The dental monomer HEMA causes proteome changes in human THP‐1 monocytes -

Resin-based biomaterials are widely used in medical and dental treatment, and both clinicians and patients are exposed to the materials.
The present approach to analyzing the toxic potential of HEMA yielded information on interactions with living cells is not previously reported. This detailed information is of great value to make better predictions of possible side effects in the clinic.

Hvor god er du til å bestemme farge på restaureringene dine? -

Uttak av farge til fyllinger, kroner, broer og proteser av alle slag, er ofte en frustrerende øvelse. Men fortvil ikke, det ser ut til at de som praktiserer fargeuttak ofte og øver jevnlig, blir gode, uansett alder. Øvelse gjør mester

Peroxide-free tooth whitening products -

The purpose of this study was to compare the bleaching effects of peroxide-free and peroxide-containing tooth whitening products.
After 8 months, no perceivable lightening was noted for the peroxide-free products whereas the teeth treated with peroxide containing bleaching remained lightened.

Effect of methacrylated chitosan incorporated in experimental composite and adhesive on mechanical properties and biofilm formation. -

The results of this study show that methacrylated chitosan (CH-MA) may be incorporated into a composite and into an adhesive to reduce biofilm formation on their surfaces. The mechanical properties of the composite were challenged, but flexural strength measurements still met the requirement set in ISO 4049, whereas no differences were observed for the bonding properties of the adhesives.

The dental monomer 2-hydroxyethyl methacrylate (HEMA) causes transcriptionally regulated adaptation partially initiated by electrophilic stress -

The airways of dental personnel can be exposed to low concentrations of HEMA on a daily basis. Thus, we aimed to explore altered gene expression in a bronchial epithelial cell line after exposure to “non-lethal” concentrations of HEMA, demonstrated to be 2 mM or below in the current model system. We show that the expression of a number of genes was altered in HEMA exposed cells.

Opinions and Treatment Decisions for Dental Erosive Wear: A Questionnaire Survey among Icelandic Dentists -

Interest in dental erosive wear is increasing, and new recommendations of less invasive approaches to the treatment of the condition are emphasized. Therefore, the main objective of the present study was to identify dentists’ knowledge, beliefs, and clinical behaviour toward the condition. The present study is the first of its nature to analyze and permit comparison of the knowledge and treatment decisions of dental erosive wear between different countries, as it is conducted in a similar manner as the recent questionnaire study from Norway. The importance of making such intercountry assessments is high.

Bonding of Composite and Glass-ionomer to Amalgam -

Amalgam restorations of adequate standard and condition can very well be repaired with composite, but there should be provided for extra retention into the amalgam filling as the bond strength alone is not adequate. Glass-Ionomer may also be used for repair at amalgam restoration margins in not stress bearing areas, but as they do not adhere to amalgam, they need enamel and dentine for retention and possible undercuts towards amalgam interface.

Di-n-butyl phthalate modifies PMA-induced macrophage differentiation of THP-1 monocytes via PPARγ. -

The present study was part of the research project Inhalation and prenatal exposure to phthalates: influence on airway immunology, conducted at the Norwegian Institute of Public Health, and was funded by the Norwegian research council (Research grant number: 228129).

Digital evaluation of marginal and internal fit of single-crown fixed dental prostheses -

The adaptation of single-crown fixed dental prostheses (FDPs) is a subject of great interest in the research community. Many investigations have been published, and a variety of evaluation methods have been used to determine the fit accuracy of prosthetics.
Many of the methods required manual measurements of the gap between the restoration and the abutment. With the introduction of CAD/CAM techniques, digital tools started being used for evaluating the adaptation of FDPs.
In this study, a tabletop dental scanner was used. It is anticipated that in a clinical setting, an intraoral scanner is sufficient, at least for single-crown FDPs.

Biofilms and their properties -

Oral biofilm‐associated diseases, such as caries and periodontitis, represent global public health challenges. The diseases develop as a result of dysbiosis of the oral microbiome. There is a long tradition in medicine for treating bacterial infections by the use of antibiotics. Unfortunately, biofilm bacteria are significantly less sensitive to antibacterial agents than are their planktonic counterparts. This property of biofilm challenges us in our daily work as dentists, and might explain why many oral prophylactic agents predicted to be efficacious in vitro, only show marginal effect in vivo.

New animal model of extrinsic dental erosion-Erosive effect on the mouse molar teeth -

Human experiments on dental erosion are unethical because of the irreversible loss of dental hard tissues when exposed to acids. Therefore, studies using animal models are of high importance since they represent clinical situations. Based on the present results it can beconcluded that cola drink (phosphoric acid, pH=2.27) exhibited higher erosive effect on mouse mandibular molars compared to sports drink (citric acid, pH=3.39). This new animal model of extrinsic dental erosion where lesions of different severity can be created is suitable for further studies that will improve our understanding of the disease. The present method with transversely ground molars observed in SEM allows a registration of erosive lesions and lesion depths in small teeth like mouse molars. Both studies on the salivary influence (e.g. by using knockout mice) and the studies on the effect of fluoride on development of erosive lesions are warranted.

Optimizing quality and safety of dental materials -

Optimizing quality and safety of resin‐based materials need coherent strategies. Proper handling and polymerization increase the rate of conversion and thus minimize the content of residual monomers. Measures to reduce biofilm accumulation at the tooth‐restoration interface could prevent or reduce the most common reason for restoration failure, recurrent caries.

Preparation and characterization of Bis-GMA-free dental composites with dimethacrylate monomer derived from 9,9-Bis[4-(2-hydroxyethoxy)phenyl]fluorene. -

New dimethacrylate monomer Bis-EFMA was synthesized and used to prepare Bis-GMA-free dental resin and composite materials. Studies of the experimental materials showed that Bis-EFMA-based resin matrix and composite materials had improved properties compared to Bis-GMA-based resin matrix and composite materials, respectively. Compared with the commercial dental composite material Z250, Bis-EFMA-based composite showed similar or improved properties except for a lower FS after water immersion. Based on the presented results, Bis-EFMA has potential to be used in commercial dental composites.

Presence and leaching of bisphenol a (BPA) from dental materials -

BPA has been reported to leach from some resin-based dental restorative materials and materials used for orthodontic treatment. To confirm and update previous findings, especially in light of the new temporary lower threshold value for tolerable daily BPA intake, leaching of BPA from 4 composite filling materials, 3 sealants and 2 orthodontic bonding materials were investigated.

Nrf2 Signaling and Cytoprotection in Human Epithelial Airway Cells Exposed to HEMA -

Methacrylates are common constituents of resin-based biomaterials. These materials cure by polymerization of methacrylate monomers, but incomplete polymerization causes leakage and patient exposure to the electrophile monomers.

Lysherding – så enkelt og så vanskelig. -

For kort herdetid kan føre til mangelfull herding (polymerisasjon) av komposittmaterialer. For lang herdetid kan øke risiko for varmeskade på oralt bløtvev og pulpa. Herdelampens lysstyrke (irradians) reduseres når avstanden øker mellom lysutgangen og materialflaten.
For å opprettholde lysdosen som kreves for tilstrekkelig herding, må herdetiden økes. Kortere lysherdingstider enn omtrent 10 sekunder kan føre til utilstrekkelig herding av materialet.

Side effects of chemical compounds used in dental clinics -

The work at a dental clinic implies getting in contact with different chemical substances, which may cause temporary or permanent injury to the staff, primarily allergic reactions, but also local irritation, carcinogenic or toxic effects. Dentists and dental assistants belong to the professional groups most frequently experiencing work-related eczema.

Redefining the Phenotype of Dental Caries -

To our knowledge, this is the first study to separate patients into more discrete groups based on dental caries experience defined from longitudinal data and the first to study acute increases in DMFT score between two time points. Our hope with doing so is to provide more power in our predictions of genetic influences of dental caries and perhaps lead to better ways of studying the disease based on more specific categorizations of phenotypes.

A retrospective clinical study on the longevity of posterior Class II cast gold inlays/onlays. -

All dental restorations have a limited lifespan and will eventually need to be repaired or replaced. It is important to have in mind that the longevity of gold restorations have not been shown to be superior to that of resin composite, which should still be the first material of choice. However, gold inlays could be considered when the right indications are present.

Taste and smell perception in aging (Aldring, smak og lukt) -

Taste and smell are senses reacting upon solutes from food and breathing air conveyed by the cranial nerves. Normal aging includes cellulary and extracellulary biochemical mechanisms detrimental to neurons in the central nervous system, including those processing taste and smell signals. Aging also means reduction of the number of taste buds in the oral cavity and of the number of odor receptors in the nasal mucosa.

Antibacterial Activity of Endodontic Sealers against Planktonic Bacteria and Bacteria in Biofilms. -

Antibacterial activity of 4 endodontic sealers against bacteria planktonic grown or in biofilms commonly detected from persistent and secondary endodontic infections.
Investigating the antibacterial activity of endodontic sealers and materials against bacteria in biofilms is highly important to evaluate the materials’ ability to eradicate bacteria from the infected root canal

Survival of extensive restorations in primary molars: 15-year practice-based study. -

Caries decline in the western world is accompanied by strong polarization among children; 8% of Finnish 5-year-olds having 76% of untreated caries. This high caries risk group needs preventive and restorative strategies.
Severely affected primary molars of children at high caries risk are better managed, using PMCs to optimize the resources in public oral health services.

Role of Proteolytic Enzyme Inhibitors on Carious and Eroded Dentin Associated With a Universal Bonding System -

Abstract Objectives: The aim of this study was to evaluate the effect of proteolytic inhibitors on the bond strength of a universal adhesive system (etch-and-rinse mode) applied to artificial carious and eroded dentin. Methods: Ninety molars were prepared and randomly divided into three groups according to the substrate: N, no challenges; ACD, artificial carious dentin […]

Internal fit of three-unit fixed dental prostheses produced by computeraided design/computer-aided manufacturing and the lost-wax metal casting technique assessed using the triple-scan protocol -

Suboptimal adaptation of fixed dental prostheses (FDPs) can lead to technical and biological complications. It is unclear if the computer-aided design/computer-aided manufacturing (CAD/CAM) technique improves adaptation of FDPs compared with FDPs made using the lost-wax and metal casting technique.

Komposittmaterialer – utlekking av monomer og cytotoksisitet -

NIOM har på oppdrag fra Helsedirektoratet undersøkt fire komposittmaterialer: ett Own Brand Label (OBL)-materiale, to bulk-fill materialer og et mye benyttet universalmateriale. Det ble funnet ubetydelige forskjeller i utlekket monomer mellom produktene. I en cytotoksisitets-screening med ekstrakter fra produktene var det noe forskjell mellom materialene. Ytterligere molekylærbiologiske undersøkelser viste imidlertid ingen indikasjon på celleskade. Basert på disse undersøkelsene kan ingen av produktene bedømmes som mindre sikre enn de andre.

Kontrol og bekæmpelse af dental biofilm -

Control and eradication of dental biofilm. This article gives a brief overview of antimicrobial compounds used for biofilm control and new technologies and strategies to combat dental biofilms.

SCHEER: Preliminary Opinion on the potential risks to human health of Light Emitting Diodes (LEDs) -

The Scientific Committee on Health, Environmental and Emerging Risks of the European Commission released the Preliminary Opinion in July. The Opinion was open for comments until September. NIOM scientist, Ellen Bruzell, served as external expert in the preparation of the Preliminary Opinion.

Is dental erosive wear a common condition among 16-year-olds in Troms, Norway? -

The aim of the present study was to investigate the prevalence, distribution and severity of dental erosive wear among 16-year old adolescents living in Troms. Clinical, intra-oral pictures of 392 individuals involved in the «Tromsø undersøkelsen, Fit Futures» were evaluated for dental erosive wear by three previously calibrated examiners.

Effect of curing and silanizing on composite repair bond strength using an improved micro-tensile test method -

To evaluate the micro-tensile repair bond strength between aged and new composite, using silane and adhesives that were cured or left uncured when new composite was placed.

Water sorption and solubility of polyamide denture base materials -

Some patients experience adverse reactions to poly(methyl methacrylate)-based (PMMA) dentures. Polyamide (PA) as an alternative to PMMA has, however, not been well documented with regard to water sorption and water solubility. The aim of this in vitro study was to measure water sorption and water solubility of two PA materials compared with PMMA, and to evaluate the major components released from the PA materials and the effect on hardness of the materials.

Kemiske stoffers skadevirkninger på tandklinikker (Side effects of chemical compounds used in dental clinics) -

The work at a dental clinic implies getting in contact with different chemical substances, which may cause temporary or permanent injury to the staff, primarily allergic reactions, but also local irritation, carcinogenic or toxic effects. Dentists and dental assistants belong to the professional groups most frequently experiencing work-related eczema. The chemical substances may originate from dental materials, such as mercury from amalgam and monomers from resin based materials. The substances may be released during preparation, polishing and removal of restorations. In addition, different biocides/chemical disinfectants are used for both clinical an infection control purposes. (Article in Danish)

Brug af fysiske værnemidler på tandklinikker (Use of physical protective equipment at dental clinics) -

Members of the dental team are exposed daily to biological, chemical and physical agents. These vary for example, from microorganisms to noise, and are present in forms as diverse as aerosols and gasses. National and international directives, legislation and guidelines for infection control, and occupational health issues intended for the dental clinic, govern the physical and other types of protection required. In addition, it is important to be acquainted with the justification for any specific protective item, when and when not to use it and when an upgrade is required. (Article in Danish)

Bacterial biofilm elimination using gold nanorod localised surface plasmon resonance generated heat -

Bacterial biofilm elimination using gold nanorod localised surface plasmon resonance generated heat.
A technique for antibiotic replacement using heat for biofilm elimination is proposed.
Gold nanorods exhibit localised surface plasmon resonance upon optical irradiation and when relaxing, absorbed energy is dissipated as heat, which is utilized to kill bacteria.
After 5 minutes of near infrared irradiation an average of 71% of early biofilms were eliminated.

Investigation of the antimicrobial effect of natural deep eutectic solvents (NADES) as solvents in antimicrobial photodynamic therapy -

Abstract Natural deep eutectic solvents (NADES) are a third class of liquids, separate from water and lipids. Some NADES, especially those containing organic acids, have been suggested to possess antimicrobial properties. Such properties may be advantageous when NADES are used as solvents in e.g. antimicrobial photodynamic therapy. However, to control the toxicity of acid-containing NADES, […]

A novel etching technique for surface treatment of zirconia ceramics to improve adhesion of resin-based luting cements -

Bonding of zirconia crowns and bridges to abutments is important, not only bonding of the thin resin layer to the abutment, but also bonding to the zirconia ceramic is crucial. Both mechanical and chemical adhesion are desired. Mechanical retention of dental porcelain achieved by etching with moderately concentrated hydrofluoric acid is not possible with zirconia ceramics. The purpose of this study was to show that etching is possible with relative low melting fluoride compounds such as ammonium hydrogen difluoride and potassium hydrogen difluoride.

Relation between In Vitro Toxicity and the Thiol-Reactivity of Methacrylates in Resin-Based Biomaterials -

In this study we aimed to further map the suggested relation between GSH-depletion and methacrylate toxicity by comparing the molecular effects of methacrylate exposure and GSH-depletion by inhibiting GSH-synthesis.

Leakage of Bisphenol A from Dental Materials -

We are daily exposed to a variety of chemicals. One example is the chemical Bisphenol A (BPA). Animal studies indicate that BPA has effects on liver, kidney and breast tissue. Possible endocrine disruption effects contribute to uncertainty around BPA.

The dental monomer hydroxyethyl methacrylate (HEMA) counteracts lipopolysaccharide-induced IL-1β release-Possible role of glutathione. -

HEMA reduced GSH levels and decreased IL-1β release from LPS-stimulated macrophages. The role of GSH in the regulation of IL-1β release was explored. GSH depletion alone could not explain the attenuation of LPS-induced IL-1β release. Electrophile reactivity toward other cellular molecules is a new working hypothesis

Light curing procedures – performance, knowledge level and safety awareness among dentists -

The study aimed to investigate dentists’ exposure to curing light and to obtain information about the dentists’ knowledge on practical use and technical features of their curing lights as well as their safety awareness.

Oral mikroflora – et reservoir av antibiotikaresistensgener? -

One of the most significant medical achievements in human medicine during the 20th century was the discovery and introduction of antibiotics. However, a short time after the introduction of new antibiotic compounds, resistant bacteria were discovered.