抄録
The progress of patients treated with the 2-piece hydroxyapatite implant (Apaceram® 2-Piece Implant, Pentax, Tokyo, Japan) in our clinic has been followed regularly by a standardized radiograph and digital image processing. The radiological examination, which has been demonstrated in this journal by us, is useful for evaluating quantitative bone changes after the implant placement. We observed chronological changes of both marginal bone height and bone density around the implant about two years after the implant placement.33 Apaceram implants were placed in the mandibular molar regions in 13 patients. The mean follow-up period was three years.
1. With regard to chronological changes of marginal bone height, the radiographic results were divided into three groups:type I in which the position remained constant or increased with time course, type II in which the position decreased gradually after the superstructure placement, and type III in which the position decreased rapidly after the abutment placement. The mean changes of the bone height in the Groups I, II, and III amounted to 0.1 mm, -0.4, and -2.4 mm/year, respectively.
2. Bone density around successful Apaceram implant increased clearly. The aspect looked like the bird wing between the implant. The degree of bone change during several months after the abutment placement was larger than that of both during one year after the period and during 6 months after the fixture placement. The lower preoperative bone density was, the more bone density increased.
We evaluated the above results as radiological examination for two years after the implant placement. Our results indicated that the bone resorption/formation around the implant might be related in the occlusal force, and adequate occlusal force should be produced on the implant during each phase following the implant placement.
