title: Influence of length of occlusal support on masticatory function of free-end removable partial dentures.
abstract: OBJECTIVE
  The aim of this study was to determine the influence of occlusal support length (OSL) of free-end removable partial dentures (RPDs) on masticatory function.
  
  
  METHODS
  Twenty-three subjects (mean age: 55.2 ± 8.4 years) who were edentulous in the maxilla and classified as Kennedy Class I in the mandible were selected. Subjects received new maxillary complete dentures and mandibular RPDs. Five OSL conditions were determined by RPD artificial tooth wear: full occlusal support (L1, control), OSL to first molar (L2), OSL to second premolar (L3), OSL to first premolar (L4), and absence of occlusal support (L5). Masticatory performance and efficiency were evaluated using the sieve method. Chewing rate was defined as the number of masticatory cycles per minute. Bolus selection opportunities and bolus breakage function were evaluated using the one-chew method. Qualitative and quantitative measurements of masticatory cycle patterns were recorded kinesiographically. Data were analyzed using repeated-measures analysis of variance and Friedman and Fisher exact tests (α = .05).
  
  
  RESULTS
  Masticatory performance and efficiency decreased (P < .05) from L1 (5.46 ± 0.64 mm and 51.21% ± 19.44%, respectively) to L5 (6.24 ± 0.44 mm and 24.50% ± 15.98%, respectively). Chewing rate was higher for L4 than L1 (P < .05). Bolus selection chances and bolus breakage function decreased as OSL was reduced (P < .05); however, there were no differences in masticatory cycle pattern among the OSL conditions (P > .05).
  
  
  CONCLUSIONS
  Reduction of OSL altered masticatory function, thereby decreasing masticatory performance and efficiency resulting from a lower capacity to select and break down food.
authors.affiliation: Department of Prosthodontics and Periodontology, State University of Campinas, Sao Paulo, Brazil.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Sanchez-Ayala
authors.forename: Glaucia Maria Bovi
authors.initials: GM
authors.lastname: Ambrosano
authors.forename: Renata Cunha Matheus
authors.initials: RC
authors.lastname: Rodrigues Garcia
mesh_terms: D003766:Dental Occlusion; D019554:Dental Restoration Wear; D003799:Dental Stress Analysis; D003779:Denture Design; D003827:Denture, Complete, Upper; D003832:Denture, Partial, Removable; D005260:Female; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000503:physiopathology*; D008297:Male; D008334:Mandible; D008409:Mastication; D008875:Middle Aged