Retention Load Values of Telescopic Crowns Made of Y-TZP and CoCr with Y-TZP Secondary Crowns: Impact of Different Taper Angles
AbstractThis 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°, 1° and 2°). 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°, 1° and 2°, 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° showed higher (p = 0.009) RL than 0° and 2° tapers. C/G at 1° also showed higher (p = 0.001) RL than at tapers of 0° and 2°. Z/G and C/G at 0° showed lower RL than Z/Z and C/Z (p < 0.001). Primary crowns had no impact on the 0° group. Z/G showed lower RL as compared to C/Z within the 1° group (p = 0.007) and Z/Z in the 2° group (p = 0.006). The primary crown material had no influence on RL. Electroformed copings showed lower RL. Further investigations for 1° as well as for the long-term performance after thermomechanical aging are necessary. View Full-Text
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Merk, S.; Wagner, C.; Stock, V.; Schmidlin, P.R.; Roos, M.; Eichberger, M.; Stawarczyk, B. Retention Load Values of Telescopic Crowns Made of Y-TZP and CoCr with Y-TZP Secondary Crowns: Impact of Different Taper Angles. Materials 2016, 9, 354.
Merk S, Wagner C, Stock V, Schmidlin PR, Roos M, Eichberger M, Stawarczyk B. Retention Load Values of Telescopic Crowns Made of Y-TZP and CoCr with Y-TZP Secondary Crowns: Impact of Different Taper Angles. Materials. 2016; 9(5):354.Chicago/Turabian Style
Merk, Susanne; Wagner, Christina; Stock, Veronika; Schmidlin, Patrick R.; Roos, Malgorzata; Eichberger, Marlis; 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." Materials 9, no. 5: 354.
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