الفهرس 
Wear resistance and long-term retention of novaloc versus traditional ball and socket implant attachments retaining mandibular complete overdenture in vitro study
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Abstract
Implant retained overdentures have been used widely to solve the problem of complete
edentulism. They provide better retention and more patient satisfaction than the conventional
complete dentures. However, the attachments used in these overdentures usually suffer from wear
and may cause retention problems by time. The retention of these overdentures depends mainly on
the type and design of the used attachments.
The aim of this in-vitro study was to compare between the wear behavior and retention of two
different attachments: Ball and Novaloc. The male part of Ball attachment was made of titanium and
had a titanium elliptical female housing with a golden retention insert. As for the other attachment,
the male part of Novaloc was made of carbon-based coating abutment and had a female housing made
of PEEK with a white retention Peek insert.
One epoxy resin model was fabricated for each group. Two implant analogues were inserted
in each model at the canine area bilaterally. Four overdentures were made and divided randomly into
two equal groups corresponding to Ball group and Novaloc group. Picking up of the overdentures
was done with the right female part of each attachment, then a hook representing the geographical
center of each denture was attached to it.
ROBOTA chewing simulator was used for the insertion and removal cycles of these dentures.
The software analyzed the wear of each cap regarding area, diameter, and perimeter. Then their
surface was evaluated microscopically by digital microscope. This analysis was done at different
intervals: baseline, 500 cycles, 1000 cycles, 1500 cycles and 2000 cycles to simulate a follow up of
1 year. Retention was also measured by universal testing machine at the same intervals mentioned
before.
The results showed that both groups suffered from wear by time and there was a statistically
significant decrease in retention. The initial and final retention of Ball was higher than that of
Novaloc. This may be attributed to the material of each of them, as the metal-to-metal friction between
the male titanium part and the golden insert of the ball attachment showed better retention results than
the metal-to-polymer friction between the male part of Novaloc and its PEEK cap and insert.