A Cost-effectiveness Analysis of the Single-implant Mandibular Overdenture Treatment

Single-implant Mandibular Overdenture or a Conventional Complete Denture? A Cost-effectiveness Analysis Alongside a Randomized Clinical Trial

The aim of this study is to assess the cost-effectiveness of the mandibular overdenture retained by a single implant. The study hypothesis is that SIMO is more effective but more costly than the conventional denture, though this incremental cost is relatively low for the offered effectiveness in terms of clinical and patient-reported outcomes.

This randomized clinical trial alongside a cost-effectiveness analysis will include twenty-eight edentulous individuals who meet eligibility criteria. New maxillary and mandibular dentures will be fabricated for all participants following a standardized protocol. Then, participants will be randomized into one of the treatment groups: conventional complete denture group or single-implant mandibular overdenture group. Each participant allocated to the overdenture group will then receive a Straumann® Standard Plus SLActive® regular neck implant (Straumann 0.33.051S/052S/053S Institute Straumann AG, Basel, Switzerland) in the mandibular midline. A healing abutment will be connected and the implant will be allowed to heal for approximately 3 weeks. Then, a 3.4mm retentive titanium anchor abutment (Straumann 048.439, Institute Straumann AG, Basel, Switzerland) will be connected and tightened to 35 N.cm with a torque wrench. The matrix will be incorporated to the denture using self-curing acrylic resin and the patient will be instructed to keep the upper and lower dentures firmly occluded in the habitual position until the final polymerization of the resin. Direct costs related to therapies in both groups will be identified, measured and valuated for one year after treatment and patient-reported outcomes will be assessed. Incremental cost-effectiveness ratios will be estimated and graphically presented on cost-effectiveness planes. A Markov decision tree will be constructed to set out the consequences of the competing alternatives. Sensitivity analysis on the most important assumptions will be performed in order to assess the robustness of the model.

Inclusion Criteria:

• No contraindications for implant surgery (mainly related to uncontrolled systemic diseases)
• Present enough bone volume in the mandibular midline area for implant placement without the need of bone augmentation procedures.
• Be able to understand and answer the questionnaires used in the study
• Agree to participate by providing a written informed consent.

Exclusion Criteria:

• Noncompliant participants
• Individuals who do not agree to be randomly allocated to the treatment study group
• Presence of signs of untreated temporomandibular disorders, uncontrolled systemic or oral conditions that require additional treatments