title: Retentive Properties of O-Ring and Locator Attachments for Implant-Retained Maxillary Overdentures: An In Vitro Study.
abstract: OBJECTIVE
  To evaluate and compare retentive properties of O-ring and Locator attachments for implant-retained maxillary overdentures.
  
  
  METHODS
  Four implant analogs were inserted in canine and second premolar areas of an acrylic edentulous maxillary model. A metal-reinforced experimental acrylic overdenture was constructed and connected to the analogs using either O-ring (group I) or Locator (group II) attachments. Locators were divided into 3 subgroups according the degree of retention of the patrix nylon insert: Locator extra-light retention (group IIa), Locator light retention (group IIb), and Locator medium retention (group IIc). Vertical and oblique (lateral, anterior, and posterior) dislodging forces were measured at the beginning of the study (initial retention) and after 540 cycles of denture insertion and removal (final retention).
  
  
  RESULTS
  For vertical, lateral, and anterior dislodging, group IIc recorded the highest initial and final retention, and group I recorded the lowest retention. For posterior dislodging, group I recorded the highest retention, and group IIa recorded the lowest retention. For group II, vertical dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For group I, posterior dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For all dislodging forces (except posterior dislodging), the highest retention loss was recorded in group I, and the lowest retention loss was recorded in group IIa.
  
  
  CONCLUSIONS
  Locator medium attachment was associated with favorable retention during axial (vertical) and nonaxial (anterior and lateral) dislodging compared to other types of Locator inserts and O-ring attachments after a simulated 6-month period of overdenture use.
authors: Department of Removable Prosthodontics, Faculty of Dentistry, University of Mansoura, Eldakahlia, Egypt.
authors: Moustafa Abdou
authors: MA
authors: ELsyad
authors: Department of Removable Prosthodontics, Faculty of Dentistry, University of Mansoura, Eldakahlia, Egypt.
authors: Abdelsalam Amohamed
authors: AA
authors: Elhaddad
authors: Department of Removable Prosthodontics, Faculty of Dentistry, University of Mansoura, Eldakahlia, Egypt.
authors: Ahmed Samir
authors: AS
authors: Khirallah
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design / Q000295:instrumentation / Q000379:methods; D019094:Dental Prosthesis, Implant-Supported / Q000295:instrumentation / Q000379:methods*; D003799:Dental Stress Analysis; D003781:Denture Retention / Q000295:instrumentation / Q000379:methods*; D003828:Denture, Overlay; D006801:Humans; D066298:In Vitro Techniques; D008437:Maxilla; D003765:Models, Dental
keywords: Locator; O-ring; Retention; implant; overdentures