title: A comparison of mandibular denture base deformation with different impression techniques for implant overdentures.
abstract: OBJECTIVE
  This study aimed to evaluate mandibular denture base deformation along with three impression techniques used for implant-retained overdenture.
  
  
  METHODS
  Ten edentulous patients (five men and five women) received two implants in the canine region of the mandible and three duplicate mandibular overdentures which were constructed with mucostatic, selective pressure, and definitive pressure impression techniques. Ball abutments and respective gold matrices were used to connect the overdentures to the implants. Six linear strain gauges were bonded to the lingual polished surface of each duplicate overdenture at midline and implant areas to measure strain during maximal clenching and gum chewing.
  
  
  RESULTS
  The strains recorded at midline were compressive while strains at implant areas were tensile. Clenching recorded significant higher strain when compared with gum chewing for all techniques. The mucostatic technique recorded the highest strain and the definite pressure technique recorded the lowest. There was no significant difference between the strain recorded with mucostatic technique and that registered with selective pressure technique. The highest strain was recorded at the level of ball abutment's top with the mucostatic technique during clenching.
  
  
  CONCLUSIONS
  Definite pressure impression technique for implant-retained mandibular overdenture is associated with minimal denture deformation during function when compared with mucostatic and selective pressure techniques. Reinforcement of the denture base over the implants may be recommended to increase resistance of fracture when mucostatic or selective pressure impression technique is used.
authors.affiliation: Removable Prosthodontics, Faculty of Dentistry, Mansoura University, Eldakahlia, Egypt. m_syad@mans.edu.eg
authors.forename: Moustafa Abdou
authors.initials: MA
authors.lastname: Elsyad
authors.forename: Fatma Ahmad
authors.initials: FA
authors.lastname: El-Waseef
authors.forename: Yasmeen Fathy
authors.initials: YF
authors.lastname: Al-Mahdy
authors.forename: Mohammed Mohammed
authors.initials: MM
authors.lastname: Fouad
mesh_terms: D003761:Dental Impression Technique; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D003819:Denture Bases; D003779:Denture Design; D003828:Denture, Overlay; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation*; D008297:Male; D008334:Mandible; D008875:Middle Aged