Clinical performance of monolithic zirconia crowns on titanium–zirconium reduced‐diameter implants in the molar area: Interim data at three years of a randomized controlled trial

Abstract Aim The aim of the present study was (i) to evaluate the clinical performance of reduced‐diameter implants placed in the molar area and (ii) to test whether monolithic zirconia implant‐supported crowns lead to similar clinical outcomes compared to porcelain‐fused‐to‐metal crowns. Materials and Methods A total of 76 patients needing a single implant crown in the posterior region were recruited. All patients received a titanium–zirconium reduced‐diameter implant (Straumann Roxolid, Tissue Level, Standard Plus, diameter 3.3 mm, regular neck) randomly allocated to receive either a (1) monolithic zirconia crown (test) or (2) porcelain‐fused‐to‐metal crown (control). Implant survival, prosthetic outcomes, and patient‐reported outcomes were assessed at crown delivery and after 3 years of follow‐up. Marginal bone levels (MBL) as well as clinical parameters including probing depth (PD), bleeding on probing (BOP), and plaque levels (PCR) were also recorded. Results A total of 59 patients were available at the 3‐year follow‐up; 32 patients with a monolithic zirconia crown (TEST) and 27 patients with a porcelain‐fused‐to‐metal crown (CONTROL). 14 implants (11 implant fractures/3 aseptic losses) were lost leading to an estimated implant survival rate of 80% ± 5.1% (95% CI 70.8%–90.8%). Prosthetic complications were limited to the control group and involved minor chippings. Conclusions This type of reduced‐diameter implant to support single implant molar crowns in the molar area cannot be recommended. Monolithic zirconia crowns appear to be a viable option in the posterior region showing similar prosthetic outcomes to porcelain‐fused‐to‐metal crowns.