Objectives: To evaluate and compare an experimental surgical navigation system (ESNS) in implant placement accuracy to static planning and transfer systems. Material and Methods: Partially edentulous, surgical typodonts were used to simulate prosthetically-driven osteotomies in preclinical setting. After cbCT acquisition the DICOM files were used to reverse plan and fabricate surgical guides. Manual placement, three static guiding systems and ESNS were compared. Eight osteotomies per jaw were transferred to 10 typodonts in five series, resulting in 400 osteotomies by 3 operators, each modality. Lateral, vertical, total and angular deviations were measured and compared. Results: Computer-assisted systems were comparable and provided superior precision laterally and in angulation, but not vertically; implants placed in free-end positions were less accurate. Conclusions: All computer-aided methods showed less than 2 mm or 5 degrees error on average, which needs to be considered in clinical practice.

Objectives: To evaluate and compare an experimental surgical navigation system (ESNS) in implant placement accuracy to static planning and transfer systems. Material and Methods: Partially edentulous, surgical typodonts were used to simulate prosthetically-driven osteotomies in preclinical setting. After cbCT acquisition the DICOM files were used to reverse plan and fabricate surgical guides. Manual placement, three static guiding systems and ESNS were compared. Eight osteotomies per jaw were transferred to 10 typodonts in five series, resulting in 400 osteotomies by 3 operators, each modality. Lateral, vertical, total and angular deviations were measured and compared. Results: Computer-assisted systems were comparable and provided superior precision laterally and in angulation, but not vertically; implants placed in free-end positions were less accurate. Conclusions: All computer-aided methods showed less than 2 mm or 5 degrees error on average, which needs to be considered in clinical practice.

PURPPOSE: The objective of this research was to measure MVS between the central incisors and the posterior areas to evaluate whether computer designed guides can be used. MATERIALS AND METHODS: A total of 150 adult subjects (aged 22−78) were included. The population was further stratified by race, sex and Angle Classification. The examiner measured the maximum vertical space (MVS) at six specific sites. Measurements were repeated twice at each site. In addition overbite and ovejet were measured at the central incisor position. The pilot drill/guide appliance combination space requirement was tested with each category of MVS measurement. RESULTS: (i) there was a race effect, with African American having a greater maximum vertical space measurement than Caucasian and Asian respectively (P < 0.0001); (ii) there was a also gender effect, with males having a greater maximum vertical space measurement than females(P < 0.0001); (iii) there was an inverse association with overjet on central incisors and first premolars, with less overjet subjects having a greater maximum vertical space measurement (P < 0.05). We found that overall only 76% of the female cohort in our sample satisfied this space requirement of Nobel Guide (45mm) at the central incisor position. SUMMARY: Using the Nobel computer guided surgery minimum dimension requirement of 45mm, our findings suggest that first premolar or second molar implants could not be placed in our sample of dentulous patients, while a central incisor implant could be placed in 76%-100% of subjects depending on gender and race factors.

Com o avanço tecnológico, a associação da tomografia computadorizada (TC) e da prototipagem rápida (PR) trouxe um recurso valioso em Implantodontia, a cirurgia virtual guiada. Dentre as vantagens dessa técnica está a possibilidade da confecção da prótese dentária previamente ao ato cirúrgico, porém, para isso, ainda há muitas falhas a serem supridas. O objetivo deste estudo foi analisar a adaptação marginal de infraestruturas metálicas de próteses fixas sobre implantes pré-confeccionadas, por meio da cirurgia virtual guiada, em modelos experimentais. Foram confeccionados dez modelos de maxila totalmente desdentada, divididos em dois grupos aleatoriamente: cinco com as guias tomográfica e cirúrgica fixadas pela técnica convencional de cirurgia virtual guiada, denominado Grupo I (GI); cinco com as guias modificadas pela sua fixação ao sistema de encaixe oring de ortoimplantes, representando o grupo II (GII). Com os dados obtidos a partir de tomografia computadorizada foi realizado um planejamento virtual de cada grupo, para a instalação de quatro implantes nas regiões dos dentes 26, 13, 16 e 23 (D, B, A, C), instalados nesta sequência. De acordo com o planejado, foi confeccionada uma guia cirúrgica prototipada e uma infraestrutura metálica de prótese fixa, para cada grupo. A adaptação das estruturas metálicas foi avaliada sob dois aspectos: a passividade (passividade A e D) e desajuste vertical (Todos), usando um microscópio óptico. O desajuste vertical foi mensurado com todos os parafusos protéticos apertados com torque de 10Ncm. Os resultados mostraram que o método de aperto Todos, no GII (A - 0,130 mm; B - 0,110 mm; C - 0,200 mm; D - 0,100 mm), foi a situação mais próxima do aceitável clinicamente, pois somente o implante C apresentou valor maior que 0,150 mm. Tanto no GI quanto no GII, a passividade D obteve melhores resultados do que em passividade A. A partir destes resultados, concluiu-se que: na condição Todos, o GII apresentou melhor adaptação marginal das infraestruturas metálicas quando comparado ao GI; o uso do ortoimplante associado ao sistema de retenção oring auxiliou na estabilidade das guias tomográfica e cirúrgica do GII; infraestruturas metálicas de próteses fixas sobre implantes pré-confeccionadas por meio da cirurgia virtual guiada não alcançaram adaptação marginal aceitável. / The combination of computed tomography (CT) and rapid prototyping (RP) has brought a valuable resource in dental implants, guided virtual surgery. Among the advantages of this technique is the possibility of manufacturing the dental prosthesis prior to surgery, but for this, there are still many failures to be addressed. The objective of this study was to analyze the marginal adaptation of prefabricated metal frameworks of fixed implant prostheses placement by virtual guided surgery in experimental models. Ten models of edentulous maxilla were randomly divided into two groups of five: GI and GII. The tomography guide and prototyping surgery in GI group were installed by conventional technique whereas in GII group they were retained by an orthodontic implants modified with o´ring system. From data obtained by CT, the virtual planning was accomplished for placement of four implants on the region of teeth 26, 13, 16, 23 (D, B, A, C) to be installed on this sequence. A prototyped surgical guide was manufactured for each group from the virtual planning and the metal framework was made using this guide. Four implants were installed in each model according to the planning by guided virtual surgery technique. The marginal adaptation of metal frameworks was evaluated from two aspects: passivity (passivity A and D) and vertical misfit (All). The level of vertical misfit frameworks was measured while all retaining screws tightened with torque 10Ncm. We used a standard method of tightening the screws, DBAC, so that the structure is fixed in the same sequence of installation of the implant. The results showed that the method of tightening of all the screws GII (A-0.130 mm, B-0.110 mm; C-0.200 mm and D-0.100 mm) was the most close to clinically acceptable, since only the implant C vertically, showed values higher than 0.150 mm. Both GI and GII, the passivity method D yielded better results than in passivity A. From the results it is concluded that, provided All the GII showed better marginal adaptation of metal framework when compared to GI, the use of the modified orthodontic implant, helped the stability of surgical guides and tomography of the GII; metal framework fixed prosthesis on implants, prefabricated through guided virtual surgery, did not reach acceptable marginal fit.

Com o avanço tecnológico, a associação da tomografia computadorizada (TC) e da prototipagem rápida (PR) trouxe um recurso valioso em Implantodontia, a cirurgia virtual guiada. Dentre as vantagens dessa técnica está a possibilidade da confecção da prótese dentária previamente ao ato cirúrgico, porém, para isso, ainda há muitas falhas a serem supridas. O objetivo deste estudo foi analisar a adaptação marginal de infraestruturas metálicas de próteses fixas sobre implantes pré-confeccionadas, por meio da cirurgia virtual guiada, em modelos experimentais. Foram confeccionados dez modelos de maxila totalmente desdentada, divididos em dois grupos aleatoriamente: cinco com as guias tomográfica e cirúrgica fixadas pela técnica convencional de cirurgia virtual guiada, denominado Grupo I (GI); cinco com as guias modificadas pela sua fixação ao sistema de encaixe oring de ortoimplantes, representando o grupo II (GII). Com os dados obtidos a partir de tomografia computadorizada foi realizado um planejamento virtual de cada grupo, para a instalação de quatro implantes nas regiões dos dentes 26, 13, 16 e 23 (D, B, A, C), instalados nesta sequência. De acordo com o planejado, foi confeccionada uma guia cirúrgica prototipada e uma infraestrutura metálica de prótese fixa, para cada grupo. A adaptação das estruturas metálicas foi avaliada sob dois aspectos: a passividade (passividade A e D) e desajuste vertical (Todos), usando um microscópio óptico. O desajuste vertical foi mensurado com todos os parafusos protéticos apertados com torque de 10Ncm. Os resultados mostraram que o método de aperto Todos, no GII (A - 0,130 mm; B - 0,110 mm; C - 0,200 mm; D - 0,100 mm), foi a situação mais próxima do aceitável clinicamente, pois somente o implante C apresentou valor maior que 0,150 mm. Tanto no GI quanto no GII, a passividade D obteve melhores resultados do que em passividade A. A partir destes resultados, concluiu-se que: na condição Todos, o GII apresentou melhor adaptação marginal das infraestruturas metálicas quando comparado ao GI; o uso do ortoimplante associado ao sistema de retenção oring auxiliou na estabilidade das guias tomográfica e cirúrgica do GII; infraestruturas metálicas de próteses fixas sobre implantes pré-confeccionadas por meio da cirurgia virtual guiada não alcançaram adaptação marginal aceitável. / The combination of computed tomography (CT) and rapid prototyping (RP) has brought a valuable resource in dental implants, guided virtual surgery. Among the advantages of this technique is the possibility of manufacturing the dental prosthesis prior to surgery, but for this, there are still many failures to be addressed. The objective of this study was to analyze the marginal adaptation of prefabricated metal frameworks of fixed implant prostheses placement by virtual guided surgery in experimental models. Ten models of edentulous maxilla were randomly divided into two groups of five: GI and GII. The tomography guide and prototyping surgery in GI group were installed by conventional technique whereas in GII group they were retained by an orthodontic implants modified with o´ring system. From data obtained by CT, the virtual planning was accomplished for placement of four implants on the region of teeth 26, 13, 16, 23 (D, B, A, C) to be installed on this sequence. A prototyped surgical guide was manufactured for each group from the virtual planning and the metal framework was made using this guide. Four implants were installed in each model according to the planning by guided virtual surgery technique. The marginal adaptation of metal frameworks was evaluated from two aspects: passivity (passivity A and D) and vertical misfit (All). The level of vertical misfit frameworks was measured while all retaining screws tightened with torque 10Ncm. We used a standard method of tightening the screws, DBAC, so that the structure is fixed in the same sequence of installation of the implant. The results showed that the method of tightening of all the screws GII (A-0.130 mm, B-0.110 mm; C-0.200 mm and D-0.100 mm) was the most close to clinically acceptable, since only the implant C vertically, showed values higher than 0.150 mm. Both GI and GII, the passivity method D yielded better results than in passivity A. From the results it is concluded that, provided All the GII showed better marginal adaptation of metal framework when compared to GI, the use of the modified orthodontic implant, helped the stability of surgical guides and tomography of the GII; metal framework fixed prosthesis on implants, prefabricated through guided virtual surgery, did not reach acceptable marginal fit.

Frameless neuronavigational systems are a recent novelty for a precise approach to intracerebral tumours in open surgery. In this study 66 patients with a variety of intracranial tumours in various locations underwent surgical resection with neuronavigational guidance. Two different neuronavigational systems – the arm- and pointer-based ISG viewing wand and the miroscope-based MKM system – were compared for four different indications. Neuronavigation was used (a) in multiple tumours, e. g. brain metastases, (b) in solitary cortical or subcortical tumours located in eloquent brain areas, e. g. motor cortex or speech region, (c) in deep-situated brain tumours, including brain stem neoplasms, and (d) in infiltratively growing tumours to define the borders of the lesion. Using taped skin markers (MKM system) and a surface-fit algorithm (viewing wand) for registration, an accuracy of 1 to 2 mm deviation was achieved, which was sufficient for removal of all of the intracranial neoplasms investigated. Both systems proved to be safe and useful surgical tools regardless of the patient`s age, positioning of the patient during surgery or the location of the lesion. When these two systems were compared, the viewing wand was found to be preferable for resection of multiple brain tumours located in distant operative sides and solitary tumours in eloquent brain areas; this was because of the wide range of movement of the pointing device and the possibility of 3D reconstruction of the brain surface. As the MKM system provided the option of stereotactical guidance during the operative procedure, it was found to be superior in approaching small and deep-situated lesions. In certain cases brain shifting due to early drainage of the CSF led to minor underestimation of the real depth. For the precise definement of tumour borders of intraparenchymal neoplasms both system were equally suitable. However, intrusion of brain parenchyma into the resection cavity led to minor overestimation of the real tumour size in certain large intraparenchymal tumours. / Rahmenfreie Neuronavigationssysteme stellen eine Neuerung in der offenen operativen Behandlung intrazerebraler Tumoren dar. In dieser Studie wurden 66 Patienten mit verschiedenen intrakraniellen Tumoren in unterschiedlichen Lokalisationen mit Hilfe der Neuronavigation operiert. Hierbei wurden zwei verschiedene Navigationssysteme – ein Arm- und Pointer-basierendes System (ISG Viewing Wand) und ein Mikroskop-basierendes System (MKM) – für vier verschiedene Indikationen miteinander verglichen. Die Neuronavigation wurde verwendet (a) bei multiplen Tumoren, wie z.B. Hirnmetastasen, (b) bei solitären kortikalen oder subkortikalen Prozessen in eloquenten Hirnarealen, wie z.B. Motorkortex oder Sprachregion, (c) bei tiefgelegenen Hirntumoren einschließlich Hirnstammtumoren und (d) bei infiltrativ wachsenden Tumoren zur Bestimmung der Tumorgrenzen. Die Verwendung von Hautklebemarkern (MKM-System) und eines Oberflächen-Anpassungsalgorithmus (Viewing Wand) zur Registrierung war mit einer Genauigkeit von 1 bis 2 mm Abweichung für die operative Entfernung aller intrakraniellen Tumoren ausreichend. Beide Systeme bestätigten sich als sichere und geeignete chirurgische Hilfsmittel unabhängig vom Alter der Patienten, der Lagerung des Patienten unter dem chirurgischen Eingriff und der Lokalisation der Raumforderung. Im Systemvergleich zeigte die Viewing Wand durch einen weiten Bewegungsraum des Pointers und der Möglichkeit einer dreidimensionalen Rekonstruktion der Hirnoberfläche Vorteile in der Entfernung von multiplen, in entfernten Hirnregionen gelegenen Tumoren sowie von solitären Prozessen in eloquenter Lokalisation. Das MKM-System war durch die Bereitstellung einer stereotaktischen Führung während des operativen Eingriffes in der Ansteuerung kleiner tiefgelegener Prozesse zu bevorzugen. Eine frühzeitige Liquordrainage führte zu einem brain shifting mit einer diskreten Unterschätzung der wirklichen Tiefe. Für eine genaue Festlegung der Tumorgrenzen von intraparenchymalen Tumoren waren beide Systeme vergleichbar geeignet. Das Relabieren von Hirngewebe in die Resektionshöhle führte jedoch in einigen Fällen von großen intraparenchymalen Tumoren bei beiden Systemen zu einer geringen Überschätzung der wirklichen Tumorgrenzen. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Frameless neuronavigational systems are a recent novelty for a precise approach to intracerebral tumours in open surgery. In this study 66 patients with a variety of intracranial tumours in various locations underwent surgical resection with neuronavigational guidance. Two different neuronavigational systems – the arm- and pointer-based ISG viewing wand and the miroscope-based MKM system – were compared for four different indications. Neuronavigation was used (a) in multiple tumours, e. g. brain metastases, (b) in solitary cortical or subcortical tumours located in eloquent brain areas, e. g. motor cortex or speech region, (c) in deep-situated brain tumours, including brain stem neoplasms, and (d) in infiltratively growing tumours to define the borders of the lesion. Using taped skin markers (MKM system) and a surface-fit algorithm (viewing wand) for registration, an accuracy of 1 to 2 mm deviation was achieved, which was sufficient for removal of all of the intracranial neoplasms investigated. Both systems proved to be safe and useful surgical tools regardless of the patient`s age, positioning of the patient during surgery or the location of the lesion. When these two systems were compared, the viewing wand was found to be preferable for resection of multiple brain tumours located in distant operative sides and solitary tumours in eloquent brain areas; this was because of the wide range of movement of the pointing device and the possibility of 3D reconstruction of the brain surface. As the MKM system provided the option of stereotactical guidance during the operative procedure, it was found to be superior in approaching small and deep-situated lesions. In certain cases brain shifting due to early drainage of the CSF led to minor underestimation of the real depth. For the precise definement of tumour borders of intraparenchymal neoplasms both system were equally suitable. However, intrusion of brain parenchyma into the resection cavity led to minor overestimation of the real tumour size in certain large intraparenchymal tumours. / Rahmenfreie Neuronavigationssysteme stellen eine Neuerung in der offenen operativen Behandlung intrazerebraler Tumoren dar. In dieser Studie wurden 66 Patienten mit verschiedenen intrakraniellen Tumoren in unterschiedlichen Lokalisationen mit Hilfe der Neuronavigation operiert. Hierbei wurden zwei verschiedene Navigationssysteme – ein Arm- und Pointer-basierendes System (ISG Viewing Wand) und ein Mikroskop-basierendes System (MKM) – für vier verschiedene Indikationen miteinander verglichen. Die Neuronavigation wurde verwendet (a) bei multiplen Tumoren, wie z.B. Hirnmetastasen, (b) bei solitären kortikalen oder subkortikalen Prozessen in eloquenten Hirnarealen, wie z.B. Motorkortex oder Sprachregion, (c) bei tiefgelegenen Hirntumoren einschließlich Hirnstammtumoren und (d) bei infiltrativ wachsenden Tumoren zur Bestimmung der Tumorgrenzen. Die Verwendung von Hautklebemarkern (MKM-System) und eines Oberflächen-Anpassungsalgorithmus (Viewing Wand) zur Registrierung war mit einer Genauigkeit von 1 bis 2 mm Abweichung für die operative Entfernung aller intrakraniellen Tumoren ausreichend. Beide Systeme bestätigten sich als sichere und geeignete chirurgische Hilfsmittel unabhängig vom Alter der Patienten, der Lagerung des Patienten unter dem chirurgischen Eingriff und der Lokalisation der Raumforderung. Im Systemvergleich zeigte die Viewing Wand durch einen weiten Bewegungsraum des Pointers und der Möglichkeit einer dreidimensionalen Rekonstruktion der Hirnoberfläche Vorteile in der Entfernung von multiplen, in entfernten Hirnregionen gelegenen Tumoren sowie von solitären Prozessen in eloquenter Lokalisation. Das MKM-System war durch die Bereitstellung einer stereotaktischen Führung während des operativen Eingriffes in der Ansteuerung kleiner tiefgelegener Prozesse zu bevorzugen. Eine frühzeitige Liquordrainage führte zu einem brain shifting mit einer diskreten Unterschätzung der wirklichen Tiefe. Für eine genaue Festlegung der Tumorgrenzen von intraparenchymalen Tumoren waren beide Systeme vergleichbar geeignet. Das Relabieren von Hirngewebe in die Resektionshöhle führte jedoch in einigen Fällen von großen intraparenchymalen Tumoren bei beiden Systemen zu einer geringen Überschätzung der wirklichen Tumorgrenzen. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.