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Gallorini M, Krifka S, Widbiller M, Schröder A, Brochhausen C, Cataldi A, Hiller KA, Buchalla W, Schweikl H. Distinguished properties of cells isolated from the dentin-pulp interface. Ann Anat 2020; 234:151628. [PMID: 33212174 DOI: 10.1016/j.aanat.2020.151628] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/28/2020] [Accepted: 10/16/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Dental odontoblasts produce dentin mineralized matrix, trigger immune responses and act as sensory cells. The understanding of the mechanisms of these functions has been particularly restricted due to the lack of odontoblasts being cultivable in vitro. Because of the lack of specific markers to identify cells of the odontoblastic lineage, properties of the cells isolated from the dentin-pulp interface were compared to dental pulp cells, periodontal ligament cells, osteoblasts, skin fibroblasts, epithelial cells (A549) and HeLa in the present study. METHODS After surgical procedures, the pulp tissue was removed from the tooth crown, and cells were scrapped off the dentin-pulp interface. Explants from teeth of three patients were routinely cultivated, and cells were harvested after several weeks. Cell morphology and ultrastructure was studied by light microscopy (LM), scanning (SEM) or transmission electron microscopy (TEM). Expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), TRPV4, and S100 calcium binding protein A4 (S100A4) were analyzed at the protein level by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting using specific antibodies. The differential expression of S100A4 in the various cell lines was further investigated at the gene level by semiquantitative real-time PCR. Mineralization in the various cell types was observed after alizarin red staining after a 28 days incubation period. The immunophenotype of the cells was examined by flow cytometry using monoclonal anti-human antibodies CD90-FITC, CD73-PE, CD105-PE, CD29-PE, CD140a-FITC, CD144-PE, CD45-FITC or CD34-FITC. Differences between median values were statistically analyzed (Mann-Whitney U-test). RESULTS Cells from the dentin-pulp interface retain the polarity of odontoblast morphology in culture with an elongated, rounded cell body, and an extended cellular process. Ultrastructural analysis of the cells indicates high secretory activity including the extracellular deposition of fibrillar collagen. An extended rough endoplasmic reticulum is lined by a large number of ribosomes, and a vast number of secretory granules merges with the cell membrane. Protein expression of DSPP, DMP1, and TRPV4 as a transient receptor potential cation was detected in all cell lines. S100A4 was found differentially expressed in cultures of cells from tooth tissues. High expression of S100A4 was observed at the protein and gene level in two fractions of cells isolated from the dentin-pulp interface, but was absent or only weakly expressed in pulp cells. S100A4 expression in cells from the dentin-pulp interface and pulp cells is consistent with the intensity of the formation of mineralized nodules detected by alizarin red staining. Immunophenotyping revealed that a high percentage of CD73 (ecto-5-nucleotidase), an enzyme active on the surface of immune-competent cells, was expressed in cells of the dentin-pulp interface. While 72%-78% of positive cells were detected in dentin-pulp interface fractions, only 28-64% of the cells in pulp cell cultures were stained. CONCLUSIONS The present findings obtained with a variety of cells of different origin provide experimental evidence that cells isolated from the dentin-pulp interface express unique properties different from dental pulp cells in particular. The differential expression of S100A4 is a relevant marker candidate for differentiating between dental pulp cells and cells of the odontoblast lineage.
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Affiliation(s)
- Marialucia Gallorini
- Department of Pharmacy, University "G. d'Annunzio" Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, University Hospital Regensburg, D-93042 Regensburg, Germany
| | - Matthias Widbiller
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, D-93042 Regensburg, Germany
| | - Agnes Schröder
- Department of Orthodontics, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, D-93042 Regensburg, Germany
| | - Christoph Brochhausen
- Institute of Pathology, University of Regensburg, Franz-Josef-Strauss Allee 11, D-93042 Regensburg, Germany
| | - Amelia Cataldi
- Department of Pharmacy, University "G. d'Annunzio" Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
| | - Karl-Anton Hiller
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, D-93042 Regensburg, Germany
| | - Wolfgang Buchalla
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, D-93042 Regensburg, Germany
| | - Helmut Schweikl
- Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, D-93042 Regensburg, Germany.
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Rosentritt M, Schumann F, Krifka S, Preis V. Influence of zirconia and lithium disilicate tooth- or implant-supported crowns on wear of antagonistic and adjacent teeth. J Adv Prosthodont 2020; 12:1-8. [PMID: 32128080 PMCID: PMC7040450 DOI: 10.4047/jap.2020.12.1.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the influence of crown material (lithium-disilicate, 3Y-TZP zirconia) and abutment type (rigid implant, resin tooth with artificial periodontium) on wear performance of their antagonist teeth and adjacent teeth. MATERIALS AND METHODS A mandibular left first molar (#36) with adjacent human teeth (mandibular left second premolar: #35, mandibular left second molar: #37) and antagonistic human teeth (maxillary left second premolar: #25, maxillary left first molar: #26, maxillary left second molar: #27) was prepared simulating a section of the jaw. Samples were made with extracted human molars (Reference), crowned implants (Implant), or crowned resin tooth analogues (Tooth). Crowns (tooth #36; n = 16/material) were milled from lithium-disilicate (Li, IPS e.max CAD) or 3Y-TZP zirconia (Zr, IPS e.max ZirCAD, both Ivoclar Vivadent). Thermal cycling and mechanical loading (TCML) in the chewing simulator were applied simulating 15 years of clinical service. Wear traces were analyzed (frequency [n], depth [µm]) and evaluated using scanning electron pictures. Wear results were compared by one-way-ANOVA and post-hoc-Bonferroni (α = 0.05). RESULTS After TCML, no visible wear traces were found on Zr. Li showed more wear traces (n = 30–31) than the reference (n = 21). Antagonistic teeth #26 showed more wear traces in contact to both ceramics (n = 27–29) than to the reference (n = 21). Strong wear traces (> 350 µm) on antagonists and their adjacent teeth were found only in crowned groups. Abutment type influenced number and depth of wear facets on the antagonistic and adjacent teeth. CONCLUSION The clinically relevant model with human antagonistic and adjacent teeth allowed for a limited comparison of the wear situation. The total number of wear traces and strong wear on crowns, antagonistic and adjacent teeth were influenced by crown material.
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Affiliation(s)
- Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Frederik Schumann
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Verena Preis
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
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Rosentritt M, Koenig A, Kolbeck C, Krifka S, Hahnel S. Validating laboratory simulation with resin-based materials for temporary fixed denture prostheses - Results from clinical and laboratory trials. J Mech Behav Biomed Mater 2019; 101:103431. [PMID: 31585349 DOI: 10.1016/j.jmbbm.2019.103431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/02/2019] [Accepted: 09/12/2019] [Indexed: 11/13/2022]
Abstract
The aim of the current study was to relate an artificial aging protocol for the analysis of dental materials to their clinical performance. 20 fixed interim restorations (crowns and fixed denture prostheses (FDPs)) fabricated from two commercially available resin-based composites (RBCs) and a previous clinical trial served as templates for the fabrication of duplicate restorations. Duplicates were subjected to artificial aging using thermal cycling and mechanical loading. Subsequent to wear analysis, templates and duplicates were loaded to fracture and were examined using thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). For both RBCs, a relevant uptake of water was identified, which was more pronounced in the duplicates. Tribological analyses indicated relevant signs of wear in both templates and duplicates. While qualitative analyses indicated macroscopically similar wear traces in templates and duplicates, data showed that wear of FDPs was underrated in the laboratory analyses. The results of the current study suggest that chewing simulation allows a proper estimation of aging processes in materials for the fabrication of fixed interim restorations. However, simulation parameters should be continuously improved using data derived from clinical settings to enhance the quality of the simulation protocols.
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Affiliation(s)
- Martin Rosentritt
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Andreas Koenig
- Department of Prosthodontics and Materials Science, University of Leipzig, Leipzig, Germany
| | - Carola Kolbeck
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Sebastian Hahnel
- Department of Prosthodontics and Materials Science, University of Leipzig, Leipzig, Germany.
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Rosentritt M, Krifka S, Preis V, Strasser T. Dynamic fatigue of composite CAD/CAM materials. J Mech Behav Biomed Mater 2019; 98:311-316. [PMID: 31299592 DOI: 10.1016/j.jmbbm.2019.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 06/11/2019] [Accepted: 07/06/2019] [Indexed: 11/16/2022]
Affiliation(s)
- Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Verena Preis
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Thomas Strasser
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany.
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Abstract
This study investigated the handling properties and clinical performance of two commercially available resin materials with slight differences in filler composition for the fabrication of fixed interim restorations. In a dental university setting, patients requiring prosthetic treatment were supplied with fixed interim restorations fabricated from two commercially available resin materials. To clarify the handling properties of the resin materials, dentists and undergraduate students completed a questionnaire. Prior to insertion of the definitive restoration, the interim restorations were analyzed by calibrated examiners using a modification of the United States Public Health Service criteria. Eighty-two fixed interim restorations with a mean clinical service period of 44.5 (±28.3) days were included, including 39 single crowns, 30 fixed denture prostheses, 10 blocked crowns, and 3 partial coverage restorations. No significant differences between the two materials in the rating of their handling properties were identified, with the exception of the parameter "surface". Failures due to fractures were observed in 13% of the interim restorations. No significant differences between the materials in the rating of the clinical performance were identified. These results indicate that slight changes in the filler composition of commercial formulations account for few differences in handling properties and clinical performance.
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Affiliation(s)
- Sebastian Hahnel
- Department of Prosthodontics and Materials Science, University of Leipzig
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, Regensburg University Medical Center
| | - Michael Behr
- Department of Prosthetic Dentistry, Regensburg University Medical Center
| | - Carola Kolbeck
- Department of Prosthetic Dentistry, Regensburg University Medical Center
| | - Reinhold Lang
- Department of Prosthetic Dentistry, Regensburg University Medical Center
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, Regensburg University Medical Center
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Rosentritt M, Preis V, Behr M, Krifka S. In-vitro performance of CAD/CAM crowns with insufficient preparation design. J Mech Behav Biomed Mater 2019; 90:269-274. [DOI: 10.1016/j.jmbbm.2018.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/01/2018] [Accepted: 10/01/2018] [Indexed: 11/17/2022]
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Krifka S, Preis V, Rosentritt M. Effect of Decontamination and Cleaning on the Shear Bond Strength of High Translucency Zirconia. Dent J (Basel) 2017; 5:dj5040032. [PMID: 29563438 PMCID: PMC5806969 DOI: 10.3390/dj5040032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/30/2017] [Accepted: 11/09/2017] [Indexed: 11/21/2022] Open
Abstract
(1) Background: This study evaluated the bonding performance of high translucency zirconia after diverse surficial decontamination and cleaning procedures. (2) Methods: High translucency zirconia (LavaTM Esthetic) specimens (2.0 mm × 20 mm × 10 mm) were exposed to different surface treatments prior to bonding to CoCr cylinders (d = 5 mm, height = 3 mm). All surfaces were sandblasted (40 µm aluminum oxide, 2 bar) and treated with alcohol (al), saliva (s), saliva + water (sw), or saliva + NaOCl + water (sn) before bonding was performed with the following adhesive luting systems: RelyXTM Unicem 2 (RX), ScotchbondTM Universal (SBU) + RelyXTM Ultimate (RU) or Monobond Plus (MP) + Multilink® Automix (ML). After 24 h, thermocycling (TC:12,000 × 5 °C/55 °C) and 90 days of storage at 37 °C in distilled water, the shear bond strength (SBS) was evaluated according to ISO/TS 11,405:2015. Failure modes along bonding areas were characterized. Means and standard deviations (n = 10 per group) were determined and statistically analyzed with one-way ANOVA/Bonferroni (α = 0.05). (3) Results: The SBS after 24 h varied between 3.5 (sRX) and 69.4 MPa (snMP + ML). Values from 0 (sRX) to 70.3 MPa (swRX) were found after TC. Data after 90 days of storage showed the lowest values for sRX (0 MPa) and the highest values for alSBU + RU (75.5 MPa). Adhesive failure was noted at all aging conditions. (4) Conclusions: SBU + RU or RX and MP + ML including saliva decontamination of the ceramic surface with water or NaOCl + water allow efficient bonding to LavaTM Esthetic.
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Affiliation(s)
- Stephanie Krifka
- Department of Prosthetic Dentistry, University Hospital Regensburg, 93051 Regensburg, Germany.
| | - Verena Preis
- Department of Prosthetic Dentistry, University Hospital Regensburg, 93051 Regensburg, Germany.
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, University Hospital Regensburg, 93051 Regensburg, Germany.
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Schweikl H, Widbiller M, Krifka S, Klement J, Petzel C, Bolay C, Hiller KA, Buchalla W. Interaction between LPS and a dental resin monomer on cell viability in mouse macrophages. Dent Mater 2016; 32:1492-1503. [PMID: 27671463 DOI: 10.1016/j.dental.2016.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 04/26/2016] [Accepted: 09/03/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Lipopolysaccharide (LPS) from cariogenic microorganisms and resin monomers like HEMA (2-hydroxyethyl methacrylate) included in dentin adhesive are present in a clinical situation in deep dentinal cavity preparations. Here, cell survival, expression of proteins related to redox homeostasis, and viability of mouse macrophages exposed to LPS and HEMA were analyzed with respect to the influence of oxidative stress. METHODS Cell survival of RAW264.7 mouse macrophages was determined using a crystal violet assay, protein expression was detected by Western blotting, and HEMA- or LPS-induced apoptosis (cell viability) was analyzed by flow cytometry. Cells were exposed to HEMA (0-8mM), LPS (0.1μg/ml) or combinations of both substances for 24h. The influence of mitogen-activated protein kinases (MAPK) was analyzed using the specific inhibitors PD98059 (ERK1/2), SB203580 (p38) or SP600125 (JNK), and oxidative stress was identified by the antioxidant N-acetylcysteine (NAC). RESULTS Cell survival was reduced by HEMA. LPS, however, increased cell survival from 29% in cultures exposed to 8mM HEMA, to 46% in cultures co-exposed to 8mM HEMA/LPS. Notably, LPS-induced apoptosis was neutralized by 4-6mM HEMA but apoptosis caused by 8mM HEMA was counteracted by LPS. Expression of NOS (nitric oxide synthase), p47phox and p67phox subunits of NADPH oxidase, catalase or heme oxygenase (HO-1) was associated with HEMA- or LPS-induced apoptosis. While no influence of MAPK was detected, NAC inhibited cytotoxic effects of HEMA. SIGNIFICANCE HEMA- and LPS-triggered pathways may induce apoptosis and interfere with physiological tissue responses as a result of the differential formation of oxidative stress.
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Affiliation(s)
- Helmut Schweikl
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany.
| | - Matthias Widbiller
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Stephanie Krifka
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Johannes Klement
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Christine Petzel
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Carola Bolay
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Karl-Anton Hiller
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
| | - Wolfgang Buchalla
- Department of Conservative Dentistry and Periodontology, University Hospital, University of Regensburg, D-93042 Regensburg, Germany
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Van Landuyt KL, Krifka S, Hiller KA, Bolay C, Waha C, Van Meerbeek B, Schmalz G, Schweikl H. Evaluation of cell responses toward adhesives with different photoinitiating systems. Dent Mater 2015; 31:916-27. [PMID: 26026799 DOI: 10.1016/j.dental.2015.04.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 03/13/2015] [Accepted: 04/28/2015] [Indexed: 01/01/2023]
Abstract
OBJECTIVES The photoinitiator diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) is more reactive than a camphorquinone/amine (CQ) system, and TPO-based adhesives obtained a higher degree of conversion (DC) with fewer leached monomers. The hypothesis tested here is that a TPO-based adhesive is less toxic than a CQ-based adhesive. METHODS A CQ-based adhesive (SBU-CQ) (Scotchbond Universal, 3M ESPE) and its experimental counterpart with TPO (SBU-TPO) were tested for cytotoxicity in human pulp-derived cells (tHPC). Oxidative stress was analyzed by the generation of reactive oxygen species (ROS) and by the expression of antioxidant enzymes. A dentin barrier test (DBT) was used to evaluate cell viability in simulated clinical circumstances. RESULTS Unpolymerized SBU-TPO was significantly more toxic than SBU-CQ after a 24h exposure, and TPO alone (EC50=0.06mM) was more cytotoxic than CQ (EC50=0.88mM), EDMAB (EC50=0.68mM) or CQ/EDMAB (EC50=0.50mM). Cultures preincubated with BSO (l-buthionine sulfoximine), an inhibitor of glutathione synthesis, indicated a minor role of glutathione in cytotoxic responses toward the adhesives. Although the generation of ROS was not detected, a differential expression of enzymatic antioxidants revealed that cells exposed to unpolymerized SBU-TPO or SBU-CQ are subject to oxidative stress. Polymerized SBU-TPO was more cytotoxic than SBU-CQ under specific experimental conditions only, but no cytotoxicity was detected in a DBT with a 200μm dentin barrier. SIGNIFICANCE Not only DC and monomer-release determine the biocompatibility of adhesives, but also the cytotoxicity of the (photo-)initiator should be taken into account. Addition of TPO rendered a universal adhesive more toxic compared to CQ; however, this effect could be annulled by a thin dentin barrier.
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Affiliation(s)
- Kirsten L Van Landuyt
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany; KU Leuven BIOMAT, Department of Oral Health Sciences, University of Leuven & Dentistry University Hospitals Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium.
| | - Stephanie Krifka
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany
| | - Karl-Anton Hiller
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany
| | - Carola Bolay
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany
| | - Claudia Waha
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany
| | - Bart Van Meerbeek
- KU Leuven BIOMAT, Department of Oral Health Sciences, University of Leuven & Dentistry University Hospitals Leuven, Kapucijnenvoer 7, 3000 Leuven, Belgium
| | - Gottfried Schmalz
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany; School of Dental Medicine -ZMK Bern, University of Bern, Freiburgstrasse 7, 3010 Bern, Switzerland
| | - Helmut Schweikl
- Department of Operative Dentistry and Periodontology, University Hospital Regensburg, D-93042, 93042 Regensburg, Germany
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Krifka S, Spagnuolo G, Schmalz G, Schweikl H. A review of adaptive mechanisms in cell responses towards oxidative stress caused by dental resin monomers. Biomaterials 2013; 34:4555-63. [DOI: 10.1016/j.biomaterials.2013.03.019] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/09/2013] [Indexed: 12/28/2022]
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Krifka S, Hiller KA, Spagnuolo G, Jewett A, Schmalz G, Schweikl H. The influence of glutathione on redox regulation by antioxidant proteins and apoptosis in macrophages exposed to 2-hydroxyethyl methacrylate (HEMA). Biomaterials 2012; 33:5177-86. [DOI: 10.1016/j.biomaterials.2012.04.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 04/02/2012] [Indexed: 01/08/2023]
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Krifka S, Federlin M, Hiller KA, Schmalz G. Microleakage of silorane- and methacrylate-based class V composite restorations. Clin Oral Investig 2011; 16:1117-24. [PMID: 21947906 DOI: 10.1007/s00784-011-0619-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 09/09/2011] [Indexed: 11/26/2022]
Abstract
The marginal integrity of class V restorations in a silorane- and a group of methacrylate-based composite resins with varying viscosities was tested in the present study. Different adhesives (OptiBond FL, KerrHawe; AdheSE One, Vivadent; or Silorane System Adhesive, 3M ESPE) were applied to 168 standardized class V cavities. The cavities (n = 12) were filled with a wide range of different viscous composite resins: Filtek Silorane, 3M ESPE; els and els flow, Saremco; Tetric EvoCeram and Tetric EvoFlow, Vivadent; Grandio, Voco; and Ultraseal XT Plus, Ultradent. Microleakage of the restoration was assessed by dye penetration (silver staining) on multiple sections with and without thermocycling and mechanical loading (TCML: 5,000 × 5-55°C; 30 s/cycle; 500,000 × 72.5 N, 1.6 Hz). Data were statistically analyzed with the Mann-Whitney U test and the Error Rates Method (ERM). The silorane-based composite resin yielded the lowest dye penetration after TCML. Microleakage of methacrylate-based composite restorations, in general (ERM), was statistically significantly influenced by the adhesive system, Moreover, dye penetration at enamel margins was significantly lower than dye penetration at dentin margins. The chemical basis of composite resins and adjacent tooth substance seems to strongly influence marginal sealing of class V restorations for methacrylate-based materials. Moreover, the steps of dental adhesives used affected marginal integrity. The silorane-based composite resin evaluated in the present study exhibits the best marginal seal. The three-step adhesive yielded better marginal sealing than the one-step adhesive for methacrylate-based class V composite restorations.
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Affiliation(s)
- Stephanie Krifka
- Department of Operative Dentistry and Periodontology, University of Regensburg Medical Centre, Franz Josef Strauß Allee 11, 93042 Regensburg, Germany.
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Abstract
Unreacted monomers released from dental resin-based composites at non-cytotoxic concentrations cause a depletion of glutathione and an increase of reactive oxygen species (ROS), leading to, e.g., DNA damage and apoptosis. ROS-sensitive MAP-kinases are activated by HEMA and TEGDMA. MAP-kinases are also involved in the bacteria-triggered cell responses of the innate immune system, e.g., after bacterial lipopolysaccharide (LPS) binding to the Toll-like receptor (TLR) 4. Therefore, both bacteria and monomers imply environmental stress to pulp tissue, and they may influence the target cell reactions in a combined way. In macrophages, cell-surface antigens and cytokines were up-regulated after exposure to LPS, but TEGDMA caused a significant down-regulation. Regulation was dependent on exposure time, indicating that LPS and TEGDMA act differently on MAP-kinases. Furthermore, the cell type played a decisive role. Inhibition of the immune response may result in a decrease in inflammatory symptoms and/or a reduced defense capacity against bacteria.
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Affiliation(s)
- G. Schmalz
- Department of Operative Dentistry and Periodontology, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany
| | - S. Krifka
- Department of Operative Dentistry and Periodontology, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany
| | - H. Schweikl
- Department of Operative Dentistry and Periodontology, University Medical Centre Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany
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Krifka S, Seidenader C, Hiller KA, Schmalz G, Schweikl H. Oxidative stress and cytotoxicity generated by dental composites in human pulp cells. Clin Oral Investig 2011; 16:215-24. [PMID: 21243381 DOI: 10.1007/s00784-010-0508-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 12/30/2010] [Indexed: 12/11/2022]
Abstract
Dental composites are a source of residual monomers that are released into the oral environment. Since monomers act on cultured cells through reactive oxygen species (ROS), we hypothesized that composites generate ROS associated with cytotoxicity. Human pulp-derived cells were exposed to extracts of methacrylate-based materials including triethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate-free composites (Tetric Ceram, Tetric EvoCeram, els, els flow, Solitaire 2) and a silorane-based composite (Hermes III). The materials were polymerized in the presence and absence of a polyester film and then extracted in culture medium. The generation of ROS was measured by flow cytometry, and cytotoxicity was determined as well. Methacrylate-based composites reduced cell survival but varied in efficiency. Undiluted extracts of Solitaire 2 specimens prepared in the absence of a polyester film reduced cell survival to 26% compared with untreated cultures. Cytotoxicity was reduced when specimens were covered with a polyester film during preparation. Cytotoxicity of the composites was ranked as follows: Solitaire 2 >> els flow > Tetric Ceram = Tetric EvoCeram = els > Hermes III. The generation of ROS followed the same pattern as detected with cytotoxic effects. A positive correlation was found between ROS production and cell survival caused by extracts made from materials not covered with a polyester film. These findings suggest that components released from composites affect cellular signaling networks through ROS formation. Regenerative and reparative capacities of the dentine-pulp complex may be impaired by biologically active resin monomers released from composite restorations.
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Affiliation(s)
- Stephanie Krifka
- Department of Operative Dentistry and Periodontology, University of Regensburg Medical Centre, Franz Josef Strauss Allee 11, 93042, Regensburg, Germany
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Krifka S, Petzel C, Bolay C, Hiller KA, Spagnuolo G, Schmalz G, Schweikl H. Activation of stress-regulated transcription factors by triethylene glycol dimethacrylate monomer. Biomaterials 2010; 32:1787-95. [PMID: 21145583 DOI: 10.1016/j.biomaterials.2010.11.031] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 11/14/2010] [Indexed: 12/13/2022]
Abstract
Triethylene glycol dimethacrylate (TEGDMA) is a resin monomer available for short exposure scenarios of oral tissues due to incomplete polymerization processes of dental composite materials. The generation of reactive oxygen species (ROS) in the presence of resin monomers is discussed as a common mechanism underlying cellular reactions as diverse as disturbed responses of the innate immune system, inhibition of dentin mineralization processes, genotoxicity and a delayed cell cycle. Yet, the signaling pathway through a network of proteins that finally initiates the execution of monomer-induced specific cell responses is unknown so far. The aim of the present study was to extend the knowledge of molecular mechanisms of monomer-induced cell death as a basis for reasonable therapy strategies. Thus, the monomer-induced expression and phosphorylation of stress-related transcription factors was analyzed in various cell lines. The time-related induction of apoptosis was investigated as well. The expression of p53 increased in HeLa cell cultures treated with camptothecin (positive control) for 24h, and the formation of p53Ser15 and p53Ser46 was detected in cell nuclei by Western blotting. TEGDMA (3 mm) appeared to stimulate p53 expression only slightly, but increased p21 expression was found in cell nuclei and cytoplasm. Both camptothecin and TEGDMA increased p53 expression to some extent in the nuclear fraction in human transformed pulp-derived cells (tHPC), and similar effects were detected in RAW264.7 macrophages. No clear induction of c-Jun and phospho-c-Jun by TEGDMA was detected in HeLa cell nuclei, and the expression of ATF-2 and phospho-ATF-2 was inhibited in the presence of the monomer. ATF-3 expression was found only in the nuclear fraction of camptothecin-treated HeLa cultures. TEGDMA seemed to inhibit the formation of phospho-c-Jun and phospho-ATF-2 in tHPC, and the monomer acted negatively on the expression of c-Jun, ATF-2 and ATF-3 in RAW264.7 macrophages. These changes in the expression and activation of stress-related transcription factors were time-related to the induction of apoptosis by TEGDMA in all cell lines. The present study provides experimental evidence that TEGDMA interferes with the regulation of cellular pathways through transcription factors activated as a consequence of DNA damage like p53 or initiated downstream of MAPK (mitogen-activated protein kinases) like c-Jun, ATF-2 and ATF-3. The direct causal correlation between DNA damage, activation or inhibition of MAPKs and transcription factors, and apoptosis is under current investigation. However, the induction of apoptosis in different cell lines in the presence of monomers like TEGDMA may be subject to a higher level of complexity than currently suggested by simple linear models.
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Affiliation(s)
- Stephanie Krifka
- Department of Operative Dentistry and Periodontology, University of Regensburg, D-93042 Regensburg, Germany
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Krifka S, Petzel C, Hiller KA, Frank EM, Bosl C, Spagnuolo G, Reichl FX, Schmalz G, Schweikl H. Resin monomer-induced differential activation of MAP kinases and apoptosis in mouse macrophages and human pulp cells. Biomaterials 2010; 31:2964-75. [DOI: 10.1016/j.biomaterials.2010.01.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 01/03/2010] [Indexed: 12/20/2022]
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Krifka S, Anthofer T, Fritzsch M, Hiller KA, Schmalz G, Federlin M. Ceramic inlays and partial ceramic crowns: influence of remaining cusp wall thickness on the marginal integrity and enamel crack formation in vitro. Oper Dent 2009; 34:32-42. [PMID: 19192835 DOI: 10.2341/08-34] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
No information is currently available about what the critical cavity wall thickness is and its influence upon 1) the marginal integrity of ceramic inlays (CI) and partial ceramic crowns (PCC) and 2) the crack formation of dental tissues. This in vitro study of CI and PCC tested the effects of different remaining cusp wall thicknesses on marginal integrity and enamel crack formation. CI (n = 25) and PCC (n = 26) preparations were performed in extracted human molars. Functional cusps of CI and PCC were adjusted to a 2.5 mm thickness; for PCC, the functional cusps were reduced to a thickness of 2.0 mm. Non-functional cusps were adjusted to wall thicknesses of 1) 1.0 mm and 2) 2.0 mm. Ceramic restorations (Vita Mark II, Cerec3 System) were fabricated and adhesively luted to the cavities with Excite/Variolink II. The specimens were exposed to thermocycling and central mechanical loading (TCML: 5000 x 5 degrees C-55 degrees C; 30 seconds/cycle; 500000 x 72.5N, 1.6Hz). Marginal integrity was assessed by evaluating a) dye penetration (fuchsin) on multiple sections after TCML and by using b) quantitative margin analysis in the scanning electron microscope (SEM) before and after TCML. Ceramic- and tooth-luting agent interfaces (LA) were evaluated separately. Enamel cracks were documented under a reflective light microscope. The data were statistically analyzed with the Mann Whitney U-test (alpha = 0.05) and the Error Rates Method (ERM). Crack formation was analyzed with the Chi-Square-test (alpha = 0.05) and ERM. In general, the remaining cusp wall thickness, interface, cavity design and TCML had no statistically significant influence on marginal integrity for both CI and PCC (ERM). Single pairwise comparisons showed that the CI and PCC of Group 2 had a tendency towards less microleakage along the dentin/LA interface than Group 1. Cavity design and location had no statistically significant influence on crack formation, but the specimens with 1.0 mm of remaining wall thickness had statistically significantly more crack formation after TCML than the group with 2.0 mm of remaining cusp wall thickness for CI. The remaining cusp wall thickness of non-functional cusps of adhesively bonded restorations (especially for CI) should have a thickness of at least 2.0 mm to avoid cracks and marginal deficiency at the dentin/LA interface.
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Affiliation(s)
- Stephanie Krifka
- Department of Operative Dentistry and Periodontology, University Clinics, Regensburg, Germany.
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Krifka S, Stangl M, Wiesbauer S, Hiller KA, Schmalz G, Federlin M. Influence of different cusp coverage methods for the extension of ceramic inlays on marginal integrity and enamel crack formation in vitro. Clin Oral Investig 2009; 13:333-41. [DOI: 10.1007/s00784-008-0239-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 12/03/2008] [Indexed: 11/28/2022]
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Oliver R, Kersten H, Vinkka-Puhakka H, Alpasan G, Bearn D, Cema I, Delap E, Dummer P, Goulet JP, Gugushe T, Jeniati E, Jerolimov V, Kotsanos N, Krifka S, Levy G, Neway M, Ogawa T, Saag M, Sidlauskas A, Skaleric U, Vervoorn M, White D. Curriculum structure: principles and strategy. Eur J Dent Educ 2008; 12 Suppl 1:74-84. [PMID: 18289270 DOI: 10.1111/j.1600-0579.2007.00482.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This report provides general guidelines for the structure of a curriculum, followed by specific advice on the principles of learning and teaching, the process of restructuring and change leadership and management. It provides examples of several educational philosophies, including vertical and horizontal integration. It discusses the use of competence, learning outcomes, level of degree and assessment and provides a number of recommendations. It does not seek to be prescriptive of time allocation to disciplines within a curriculum. Although this report has been written primarily for those who will develop an undergraduate curriculum, the information may be sufficiently generic to apply to the recent development in graduate entry ('shortened dental' or 'accelerated') courses and to postgraduate degree planning and higher education certificate or diploma courses for other dental care professionals (auxiliaries). The report may have a European bias as progress is made to converge and enhance educational standards in 29 countries with different educational approaches - a microcosm of global collaboration.
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Affiliation(s)
- R Oliver
- Cardiff University, Cardiff, UK.
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Federlin M, Krifka S, Herpich M, Hiller KA, Schmalz G. Partial Ceramic Crowns: Influence of Ceramic Thickness, Preparation Design and Luting Material on Fracture Resistance and Marginal Integrity In Vitro. Oper Dent 2007; 32:251-60. [PMID: 17555176 DOI: 10.2341/06-70] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
For fracture resistance and the marginal integrity of adhesively bonded partial ceramic crowns (PCC), the choice of ceramic thickness and luting material are more important than preparation design. PCC fabricated from industrially sintered feldspathic ceramic should have at least a thickness of 1.5–2.0 mm in stress bearing areas.
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Affiliation(s)
- Marianne Federlin
- University of Regensburg, Dental School, Department of Operative Dentistry and Periodontology, Regensburg, Germany
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