Single-implant overdentures retained by the Novaloc attachment system: study protocol for a mixed-methods randomized cross-over trial

Trials. 2018 Apr 23;19(1):243. doi: 10.1186/s13063-018-2606-7.


Background: Overdentures retained by a single implant in the midline have arisen as a minimal implant treatment for edentulous mandibles. The success of this treatment depends on the performance of a single stud attachment that is susceptible to wear-related retention loss. Recently developed biomaterials used in attachments may result in better performance of the overdentures, offering minimal retention loss and greater patient satisfaction. These biomaterials include resistant polymeric matrixes and amorphous diamond-like carbon applied on metallic components. The objective of this explanatory mixed-methods study is to compare Novaloc, a novel attachment system with such characteristics, to a traditional alternative for single implants in the mandible of edentate elderly patients.

Methods/design: We will carry out a randomized cross-over clinical trial comparing Novaloc attachments to Locators for single-implant mandibular overdentures in edentate elderly individuals. Participants will be followed for three months with each attachment type; patient-based, clinical, and economic outcomes will be gathered. A sample of 26 participants is estimated to be required to detect clinically relevant differences in terms of the primary outcome (patient ratings of general satisfaction). Participants will choose which attachment they wish to keep, then be interviewed about their experiences and preferences with a single implant prosthesis and with the two attachments. Data from the quantitative and qualitative assessments will be integrated through a mixed-methods explanatory strategy. A last quantitative assessment will take place after 12 months with the preferred attachment; this latter assessment will enable measurement of the attachments' long-term wear and maintenance requirements.

Discussion: Our results will lead to evidence-based recommendations regarding these systems, guiding providers and patients when making decisions on which attachment systems and implant numbers will be most appropriate for individual cases. The recommendation of a specific attachment for elderly edentulous patients may combine positive outcomes from patient perspectives with low cost, good maintenance, and minimal invasiveness.

Trial registration:, NCT03126942 . Registered on 13 April 2017.

Keywords: Complete denture; Costs and cost analysis; Cross-over studies; Dental care for aged; Edentulous mouth; Implant-supported dental prosthesis; Minimally invasive surgical procedures; Patient outcome assessment; Patient satisfaction; Removable prosthodontics.

Publication types

  • Clinical Trial Protocol

MeSH terms

  • Age Factors
  • Aged
  • Cross-Over Studies
  • Dental Care for Aged / instrumentation*
  • Dental Care for Aged / methods
  • Dental Prosthesis, Implant-Supported*
  • Denture, Overlay*
  • Female
  • Humans
  • Jaw, Edentulous / diagnostic imaging
  • Jaw, Edentulous / surgery*
  • Male
  • Mandible / diagnostic imaging
  • Mandible / surgery*
  • Patient Satisfaction
  • Prosthesis Design
  • Quebec
  • Randomized Controlled Trials as Topic
  • Time Factors
  • Treatment Outcome

Associated data