QZ - Quintessenz Zahntechnik, 12/2021
Auf ein WortPages 1422-1423, Language: GermanPospiech, Peter
QZ - Quintessenz Zahntechnik, 9/2020
ErfahrungsberichtPages 1024-1030, Language: GermanPospiech, Peter
Bewährtes Verfahren zur Bestimmung der zentrischen KieferrelationStütz- beziehungsweise Pfeilwinkelregistrate sind eine seit über 100 Jahren bewährte Methode, den Unterkiefer in eine austarierte Position zu bringen. Dennoch schrecken noch viele Behandler davor zurück, sie anzuwenden. Der Beitrag beschreibt die Vorgehensweise und die Vorteile einer elektronischen Pfeilwinkelaufzeichnung.
Keywords: Stützstiftregistrat, Kieferrelation, Zentrikregistrat, Schreibplatte, Registrierschablone
Senioren-Zahnmedizin, 1/2020
Pages 49-50, Language: GermanPospiech, Peter
The International Journal of Prosthodontics, 1/2018
DOI: 10.11607/ijp.5368, PubMed ID (PMID): 29316570Pages 77-84, Language: EnglishWalter, Michael H. / Dreyhaupt, Jens / Hannak, Wolfgang / Wolfart, Stefan / Luthardt, Ralph G. / Stark, Helmut / Pospiech, Peter / Mundt, Torsten / Kern, Matthias / Böning, Klaus Walter / Wöstmann, Bernd / Scheller, Herbert / Jahn, Florentine / Reinhardt, Wilfried / Strub, Joerg / Marré, Birgit / Heydecke, Guido
Purpose: This study aimed to compare the long-term outcomes of two different nonimplant treatments in the bilateral shortened dental arch (SDA).
Materials and Methods: In a multicenter randomized controlled clinical trial, patients with complete molar loss in one arch were assigned to one of two different nonimplant treatments. In the partial removable dental prosthesis (PRDP) group, patients were provided with a distal-extension prosthesis retained with precision attachments. In the SDA group, patients were treated according to the SDA concept by preserving or restoring a premolar occlusion.
Results: Of the 152 treated patients, 82 reached the 10-year examination independent of their dental or prosthetic status. In the intention-to-treat analysis, the survival rates for tooth loss at 10 years were 0.44 (95% confidence interval [CI]: 0.30 to 0.56) in the PRDP group and 0.52 (95% CI: 0.37 to 0.65) in the SDA group. For tooth loss in the study arch, the survival rates were 0.67 (95% CI: 0.52 to 0.78) in the PRDP group and 0.60 (95% CI: 0.45 to 0.73) in the SDA group. The number of teeth lost was higher than expected. In a multivariate analysis using a multiple Cox regression model, the covariates age (unit: 1 year, Hazard Ratio [HR]: 1.033, P = .03) and DMFT value (unit: 1 tooth, HR: 1.121, P = .03) were significant for time to first tooth loss in the study arch.
Conclusion: The results suggest an overestimation of the influence of the prosthetic management of the bilateral SDA. In treatment decisions, patient preferences should be considered with appropriate weight.
Dentista, 1/2018
FokusPages 14-15, Language: GermanPospiech, Peter
Quintessenz Zahnmedizin, 9/2017
ProthetikPages 1031-1039, Language: GermanPospiech, Peter
Während festsitzender Zahnersatz schon seit Jahren vollständig bzw. teilweise digital hergestellt werden kann, steht der herausnehmbare Zahnersatz erst am Beginn dieser Entwicklung. In der Totalprothetik scheinen sich bereits gangbare und klinikreife Wege abzuzeichnen. Die hinsichtlich Konstruktion, Planung und Ausführung komplexeren Anforderungen der Teilprothese erlauben bislang allerdings keine rein digitalen Lösungen. Hier sind auch die Möglichkeiten einer rechnergestützten Planung noch nicht ausgeschöpft. Neue Materialkombinationen, Rapid-Prototyping-Verfahren und CAD-Konstruktionen gibt es zwar schon in Ansätzen, aber die Serienreife lässt noch auf sich warten.
Keywords: CAD/CAM, Teilprothese, Laserschmelzen, Einstückgerüstprothese, Monoframe-Prothese
International Journal of Computerized Dentistry, 4/2017
PubMed ID (PMID): 29292411Pages 363-375, Language: English, GermanRobben, Jan / Muallah, Jonas / Wesemann, Christian / Nowak, Roxana / Mah, James / Pospiech, Peter / Bumann, Axel
Plaster casts can be digitized with desktop scanners, intraoral scanners, and recently also with cone beam computed tomography (CBCT). The aim of this study was to investigate the accuracy of five different CBCT devices digitizing a plaster cast. A study cast serving as a patient was made using the double mix impression technique, and the impression was poured out with plaster. On the resulting plaster cast, arch length (AL), intermolar width (IMW), and intercanine width (ICW) were measured by a coordinate measuring machine (CMM) (Zeiss O-Inspect 422). The patient cast was then scanned by five CBCT devices - CS 9300, CS 9300 Select, CS 8100 3D (all Carestream), Promax 3D Mid (Planmeca), and Whitefox (Acteon) - in eight scan modes. For each CBCT device, 37 scans were performed. The resulting DICOM data were exported as stereolithographic (STL) data and linearly measured using Convince Premium 2012 (3Shape) software. All measurements were compared to the reference master values of the patient cast. The accuracy measurements showed significant differences among the CBCT devices. The highest accuracy was achieved by Whitefox (IMW: mean ± standard deviation (SD): 5.5 ± 5.7 µm) and CS 9300 (IMW: -15 ± 7.4 µm). Comparable results with less accuracy were shown by CS 8100 3D (IMW: -81.2 ± 7.4 µm) and CS 300 Select (IMW: -82.2 ± 6.6 µm). Significantly lower accuracy was shown by Promax 3D Mid (IMW: -126.1 ± 4.8 µm). Some CBCT devices are suitable for the digitization of plaster casts and show very good clinical accuracy. Dental offices equipped with CBCT devices could digitize plaster casts without the need for additional devices.
Keywords: CBCT devices, accuracy, indirect digitization, plaster cast, CAD/CAM, stereolithography
International Journal of Computerized Dentistry, 2/2017
PubMed ID (PMID): 28630956Pages 151-164, Language: English, GermanMuallah, Jonas / Wesemann, Christian / Nowak, Roxana / Robben, Jan / Mah, James / Pospiech, Peter / Bumann, Axel
The aim of this study was to compare the accuracy of six intraoral scanners as regards clinically relevant distances using a new method of evaluation. An additional objective was to compare intraoral scanners with the indirect digitization of model scanners. A resin master model was created by 3D printing and drilled in five places to reflect the following distances: intermolar width (IMW), intercanine width (ICW), and arch length (AL). To determine a gold standard, the distances were measured with a coordinate measuring instrument (Zeiss O-Inspect 422). The master model was scanned 37 times with the following intraoral scanners: Apollo DI (Sirona), CS 3500 (Carestream Dental), iTero (Cadent), PlanScan (Planmeca), Trios (3Shape), and True Definition (3M Espe), and indirectly digitized with the OrthoX Scan (Dentaurum). The digital models were then measured, and deviations from the gold standard calculated. Significant differences were found between the devices. Among the intraoral scanners, Trios and iTero showed the most accurate results, although CS 3500, True Definition, and Apollo DI achieved comparable results. PlanScan demonstrated the highest deviations from the gold standard, and presented a high standard deviation (SD). Direct digitization revealed comparable (and, in fact, slightly higher) accuracy than indirect digitization. Both indirect digitization and most of the intraoral scanners were therefore demonstrated to be suitable for use in the orthodontic office, with the exception of PlanScan, which did not meet the demands of individual orthodontic treatment.
Keywords: intraoral scanner, indirect digitization, full-arch scan, digital impression, CAD/CAM, accuracy
QZ - Quintessenz Zahntechnik, 2/2011
ExpertenfokusPages 162-164, Language: GermanPospiech, Peter
The International Journal of Oral & Maxillofacial Implants, 5/2010
PubMed ID (PMID): 20862414Pages 991-998, Language: EnglishNothdurft, Frank P. / Doppler, Klaus E. / Erdelt, Kurt J. / Knauber, Andreas W. / Pospiech, Peter R.
Purpose: The aim of the study was to evaluate the influence of artificial aging on the fracture behavior of straight and angulated zirconia implant abutments used in ZirDesign (Astra Tech) implant/tooth-supported fixed partial dentures (FPDs) in the maxilla.
Materials and Methods: Four different test groups (n = 8) representing anterior implant/tooth-supported FPDs were prepared. Groups 1 and 2 simulated a clinical situation with an ideal implant position (maxillary left central incisor) from a prosthetic point of view, which allowed for the use of a straight, prefabricated zirconia abutment. Groups 3 and 4 simulated a situation with a compromised implant position that required an angulated (20-degree) abutment. OsseoSpeed implants (4.5 3 13 mm, Astra Tech) as well as metal tooth analogs (maxillary right lateral incisor) with simulated periodontal mobility were mounted in polymethyl methacrylate. The FPDs (chromium-cobalt alloy) were cemented with glass ionomer. Groups 2 and 4 were thermomechanically loaded and subjected to static loading until failure. Statistical analysis of force data at the fracture site was performed using nonparametric tests.
Results: All samples survived thermomechanical loading. Artificial aging did not lead to a significant decrease in load-bearing capacity in either the straight abutments or the angulated abutments. The restorations that used angulated abutments exhibited higher fracture loads than the restorations with straight abutments (group 1: 209.13 ± 39.11 N; group 2: 233.63 ± 30.68 N; group 3: 324.62 ± 108.07 N; group 4: 361.75 ± 73.82 N). This difference in load-bearing performance was statistically significant, both with and without artificial aging. All abutment fractures occurred below the implant shoulder.
Conclusions: Compensation for angulated implant positions with an angulated zirconia abutment is possible without reducing the load-bearing capacity of implant/tooth-supported anterior FPDs.
Keywords: fatigue testing, fracture resistance, implant abutments, load-bearing capability, zirconia, zirconium dioxide