Ultraviolet Radiation and Multiple Stressor Effects on Zebrafish Embryos -

Pelagic embryos of fish may be exposed to high doses of natural UV radiation. Shortwave UV, UVB, as well as UVA may penetrate the water column to depths of several meters. The penetration depth differs depending on the contents of particles, dissolved matter or pollutants. Pollutants may also interact photochemically with UV- and visible radiation.

Nytt fra NIOM: Retningslinjer for lysherding i odontologi -

I mai 2014 deltok NIOM på et symposium ved Dalhousie University, Halifax, Canada om lysherding i odontologi. Det var 40 deltakerne fra ulike akademiske miljø og industrien, som utarbeidet retningslinjer for klinisk relevant valg og bruk av herdelamper (1)

The influence of bis-EMA vs bis-GMA on the degree of conversion and water susceptibility of experimental composite materials -

The degree of conversion (DC) of mixtures with higher content of bis-EMA is affected by the presence of bis-GMA at lower energy density delivered from the curing device, suggesting that the restrictions caused by the presence of hydrogen bonds is dependent of the irradiation time used

Antibacterial phototoxic effects of synthetic asymmetric and glycosylated curcuminoids in aqueous formulations: studies on curcumin and curcuminoids. LIV. -

The aim of this study was to evaluate the in vitro phototoxic potential of synthetic asymmetric and glycosylated curcuminoids on planktonic model bacteria by counting the colony forming units.

Simulation of clinical fractures for three different all-ceramic crowns. -

Comparison of fracture strength and fracture modes of different all-ceramic crown systems is not straightforward. Established methods for reliable testing of all-ceramic crowns are not currently available. Published in-vitro tests rarely simulate clinical failure modes and are therefore unsuited to distinguish between the materials. The in-vivo trials usually lack assessment of failure modes. Fractographic analyses show that clinical crowns usually fail from cracks initiating in the cervical margins, whereas in-vitro specimens fail from contact damage at the occlusal loading point. The aim of this study was to compare three all-ceramic systems using a clinically relevant test method that is able to simulate clinical failure modes.

Formulation and characterisation of lyophilised curcumin solid dispersions for antimicrobial photodynamic therapy (aPDT) -

Curcumin is currently under investigation as a potential photosensitiser in antimicrobial photodynamic therapy (aPDT). Previous studies have demonstrated high phototoxicity towards Gram-positive (G+) bacteria, but lower effect on Gram-negative (G-) bacteria.

Photoinactivation of bacteria by lumichrome: Influence of formulation and preparation method. -

Lumichrome, a photodegradation product of riboflavin, is an endogenous compound in humans. The compound is more photostable and a more efficient photogenerator of singlet oxygen than riboflavin. It absorbs radiation in the UVA and blue light region, which can be an advantage in aPDT of superficial infections.

Formulation and characterization of lyophilized curcumin solid dispersions for antimicrobial photodynamic therapy (aPDT): Studies on curcumin and curcuminoids LII -

Bacterial resistance to antibiotics is increasing and alternative antibacterial treatments like antimicrobial photodynamic therapy (aPDT) are needed. Curcumin is under investigation as a potential photosensitizer in aPDT.

The effect of short curing time on chemical and mechanical properties of the composites -

The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps.

Biofilm formation on nanostructured hydroxyapatite-coated titanium. -

Biofilm formation on medical devices is a common cause of implant failure, especially regarding implants that breach the epithelial tissue, so-called transcutaneous implants. Nanotechnology and the development of new nanomaterials have given the opportunity to design nanotextured implant surfaces.

Leaching of monomers from bulk-fill composites -

This study investigated the leaching of monomers from bulk-fill composites, as well as some physical properties of the materials

Safe use of dental laser -

Laser is employed for a variety of tooth and oral treatments. Numbers from a national registry indicate that its use has doubled during the latest five years. This increase has occurred despite, in many instances, the lack of evidence of superior treatment outcome relative to conventional or other new treatments.

TEGDMA and filler particles from dental composites additively attentuate LPS-induced cytokine release from the macrophage cell line RAW 264.7 -

Due to incomplete curing and material degradation, cells in the oral cavity may be exposed to monomers and filler particles from dental composite fillings. The objective of the present study was to investigate if combined exposures to particles and a methacrylate monomer from composite fillings resulted in additive effects on the macrophage immune response.

Glass ionomer – a suitable restorative material in deciduous teeth? -

Traditionally, amalgam has been used for Class II restorations in primary teeth, but the use of amalgam has decreased in Scandinavia during the latest few decades, and now, amalgam has been banned in Norway and Sweden. Glass ionomer (GIC) adheres to tooth substance and has been a popular alternative to amalgam, but the traditional GIC products do not give as high longevity as amalgam in Class II restorations.

Fractures in dental ceramics: research and clinical experience -

The main problem with ceramics as biomaterials is that they are brittle. One focus of research and development has been on improving the materials’ fracture strength and thereby increasing the clinical success rates for dental, all-ceramic restorations. The most advanced dental ceramics should, according to in vitro testing, be able to withstand human mastication forces.

Cell toxicity of methacrylate monomers-the role of glutathione adduct formation. -

Polymer-based dental restorative materials are designed to polymerize in situ. However, the conversion of methacrylate monomer to polymer is never complete, and leakage of the monomer occurs. It has been shown that these monomers are toxic in vitro; hence concerns regarding exposure of patients and dental personnel have been raised.

Experimental investigation of the effect of surface roughness on bone-cement-implant shear bond strength. -

Debonding of cemented bone implants is regarded as a major contributor to complications. The relationship between shear bond strength and surface roughness has been investigated, however there are inconsistencies in the trends reported in different studies.

Summary of: Side effects of external tooth bleaching: a multi-centre practice-based prospective study. -

The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects.
Bleaching treatment, irrespective of method, caused a high prevalence of side effects

Solubility and strength of zirconia-based dental materials after artificial aging -

The purpose of this study was to compare the flexure strength of zirconium dioxide materials designed for different sintering techniques before and after surface exposure to an acidic solution and to correlate the dissolution of the materials with strength data.

Clinically relevant evaluation of fracture strength of all-ceramic crowns -

Determination of fracture strength of different all-ceramic dental crown systems is not straight forward. Most in vitrotest methods induce contact damage at the loading point (crunch the crown-tests). Clinical failures, on the other hand, usually originate from cracks in the cervical margins. The aim of this study was to compare three all-ceramic systems using a test method that mimic clinical failure modes.

Ex tempore prepared superstaurated solutions of curcumin intended for aPDT -

A naturally occurring photosensitizer Curcumin (Cur) has already shown good in vitro bacterial phototoxicity.¹ ²1,2  However,low aqueous solubility and poor photolytic and hydrolytic stability limit the therapeutic application of Cur in antibacterial photodynamic therapy (aPDT). The concept of supersaturation was explored for enhancing the photodynamic effect of Cur. A supersaturated solution of Cur has already demonstrated […]

Hyperspectral imaging/reflectance spectroscopy of mouse oral tissue exposed to high intensity blue light. -

Oral tissues are exposed to optical radiation during various dental treatments and diagnostic methods. However, adverse effects are seldom addressed. Hyperspectral imaging (HSI) and visible near-infrared reflection spectroscopy (VNIRS) were used to observe oral tissue changes in mice exposed to blue light with respect to erythema (erythema index; EI) and pigmentation (melanin index; MI). Pigmented mice (C57BL/6N; ngroup = 3) were exposed on the tongue and the abdominal skin for control or left unexposed. Irradiation was performed with an LED intended for photopolymerisation of dental materials (λpeaks: 409/460 nm) with irradiance ≈ 2 W/cm2 and radiant exposure ≈ 120 J/cm2.

Antimicrobial photodynamic treatment of oral infections -

The increased occurrence of antibiotic resistance in general necessitates development of alternative antimicrobial drugs or methods. Further, certain cases of periodontitis respond poorly to conventional treatment. The principle of photodynamic therapy, currently used against certain cancers, may be a practical treatment modality for oral infections, presumably with low possibility for development of resistance. The treatment requires the presence of light-absorbing molecules (photosensitizer; PS) and irradiation with a light source emission that spectrally matches the light-absorption of the PS.

Safety of optical light sources in the dental clinic -

To inform operators and suppliers of curing/bleaching lamps, lasers and other optical instruments intended for oral applications about safe use. Further, to give references to relevant international guidelines and standards.

Clinically relevant fracture testing of all-ceramic crowns -

Fracture strength measured in vitro indicates that most all-ceramic crowns should be able to withstand mastication forces. Nevertheless, fractures are one of the major clinical problems with all-ceramic restorations. Furthermore, the fracture mode of all-ceramic crowns observed in clinical use differs from that found in conventional fracture strength tests. The aim of the present study was to develop and investigate a method that simulates clinical fracture behavior in vitro

Detection of leachables and cytotoxicity after exposure to methacrylate- and epoxy-based root canal sealers in vitro. -

Abstract Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from […]

Biofilm formation on nanostructured hydroxyapatite-coated titanium -

Biofilm formation on medical devices is a common cause of implant failure, especially regarding implants that breach the epithelial tissue, so-called transcutaneous implants. Nanotechnology and the development of new nanomaterials have given the opportunity to design nanotextured implant surfaces. Such surfaces have been studied using various in vitro methods showing that nanosized features strongly benefit bone cell growth.

Effect of short LED lamp exposure on wear resistance, residual monomer and degree of conversion for Filtek Z250 and Tetric EvoCeram composites. -

The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times. This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps.

Surface modification of fiber reinforced polymer composites and their attachment to bone simulating material -

The purpose of this study was to investigate the effect of fiber orientation of a fiber-reinforced composite (FRC) made of poly-methyl-methacrylate (PMMA) and E-glass to the surface fabrication process by solvent dissolution. Intention of the dissolution process was to expose the fibers and create a macroporous surface onto the FRC to enhance bone bonding of the material

Osteoporosis and periodontal disease -

Primary osteoporosis signifies the loss of trabecular bone mass following menopause and is linked to decreased production of estrogen. The condition increases the risk of traumatic fractures of peripheral bones such as wrist or femur and compression fractures of the spine. The degree of osteoporosis is determined by assessing the mineral density of different skeletal bones. Jawbone, including the tooth supporting alveolar process, may also be affected by osteoporosis.

Supersaturation and supersaturated drug delivery systems to surpass the outher membrane barriers of Gram negative bacteria in antimicrobial photodynamic therapy (aPDT). -

Bacterial resistance towards antibiotics is increasing. Especially Gram negative (G-) pathogenic bacteria are responsible for serious nosocomial infections. Novel treatment strategies such as antimicrobial photodynamic therapy (aPDT) are needed to fight such infections.

Application of nanovehicles in preparations for antimicrobial photodynamic therapy (aPDT) -

Topical application is the preferred administration route of the photosensitizer (PS) in antimicrobial photodynamic therapy (aPDT), e.g. for the treatment of infections in the oral cavity or skin. The drug formulation should allow for a sufficient contact time between the preparation and tissue, a rapid release of PS, and a selective uptake of PS in bacteria.

Antibacterial effects of native and methacrylate modified chitosan -

Commercial resin-based composites are mainly composed of dimethacrylate-based monomers, such as triethyleneglycol dimethacrylate (TEGDMA), inorganic fillers and a coupling agent. Cured resinbased composites have no antibacterial effect against oral bacteria and half of all fillings replaced are because of new caries . Chitosan is a natural carbohydrate polymer derived from the deacetylation of chitin. Chitosan has been shown to have an inhibitor effect on the adherence of oral bacteria onto human tooth surfaces.

Dental monomers inhibit LPS-induced cytokine release from the macrophage cell line RAW264.7 -

Methacrylate monomers have been identified in aqueous extracts of freshly cured dental fillings. The hypothesis tested presently was that low concentrations of triethyleneglycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) alone or in combination interfere with the LPS-induced release of cytokines from the macrophage cell line RAW264.7.

Solid dispersions for preparation of phototoxic supersaturated solutions for antimicrobial photodynamic therapy (aPDT) Studies on curcumin and curcuminoides L -

Curcumin is under investigation as a potential photosensitizer (PS) in antimicrobial photodynamic therapy (aPDT). The therapeutic potential of curcumin as a PS is limited by its low aqueous solubility, susceptibility to hydrolytic and photolytic degradation, and limited phototoxicity toward Gram negative (G-) bacteria.

Solid dispersions for preparation of phototoxic supersaturated solutions for antimicrobial photodynamic therapy (aPDT): Studies on curcumin and curcuminoides L -

Curcumin is under investigation as a potential photosensitizer (PS) in antimicrobial photodynamic therapy (aPDT). The therapeutic potential of curcumin as a PS is limited by its low aqueous solubility, susceptibility to hydrolytic and photolytic degradation, and limited phototoxicity toward Gram negative (G−) bacteria.

Influence of different mould materials on the degree of conversion of dental composite resins -

In this study, the degree of conversion (DC) was analyzed on the surfaces of dental composite resins cured in different mould materials with different irradiation times.

Surface structure of fiber-reinforced composite implant and its effect on the attachment of implant to simulating bone material -

Fiber-reinforced composite (FRC) made of polymethyl methacrylate (PMMA) and E-glass fibers has been developed for bone segment defect reconstructions. It has been shown that exposed glass fibers predispose intergration of implant to bone. The aim of this study was to investigate how fibers of the implant surface can be exposed by solvent treatment and how the exposed fibers with different orientations effect the attachment of the implant to a bone simulating material

Import av tanntekniske arbeid -

I Europa reguleres alle dentalmaterialer av Direktivet for medisinsk utstyr. Tanntekniske produkter klassifiseres som «individuelt tilpasset utstyr», og slikt utstyr er unntatt CE-merking, men tannteknikeren skal bekrefte at arbeidet tilfredsstiller kravene i direktivet. Produktene skal fortrinnsvis fremstilles av CE-merkede materialer (1). Det er også krav om at materialene som blir brukt i importarbeider tilfredsstiller kravene i EU-direktivet, og det skal derfor følge med dokumentasjon på overensstemmelse med direktiv 93/42/EØF. Helsemyndighetene skal kunne gjennomføre markedskontroll for eksempel ved å se om arbeidenes faktiske og deklarerte sammensetning stemmer overens.

Titan – det biokompatible metallet med potensial for forbedring -

Over and above titaniums’s acknowledged biological and biochemical compatibility with the body, the biomechanical compatibility can be improved through alloying and heat treatment that reduce its inherent stiffness, bringing it closer to the stiffness of tooth structure, while increasing its strength.