Scanning microwave microscopy applied to semiconducting GaAs structures.

A calibration algorithm based on one-port vector network analyzer (VNA) calibration for scanning microwave microscopes (SMMs) is presented and used to extract quantitative carrier densities from a semiconducting n-doped GaAs multilayer sample. This robust and versatile algorithm is instrument and frequency independent, as we demonstrate by analyzing experimental data from two different, cantilever- and tuning fork-based, microscope setups operating in a wide frequency range up to 27.5 GHz.

Exposure of patient and dental staff to fine and ultrafine particles from scanning spray.

Objectives: Sprays containing fine and ultrafine particles are commonly used for optical scanning. The aim of this study was to measure the particle exposure of patient and dentist during application of scanning spray and to evaluate measures for its reduction.

Materials And Methods: A lower molar in a dental simulator was powdered with scanning spray.

Reversal mechanism of an individual Ni nanotube simultaneously studied by torque and SQUID magnetometry.

Using an optimally coupled nanometer-scale SQUID, we measure the magnetic flux originating from an individual ferromagnetic Ni nanotube attached to a Si cantilever. At the same time, we detect the nanotube's volume magnetization using torque magnetometry. We observe both the predicted reversible and irreversible reversal processes.

Cantilever magnetometry of individual Ni nanotubes.

Recent experimental and theoretical work has focused on ferromagnetic nanotubes due to their potential applications as magnetic sensors or as elements in high-density magnetic memory. The possible presence of magnetic vortex states-states which produce no stray fields-makes these structures particularly promising as storage devices. Here we investigate the behavior of the magnetization states in individual Ni nanotubes by sensitive cantilever magnetometry.

Multicenter randomized clinical trial: early loading of implants in maxillary bone.

Purpose: The aim of this study was to show prognostic equivalence between implant loading in the maxilla after 12 weeks versus 4 weeks.

Materials And Methods: One hundred four patients, from four centers in this open-labeled randomized multicenter prospective controlled clinical trial, were assigned to either 12 weeks or 4 weeks of unloaded healing. Two hundred sixty-nine implants (sand blasted large-grid, acid etched [SLA] surface, ≥ 4.

Development of a validated process for manual preparation of dental transmission instruments.

The goal of the study was to develop a validated manual preparation process that conforms to the requirements of validation guidelines. Twelve dental transmission devices from various manufacturers (turbines, handpieces, and contra-angle handpieces) were artificially contaminated with bovine hemoglobin for the test. Ten microliters (corresponding to 800 μg) of bovine hemoglobin solution (concentration 80 mg/ml) was pipetted into the spray water and spray air channels.

[Coincident manifestation of mesotheliomas of the tunica vaginalis and pleura. Case report and literature overview].

Malignant mesotheliomas are rare entities (0.1-0.2% of all malignant tumors) possibly localized at the pleura, peritoneum, pericardium, and tunica vaginalis.

Malignant fibrous histiocytoma of the face: report of a case.

Background: Soft tissue sarcomas in the head and neck region are rare and often present a difficult differential diagnosis. The aim of our presentation is to point out the complexity of the diagnosis, treatment and follow up.

Case Presentation: An eighty-seven year old female patient was referred to our unit with a fast growing brownish lump on the face.

Success rate of mini- and micro-implants used for orthodontic anchorage: a prospective clinical study.

Objectives: Whereas micro-implants have become a useful alternative as orthodontic anchorage elements in orthodontics, less is known about the clinical effectiveness of micro-implants. The aim of this prospective clinical study was to evaluate the success rate of micro-implants used for orthodontic anchorage.

Material And Methods: A total of 133 mini-implants (79 Abso Anchor, 54 Dual Top implants) placed in 49 patients to support orthodontic tooth movements were examined in the study.

[Induction of urothelial carcinoma due to chronic arsenic ingestion? A occupational medicine-toxicological excursion].

Whether chronic intoxication with arsenic can induce cancer of the urinary tract is an important question in urology and occupational medicine. Here, we consider potential exposure, and discuss the epidemiology and toxicology of arsenic. In addition, we conceptualize a possible strategy for clinical procedures.

Load-related bone modelling at the interface of orthodontic micro-implants.

The purpose of this study was to determine the interface reaction of two different titanium micro-implant systems activated with different load regimens. A total of 200 micro-implants (100 Abso Anchor and 100 Dual Top) were placed in the mandible of eight Göttinger minipigs. Two implants each were immediately loaded in the opposite direction by various forces (100, 300 or 500 cN) through tension coils.

Fast element mapping of titanium wear around implants of different surface structures.

The effect of unintended titanium release around oral implants remains a biological concern. The current study was undertaken to evaluate a new detection system of element mapping in biological probes. A new scanning electron microscopy-energy dispersive spectroscopy detection method was used to map the features of titanium contamination in peri-implant bone around implants with different surface structures.

Image-based extracorporeal tissue engineering of individualized bone constructs.

Purpose: Computer-aided technologies have been recently employed for use in extracorporeal bone tissue engineering strategies. In this pilot animal experimental study, the intention was to test whether autologous osteoblast-like cells cultured in vitro on individualized scaffolds can be used to support bone regeneration in a clinical environment.

Materials And Methods: For this purpose, mandibular bone defects were surgically introduced into the mandibles of minipigs and the scaffold of the defect site was modeled by computer-aided design/computer-aided manufacturing technique.

Vascular basis of mucosal color.

Background: Besides the color of the teeth the color of the alveolar gingiva plays a crucial role in esthetic rehabilitation in dento-alveolar treatment. Whereas nowadays the color of the teeth can be determined exactly and individually, the specific influence of the red color of the gingiva on treatment has not been assessed yet. The aim of this study was to evaluate the vascularization as the basis for gingival esthetics.

Strain driven fast osseointegration of implants.

Background: Although the bone's capability of dental implant osseointegration has clinically been utilised as early as in the Gallo-Roman population, the specific mechanisms for the emergence and maintenance of peri-implant bone under functional load have not been identified. Here we show that under immediate loading of specially designed dental implants with masticatory loads, osseointegration is rapidly achieved.

Methods: We examined the bone reaction around non- and immediately loaded dental implants inserted in the mandible of mature minipigs during the presently assumed time for osseointegration.

Incision design in implant dentistry based on vascularization of the mucosa.

Objectives: The delivery of an adequate amount of blood to the tissue capillaries for normal functioning of the organ is the primary purpose of the vascular system. Preserving the viability of the soft tissue segment depends on the soft tissue incision being properly designed in order to prevent impairment of the circulation. A knowledge of the course of the vessels as well as of their supply area are crucial to the decision of the incision.

Interface reaction at dental implants inserted in condensed bone.

Purpose: The influence of the osteotome technique on the interface reaction of cylinder implants (SLA, ITI) was compared with the interface reaction of conventional implant insertion in an animal model.

Material And Methods: A total of 64 implants were placed in the cranial and caudal tibia of 8 Göttinger minipigs. The implant site was prepared either by a conventional technique with drills (control group A) or by the osteotome technique (experimental group B).

[Aggressive fibromatosis in the jaw and facial region with bone involvement. A review].

Background: Aggressive fibromatosis (AF) involving bones of the head is rare and surgery is often complicated by a high recurrence rate. Interdisciplinary treatment is of the utmost importance to avoid extensive, mutilating resection. Two cases emphasize the difficulties in the management.

Load-related implant reaction of mini-implants used for orthodontic anchorage.

The purpose of this study was to determine the clinical and biomechanical outcome of two different titanium mini-implant systems activated with different load regimens. A total of 200 mini-implants (102 Abso Anchor and 98 Dual Top) were placed in the mandible of eight Göttinger minipigs. Two implants each were immediately loaded in opposite direction by various forces (100, 300 or 500 cN) through tension coils.

Design and performance of a bioreactor system for mechanically promoted three-dimensional tissue engineering.

There is currently considerable interest in increasing the response of mesenchymal cells to physical forces, and numerous loading devices have been used to increase the formation of skeletal tissue in vivo and in vitro. We have developed a bioreactor system to apply cyclic strains on three-dimensional specimens over a range of 0-20,000 mustrain. The piezoelectric-driven mechanism allows the precise adjustment and control over load-related deformations of tissue, as shown by finite-element calculations of deformation of a collagen gel under load.

Basic reactions of osteoblasts on structured material surfaces.

In order to assess how bone substitute materials determine bone formation in vivo it is useful to understand the mechanisms of the material surface/tissue interaction on a cellular level. Artificial materials are used in two applications, as biomaterials alone or as a scaffold for osteoblasts in a tissue engineering approach. Recently, many efforts have been undertaken to improve bone regeneration by the use of structured material surfaces.

Biological and biomechanical evaluation of bone remodelling and implant stability after using an osteotome technique.

The influence of the osteotome technique on the osseointegration and biomechanical behaviour of cylinder implants (SLA, ITI was compared with conventional preparation of the implant site in an animal model. A total of 56 implants were placed in the cranial and caudal tibia condyle of six Gottinger minipigs. The implant site was prepared either by the conventional technique with drills (control group A) or by the osteotome technique (experimental group B).

[Peri-implant bone formation around cylindrical and conical implant systems].

Background: The treatment of patients with early or immediately loaded dental implants has renewed interest in the behavior of osseointegration at the implant surface. Whereas it is generally accepted that peri-implant tissue formation and mineralization are dependent on the local mechanical environment in the interface zone, controversies exist concerning the impact of implant design on peri-implant bone formation. The aim of the present study was the in vivo evaluation of peri-implant bone formation by two different implant systems: cylindrical (ITI) versus conical (ILI).