Statement of Problem: Maxillary sinus and its expansion poises primary causes to a decreased bone height at the
molar area, prohibiting placement of dental implants of reasonable sizes to a favorable direction.
Purpose: Investigation of the stresses around dental implants placed closed to the maxillary sinus which are subject to
various loading conditions.
Material and methods: ITI solid implants of 6mm in length and 4.8mm in diameter placed at the molar region of
maxilla were axisymmetrically modeled for a series of finite element analyses. Main consideration was given to the
stresses at the cervical cortical bone induced by loads of 50N inclined to the implant axis as a result of inclined
plantation of the
implants. Based on the inclination angle between the load and the implant axis, seven different models were set for
analyses. Resultant displacement and compressive stresses at the cervical bone were evaluated.
Results and Conclusions:
1. Higher stresses were observed at the cervical area of all the models.
2. The peak stresses at the cervical bone varied as a function of the inclination angle of the load. The bigger the angle,
the higher the stress tended to occur.
3. Resultant displacement increased more rapidly in accordance with the inclination of the implant or the loading.
4. Stress of 3-4MPa was cautiously envisaged and assumed as the allowable level to the cyclic bone stress. Under this
assumption, the inclination angle need to be controled to be within 5-13 degree for the present model. In the light of
possible stress reduction followed by an adaption process at the cervical bone, however, a slightly bigger inclination
might be accepted.