Figure 1: Full arch bridge on teeth and implants. The lateral movement is
guided by the canine.
Figure 2: After equilibration, the guidances are well shared on the whole
posterior occlusal faces on the masticating side.
Figure 3: The real mastication reveals an overguidance on the second bicuspid
Figure 4: The spline connection withstands lateral forces during mastication
in an optimal manner.
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Determining The Right Occlusal Scheme for Dental Implants
Marcel G. Le Gall, DDS
The lack of periodontal ligament around an osseointegrated implant has two important
consequences:1
• The absence of periodontal receptors reduce the proprioceptive and discriminative
capacity of the implants and hinders the mechanisms of avoidance generated by the
central nervous system in the presence of occlusal interference.
• The reduced mobility of the implant accentuates the effect of the overload
on the implant and peripheral bone.
These two factors complicate the manufacturing and occlusal adjustment of the implant
prosthesis which should insure optimal functional efficiency without transferring
to implant and bone interface the occlusal axial overload and excessive and/or uncontrolled
lateral forces.
To prevent these problems, the contacts and dental movements during mastication
and swallowing should be well known.2
However the classical occlusal concepts are only based on the patient’s lateral
and protrusive movements when asked to bite down. Thus, only incisors and/or canine
guidance are generally recorded, whereas during mastication the movement is inverted
and posterior contacts and guides can be revealed.
These mandibular kinetics and position discrepancies have a real importance on implant
prosthetics.
It is easy to demonstrate that only applying classical concepts ignores functional
interferences on implant prosthetics,3,4 a result of which is amplified
by the lack of mobility and the diminishing of deflecting reflexes on the implant.
The occlusal concept of practitioners must be modified in order to prevent such
problems.
1. During the prosthetic lab construction:
• The clinical recording of functional parameters and the functional setting
of articulators must be used to obtain an acceptable prosthesis for mastication.
2. At the clinical insertion of prosthesis:
• The clinical adjustment of the closure path must be accom plished to obtain
equal intensity and simultaneous contacts in intercuspal position (e.g. by using
an occlusal jig).
• Mastication on anterior and posterior prostheses must be simulated in order
to adjust and obtain a harmonious posterior guidance.
This objective of optimal functional equilibrium must modify the treatment planning
for implant placement, influencing the position, the orientation, and the number
of implants, under the prosthesis and the overall optimal implant bearing surface.
References
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