Introduction

In recent years, osseointegrated implantology has evolved as a safe and predictable practice. The success can be attributed to the development of new geometries, and use of novel surfaces and alloys. Currently, titanium alloys, Al₂O₃-based ceramics, hydroxyapatite and zirconia are considered as biocompatible implant materials.

Aim

To analyze the impact of different implant materials or alloys on clinical outcomes in dental implant rehabilitation. 

Selection Criteria for the Included Studies

• Studies conducted in patients who required implant–prosthetic rehabilitation therapy
• Studies comparing titanium alloys/zirconia dental implants

Methods

Study Design

Outcomes

Results

• A total of 10 randomized controlled trials (RCTs) comparing zirconia and titanium dental implants across clinical and radiographic outcomes were included in the systematic review. 
• Bienz et al. evaluated 42 patients with adjacent missing teeth, each receiving one zirconia and one titanium implant. After 12 weeks, half ceased oral hygiene for 3 weeks. Plaque control index increased in both groups, favoring zirconia, while BoP was higher in titanium implants. No histological differences were observed.
• Patil et al. conducted an RCT with 24 participants (36 implants) using zirconium–titanium implants for mandibular overdentures. Bone loss and patient satisfaction were assessed at 1 month and 1 year, with no significant differences between one- and two-implant groups.
• Koller et al. studied 28 implants (14 zirconia, 14 titanium) in 21 patients over 80.9 months. No significant differences were found except BoP at 30 months, favoring zirconia (p = 0.001).
• Payer et al. followed 22 patients (31 implants) for 24 months, finding no differences in bone loss, survival, or mucosal condition between zirconia and titanium implants.
• Müller et al. evaluated 91 patients (47 completed) over 5 years comparing titanium–zirconium and titanium grade IV implants for overdentures. No significant differences in crestal bone level, success, or survival rates were noted.
• Ioannidis et al. followed 32 of 40 patients for 3 years after single-tooth restorations. No implant failures or significant differences in MBL or success rate were observed; only full-mouth plaque score favored zirconia.
• Osman et al. studied 129 implants in 24 patients. Zirconia implants had more fractures (n=3) and greater MBL; titanium showed lower failure risk in the maxilla (p < 0.0001).
• Al-Nawas conducted a split-mouth RCT (n=91), finding no differences in success, survival, or bone loss. Cannizzaro et al. reported higher failure in immediately vs. delayed placed zirconia implants (40% vs. 3%; p = 0.010).

Conclusions

• The systematic review confirmed the safety of using endosseous dental implants made from different alloys like zirconium and grade IV titanium. 
• While zirconia implants tended to show a higher average rate of marginal bone resorption over time, no significant differences were found in clinical, radiographic, or prosthetic outcomes. 
• Zirconia offered superior aesthetics, but its higher fracture risk highlights the need for further material improvements to enhance long-term reliability.

Materials (Basel). 2022 Mar 7;15(5):1979.  doi: 10.3390/ma15051979.