Implant-bone Interface Remodeling Of New Type Implant

Objective: After teeth missing, the alveolar bone will be absorbed seriously, considering physiological or pathological reasons, this kind of alveolar bone aren't suitable for implant. Then how to perform implant on the patients comes to be an urging problem. The new type implant mentioned in the article, which combined the features of blade implant and cylinder-implant, has many disc frameworks on it. We hope that the bone could grow into the specially designed structure. If it really happen, the implant could decrease the chewing force .The length of new type implant is short, so it could be used for the patients whose alveolar bone were atrophic.This study is one of the trail studies on new type implant, through observing the growing condition of bone surrounding the new type implant in the dog mandible. The results of the study would be used as guidance of the clinical appliance.Methods: (1) Material treatments: Pure Titanium was manufactured into new type implant and cylinder-implant, the number of each type was 24.(2) Experimental animal: Six adult dogs were used , body weight of each dog was 20-25kg, they were randomly separated into three groups, adopted the methods of own control. All the premolars had been respectively extracted from the both sides of mandible , three months later, the new type implant and the cylinder-implant were implanted into the bilateral mandibular sites. (3) Specimen preparation: The dogs were sacrificed by steps. Super-rigidity slices stained with toluidine blue and sections stained with masson for histological examination were used to observe the implant-bone interface remodeling.Results: (1)General observation: All experimental animals were no postoperative inflammation and no sudden death happened. Check up the stability of the implant regularly, the implant stabilization of each stage were very well .The gingiva around the implant was no flare, and the color and texture of gingiva showed no abnormality. On probing, here was non-haemorrhage, and no obvious periodontal pocket around the implant was observed. (2)X-ray check: Radiograph of the both type implants at 4 weeks after surgery. Experimental group: Some disc frameworks of the new type implant were filled with low-density image of bone tissue, the implant-bone interface was of no transmission shadow, the image of cortical bone at the collar crest of ridge which around the implant was not clear. Control group: The low density image could be seen around the implant, and the bone near the neck of the implant was absorbed slightly. The image of cortical bone at the collar crest of ridge around the implant was not clear. Radiograph of both type implants at 8 weeks after surgery. Experimental group: all of the disc frameworks of new type implant were filled with bone, the image of the bone density increased compared with that of the 4 weeks groups, the image of cortical bone at the collar crest of ridge which around the implant are not clear. Control group: the density of the bone image around the implant increased compared with that of the 8 weeks groups. Radiograph of the both type implants at 12 weeks after surgery. Experimental group: all the disc frameworks of new type implant were filled with bone, and the implant-bone interface was osseo-integrated. Control group: the density of the bone around the implant increased compared with that of the 12 weeks groups. (3)The results observed by light microscopy showed as follows: At 4 weeks, the implant-bone interface of the both type implant was very well, new ossein, at some part of the areas, was stained with light blue color, this indicated the new bone was born, there was no inflammation at the interface, the osteoclasts were seen occasionally, and there were a lot of cells, fine blood vessels and some collagenous fiber tissues at the interface. At 8 weeks, bone collagenous fiber tissue, bone fossa, bone trabecula and some osteoblast around the bone trabecula were seen at both type implant interface. At 12 weeks, there were some bone trabecula at the cylinder-implant-bone interface, and the number of cells and fine blood vessels were less than that of the 8 weeks. The bone tissue could be seen around the new type implant, and the bone tissue grown into the disc frameworks of new type implant, no fiber tissue was observed. (4)The result of Super-rigidity slices: At 4 weeks , surrounding the implant-bone interface of the both type implant ,there were some cicatricial mass and new blood vessels formed around the implant , a few of osteoblasts were stained with prunosus . At 8 weeks, fibrous tissue did not exist at the implant-bone interface of the both type of the implant. The implant-bone interface was osseo-integrate. At 12 weeks, the implant-bone interface of the both type implant was completely osseo-integrated, there was no gap between the implant and bone.Conclusion: Both type implant could obtain synosteosis, although the new type implant had larger surface area than that of the cylinder-implant, new type implant had larger areas contacted with bone than that of the cylinder-implant. The initial stability of new type implant was quite well, in the animal experiment, we could saw the interface of new type implant and bone were almost osseo-integration at 8 weeks, and at 12 weeks, the density of new bone, which between the new type implant and the bone was similar with the alveolar bone, and the study was very important to the early loading of the new type implant in clinic.