Effects of removable dental prostheses on masticatory performance of subjects with shortened dental arches: A systematic review

OBJECTIVE: To synthesise data on the effects of distal-extension removable dental prostheses (RDPs) on masticatory performance of subjects with (extreme) shortened dental arches ((E)SDAs). DATA: Search terms were: 'masticatory' respectively 'chewing' combined with 'performance', 'efficiency', or 'ability'. SOURCES: An electronic search restricted to the years 2003-2014 in PubMed, Medline, Cochrane Library, Embase, and Science Direct databases. STUDY SELECTION: Studies exposing data on subjects with SDA (3-5 posterior occluding pairs) or ESDA (0-2 posterior occluding pairs) and on masticatory performance with RDP were included. RESULTS: Four studies provided data on comminution, three on mixing ability, and one on both tests. Comminution or mixing ability in subjects with (E)SDA was 28-39% lower compared to that of subjects with complete dentitions. In two studies, comminution outcomes when chewing with an RDP ranged from 2% to 32% reduction, indicating better chewing function (smaller X50) compared to comminution without the RDP. One study reported 28-83% lower mixing ability when chewing at the RDP side than chewing at the dentulous side. Generally, more artificial teeth (or longer occlusal platform) in experimental RDPs resulted in better comminution and better mixing ability (significant in four out of five studies), indicating a 'dose-effect' relationship. CONCLUSIONS: (1) Subjects with (E)SDA had a 30-40% reduced masticatory performance; (2) distal-extension RDPs could compensate this reduction partially (some 50%); and (3) more artificial teeth in RDPs resulted in better performance. CLINICAL SIGNIFICANCE: Distal-extension RDPs in subjects with SDA partially compensate reduced masticatory performance