All-on-4インプラント補綴における補綴フレームワーク材料、カンチレバー長、対合弓がインプラント周囲ひずみに与える影響

Effect of prosthetic framework material, cantilever length and opposing arch on peri-implant strain in an all-on-four implant prostheses.

抄録

目的:

下顎オールオンフォーインプラント支持の補綴物において、異なるタイプのアーチの拮抗力がインプラント周囲のひずみに及ぼす補綴物フレームワーク材料とカンチレバー長の影響を評価すること。

AIM: To evaluate the effect of prosthetic framework material and cantilever length on peri-implant strain in mandibular all-on-four implant-supported prostheses with different types of arch antagonist forces.

材料と方法:

熱硬化型アクリル樹脂で製作した完全無歯顎アーチを模擬した模型を用いた．アクリル模型の34,32,42,44番部位に4本のインプラントを埋入し、all-on-4インプラント埋入を模擬した。3種類の材料（コバルトクロム，ジルコニア，ポリエーテルエーテルケトン）と3種類のカンチレバー長（0 mm，15 mm，25 mm）でインプラント支持型ネジ保持式固定人工歯根を作製し，そのフレームワークの上に歪みゲージを装着した．各インプラントの頬側と舌側の位置には，模型上にひずみゲージを取り付けた．模型には，自然歯列，総義歯，麻痺性歯列を模擬した荷重を加えた．各ストレインゲージのインプラント周囲のひずみが記録された．

MATERIALS AND METHODS: Models simulating a completely edentulous mandibular arch fabricated in heat-cured acrylic resin were used. On the acrylic models, four implants were placed at regions 34, 32, 42, and 44 simulating all-on-four implant placements. Implant-supported screw-retained fixed prosthesis frameworks were fabricated using three different materials (cobalt-chromium, zirconia, and polyetheretherketone) and with three different cantilever lengths (zero mm, 15 mm, and 25 mm). Strain gauges were attached on the model at the buccal and lingual positions of each implant. Forces simulating opposing natural dentition, conventional complete denture, and the parafunctional habit were applied to the models. The peri-implant strain in each strain gauge was recorded.

結果:

RESULTS: Least peri-implant strains (67 microstrains) were observed when forces simulating conventional complete dentures were applied on the models and the highest peri-implant strains (9091 microstrains) were observed when forces simulating parafunctional habit were applied. One-way ANOVA test followed by Tukey's post hoc analysis was performed to compare the mean deformation scores between different materials at 50 N load. The level of significance [P-value] was set at P < 0.05. Tests showed significant differences between zero mm and the other types in all the different materials, and also between 1.5 x AP and 2.5 x AP for Zirconia and Peek material at P = 0.02 & P = .008, respectively. The results showed that the type of framework material, cantilever length, and occlusal forces from the opposing arch influence the peri-implant strain in the bone in all-on-four implant-supported prostheses.

結論:

インプラント支持による単一無歯顎アーチのリハビリテーションは，対合アーチの状況を考慮する必要がある．フレームワークの材質やカンチレバーの長さは、対合歯列弓からの力に応じて変更する必要があります。

CONCLUSION: Rehabilitation of a single, completely edentulous arch with implant-supported prostheses should consider the situation of the opposing arch. The choice of framework material, as well as the cantilever length, should be altered based on the forces from the opposing arch.