Welcome to the overview of our newsletters!
We hope you will enjoy our newsletters. Your comments and questions are always welcome.
- Silanising agents promote composite repair
Repair of defective composites restorations instead of full replacement. Can silanising agents play a part to improve the strength of repair interface in combination with commonly used bonding products. Read more
- FTIR Spectroscopy for measurement of curing
Fourier Transform Infrared spectroscopy (FTIR) may be used to determine the degree of conversion. A well-documented method for restorative composites uses the peak of the aliphatic C=C double bonds at 1638 cm-1 of the unreacted methacrylate groups versus the stable peak of the aromatic C=C double bond at 1608 cm-1 found in the Bis-GMA monomer. Read more
- Strength of all-ceramic crown is influenced by the margin design
The study showed that by producing the crown core with a cervical collar of un-veneered zirconia, the strength increased without jeopardizing the aesthetics. Read more
Dental restorations are often combinations of two or more materials joint together with chemical or mechanical bonding. As well, they are often bonded to teeth. The bond strength between the different materials is crucial for the longevity of a restoration. Differences in material properties will affect the binding properties. Read more
- New monomer in dental composites
Summary of a Master thesis by Torbjørn Knarvang. Read more.
- NIOM TESTED: New product groups
NIOM’s program for the quality evaluation of dental products has been enlarged with three new product groups. Read more.
- Base-metal restorations seem safe
The aspect of patient safety was addressed in a research project with the aims to investigate the release of elements from, and the biological response in vitro to, cobalt-chromium alloys and other base-metal alloys used for the fabrication of metal-ceramic restorations. Read more.
- High sensitivity analytical instruments (GC/MS and LC/MS)
- Materials for indirect restorations.
When NIOM presented Norwegian Dental Association’s annual meeting and Swedental in 2015 the topic was “Materials for indirect restorations; both metals and all-ceramic materials”. Here you can read a brief summary of the presentations:
- The effect of polymer-based dental composites on living cells.
Knowledge of the mechanism by which monomers interact with living cells is of great value for risk evaluation. Read more.
- Is the caries risk reduced by placing a restoration.
Will the increased risk for caries development be eliminated when restoring the decayed surface with a restoration? NIOM scientist Dr. Kopperud has elucidated the question. Read more.
- Design and quality – ceramic crown strength. Read more.
- Easy-to-use, easy-to-regret over-the-counter bleaching products.
In 2011 all but one patient reported side effects of over-the-counter (OTC) bleaching products while their teeth became noticeably whiter. Read more.
- New expertise in organic synthesis at NIOM.
- Standards for digital dental impressions.
The International Organization for Standardization, ISO, published a revised version of ISO 12836, the standard for assessing the precision of the scanning devices used in dentistry to create digital impressions for prosthetics. Read more.
- Standardization. Read more.
- Restorative treatment of erosive lesions among norwegian dentists.
A survey showed that dentists were relatively up to date regarding clinical recording and diagnosis of dental erosive wear, although some inconsistencies were seen in treatment decisions.Read more.
- How to perform questionnaire studies. Read more.
- Chairside CAD/CAM – The dentist as quality manager
While many dentists send the digital impression to a dental technician with a purchase order for the required prosthesis, chairside manufacture offers the advantage of one-session treatment and the close involvement of the dentist in producing the prosthesis. Read more.
- Vacant positions as visiting scientist at NIOM during 2016. Read more.
- SCENIHR has published an opinion on the use of bisphenol A (BPA) in medical devices
SCENIHR adopted the temporary oral tolerable daily intake (t-TDI) of 4 μg/kg bodyweight/day derived by the European Food Safety Authority (EFSA). The SCENIHR opinion considered that BPA has low systemic bioavailability by the oral route. Read more.
- Mechanical properties
Mechanical properties describe a material’s response when exposed to various mechanical impacts such as tension, pressure or deflection or even temperature change. As such, they are crucial in evaluating the quality of a dental material or indeed any material. Read more.
- Chitosan – Antibacterial use in dental materials
Secondary caries is the primary reason for replacement of composite fillings, and clinical studies report more secondary caries when composites are used compared to amalgam in high-risk caries groups. This highlights the need for development of materials that will reduce or inhibit biofilm formation on dental materials. Read more.
- Techniques for studying biofilm. Read more.
- Overseas and Norwegian-made dental crowns – does the delivery meet the ordered specifications?
The compliance between ordered and delivered alloy composition content of toxic elements (Ni, Cd and Be), and stated declaration of conformity with the Medical Devices Directive were investigated. The investigation revealed major deficiencies for both imported and Norwegian-made crowns. The deviation in the composition was especially pronounced for the imported crowns. Read more.
- A new look at light curing in dentistry
Guidelines. Read more.
- Degree of cure of composite restorations
An important criteria for a long-lasting restoration of a polymer-based material, is a proper curing throughout the entire restoration. To achieve this, an effective polymerization is crucial so that the polymer network will extend throughout the material. This will ensure good mechanical properties and low amounts of residual monomers. Different methods exists that may monitor the curing or the polymerization of a polymer-based composite material for dental restorations. Read more.
- NIOM at NTF Landsmøte and Rikstämman.
Tooth-coloured restorations – choice of materials, procedures and longevity.
Read more …
- Antimicrobial photodynamic therapy: a new antibacterial treatment
As the rise in antibiotic resistant bacteria worldwide accelerates, there is a great need for alternative antibiotic treatments like antimicrobial photodynamic therapy (aPDT). Read more …
- Western blotting
Information on altered expression of toxicologically relevant genes is important when analyzing the underlying mechanism of toxic responses in cells. Western blotting is a common method to identify and quantify level-changes of proteins in tissues and cells exposed to possible toxic compounds. Read more …
- Improved composite repair
Repairing and extending composite restoration are common and well-accepted procedures for the dental practitioner. Evaluation of the repair strength has great research focus by using tensile and shear bond strength measurements. The present collaborative study from NIOM has assessed the effect of surface treatments and bonding systems on the repair bond strength between composite materials after one and 12 months of storage, using tensile test method. Read more …
- New research group at NIOM. Read more …
- Testing of all-ceramic crowns – from the laboratory bench to clinical relevance
Fractures during clinical function have been reported as one of the major causes for failure associated with all-ceramic dental restorations. 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.A new method for simulation of clinical fractures in ceramic crowns was recently presented (see Dental Materials 2013; 29:815–23). Read more …
- Seminar invitation. Read more …
- Integrated composites for hard tissue repair
In oral and orthopaedic surgery, composites can be used as implants or bone grafts. Their functions are to direct, supplement or replace living tissues. The greatest synergy of every constituent of the composite is to combine different material properties. In fact, the properties of functional composites can be customized to match those of the target tissues.
Read more …
The delightful combination of a coffee and an ice cream sets the parameters for one of the most used test protocols for dental materials. The international standard for testing dental adhesives stipulates an ageing procedure in which test specimens are held repeatedly first in 5 °C cold water and then in 55 °C hot water for a large number of cycles. The result of subsequent testing invariably shows degradation in adhesive strength. It is important that this loss of bonding is limited. Read more …
- Dental composites modulate cytokine signaling in cells
Oral diseases such as periodontitis and gingivitis are inflammatory processes induced by bacterial biofilms. The bacterial factor lipopolysaccharide (LPS) is an important virulence factor of gram-negative bacteria, and plays an essential role in triggering periodontal inflammation. Read more …
- Microbiology testing and research
The Colony Forming Unit (CFU) method can be used for identification of microorganisms and for testing the effect of antimicrobial substances and techniques. It is a sensitive and widely accepted method within microbiology. Read more …
- Appropriate dental materials for treating elderly, infirm, institutionalized patients
The deterioration in dental health that occurs when elderly people move into institutional care can be dramatic. Good, life-long habits of dental hygiene are broken, either because the move is associated with significant new health problems, or because daily routines have been upset. Read more …
- Dynamic mechanical testing
Because dynamic testing makes it feasible to estimate the expected lifetime of a restorative or prosthetic material, NIOM decided to add a dynamic test machine to our laboratory instrumentation. Read more …
- Glass-ionomer cements are also technique sensitive materials
A review of glass-ionomer materials points out that moisture control is mandatory for the longevity of the restoration.
Water contact at placement or at setting results in dissolution of the material. Read more …
- New method: Skin irritation test for evaluation of medical device extracts
EpidermTM is a 3D skin model derived from human epidermal keratinocytes which have been cultured to form a multilayered, highly differentiated model of the human epidermis. The model parallels human skin, and can provide a useful in vitro means to assess dermal irritancy and toxicology. Read more …
- Treatment decisions on approximal caries and longevity of Class II restorations; a PhD thesis
A newly published PhD thesis reveals significant changes in Norwegian dentists’ treatment decisions on approximal posterior caries during the last 26 years. Today, few dentists treat operatively lesions confined to enamel, and saucer-shaped preparations filled with resin composite is the most favoured approach to restore Class II lesions. In a clinical study, amalgam restorations perform better than resin composites, and failure of resin composites is among other things related to use of saucer-shaped preparation technique. Read more …
- LED lamp measurements
NIOM can offer spectral measurements of your curing lamps both for clinical and research use. Read more …
- Discomfort and pain are common after tooth bleaching
Up to 60% of the patients who underwent tooth bleaching reported one or more side effects within 14 days after treatment. For some patients, the pain was persisting for a year. Read more …
- Mixing of experimental composites
NIOM offers testing of experimental materials, prepared under controlled and repeatable mixing conditions. Read more …
- NIOM promotes patient safety in the Nordic countries Read more …
- NIOM at NTF Landsmøte and Rikstämman Read more …
- Explaining the toxicity of methacrylate monomers
Different methacrylate monomers, a major constituent of most polymer-based dental materials, are believed to hold similar toxic potential. An in vitro study comparing frequently used monomers, however, points out different cell responses to the different monomers. Read more …
- Flow cytometry
Flow cytometry is a technology that simultaneously measures and then analyzes multiple characteristics of single particles, usually cells, as they flow in a fluid stream through a beam of light.
Read more …
- Aging and strength of zirconia materials
Aging of zirconia (zirconium dioxide) based materials is associated with surface structural changes caused by humidity at elevated temperatures. Read more …
- HET-CAM test
HET-CAM test (hen’s egg-chorioallantoic membrane test) is a test used to determine the irritation potential of substances and is an alternative test to the Draize Rabbit Eye Test. In the test, incubated hen’s eggs are opened carefully on day 9 and the chorioallantoic membrane (CAM) is exposed. Read more …
- Leaching from endodontic materials
Laboratory investigations indicated that the cytotoxic potential of root canal sealers corresponded with the degree of leaching of methacrylate-based polymeric materials. Leached components from cured materials of this type caused cells of oral origin to die. The severity of cell death increased with the time of exposure in the cell culture.
Read more …
- Chemical analysis for the evaluation of biocompatibility
Evaluation of the biocompatibility of dental materials may be a complex task. Chemical analysis using in vitro investigations may be helpful to elucidate the biocompatibility of the materials through investigation and control of eluted substances. The aim of such investigations is to increase patient safety. Read more …
- Simulating clinical fractures of all-ceramic crowns
A laboratory method was developed to mimic the cervical fractures of all-ceramic crowns seen in the clinic. By this method, occlusal force was applied on crowns using abutment material with compression/expansion characteristics similar to dentine. In this way, different ceramic materials may be compared with regard to the fracture risk of all-ceramic crowns. Read more …
- The monomer HEMA may interfere with DNA in vitro
The cytotoxic monomer HEMA (2-hydroxyethyl methacrylate) is a common ingredient in resin-based dental restorative materials with the potential of diffusing into pulpal tissue or be released into the oral cavity. In vitro experiments using different biochemical methods indicate that the cytotoxic potential of HEMA in lung epithelial cells is mediated by DNA damage of non-oxidative origin.
Read more …
- Improving dentin bond strength
Collagenolytic enzymes such as matrix metalloproteinases in mineralized dentin may impair the bond between the resin restoration and the dentin. Current research focuses on the application of enzyme inhibitors to prevent the collagen degradation and improve the bond strength and durability. Read more …
- Monomers from composite fillings may impair the immune response of macrophages
Experimental evidence using a macrophage cell line indicates that methacrylate monomers inhibit the release of pro-inflammatory cytokines induced by lipopolysaccharide endotoxin from gram-negative bacteria present in dental biofilms. This effect may have negative implications for the macrophage immune response. Read more …