Zirconia versus Titanium Implants: 8-Year Follow-Up in a Patient Cohort Contrasted with Histological Evidence from a Preclinical Animal Model

Abstract

Zirconia ceramic (ZC) implants are becoming more common, but comparisons between preclinical histology and long-term clinical trials are rare. This investigation comprised (1) 8-year clinical follow-up of one-piece ZC or titanium (Ti) implants supporting full overdentures and (2) histomorphometric analysis of the same implants in an animal model, comparing implants with various surface treatments. Methods: (1) Clinical trial: 24 completely edentulous participants (2 groups of N = 12) received 7 implants (one-piece ball-abutment ZC or Ti; maxilla N = 4, mandible N = 3) restored with implant overdentures. Outcomes after 8-years included survival, peri-implant bone levels, soft-tissue responses, and prosthodontic issues. (2) Preclinical trial: 10 New Zealand sheep received 4 implants bilaterally in the femoral condyle: Southern Implants ZC or Ti one-piece implants, identical to the clinical trial, and controls: Southern ITC® two-piece implants with the same surface or Nobel (NBC) anodised (TiUnite™) surface. %Bone-implant contact (%BIC) was measured after 12 weeks of unloaded healing. Results: 8 of 24 participants (33%) of an average age of 75 ± 8 years were recalled; 21% of original participants had died, and 46% could not be contacted. 80.4% of implants survived; excluding palatal sites, 87.5% of Ti and 79% of ZC implants survived. All failed implants were in the maxilla. Three ZC implants had fractured. Bone loss was similar for Ti vs. ZC; pocket depths (p = 0.04) and attachment levels (p = 0.02) were greater for Ti than ZC implants. (1.7 ± 1.6 mm vs. 1.6 ± 1.3 mm). All implants in sheep femurs survived. %BIC was not statistically different for one-piece blasted surface Ti (80 ± 19%) versus ZC (76 ± 20%) or ITC® (75 ± 16 mm); NBC had significantly higher %BIC than ITC (84 ± 17%, p = 0.4). Conclusion: Short-term preclinical results for ZC and Ti one-piece implants showed excellent bone-implant contact in unloaded femoral sites. This differed from the long-term clinical results in older-aged, edentulous participants. While ZC and Ti implants showed equivalent performance, the risks of peri-implantitis and implant loss in older, completely edentulous patients remain a significant factor.

Enhanced bioactivity and hydrothermal aging resistance of Y‐TZP ceramics for dental implant

“…Admittedly, a rough surface is more conducive to cell adhesion and spreading. Still, surface abrasion or corrosion causes phase change and microcracks, which impair the mechanical properties of Y‐TZP 12,13 . Therefore, scientists gradually recognized that the grain structure of Y‐TZP should be maintained, while the function of promoting cell growth should be achieved by adding bioactive substances.…”

“…Still, surface abrasion or corrosion causes phase change and microcracks, which impair the mechanical properties of Y-TZP. 12,13 Therefore, scientists gradually recognized that the grain structure of Y-TZP should be maintained, while the function of promoting cell growth should be achieved by adding bioactive substances. It is a common and effective way to introduce bioactive substances, mainly inorganic bioactive substances, such as hydroxyapatite (HAp, Ca 10 (PO 4 ) 6 (OH) 2 ), [14][15][16] and bioactive glass (BG), 17,18 to Y-TZP.…”