Verification of lateral flow antigen tests for SARS-CoV-2 by qPCR directly from the test device.

OBJECTIVE: Fast and reliable detection of infection is a key to control the SARS-CoV-2 pandemic. Lateral flow antigen tests (LFATs) are inexpensive, easy to use, but have to be verified, as they are rather unspecific and can produce both, false positive and false negative results. Our objective was to combine the speed of LFAT for SARS-CoV-2 with the reliability of qPCR tests. METHODS: A serial dilution of a patient sample positive for SARS-CoV-2 was prepared and added to LFAT wells from two manufacturers. After evaluation, the devices were opened, the strips removed and extracted in a solution. Amplification was performed using point of care PCR systems (cobas® Liat®, ID NOW™) or on a LightCycler after extraction by MagNAPure 96. RESULTS: The nucleic acid amplification systems yielded higher sensitivity to LFAT. Thus, all samples determined positive by LFAT from the serial dilution were also positive in the subsequent amplification reactions. Sensitivity using extracted eluates was 10-100 times higher. SIGNIFICANCE: The usage of LFAT is highly recommended for single samples in emergency dental or emergency clinical settings, for smaller cohorts, or even for larger population screening, as it is inexpensive and fast. Positive results can be conveniently verified directly from the test devices using either point of care test equipment or more complex laboratory equipment thus making a major impact on efficient management of infections and isolations.

Direct and indirect eluates from bulk fill resin-based-composites.

OBJECTIVES: To compare elutable substances directly released from bulk-fill (BF) resin-based composites (RBCs) with indirect elution from teeth restored with a BF composite. In addition to (co)monomers, the analytical focus was on other potentially toxic ingredients or impurities. Furthermore, the barrier function of the residual dentin/adhesive layer was studied. METHODS: Six BF-RBC materials were studied. For each material subgroup, ten human third molar teeth with standard Class-I occlusal cavities were prepared and provided with a three-step adhesive system and the respective composite restoration (tooth groups). Same sized control specimens of the restorative material were prepared ('direct BF-RBC' groups). Each specimen was placed in an elution chamber such that the elution media (ethanol/water, 3:1) only contacted the tooth root or ¾ height of each specimen. They were incubated at 37 °C for up to 7 d. Samples of eluate were taken after 1, 2, 4 and 7 d and were analysed by high-temperature gas chromatography/mass spectrometry. RESULTS: (Co)monomers such as Bisphenol A ethoxylate dimethacrylate (bisEMA) or tetraethylene glycol dimethacrylate (TEEGDMA) were mostly found in the eluates of the 'direct BF-RBC' groups in statistically significantly greater amounts than in the eluates of the 'tooth groups'. The residual dentin and/or adhesive layers acted as a diffusion barrier for most of the substances except for triethylene glycol dimethacrylate (TEGDMA) or diethylene glycol dimethacrylate (DEGDMA). For TEGDMA up to 3 orders of magnitude more were found in the 'tooth groups' compared to the 'direct BF-RBC' groups, evidently released by the adhesive system. Substances of Very High Concern (SVHC) including TINUVIN® 328 and BPA were found mainly in the eluates of 'direct BF-RBC' groups. SIGNIFICANCE: For estimation of biocompatibility, a total system, specifically BF-RBC + adhesive, should always be investigated since individual considerations, such as only elution from a BF-RBC, do not correctly reflect the total clinical situation. The focus of elution tests should not only be on the co(monomers), but also on other ingredients or impurities that may be released.

SARS-CoV-2 and regular patient treatment - from the use of rapid antigen testing up to treatment specific precaution measures.

INTRODUCTION: The COVID-19 pandemic poses a continued challenge for all parties involved especially for the dentist as routine operation must be resumed. Rapid Antigen Tests (RATs) are actually recommended to identify and minimize infectious risks. However, there is still no guideline on the implementation of RATs in a dental or medical setting. METHODS: Based on data and an extensive literature research regarding rapid antigen testing and reflecting the recommendations given by the various professional societies a task force was formed to determine a specific testing and treatment strategy. RESULTS: A comprehensive test and treatment strategy and risk analysis was developed with practical suggestions for a wide range of typical activities in dental and medical offices. The transmission of SARS-CoV-2 and its variants via aerosols and droplets as well as the difficulties to maintain the minimum distance form special challenges to the dental routine. RATs might in addition to optimal and necessary hygienic standards in combination with the use of adequate personal protection equipment be an important instrument in managing the challenges. CONCLUSIONS: The present work gives recommendations for dental routine operation (dental practices, outpatient clinics) to provide the necessary dental care for the population while protecting the doctor, practice team and patient at the same time.

Direct and indirect monomer elution from an RBC product family.

OBJECTIVE: To develop a model for quantitative comparison of elutable substances by direct elution from resin-bonded composite (RBC) test specimens versus indirect elutability of substances from RBC-restored teeth. Furthermore, it was to be investigated whether the different composites of the Tetric® RBC product family release different types and amounts of substances. METHODS: Four different composite materials from the Tetric® product family were studied. For each material subgroup ten human third molar teeth were prepared with standard Class-I occlusal cavities. These 'tooth group' specimens were provided with a three-step adhesive system (incorporating TEGDMA) and the respective composite restoration. Same sized control specimens, of each RBC restorative material, were prepared ('direct RBC' groups). All specimens were placed in individual elution chambers such that the elution media (ethanol/water, 3:1) only came into contact with either the tooth root or ¾ height of the 'direct RBC' materials. They were incubated at 37 °C for up to 7 d. Samples of the eluant were taken after 1, 2, 4 and 7 d and were analysed by high-temperature gas chromatography/mass spectrometry. RESULTS: Bisphenol A ethoxylate dimethacrylate (bisEMA), bisphenol A glycidyldimethacrylate (bisGMA), tetraethylene glycol dimethacrylate (TEEGDMA), decan-1,10-diol dimethacrylate (DDDMA) were mostly found in the eluates of the 'direct RBC' groups in statistically significantly greater amounts than in the eluates of the 'tooth groups'. Such quantitative differences were also the case with eluates containing bisphenol A (BPA), dicyclohexyl phthalate (DCHP) and drometrizole, which are common in the environment. In contrast to the behavior found with all the other monomers, up to 3 orders of magnitude more triethylene glycol dimethacrylate (TEGDMA) was found in the 'tooth groups' compared to the 'direct RBC' groups, evidently released by the adhesive system. SIGNIFICANCE: The release of most of the substances was clearly delayed in the 'tooth groups' indicative of their chronic, rather than acute, elution to the oral environment. A barrier function of the residual dentin layer and the adhesion layer can be inferred. The different release patterns of substances from the various composites of the RBC product family is a manifestation of their different and indication-specific compositions. Consideration of an overall restorative care (RBC plus adhesive) system, when assessing the total amount of released substances, is emphasized.

An alternate methodology for studying diffusion and elution kinetics of dimethacrylate monomers through dentinal tubules.

OBJECTIVE: Ethoxylated bisphenol A dimethacrylate (bisEMA) is a base monomer in several dental resin composites. It was the main aim of the present study to determine if bisEMA can reach the dental pulp by generally passive diffusion through the coronal dentinal tubules stimulated via eluent liquids surrounding the root structures only. METHODS: In 20 human third molar teeth, standard Class-I occlusal cavities were prepared and provided either with an adhesive system alone or additionally with a composite restoration, according to the instructions of the manufacturer. The teeth were placed in an elution chamber such that the elution media only came into contact with the tooth root/tooth base where they were incubated at 37 °C for up to 7 d. Samples were taken after 1, 2, 4 and 7 d. Gas chromatography/mass spectrometry was used to identify bisEMA and other monomers in ethanol/water (3:1) and aqueous eluates. RESULTS: bisEMA was only found in ethanol/water eluates, where the teeth had received a composite restoration. Traces of bisEMA with up to three ethylene oxide units could be detected in these eluates. Depending on the dentin thickness, different elution kinetics of bisEMA were determined. Regardless of the treatment of teeth, triethylene glycol dimethacrylate (TEGDMA) and tetraethylene glycol dimethacrylate (TEEGDMA) were found in ethanolic/aqueous eluates in equal amounts. Most TEGDMA and TEEGDMA diffused through the dentin within the first 24 h. SIGNIFICANCE: Depending on the dentin layer thickness, bisEMA was released for varied time periods, resulting in varied concentrations and exposure times for the different cells of the dental pulp. The concentrations of TEGDMA and TEEGDMA were greatest for cells of the dental pulp within the first 24 h.

Effectiveness of dentifrices with new formulations for the treatment of dentin hypersensitivity - A meta-analysis.

PURPOSE: This meta-analysis was conducted to evaluate if strontium-acetate- and arginine-containing dentifrices can significantly reduce dentin hypersensitivity (DH). METHODS: A systematic literature search was performed. The investigation period was from 2006 to 2015 with the search term "dentin hypersensitivity". Nine original articles were relevant. A network meta-analysis of combined z scores was performed. Pooled results from random effects models with their 95% confidence intervals are reported. RESULTS: The results from the random effects network meta-analysis show a significant improvement for the agents strontium acetate, arginine, and arginine with whitener, at all times for all stimuli, in comparison with the placebo. Strontium chloride is equivalent to the placebo. None of the dentifrices had a negative effect on DH. This meta-analysis showed that strontium-acetate- and arginine-containing dentifrices can significantly reduce DH. Calcium sodium silicate and potassium nitrate formulas show a tendency for pain relief. Because of the limited power of the available studies, a randomized study with several agents is recommended. CLINICAL SIGNIFICANCE: The aim of the treatment of dentin hypersensitivity (DH) is pain relief. Dentifrices with formulations of strontium acetate, of arginine or of arginine with whitener seem to have a good impact in the therapy of DH and can be recommended for daily use.

The prevalence of tooth hypersensitivity following periodontal therapy with special reference to root scaling. A systematic review of the literature.

PURPOSE: To provide a current status of the art, answering the question whether a certain procedure of periodontal treatment is more reliable than another and where innovative developments could improve on the incidence of hypersensitivity by a systematic literature review. METHODS: Pubmed, Embase and Cochrane library were considered for the study. 2,656 articles of the PubMed search were found, from the beginning of 1945 until April 2011. 99 articles from PubMed were evaluated for this review. From Embase, 60 articles were selected and one was included in this review. From the Cochrane library, 182 were found, of which two contributed to the review. Included were all studies dealing with periodontal treatment followed by hypersensitivity and all studies dealing with the loss of attachment, followed by hypersensitivity. Excluded were any treatments of tooth hypersensitivity with pathogenesis not related to dentin exposure, genetically caused disorders, and fractures. Ultimately, 102 papers were evaluated, included and referred to in the review. RESULTS: The term "tooth hypersensitivity" is most often used. Common causes of loss of hard substance are listed and updated. Mechanical loss of hard tissue formed one group of etiological factors; gingival recession and loss of attachment another. Surgical interventions, scaling and root planing were considered and in most cases performed as combined procedures. The different methods were evaluated and critically discussed. There were no properly randomized studies in the literature. The weak point of all epidemiological studies is the lack of any objective measurement. With respect to periodontal therapy, further research and developmental work on medical devices is needed, as well as ongoing applied research with laser technologies, continuing education and training programs for professionals.

ε-Caprolactone in micro-chambered ceramic beads--a new carrier for gentamicin.

PURPOSE: The purpose of this preliminary and descriptive study was to evaluate a biodegradable drug delivery system in combination with an innovative ceramic implant. METHODS: The delivery of gentamicin of standardized samples was measured in the laboratory using ultra-high-performance liquid chromatography. Biocompatibility and biodegradation of the materials was investigated in an animal experiment in sheep up to 14 months. As carrier ε-caprolactone, 1:1 mixed with gentamicin, intruded into micro-chambered ß-tricalcium-phosphate beads (MCB®) was studied. RESULTS AND DISCUSSION: Gentamicin was released in calculable concentrations during the first 30 days. The release from ε-caprolactone was higher than that from polymethylmethacrylate and more predictable. The caprolactone carrier was reabsorbed by osteoclasts.