SummaryThe purpose of this study was to perform longitudinal measurement of forces transmitted from the denture base to retainers of lower distal‐extension removable partial dentures with a conus crown telescopic system. The experimental denture was embedded with a force‐detecting unit which could detect a change in lateral and vertical forces transmitted from denture base to retainers at the same time. Forces were measured during chewing of food on several separate occasions from the insertion of new dentures to about 3 months after. Max.ver (maximal mean value of vertical force) and Max.lat (maximal mean value of lateral force) were calculated from the peak level of all strokes of chewing of food at the minimum of the interocclusal distance.The results are summarized as follows:(i)There were no significant changes of Max.ver and Max.lat;(ii)There were no significant differences of Max.ver between subjects the value of which was about 20 N;(iii)There were significant differences of Max.lat between subjects the value of which was less than 1