title: A comparison of the effect of different occlusal forms in mandibular implant overdentures.
abstract: BACKGROUND
  Posterior tooth form selection for implant overdentures is made according to personal preference and experience using the concepts of conventional complete denture prosthodontics.
  
  
  OBJECTIVE
  This study (1) compared the masticatory efficiency of three occlusal forms, 0 degrees, 30 degrees, and lingual contact (lingualized occlusion), in subjects with mandibular implant overdentures, and (2) determined their effects on the implant supporting tissues.
  
  
  METHODS
  Eight patients who had four root form implants in the mandibular symphysis area connected with a Hader bar were selected. Maxillary and mandibular dentures were constructed for each patient with interchangeable posterior segments and the three occlusal forms were tested. The masticatory efficiency for each posterior tooth form was assessed with objective food tests and a subjective patient preference questionnaire. Periodic evaluation of implant-supporting tissues also was performed.
  
  
  RESULTS
  Reliability analysis showed that all R1 coefficients were > or =0.80 (<0.001), indicating high subject consistency between multiple chewing efficiency trials. MANOVA analysis indicated a significant difference in chewing efficiency among the three occlusal forms (p < 0.001). The 0 degree occlusal form was associated with a significantly higher number of chewing strokes compared with 30 degrees or lingualized occlusal forms. The different occlusal forms were not found to have a clinically detrimental effect on the peri-implant soft or hard tissues.
  
  
  CONCLUSIONS
  Chewing efficiency tests and patient preference ratings showed that 30 degree teeth and lingual contact provided better chewing efficiency than 0 degree teeth. None of the tested occlusal forms showed any clinical or radiographic detrimental effect on the implant-supporting tissues.
authors.affiliation: Department of Maxillofacial Prosthodontics, University of Pittsburgh Medical Center, PA 15213, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Khamis
authors.forename: H S
authors.initials: HS
authors.lastname: Zaki
authors.forename: T E
authors.initials: TE
authors.lastname: Rudy
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003828:Denture, Overlay; D005260:Female; D005502:Food; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology; D008409:Mastication / Q000502:physiology; D008875:Middle Aged; D015999:Multivariate Analysis; D017060:Patient Satisfaction; D010519:Periodontium / Q000502:physiology; D011859:Radiography; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014093:Tooth, Artificial