The Effect
Different Keeper Tray Materials Burn-out Incineration on Casting Investment
during Burn-out Procedures.
T.Kogiso, Y.Nakamura, Y.Ono, R.Kanbara,
K,Syoji, T,Masuda, K.Yoshihara, Y.Tanaka
Removable
Prosthodontics,
Abstract
Fabrication
methods of the magnetic attachment keeper component for restorative placement
have included casting or cementation procedures.(1-4) A cementation
method, previously reported, utilizes a ready-made plastic pattern for investment
burn-out and casting in a dental alloy. This technique does not subject the
keeper surfaces to casting procedure roughness or deformations. The keeper is
then directly cemented to the cast coping holder and is not subjected to
casting procedure heat distortion and is thus a recommended method.Cast keeper
coping housings require good casting accuracy as errors will prevent accurate
positioning and seating of the keeper to the housing. Laboratory or chairside
adjustment of these castings may be occasionally required .
A new prototype
keeper pattern using a keeper tray has been reported. The casting precision of
these prototype keeper patterns has been found to be superior to available
proprietary preformed keeper housing patterns .
The
purpose of the present study was to compare investment material use and casting
surface roughness for different samples of cast keeper housings from burn-out
to casting, to elucidate the casting problems and error onset and to
investigate casting defects different coping patterns.