歯科インプラント周囲骨微細構造の経時的変化の比較研究 Comparative Study of Longitudinal Changes in Peri-implant Bone Microstructure

Access this Article

Search this Article

Author(s)

Abstract

目的:歯科インプラントに加わる荷重は顎骨に直接伝達され,内部骨梁のリモデリングに関与していると考えられている.しかしながら,荷重時の経時的変化と骨梁構造の再配列に関する研究は少ない.この研究は,マイクロCT を用いてイヌ顎骨内部構造の天然歯植立時,抜歯後,インプラント埋入後における経時的変化を明らかにすることを目的とした.<br/>方法:試料は,16体の雄性ビーグル犬から採取した上顎骨を用いた.まず,上顎の歯がすべて生えそろっている4頭をコントロールグループとした.次に12頭に対して両側上顎第四前臼歯,第一,第二後臼歯の合計6歯抜歯手術を行った.そして抜歯後3カ月が経過した時点で,4頭を安楽死させた.残りの8頭に対し,左側抜歯部位に3本のインプラント埋入手術を行い,3カ月後に上部構造を装着した.上部構造装着後3カ月が経過した時点で4頭を安楽死させ,上部構造装着後12カ月が経過した時点で4頭を安楽死させて試料とした.得られた試料をマイクロCT にて撮像して三次元立体構築像を作製し,顎骨骨梁構造の観察と形態計測を行った.<br/>結果:顎骨骨梁構造の観察と形態計測の結果,抜歯群は海綿骨が減少し,インプラント埋入群は厚く豊富な骨梁が認められた.骨組織体積は,抜歯群とインプラント埋入群の両方における経時的な減少が認められたが,抜歯群に比べてインプラント群のほうがその割合は小さかった.<br/>結論:本研究では,インプラントを介して加わる荷重により,歯の喪失にともなう歯槽骨の吸収を抑制し,顎骨の菲薄化を防ぐ可能性が示唆された.

Purpose:The load applied to an implant is directly transmitted to the jaw and is considered to be one of the causes of remodeling of internal trabecular bones. However, the longitudinal changes during loading and the rearrangement of the trabecular bone structure are mostly unknown.The aim of this study was to clarify the changes in internal jaw bone structure longitudinally during natural tooth eruption as well as tooth extraction and post-implantation periods in a dog model by micro computed tomography (micro-CT).<br/>Materials and Methods:Maxillae of 16 male beagle dogs were used in this study. First, 4 dogs with all maxillary molar teeth erupted were euthanized as a control group. Next, 6 teeth consisting of the bilateral maxillary fourth premolars, and first and second molars were extracted from each of the 12 dogs. Then, 4 dogs of the tooth-extracted group were euthanized 3 months after extraction of the teeth. At this time, three implants were inserted in the left side of the maxilla of the remaining 8 dogs, and the superstructures were placed after 3 months. Four of these 8 dogs with implants were euthanized at 3 months and the other 4 at 1 year after placement of the superstructure. Then, the maxillary bone was removed from each dog as a specimen and sequential micro-CT images were taken. After reconstruction of three-dimensional images, morphological and metrical observation of the jaw trabecular bone structure was performed.<br/>Results:A decrease of the trabecular bone in the tooth-extracted group was morphologically and morphometrically observed, whereas the implanted group showed thick, rich trabecular bone. Although a longitudinal decrease in the bone tissue volume was recognized both in the tooth-extracted and the implanted groups, the amount was smaller in the implanted group than in the tooth-extracted group.<br/>Conclusions:The results suggested that the application of load by implants in the case of tooth loss inhibits resorption of the alveolar bone and prevents thinning of the jaw.

Journal

  • Journal of Japanese Society of Oral Implantology

    Journal of Japanese Society of Oral Implantology 23(3), 450-459, 2010-09-30

    Japanese Society of Oral Implantology

References:  21

Codes

  • NII Article ID (NAID)
    10027680250
  • NII NACSIS-CAT ID (NCID)
    AN10072606
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    09146695
  • Data Source
    CJP  J-STAGE 
Page Top