A within‐subject clinical trial on the conversion of mandibular two‐implant to three‐implant overdenture: Patient‐centered outcomes and willingness to pay

Objectives To examine the impact of adding a third midline implant with stud attachment to a mandibular two‐implant overdenture on patient‐oriented outcomes. Methods In this pre–post design clinical trial, following the standard procedures, mandibular two‐implant overdentures of 17 edentulous individuals (61.9 ± 6.6 years) were converted to three‐implant overdentures by adding a stud attachment to an unloaded midline implant. Patient‐oriented outcomes included patient expectations and satisfaction with implant overdenture as well as willingness to pay the cost of conversion. Data were collected at baseline and at the 6‐week follow‐up using visual analog and binary scales as well as open‐ended questions. Statistical analysis included descriptive statistics, Spearman's correlation, Fisher exact test, Mann–Whitney U test, and the exact sign test. Results After connecting the third midline implant to the mandibular two‐implant overdenture, there was a statistically significant decrease in the anteroposterior movement (p = 0.005) as evaluated by clinicians. Moreover, study participants reported an increase in perceived stability of the overdenture (95% CI; 0.68–1.00, p = 0.002) and in their ability to speak (95% CI; 0.63–1.00, p = 0.008). The addition of a third implant met the expectations of 94% of patients in regard to lower denture stability, 100% for retention, and 82.4% for comfort. The mandibular three‐implant overdenture increased patient general satisfaction over a short period of time, but this improvement was not statistically significant. About 80% of patients would recommend this type of prosthesis to their peers but only 47% of them would agree to pay a large increase in the cost of treatment compared to a two‐implant overdenture. Conclusions The addition of a midline third implant to an existing mandibular two‐implant overdenture resulted in several improved patient‐reported outcomes.