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CLINICALFEATURE
Figure 3a Destruction of the supporting Tissues
b: guiding plane
h: food impaction
g: fulcrum
f: periodontal desease
movements causes more resorption and more resorption
Conduct automatically to more movement.
The cost of the dental laboratory is relatively expensive,
especially when related to precision mechanism. Repairs are
time-consuming and are charged for high fees by the dental
technician.
Another consideration is that these appliances are involving
crowns for the abutment teeth. For the senior patients, this
could be a financial burden, and often is not recommended for
anatomical or periodontal considerations .
Figure 3b Posterior bone resorption
acting as Stress
absorbing device. 7
Rationale of the
Concept
In opposition with
the classic concept
of stress breaking
based on the Lever
Type I, the SAF is
based on the Lever
type III, determined
by a back action
(Figure 7b). In this
case the occlusal
forces are acting on
the mesial end of
the Saddle and are absorbed by the frame (Figure 8).
The component of the occlusal forces are working vertically
parallel to the teeth axis. Moreover the spring resilience effect
is relocating automatically the RPD on is initial place. In this
way avoiding soars and accelerates bone loose. (Figure 9) The
realization of a separation between the basis (saddle) and the
supporting teeth abutment is forbidding the tilting movement on
the distal abutment teeth.
The saddle is in fact relied to the major connector on his distal
part, allowing on the mesial segment a freedom of movement
on the vertical and lateral direction. The resilience of the frame
is absorbing the occlusal trauma. (Figures 10 & 10b)
4. Maintaining a balanced occlusal contact and preserving in
this way the life –span of the remaining natural teeth.
The Stress Absorbing Frame (SAF)
In order to overrule this problematic situation it is
recommended to design of a RPD with a Frame which is also
Discussion
The classic stress-breaking concept was widely analyzed a
discussed in the literature 8 , but very few authors paid attention
Figure 4 Fixed prosthodontics and removable semiprecision
lower denture
Figure 5a Precision attachment Hinge Axis type
Figure 5b Precision
attachment Hinge Axis type
Dental Asia • May / June 2008
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