Title: A pilot randomised controlled trial to compare the costs and effects of Conventional Implants with Mini Implants used to retain full lower DENTures (CIMI-DENT trial)
Funder: Department of Health (England)

Abstract: Background About 6% of the population have no natural teeth[2]. Whilst most patients can successfully adapt to an upper denture, full lower dentures are much more problematic due to the lack of retention provided by the mandible, this deteriorates as the bone under the denture is resorbed. Titanium implants have a strong evidence base to demonstrate their longevity and effectiveness in retaining lower dentures [3-14]. Mini implants have been recently introduced [15-20] but there is no high quality information to compare the performance of the two systems A large, high quality RCT is required to inform clinical practice and NHS policy, however the information required to conduct a large trial with minimum risk is missing. Aims The aim of the pilot trial is to provide the necessary information to design and conduct a large, high-quality randomized controlled trial to compare the costs and effects of mini-implants with conventional implants in patients who cannot wear a conventional lower denture. There are a number of areas of uncertainty in the design and conduct of an evaluation of these interventions within this population, which currently preclude evaluation using a full trial. More specifically we will collect information on the following areas: Appropriateness of outcome measures and the acceptability of methods used to collect them Recruitment and retention rates Experiential learning on the operational management of a trial on dental implants Plan of investigation Edentulous patients who have problems warning full lower dentures wearing referred to specialist care at the University of Manchester Dental Hospital will be the target population. A total of 44 eligible patients consenting to participate in the study will be randomised to receive either conventional or mini-implants. Following randomisation all patients will receive baseline assessment using quality of life measures and ‘gummy jelly’ to objectively assess function. Pain scores will be recorded at 24 hours and 1 week post-operatively. Patients will be followed and outcomes assessments made at 2 months (when the implants first retain the lower denture) and 6 months after surgery. Direct (staff, equipment, consumables) and indirect costs will be measured. Information on recruitment and retention of patients, suitability and variability of proposed outcome measures and methods of gathering economic data will be collected. Information on adverse events will also be collected. Analyses will be descriptive using ranges, frequency distributions and measures of central tendency and variability. I addition to the trial, data on the total number of referrals, the number and proportion who attend and the number and proportion who require implants after technically sound dentures have been fitted will be collected from clinical and administrative records over a prescribed 12 month period. Potential benefits to patients / NHS Mini-implants have been recently introduced into clinical practice and are funded by the NHS but both clinical and commissioning decision-making is not informed by high-quality evidence. Mini-implants are at face value attractive to patients, clinicians and commissioners because of their ease of placement, minimal surgery, and reduced costs, but we don’t know how well they perform in comparison to conventional implants in terms of patient-rated outcomes and long term follow up. We could find that mini-implants do not perform as well as conventional implants and patients need to have them replaced with conventional implants, resulting in patients needing two procedures and the NHS paying twice. A full-scale trial is needed to inform NHS policy on implant-retained lower full dentures to ensure the NHS provides the best care for patients and offers value for money for the tax-payer. This pilot trial provides the information needed to design such a trial with minimum risk.


Research activity codes: 6.3 MEDICAL DEVICES
Health categories: ORAL AND GASTROINTESTINAL