Ahmadzadeh and Teimouri
BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS COMPARISON OF STRESS DISTRIBUTION AROUND IMPLANTS 461
previous study, locator, ball and bar-clip attachments,
respectively, caused the highest amount of stress to the
bone around the implant in maxilla. Valentim et al.
obtained similar results by investigating Ball & Bar,
Ball and Bar attachments in the mandible by apply-
ing a vertical force of 100 N and found that the high-
est stress was fed through the Ball type attachment to
the bone around the implant. In the present study, the
highest level of stress in the bone around the implant
was concentrated in the implant neck region, which
was completely consistent with the results of the pre-
vious studies. In the study of stress in metal parts in
ball attachments, the stress concentration occurred in
the cervical area of the attachment in the 5th tooth
of the right implant area. The stress concentration for
the bar-clip attachment was observed between the 5th
and 3rd tooth right implants. In the locator attachment,
the greatest stress in the housing area of the locator
attachment was entered into the right side of the 5th
tooth. Compared to the different treatment designs, the
stress at the bar-clip attachments was higher than the
other two. It is recommended to use the bar-clip treat-
ment design in some cases where reducing stress in the
bone around the implant is more important than over-
denture stability and stress in the metal parts. If there
is no necessity in these cases, you can use the Ball and
Locator treatment designs as needed.
The greatest amount of bone stress in all treatment
designs was concentrated in the cervical implants in the
working side and a few upper threaded implants, and
the stress rate didn’t reach to the ultimate bone strength
in any of the treatment designs, thus, it seems that bone
resorption will not occur in any none of the treatment
designs. In clinical situations where overdenture is
expected to undergo lot of force, it is recommended to
use the Bar-Clip treatment design because less stress is
transmitted to the bone around the implant. The maxi-
mum stress induced in the implant-based overdenture
model was observed in the locator attachment, and the
implant overdenture supported by the Bar-clip attach-
ment with less stress was the most appropriate design
for the present study.
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