Longitudinal study on forces transmitted from denture base to retainers of lower free-end saddle dentures with Aker's...

The aim of this study was to make a longitudinal analysis of the forces transmitted from denture base to retainers of lower free-end saddle dentures with Aker's clasps using a newly developed transducer. The experimental apparatus consisted of two components, a metal framework and a denture base embedded with a force-detecting unit. This device was the transducer, which could detect changes in lateral and vertical forces transmitted from denture base to retainers at the same time. Forces were measured on several separate occasions from the insertion of new dentures to about 4 months afterwards. The result are summarized as follows: (i) the maximal mean value of vertical forces transmitted from denture base to retainers was decreased after 1 week of insertion of new dentures, then increased and reached a constant level (about 10N) 4-6 weeks after the insertion of new dentures; (ii) there were large differences in the maximal mean value of lateral forces between subjects.