Early bone formation around immediately placed two-piece tissue-level zirconia implants with a modified surface: an experimental study in the miniature pig mandible

Abstract

Purpose To histologically examine early bone formation around transmucosal implants and to evaluate the influence of surface characteristics on early peri-implant bone healing using a miniature pig model. For this, commercially available dental implants with a rough zirconia (YTZP) surface were compared to surface-modified Ti control implants at 4 and 8 weeks after placement. Methods Immediately following the extraction of six mandibular premolars, 20 two-piece, tissue-level, screw-shaped YTZP implants (Patent™ Standard Zirconia Implant ø4.1 × 11 mm) with a modified rough blasted before sintering surface were inserted in four adult miniature pigs. In addition, four titanium (Ti) tissue-level implants (Straumann® Standard RN ø4.1 × 10 mm Roxolid®) with a moderate surface (SLActive®), one per animal, were placed as control implants. A histological analysis was performed on the hard tissues after 4 and 8 weeks of transmucosal healing. Results The results show a high rate of osseointegration of the test YTZP dental implants at 4 and 8 weeks following insertion. At 4 weeks, a bone-to-implant contact ratio (BIC) of 73.7% (SD ± 16.8) for the test implants (n = 10) and 58.5% for the first control implant was achieved. The second control implant had to be excluded from analysis. At 8 weeks, a BIC of 82.4% (SD ± 16.9) for the test implants (n = 9) and 93.6% (SD ± 9.1) (n = 2) for the control implant was achieved. No statistical difference was observed comparing 4 and 8 weeks YTZP data (p = 0.126). Conclusions The results indicate a predictable osseointegration of immediate zirconia implants with a modified YTZP implant surface and a high degree of BIC present at 4 weeks following insertion. After 8 weeks of healing both the zirconia implants and the Ti implants show a BIC indicating full osseointegration. Further studies involving a larger sample size with more time points are needed to confirm these results.

Animal Models for Investigating Osseointegration: An Overview of Implant Research over the Last Three Decades

“…The bone-regeneration capacity of minipigs is nearly identical to ours, with humans recovering 1.0-1.5 mm per day and minipigs recovering 1.2-1.5 mm per day [66]. As a result, such a model has been widely used to evaluate the effect of implant geometry and surfaces on new crestal bone formation and bone-implant contact [67], as well as the new implant surfaces and immediate loading [68][69][70].…”

“…The operative protocol is general anesthesia with Zoletil 100 (tiletamine hydrochloride + Zolazepam hydrochloride) induction at 6 mg/kg IM dosage and maintenance with isoflurane at 2/2.5% in Oxygen. effect of implant geometry and surfaces on new crestal bone formation and bone-implant contact [67], as well as the new implant surfaces and immediate loading [68][69][70]. Furthermore, minipigs have been recommended as an alternative to canine models, which are fraught with ethical and controversial concerns.…”

Zirconia dental implants as a different alternative to titanium: A literature review

“…The findings indicate that after 4 weeks, the immediate zirconia implants with a modified YTZP surface exhibited favorable osseointegration and a high level of bone-to-implant contact. [ 11 ] Another study conducted on miniature pigs produced similar results in terms of direct bone contact between zirconia and titanium surface structures. Histomorphometric measurements of bone-implant contact indicated slightly better results for the titanium implant surface, although no statistically significant difference was found between these materials.…”

“…Regarding osseointegration, the reviewed studies consistently demonstrate that zirconium implants exhibit optimal osseointegration comparable to titanium implants. [ 5 11 , 19 20 21 ]…”

“…[ 7 ] Furthermore, the investigation revealed that both commercial and novel titanium-based binary alloys demonstrated no statistically significant cytotoxicity. [ 8 9 10 11 ]…”