Journal of Dental Research, Vol 55, 59-65, Copyright © 1976 by International & American Associations for Dental Research Online Journals
Stress concentrations at the apex of pinned, implanted teeth
S. C. Gambrell Jr and J. M. Allen Jr
Stress in the alveolus at the apex is reduced when the implant is held by a
pin through the alveolar wall. This stress reduction is effected by
transfer of part of the coronal force to the alveolar wall by the pin. Pin
positions centrally located between the apex and the alveolar crest provide
the greatest reduction of stress concentration in the alveolus at the apex.
Since the bone is especially fragile near the alveolar crest, care must be
taken when the pin is positioned in this region. Positioning the pin near
the apex has the least effect on reducing the stress in the alveolus at the
apex. Although no data were obtained relating to stress in the alveolar
wall at points of pin penetration, results given here do indicate that from
7 to 30% of the intrusion component of the coronal force is transmitted to
the alveolar wall by the pin. Additional research is needed to determine
the effects of stress at the pin through the alveolar wall because of load
transfer by the pin from the implant to the alveolar wall. The situation in
the alveolar wall would be one of creation of a completely unnatural stress
rather than reduction of an existing stress, as was the case at the apex.
Whether the reduction of stress at the apex and the creation of stress at
the pin through the alveolar wall are of physiological benefit is a
question that must yet be answered.
