Zirconia vs titanium for overdentures: a 14-point success gap and more bone loss at 3 years

Zirconia implants are marketed on aesthetics and a metal-free promise, but how do they actually perform against titanium over the medium term? This 3-year split-mouth randomized controlled trial put the two materials in the same mouths. Twenty fully edentulous patients each received two zirconia and two titanium two-piece implants in the anterior mandible to support removable overdentures, with computer-generated randomization deciding placement. The primary endpoint was bleeding on probing at 12 months; secondary outcomes included survival, success by Albrektsson criteria, marginal bone level change, peri-implant cytokines (IL-1β, IL-6, TNFα), prosthetic complications and patient-reported outcomes.

At three years the overall survival was high, 98.61%, but success diverged by material. Titanium implants succeeded more often than zirconia, 91.70% versus 77.78%, with survival of 100% and 97.22% respectively. The decisive difference was bone: marginal bone loss was significantly greater around zirconia implants at 36 months. Inflammatory cytokine levels showed no significant differences up to 12 months, so the bone disadvantage was not mirrored by a measurable inflammatory signal in this window.

Patient-reported outcomes captured a genuine trade-off. Patients favoured zirconia for aesthetics and the perception of cleanability, while titanium was rated superior for stability.

The conclusion is sober and clinically useful. Within the limits of a split-mouth design, zirconia implants showed reduced success and inferior marginal bone stability compared with titanium in the overdenture indication. Zirconia remains a legitimate option where patients prioritize aesthetics or metal avoidance, but it demands careful case selection and close follow-up rather than being treated as an equivalent default to titanium.