Bo Wold Nilsen

A targeted ultrahigh-performance liquid chromatography–high-resolution mass spectrometry (UHPLC–HRMS) workflow was developed for the screening, identification, and semi-quantification of extractables and leachables from biomaterials with special focus on dental polymer-based composites. The method combined an in-house spectral library, a compound database, and a relative response factor database based on two surrogate standards to enable both qualitative identification and concentration estimation across a broad analyte set. The target list comprised 119 compounds relevant to resin-based materials, including methacrylate monomers, photoinitiators, additives, stabilizers, and hydrolysis products. The list also contained major per- and polyfluoroalkyl substances. Method validation for selected priority analytes in artificial saliva and DMEM demonstrated good selectivity, linearity, recovery, and precision, with low ng/mL detection and quantification limits for most compounds. The approach was applied to three representative scenarios: leachables from a 3D-printed dental splint, airborne chemicals in inhalable dust generated during orthodontic adhesive removal, and product control of unpolymerized dental composite resins. In the splint case, clinically relevant leachables including phenoxyethyl methacrylate and the photoinitiator TPO were detected, with markedly higher extractable amounts in acetone than in artificial saliva. Analysis of inhalable dust revealed particle-associated organic compounds originating from orthodontic adhesive materials, including BisGMA-related species and other resin constituents. Product control of commercial composites showed that declared ingredients were generally confirmed, but several undeclared compounds and composition differences were also observed. Overall, the workflow provided a robust and versatile platform for comprehensive targeted analysis of dental biomaterial-related chemicals and supports applications in exposure assessment, product verification, and clinical investigation.

Objective: This study aimed to investigate the following: (1) the preferences of public dentists for procedures and materials in carious or non-carious pulp exposure of permanent teeth; (2) how factors such as clinical experience, scientific literature reading, and material availability affect their choices; (3) the self-assessed risk of root canal treatment after pulp capping. Materials and methods: An online questionnaire consisting of 20 multiple choice and open-ended questions was e-mailed to Norwegian public dental clinics. It assessed dentists’ material preferences for direct pulp capping for carious or non-carious exposures, alongside factors such as years since graduation, scientific literature engagement, availability of materials, and clinical scenario choices. Respondents were also asked to estimate and reason long-term outcomes of their chosen materials. Standardized case descriptions ensured shared clinical understanding. Data were statistically analyzed and p-values ≤ 0.05 were considered statistically significant. Results: A total of 218 (23.9%) dentists responded. Direct pulp capping was preferred by 65% of respondents, with chemically curing materials – primarily calcium hydroxide – being most used. Chi-square analyses showed that dentists with fewer years of experience and those who had read scientific literature were more likely to prefer calcium silicate materials; however, these variables were not statistically significant predictors in the logistic regression models. Material availability was the strongest predictor of preference, with significantly increased odds of selecting calcium silicates or light-curing materials when available. ‘Satisfied with clinical results for the chosen material’ was the most frequently reported reason for material selection. Conclusion: Most respondents in this study preferred calcium hydroxide for direct pulp capping in permanent teeth with closed apices, despite the superior clinical outcomes of hydraulic calcium silicates. Material availability in the clinic was the primary factor influencing dentists’ choices, surpassing clinical experience and scientific literature engagement.

English summary: Price tariffs in orthodontics: differences between public, private, and Helfos rates: Nor Tannlegeforen Tid. 2024; 134: 1032-8. Background/Purpose: About half of Norwegian children receive orthodontic treatment, yet socioeconomic disparities exist due to partial government funding. This study aimed to explore economic barriers to orthodontic care by examining differences in rates between Helfo and private/public orthodontists, and assessing the actual percentage of financial support given by HELFO to patient in need of orthodontic treatment. Method: A questionnaire was sent to Norwegian orthodontists through the Norwegian Orthodontic Association to survey tariffs and additional out-of-pocket expenses. Differences in pricing between private and public orthodontists for individual fees and a hypothetical treatment course were examined. Due to a low response rate from public orthodontists, fee information was directly obtained from all county councils. Results: There were 32 respondents (29 private, 3 public), with a total of 22 public and 14 private orthodontists included in the fee analysis. Significant price differences were noted on specific tariffs, but not across a hypothetical treatment scenario. Both private and public orthodontists generally charge more than Helfo’s rates, leading to higher patient out-of-pocket expenses. Actual Helfo reimbursements for patients were approximately 70 %, 50 %, and 30 % for group a, b and c. Conclusion: The study found that both private and public orthodontic fees significantly exceed Helfo’s, increasing out-of-pocket costs for patients and reinforcing financial barriers to orthodontic care in Norway.

English summary: How do dental health professionals chart and understand the concept of “major difficulties with mental and social coping” related to malocclusions?: Nor Tannlegeforen Tid. 2022; 132: 1016-26. In 2020, a subjective assessment was introduced in the reimbursement system for orthodontic treatment in Norway. The aim of the study was to investigate how dental health personnel chart and understand the term “major difficulties with with psychological and social coping” in relation to malocclusions, as well as to investigate what they think of the changes to the reimbursement system. The study used a “mixed method” approach (focus groups and questionnaires). Digital questionnaires were distributed to dentists, dental hygienists, and orthodontists employed in the public dental health service, as well as private practicing orthodontists. The response rate was approximately 20% for dentists and dental hygienists, and 30% for orthodontists. Dental health personnel emphasize different factors when mapping difficulties with psychological and social coping in relation to malocclusions. Bullying and smile aversion were the two most important factors that were emphasized. Approximately 10% of the dental health professionals were satisfied with the guidelines on how to assess whether the patient has difficulties with psychological and social coping linked to malocclusions. More than 70% of the orthodontists were dissatisfied with the guidelines. Less than 1/4 of the orthodontists stated that they understand the concept, or feel competent to evaluate, psychological and social coping. The figures were somewhat higher for referring dental health personnel. Varying interpretation of the concept psychological and social coping may imply that young people with malocclusions in group C (with 40% reimbursement) do not receive an equal offer of referral and orthodontic treatment with reimbursement.

Background: Light-curing of materials during restorative dental procedures poses a risk for pulp tissue overheating. Therefore, the aim of this study was to investigate the effect of indirect air-cooling on pulp chamber temperatures during light-curing of varying volume teeth and absence/presence of resin-based composite (RBC) at different exposure time. Methods: The volume of 11 human teeth was measured by micro computed tomograph. An experimental rig controlled the thermal environment of the teeth and a thermocouple inserted retrograde into the root canal measured temperature changes. Pulp chamber temperature was measured with and without air-cooling on teeth without and with RBC at 15 s, 30 s and 60 s intervals. Generalized estimating equations were used for statistical analysis. Results: The temperature increase with air-cooling (versus no air-cooling) was lower in teeth despite absence/presence of RBC (β = − 4.26, 95%CI − 5.33 and β = − 4.47, 95%CI − 5.60, respectively). With air-cooling, the temperature increase in teeth with RBC was lower compared to teeth without RBC (β = − 0.42, 95%CI -0.79; − 0.05). Higher teeth volume resulted in lower temperature increase with air-cooling than without air-cooling (β = − 0.04, 95%CI -0.07; − 0.01 and β = − 0.17, 95%CI -0.30; − 0.05, respectively). Conclusions: Air-cooling resulted in lower pulp chamber temperature increase. Using air-cooling, the temperature increase was lower in teeth with RBC compared to teeth without RBC. Lower volume teeth resulted in higher temperature increase, thus they seemed to benefit more from air-cooling compared to higher volume teeth. Air-cooling could be an effective tool in controlling pulp temperature increase during light-curing, especially when the tooth volume is small.

Objective: To assess whether composite polymer resin delivered in compules include pores and the possible effect on the amount of porosity in dental restorations. Method and materials: Original compules containing unpolymerised composite polymer resin (CPR) were scanned in a micro-CT. Four products were examined, which comprised universal composites (Herculite XRV Ultra, Ceram.X Universal, Tetric Evo Ceram) and a flowable bulk-fill composite (SDR) (n = 10 per group). The pore size distribution and amount of porosity (vol.%) were estimated for the unpolymerized and polymerized material used to restore a standardised cavity in a typodont tooth. Manufacturers’ instructions were followed regarding material handling, and polymerisation by use of a calibrated light-curing unit. The pore characteristics and their size distribution, and the amount of porosity in the dental restoration were contrasted with the values measured in the compule. Non-parametric tests were used to analyse differences between the four products. Results: All the composite polymer resin compules contained unpolymerised material that included pores. The universal composite compules included pores predominantly in the sub-100 µm sizes. In contrast, the flowable bulk-fill compules included a few pores with a diameter >100 µm, which were assumed to be air-bubbles. The unpolymerised material within the compule included consistently more pores compared to the extruded portion from the compule tip, and in the final restoration (p < .001). The amount of porosity in the restorations differed amongst the tested materials, with the flowable bulk-fill composite showing the lowest amount of porosity (p < .01).

Den norske tannlegeforenings Tidende – Noen betraktninger rundt bruken av lysherdende materialer for pulpaoverkapping - er raskere alltid bedre?

Dental composite dust has been shown to act as a vehicle for methacrylates in vivo/in vitro. The objective of this study was to assess airborne exposure of dental personnel to gaseous and particle‐associated organic constituents from resin‐based dental materials in a simulated clinic. Sampling of total aerosol fractions and gaseous substances was performed by dental students carrying particle filters and gas sorbents attached to a personal pump during preclinical restorative procedures in phantom models (n = 13). Water from the phantoms was sampled. Organic substances were extracted from the sampled water, particle filters, and gas sorbents. Qualitative and quantitative analyses were performed by gas chromatography‐mass spectrometry (GC‐MS) and ultra‐high‐performance liquid chromatography‐mass spectrometry (UHPLC‐MS). The methacrylates 2‐hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) and the additives camphorquinone (CQ), butylated hydroxytoluene (BHT), and ethyl 4‐(dimethylamino)benzoate (DMABEE), were quantified in the gas and particle fractions sampled. A positive‐control experiment was conducted. No methacrylates were detected in the gas or particle fractions sampled, whereas strong signals for methacrylates were detected in the positive controls, matching the analysis of the uncured material. In addition, TEGDMA and DMABEE were quantified in the sampled water. Airborne exposure to constituents in resin‐based dental materials was below the detection limit. However, the extent of exposure is probably dependent on the procedure, preventive measures, and type of materials used.

Triethylene glycol dimethacrylate (TEGDMA) is commonly used in polymer resin‐based dental materials. This study investigated the molecular mechanisms of TEGDMA toxicity by identifying its time‐ and dose‐dependent effects on the proteome of human THP‐1 monocytes. The effects of different concentrations (0.07–5 mM) and exposure times (0–72 h) of TEGDMA on cell viability, proliferation, and morphology were determined using a real‐time viability assay, automated cell counting, and electron microscopy, and laid the fundament for choice of exposure scenarios in the proteomic experiments. Solvents were not used, as TEGDMA is soluble in cell culture medium (determined by photon correlation spectroscopy). Cells were metabolically labeled [using the stable isotope labeled amino acids in cell culture (SILAC) strategy], and exposed to 0, 0.3 or 2.5 mM TEGDMA for 6 or 16 h before liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) analyses. Regulated proteins were analyzed in the STRING database. Cells exposed to 0.3 mM TEGDMA showed increased viability and time‐dependent upregulation of proteins associated with stress/oxidative stress, autophagy, and cytoprotective functions. Cells exposed to 2.5 mM TEGDMA showed diminished viability and a protein expression profile associated with oxidative stress, DNA damage, mitochondrial dysfunction, and cell cycle inhibition. Altered expression of immune genes was observed in both groups. The study provides novel knowledge about TEGDMA toxicity at the proteomic level. Of note, even low doses of TEGDMA induced a substantial cellular response.

The purpose of this study was to elucidate the organic composition and eluates of three resin‐based pulp‐capping materials in relation to their indications and safety data sheets. Uncured samples of Theracal LC, Ultra‐Blend Plus, and Calcimol LC were investigated using gas chromatography–mass spectrometry (GC‐MS) and ultra‐performance liquid chromatography–mass spectrometry (UPLC‐MS). Identification/quantification of 7‐d leachables of cured samples was performed using GC‐MS for 2‐hydroxyethyl methacrylate (HEMA), 2‐(dimethylamino)ethyl methacrylate (DMAEMA), camphorquinone (CQ), ethylene glycol dimethacrylate (EGDMA), ethyl‐4‐(dimethylamino)benzoate (DMABEE), and triethylene glycol dimethacrylate (TEGDMA). A similar organic composition was found for Ultra‐Blend and Calcimol; however, only Ultra‐Blend is indicated for direct pulp‐capping. In contrast to the other materials analysed, Theracal contained substances of high molecular weight. The safety data sheets of all materials were incomplete. We detected HEMA, CQ, and TEGDMA in eluates from Ultra‐Blend and Calcimol, and it was considered that HEMA might have originated from decomposition of diurethane dimethacrylate (UDMA) in the GC‐injector. For Theracal, additives associated with light curing (DMABEE and CQ) were detected in higher amounts (4.11 and 19.95 μg mm⁻²) than in the other materials. Pores were quantified in all samples by micro‐computed tomography (micro‐CT) analysis, which could influence leaching. The organic substances in the investigated materials might affect their clinical suitability as capping agents, especially for direct capping procedures.