Ivoclar Vivadent IPS Eris for E2 - Manual (Page 26)

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Provide sprues in the direction of flow of the ceramic material. Pattern angled at 45–60 degrees
The attachment points of the sprue to the object and sprue former must be rounded and smooth. Avoid
sharp edges.
The dimensions of the sprues are:
Round profile, length 3 to 8 mm, Ø 2.5–3 mm /
8 gauge. When selecting the diameter of the sprue,
take the dimensions of the object into account. Select a
thinner sprue for delicate objects.
Sprueing of the object
a) Single crowns
For single crowns, depending on the size and volume of the
wax pattern, attach an axial sprue in the direction of flow of
the ceramic material (see page 27).
Use round wax profile Ø 2.5–3 mm / 8 gauge; length 3 to
max. 8 mm.
b) Bridges
For three unit bridges, attach a 2.5 to 3 mm round profile
axial wax sprue directly to the abutment teeth at an approx.
45 to 60° angle.
For extremely delicate wax patterns (e.g. lower incisors), an
additional axial sprue may be attached to the pontic to
enhance the stability of the investment material.
Version b: Only limited space is available
(reduced layering technique)
If only limited space is available, only the buccal and incisal
portion of the modelled framework is reduced in a targeted
fashion. The palatal-lingual portion should be pressed in its
full anatomic shape.
Reduce the wax-up by the space required for the layering
material to be applied after pressing. Observe the necessary
ratio of the framework thickness to the layering material
thickness, as described on page 23. IPS Connector ensures
that the minimum connector thickness between the pontic
and the bridge abutment is observed.
c) Wax-pattern sprue attachment
– Pattern angled at 45–60 degrees
– The distance between paper ring and object must be at
least 10 mm
– All sprue attachments are flared and smooth
The palatal-lingual portion should be pressed in its full anatomic shape.
Only the buccal and incisal portion of the modelled framework is reduced
The areas to be built up with layering material are clearly visible.