Purpose: This study compared the accuracy of cone beam computed tomography (CBCT) and medicalgrade CT in the context of evaluating the diagnostic value and accuracy of fiducial marker localization for reference marker-based guided surgery systems. Materials and Methods: Cadaver mandibles with attached radiopaque gutta-percha markers, as well as glass balls and composite cylinders of known dimensions, were measured manually with a highly accurate digital caliper. The objects were then scanned using a medical-grade CT scanner (Philips Brilliance 64) and five different CBCT scanners (Sirona Galileos, Morita 3D Accuitomo 80, Vatech PaX-Reve3D, 3M Imtech Iluma, and Planmeca ProMax 3D). The data were then imported into commercially available software, and measurements were made of the scanned markers and objects. CT and CBCT measurements were compared to each other and to the caliper measurements. Results: The difference between the CBCT measurements and the caliper measurements was larger than the difference between the CT measurements and the caliper measurements. Measurements of the cadaver mandible and the geometric reference markers were highly accurate with CT. The average absolute errors of the human mandible measurements were 0.03 mm for CT and 0.23 mm for CBCT. The measurement errors of the geometric objects based on CT ranged between 0.00 and 0.12 mm, compared to an error range between 0.00 and 2.17 mm with the CBCT scanners. Conclusions: CT provided the most accurate images in this study, closely followed by one CBCT of the five tested. Although there were differences in the distance measurements of the hard tissue of the human mandible between CT and CBCT, these differences may not be of clinical significance for most diagnostic purposes. The fiducial marker localization error caused by some CBCT scanners may be a problem for guided surgery systems.

Purpose: Two different stereolithographic surgical guide systems, NobelGuide (Nobel Biocare) and SimPlant (Materialise), were compared clinically, and the survival rates of the planned immediately loaded dental implants with prefabricated provisional restorations were evaluated. Materials and Methods: Patients were treated with implants using either the Materialise SimPlant system or the Nobel Biocare system. All implants were planned on cone beam computed tomography (CBCT) or CT-derived images. Mucosa-, bone-, or tooth-supported stereolithographic guides were produced using the two commercial systems. A provisional was placed immediately after implant insertion in all cases. Results: Fourteen patients were enrolled. Seventy-five implants were placed (34 with Materialise, 41 with Nobel Biocare) using stereolithographic surgical guides. All but one implant were loaded immediately with prefabricated provisionals. In all cases, implants were in place for a minimum of 12 months. No complications related to associated anatomy occurred. One implant failed, leading to a combined cumulative survival rate of 98.7%. There were no other intraoperative or postoperative complications. Implants placed by bone-supported guides had increased patient symptoms of postoperative swelling and discomfort. All provisionals were successful. Conclusions: Both types of stereolithographic surgical templates were sufficiently accurate in transferring the planned implant positions to the surgical field, allowing the placement of prefabricated provisionals. These technologies are most beneficial in patients in whom the simultaneous placement of multiple implants in combination with complex restorations is planned. Schlagwörter: guided surgery, stereolithography, surgical template, computed tomography, implant, immediate loading

Die 3-D-Diagnostik ist eine Bereicherung für viele klinische Fragestellungen und für komplexe Therapieplanungen. Eine Nutzung der DVT-Geräte sollte allerdings streng indikationsbezogen erfolgen und nicht zur generellen Substitution der klassischen 2DRöntgenaufnahmen führen. Da die DVT-Geräte hinsichtlich Genauigkeit, Bildqualität und Kontrastvermögen recht unterschiedlich sind, lohnt sich eine genaue Prüfung für die jeweilige Hauptindikation. Der Vorteil der geringeren Strahlenexposition im Vergleich zum CT bei ähnlicher diagnostischer Wertigkeit gibt dem DVT momentan den Vorzug bei anatomischen Fragestellungen. Die schlechtere Präzision des DVT in Bezug auf die Referenzmarkerdetektion von geführten Navigationssystemen ist allerdings verbesserungswürdig. Die betriebswirtschaftliche Darstellung des DVT ist aufgrund der hohen Gerätekosten, der notwendigen hohen Geräteauslastung und der sich schnell überholenden Technologie schwierig und muss individuell von jeder Praxis sorgfältig geprüft werden. Schlagwörter: Digitale Volumentomografie (DVT), Computertomografie (CT), Röntgen, Bohrschablone, Implantat, Referenzmarker

Purpose: The aim of this study was to evaluate the clinical response and safety of immediately loaded single-tooth implants placed in the posterior region of the maxilla and mandible. Materials and Methods: Single-tooth implants were placed in healed extraction sites in 20 adult patients. Temporary prefabricated acrylic resin crowns were prepared and adjusted. The crown occlusion was adjusted to obtain minimal contacts in maximum intercuspation. After 6 weeks a ceramometal or all-ceramic crown was cemented. Radiographic and clinical examinations were made at baseline and at 3, 6, and 12 months. Cortical bone response and peri-implant mucosal responses were evaluated. Results: The marginal bone level at the time of implant placement was preserved. The mean change in marginal bone level was 0.01 mm at 12 months. The mean Periotest value after 360 days was -4. The peri-implant mucosal adaptation to the anatomic form of the provisional crown resulted in a natural esthetic outcome, and a gain in papilla length was observed. One implant failure was recorded because of provisional luting cement impaction. Discussion: Clinical research has shown that immediate loading is a possible treatment modality. The immediate functional loading of implants placed in this study resulted in bone adaptation to loading. A satisfactory success rate with positive tissue responses was achieved. Conclusions: The results of this limited investigation indicated that immediate loading of unsplinted single-tooth implants in the posterior region may be a viable treatment option with an esthetic outcome.

A male patient presented for maxillary and mandibular complete-arch prostheses. A total of eight all-ceramic restorations, eight metal-ceramic crowns, and four metal-ceramic fixed partial dentures were placed. The restorations were examined for marginal integrity, anatomic form, surface, and color for a period of 12 months. All restorations were in function at the end of the evaluation period. There was no adverse event. No substantial difference between the all-ceramic onlays and the metal-ceramic crowns was apparent. The all-ceramic restorations exhibited the least plaque growth. Bleeding on probing was minimal at both restoration types. The marginal integrity of the all-ceramic restorations was considered to be nearly as precise as that of the metal-ceramic crowns.

Die zunehmende Forderung nach zahnfarbenen Restaurationsmaterialien hat zur Entwicklung neuer Presskeramiken geführt. Die Indikationen dieser Materialien umfassen neben Veneers und Inlays bzw. Onlays auch Teilkronen und Kronen. Moderne Keramiken weisen eine exzellente Biokompatibilität und Ästhetik auf. Zudem muss bei adhäsiv zementierten Keramikrestaurationen nur minimal eingegriffen und Zahnhartsubstanz geopfert werden. Durch den Einsatz moderner Adhäsivsysteme ließ sich die Langzeitprognose für vollkeramische Restaurationen deutlich verbessern. Entsprechend der erhöhten Zuverlässigkeit werden vollkeramische Versorgungen stetig mehr in der zahnärztlichen Routinebehandlung eingesetzt. Für die erfolgreiche Anwendung vollkeramischer Restaurationen wird das klinische Vorgehen detailliert beschrieben. Schlagwörter: Vollkeramik, adhäsives Zementieren, Inlay, Veneer, Kompositzement