title: Stress analysis in oral obturator prostheses, part II: photoelastic imaging.
abstract: In part I of the study, two attachment systems [O-ring; bar-clip (BC)] were used, and the system with three individualized O-rings provided the lowest stress on the implants and the support tissues. Therefore, the aim of this study was to assess the stress distribution, through the photoelastic method, on implant-retained palatal obturator prostheses associated with different attachment systems: BOC--splinted implants with a bar connected to two centrally placed O-rings, and BOD--splinted implants with a BC connected to two distally placed O-rings (cantilever). One photoelastic model of the maxilla with oral-sinus-nasal communication with three parallel implants was fabricated. Afterward, two implant-retained palatal obturator prostheses with the two attachment systems described above were constructed. Each assembly was positioned in a circular polariscope and a 100-N axial load was applied in three different regions with implants by using a universal testing machine. The results were obtained through photograph record analysis of stress. The BOD system exhibited the highest stress concentration, followed by the BOC system. The O-ring, centrally placed on the bar, allows higher mobility of the prostheses and homogeneously distributes the stress to the region of the alveolar ridge and implants. It can be concluded that the use of implants with O-rings, isolated or connected with a bar, to rehabilitate maxillectomized patients allows higher prosthesis mobility and homogeneously distributes the stress to the alveolar ridge region, which may result in greater chewing stress distribution to implants and bone tissue. The clinical implication of the augmented bone support loss after maxillectomy is the increase of stress in the attachment systems and, consequently, a higher tendency for displacement of the prosthesis.
authors: University Estadual Paulista, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba 16015-050, SP, Brazil.
authors: Aldiéris Alves
authors: AA
authors: Pesqueira
authors: University Estadual Paulista, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba 16015-050, SP, Brazil.
authors: Marcelo Coelho
authors: MC
authors: Goiato
authors: University Estadual Paulista, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba 16015-050, SP, Brazil.
authors: Emily Vivianne Freitas
authors: EV
authors: da Silva
authors: Federal University of Alfenas-Unifal, Dental School, Department of Restorative Dentistry, Alfenas 37130-000, MG, Brazil.
authors: Marcela Filié
authors: MF
authors: Haddad
authors: University Estadual Paulista, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba 16015-050, SP, Brazil.
authors: Amália
authors: A
authors: Moreno
authors: University Sagrado Coração, Faculty of Dentistry, Department of Oral Biology, Bauru 17011-160, SP, Brazil.
authors: Abbas
authors: A
authors: Zahoui
authors: University Estadual Paulista, Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba 16015-050, SP, Brazil.
authors: Daniela Micheline
authors: DM
authors: dos Santos
mesh_terms: D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000379:methods*; D004548:Elasticity; D006801:Humans; D008409:Mastication; D008437:Maxilla / Q000473:pathology* / Q000601:surgery; D003765:Models, Dental; D008962:Models, Theoretical; D010158:Palatal Obturators; D011474:Prosthesis Design; D013314:Stress, Mechanical