Osseointegration of zirconium dental implants three months after insertion in rabbit femur. Histopathological study.

Implantology is a highly researched field with a constant concern in finding and studying new implant materials. Lately, zirconium has become a very attractive alternative to the detriment of titanium, but the research results were sometimes contradictory. Thus, we considered as opportune to study the osseointegration of zirconium dental implants in rabbit femur, three months after insertion. The biological material was represented by five rabbits and the experimental protocol was approved by the Ethics Committee of the University of Oradea, Romania. The implants (zirconium ceramic dental implants: 5 mm length, 2.6 mm diameter) were inserted in the femur under controlled conditions, after creating a bone defect. The animals received the appropriate postoperative care. Three months later, the implantation area was harvested and processed for histological examination. The assessment of the osseointegration process of the zirconium implants showed that they were very well tolerated by the host organism that did not trigger any rejection processes. Approximately 80% of the compromised bone was replaced with newly formed bone in advanced stages of remodeling and consolidation. The proliferated bone near the implants acquired a structure similar to the rabbit diaphyseal bone, but with higher density and size of the osteons. The stage reached by the osseointegration process three months after the insertion of the implants, ensures a good consolidation of the implants that supports the prosthetic structures, which are to be built on them.

A micro-computed tomography study of morphological aspect of root canal instrumentation with ProTaper Next and One Shape New Generation in mandibular molars.

ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) (PTN) and One Shape New Generation (MicroMéga, Besançon, France) (OSNG) belong to a relatively new generation of rotary nickel-titanium (NiTi) files. Scientists keep improving features of endodontic files in order to obtain anatomically shaped and cleaned root canals and avoid canal transportation, for a better outcome of the endodontic treatment. For the current study, the aim was to evaluate and assess the changes in root canal morphology after instrumentation with PTN and OSNG by using micro-computed tomography (CT). This high-tech resolution tomography allows a much more detailed analysis of the root canal anatomy and its transformation after rotary instrumentation. We have selected 10 mandibular molars; before and after canal preparation, the samples were distributed in two homogeneous groups (PTN and OSNG groups) and submitted to standardized radiographs and micro-CT (SkyScan1172, Kontich, Belgium). From the three-dimensional (3D) images obtained from the scanning, we were able to perform a two-dimensional (2D) (perimeter, area and roundness), respectively a 3D (volume, surface area, structure model index) analysis, before and after root canal instrumentation. Results did not revealed important statistical differences among the two groups in relation to the curvature and volume of the root canals before instrumentation; after rotary instrumentation, there was a substantially increase of volume and surface area for all the samples (p<0.05). The two types of instruments preserved the original canal path, maintaining a continuous, safe and adequate shape and taper of the root canals.