Effect of Remaining Periodontal Ligament on the Healing-up of the Implant Placement

Abstract

Tooth-shaped titanium implants were placed into a tooth socket with adhering periodontal ligament after extraction to examine the regeneration of periodontal tissues from remaining periodontal ligament cells. The extraction forces of the implants were measured with a materials testing machine. The mechanical strength of the peri-implant ligament increased markedly from 14 (25% of control) to 28 (68% of control) days. The implants and surrounding tissues were observed morphologically. The result showed that cementum-like hard tissues were formed on the surface of the titanium implants and there were many collagen fiber bundles between the cementum-like tissues and alveolar bone at 21 and 28 days. These findings suggest that placement of an implant into a socket with periodontal ligament leads to formation of new cementum-like hard tissues with functionally-oriented collagen bundles and development of adequate mechanical strength.

Regeneration of Periodontal Ligament for Apatite-coated Tooth-shaped Titanium Implants with and without Occlusion Using Rat Molar Model

“…The maximum load for HA+/OCLimplants was significantly higher than that of natural teeth and HA+/OCL-implants. The abrupt decrease of the maximum load seen in the load-deformation curve for the HA+/OCL+ implants indicates fracture of bony attachments at the interface of the implant 16) . In contrast, the load-deformation curve exhibited gradual decrease of the maximum load during rupture of the PDL collagen fibers in natural teeth 15) .…”

“…It was very difficult to regenerate PDL around cylindrical root form implants owing to the lack of remaining PDL tissue. On the other hand, a rat molar model, which was proposed by Miyashita 16,17) , is beneficial for regeneration of PDL around the implants because ruptured PDL remains in the extracted sockets. In the present study, three types of tooth-shaped titanium implant, namely, non-HA-coated without occlusion (HA-/OCL-), HA-coated without occlusion (HA+/OCL-), and HA-coated with occlusion (HA+/OCL+), were implanted into extracted tooth sockets with adhering PDL in the rat molar model, and the regeneration ability was examined.…”

“…Tooth-shaped titanium implants were manufactured according to previous reports with modification 16,17) . In brief, average root lengths were calculated from values of 10 extracted rat molars.…”

“…This model can also be useful for the placement of tooth-shaped artificial implants into tooth sockets after extraction. Miyashita proposed a new method for developing a dental implant with surrounding PDL using a rat molar model 16,17) . After the extraction of rat molar teeth, tooth-shaped titanium implants were immediately inserted into the extracted sockets.…”

Bone augmentation around a dental implant using demineralized bone sheet containing biologically active substances

“…Design of screw-type titanium implants Screw-type implants were manufactured according to a previous study with slight modifications (Nishimura Metals, Sabae, Japan) 18) . The implant size (1.37 mm in diameter and 2.0 mm in length) was designed to approximate the length of mesial roots and the diameter of rat maxillary first molars 19) .…”