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Peeters WM, Gram M, Dias GJ, Vissers MCM, Hampton MB, Dickerhof N, Bekhit AE, Black MJ, Oxbøll J, Bayer S, Dickens M, Vitzel K, Sheard PW, Danielson KM, Hodges LD, Brønd JC, Bond J, Perry BG, Stoner L, Cornwall J, Rowlands DS. Changes to insulin sensitivity in glucose clearance systems and redox following dietary supplementation with a novel cysteine-rich protein: A pilot randomized controlled trial in humans with type-2 diabetes. Redox Biol 2023; 67:102918. [PMID: 37812879 PMCID: PMC10570009 DOI: 10.1016/j.redox.2023.102918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/02/2023] [Indexed: 10/11/2023] Open
Abstract
We recently developed a novel keratin-derived protein (KDP) rich in cysteine, glycine, and arginine, with the potential to alter tissue redox status and insulin sensitivity. The KDP was tested in 35 human adults with type-2 diabetes mellitus (T2DM) in a 14-wk randomised controlled pilot trial comprising three 2×20 g supplemental protein/day arms: KDP-whey (KDPWHE), whey (WHEY), non-protein isocaloric control (CON), with standardised exercise. Outcomes were measured morning fasted and following insulin-stimulation (80 mU/m2/min hyperinsulinaemic-isoglycaemic clamp). With KDPWHE supplementation there was good and very-good evidence for moderate-sized increases in insulin-stimulated glucose clearance rate (GCR; 26%; 90% confidence limits, CL 2%, 49%) and skeletal-muscle microvascular blood flow (46%; 16%, 83%), respectively, and good evidence for increased insulin-stimulated sarcoplasmic GLUT4 translocation (18%; 0%, 39%) vs CON. In contrast, WHEY did not effect GCR (-2%; -25%, 21%) and attenuated HbA1c lowering (14%; 5%, 24%) vs CON. KDPWHE effects on basal glutathione in erythrocytes and skeletal muscle were unclear, but in muscle there was very-good evidence for large increases in oxidised peroxiredoxin isoform 2 (oxiPRX2) (19%; 2.2%, 35%) and good evidence for lower GPx1 concentrations (-40%; -4.3%, -63%) vs CON; insulin stimulation, however, attenuated the basal oxiPRX2 response (4%; -16%, 24%), and increased GPx1 (39%; -5%, 101%) and SOD1 (26%; -3%, 60%) protein expression. Effects of KDPWHE on oxiPRX3 and NRF2 content, phosphorylation of capillary eNOS and insulin-signalling proteins upstream of GLUT4 translocation AktSer437 and AS160Thr642 were inconclusive, but there was good evidence for increased IRSSer312 (41%; 3%, 95%), insulin-stimulated NFκB-DNA binding (46%; 3.4%, 105%), and basal PAK-1Thr423/2Thr402 phosphorylation (143%; 66%, 257%) vs WHEY. Our findings provide good evidence to suggest that dietary supplementation with a novel edible keratin protein in humans with T2DM may increase glucose clearance and modify skeletal-muscle tissue redox and insulin sensitivity within systems involving peroxiredoxins, antioxidant expression, and glucose uptake.
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Affiliation(s)
- W M Peeters
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand; School of Biomedical, Nutritional and Sport Science, Newcastle University, United Kingdom
| | - M Gram
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand
| | - G J Dias
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - M C M Vissers
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - M B Hampton
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - N Dickerhof
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - A E Bekhit
- Department of Food Sciences, University of Otago, Dunedin, New Zealand
| | - M J Black
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand
| | - J Oxbøll
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand
| | - S Bayer
- Centre for Free Radical Research, Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
| | - M Dickens
- School of Health Sciences, Massey University, Wellington, Auckland, New Zealand
| | - K Vitzel
- School of Health Sciences, Massey University, Wellington, Auckland, New Zealand
| | - P W Sheard
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - K M Danielson
- Department of Anaesthesiology and Surgery, University of Otago, Wellington, New Zealand
| | - L D Hodges
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand
| | - J C Brønd
- Department of Sports Science and Clinical Biomechanics, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - J Bond
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand
| | - B G Perry
- School of Health Sciences, Massey University, Wellington, Auckland, New Zealand
| | - L Stoner
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, USA
| | - J Cornwall
- Centre for Early Learning in Medicine, University of Otago, Dunedin, New Zealand
| | - D S Rowlands
- Metabolic and Microvascular Laboratory, School of Sport, Exercise and Nutrition, Massey University, Wellington, Auckland, New Zealand.
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Enkling N, Marder M, Bayer S, Götz W, Stoilov M, Kraus D. Soft tissue response to different abutment materials: A controlled and randomized human study using an experimental model. Clin Oral Implants Res 2022; 33:667-679. [PMID: 35467040 DOI: 10.1111/clr.13932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 04/29/2021] [Revised: 02/01/2022] [Accepted: 04/12/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Aim of this study was to compare the soft-tissue response to implant abutments made of titanium, zirconia, zirconia veneered with feldspar ceramics and PEEK by various clinical, histological, microbiological and molecular biological markers in an experimental model. MATERIALS AND METHODS 40 experimental one-piece healing abutments of four different materials were mounted on bone-level implants in 20 volunteering patients (split-mouth design). After a three months period of open healing, clinical parameters at the abutments were assessed and adjacent mucosa was sampled for inflammatory cytokine mRNA-concentrations and histological analysis by a novel method. In addition, PISF-samples were obtained for the analysis of periodonto-pathogenic bacteria counts and active MMP-8 levels. Marginal bone level change was measured by intra oral radiographs. RESULTS Abutments of the different materials did not exhibit significant differences regarding clinical parameters, pathogenic bacteria counts or pro-inflammatory cytokine concentrations. Likewise, no significant differences were detected regarding soft tissue morphology or bone level change. Compared to titanium abutments, significantly less mononuclear inflammatory cells were detected in the mucosa at abutments made of zirconia veneered with feldspar ceramics. CONCLUSIONS All examined abutment materials exhibited a similar soft tissue response compared to titanium and histological data did not reveal early signs of elevated inflammation caused by PEEK- and feldspar-veneered zirconia abutments. Due to the short observation period and the small sample size, a final conclusion on the long term suitability of those abutment materials cannot be drawn. However, based on the presented data, we consider further studies on that subject as appropriate.
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Affiliation(s)
- Norbert Enkling
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn.,Department of Reconstructive Dentistry and Gerodontology, University of Bern
| | - Michael Marder
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn
| | - Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn
| | - Werner Götz
- Department of Orthodontics, University of Bonn
| | - Milan Stoilov
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn
| | - Dominik Kraus
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn
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Kraus D, Götz W, Bayer S, Frentzen M, Marder M, Albrecht D, Enkling N. Novel method to obtain human non-separated histological samples for the assessment of peri-implant soft tissue response: A feasibility study. Clin Oral Implants Res 2021; 32:401-409. [PMID: 33445211 DOI: 10.1111/clr.13710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 07/07/2020] [Revised: 12/19/2020] [Accepted: 01/01/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To introduce a standardized and less invasive clinical model that provides histological information on the abutment-mucosa interface in humans. MATERIALS AND METHODS New experimental healing abutments were left in an open healing position on bone-level implants in the interforaminal region of the mandibles in six edentulous patients. The one-piece abutments were hollow cylinder-shaped with two lateral openings that allow for ingrowth of the peri-implant mucosa into the central abutment cavity. After three months of healing, abutments and ingrown mucosa were sampled and processed for histological analysis in a non-separated resin-embedding technique. To test the validity of the new model, the ingrown tissue was compared to the peri-implant mucosa around the same samples. RESULTS None of the experimental abutments exhibited signs of failure, and all samples showed mucosal ingrowth to the inner-abutment cavity. Comparison of ingrown tissue and peri-implant mucosa revealed no significant differences regarding the traits: tissue morphology, quality of collagen fibers, and adherence to the abutment. Ingrown mucosa exhibited a tendency for higher leukocyte infiltration. CONCLUSIONS The presented model is a promising approach to reduce invasiveness during the sampling process for human non-separated abutment biopsies.
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Affiliation(s)
- Dominik Kraus
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn, Bonn, Germany
| | - Werner Götz
- Department of Orthodontics, University of Bonn, Bonn, Germany
| | - Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn, Bonn, Germany
| | - Matthias Frentzen
- Department of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Michael Marder
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn, Bonn, Germany
| | | | - Norbert Enkling
- Department of Prosthodontics, Preclinical Education and Material Sciences, University of Bonn, Bonn, Germany.,Department of Reconstructive Dentistry and Gerodontology, University of Berne, Bern, Switzerland
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Yilmaz N, Demirtas N, Kazancioglu HO, Bayer S, Acar AH, Mihmanli A. The efficacy of hyaluronic acid in postextraction sockets of impacted third molars: A pilot study. Niger J Clin Pract 2018; 20:1626-1631. [PMID: 29378998 DOI: 10.4103/1119-3077.224131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE This study aims to evaluate the effectiveness of local hyaluronic acid (HA) administration to surgically remove impacted third molar sockets and measure pain, swelling, and trismus. MATERIALS AND METHODS The study included a total of 25 healthy patients aged 18-29 years with asymptomatic bilaterally impacted lower third molars. All cases have been performed under local anesthesia. In the study group, 0.8% HA (Gengigel®) was applied in the postextraction sockets of the right third molars and in the control group nothing was applied to the extraction sockets of the left third molars. Postoperative pain, trismus, and swelling were evaluated on the 1st, 3rd, and 7th postoperative days. RESULTS No difference was determined between groups in facial swelling and maximum mouth opening. However, the amount of pain significantly reduced in HA groups according to visual analog scale (P = 0.001). CONCLUSION The results of this study showed that HA can produce an analgesic action in postextraction sockets after surgical removal of impacted teeth and therefore it has a clinical benefit to reduce usage of nonsteroidal anti-inflammatory drugs after dentoalveolar surgery.
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Affiliation(s)
- N Yilmaz
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
| | - N Demirtas
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
| | - H O Kazancioglu
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
| | - S Bayer
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
| | - A H Acar
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
| | - A Mihmanli
- Deparment of Oral and Maxillofacial Surgery, Bezmialem Vakif University, Faculty of Dentistry, Istanbul, Turkey
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de Cazes M, Belleville MP, Petit E, Salomo M, Bayer S, Czaja R, De Gunzburg J, Sanchez-Marcano J. Erythromycin degradation by esterase (EreB) in enzymatic membrane reactors. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.06.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Resetkova N, Sakkas D, Bayer S, Penzias A, Alper M. Home-based ultrasound monitoring for in vitro fertilization is a feasible method of in cycle monitoring. Fertil Steril 2016. [DOI: 10.1016/j.fertnstert.2016.07.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nierlich J, Papageorgiou SN, Bourauel C, Hültenschmidt R, Bayer S, Stark H, Keilig L. Corrosion behavior of dental alloys used for retention elements in prosthodontics. Eur J Oral Sci 2016; 124:287-94. [PMID: 27061513 DOI: 10.1111/eos.12267] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2016] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to investigate the corrosion behavior of 10 different high noble gold-based dental alloys, used for prosthodontic retention elements, according to ISO 10271. Samples of 10 high-noble and noble gold-based dental alloys were subjected to: (i) static immersion tests with subsequent analysis of ion release for eight different elements using mass spectrometry; (ii) electrochemical tests, including open-circuit potential and potentiodynamic scans; and (iii) scanning electron microscopy, followed by energy-dispersive X-ray microscopy. The results were analyzed using one-way ANOVA and Sidak multiple-comparisons post-hoc test at a level of significance of α = 0.05. Significant differences were found among the 10 alloys studied for all ions (P < 0.001). The potentiodynamic analysis showed values from -82.5 to 102.8 mV for the open-circuit potential and from 566.7 to 1367.5 mV for the breakdown potential. Both the open-circuit and the breakdown potential varied considerably among these alloys. Scanning electron microscopy analysis confirmed the existence of typically small-diameter corrosion defects, whilst the energy-dispersive X-ray analysis found no significant alteration in the elemental composition of the alloys. The results of this study reveal the variability in the corrosive resistance among the materials used for retention elements in prosthodontics.
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Affiliation(s)
- Judith Nierlich
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Spyridon N Papageorgiou
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Orthodontics, School of Dentistry, University of Bonn, Bonn, Germany
| | - Christoph Bourauel
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany
| | - Robert Hültenschmidt
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Stefan Bayer
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Helmut Stark
- Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
| | - Ludger Keilig
- Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany.,Department of Prosthetic Dentistry, Preclinical Education and Materials Science, School of Dentistry, University of Bonn, Bonn, Germany
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Gölz L, Bayer S, Keilig L, Jäger A, Stark H, Bourauel C, Götz W, Frede S, Winter J, Kraus D. Possible implications of Ni(II) on oral IL-1β-induced inflammatory processes. Dent Mater 2014; 30:1325-35. [PMID: 25447842 DOI: 10.1016/j.dental.2014.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [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: 11/09/2013] [Revised: 05/15/2014] [Accepted: 09/23/2014] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Nickel (Ni) is one of the main metal elements in orthodontic and prosthetic devices. Different effects of Ni are described ranging from an induction of local inflammation to allergy and cancerous/mutagenic properties. Inflammatory reactions are frequently observed in the oral cavity, but the interrelationship of Ni with those events is still unknown. Therefore, we focused on the impact of Ni on inflammation in vitro. METHODS In accordance to previous immersion tests of our lab, human gingival fibroblasts (HGFs) (n=6) were exposed to a pro-inflammatory environment using interleukin-1 beta (IL-1β) and additionally stimulated with different Ni(II) concentrations (400 and 4000ng/ml). At varying time points the expression of pro- and anti-inflammatory as well as matrix degeneration proteins, i.e. MMPs, were analyzed. Furthermore, proliferation assays, wound healing tests and the detection of NF-κB activation were conducted. Unstimulated HGFs served as control. RESULTS Our experiments showed that low clinical average Ni(II) levels did not alter pro-inflammatory cytokines significantly compared to control (p>0.05). Instead, a 10-fold higher dose up-regulated these mediators significantly in a time-dependent manner (p<0.01). This was even more pronounced combining both Ni(II) concentrations with an inflammatory condition (p<0.001), MMP expressions were in line with our findings (p<0.001). The mRNA data were supported by proliferation and wound closure assays (p<0.001). However, the combination of both stimuli induced contradictory results. Analyzing NF-κB activation revealed that our results may be in part attributed to NF-κB. SIGNIFICANCE Our in vitro study implicated that Ni(II) has various modifying effects on IL-1β-induced inflammatory processes depending on the concentration.
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Affiliation(s)
- Lina Gölz
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany.
| | - Stefan Bayer
- Department of Prosthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | | | - Andreas Jäger
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | - Helmut Stark
- Department of Prosthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | | | - Werner Götz
- Department of Orthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
| | - Stilla Frede
- Department of Anesthesiology and Intensive Care Medicine, University of Bonn, Bonn, Germany
| | - Jochen Winter
- Oral Cell Biology Group, Department of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Dominik Kraus
- Department of Prosthodontics, Center of Dento-Maxillo-Facial Medicine, University of Bonn, Bonn, Germany
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Abstract
In contrast with previous findings, triethylborane, BEt3, can act as a hydroborating reagent. Thus, the reactions of BEt3 with alkyn-1-yl(trichloro)silanes, di(alkyn-1-yl)dichlorosilanes, alkyn- 1-yl(dichloro)vinylsilanes, trichloro(vinyl)silane, and dichloro(methyl)vinylsilane for several days in excess BEt3 as the solvent at 100 - 120 °C were found to give exclusively products of 1,2- hydroboration. This unexpected behaviour was compared with that of tri-n-propylborane, BnPr3, and 9-borabicyclo[3.3.1]nonane, 9-BBN in analogous reactions, 9-BBN being a well established hydroborating reagent. All products were characterised by a consistent set of NMR data (1H, 11B, 13C and 29Si NMR).
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Affiliation(s)
- Bernd Wrackmeyer
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Ezzat Khan
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Stefan Bayer
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Khadija Shahid
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
- Department of Chemistry, Quaid-I-Azam University, Islamabad, Pakistan
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Khan E, Bayer S, Wrackmeyer B. Reactivity of Triethylborane towards Di(alkyn-1-yl)(chloro)silanes. Competition between 1,1-Organoboration and 1,2-Hydroboration. Zeitschrift für Naturforschung B 2014. [DOI: 10.1515/znb-2009-0107] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Reactions of di(alkyn-1-yl)(chloro)silanes, HSi(Cl)(C≡C-R)2, R1Si(Cl)(C≡C-R)2 or HSi(Cl)-(C≡C-R)C≡C-Rʹ, with an excess of triethylborane, BEt3, proceed slowly (several days) at 100 -120 °C. Twofold 1,1-organoboration of HSi(Cl)(C≡C-R)2 or HSi(Cl)(C≡C-R)C≡C-Rʹleads tosiloles, independent of R = nBu, tBu, SiMe3. This provides the most straightforward way to silolesbearing both a hydrogen and a chlorine at the silicon atom. However, in the cases of R = Ph, BEt3 actsas 1,2-hydroborating reagent in the intermolecular first step of the reaction, leading to 1-silacyclobutene derivatives. All siloles and 1-silacyclobutene derivatives were characterized by multinuclear NMR spectroscopy (1H, 11B, 13C and 29Si). Comparable 1-silacyclobutene derivatives were formed using 9-borabicyclo[3.3.1]nonane, 9-BBN, as a well established 1,2- hydroborating reagent
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Affiliation(s)
- Ezzat Khan
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Stefan Bayer
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
| | - Bernd Wrackmeyer
- Anorganische Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany
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Khan E, Bayer S, Wrackmeyer B. Syntheses of 1,1-Organo-substituted Silole Derivatives. 1,1-Ethylboration, 1,1-Vinylboration and Protodeborylation. Zeitschrift für Naturforschung B 2014. [DOI: 10.1515/znb-2009-0902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
1,1-Organoboration of dialkyn-1-ylsilanes using triethylborane, BEt3, and 9-ethyl-9-borabicyclo [3.3.1]nonane, Et-9-BBN, was carried out at elevated temperatures, 100 - 120 °C. These reactions afforded selectively silole derivatives bearing the dialkylboryl group in 3-position. The siloles are formed via intermolecular 1,1-alkylboration, followed by intramolecular 1,1-vinylboration. Two examples of boryl-substituted siloles were treated with an excess of acetic acid at ambient temperature to afford the respective protodeborylated compounds. All new compounds were characterized in solution by multinuclear magnetic resonance spectroscopy (1H, 13C, 11B and 29Si NMR).
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Affiliation(s)
- Ezzat Khan
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
- Department of Chemistry University of Malakand, Chakdara, Dir(Lower), N.W. F. P., Pakistan
| | - Stefan Bayer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Bernd Wrackmeyer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
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Wrackmeyer B, Bayer S, Tok OL, Klimkina EV, Milius W, Kempe R, Khan E. Alkynylsilanes and Alkynyl(vinyl)silanes. Synthesis,Molecular Structures and Multinuclear Magnetic Resonance Study. Zeitschrift für Naturforschung B 2014. [DOI: 10.1515/znb-2010-0609] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alkynylsilanes bearing one to four alkynyl groups at silicon, with organyl groups (Me, Ph, Vin), H, Cl at silicon, and with substituents H, nBu, tBu, Ph, C6H4-4-Me, 3-thienyl, CH2NMe2 at the C≡C bond, were prepared, and their 13C and 29Si NMR data are reported. The results of X-ray structure analyses of three representative derivatives [di(phenylethynyl)dimethylsilane, di(phenylethynyl) methyl(phenyl)silane, and tri(phenylethynyl)methylsilane] are presented. The chemistry of mono- and dialkynylsilanes was further developed to prepare compounds with alternating Si atoms and C≡C bonds, affording new dialkynylsilanes as well as numerous new vinylsilanes which have also been characterized by 13C and 29Si NMR spectroscopy in solution. In the case of ethynyl(triphenylsilylethynyl) dimethylsilane, the molecular structure was determined by X-ray diffraction.
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Affiliation(s)
- Bernd Wrackmeyer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Stefan Bayer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Oleg L. Tok
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Elena V. Klimkina
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Wolfgang Milius
- Anorganische Chemie I, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Rhett Kempe
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Ezzat Khan
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
- Department of Chemistry University of Malakand, Chakdara, Dir(Lower), N.W.F.P., Pakistan
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Enkling N, Jöhren P, Katsoulis J, Bayer S, Jervøe-Storm PM, Mericske-Stern R, Jepsen S. Influence of platform switching on bone-level alterations: a three-year randomized clinical trial. J Dent Res 2013; 92:139S-45S. [PMID: 24158333 DOI: 10.1177/0022034513504953] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The concept of platform switching has been introduced to implant dentistry based on clinical observations of reduced peri-implant crestal bone loss. However, published data are controversial, and most studies are limited to 12 months. The aim of the present randomized clinical trial was to test the hypothesis that platform switching has a positive impact on crestal bone-level changes after 3 years. Two implants with a diameter of 4 mm were inserted crestally in the posterior mandible of 25 patients. The intraindividual allocation of platform switching (3.3-mm platform) and the standard implant (4-mm platform) was randomized. After 3 months of submerged healing, single-tooth crowns were cemented. Patients were followed up at short intervals for monitoring of healing and oral hygiene. Statistical analysis for the influence of time and platform type on bone levels employed the Brunner-Langer model. At 3 years, the mean radiographic peri-implant bone loss was 0.69 ± 0.43 mm (platform switching) and 0.74 ± 0.57 mm (standard platform). The mean intraindividual difference was 0.05 ± 0.58 mm (95% confidence interval: -0.19, 0.29). Crestal bone-level alteration depended on time (p < .001) but not on platform type (p = .363). The present randomized clinical trial could not confirm the hypothesis of a reduced peri-implant crestal bone loss, when implants had been restored according to the concept of platform switching.
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Affiliation(s)
- N Enkling
- Department of Prosthodontics, University of Berne, Switzerland
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15
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Enkling N, Ueda T, Gholami H, Bayer S, Katsoulis J, Mericske-Stern R. Precision of fit and retention force of cast non-precious-crowns on standard titanium implant-abutment with different design and height. Clin Oral Implants Res 2013; 25:451-7. [DOI: 10.1111/clr.12167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Norbert Enkling
- Department of Prosthodontics; University of Bern; Bern Switzerland
- Department of Prosthodontics; Preclinical Education and Dental Material Science; University of Bonn; Bonn Germany
| | - Takayuki Ueda
- Department of Removable Prosthodontics and Gerodontology; Tokyo Dental College; Chiba Japan
| | - Hadi Gholami
- Department of Prosthodontics; University of Bern; Bern Switzerland
| | - Stefan Bayer
- Department of Prosthodontics; University of Bern; Bern Switzerland
- Department of Prosthodontics; Preclinical Education and Dental Material Science; University of Bonn; Bonn Germany
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Binner C, Dohmen PM, Binner-Oussenek K, Bayer S, Borger MA, Misfeld M, Mohr FW. Splenectomy in active infective endocarditis: Simultaneous or two stage procedure? Thorac Cardiovasc Surg 2013. [DOI: 10.1055/s-0032-1332399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Bayer S, Kraus D, Keilig L, Gölz L, Stark H, Enkling N. Wear of double crown systems: electroplated vs. casted female part. J Appl Oral Sci 2013; 20:384-91. [PMID: 22858708 PMCID: PMC3881770 DOI: 10.1590/s1678-77572012000300015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 08/11/2011] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES The wear of telescopic crowns is a common problem often reducing the patient's satisfaction with the denture and resulting in a renewal of the denture. The study aims to compare the wear behavior of conical crowns using electroplated copings (group E ) with standard telescopic crowns with cast female parts (group C). MATERIAL AND METHODS 10 conical crowns were milled for each group of a cast gold alloy. The specimen of group E had a conicity of 2º. The cast secondary crowns of group C had a 0º design. The electroplated coping was established by direct electroforming. An apparatus accomplishing 10,000 wear cycles performed the wear test. The retentive forces and the correlating distance during insertion and separation were measured. The wear test was separated in a start phase, an initial wear phase and the long term wear period. The retention force value and the force-distance integral of the first 0.33 mm of each cycle were calculated. RESULTS The retentive forces were significantly higher for group E and the integrals were significantly lower for this group except the integral at cycle 10,000. The changes of retention force and integral did not differ significantly between both groups in all phases. The change of the integrals as well as the integral at the particular cycles showed higher interquartile distances for group C. CONCLUSIONS Within the limitations of this study the tested conical crowns showed clinically acceptable retentive properties. The values reached a range comparable to retentive elements tested in recent literature. The values of group C showed higher ranges. The force measured for group E was significantly higher than for group C but the integrals showed an opposite tendency. The results indicate that an exclusive analysis of the force is not sufficient as the integral is not equivalent to the force although it describes the retentive property of the system in a better way than the force over a distance is described. Both systems seem to be suitable for clinical practice.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Germany.
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Utz KH, Schneider D, Feyen J, Grüner M, Bayer S, Fimmers R, Müller F. Complete denture displacement following open-mouth reline. J Oral Rehabil 2012; 39:838-46. [DOI: 10.1111/j.1365-2842.2012.02339.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2012] [Indexed: 11/27/2022]
Affiliation(s)
- K.-H. Utz
- Department of Prosthetic Dentistry, Propaedeutics and Dental Materials; University of Bonn; Bonn
| | - D. Schneider
- Department of Prosthetic Dentistry, Propaedeutics and Dental Materials; University of Bonn; Bonn
| | - J. Feyen
- Private Practice, Lennestadt; Germany
| | - M. Grüner
- Department of Prosthetic Dentistry, Propaedeutics and Dental Materials; University of Bonn; Bonn
| | - S. Bayer
- Department of Prosthetic Dentistry, Propaedeutics and Dental Materials; University of Bonn; Bonn
| | - R. Fimmers
- Institute for Medical Biometrics, Informatics and Epidemiology (IMBIE); Bonn; Germany
| | - F. Müller
- Division of Gerodontology and Removable Prosthodontics; University of Geneva; Geneva; Switzerland
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Deslis A, Hasan I, Bourauel C, Bayer S, Stark H, Keilig L. Numerical investigations of the loading behaviour of a prefabricated non-rigid bar system. Ann Anat 2012; 194:538-44. [PMID: 22664278 DOI: 10.1016/j.aanat.2012.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 04/16/2012] [Accepted: 04/18/2012] [Indexed: 11/17/2022]
Abstract
The aim of this study has been to systematically evaluate the loading behaviour of a novel pre-fabricated chair-side SFI-Bar(®) bar system supported by two implants using finite element (FE) analysis. Two series of FE models were created of the bar placed on two idealised implants and embedded in idealised bone segments using CAD data. In the first series, the inter-implant distance varied from 10 to 26mm; the second series consisted of a bar with a fixed implant distance of 26mm and varying horizontal fitting inaccuracy from 0.0 to 0.3mm. The bar was loaded vertically at 500 N. In all simulations, the regions with the greatest amount of stress were concentrated on the connecting elements of the bar and the bar itself. A slight increase in stress was observed with decreasing inter-implant distance. With a non-zero fitting inaccuracy, no clear correlation was observed between the amount of play and the stress distribution in the system. For a perfect fit, an obvious increase in stress was found in the implant and strain in the implant bed. With respect to the excessive static loading performed in our simulations and the resulting loading behaviour, we conclude that the SFI-Bar is a system suitable for clinical application.
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Affiliation(s)
- A Deslis
- Endowed Chair of Oral Technology, Rheinische Friedrich-Wilhelms University, Welschnonnenstr. 17, 53111 Bonn, Germany
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Framme C, Wolf-Schnurrbusch U, Lobsiger H, Bayer S, Wolf S. Angepasstes und standardisiertes Patientenmanagement bei der Behandlung der neovaskulären AMD im ambulanten Bereich einer Universitäts-Augenklinik. Klin Monbl Augenheilkd 2012; 229:812-21. [DOI: 10.1055/s-0031-1299405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- C. Framme
- Universitätsklinik für Augenheilkunde, Universitätsspital, Inselspital, Bern, Schweiz
| | - U. Wolf-Schnurrbusch
- Universitätsklinik für Augenheilkunde, Universitätsspital, Inselspital, Bern, Schweiz
| | - H. Lobsiger
- Universitätsklinik für Augenheilkunde, Universitätsspital, Inselspital, Bern, Schweiz
| | - S. Bayer
- Q_Perior München, Niederlassung Schweiz
| | - S. Wolf
- Universitätsklinik für Augenheilkunde, Universitätsspital, Inselspital, Bern, Schweiz
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Bayer S, Kraus D, Keilig L, Gölz L, Stark H, Enkling N. Changes in retention force with electroplated copings on conical crowns: a comparison of gold and zirconia primary crowns. Int J Oral Maxillofac Implants 2012; 27:577-585. [PMID: 22616051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
PURPOSE The aim of this study was to examine the wear behavior of conical crowns with electroplated gold copings that are used to connect implants and teeth to a removable denture. Gold alloy and zirconium dioxide ceramic crowns were compared. MATERIALS AND METHODS Fifteen crowns each were milled for two groups: gold alloy and zirconium dioxide. Each specimen had a 2-degree taper. The electroplated coping was established by direct electroforming. The retentive forces and the correlating distance during insertion and separation were measured after 10,000 wear cycles were applied. The wear testing was separated into a start phase, an initial wear phase, and the long-term wear period. The retention force value and the force-distance integral of the first 0.3 mm of each cycle were calculated. RESULTS The changes in retention force and integral did not differ significantly between both groups in the start and the initial wear phase. No differences were seen in force development during the long-term wear period. Only the force-distance integral showed a significant difference: the median values of the gold crowns increased slightly, and they decreased slightly for the zirconia crowns. The median force values never fell below 6 N for gold and 4 N for zirconia. CONCLUSIONS Within the limitations of this study, the tested conical crowns showed clinically acceptable retentive properties. As with other retentive elements for dentures, the specimens tested showed the greatest amount of change in retentive forces during the first 2,000 cycles. The development of retention force in both groups was not significantly different. However, the zirconia specimens showed reduced variability, which is preferable in clinical practice.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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22
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Gisler V, Bassetti R, Mericske-Stern R, Bayer S, Enkling N. A cross-sectional analysis of the prevalence of dental anxiety and its relation to the oral health-related quality of life in patients with dental treatment needs at a university clinic in Switzerland. Gerodontology 2012; 29:e290-6. [PMID: 22428919 DOI: 10.1111/j.1741-2358.2011.00465.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vanessa Gisler
- Department of Prosthodontics, School of Dental Medicine, University of Bern, Bern, Switzerland
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23
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Kraus D, Deschner J, Jäger A, Wenghoefer M, Bayer S, Jepsen S, Allam JP, Novak N, Meyer R, Winter J. Human β-defensins differently affect proliferation, differentiation, and mineralization of osteoblast-like MG63 cells. J Cell Physiol 2011; 227:994-1003. [DOI: 10.1002/jcp.22808] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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24
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Vécsei-Marlovits P, Bayer S, Vécsei C, Weingessel B. Optimierung von Ambulanzabläufen am Beispiel von AMD-Untersuchungen und Behandlungen. Spektrum Augenheilkd 2011. [DOI: 10.1007/s00717-011-0047-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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25
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Bayer S, Komor N, Kramer A, Albrecht D, Mericske-Stern R, Enkling N. Retention force of plastic clips on implant bars: a randomized controlled trial. Clin Oral Implants Res 2011; 23:1377-84. [PMID: 22092547 DOI: 10.1111/j.1600-0501.2011.02312.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2011] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Retention of overdentures is important for patients' satisfaction. The study tested whether the clinical performance of retentive clips made of poly-ether-ether-ketone (PEEK) is superior to those made of poly-oxy-methylene (POM). METHODS A total of 30 patients received complete dentures with round bars (SFI-Bar) on two implants in a chairside technique. Two types of clip matrices (PEEK/POM) were used in a split-mouth technique. Retention forces were measured separately for both materials at baseline when the dentures were inserted and after 1, 3 and 6 months. The measurement was performed extraorally and intraorally by using a measuring stylus equipped, respectively, with an opposing matrix or bar part. Simultaneously, at each point in time the patient and the dentist judged the retention either to be good, or to be too high or too low. Statistical analysis involved performance of global non-parametric testing of dependence of retention force on time and material was performed with Brunner-Langer model; non-parametric 95% confidence intervals (CIs) were calculated. RESULTS At baseline the median force for POM matrices was 6.89N (95% CI: 6.50-8.21) and for PEEK matrices 7.17N (95% CI: 6.97-7.93). After 6 months, the retention of POM decreased to 5.53N (95% CI: 4.81-7.00) and of PEEK to 6.42N (95% CI: 5.15-7.51). The retention force changed significantly over time (P = 0.004) without differences between POM and PEEK (P = 0.135). No significant alteration of the retention force over time was measured at the bar (P = 0.289). Retention was estimated to be good with 90% at baseline and with 80% after 6 months, equally by patients and dentist. CONCLUSIONS POM as well as PEEK material fulfills the requirements of retentive clips on round bars.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Germany
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26
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Bayer S, Stark H, Gölz L, Keilig L, Kraus D, Hansen A, Enkling N. Telescopic crowns: extra-oral and intra-oral retention force measurement--in vitro/in vivo correlation. Gerodontology 2011; 29:e340-7. [PMID: 21453418 DOI: 10.1111/j.1741-2358.2011.00477.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study deals with the determination of the retentive forces of telescopic crowns measured extra- and intra-orally and the correlation of these values. BACKGROUND The telescopic denture is a well-documented solution for prosthetic rehabilitation for a partially edentulous jaw. Acceptable retention forces are needed to avoid inadvertent removal of the denture during movement of the jaws. Recent literature suggests 3-7 N per attachment to be acceptable. These values are only supported by in vitro studies. In vivo data are scarce, and a correlation of the in vitro and in vivo values is lacking. MATERIAL AND METHODS Twenty-five combined fixed-removable prostheses with a total of 72 double crowns were used for extra-oral retention force measurement prior to cementation (in vitro). The intra-oral measurement was performed at 72 defined measuring points of the dentures 4-6 weeks after prosthetic rehabilitation (in vivo). A specifically designed measuring device was used. RESULTS The rank correlation showed that the in vitro and in vivo values correlate with each other (Spearman's ρ = 0.5052). Additionally, it was found that the median values measured before (1.97N) insertion of the dentures were significantly lower than after (4.70N) insertion (Mann-Whitney test, p ≤ 0.0001). CONCLUSION The retention forces measured before and after insertion of the denture correlate with each other although their dimension is significantly higher after insertion. The reason for this behaviour might be some tilting during removal. Nevertheless, the correlation allows a prediction of the clinically relevant forces by a measurement of the extra-orally measured retentive values.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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27
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Bayer S, Stark H, Gölz L, Keilig L, Kraus D, Hansen A, Enkling N. Clinical retention force development of double crowns. Clin Oral Investig 2011; 16:407-11. [DOI: 10.1007/s00784-011-0530-2] [Citation(s) in RCA: 11] [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: 08/02/2010] [Accepted: 02/16/2011] [Indexed: 11/28/2022]
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Enkling N, Jöhren P, Klimberg V, Bayer S, Mericske-Stern R, Jepsen S. Effect of platform switching on peri-implant bone levels: a randomized clinical trial. Clin Oral Implants Res 2011; 22:1185-1192. [PMID: 21320171 DOI: 10.1111/j.1600-0501.2010.02090.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Norbert Enkling
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Peter Jöhren
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Victoria Klimberg
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Stefan Bayer
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Regina Mericske-Stern
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
| | - Søren Jepsen
- Department of Prosthodontics, University of Berne, Berne, SwitzerlandDepartment of Oral Surgery, University of Witten/Herdecke, Witten, GermanyDepartment of Prosthetic Dentistry, Propaedeutics and Material Science, University of Bonn, Bonn, GermanyDepartment of Periodontology, Operative and Preventive Dentistry, University of Bonn, Bonn, Germany
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Enkling N, Jöhren P, Klimberg T, Mericske-Stern R, Jervøe-Storm PM, Bayer S, Gülden N, Jepsen S. Open or submerged healing of implants with platform switching: a randomized, controlled clinical trial. J Clin Periodontol 2011; 38:374-84. [PMID: 21235615 DOI: 10.1111/j.1600-051x.2010.01683.x] [Citation(s) in RCA: 43] [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] [Indexed: 11/30/2022]
Abstract
AIM The temporal pattern of bone-level alterations in conventionally restored implants is dependent upon healing mode (open or submerged). This study examined the influence of healing on marginal bone levels at implants with a medium-rough surface including the implant collar and a clearance-fit implant-abutment connection restored according to a platform-switching concept. MATERIAL AND METHODS Two implants were placed in the posterior mandible of 21 test subjects, randomly assigned to open (OH) or submerged (SH) healing. Standardized radiographs were obtained after implant surgery, before re-entry, after crown mounting, 1 and 2 years after implant surgery, and evaluated for implant-bone-level alterations (ΔIBL). Bacterial samples of the implants' inner cavities were analysed by cultivation. STATISTICS Brunner-Langer Model, equivalence testings by Wilcoxon's (equivalence range ±0.4mm). RESULTS After 2 years, ΔIBL were -0.47±0.46mm (OH) and -0.54±0.38mm (SH). At the 1-year follow-up, all implants were contaminated with bacteria. ΔIBL (p<0.001) and the amount of bacterial contamination (p<0.001) significantly depended on time, but not on healing mode. ΔIBL of OH and SH were equivalent at all time points (all p0.044). CONCLUSIONS Platform-switched implants showed very limited peri-implant bone-level alterations. The healing-mode neither affected the total amount nor the temporal patterns of ΔIBL. Thus, the results for the tested implants with a non-rigid implant-abutment connection were similar to results reported previously for implants with a rigid implant-abutment connection.
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Affiliation(s)
- Norbert Enkling
- Department of Prosthodontics, University of Berne, Berne, Switzerland Department of Oral Surgery, University of Witten/Herdecke, Witten/Herdecke, Germany
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Enkling N, Utz KH, Bayer S, Stern RM. Osseoperception: active tactile sensibility of osseointegrated dental implants. Int J Oral Maxillofac Implants 2010; 25:1159-1167. [PMID: 21197493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023] Open
Abstract
PURPOSE The phenomenon of developing a certain tactile sensibility through osseointegrated dental implants is called osseoperception. Active tactile sensibility can be tested by having the subject bite on test bodies. The aim of the study was to describe the active tactile sensibility of single-tooth implants based on the 50% value and the slope of the sensibility curve at the 50% value. MATERIALS AND METHODS Sixty-two subjects with single-tooth implants with natural opposing teeth were included in the study. In a computer-assisted and randomized way, copper foils of varying thickness (0 to 200 Μm) were placed inter?occlusally between the single-tooth implant and the natural opposing tooth, and the active tactile perception was studied according to the psychophysical method of constant stimuli and statistically evaluated by logistic regression. RESULTS Tactile perception of the implants at the 50% value estimated by logistic regression was 20.2 ± 10.9 Μm on average, and the slope was 29 ± 15. Regarding implant surface structure, significant differences were observed. The sandblasted and acid-etched surface was significantly more sensitive than the titanium plasma-sprayed surface, and the machined surface was similar to the titanium plasma-sprayed surface. CONCLUSIONS Active tactile sensibility of implants with natural antagonistic teeth is very similar to that of teeth, but the slope of the tactile sensibility curve is flatter. Significant differences in tactile sensibility as a function of different implant surfaces may indicate that receptors near the implant form the basis of osseoperception.
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Affiliation(s)
- Norbert Enkling
- Department of Prosthodontics, University of Bern, Switzerland.
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Bayer S, Zuziak W, Kraus D, Keilig L, Stark H, Enkling N. Conical crowns with electroplated gold copings: retention force changes caused by wear and combined off-axial load. Clin Oral Implants Res 2010; 22:323-9. [PMID: 20868454 DOI: 10.1111/j.1600-0501.2010.02003.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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Abstract
OBJECTIVES Wear of attachments leads to a loss of retention and reduces the function of overdentures. This study evaluated the retention force changes of an attachment system for overdentures. The influence of the lubricant and the alloy on wear constancy was examined. METHODS Cylindrical anchors of the Dalbo(®) -Z system were tested (Cendres+Métaux SA). Three groups of alloy-lubricant combinations were generated 1.Elitor(®) /NaCl-solution (EN) 2.Elitor(®) /Glandosane(®) aquadest. (EG) and 3.Valor(®) /Glandosane(®) /aquadest. (VG). Ten samples of each group were subjected to 10 000 insertion-separation cycles. RESULTS For the EN-group, this led to a large increase in retention force. The EG- and VG-group showed a constant decrease after an initial increase in retention force at the beginning of the wear simulation. The change of the alloy caused no statistically significant differences. The use of a more viscous lubricant reduced the retention force increase significantly. CONCLUSIONS The use of a lubricant which simulates clinical conditions is an absolute need for wear simulation because the retention force changes are influenced enormously. The change of the alloy at the Dalbo(®) -Z system did not influence the wear behaviour. As a slight decrease in retention force was recorded, it is useful for an attachment system to allow compensation with an adjustable matrix.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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Bayer S, Helfgen EH, Bös C, Kraus D, Enkling N, Mues S. Prevalence of findings compatible with carotid artery calcifications on dental panoramic radiographs. Clin Oral Investig 2010; 15:563-9. [PMID: 20431901 DOI: 10.1007/s00784-010-0418-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 04/19/2010] [Indexed: 11/28/2022]
Abstract
Cerebrovascular accidents are responsible for killing or disabling more than half a million Americans every year. They are the third leading cause of death in this country. In Germany, the annual stroke incidence reaches 182 cases per 100,000 inhabitants. Stroke there is the fourth leading cause of death. There is a need of finding cost-effective means of decreasing stroke mortality and morbidity. Instruments for early diagnosis are of great humanitarian and economic importance. All possible clinical findings should be taken into account. It is not the demand of this study to present the panoramic radiograph as a screening test method for early diagnosis of atherosclerosis. The aim is to show the potential of this radiograph used in everyday clinical dental practice by the prevalence of radiopaque findings in the carotid region. This study included panoramic dental radiographs of 2,557 patients older than 30 years of age. Fifty-nine percent of the patients were women and 41% were men. The radiographs were adjudged for signs compatible with carotid arterial calcifications appearing as a radiopaque nodular mass adjacent to the cervical vertebrae at or below the intervertebral space C3-4. Of all these radiographs, 4.8% showed radiopaque findings compatible with atherosclerotic lesions. The proportion of women reached 64.8% and that of men reached 35.2%. In accordance to recent literature, the results of this study show that about 5% of the patients show radiological findings compatible with carotid arterial calcifications. Some of these patients at risk for a cerebrovascular accident may be identified in the dentist's office by appropriate review of the panoramic dental radiograph. The suspicion of carotid artery calcifications demands an impetuous referral to an appropriate practitioner who can assist in the control of risk factors and if necessary arrange surgical removal of the carotid arterial plaque. So, the dentist should be aware of this problem and able to make a contribution to stroke prevention.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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Enkling N, Heussner S, Nicolay C, Bayer S, Mericske-Stern R, Utz KH. Tactile Sensibility of Single-Tooth Implants and Natural Teeth Under Local Anesthesia of the Natural Antagonistic Teeth. Clin Implant Dent Relat Res 2009; 14:273-80. [DOI: 10.1111/j.1708-8208.2009.00252.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Khan E, Bayer S, Kempe R, Wrackmeyer B. Synthesis and Molecular Structure of Silole Derivatives Bearing Functional Groups on Silicon: 1,1‐Organoboration of Dialkynylsilanes. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200900697] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ezzat Khan
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany, Fax: +49‐921‐552157
- Department of Chemistry, University of Malakand, Chakdara, Dir (Lower), North West Frontier Province, Pakistan
| | - Stefan Bayer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany, Fax: +49‐921‐552157
| | - Rhett Kempe
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany, Fax: +49‐921‐552157
| | - Bernd Wrackmeyer
- Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany, Fax: +49‐921‐552157
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Enkling N, Nicolay C, Bayer S, Mericske-Stern R, Utz KH. Investigating interocclusal perception in tactile teeth sensibility using symmetric and asymmetric analysis. Clin Oral Investig 2009; 14:683-90. [DOI: 10.1007/s00784-009-0348-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Accepted: 09/24/2009] [Indexed: 11/24/2022]
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Enkling N, Bayer S, Jöhren P, Mericske-Stern R. Vinylsiloxanether: A New Impression Material. Clinical Study of Implant Impressions with Vinylsiloxanether versus Polyether Materials. Clin Implant Dent Relat Res 2009; 14:144-51. [DOI: 10.1111/j.1708-8208.2009.00240.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bayer S, Ballschmiter M, Greiner-Stoeffele T. Identification of a new lipolytic enzyme family and several novel nitrilases in metagenomic libraries. N Biotechnol 2009. [DOI: 10.1016/j.nbt.2009.06.317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bayer S, Steinheuser D, Grüner M, Keilig L, Enkling N, Stark H, Mues S. Comparative study of four retentive anchor systems for implant supported overdentures--retention force changes. Gerodontology 2009; 26:268-72. [PMID: 19371390 DOI: 10.1111/j.1741-2358.2009.00286.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Wear of attachments leads to a loss of retention and potentially reduces the function of complete dentures. This study evaluated the retention force changes of different prefabricated attachment systems for implant-supported overdentures to estimate the wear constancy and applicability in clinical practice. METHODS Four prefabricated attachment systems were tested [Group SG: retentive ball attachment (Straumann, Switzerland) with gold matrix, Group ST: retentive ball attachment (Straumann, Switzerland) with titanium spring matrix, Group IB: UNOR i-Ball with Ecco matrix (UNOR, Switzerland) and Group IMZ: IMZ-TwinPlus ball attachment with gold matrix (DENTSPLY Friadent, Germany)]. Ten samples of each system were subjected to 10,000 insertion-separation cycles. RESULTS Results showed that all types of attachments showed wear, which led to a loss of retention force after an initial increase at the beginning of the wear simulation. Attachments with a plastic retention insert or gold matrices underwent the smallest changes in retention force. The titanium spring system showed the largest changes in retention force and a greater variation between the different cycles and specimen. This behaviour is probably caused by a large fitting tolerance of the titanium spring. CONCLUSIONS Attachment systems which possess a male and female component of different material composition are preferable. They show smaller changes in the retention force. For retention force increase and wear compensation, an attachment system should be adjustable.
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Affiliation(s)
- Stefan Bayer
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, University of Bonn, Bonn, Germany.
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Keilig L, Stark H, Bayer S, Utz KH, Strazza M, Grüner M, Bourauel C. Numerical investigation of the mechanical loading of supporting soft tissue for partial dentures. INT J PROSTHODONT 2009; 22:201-203. [PMID: 19418869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aim of this research was to study the impact of loading on partial dentures within the supporting soft tissue with respect to different attachment techniques. A finite element model was developed to calculate the stress and strain distribution in this tissue. The model consisted of the left half of a mandible with three remaining teeth that had suffered an atrophy in the anterior region, and a partial denture over the toothless area that was connected at the left mandibular canine using an attachment system. Resulting stress/strain distributions are presented for different load cases using a commercially available prefabricated attachment system.
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Affiliation(s)
- Ludger Keilig
- Endowed Chair of Oral Technologies, Dental School, University of Bonn, Bonn, Germany.
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Bayer S, Grüner M, Keilig L, Hültenschmidt R, Nicolay C, Bourauel C, Utz KH, Stark H. Investigation of the wear of prefabricated attachments--an in vitro study of retention forces and fitting tolerances. Quintessence Int 2007; 38:e229-37. [PMID: 17568826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
OBJECTIVE To quantify wear processes by measuring the retention force changes and the fitting tolerance at different prefabricated attachment systems to estimate the wear constancy and applicability in clinical practice. METHOD AND MATERIALS Seven prefabricated attachment systems (Dalbo-Classic, Dalbo-PLUS, Dalbo-Z, Mini-Gerber-PLUS, Stufenexzenter, SpharoLock, and Degussa-Kugelankersystem) with different construction and alloy composition were tested. Twenty samples of each system were subjected to 10,000 insertion-separation cycles in a wear simulator with a periodontium-simulating specimen holder. The simulator was designed to record the force needed to insert and to separate the attachment and the distance moved during the insertion and separation cycles. RESULTS All types of anchors showed wear that led to a loss or to an increase in retention force at the beginning of the wear simulation. Anchors with a plastic retention insert showed the slightest changes in retention force. The wear does not have an effect on the fitting tolerance. CONCLUSION Anchor systems that possess an adjustable matrix should be preferred. They allow decreasing or increasing the retention force of an anchor if this force is changed by wear. There is no risk of a loss of support if forces in occlusal direction are exerted because there is no clinically relevant change in the fitting tolerance.
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Affiliation(s)
- Stefan Bayer
- Department of Preclinical Education and Experiemtntal Research, University of Bonn, Germany.
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Pettitt M, Burnett G, Bayer S, Stevens A. Assessment of the occlusion technique as a means for evaluating the distraction potential of driver support systems. ACTA ACUST UNITED AC 2006. [DOI: 10.1049/ip-its:20060027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Méry J, Bayer S. Comparison of external costs between dry tomb and bioreactor landfills: taking intergenerational effects seriously. Waste Manag Res 2005; 23:514-26. [PMID: 16379120 DOI: 10.1177/0734242x05060857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Dry tomb and bioreactor landfills were analyzed with respect to their external costs in an intergenerational cost-benefit analysis in a partial framework which enabled a sounder comparison to be carried out between these two technologies from a socio-economic viewpoint. Obviously, this approach was only a first step for building a comprehensive basis of any environmental as well as fiscal policy in the field of waste management. All external costs are identified and evaluated in three different scenarios, corresponding to a worst case, a best guess and a best case. Obviously, discounting is crucial with respect to an intergenerational perspective. Generation-adjusted discounting (GAD) was applied to take into account equity as well as efficiency criteria, in order to deal with three different types of uncertainties that are decisive in waste policy decisions: a physical uncertainty is captured by introducing our three different scenarios; a macroeconomic uncertainty is taken into consideration by calculating present values using different real growth rates; and a microeconomic uncertainty is taken into account by considering individual peculiarities reflected in their subjective time preference rate. The findings show, that whenever there is a low real GDP growth of less than 1%, the bioreactor is generally superior to the dry tomb (lower present values of external costs). This statement becomes more valid as the growth rate decreases. However, whenever there are high positive growth rates, it is the dry tomb technology which is superior to the bioreactor system.
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Affiliation(s)
- Jacques Méry
- Hydrosystems and Bioprocesses Research Unit, French Institute of Agricultural and Environmental Engineering Research (Cemagref), Antony, France.
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Voigt M, Bayer S, Dudenhausen JW. Veränderung der somatischen Klassifikation Neugeborener nach Schwangerschaftsdauer und Geburtsgewicht durch den täglichen Zigarettenkonsum der Mütter in der Schwangerschaft. Z Geburtshilfe Neonatol 2004. [DOI: 10.1055/s-2003-818288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Keilig L, Bourauel C, Grüner M, Hültenschmidt R, Bayer S, Utz KH, Stark H. Aufbau und Erprobung eines neuartigen Meßsystems für die dentale Biomechanik – Meßprinzip und Beispielmessungen des Hexapod-Meß-Systems / Design and Testing of a Novel Measuring Set-up for Use in Dental Biomechanics – Measuring Principle and Exemplary Measurements with the Hexapod Measuring System. BIOMED ENG-BIOMED TE 2004; 49:208-15. [PMID: 15481409 DOI: 10.1515/bmt.2004.039] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [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: 11/15/2022]
Abstract
A novel measuring set-up based on a hexapod system for use in dental biomechanics is described. It was specially developed to measure force/deflection characteristics of different dental materials and devices. The functionability and suitability of the system for use in experimental biomechanics were investigated in two different studies. In a first study the micro mobility of prosthetic telescopic crowns prior to and after simulated wear was determined to investigate the influence of wear processes on the stability of the anchorage elements and thus of prostheses. This study investigated the ability of the setup to load a specimen with high forces or torques of up to 100 Newton. The second study looked at the force/deflection characteristics of orthodontic anchorage pins used in orthodontics to additionally stabilize the anchorage unit, for example during molar movement. In this study specimens were loaded with small forces of less than 10 Newton, as are typically used in orthodontics. Using the setup, the deflection behaviour of these devices under high and low loading was measured at a resolution of approximately one micrometer or one angular second.
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Affiliation(s)
- L Keilig
- Abteilung für Zahnärztliche Propädeutik--Experimentelle Zahnheilkunde der Rheinischen Friedrich-Wilhelms-Universität Bonn.
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Abstract
GABAergic regulation of intestinal motility through the modulation of non-adrenergic non-cholinergic (NANC) neurons remains poorly understood especially in rat colon where very few studies have been undertaken. Therefore, the effects of GABA on circular preparations of rat distal colon were investigated using classical organ bath chambers to record spontaneous mechanical activities (SMA). SMA was characterized by the occurrence of rhythmic phasic contractions (type-I) or by spontaneously occurring large contractions superimposed on small rhythmic contractions (type-II). In the presence of atropine and guanethidine (NANC conditions), these large contractions were inhibited by bicuculline, a GABA(A)-receptor antagonist as well as by TTX, L-NAME and apamin together, or L 732-138, a NK1-receptor antagonist. In NANC conditions, GABA induced a transient monophasic relaxation or a biphasic effect characterized by a relaxation followed by a tonic contraction in both type-I and -II preparations. Both the inhibitory and excitatory effects of GABA were blocked by TTX and L-NAME + apamin; the GABA-induced contraction was also sensitive to L 732-138. The responses to GABA were mimicked by the GABA(A)-receptor agonist, muscimol, whereas baclofen and CACA, respectively GABA(B) and GABA(C)-receptors agonists showed no effect. These results demonstrated that only GABA(A)-receptors seem to be involved in the regulation of SMA in rat distal colon in NANC conditions. Release of NANC inhibitory transmitter (NO and probably ATP) and NANC excitatory transmitter (maybe substance P) might be involved.
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Affiliation(s)
- S Bayer
- INSERM Unité 338. Groupe de Neurogastroentérologie. Pavillon Poincaré. Hôpital Civil. 67000 Strasbourg, France
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Kehm E, Göksu M, Bayer S, Knopf CW. Herpes simplex virus type 1 DNase: functional analysis of the enzyme expressed by recombinant baculovirus. Intervirology 2000; 41:110-9. [PMID: 9820845 DOI: 10.1159/000024922] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [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: 11/19/2022] Open
Abstract
Herpes simplex virus type 1 DNase (HSV-1 DNase) was expressed in insect cells by recombinant baculovirus (NPVUL12) and purified by a combination of anionic exchanger chromatography and gel filtration. Two polypeptides of 85 and 75 kD, whose ratio varied during purification, were induced 24 h after infection. The 75-kD protein was isolated and shown to possess catalytic activity. Gel filtration analysis indicated that the active form of the enzyme at an ionic strength of I = 0.3 is a dimeric protein with an apparent molecular weight of 130,000. The recombinant enzyme exhibited the overall characteristics of the native enzyme such as 5'-3' exonuclease and endonuclease activities with a preferred degradation of DNA. In the absence of extraneously added Mg2+, the enzyme was capable of removing mononucleotides from 5'-end-labeled DNA, but not from RNA and 3'-end-labeled DNA. The peculiar mechanism of double-strand DNA degradation suggests a specific role of HSV-1 DNase in DNA recombination processes during viral replication.
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Affiliation(s)
- E Kehm
- Deutsches Krebsforschungszentrum, Genomforschung und Bioinformatik, Heidelberg, Deutschland
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Ward N, Bayer S, Ballard M, Patience T, Hume RF, Calhoun BC. Impact of prenatal care with reduced frequency of visits in a residency teaching program. J Reprod Med 1999; 44:849-52. [PMID: 10554744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
OBJECTIVE To determine if decreasing the number of prenatal visits for routine obstetric patients affects pregnancy outcome. STUDY DESIGN A historical control study was designed to include 734 deliveries from January 1 to December 31, 1991, in women who had prenatal care per American College of Obstetricians and Gynecologists Committee Opinion no. 79, January 1990, guidelines for uncomplicated obstetric care. A prospective study cohort of women with 711 deliveries from January 1 to December 31, 1994, underwent prenatal care with modified guidelines to include: first visit at 6-12 weeks to confirm dating and obtain initial laboratory data, second visit at 16-20 weeks to obtain maternal serum alpha-fetoprotein screening, third visit at 24-28 weeks for 28-week laboratory data, fourth visit at 32 weeks, fifth visit at 36 weeks, sixth visit at 38 weeks, seventh visit at 40 weeks and weekly thereafter. Pregnancy outcomes included estimated fetal weight, gestational age at delivery, preeclampsia, Apgar score at one and five minutes and delivery mode. Neonatal outcomes, including stillbirth rate, preterm delivery rate, intraventricular hemorrhage rate, bronchopulmonary dysplasia and neonatal mortality, were evaluated. RESULTS There were no statistically significant differences in perinatal or neonatal outcomes with decreased prenatal visits from an average of 12 per pregnancy to 8. CONCLUSION Prenatal visits can be decreased in a teaching hospital in women with uncomplicated pregnancies from the standard number, 12-14 visits, to an average of 7 or 8 per patient without adverse perinatal outcomes.
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Affiliation(s)
- N Ward
- Department of Obstetrics and Gynecology, Madigan Army Medical Center, Tacoma, Washington 98341, USA
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