Biomedical subjects

Andreas Schlegel

Publications and source records attributed to Andreas Schlegel.

6 recordsLinked to original sources

PubMed2006

Dynamic periosteal elevation.

The osteoinductive potential of the periosteum can be stimulated by raising the periosteum using a type of distraction. This was tested and confirmed in an animal experiment in 6 Goettingen minipigs. A titanium mesh was implanted beneath the periosteum and then raised. Bone formed underneath the mesh, with rows of micro-pillars similar to those found after osteodistraction. The main advantages of dynamic periosteal elevation are that invasion and morbidity are minimal. Clinically it might be applicable in craniomaxillofacial surgery, in augmentation before implantation, and in reconstruction of the skull.

Animals↗

PubMed2006

Rapid induction of hypnosis by finger elongation: a brief communication.

This clinical pilot study on finger elongation for induction of hypnosis attempts to determine whether the observed response is a hypnotic phenomenon or a simple physiologic reaction. Sixteen volunteers participated in the 5-phase study, which measured relative and absolute changes in the length of each finger prior to and after each phase. A distinctive elongation was statistically significant for the hypnosis condition. In addition, findings suggest changes in the metacarpus. Further investigation is indicated to shed light on this apparent phenomenon.

Fingers↗

PubMed2006

Neurophysiologic and long-term effects of clinical hypnosis in oral and maxillofacial treatment--a comparative interdisciplinary clinical study.

This prospective comparative clinical study evaluated the effectiveness of clinical hypnosis and its long-term effect in oral and maxillofacial treatment. A total of 45 highly anxious and nonanxious subjects were evaluated by subjective experience and objective parameters. Parameters were EEG, ECG, heart rate, blood pressure, blood oxygen saturation, respiration rate, salivary cortisol concentration, and body temperature. During and subsequent to the operative treatment, hypnosis led to a significant reduction of systolic blood pressure, and respiration rate and to significant changes in the EEG. The subjective values of the parameters evaluated existing anxiety mechanisms and patterns and possible strategies to control them, whereas the objective parameters proved the effectiveness of hypnosis and its long-term effect.

Anxiety↗

PubMed2005

The bone-metal interface of defect and press-fit ingrowth of microwave plasma-chemical vapor deposition implants in the rabbit model.

PURPOSE: The histological differences between the defect and contact areas of the implant surface to bone were tested in 35 New Zealand White rabbits in a standardized model. Microwave plasma chemical vapor-coated implant probes were tested in control and uncoated materials. MATERIAL AND METHODS: In each femur of 35 rabbits, cylindrical implant rods with a planed side were inserted. Three groups, divided in coated and uncoated material at half, were observed 42, 84 and 168 days. The probes were examined histologically for bone-implant contact in the curved and plane (defect area) sides. RESULTS: Generally the bone-implant contact seems to be nearly constant in time in the curved area of coated and uncoated probes. Here the implant was inserted in the press-fit mode. Diamond-coated probes showed similar bone-implant contact (51.9% (42 days), 62.5% (84 days), 56.1% (168 days)) compared to uncoated material (56.2%, 65.4%, 62.9%). The defect area (plane side) had no bone-implant contact at the time of insertion and showed increasing values on longer observation times with only significant differences in the 42-day group between coated (17.85%, 35.2%, 47.7%) and uncoated materials (35.5%, 40.55%, 51.81%). CONCLUSION: The evaluation of the curved side of the implant probe showed no great variation of bone-implant contact within the described observation times. This model simulates the usual implant insertion situation. The diamond-coated material becomes osseointegrated at a later time point. The bone-implant contact was only statistically relevant in one group in comparison to uncoated material.

Alloys↗

PubMed2004

Sensor-based laser ablation for tissue specific cutting: an experimental study.

The interaction of laser light and tissue causes measurable phenomenons. These phenomenons can be quantified and used to control the laser drilling within a feedback system. Ten halves of dissected minipig jaws were treated with an Er:YAG laser system controlled via a feedback system. Sensor outputs were recorded and analyzed while osteotomy was done. The relative depth of laser ablation was calculated by 3D computed tomography and evaluated histologically. The detected signals caused by the laser-tissue interaction changed their character in a dramatic way after passing the cortical bone layer. The radiological evaluation of 98 laser-ablated holes in the ten halves showed no deeper ablation beyond the cortical layer (mean values: 97.8%). Histologically, no physical damage to the alveolar nerve bundle was proved. The feedback system to control the laser drilling was working exactly for cortical ablation of the bone based on the evaluation of detected and quantified phenomenon related to the laser-tissue interaction.

Animals↗

PubMedDate not supplied

The endoscopically controlled osteotome sinus floor elevation: a preliminary prospective study.

PURPOSE: It was the aim of the present prospective study to quantify the gain in height of implant sites by endoscopically controlled osteotome sinus floor elevations (ECOSFE) with simultaneous implant placement and to report the number of sinus membrane perforations. MATERIALS AND METHODS: From October 1999 to December 2000, of 92 sinus floor elevations, 18 were carried out endoscopically controlled with an osteotome technique. As augmentation material, beta-tricalcium phosphate (beta-TCP) or autogenous bone was used; 22 implants were placed. RESULTS: The residual height of the alveolar crest in the posterior maxilla was 6.8 +/- 1.6 mm on average. The implant lengths ranged from 10 to 16 mm (mean implant length 12.2 +/- 1.4 mm). They were significantly larger than the residual height of the alveolar crests (P < .0005). Elevation of the sinus floor with an osteotome had to be supported by conventional sinus floor elevation instruments after a mean elevation of 3.0 +/- 0.8 mm to prevent perforation of the sinus membrane. However, 1 perforation occurred, which was repaired with a periosteal patch. At stage 2 surgery, 2 implants were removed because of mobility. Endoscopic control revealed one case in which beta-TCP could be found within the sinus; another case showed areas of polypoid mucosa on the sinus floor. DISCUSSION: With the ECOSFE, perforations of the sinus membrane can be visualized; however, they cannot be avoided. Although this technique is less invasive than the lateral window technique, it cannot be recommended as a standard procedure in the posterior maxilla because of the large amount of additional equipment needed and the technically demanding procedure. CONCLUSION: The use of the ECOSFE should be confined to scientific trials.

Adult↗