Facading the overcoloured teeth with porcelain tehnology
The tehnology with integral porcelain assumes firstly a sufficient but an elastic
material too which should resist to the masticatory pressures without having
a metallic stand. There are special porcelain cases for the realization of integral
porcelain restaurations but there are firms too that are producing porcelain
of a special quality which may be used with or without a metallic stand. The
working model in the integral porcelain technology is a refractory blunt which
is a duplicate of the “master” model which stands out at temperatures
over 900 degrees from the porcelain owen.
In the case of the vital teeth with pigments we can successfully use the application
of the porcelain facet with 0,4-0,5 mm thickness. This is the reason why the
preparation does not imply the devitalization of the respective tooth. The facets
are applied onto the vestibular face. The preparation has as objective the obtainment
of one surface similar to the initial one but this one is situated at 0,4-0,5
mm in the depth of the smalt. There are many types of barbers which realize
either holes or fosses of pre-determined depth after which they are removed
from smalt through barbering until they reach the base of holes or fosses initially
made for guidance. The incisives edge will be shorten out and it will be replaced
in totality with a porcelain facet in this way the junction between the facet
and the stubby chases a trajectory which starts from the vestibular area at
the gums level, crosses on the faces chasing the gums papillae and ascending
towards the incisive until the half of the proximal faces. After that, it crosses
on the oral face at 1-2 mm far from the incisives edge. In order to hide in
an efficient manner the pigmentation, the part of the facet which comes into
contact with the tooth must contain an opaque layer which sould perfectly adhere
to the superior layers of the facets and should allow the adhesion on the stubby
with the help of the cementation resin. This opaque porcelain is applied as
a first layer on the unmanageable stubby and its being burnt. After that the
porcelain with the desired hue is being built and it’s applied at the
level of the incisives edge. The separation between the stubby and the facet
is done through the sectionning and the milling of the stubby until the facet
is close and after this process the rest of the refractory material which adhere
to the facet through the blasting with glass pearls which are not purifying
the porcelain surface is taken away.
At the beginning of the 90 years, the Japanese porcelain makers proposed another
method to hide the pigments in excess of the vital teeth with the help of the
facets that are integrally of porcelain through the usage of the complementary
colours technique usage. The principle of this technique stands in the appliance
of one facet with medium towards small transparency over the overpigmented stubby,
the facet having a more opened colour but on the transparency of the overpigmentation
it can be obtained an ideal hue.
In most of cases, the technology of porcelain integrality founds its application
only in the cases of vital teeth. The usage of porcelain facets in order to
hide the teeth that are overpigmented it’s an attitude that is not justified
because in this case the optimal variant is to realize some metal-porcelain
restaurations over one polished stubby that has a ‘doorstep’ (in
the tenacity order: fair ‘doorstep’, chanfren emphasized).