Dentsply Sirona Biodent K+B Plus/OVS II Mode D'emploi page 20

Biodent® K+B Plus / OVS II
Cool off slowly, then grind and polish as usual . Fine toothed, hard-metal burs are very
suitable for grinding because of the greater hardness .
Extra Layers
lf, perhaps by an error in layering, the dentine shade looks too dark, reduce or rough en
the labial surface, moisten with a little monomer and overlay with enamel material . The
new material used for correction should have the same consistency as that applied
before . Colouring features can now be added or corrections made at the points of
contact . The transition from plastic to metal should be masked with fresh material .
Flask Method (Liquid N)
For veneers, ensure that the walls are thick enough (about 1 mm) .
The wax mould should be as close in shape and modelling to the final work as possible, so
that extensive grinding may not produce shade variations .
Mechanical retentions are essential in veneering . They should be placed whenever
possible in the interdental spaces .
Invest the prepared wax pattern so that the incisal edge rises at an angle of about 30° .
The whole labial surface and most of the proximal surfaces should be free of the invest-
ment plaster . After boiling-out, coat the plaster mould on both sides with Dentsply Sirona
Isolant .
Mixing
Mixing ratio of liquid to powder is 1:2 by weight . Pour liquid into the mixing vessel and
add enough powder to absorb all the monomer . Mix briefly . lf the paste is too thin, add
more powder until the paste no longer drips off the spatula . Now mix thoroughly for
15–30 seconds .
A rather higher proportion of liquid is used for the enamel material .
The materials are best mixed in the order in which they are to be used . Doughing time for
dentine and neck materials is about 6 minutes . The enamel paste, being thinner, can be
applied about 2 1 / minutes after mixing .
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A separate mixing vessel is supplied for each material . The matt surface of the lids can be
written on for identification purposes .
Layering
The materials are layered in the following order: dentine, neck (pre-cure for 10 minutes),
enamel (see Figs 3–5) .
For thick crowns, lay an extra wedge of transparent material – with or without an
admixture of enamel material – palatally on the incisal area (Fig . 3) . With veneers, the
metal frame must first be masked with opaque (see section "Opaque") .
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