Claudia Reicheneder

Publications of Claudia Reicheneder

• Effect of excessive methionine on the development of the cranial growth plate in newborn rats.

  Authors: Piero Römer, Jens Weingärtner, Benjamin Desaga, Dietmar Kubein-Meesenburg, Claudia Reicheneder, Peter Proff

  Archives of oral biology. 03/2012;

  OBJECTIVE: Methionine is an essential amino acid and pivotal for normal growth and development. However, previous animal studies have shown that excessive maternal intake of methionine causes growthOBJECTIVE: Methionine is an essential amino acid and pivotal for normal growth and development. However, previous animal studies have shown that excessive maternal intake of methionine causes growth restrictions, organ damages, and abnormal growth of the mandible in newborn animals. However, the effect of excessive methionine on the development of the cranial growth plate is unknown. This study investigated histological alterations of the cranial growth plate induced by high methionine administration in newborn rats. DESIGN: Twenty pregnant dams were divided into a control and an experimental group. The controls received a diet for rats and the experimental group was fed from the 18th gestational day with a special manufactured high methionine diet for rats. The high methionine diet was maintained until the end of the lactation phase (day 20). The offspring of both groups were killed at day 10 or 20 postnatally and their spheno-occipital synchondroses were collected for histological analysis. RESULTS: The weight of the high-dose methionine treated experimental group was considerably reduced in comparison to the control group at day 10 and 20 postnatally. The cartilaginous area of the growth plate and the height of the proliferative zone were markedly reduced at postnatal day 10 in the experimental group. CONCLUSIONS: In summary, the diet-induced hypermethioninemia in rat dams resulted in growth retardations and histomorphological changes of the spheno-occipital synchondrosis, an important craniofacial growth centre in newborns. This finding may elucidate facial dysmorphoses reported in patients suffering from hypermethioninemia.

• An Investigation about the Influence of Bleaching on Shear Bond Strength of Orthodontic Brackets and on Enamel Colour.

  Authors: Isabell Immerz, Peter Proff, Piero Roemer, Claudia Reicheneder, Andreas Faltermeier

  ISRN dentistry. 01/2012; 2012:375849.

  The aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. TheThe aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. The bleaching and bonding techniques were performed on extracted bovine teeth for the investigation of their colorimetric spectrum and the adhesive bond strength on surface enamel. One group was designated as the control group with no pre-treatment. Another group was treated with a 45% hydrogen peroxide solution prior to bonding. The difference in colour was expressed as the Euclidian distance ΔE. The resulting shear bond strength was analyzed and evaluated by scores of Adhesion Remnant Index. Statistical analysis was performed using the Kruskall-Wallis and post-hoc test. The colorimetric analysis revealed statistically significant differences between original and bleached as well as bleached and debonded teeth setting off a blue colour shift. Furthermore, statistically there was no significant difference noted in bonding strength between non-treated surfaces and those treated with peroxide. It can be concluded that peroxide pre-treatment does result in colour differences of teeth. Bonding and debonding procedures seem to have no statistically significant influence on the enamel colour using current materials.

• Effects of hypodontia on craniofacial structures and mandibular growth pattern.

  Authors: Amelia Kreczi, Peter Proff, Claudia Reicheneder, Andreas Faltermeier

  Head & face medicine. 12/2011; 7:23.

  This study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandibleThis study was performed to examine craniofacial structures in persons with hypodontia and to reveal any differences, that may occur, when agenetic teeth are only found in the maxilla, the mandible or in both jaws. The groups consistent of 50 children (33 girls, 17 boys) aged between 9 and 13.5 years were analyzed and assigned to three subgroups. Group 1 = upper jaw hypodontia. Group 2 = lower jaw hypodontia. Group 3 = hypodontia in both jaws. Eleven angular and three index measurements from lateral encephalographs and two linear measurements from dental blaster casts were calculated. All data was statistically analyzed, parameters with p < 5% were investigated for each subgroup respectively. In comparison with standards the study group showed bimaxillary retrognathism and a reduction of the lower anterior facial height. Moreover both overbite and overjet significantly increased. Other values laid within the normal ranges. Evaluating results of the subgroups, differences in the means of SNA, SNB and overjet between the groups were observed.Analysis of the mandibular growth pattern revealed, that neither vertical nor horizontal patterns are dominant in hypodontia patients. In certain dentofacial parameters differences between persons with hypodontia and such with full dentition exist. According to our findings agenetic teeth may have a negative influence on the saggital development of a jaw and the lower face and may be responsible for increased overbites. This should receive attention in orthodontic treatment of hypodontia patients.

• Controlled central advancement of the midface after Le Fort III osteotomy by a 3-point skeletal anchorage.

  Authors: J Camilo Roldán, Antonios Moralis, Sebastian Dendorfer, Jens Witte, Claudia Reicheneder

  The Journal of craniofacial surgery. 11/2011; 22(6):2384-6.

  A 3-point skeletal anchorage with taping screws for distraction osteogenesis after a Le Fort III osteotomy was applied for the first time in a severely mentally impaired patient where intraoralA 3-point skeletal anchorage with taping screws for distraction osteogenesis after a Le Fort III osteotomy was applied for the first time in a severely mentally impaired patient where intraoral devices had to be avoided. All 3-force application points included the center of resistance, which allowed an optimal control on the resulting moment. A novel device for skeletal long-term retention into the nasal dorsum prevented a relapse, whereas adjustment of the midface position was observed. Fusioned three-dimensional computed tomography analysis revealed real movements not accessible by a conventional cephalometry.

• Strontium promotes cell proliferation and suppresses IL-6 expression in human PDL cells.

  Authors: Piero Römer, Benjamin Desaga, Peter Proff, Andreas Faltermeier, Claudia Reicheneder

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 10/2011;

  This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells.This study was designed to investigate the effect of strontium on human PDL cells in vitro. Strontium is used to treat osteoporosis because of its bone formation promoting effect on osteoblast cells. This investigation presents evidence that strontium promotes PDL cell proliferation. Simultaneously, strontium suppresses the expression of the inflammation-promoting cytokine IL-6. The observed effect of strontium on PDL cells supports its use it in guided dental tissue regeneration.

• The influence of electron beam irradiation on colour stability and hardness of aesthetic brackets.

  Authors: Julia Faltermeier, Philipp Simon, Claudia Reicheneder, Peter Proff, Andreas Faltermeier

  European journal of orthodontics. 04/2011;

  Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100Electron beam irradiation can be used to improve the mechanical properties of polymers. The aim of this study was to investigate the influence of electron beam irradiation with an energy dose of 100 kGy on the mechanical properties and colour stability of conventional polymer brackets and experimental filled composite brackets. The conventional brackets tested were Aesthetik-Line, Brillant, and Envision. The experimental brackets contained urethane dimethacrylate, as a monomer matrix and functional silane-treated SiO(2) fillers with a filler content of either 10 (Exper 1) or 40 (Exper 2) vol per cent. The influence of electron beam post-curing on Vickers hardness (VH) of the polymer brackets was investigated. Additionally, a possible discolouration of the brackets after electron beam irradiation was determined according to the three-dimensional L* a* b* colour space. The irradiated brackets were compared with untreated control groups. Statistical analysis was performed using the Wilcoxon test. With the exception of Brillant brackets, all investigated brackets showed a significant enhancement of VH after electron beam post-curing. However, the brackets suffered a significant increase in discolouration. Aesthetik-Line brackets showed the highest discolouration, ΔE, and Exper 2 brackets the lowest ΔE values. The discolouration of the examined brackets differed significantly. These results demonstrate that the mechanical properties of polymer brackets could be modified by electron beam irradiation. Nevertheless, clinical use of electron beam post-curing might be restricted because of unacceptable colour changes.

• Effect of strontium on human Runx2+/- osteoblasts from a patient with cleidocranial dysplasia.

  Authors: Piero Römer, Michael Behr, Peter Proff, Andreas Faltermeier, Claudia Reicheneder

  European journal of pharmacology. 03/2011; 654(3):195-9.

  Strontium represents a new generation of anti-osteoporotic agents that exert anti-catabolic and anabolic effects on bone cells at once. We used strontium in vitro in order to examine its potential toStrontium represents a new generation of anti-osteoporotic agents that exert anti-catabolic and anabolic effects on bone cells at once. We used strontium in vitro in order to examine its potential to stimulate bone marker transcription and hydroxyapatite formation on isolated Runx2(+/-) osteoblasts from a patient with cleidocranial dysplasia. This disease is evoked by heterozygous mutations of Runx2, an important transcription factor for osteoblast maturing and transcription of osteogenic genes, which results in insufficient gene dosage of Runx2. This genetic defect is responsible, for example, for patent fontanels, sometimes throughout the life, supernumerary teeth, and aplasia or hypoplasia of clavicles and mimics symptoms of hypophosphatasia. In this trial, we investigated the effect of strontium on gene expression of bone marker proteins, the formation of hydroxyapatite and the cell proliferation of strontium-treated Runx2(+/-)-osteoblasts. Unlike normal osteoblasts, gene expression of bone marker proteins was not affected in strontium-treated Runx2(+/-) osteoblasts, while improved hydroxyapatite formation was noted in the extracellular matrix. A WST-1 cell proliferation assay with strontium-treated Runx2(+/-)-osteoblasts showed that strontium induces cell proliferation and growth. This effect might be responsible for the improved mineralisation of the extracellular matrix of strontium-treated Runx2(+/-)-osteoblasts observed.

• Electron-beam irradiation of polymer bracket materials.

  Authors: Andreas Faltermeier, Michael Behr, Claudia Reicheneder, Peter Proff, Piero Römer

  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 01/2011; 139(1):e7-e11.

  Electron-beam irradiation can be used to influence the properties of polymers. Electron beams cause cross-linking that enhances the molecular mass of the polymer; this leads to branched chains until,Electron-beam irradiation can be used to influence the properties of polymers. Electron beams cause cross-linking that enhances the molecular mass of the polymer; this leads to branched chains until, ultimately, a 3-dimensional network is formed. The aim of this study was to evaluate the effect of electron-beam irradiation on polymer bracket materials. Since polymers are commonly used materials for brackets, polyoxymethylene, polycarbonate, and polyurethane were chosen for this study. The acceleration voltage of the electron-beam device was 10 MeV, and the energy dose was 100 kGy with an electron accelerator (BGS beta gamma service, Rhodotron, Bruchsal, Germany). Three-medium wear, fracture toughness, and Vickers hardness tests were performed. The irradiated samples were compared with untreated control groups. Polycarbonate and polyurethane bracket materials have enhanced fracture toughness and Vickers hardness after electron-beam irradiation of 100 kGy and 10 MeV. Polyoxymethylene bracket materials showed significantly lower fracture toughness values after irradiation compared with the untreated control group. Polyoxymethylene had the best mechanical properties, followed by polycarbonate and polyurethane. Almost the same effects could be measured during the 3-medium wear test. Electron-beam postcuring improved Vickers hardness and fracture toughness of polymers with lower mechanical properties (polycarbonate and polyurethane). Polyoxymethylene, with sufficient hardness and fracture toughness, could not be improved with electron-beam postcuring.

• Development dependent collagen gene expression in the rat cranial base growth plate.

  Authors: Piero Römer, Jens Weingärtner, J Camilo Roldán, Peter Proff, Claudia Reicheneder

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 08/2010; 192(4):205-9.

  The spheno-occipital synchondrosis is part of the cranial base growth plate and is of crucial importance in craniofacial development. In this investigation, we studied changes in collagen geneThe spheno-occipital synchondrosis is part of the cranial base growth plate and is of crucial importance in craniofacial development. In this investigation, we studied changes in collagen gene expression in the spheno-occipital synchondrosis in order to identify the developmental stages most important for extracellular matrix production and ossification of the rat cranial base growth plate. Gene transcripts of type II and X collagen were most abundant at day 10 postnatally in the spheno-occipital synchondrosis. This observation is assumed to be due to intrinsic genetic factors and local environmental factors.

• Variations in the inclination of the condylar path in children and adults.

  Authors: Claudia Reicheneder, Tomas Gedrange, Uwe Baumert, Andreas Faltermeier, Peter Proff

  The Angle orthodontist. 10/2009; 79(5):958-63.

  Objective: To test the null hypothesis that there are no differences between children and adults in the condylar path inclination angle on the right and left sides. Materials and Methods: A group ofObjective: To test the null hypothesis that there are no differences between children and adults in the condylar path inclination angle on the right and left sides. Materials and Methods: A group of 80 children aged 6 to 10 years (subgroups I through V, according to chronologic age) was compared with an adult group with regard to the condylar path inclination angle (CPIA) on the right and left sides. The CPIA was measured using the ultrasonic JMA-System for registration. Results: During development of the temporomandibular joint the condylar path inclination angle increased with age in the subgroups of children. A significant difference was found in the CPIA between the groups of adults and children. In the group with the oldest children (mean age: 10.3 years) the condylar path inclination angle had reached 81.87% on the right side and 78.85% on the left side compared with the adult group at a 5 mm protrusive path. In the pooled group of children the CPIA amounted to 73.08% on the right side and 72.13% on the left side compared with the values for the adults. No significant difference was found between the right and left CPIA in any group. Conclusion: The hypothesis is rejected. The CPIA on the right and left sides increased with age in the group of children and was significantly smaller in the group of children compared with the group of adults.

• The influence of the root cross-section on the stress distribution in teeth restored with a positive-locking post and core design: a finite element study.

  Authors: Kai-Uwe Schilling, Kurt Rottner, Julian Boldt, Peter Proff, Tomasz Gredes, Ernst-Jürgen Richter, Claudia Reicheneder

  Biomedizinische Technik. Biomedical engineering. 10/2008;

  Abstract Human teeth with substantial coronal defects are subject to reconstruction by means of post and core restorations. Typically, such a restoration comprises a slightly cylindrical post ontoAbstract Human teeth with substantial coronal defects are subject to reconstruction by means of post and core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, we proposed a new proprietary post and core design which makes use of positive locking. As this prefabricated system is not customised to an individual root's cross-sectional geometry (usually oval), a varying amount of radicular dentin is left in periphery of the core's outer edge. The aim of this study was to assess the implications of this fact, i.e., whether the root has to endure higher overall stress levels which ultimately may lead to failure of one of the components involved. A series of finite element simulations were performed to evaluate stress and strain on the system, in which the proposed post and core was embedded into a virtual dentin cylinder of different diameters, ranging from flush mounting of the restoration to a dentin excess of 4 mm, and subsequently loaded with forces with two angles of attack (90 degrees and 130 degrees ). The results show that flush mounting yields an agreeable stress and strain distribution within the radicular dentin, but overall stress levels drop significantly with an excess of 0.5 mm of surrounding dentin. More than 1 mm excess was not found to have profound positive effects.

• Comparison of maximum mouth-opening capacity and condylar path length in adults and children during the growth period.

  Authors: Claudia Reicheneder, Peter Proff, Uwe Baumert, Tomas Gedrange

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 06/2008;

  A group of 80 children ranging in age from 6 to 10 years (subdivided into groups 1-5 according to chronological age) has been compared with an adult group on the basis of condylar path length andA group of 80 children ranging in age from 6 to 10 years (subdivided into groups 1-5 according to chronological age) has been compared with an adult group on the basis of condylar path length and maximum mouth-opening capacity. The condylar path length and the mouth-opening capacity were measured using the ultrasonic JMA((R))-System for registration. In the development of the temporomandibular joint (TMJ), condylar path length and mouth-opening capacity were found to increase with age in the juvenile group. In the oldest juvenile subgroup (subgroup 5; average age: 10.3 years) the condylar path length reached 17.6mm on the left and 17.3mm on the right. This is equivalent to 90.3% (left) and 91.1% (right) of the size in the adult group. The mean maximum mouth-opening capacity of the oldest juvenile subgroup was 56.3mm and reached 98.9% of the size in the adult group.

• Discolouration of orthodontic adhesives caused by food dyes and ultraviolet light.

  Authors: Andreas Faltermeier, Martin Rosentritt, Claudia Reicheneder, Michael Behr

  European journal of orthodontics. 03/2008; 30(1):89-93.

  Enamel discolouration after debonding of orthodontic attachments could occur because of irreversible penetration of resin tags into the enamel structure. Adhesives could discolour because of foodEnamel discolouration after debonding of orthodontic attachments could occur because of irreversible penetration of resin tags into the enamel structure. Adhesives could discolour because of food dyes or ultraviolet irradiation. The aim of this study was to investigate the colour stability of adhesives during ultraviolet irradiation and exposure to food colourants. Four different adhesives were exposed in a Suntest CPS+ ageing device to a xenon lamp to simulate natural daylight (Transbond XT, Enlight, RelyX Unicem, and Meron Plus AC). Tomato ketchup, Coca Cola, and tea were chosen as the food colourants. After 72 hours of exposure, colour measurements were performed by means of a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system and colour changes (DeltaE*) were computed. Statistical differences were investigated using two-way analysis of variance (ANOVA) and Friedman test. Unsatisfactory colour stability after in vitro exposure to food colourants and ultraviolet light was observed for the conventional adhesive systems, Transbond XT and Enlight. RelyX Unicem showed the least colour change and the resin-reinforced glass-ionomer cement (GIC), Meron Plus AC, the greatest colour change. The investigated adhesives seem to be susceptible to both internal and external discolouration. These in vitro findings indicate that the tested conventional adhesive systems reveal unsatisfactory colour stability which should be improved to avoid enamel discolouration.

• Mechanical loading of orthodontic miniscrews - significance and problems: an experimental study.

  Authors: Claudia Reicheneder, Kurt Rottner, Ivan Bokan, Ronald Mai, Günter Lauer, Gerd Richter, Tomasz Gedrange, Peter Proff

  Biomedizinische Technik. Biomedical engineering. 02/2008; 53(5):242-5.

  Abstract Orthodontic miniscrews are exposed to three mechanical loading phases during clinical use: torsional loading upon insertion, flexural loading during anchorage function, and torsional loadingAbstract Orthodontic miniscrews are exposed to three mechanical loading phases during clinical use: torsional loading upon insertion, flexural loading during anchorage function, and torsional loading upon removal. The aim of this study was to simulate clinical loading conditions for different types of orthodontic miniscrews in vitro to quantify the effects of combined torsional and bending stress. Various orthodontic miniscrew systems (Lomas, Dual-top, Aarhus anchorage, Tomas-pin and T.I.T.A.N.-pin) comprising 10 samples each were subjected to the following loading sequences in vitro: a torsional load corresponding to manual insertion with limited torque; and flexural loading at two different insertion depths. For all screw systems with torsional pre-loading (simulating insertion), subsequent flexural loading (simulating anchorage) yielded permanent deformations of approximately 0.15-0.25 mm, depending on the insertion depth. Since EDX analysis revealed comparable elemental compositions for the different screw systems, the differences in mechanical properties are attributed to screw design. Torsional loading during screw insertion may cause premature mechanical weakening and needs to be minimized. Unless fully inserted, screws show pronounced plastic deformation and hence fracture risk under subsequent flexural loading.

• Effect of load angulation and crown shape on forces acting on post and core restored teeth: an in vitro study.

  Authors: Kurt Rottner, Claudia Reicheneder, Julian Boldt, Peter Proff, Jens Weingaertner, Ernst-Jürgen Richter

  Biomedizinische Technik. Biomedical engineering. 02/2008; 53(5):246-50.

  Abstract To assess the usefulness of different post and core materials and systems, in vitro testing of fracture strength and fatigue resistance is a useful tool. However, the literature does notAbstract To assess the usefulness of different post and core materials and systems, in vitro testing of fracture strength and fatigue resistance is a useful tool. However, the literature does not present coherent results as to which system can withstand the highest loads. With a geometrical model, the effects of load angulation and contact point location on the generated forces were calculated. To validate the mathematical model, a set of measurements was performed with a set-up that made it possible to measure the critical forces on a post and core restoration. A high level of correlation between the predictions of the model and the measurements was found. It was shown that the resulting forces are strongly dependent on the precise design of the test set-up and results from different geometries cannot be compared directly. Very strong sensitivity to small misalignment was found, all of which serves to explain the large differences in the literature.

• An in vitro comparative assessment of different enamel contaminants during bracket bonding.

  Authors: Andreas Faltermeier, Michael Behr, Martin Rosentritt, Claudia Reicheneder, Dieter Müssig

  European journal of orthodontics. 01/2008; 29(6):559-63.

  In orthodontics, adhesive failures can occur because of saliva contamination during bonding. However, most in vitro studies concerning bond strength of saliva-contaminated enamel disregard theIn orthodontics, adhesive failures can occur because of saliva contamination during bonding. However, most in vitro studies concerning bond strength of saliva-contaminated enamel disregard the influence of temperature changes in a wet environment. The aim of the present study was to compare the influence of saliva, blood and etching gel remnant contamination on shear bond strength (SBS) after thermocycling. After etching of extracted human third molars (n = 80), a conventional primer (Transbond XT) and a moisture-insensitive primer (Transbond MIP) were evaluated using the adhesive, Transbond XT, under dry conditions and after contamination with saliva, blood and etching gel remnants. To simulate temperature changes and the moisture of saliva in the oral cavity, all samples were thermocycled (6,000 x 5 degrees C/55 degrees C) in a mastication device before SBS testing. A Mann-Whitney U test was used to determine statistical differences. Under dry conditions Transbond XT and Transbond MIP showed no significant difference in SBS. However, clinically unacceptable (P = 0.005) bond strength was observed using Transbond XT after saliva and blood contamination. In wet conditions only Transbond MIP showed sufficient bond strength. If contamination during bonding is expected, a hydrophilic primer should be used. Under dry conditions hydrophilic or hydrophobic primers could be applied. Blood contamination seems to be a more serious problem for bond strength than saliva or etching gel contamination.

• Influence of filler level on the bond strength of orthodontic adhesives.

  Authors: Andreas Faltermeier, Martin Rosentritt, Rupert Faltermeier, Claudia Reicheneder, Dieter Müssig

  The Angle orthodontist. 06/2007; 77(3):494-8.

  OBJECTIVe: To evaluate the effect of different filler contents of orthodontic adhesives on shear bond strength and Adhesive Remnant Index (ARI). MATERIALS AND METHODS: Four experimental adhesiveOBJECTIVe: To evaluate the effect of different filler contents of orthodontic adhesives on shear bond strength and Adhesive Remnant Index (ARI). MATERIALS AND METHODS: Four experimental adhesive groups were created: group 1 was an unfilled urethane-dimethacrylate (UDMA) adhesive, group 2 consisted of UDMA and a filler content of 30 vol%, group 3 consisted of UDMA and a filler content of 50 vol%, and group 4 was manufactured with a filler level of 70 vol% in a UDMA matrix. The embedded filler was silicon dioxide. After etching and priming, stainless steel brackets were bonded to extracted human third molars (n = 60) with the experimental adhesives (15 teeth per group). After storage in distilled water for 72 hours, shear bond strength and ARI scores were evaluated. Kruskal-Wallis and post hoc test were performed for statistical analysis. RESULTS: Shear bond strength of UDMA-based adhesives depends on filler content. Higher adhesive filler levels reveal greater bond strength between enamel and stainless steel brackets. ARI scores showed no significant difference among the groups. However, higher filled adhesives (filler content 70 vol%) seem to present higher ARI scores. CONCLUSION: Highly filled UDMA adhesives offer greater bond strength than do lower filled or unfilled resins.

• WITHDRAWN: Variations of maximum mouth-opening capacity and condylar path length during growth period in children.

  Authors: Claudia Reicheneder, Tomas Gedrange, Mouayyad Baqaien, Dieter Müβig

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 06/2007;

  This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

• Secondary palatal closure in rats in association with relative maternofetal levels of folic acid, vitamin B12, and homocysteine.

  Authors: Jens Weingärtner, Sergei Maile, Peter Proff, Claudia Reicheneder, Volker Bienengräber, Jochen Fanghänel, Tomas Gedrange

  Annals of anatomy = Anatomischer Anzeiger : official organ of the Anatomische Gesellschaft. 02/2007; 189(3):229-33.

  Animal experiments are used in embryological and teratological studies of matters relevant to humans. In gravid rats, a decrease in the levels of folic acid and vitamin B12 was observed in maternalAnimal experiments are used in embryological and teratological studies of matters relevant to humans. In gravid rats, a decrease in the levels of folic acid and vitamin B12 was observed in maternal blood and in amniotic fluid. At the time of secondary palatal closure (14th day of pregnancy), the folic acid level of the amniotic fluid was 73% lower than that of the maternal blood. A drop in vitamin B12 in conjunction with an increase in amniotic homocysteine levels is seen as a risk factor for malformation of the palate. The understanding of causes of cleft generation could lead to a prophylactic treatment approach.

• Experimental composite brackets: influence of filler level on the mechanical properties.

  Authors: Andreas Faltermeier, Martin Rosentritt, Claudia Reicheneder, Dieter Müssig

  American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 01/2007; 130(6):699.e9-14.

  INTRODUCTION: Despite their popularity in satisfying esthetic demands, plastic brackets still have some disadvantages because of decreased wear resistance and hardness. Our aim in this study was toINTRODUCTION: Despite their popularity in satisfying esthetic demands, plastic brackets still have some disadvantages because of decreased wear resistance and hardness. Our aim in this study was to investigate the mechanical properties of an alternative bracket-polymer urethane-dimethacrylate (UDMA) reinforced by silicon dioxide fillers with several filler levels. METHODS: Three bracket groups were created: (1) unfilled UDMA, (2) UDMA with a filler content of 40% by volume, and (3) UDMA with a filler content of 70% by volume. Flexural strength, fracture force, and Vickers hardness of the bracket groups were tested. In addition, a 3-medium wear test was performed. RESULTS: The filler-reinforced brackets showed increased hardness, greater stiffness, and improved wear resistance compared with unfilled brackets. Higher filler concentrations in a polymer matrix result in greater stiffness of the polymer. Despite this, the filled composite brackets were not statistically more susceptible to fractures than the unfilled plastic brackets. CONCLUSIONS: Experimental UDMA brackets reinforced with silicon dioxide fillers showed an obvious trend for improved mechanical properties compared with unfilled UDMA brackets.