Page 53 - DP Vol 19 No 2 HR_Neat

The posterior teeth
Fig 16: The chewing surfaces of the posterior teeth are larger and
have a naturally shaped chewing relief.
Fig 17: Thanks to the “Easy Centric” concept, the working cusps
of the upper posterior teeth can be easily brought to a centric
position.
Fig 18: During the try-in of the hybrid prosthesis, the space
required for teeth and framework is checked.
A good esthetic integration regardless of the selected occlusion
concept was paramount in the design of the VITA MFT posterior
teeth. The necks of the teeth are wider and have a natural buccal
arching (Figure 15).
The chewing surfaces are larger and have a very natural
chewing surface relief (Figure 16). The pre-abraded occlusal
surfaces of the posterior teeth of the mandible minimize the
horizontal shearing forces that are particularly damaging to
implants and thereby ensure the ideal static orientation of the
prosthesis.
The occlusal surface design of the VITA MFT line
is based on the innovative “Easy Centric” principle,
i.e. the surfaces are designed so that a perfect centric
position results almost automatically during setup
(Figure 17).
The basal cavity of the anterior teeth and posterior teeth
reduces the grinding effort, while simultaneously increasing the
contact area between the tooth and the base of the prosthesis,
and as a result, improves the bonding of the two materials when
the prosthesis is completed, in other words, fabricated in plastic.
Material properties
The plastic material used to manufacture VITA MFT has a
high proportion of highly cross-linked methacrylates (PMMA
pearls), which give the material excellent properties in respect to
mechanical stability and durability. The homogeneous material
structure and the lack of microporosities in the plastic inhibits
plaque formation. The excellent abrasion strength is very similar
to that of composite materials with a microfiller proportion.
In addition to the selection of the best suited tooth shape and
shade, the shade of the VITA MFT teeth can also be superbly
characterized with the veneering composite VITA VM LC (VITA
Zahnfabrik, Bad Säckingen, Germany) and also correspondingly
adapted to the patient’s age with a modified surface texture.
Probably the most important aspect for characterizing
prostheses, however, is the setup of the teeth, taking into account
individual irregularities and asymmetries in the anterior tooth
area. Equally important is the shaping of the base of the prosthesis,
i.e. the gingival section. In addition to functional requirements,
this meets esthetic requirements for imitating the natural model
to meet the highest standards.
Fig 19: Checking the space available for producing the
framework using the matrix.
Dental Practice i March-April 2023 i Vol 19 No 2 53