3-1 mm: 11.64, G3-1.5 mm: 7.63. Regardless of the dentin thickness, bleached groups presented bond strengths similar to that of control groups. Nevertheless, significant differences among dentin depths were detected (P=0.02); and the lowest bond strength was observed on the deepest dentin (1.5 mm). The diffusion of bleaching agents through enamel surfaces did not affect the bond strength to dentin, which is highly dependent on the morphology/depth of the substrate.

Effect of the diffusion of bleaching agents through enamel on dentin bonding at different depths.

The aim of this study was to evaluate the degree of conversion (DC) of two composite resins with different shades that were light cured by light-emitting diodes (LEDs) of different irradiances. Specimens (5 mm ' 2 mm) were prepared with a nanofilled (Filtek Supreme - A2E, A2D, and WE) or microhybrid resin (Opallis - A2E, A2D, and EBleach Low) and were randomly divided into 12 groups (n = 5 each) according to the composite resin and light-curing unit (Elipar FreeLight 2, 1250 mW/cm²; Ultralume 5, 850 mW/cm²). After 24 h, the DC was measured on two surfaces (top and bottom) with Fourier Transform infrared spectroscopy (FTIR). Data were statistically analyzed with two-way ANOVA and Tukey test (a = 0.05). Statistical differences among the surfaces were observed in all experimental conditions, with higher values on the top surface. The microhybrid resin presented the highest DCs for shades A2E and A2D on the top surface. The LED with higher irradiance promoted better DCs. Taken together, the data indicate that the shade of a composite resin and the irradiance of the light source affect the monomeric conversion of the restorative material.

/pdf/influence-of-different-shades-and-led-irradiance-on-the-2qtpbzp5p7.pdf

Influence of different shades and LED irradiance on the degree of conversion of composite resins

This brief review discusses the role of occlusal interferences on the development and progression of temporomandibular dysfunction (TMD) and postural disorders. The eligible literature is described and critically presented to demonstrate that occlusal interferences are an important factor in the risk of TMD. Several studies have demonstrated through their findings that the use of occlusal adjustments, whether or not associated with restorative procedures, might avoid the development of articular problems in vulnerable patients. The occlusal interferences caused by restorative procedures or orthodontic treatment can cause TMDs in susceptible patients, and occlusal adjustments can be an alternative in the treatment of these TMDs.

/pdf/occlusal-interferences-how-can-this-concept-influence-the-3fl7eiixe6.pdf

Occlusal interferences: how can this concept influence the clinical practice?

Clinical Relevance New resin composite technologies, such as nano-filled-based systems, have been developed. The assessment of such materials in a simulated laboratory chewing condition may assist with the selection of composites in a clinical situation.

Andrea Nóbrega Cavalcanti

Papers

Morphologic Texture Characterization Allied to Cigarette Smoke Increase Pigmentation in Composite Resin Restorations: CIGARETTE SMOKE STAINING

Effect of the diffusion of bleaching agents through enamel on dentin bonding at different depths.

Influence of different shades and LED irradiance on the degree of conversion of composite resins

Occlusal interferences: how can this concept influence the clinical practice?

Effect of cyclic loading on the bond strength of class II restorations with different composite materials.