Tissue integration of a new titanium-zirconium dental implant : a comparative histologic and radiographic study in the canine

BACKGROUND: This study evaluates a newly developed titanium-zirconium implant (TiZr), comparing it to a commercially available pure titanium (Ti) implant subjected to the same surface treatment. METHODS: In nine dogs, 12 implants (six TiZr and six Ti) were randomly placed in the mandible with the implant shoulder at the bone crest and subjected to submerged healing. Standardized radiographs were taken after implantation, and at the sacrifice of 2 weeks (three dogs), 4 weeks (three dogs), and 8 weeks (three dogs). Histologic and histomorphometric measurements were performed on non-decalcified histologic sections. The main outcome measures included the first bone-implant contact (fBIC) and BIC over time. For statistical analysis, Wilcoxon signed-rank test and mixed model regressions were applied. RESULTS: From baseline to 8 weeks, a mean bone loss of 0.09 +/- 0.33 mm for TiZr and a gain of 0.02 +/- 0.33 mm for Ti were calculated radiographically. The number of implants with the fBIC coronal to the reference point (implant shoulder) gradually increased over time, reaching 39% of all TiZr implants and 50% of all Ti implants at 8 weeks. The mean fBIC values for Ti and TiZr were 0.29 +/- 0.42 mm and 0.26 +/- 0.32 mm (2 weeks), -0.01 +/- 0.20 mm and 0.10 +/- 0.28 mm (4 weeks), and -0.06 +/- 0.22 mm and 0.08 +/- 0.30 mm (8 weeks), respectively. The mean BIC values peaked at 86.9% +/- 6.8% (8 weeks) for TiZr and at 83.4% +/- 5.9% (4 weeks) for Ti. No statistically significant differences were observed at any time point. CONCLUSION: TiZr and Ti bone level implants with chemically-modified, sandblasted, and acid-etched surfaces performed similarly in regards to osseointegration in this unloaded canine study