Patient specific implants milled out of pure titanium showed a good outcome for more than 500 patients in the last decade. The vision of precise reconstruction and new bone generation is combined by the developments of the bioimplant-ruhr. A new animal model shows that the large defect of 4.5 by 5 cm(2) was bridged by new bone within 18 months.

The study analysed twelve anchorage systems based on micro implants in terms of their bio-mechanical properties and appraised their actual clinical effectiveness.The analysed micro implants had data provided by the manufacturers or extracted from articles published in specialised journals. The parameters taken into account were: material, surface treatment, head type, length, diameter, neck length, filleted self drilling or self tapping surface, applicable orthodontic forces, possibility of immediate loading, and device removal.Material Grade 5 titanium, titanium alloy (TiAl6V4), surgical steel; surfaces: smooth, sand-blasted and acid etched; head type: bracket, conic with button, round, hexagonal, button with cross cuts, double melted sphere; lengths: between 8.0 to14 mm; diameters: between 1.2 to 2.0 mms; neck lengths: inferior to 1.5 mm and superior to 2.0 mm; filleted portion: self tapping and/or self drilling; applicable orthodontic forces: up to 500 g, possibility of immediate loading, device removal, possibility to use in growing patients.The most widely used material was TiAl6V4; most of the surfaces were smooth; the most commonly used head type was the bracket; the most often produced length was the “short” one (8.0-9.9 mm), the most demanded diameter the “smaller” one (1.2-1.4 mms); six systems out of eleven had micro implants with “extra” and “standard” necks; only 3 systems out of eleven produced “non self drilling”devices; all the micro implants analysed were able to withstand orthodontic forces between 150 g and 350 g; all devices were suitable for “immediate loading”; all micro implants had to be removed; all micro implants could be used in growing patients.The comparative analysis showed that micro implants could be used as valid anchorage systems, if dental anchorage was insufficient either in qualitative terms (i.e. parodontal problems) or in quantitative terms (i.e. few dental elements remaining), and in all those situations of limited patient compliance.Le miniviti si stanno sempre più proponendo come sistemi di ancoraggio, grazie al loro semplice utilizzo clinico, al consenso estetico da parte del paziente e alla possibilità di superare alcuni limiti ortodontici.In questa analisi, dodici sistemi di ancoraggio costituiti da miniviti sono stati paragonati in base alle loro proprietà di design e strutturali, per valutarne la loro resa clinica.I dati relative alle miniscrews analizzate sono stati forniti dai produttori o ricavati da articoli pubblicati su riviste specialistiche. I parametri di comparazione scelti sono: materiali, tipologia della superficie,forme della testa, lunghezze, diametri, design del collo, superficie filettata self drilling o self-tapping, forze ortodontiche applicabili, rimovibilità del dispositivo, possibilità di utilizzo in pazienti in crescita.Materiali lega di titanio (TiAl6V4), titanio commercialmente puro, acciaio chirurgico; tipologia della superficie: liscia, sand-blasted e acid etched; testa: tipo bracket, conica con bottone, tonda, esagonale, a bottone, con tagli a croce, doppia sfera fusa; lunghezze: tra 8.0 e 14 mm; diametri: tra 1.2 e 2.0 mm; geometria collo: lunghezze inferiori a 1.5 mm e superiori a 2.0 mm; filettatura: self tapping e/o self drilling; forze ortodontiche applicabili: maggiori di 500 gr, possibilità di carico immediato: possibile; rimozione del dispositivo: possibile; possibilità di utilizzo in pazienti in crescita: possibile.Il material più utilizzato è la lega di Titanio TiAL6V4, la maggior parte delle superfici sono lisce, la forza della testa più utlizzata è quella tipo bracket, la lunghezza maggiormente proposta è compresa tra 8.0 e 9.9 mm, il diametro maggiormente prodotto è compreso tra 1.2 e 1.4 mm, sei sistemi su undici hanno miniviti con collo extra lungo e standard, solo 3 sistemi non sono self drilling, tutti i sistemi analizzati resistono a forze ortodontiche tra i 150 e i 350 gr. Tutti i sistemi analizzati possono essere immediatamente caricati e rimossi alla fine del loro utilizzo. Tutti i sistemi analizzati possono essere utilizzati su pazienti in crescita.Dall’analisi comparativa risulta che le miniviti possono essere utilizzate come valido sistema di ancoraggio se l’ancoraggio dentale è qualitativamente o quantitativamente insufficiente,e in tutte quelle situazioni di scarsa compliance del paziente.Les mini-vis se développent de plus en plus comme des systèmes d’ancrage, de par leur simple utilisation clinique, le consentement esthétique par les patients et la possibilité de dépasser quelques limites orthodontiques.Dans cette étude on a comparé douze systèmes d’ancrage par mini-vis sur la base de leurs propriétés structurelles et de design dans le but d’en évaluer la performance clinique.Les données concernant les mini-vis analysées ont été fournies par les fabricants ou bien tirées d’articles de la presse spécialisée. Les paramètres de comparaison choisis ont été les suivants : matières, typologie de surface, forme de la tête, longueurs, diamètres, design du cou, surface filetée auto-perceuse et auto-taraudeuse, forces orthodontiques d’application, possibilité de retirer le dispositif, possibilité d’utilisation chez des patients en croissance.Matières: alliage de titane (TiAl6V4), titane commercialement pur, acier chirurgical; typologie de la surface: lisse, rugueuse et mordançage acide; tête: type bracket, conique avec bouton, ronde, hexagonale, en forme de bouton, avec coupes en croix, double plot moulé; longueurs: entre 8.0 et 14 mm; diamètres: entre 1.2 et 2.0 mm; géométrie du cou: longueurs inférieures à 1.5 mm et supérieures à 2.0 mm; filetage: modalités auto-foreuse et/ou auto-perceuse; forces orthodontiques d’application: supérieures à 500 g ; possibilité de mise en charge immédiate: oui; dépose du dispositif: oui; possibilité d’utilisation chez des patients en croissance: oui.La matière la plus utilisée est l’alliage de titane TiAL6V4, la majorité des surfaces sont lisses, la force de la tête la plus utilisé est de type bracket; la longueur la plus proposée est comprise entre 8.0 et 9.9 mm; le diamètre le plus produit est compris entre 1.2 et 1.4 mm; six systèmes sur onze ont des mini-vis à collet extra-long et standard; seulement 3 systèmes ne sont pas self-drilling; tous les systèmes utilisés résistent à des forces orthodontiques entre 150 et 350 g. Tous les systèmes analysés peuvent être immédiatement mise en charge et retirés à la fin de leur utilisation. Tous les systèmes analysés peuvent être utilisés chez des patients en croissance.De l’analyse comparative il se dégage que les min-vis peuvent être utilisées comme un système valable d’ancrage au cas où l’ancrage dentaire serait qualitativement ou quantitativement insuffisant, et dans toutes les situations de mauvaise adhérence du patient.Los minitornillos se están afianzando, cada vez más, en sistemas de anclaje, por su fácil utilización clínica, el consentimiento estético por parte del paciente y la posibilidad de franquear algunos límites ortodóncicos.En este análisis, se compararon doce sistemas de anclaje por minitornillos, con arreglo a sus propiedades de diseño y estructurales, con el propósito de valorar y evaluar su prestación clínica.Los datos de los minitornillos analizados fueron proporcionados por los fabricantes o bien sacados de artículos publicados en revistas del sector. Los parámetros de comparación elegidos fueron los siguientes: materiales, tipología de superficie, formas de la cabeza, longitudes, diámetros, diseño del cuello, superficie autorroscante o autoperforante, fuerzas ortodóncicas aplicables, retirada del dispositivo, posibilidad de utilización en pacientes en crecimiento.Materiales Aleación de titanio (TiAl6V4), titanio comercialmente puro, acero quirúrgico; tipología de la superficie: lisa, rugosa y con grabado ácido; cabeza: tipo bracket, cónica con botón, redonda, hexagonal, de botón, con cortes en cruz, doble esfera bola fundida; longitudes: entre 8.0 y 14 mm; diámetros: entre 1.2 y 2.0 mm; geometría del cuello: longitudes inferiores a 1.5 mm y superiores a 2.0 mm; roscado: autorroscante y/o autoperforante; fuerzas ortodóncicas aplicables: superiores a 500 g, posibilidad de cargar inmediatamente: sí; retirada del dispositivo: sí; posibilidad de utilización en pacientes en crecimiento: sí.El material más utilizado es la aleación en titanio TiAL6V4, la gran parte de las superficies son lisas, la fuerza de la cabeza más utilizada es la de tipo bracket, el largo más propuesto varía entre 1.2 y 1.4 mm, el diámetro más producido se sitúa entre 1.2 y 1.4 mm, seis sistemas de once tienen minitornillos con cuello extra-largo y estándar; sólo 3 sistemas no son autorroscantes; todos los sistemas analizados aguantan fuerzas ortodóncicas entre 150 y 350 g. Todos los sistemas analizados pueden ser cargados inmediatamente y retirados al final de su utilización. Todos los sistemas analizados pueden ser empleados en pacientes en crecimiento.Del análisis comparativo se desprende de que los mnitornillos pueden ser utilizados como un sistema de anclaje válido en los casos en que el anclaje dentario no fuera cualicuantitavamente suficiente, y en todas las situaciones de mala adherencia del paciente.

This study of 169 consecutive individually prefabricated CAD/CAM titanium implants for cranioplasty between 1993 and 2000 yields comprehensive data of geometric, surgical, and medical aspects, and answers various questions of quality of life. The scheme for the classification of size and location of the defects is based on the precise CAD data of each implant. CAD/CAM-prefabricated titanium implants are of increased benefit in the neurocranium compared to the craniofacial area, including the forehead and the periorbital rims, which are more problematic with regard to primary fit and cosmetic result. Neurocranial protection and the consecutive improvement of the quality of life are more distinct in this group and come along with the highest benefit for patients with very large defects (>100 cm2 defect area). For the first time, the defect area could be determined so precisely with the CAD implant data and such a high number of extremely large consecutive cranioplasties could be evaluated.

AbstractTitan ist ein etabliertes Knochenersatzmaterial für die Versorgung komplexer Schädeldefekte mittels individuell geplanter CAD/CAM‐Implantate. Zur Verbesserung der durch Patientenkontrollstudien evaluierten thermischen und psychischen Belastungsfaktoren wurde in der vorliegenden Studie ein gradiertes Kompositmaterial aus Polymeren und Calciumphosphat bzw. Calciumcarbonat entwickelt. Biokompatibilitätsuntersuchungen auf Basis des ISO‐Standards 10993‐5 erlaubten zunächst die Auswahl geeigneter Materialien sowie nachfolgend die Feststellung der verbesserten pH‐Charakteristika der Kompositmaterialien gegenüber den reinen Polymeren. Für die geometrisch korrekte Herstellung der Implantate aus Kompositmaterialien wurden zwei unterschiedliche Verarbeitungsmethoden gewählt und kombiniert. Diese Implantate konnten bereits durch in‐vivo Versuche an einem eigens entwickelten Großtiermodell getestet werden und zeigten post mortem bei einem Nachbeobachtungszeitraum von zwei Monaten keine histologischen Reaktionen außerhalb der Norm und eine beginnende Knochenbildung. Klinisch ergaben sich bei den lebenden Schafen auch nach einem Zeitraum von bisher 11 Monaten keinerlei Komplikationen.

According to the desire of single-step skull bone resection and reconstruction the acquired CT data were not only used for the design of the individual implant but also for a robot-guided bone resection in an animal cadaver model. The results of three robot skull bone resections during 4 years showed a perspicuously improved precision combined with a dramatically reduced set-up time. As the evaluation of 166 patients with titanium skull implants showed thermal and psychic stress factors, a biodegradable composite material from polyesters, calcium phosphate and calcium carbonate for guided bone regeneration was developed. Skull implants made of this new bone substitution material showed promising results in animal experiments over a follow-up period from 2 to 11 months so far.

“Bochum Skull Implants” have been used in more than 300 patients so far. They are designed using reconstructed computed tomography (CT) data and produced out of pure titanium in a milling process. This report describes the clinical experience with the patients treated between 1994 and 2000. The defect region and its size as well as the outcome of the patients are analyzed. Considering the negative selection of patients, the advantages of the described procedure are impressive. The high precision and the easy handling of these implants make them useful, especially in complicated applications with very large defects, multiple previous operations and sometimes additional irradiations.

For the reconstruction of complex skull defects with individual prefabricated CAD/CAM-implants titanium is well established as a bone substitution material. In this study, a biodegradable composite material from polyesters and calcium phosphate was developed to reduce thermal and psychic stress factors, which were found in previous patient control studies. Biocompatibility tests based on the ISO-standard 10993-5 allowed the choice of suitable materials and showed much better pH-characteristics of the composites in comparison to the pure polymers. For the geometrically precise production of the implants, two different operating procedures (hot pressing and gas flushing) were combined. These implants have already been tested in in-vivo studies in sheep. Two months after implantation, post mortem there was no abnormal histological reaction but signs of beginning bone replacement. Nine months after operation there were no clinical complications in the living animals.

The question of precision of models in computer-assisted surgery was first discussed in the context of the use of computed tomography (CT) data for model fabrication by milling or stereolithography (STL) [Int. J. Oral Maxillofac. Surg. 24 (1995) 98, Dtsch. Z. Mund- Kiefer- Gesichts-Chir. 19 (1995) 221]. Since then, CT and other imaging procedures were fundamentally optimized. The physical prerequisites, however, are the same as 20 years before, i.e. a physical resolution of 0.5 mm principally limits the precision in CT and can only be optimized in little steps (CT) [Invest. Radiol. 29 (1994) 574, Int. J. Maxillofac. Surg. 24 (1995) 69, M. Wehmöller, H. Eufinger, A. Falk, W. Maβberg, E. Machtens, Reverse engineering methods for the determination of the precision of 3D helical CT data. In: Lemke, H.U., Inamura, K.U., Vannier, M.W. (Eds.), Computer Assisted Radiology and Surgery, CAR'97, Elsevier, Amsterdam (1997) p. 701]. Furthermore, biological conditions cannot be completely simulated in measurements performed with models since models cannot represent all the fine anatomical structures. Therefore, the interpretation of the images plays an important role in the further use in computer-assisted surgery.

For the reconstruction of complex skull defects with individual prefabricated CAD/CAM-implants titanium is well established as bone substitution material. The aim of our studies was to optimize a composite material from polyesters and calcium phosphate. Therefore two different operating procedures (hot pressing and gas-flushing) were combined. As a result the graded composition and porosity of the implants allow a spatial guided degradation progress and cell ingrowth. First biocompatibility tests in vitro with primary human osteoblasts showed a much better pH-characteristic and a better biocompatibility of the composites in comparison with the pure polymers. Degradation experiments in vitro confirmed the different expected degradation rates of the composite materials. As a next step in vivo experiments in ovine skulls are in progress.

The TICC (Tomography Image processing CAD-CAM) processing chain allows the supply of existing craniofacial defects with individually prefabricated implants based on helical CT data [1, 2]. In combination with individual templates single-step bone resection and reconstruction is available [3, 4, 5, 6]. New developments in navigation and robotics allowed a robot guided bone resection according to the preoperative planning with the CAD system [7, 8, 9, 10]. This study shows results of resection experiments oil ovine cadaver heads.

Die an der Ruhr-Universität Bochum entwickelte Verfahrenskette zur präoperativen Herstellung individueller Schädclimplantatc basiert auf Computertomographie (CT)-Daten des Patienten und bedient sich Computer Aided Design (CAD) und Computer Aided Manufacturing (CAM) [1,2, 3]. Dabei ist die Verfahrenskctte auf den Werkstoff Titan zugeschnitten und optimiert, erlaubt jedoch grundsätzlich auch die Verarbeitung anderer Materialien durch Fräsen oder in einer Hohlform [4]. Biodegradierbare Werkstoffe wie Polymere sind diesbezüglich von besonderem Interesse, da sie als Trägersubstanz für osteoinduktive Proteine eine Knochcnncubildung bei gleichzeitiger Degradation es Carriers ermöglichen [5, 6, 7].

Article EIN OPTIMIERTER BIODEGRADIERBARER WERKSTOFF FÜR DIE BEHANDLUNG GROSSFLÄCHIGER SCHÄDELDEFEKTE was published on January 1, 2001 in the journal Biomedical Engineering / Biomedizinische Technik (volume 46, issue s1).

A contour decomposition is proposed that allows partitioning and parameterizing contours. The decomposition firstly transforms the contour geometry into a local/global space by an iteration process that labels a selected segment and measures its amplitude. This space enables determining the location of high-curvature points, which however is a scale and context-dependent issue. From the local/global space an abstraction can be formed, from which geometric parameters such as curvature, smoothness, symmetry and edginess are derived. The decomposition output can explain a number of visual pop-out variances just by taking the difference across parameter values.