A Histological Study on Tissue Responses to Titanium Implantation in Rat Maxilla: The Process of Epithelial Regeneration and Bone Reaction

Abstract

The present study aimed to establish a titanium implantation model using rat maxillae as well as demonstrate the chronological tissue responses to implantation. Pure titanium implants were inserted in the upper first molar extraction sites of Wistar rats 1 month after tooth extraction. The animals were sacrificed at 1 to 30 days postimplantation, and prepared tissue specimens were processed for light microscopy. The removal of implants from tissue blocks was done using 2 methods: mechanical removal or a cryofracture technique. In the early stages, peri-implant tissues showed severe damage to the oral epithelium and collagen bundles with significant inflammatory cell infiltration. The peri-implant epithelium grew apically along the implant by 10 days postimplantation, and regenerated to show a similar feature of junctional epithelium seen in normal rats at 15 days postimplantation, at which time no signs of inflammation were observed. The regenerated collagen bundles in the connective tissue were arranged circumferentially to the implants in the horizontal sections. New bone formation first appeared around the implants at 5 days postimplantation, covering the entire perimeter of implants by 30 days postimplantation. Scanning electron microscopic observations of the surface texture of the removed implants suggest the probability of an adhesive mechanism between the implants and the peri-implant epithelium and/or the alveolar bone. These findings indicate that this experimental model is useful for detailed analysis of peri-implant tissue because of its easy implantation procedure.

Effect of chronic stress on implant osseointegration into rat's mandible

“…The test group subjected to the stress trials exhibited a delay in repair process, an increased inflammatory infiltrate, a lower BIC surface area, and a lower BA formed within the limits of the implant threads at 18 days. The results observed at 33 days, there was newly formed bone in both groups, with no significant differences 9 .…”

“…The experimental time used in this paper were chosen for fetching, as the described hypothesis, an understanding aboust the effect of chronic stress on the osseointegration in a period in which the bone is still maturation bone (18 days) 1,9 9,1 and other already mature (33 days) 9 18 and 33 days and weight difference at 18 and 33 days (n=7). *Statistically significant difference (p<0.05) between the amount of cortisol hormone during the 18 day experimental period for the CG and SG.…”

“…The size of the implants in the literature was 1.15mm in diameter and 3mm in length 9,12 . When contacted, the manufacturer revealed that implants with the above-cited diameters could not have been subjected to surface treatment.…”

“…Therefore, the present study aimed to elucidate the process at two stages of osseointegration, one at 18 days, halfway through the cycle of alveolar bone formation in rats 9 , and the other at 33 days, in newly formed bone 10 . The purpose of this investigation was to compare dental implant osseointegration into the mandible of rats submitted to the effect of chronic stress with that in the mandible of rats not submitted to such stress.…”

Characterization of the peri-implant epithelium in hamster palatine mucosa: Behavior of Merkel cells and nerve endings

“…IS: implant space (1, 3, 17, 19, 21, 23, 24, 26, 30, 31). The morphology of Merkel cells in the oral cavity has been investigated in humans and in rats (1,26), and there have been a few reports on Merkel cells in the touch domes of the hamster cheek pouch (5,30). In addition, the relationship between nerve fibers and Merkel cells has also been reported (21,23).…”