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Biomedical subjects

Christian Sander

Publications and source records attributed to Christian Sander.

At least 19 recordsLinked to original sources
PubMed2006

Initial results regarding force exertion during rapid maxillary expansion in children.

AIM AND METHOD: We developed a method to measure the forces occurring during rapid maxillary expansion and carried out the University of Ulm rapid maxillary expansion method, similar to that of Chatellier and Chateau, in ten patients. RESULTS: The forces occurring on the maxilla increased up to 120 N. There was considerable variation in force level from patient to patient. After "rupture" of the midpalatal suture, the forces decreased. The remaining forces seemed to be the result from stress on soft tissue and bone.

Adolescent↗
PubMed2006

Leveling of the second molar with a superelastic spring.

BACKGROUND: Second permanent molars often erupt during fixed appliance treatment. When they are to be incorporated into the fixed appliance, it is often not possible to bond the buccal tube in the correct position. MATERIAL AND METHODS: We describe herein a method for aligning second permanent molars by means of a superelastic segmental archwire. This involves the application of a rigid steel archwire extending from the right first molar to the left first molar for anchorage. This method was investigated in-vitro and in its clinical application. The in-vitro test was carried out with a hexapode simulating the vertical deviation of the second molar. RESULTS: A .016'' x .022'' stainless steel archwire achieved forces of 13 N; a TMA archwire attained 5 N (both with a deflection of 2 mm), and the superelastic late-leveler achieved a maximum force of 1.3 N with a 5 mm deflection. The maximum uprighting torquing moments were 55 Nmm with the stainless steel archwire, 25 Nmm with the TMA archwire and 2 mm deflection, and 4 Nmm with the late-leveler and 5 mm deflection. CONCLUSIONS: The forces and moments of stainless-steel and TMA archwires are too high for the alignment of second permanent molars. The moderate forces and moments occurring with the superelastic late-leveler are capable of intruding, derotating and uprighting the second molar. The vertical component prevents artificial opening of the bite.

Alloys↗
PubMed2006

Alignment of displaced or impacted teeth with the traction chain.

To align those teeth in the dental arch that cannot erupt or are displaced, they must be surgically exposed. After the traction device is attached, the tooth is again covered with the mucoperiosteal flap to protect the tissues involved. For this reason, the loss of this traction device must be absolutely avoided in order to prevent another surgical intervention. Here at the University of Ulm, we have developed and tested an optimized traction chain for that purpose. The chain is attached to the tooth with a laser-roughened pad applying the acid-etching technique. The chain links serve as fixation elements for traction devices such as elastic ligatures or piggyback archwires. At the same time, one can determine the distance covered by the tooth by the number of the erupting chain links. We demonstrate the clinical application of this traction device in two cases.

Child↗
PubMed2006

Dental care during orthodontic treatment with electric toothbrushes.

OBJECTIVE: In an in-vitro experimental set-up, we tested the efficacy of different electric toothbrushes in cleaning teeth with a multibracket appliance. MATERIAL AND METHODS: The efficacy of three sonic and four rotating toothbrushes were compared; the brushes removed artificial plaque from plastic teeth. The amount of removed plaque substitute was determined via a comparative photo-analysis with one picture of the teeth before and one picture after the brushing cycle. Two views of the tooth segment were chosen: one vestibular view and one apical view of the areas behind the bracket wings. All tests were carried out with water, elmex and Pearls and Dents as brushing media. RESULTS: The data showed greater brushing efficacy when Pearls and Dents toothpaste was used. The Sonicare toothbrush was the most efficient. The Sonicmax and rotating Oral-B ProfessionalCare 7000 were also very efficacious. On average, all the other toothbrushes performed less well. All toothbrushes were capable of brushing the undercut areas behind the bracket wings, with plaque removal being the greatest when the Sonicare toothbrush was used together with Pearls and Dents. CONCLUSIONS: The best electric toothbrushes did not demonstrate good tooth cleaning. Longer brushing times, mastery of the proper brushing technique, and/or special toothbrush heads are absolutely necessary.

Dental Care↗
PubMed2006

The derotation of premolars and canines with NiTi elements.

BACKGROUND: Canines or premolars must often be derotated during fixed appliance therapy. If such derotation is carried out on the continuous archwire during the leveling phase, it may lead to unwanted side effects on the neighboring teeth. MATERIAL AND METHODS: At the University of Ulm a .018" x .018" nickel-titanium segmental derotation archwire was developed to start derotation as early as possible. This wire can be inserted during leveling. This system consists of a vertical slot bracket, an elastic ligature, and the derotation archwire. We tested the derotation archwire under clinical application. The occurring forces and torquing moments were measured in vitro via a hexapode and a sensor working in three dimensions. RESULTS: In this investigation, a derotation moment of 12 Nmm occurred in the canine with a 140 degrees archwire rotation and a force in lingual direction. This archwire also made overcorrection possible, since it remains active after complete derotation. A complete derotation of the tooth was effected with no reactivation, due to the wire's superelasticity.

Bicuspid↗
PubMed2006

Detection of clonal rearrangement of T-cell receptor genes in the diagnosis of primary cutaneous CD30 lymphoproliferative disorders.

BACKGROUND: Detection of clonality has been reported to be a helpful tool in the diagnosis of cutaneous lymphomas. Monoclonal rearrangement of T-cell receptor genes (TCR) was reported in fresh frozen tissue of lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (ALCL), but the diagnostic value of T-cell clonality in formalin-fixed, paraffin-embedded biopsies has so far not been assessed. METHODS: Detection of clonal rearrangement of TCRgamma genes by highly sensitive polymerase chain reaction-based automated high-resolution fragment analysis (AHRFA) in archival LyP (n = 18) and ALCL (n = 17) tissue. RESULTS: Detection of clonality differed significantly among the histologic forms of LyP as well as between LyP and ALCL with clonality found in none of the 10 biopsies of LyP type A and B, in 4/8 (50%) of the LyP type C specimens, and in 11/17 (65%) of ALCL cases. CONCLUSIONS: T-cell clonality can only be found in a minority (four of 18; 22%) of archival LyP specimens, even when employing a highly sensitive detection method and is thus of limited diagnostic value. Final diagnosis of LyP has to be based mainly on clinical, histologic, and immunohistochemical findings rather than on results of clonality studies.

Adult↗
PubMed2005

WHO-EORTC classification for cutaneous lymphomas.

Primary cutaneous lymphomas are currently classified by the European Organization for Research and Treatment of Cancer (EORTC) classification or the World Health Organization (WHO) classification, but both systems have shortcomings. In particular, differences in the classification of cutaneous T-cell lymphomas other than mycosis fungoides, Sezary syndrome, and the group of primary cutaneous CD30+ lymphoproliferative disorders and the classification and terminology of different types of cutaneous B-cell lymphomas have resulted in considerable debate and confusion. During recent consensus meetings representatives of both systems reached agreement on a new classification, which is now called the WHO-EORTC classification. In this paper we describe the characteristic features of the different primary cutaneous lymphomas and other hematologic neoplasms frequently presenting in the skin, and discuss differences with the previous classification schemes. In addition, the relative frequency and survival data of 1905 patients with primary cutaneous lymphomas derived from Dutch and Austrian registries for primary cutaneous lymphomas are presented to illustrate the clinical significance of this new classification.

Humans↗
PubMed2005

Dental care with manual toothbrushes during fixed orthodontic treatment--a new testing procedure.

AIM: The aim of this investigation was to employ a new in-vitro testing system for manual toothbrushes in order to distinguish the more effective from those less so for dental care during fixed appliance treatment. MATERIALS AND METHODS: The testing apparatus consisted of a sliding carriage able to execute a horizontal brushing movement, and a row of artificial teeth upon which the various toothbrushes were manipulated. The artificial row of teeth was fixed on a sensor that recorded in all three dimensions the forces and moments caused by the toothbrushes on the toothbrush field. All the tests were executed with a weight of 110 g on a tooth field with a multibracket appliance. Tests were also carried out with five toothbrushes having weights of 200 g, 250 g and 300 g. Here, the decisive target values were 1) the degree of exertion necessary in the brushing direction to move a brush over the artificial teeth, and 2) the maximum force occurring in the brushing direction. High target values indicated high interaction between toothbrush bristles and the surfaces being brushed. RESULTS: From testing five toothbrushes with four different weights, we have established profiles confirming the beneficial and less beneficial properties of certain toothbrushes involving various high contact forces.

Dental Devices, Home Care↗
PubMed2005

Defining early mycosis fungoides.

This editorial review summarizes the results of 5 meetings sponsored by the International Society for Cutaneous Lymphoma at which the clinicopathologic and ancillary features of early mycosis fungoides were critically examined. Based on this analysis, an algorithm was developed for the diagnosis of early mycosis fungoides involving a holistic integration of clinical, histopathologic, immunopathologic, and molecular biological characteristics. A novel aspect of this algorithm is that it relies on multiple types of criteria rather than just one, for example, histopathology. Before its finalization, the proposed diagnostic algorithm will require validation and possibly further refinement at multiple centers during the next several years. It is anticipated that a more standardized approach to the diagnosis of early mycosis fungoides will have a beneficial impact on the epidemiology, prognostication, treatment, and analysis of clinical trials pertaining to this most common type of cutaneous lymphoma.

Algorithms↗
PubMed2005

WHO/EORTC classification of cutaneous lymphomas 2005: histological and molecular aspects.

UNLABELLED: The new WHO/EORTC classification for cutaneous lymphomas comprises mature T-cell and natural killer (NK)-cell neoplasms, mature B-cell neoplasms, and immature hematopoietic malignancies. It reflects the unique features of lymphoproliferative diseases of the skin, and at the same time it is as compatible as possible with the concepts underlying the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. This article reviews the histological, phenotypical, and molecular genetic features of the various nosological entities included in this new classification. These findings always have to be interpreted in the context of the clinical features and biologic behavior. AIM: To review the histological, phenotypical and molecular genetic features of the various nosological entities of the new WHO/EORTC classification for cutaneous lymphomas. METHODS: Extensive review of the literature cited in Medline and own data of the authors. RESULTS: The WHO/EORTC classification of cutaneous lymphomas comprises mature T-cell and NK-cell neoplasms, mature B-cell neoplasms and immature hematopoietic malignancies. It reflects the unique features of primary cutaneous lymphoproliferative diseases. CONCLUSION: This classification is as much as possible compatible with the concept of the WHO classification for nodal lymphomas and the EORTC classification of cutaneous lymphomas. The histological, phenotypical and molecular genetic features always have to be interpreted in the context of the clinical features and biologic behavior.

Europe↗
PubMed2004

Development and biomechanical investigation of a new compound palatal arch.

BACKGROUND AND AIM: There are many advantages in using a transpalatal arch in orthodontic treatment. In addition to the active movement of individual teeth, such an arch can be used to provide additional anchorage. The aim of this study was to further develop and improve both the clinical and the biomechanical properties of the conventional transpalatal arch. MATERIAL AND METHODS: Currently available compound material components form an established part of orthodontic therapy. The Compound palatal arch broadens the scope of this treatment system. The biomechanical effects of the newly developed Compound palatal arch were verified by comparing them with those of commercially available conventional transpalatal arches. The recently developed Compound palatal arch is made of one compound element: nickel-titanium/stainless steel. The specific dimensions and design of the nickel-titanium element are aimed at exploiting its superelasticity, even during active molar movement. The biomechanical investigation was carried out using six-component measuring sensors to register the forces and moments in the three spatial dimensions (x, y and z) at 37 degrees C. The following appliances were investigated: Goshgarian transpalatal arch, quad-helix appliance, Arndt memory expander, and Compound palatal arch. RESULTS: Transpalatal arches could not be inserted without the arch being under tension. This is particularly important when the arch is being used for anchorage purposes. The Goshgarian arch had to be classified as problematic for the movement of single teeth as the load/deflection rate was high. However, this can be utilized for anchorage purposes. The clinical advantage of a quad-helix appliance is the option for asymmetric tooth movement. CONCLUSIONS: This study showed that the quad-helix was effective for both unilateral and bilateral derotation as well as for transversal tooth movement. However, expansions should be confined to < or = 4 mm, and derotations to < 10 degrees, as forces and moments are otherwise not within the physiologic range. The Arndt memory expander displayed no advantages over either the quad-helix appliance or the Goshgarian transpalatal arch. Nor did it display any superelastic properties. The linear relationship, the relatively high forces and moments, and the lack of clinical adjustability cast doubts on the benefits of this appliance. The newly developed Compound palatal arch showed substantial advantages in molar derotation compared with conventional transpalatal arches. Superelastic properties were achieved through the design and positioning of the nickel-titanium element. Expansion with the Compound palatal arch was comparable with that with conventional transpalatal arches. The clinical advantage is in the fact that this appliance can be reactivated and that dental asymmetries can be treated.

Activator Appliances↗
PubMed2004

The influence of intermittent forces during daytime application of the SIII appliance.

Daytime application of the SIII appliance results in mainly intermittent forces. Permanent force occurs only for a few minutes, if at all. These intermittent forces may be as high as 40 N in individual cases. Depending upon the patient's activity and temperament, 10 to more than 100 intermittent force impulses per minute can occur. The intermittent forces account for the therapeutic effects found in young patients.

Bite Force↗
PubMed2004

Visualisation of tissue kallikrein, kininogen and kinin receptors in human skin following trauma and in dermal diseases.

During dermal injury and inflammation the serine proteases kallikreins cleave endogenous, multifunctional substrates (kininogens) to form bradykinin and kallidin. The actions of kinins are mediated by preferential binding to constitutively expressed kinin-B2 receptors or inducible kinin-B1 receptors. A feature of the kinin-B1 receptors is that they show low levels of expression, but are distinctly upregulated following tissue injury and inflammation. Because recent evidence suggested that kinin-B1 receptors may perform a protective role during inflammation, we investigated the specific occurrence of the kallikrein-kinin components in skin biopsies obtained from normal skin, patients undergoing surgery, basalioma, lichenificated atopic eczema, and psoriasis. The tissue was immunolabeled in order to determine the localisation of tissue pro-kallikrein, kallikrein, kininogen and kinin receptors. The kinin components were visualised in normal, diseased and traumatised skin, except that no labelling was observed for kininogen in normal skin. Of the five types of tissue examined, upregulation of kinin-B1 receptors was observed only in skin biopsies obtained following surgery. In essence, the expression of kinin-B1 receptors did not appear to be enhanced in the other biopsies. Within the multiple steps of the inflammatory cascade in wound healing, our results suggest an important regulatory role for kinin-B1 receptors during the first phase of inflammation following injury.

Aged↗
PubMed2003

Cytotoxic/natural killer cell cutaneous lymphomas. Report of EORTC Cutaneous Lymphoma Task Force Workshop.

BACKGROUND: Cutaneous lymphomas expressing a cytotoxic or natural killer (NK) cell phenotype represent a group of lymphoproliferative disorders for which there is currently much confusion and little consensus regarding the best nomenclature and classification. METHODS: This study analyzes 48 cases of primary cutaneous lymphoma expressing cytotoxic proteins and/or the NK cell marker, CD56. These cases were collected for a workshop of the European Organization for Research and Treatment of Cancer Cutaneous Lymphoma Task Force, to better clarify the clinical, morphologic, and phenotypic features of these uncommon tumors. RESULTS: Several categories with different clinical and pathologic features were delineated: 1) aggressive, CD8+, epidermotropic, cytotoxic T-cell lymphoma; 2) mycosis fungoides, cytotoxic immunophenotype variant; 3) subcutaneous panniculitis-like T-cell lymphoma; 4) NK/T-cell lymphoma, nasal type; 5) CD4+, NK cell lymphoma; 6) blastoid NK cell lymphoma; (7) intravascular NK-like lymphoma; and 8) cytotoxic, peripheral T-cell lymphoma. CONCLUSIONS: Our data show that primary cutaneous cytotoxic/NK cell lymphomas include distinct groups of diseases, clinically, histologically, and biologically. Because the finding of a cytotoxic phenotype often has prognostic significance, the routine use of cytotoxic markers in the diagnosis and classification of cutaneous lymphomas should be expanded.

CD4-Positive T-Lymphocytes↗
PubMed2003

Expression of stratum corneum chymotryptic enzyme in ichthyoses and squamoproliferative processes.

OBJECTIVE: Stratum corneum chymotryptic enzyme (SCCE) is a serine protease, which is thought to play a role in the desquamation of skin via the proteolysis of desmosomes in the stratum corneum. The objective of this study was to investigate the expression of SCCE in ichthyoses and squamoproliferative processes, conditions in which the shedding and replacement of epidermal cells is disrupted. DESIGN: Tissue samples from cases of Netherton's syndrome, congenital ichthyosiform erythroderma, ichthyosis vulgaris, actinic keratosis, squamous cell carcinoma in situ, and invasive squamous cell carcinoma were examined for expression of SCCE using immunohistochemistry. MAIN OUTCOME MEASURES: The slides were qualitatively analyzed for the expression of SCCE by a certified dermatopathologist. RESULTS: In all disease states, we found that the expression of SCCE was absent in areas of parakeratotic stratum corneum of normal thickness. In areas of mixed orthokeratosis and parakeratosis where the stratum corneum was greatly thickened as might correspond clinically to a cutaneous horn, SCCE staining was either absent or focally aggregated without regard to orthokeratosis or parakeratosis. Of note, complete absence of SCCE expression was not observed in any of the cases of ichthyosis examined, nor was there increased expression of SCCE in the atypical cells of the squamoproliferative disorders. CONCLUSIONS: These results suggest that SCCE is abnormally expressed in skin where epidermal cell kinetics are disrupted due to inherited and acquired defects. Further investigation is needed to determine causality between the abnormal expression of SCCE and the altered cell kinetics in these diseases.

Carcinoma in Situ↗
PubMed2002

Single-cell analysis of CD30+ cells in lymphomatoid papulosis demonstrates a common clonal T-cell origin.

Lymphomatoid papulosis (LyP) represents an intriguing cutaneous T-cell lymphoproliferative disorder with a histologic appearance resembling malignant lymphoma. This finding strongly contrasts with the benign clinical course of the disease. However, in 10% to 20% of cases, LyP can precede, coexist with, or follow malignant lymphoma. In these cases, the same T-cell population has been shown to be present in the LyP as well as in the associated lymphoma. In most LyP cases, there is-despite the sometimes extremely long course of the disease-no evolution of a secondary lymphoma. The investigation of these uncomplicated LyP cases for the presence of clonal T-cell receptor rearrangements has produced heterogeneous results. This might be explained by biologic or technical reasons arising from analyzing whole tissue DNA extracts. To definitively clarify whether the large atypical CD30(+) cells in LyP without associated lymphoma all belong to the same clone or represent individually rearranged T cells, we analyzed the T-cell receptor-gamma rearrangements of single CD30+ as well as of single CD30- cells isolated from 14 LyP lesions of 11 patients. By using this approach we could demonstrate that the CD30+ cells represent members of a single T-cell clone in all LyP cases. Moreover, in 3 patients the same CD30+ cell clone was found in anatomically and temporally separate lesions. In contrast, with only a few exceptions, the CD30- cells were polyclonal in all instances and unrelated to the CD30+ cell clone. Our results demonstrate that LyP unequivocally represents a monoclonal T-cell disorder of CD30+ cells in all instances.

Adult↗