Impression material accuracy for palatal orthodontic miniscrews
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ORIGINAL ARTICLE
Impression material accuracy for palatal orthodontic miniscrews Natalie Schenz1 · Vincent Schwarz2 · Romed Hörmann3 · Adriano G. Crismani1 Received: 16 December 2019 / Accepted: 17 May 2020 © The Author(s) 2020
Abstract Purpose This study investigates the accuracy of abutment transfer with current impression materials and provides a concise overview, including other relevant factors, in order to enable clinicians to make an informed decision about the optimal impression for this treatment procedure. Methods In all, 96 impressions of a cadaver head with two orthodontic miniscrews in place were taken with four common impression materials by two observers and using two methods of application. After pouring with a standard type IV stone and abutment transfer, all models and the upper jaw (which had been separated from the head) were scanned in a standard model scanner (Zirkonzahn® [Zirkohnzahn GmbH, Gais, Italy] S600 ARTI) and evaluated using a computer-aided design (CAD) program (GOM-Inspect [Gesellschaft für optische Messtechnik m.b.H., Braunschweig, Germany]). The deviations were measured at six points per screw and statistically evaluated with SPSS® (IBM, Chicago, IL, USA). Results Optimal values were obtained with biphasic polyvinylsiloxane, while monophasic polyvinylsiloxane, alginate and polyether also resulted in acceptable accuracy. Observer experience showed no effect and the method of application had only a minor effect on accuracy. Conclusions Within the limitations of this study, it seems that all impression materials are suitable for miniscrew abutment transfer, provided that methods of intraoral adaptation of the orthodontic appliance can be employed. If higher accuracy is needed or for clinicians with less experienced, a biphasic polyvinylsiloxane impression with the putty-wash technique should be used as this combination reduces setting time. The most cost-effective version, alginate, can be used if the consequences of greater deviations can be handled. Caution is advised with polyether if undercuts are present.
Keywords Polyvinylsiloxane · Alginate · Polyether · Temporary anchorage devices · Orthodontic anchorage procedures
Dr. Natalie Schenz
[email protected] Dr. Vincent Schwarz [email protected] Romed Hörmann [email protected] Univ.-Prof. Dr. Adriano G. Crismani [email protected] 1
University Hospital for Orthodontics, Medical University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria
2
Department of Cranio-Maxillofacial Surgery, Faculty of Medicine of the Kepler University Linz, Krankenhausstraße 9, 4020 Linz, Austria
3
Division of Functional and Clinical Anatomy, Medical University of Innsbruck, Müllerstraße 59, 6020 Innsbruck, Austria
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N. Schenz et al.
Genauigkeit von Abformmaterialien für palatinale kieferorthopädische Minischrauben Zusammenfassung Zielsetzung Die vorliegende Studie untersucht die Genauigkeit von Abformmaterialien für den Abutment-Transfer und versucht, einen kompakten Überblick über relevante Faktor
