Retention Load Values of Telescopic Crowns Made of Y-TZP and CoCr with Y-TZP Secondary Crowns: Impact of Different Taper Angles

Merk, Susanne; Wagner, Christina; Stock, Veronika; Schmidlin, Patrick R.; Roos, Malgorzata; Eichberger, Marlis und Stawarczyk, Bogna (2016): Retention Load Values of Telescopic Crowns Made of Y-TZP and CoCr with Y-TZP Secondary Crowns: Impact of Different Taper Angles. In: Materials, Bd. 9, Nr. 5, 354

Abstract

This study aimed to examine and compare the retention load values (RL) of different telescopic crown assemblies (Y-TZP and CoCr primary crowns with electroformed and Y-TZP secondary crowns each) with three different taper angles (0 degrees, 1 degrees and 2 degrees). Thirty Y-TZP primary crowns with electroformed gold copings (Z/G group) and Y-TZP secondary crowns (Z/Z group) and 30 CoCr primary crowns with electroformed gold copings (C/G group) and Y-TZP secondary crowns (C/Z group), each with taper angles of 0 degrees, 1 degrees and 2 degrees, were fabricated, respectively. With the exception of the electroformed gold copings, all specimens were Computer-Aided-Design/Computer-Aided-Manufacturing (CAD/CAM)-milled, then sintered and afterwards manually adapted. In order to stabilize the gold copings, they were fixed in a tertiary structure. The secondary crowns were constructed with a hook, which ensured self-alignment with an upper chain. Afterwards, 20 pull-off test cycles were performed in a universal testing machine under artificial saliva and after weighing the secondary crowns with a 5 kg object for 20 s. Data were analyzed by one-way and two-way Analysis of Variance (ANOVA). C/Z with 1 degrees showed higher (p = 0.009) RL than 0 degrees and 2 degrees tapers. C/G at 1 degrees also showed higher (p = 0.001) RL than at tapers of 0 degrees and 2 degrees. Z/G and C/G at 0 degrees showed lower RL than Z/Z and C/Z (p < 0.001). Primary crowns had no impact on the 0 degrees group. Z/G showed lower RL as compared to C/Z within the 1 degrees group (p = 0.007) and Z/Z in the 2 degrees group (p = 0.006). The primary crown material had no influence on RL. Electroformed copings showed lower RL. Further investigations for 1 degrees as well as for the long-term performance after thermomechanical aging are necessary.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 1996-1944
• Sprache: Englisch