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

Abstract

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: ClinicalTrials.gov, 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.

Conflict of interest statement

Ethics approval and consent to participate

All participants will provide informed written consent prior to registration in this trial and will be informed of their right to withdraw at any time. Consent, study forms and the entire trial will follow the principles set by the Tri-Council Policy Statement [24]. This protocol was approved by the McGill University (A03-M07-17A) and MUHC REB (2018–3873). Additional file 3 presents ethical approval documents. A version of this protocol was registered in the https://ichgcp.net/clinical-trials-registry/NCT03126942.

We will formally communicate any amendments to the protocol during the trial to the IRB. If approved, amendments will be recorded on Clinicaltrials.gov and divulged to participants; the latter will be given time to reflect on their continued participation.

Participants will be formally enrolled in the trial only after the signed informed consent form is obtained (Additional file 4). A researcher will explain the aims and nature of the study to each participant before signing the consent form. It will be elucidated that participation is voluntary and that participant are free to withdraw from the study at any time without providing a reason. Compensation to participants will involve the cost of transportation for the data collection appointments, including the baseline assessment. Participants will receive treatment with single implant overdentures at no cost, as well as maintenance of this treatment during the follow-up period.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1

Flowchart of the RCT (adapted from the CONSORT statement). For each follow-up, numbers of withdrawn and lost participants will be reported with reasons

Fig. 2

Study schedule: enrolment, allocation, interventions, baseline, and post-intervention assessments