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Distortion of Three‐Unit Implant Frameworks During Casting, Soldering, and Simulated Porcelain Firings
Author(s) -
Zervas Photios J.,
Papazoglou Efstratios,
Beck F. Michael,
Carr Alan B.
Publication year - 1999
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/j.1532-849x.1999.tb00032.x
Subject(s) - soldering , materials science , casting , distortion (music) , composite material , wave soldering , metallurgy , ceramic , amplifier , optoelectronics , cmos
Purpose The aim of this study was to assess distortion inherent in casting, soldering, and simulated porcelain firings of screw‐retained, implant‐supported three‐unit fixed partial dentures (FPDs). Materials and Methods Ten wax patterns were fabricated on a die‐stone cast containing two implants, 20 mm apart from center to center. Five specimens were cast in a high‐palladium alloy, exposed to simulated porcelain firings, sectioned, and then soldered with low‐fusing solder. Five specimens were cast, sectioned, soldered with high‐fusing solder, and then exposed to simulated porcelain firings. For each specimen, two horizontal and six vertical distances between appropriately scribed reference points were measured with a traveling microscope. Comparisons were made among the various measurements taken after wax‐pattern fabrication, casting, high‐ and low‐fusing soldering, and each porcelain firing. Data were analyzed using a repeated‐measures factorial ANOVA (α= 0.05). Results Significant difference was detected in the amount of horizontal distortion during casting (53 ± 24 μm) and high‐fusing soldering (−49 ± 50 μm), as well as in the amount of horizontal distortion during high‐fusing soldering (−49 ± 50 μm) and low‐fusing soldering (17 ± 26 μm). However, no clinically significant difference was found in the amount of horizontal distortion during casting, low‐fusing, and high‐fusing soldering. The greatest amount of distortion during the simulated porcelain firings took place during the oxidizing cycle. Conclusions Soldering did not improve the casting misfit of a three‐unit implant‐retained FPD model. Metal‐ceramic implant frameworks should be oxidized before intraoral fit evaluation.