Bone regeneration with glass ceramic implants and calcium phosphate cements in a rabbit cranial defect model.

Hydroxyapatite cement (BoneSource®) and brushite calcium phosphate cement (chronOS™ Inject) were tested for fixation of glass ceramic implants (Bioverit®) in experimentally created cranial defects in 24 adult New Zealand White rabbits. Aim of the in vivo study was to assess and compare the biocompatibility and osseointegration of the implanted materials. Macroscopic and histological evaluations were performed 1 month, 3 months, and 6 months postoperatively. All implanted materials were well tolerated by the surrounding tissue. Both bone cements exhibited osteoconductive properties. Differences could be detected regarding to the rates of cement resorption and new bone formation. The brushite cement was resorbed faster than the hydroxyapatite cement. The chronOS™ Inject samples exhibited a higher rate of connective tissue formation and an insufficient osseointegration. BoneSource® was replaced by bone with minimal invasion of connective tissue. New bone formation occurred faster compared to the chronOS™ Inject group. Bioverit® implants fixed with BoneSource® were successfully osseointegrated.

[Problems in the development of a comprehensive three-dimensional databank of the human skull for the preoperative preparation of an exact implant for the treatment of bone defects]. / Problematik des Aufbaus einer Datenbank dreidimensional erfasster menschlicher Schädel als Voraussetzung für eine präoperative Anfertigung passgenauer Implantate zum Ausgleich von Knochendefekten.

Various human skulls were scanned with a laser scanner. Impressive Landmarks of the skull were determined and tested to be comparable stored in a uniform coordinate system for subsequent 3-d reconstruction. The Rhinion, the Nasion, the Spina nasalis anterior, the Prosthion, and the Opisthokranion were found to be very qualified for the adjustment in the median plane. The frontal plane was defined by the Rhinion and the Spina nasalis anterior. The Mastoidealia, the Zygomaxillaria and the Orbitalia were used to align the skull in the horizontal plane. The qualification of the database as a fundamental part for the comparison of human skulls and for the discovery of similarities to patient skulls with bone defects is demonstrated by means of 2 clinical cases. A subsequent result is the application to manufacture fitting implants of biocompatible materials for covering huge side-overlapping bone destructions.

Noncontact three-dimensional laser measuring device for tracheoscopy.

Luminal dimension measurements are still an unsolved problem in endoscopy. The goal of our study was to develop a 3-dimensional (3-D) measuring device for endoscopic applications. For this purpose, a fiber probe projecting a ring of laser light (laser diode, 675 nm) was integrated in a position registration system. Software was developed for image analysis, distortion correction, and export of data for 3-D display. Experimental evaluation of measuring accuracy employing plastic tubes and 15 postmortem pig trachea preparations with artificial stenosis indicated a high level of method precision (Pearson's correlation coefficients, r = 0.99 for normal tracheal lumen and r = 0.97 for high-grade stenosis; p < .0001). Our clinical experience with the technique in 10 patients with tracheal stenosis revealed no side effects and encourages us to recommend this method for other endoscopic applications. The method enhances our 3-D grasp of endoscopically examined lesions.