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Evaluation of a new titanium-zirconium dental implant: a biomechanical and histological comparative study in the mini pig.

BACKGROUND
Titanium zirconium alloy with 13-17% zirconium (TiZr1317) shows significantly better mechanical attributes than pure Ti with respect to elongation and fatigue strength. This material may be suitable for thin implants and implant components exposed to high mechanical constraints.


PURPOSE
The aim of this study was to test the hypothesis that TiZr1317 and Ti implants show comparable osseointegration and stability.


MATERIALS AND METHODS
The mandibular premolars (P1, P2, P3) and the first molar (M1) in 12 adult miniature pigs were extracted 3 months prior to the study. Six specially designed implants made from Ti (commercially pure, Grade 4) or TiZr1317 (Roxolid®, Institut Straumann AG, Basel, Switzerland) with a hydrophilic sandblasted and acid-etched (SLActive, Institut Straumann AG, Basel, Switzerland) surface were placed in each mandible; three standard implants modified for evaluation of removal torque (RT) in one side and three bone-chamber implants for histologic observations in the contralateral side. RT tests were performed after 4 weeks when also the bone chamber implants and surrounding tissue were biopsied for histologic analyses in ground sections.


RESULTS
The RT results indicated significantly higher stability (p=0.013) for TiZr1317 (230.9±22.4Ncm) than for Ti implants (204.7±24.0Ncm). The histology showed similar osteoconductive properties for both implant types. Histomorphometric measurements showed a statistically significant higher (p=0.023) bone area within the chamber for the TiZr1317 implants (45.5±13.2%) than did the Ti implants (40.2±15.2%). No difference was observed concerning the bone to implant contact between the groups with 72.3±20.5% for Ti and 70.2±17.3% for TiZr1317 implants.


CONCLUSION
It is concluded that the TiZr1317 implant with a hydrophilic sandblasted and acid-etched surface showed similar or even stronger bone tissue responses than the Ti control implant.