PubMed ID (PMID): 22930944Pages 9-21, Language: English, GermanNickenig, Hans-Joachim / Eitner, Stephan / Rothamel, Daniel / Wichmann, Manfred / Zöller, Joachim E.
The use of computer-aided surgical systems for dental implant bed preparation and implant placement results in an average precision within 1 mm of implant position and within 5 degrees of deviation for implant inclination. The accuracy of axis and implant position is significantly more precise with the three-dimensional surgical guide than with the free-hand method. The three-dimensional assessment of the restorative goal (radiopaque simulation of prosthesis with scanning template) allows virtual planning of implants, which enables optimized positioning of implants with surgical guide templates in oral surgery. If there is a clear indication for three-dimensional diagnostics, it should always be checked whether the data can be used as planning data for a surgical guide template, otherwise the chance for guided surgery remains unused. Since uncertainties still exist despite the use of a drilling template, it is recommended that the minimum safety distance from adjacent structures be maintained. The successful use of surgical guide templates requires comprehensive knowledge of and experience in using three-dimensional information for the virtual planning of implant position.
Keywords: dental implantation, image processing, computer-assisted, three-dimensional, treatment planning
PubMed ID (PMID): 22930945Pages 23-31, Language: English, GermanNemli, Secil Karakoca / Wolfart, Stefan / Reich, Sven
Purpose: The aim of this in-vitro study was to evaluate the accuracy of inLab and Cerec Connect software in simulating the maximum intercuspal contacts in comparison to the real situation on the respective gypsum casts.
Materials and Methods: Ten pairs of maxillary and mandibular casts were mounted in articulators in maximum intercuspal position. The contacts of the gypsum casts were marked and digital photographs of the mandibular casts were taken. Digital impressions of arches were made using two different software packages; inLab (Version 3.83) and Cerec Connect (Version 3.83) using the Cerec Acquisition Center. The intercuspal position of the teeth was captured by buccal images. Screenshots of the virtual casts showing the occlusal contacts were saved. The digital photographs of the contacts of the cast and the screenshots of the occlusal contacts were superimposed using an image processing program. The number of contacts of the virtual mandibular models that were identical with the contacts of the gypsum casts were determined and calculated as percentages in relation to the gypsum cast contacts, which were set as 100%. The null hypothesis tested was that the Cerec connect software delivers contacts that are closer to the real situation than contacts created with the inLab software.
Results: Cerec Connect showed a median percentage of 41.6% and Inlab a median percentage of 31.9%. The Wilcoxon test revealed statistically significant differences between the inLab software and Cerec Connect. Especially at the contra-lateral side of that side where the virtual buccal registration was done, the contacts showed the greatest deviations from the original.
Conclusion: Cerec Connect more precisely virtually simulated the real contacts than did inLab when scanning fullarch dentitions.
Keywords: inLab, Cerec Connect, buccal image method, maximum intercuspal position, occlusal contact, virtual occlusal contact
PubMed ID (PMID): 22930946Pages 35-44, Language: English, GermanHellstern, Flurina / Geibel, Margrit-Ann
Ziel: Es wurde die Umsetzung der Qualitätssicherung digitaler Zahnfilme im Klinikalltag untersucht. Die Ergebnisse sollten mit gesetzlichen Vorgaben und aktuellen Diskussionen von strahlenschutzverantwortlichen Einrichtungen debattiert werden.
Material und Methoden: 200 randomisierte digitale Zahnfilme aus der digitalen Datenbank des Departments für Zahnkeilkunde der Klinik für Mund-Kiefer-Gesichtschirurgie Ulm wurden auf verschiedene Aspekte der Bildqualität und auf die vom Gesetzgeber vorgeschriebenen Dokumentationen untersucht. Die Zahnfilme wurden an zwei digitalen intraoralen Röntgengeräten von medizinisch-technischen radiologischen Assistenten (MTRA) angefertigt. Gruppe A: Sirona Heliodent DS, 60kV, Brennfleckgröße: 0,7 mm; Gruppe B: KaVo Gendex 765DC, 65kV, Brennfleckgröße: 0,4 mm.
Ergebnisse: Die rechtfertigende Indikation war für 70,5 %, der erhobene Befund für 76,5 % dokumentiert. Beides wurde zu 14 % in der Software neben der Patientenakte dokumentiert. Die Dokumentationen des Namens des behandelnden Arztes und der MTRA, des Datums, des Patientennamen, der Abteilung, Röhrenspannung, des Röhrenstroms, der Belichtungszeit, Art der Aufnahme, Filmgröße, Abteilung und laufenden Nummer des Zahnfilmes waren zu 100 % vollständig. Eine Abteilung, die nach DIN ISO 9001:2008 zertifiziert ist, wies dagegen auch eine vollständige Dokumentation der rechtfertigenden Indikation und des Befundes auf. 83 % der Zahnfilme zeigten eine vollständige Abbildung der Zähne. Der Sichtbarkeitsbereich stimmte bei 85,7 % der Zahnfilme mit dem Bereich der Fragestellung überein. Hypo- beziehungsweise hypermetrische Abbildungen lagen bei 7-8,5 % vor.
Schlussfolgerung: Offensichtlich muss an der radiologischen Ausbildung und Fortbildung der Zahnärzte und des Personals, das zum Röntgen berechtigt ist, angesetzt werden, um einen hohen Qualitätsstandard zu erreichen. Die Einführung einer internen Qualitätssicherung nach dem Sozialgesetzbuch V, die seit 2010 verpflichtend ist, scheint sinnvoll zu sein.
Keywords: Qualitätsmanagement, Qualitätssicherung, digital, Radiologie, Zahnfilm, Strahlenschutz, Rechtfertigung, Dosis
PubMed ID (PMID): 22930948Pages 55-66, Language: English, GermanRonay, Valerie / Sahrmann, Philipp / Ender, Andreas / Bindl, Andreas / Schmidlin, Patrick R.
Hemisection of mandibular molars is a viable method of preserving periodontally or endodontically compromised teeth or roots. This paper describes a simple chairside CAD/CAM method of fabricating a cantilever crown for a hemisected molar. The technique is illustrated by a clinical case, which was treated according to this protocol and was followedup over 2.5 years. Given careful patient selection and strict recall intervals, the introduced method represents a conservative and cost-effective treatment modality for highquality ceramic reconstructions of root-resected teeth. In addition, other treatment options such as implantation or prosthesis, which would represent therapeutic and prosthetic endpoints, can be postponed.
Keywords: CAD/CAM, Cerec, hemisection, mandibular molar, reconstruction, periodontitis