Posts Tagged ‘ bone

Destruction of Osseointegration

Bone resorption will occur at sites of inflammation or prolonged excessive stimulation. The main contributing factors to bone resorption are local inflammation from plaque accumulation and trauma from occlusion. Periodontal disease from plaque inflammatory response, and subsequent bone resorption can result from the following:

  • Direct action of plaque products on bone progenitor cells induce their differentiation into osteoclasts.
  • Plaque products directly on bone, destroying it through a non cellular mechanism.
  • Plaque products stimulate gingival cells, causing them to release mediators which in turn induce bone progenitor cells to differentiate in osteoclasts.
  • Plaque products cause gingival cells to release agents that can act as cofactors in bone resorption.
  • Plaque products cause gingival cells to release agents that destroy bone by direct chemical action without osteoclasts.
Resorbable Tissue Replacement (RTR) mixed with patient's blood

Resorbable Tissue Replacement (RTR) mixed with patient’s blood

Osteotomy

All surgical techniques to elevate the maxillary sinus present the possibility of perforating the Schneiderian membrane. The complication can occur during osteotomy which performed with burs. It can also occur during the elevation of Schneiderian membrane using manual elevators.

Piezoelectric bone window osteotomy cuts bone without damaging the soft tissue. Piezoelectric membrane elevation separates the Schneiderian membrane without perforations.

The elevation of Schneiderian membrane from the sinus floor is performed using both piezoelectric elevators and the force of a physiologic solution subjected to piezoelectric cavitation.

Divisions of Available Bone for Dental Implants

There are four divisions of available bone based on width, height, length, angulation and crown height in the edentulous site.

1. Division A edentulous ridge offer abundant bone in all dimensions.
2. Division B bone may provide adequate width for narrower, small diameter root form endosteal implants.
3. Division C edentulous ridge exhibits moderate resorption and presents more limiting factors for predictable endosteal implants.
4. Division D edentulous ridge basal bone loss and severe atrophy, resulting in dehiscent mandibular canals or a completely flat maxilla.

Reference
Misch CE: Dental Implant Prosthetics, Mosby Inc 2005

Irradiation of Bone with Dental Implants

Radiation therapy is defined as the therapeutic use of ionizing radiation. The 2 principal types of ionizing radiation are electromagnetic irradiation and particle irradiation. In irradiation of implants in bone, it is recommended the removal of all abutments and superstructures and closure of skin and mucosa over the implants prior to radiation. [1] Radiation therapy can begin when healing is complete.

Irradiation of dental implants in bone results in backscatter. The tissues on the radiation source side of the implants receive a higher dose than the other tissues in the field. The dose in increased by about 15% at 1 mm from the dental implant. [2]

References
1. Granstrom G, Tjellstrom A, ALbrektsson T: Postimplantation irradiation for head and neck cancer treatment. Int J Oral Maxillofacial Implants 1993;8(4):495-500.
2. Wall JA, Burkee EA: Gamma dose distribution at and near the the interface of different materials. IEEE Trans Nucl Sci 1970; 17:305.

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