title: Mandibular Overdentures Retained by Two Mini-Implants: A Seven-Year Retention and Satisfaction Study.
abstract: OBJECTIVE
  Patients with atrophic edentulous ridges generally have problems with retention, therapeutic satisfaction, and comfort with their complete dentures. An alternative treatment to assist in improving retention and stability involves the use of mini-implants. The aim of this study was to evaluate the retention of mandibular overdentures connected to two mini-implants and overall patient satisfaction with them.
  
  
  METHODS
  Seven patients with atrophic mandibular ridges (Type 4D Misch classification), aged 62 to 74 years old were rehabilitated with complete dentures. In each patient, two mini-implants measuring 15 or 13 mm in length and 1.8 mm in diameter were placed. After 15 days, overdentures were connected to the mini-implants with O-ring attachments. In each patient, retention of the overdentures was measured, and a survey of therapeutic satisfaction before and after connection to the mini-implants was administered. Prosthesis retention was measured with a digital dynamometer at 1 month, 6 months, and 2, 3, 5, and 7 years after mini-implant placement. Patient satisfaction was assessed with a survey. Data were analyzed with Student's t-test (satisfaction survey) and the Friedman test (retention measurements and satisfaction survey).
  
  
  RESULTS
  The initial retention values (0.34 to 0.63 N without mini-implants) varied significantly (p ≤ 0.050). These values were less than the subsequent measurements of 3.92 to 9.64 N, taken after placement of the mini-implants and connecting them to the dentures. Satisfaction was good to very good over the 7-year observation period. Mucosa and peri-implant bone showed no pathological changes.
  
  
  CONCLUSIONS
  In this limited sample size clinical study the results indicated that after connecting mandibular overdentures to two mini-implants, patient satisfaction significantly increased and retention significantly improved during the 7-year observation period.
authors.affiliation: Department of Oral Rehabilitation, Faculty of Dentistry, University of Concepcion, Concepcion, Chile.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Catalán
authors.affiliation: Department of Oral Rehabilitation, Faculty of Dentistry, University of Concepcion, Concepcion, Chile.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Martínez
authors.affiliation: Department of Oral Pathology, Faculty of Dentistry, University of Concepcion, Concepcion, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Marchesani
authors.affiliation: Department of Oral Rehabilitation, Faculty of Dentistry, University of Concepcion, Concepcion, Chile.
authors.forename: Urcesino
authors.initials: U
authors.lastname: González
mesh_terms: D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003781:Denture Retention; D003826:Denture, Complete, Lower; D003828:Denture, Overlay; D005500:Follow-Up Studies; D006801:Humans; D008334:Mandible; D017060:Patient Satisfaction; D010549:Personal Satisfaction; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants
keywords: Mini-implants; overdenture; retention; satisfaction