Physiology of the bone

         Physiological and bio-mechanical foundation of basal implantology.

 

         The basilar bone, the teeth, the periodontium and the temporomandibular articulation are the structural axis of the stomatognathic system. The masticatory mechanism is highly adaptive to changing functional patterns and retains high degree of regenerative capability.

 

         Bone morphology and adaptive mechanisms*

 

         Consistent with the physiologic conservation of energy, bone structure is maintained at minimum level to perform optimal metabolic and structural functions. The skeletal support of the stomatognathic system is classic example of “form following function”. However, structural support is not the most critical function of the skeletal system; its most important role is to serve as a physiologic reservoir for calcium. Under conditions of negative calcium balance, bone is lost within the trabecular network and along the inner surface of the peripheral cortex. Systemic demand for calcium exceeding that available from normal dietary absorption result in bone resorption from the least structurally essential areas of the skeleton, i.e. the endosteal bone surfaces and the trabecular bone. Since calcium metabolism is a critical life support function, serum calcium levels must be maintained despite damage to structural support.

 

         Structural and metabolic fractions*.

 

As growing bones approach adult dimensions, characteristic pattern of primary and secondary bone formation(modeling and remodeling) delineate the functional morphology of the skeleton. The outer cortex and lamina dura are structurally conserved osseous tissue, while the inner cortex and all the trabecular bone(alveolar bone is part of that bone) are metabolically liable.

Under conditions of sustained negative calcium balance or adverse mechanical demands(overload or disuse) the endosteal portions of the cortex and all internal trabecular bone are methabolically liable.

*(W.Eugene Roberts, William Hohlt, Gordon Arbuckle, The Supporting Structures and Dental Adaptation, Science and Practice of Occlusion.)

 

         The cardinal principle of bone structure is maximal strength with minimum mass, what means, that the bone is available only where it is necessary.

         In the event of teeth loss, the alveolar bone loses its functional stimulus, what leads to the resorption of already unnecessary alveolar process. The edentulism causes overall decrease of the functional stimulus in the stomatognathic system and along with the hormonal influences causes decrease of muscle and bone mass as a whole.

It is important, that decrease of the bone mass is at the expense of the metabolically active parts of the jaw bones. The structural parts are relatively metabolically resistant.

 

         The fundamental difference, between the basal and conventional dental implantology, is the bone areas(fractions), what are being utilized in order to harbor the implants.

In the conventional dental implantology, the implants are being placed in the crestal bone, i.e. metabolically active, hence structurally unstable bone fraction.

The basal implantology utilizes the basilar(basal) bone segments, which are metabolically resistant and because of that structurally stable.

In the lower jaw such structurally stable areas are the basis and the symphisis of the mandible**.

In the upper jaw metabolically, and hence resorption stable areas are: the nasal spine, the floor of the nose, the mesial and the distal parts of the maxillary sinus, the palatal process of the maxilla and the pterygoid plate(where the sphenoid bone is connected to the maxilla).**

**(Ihde&Ihde, Immediate Loading).

         The basal implantology makes no use of the spongy(trabecular) bone, but if it still exists, the trabecular bone can be compressed laterally, and in that way, additional stability for the compression screw implants can be achieved. This process is called “lateral corticalisation”.

 

         The cortical anchorage and the lateral corticalisation, combined with simultaneous implant splinting, provide stable foundation for the immediate loading of the intraosseous dental implants.

 

 

 
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