This study was designed to evaluate the in vivo affinity of titanium and stainless steel materials, the clinical use of which has remarkably increased recently, by observing the time course of tissue reactions such as reconstruction of the microvascular network in the periosteal tissue adjacent to materials implanted just be neath the mandibular periosteum in rabbits.
In this study, we used as control rabbit mandibular periosteum that had been repositioned and sutured after separation. A titanium plate and stainless plate were implanted between the mandibular periosteum and cortex. The reconstruction process of the microvascular network of the mandibular periosteum adjacent to the metal was observed over time via resin blood vessel models under scanning electron microscopy.
The results showed that microvascular reconstruction in the control mandibular periosteum was almost complet, with findings comparable to those of normal mandibular periosteum after seven days of vascular repair, which began 24 hours after injury. After titanium plate implantation, reconstruction began with repair of the outer layer in 72 hours, followed seven days later by repair of the vascular network in the inner layer. Thirty days later, reconsruction was comparable to that in the normal mandibular periosteum. In contrast, reconstruction of the microvscular network of the mandibular periosteum after stainless steel plate inplantation showed a different course. Coarse outer vascularization was noted after 30 days in the absence of inner vascular repair, although outer vascular repair had been observed seven days after metal plate implantation. These results led to the following conclusions:
1. Titanium apparently did not interfere with vascularization factors or obstruct physiological functions of the periosteum, because reconstruction of the microvascular network was observed in the mandibular periosteum exposed to the titanium plate along with signs suggestive of osteoblasts.
2. The microvascular network of the mandibular periosteum that came into contact with the stainless steel plate failed to be reconstructed and scar tissue remained. These findings suggested that vascularization factors were inhibited without recovery of the physiological function of the periosteun.
