3Dプリンターで作製した義歯床用アクリル樹脂と従来の熱硬化型および冷間硬化型の衝撃強度について

Impact strength of 3D printed and conventional heat-cured and cold-cured denture base acrylics.

抄録

目的:

3Dプリンターで作製したレジンと、従来から作製されている熱硬化型および冷間硬化型アクリル樹脂の義歯床の衝撃強度を評価し、比較すること。

PURPOSE: To evaluate and compare the impact strength of 3D-printed resin to conventionally fabricated denture bases of heat-cured and cold-cured acrylic resin.

材料および方法:

義歯床材を3群（n=25ずつ，N=75）に均等に分けた．(1) 3Dプリント材（Denture Base LP, Formlabs），(2) 熱硬化型アクリル樹脂（Lucitone 199, Dentsply Sirona），(3) 冷間硬化型アクリル樹脂（Lucitone HIPA, Dentsply Sirona）である．3Dプリントした試料は，コンピュータ支援設計（CAD）ソフトウェア（Autodesk Meshmixer）を用いて，長さ64 mm，幅12.7 mm，厚さ3.2 mmに設計し，デスクトップ型光造形プリンタ（フォーム2，フォームラボ）を用いてプリントを実施した．熱硬化型および冷間硬化型のアクリル樹脂製試験片は、従来の方法（圧縮と流し込み）で作製しました。衝撃エネルギーは衝撃試験機からジュールで直接読み取り、各試験片の断面積から衝撃強度をkJ/mで算出した。分散分析、テューキー多重比較検定、尤度比α=0.05が実施されました。

MATERIALS AND METHODS: Denture base materials were evenly divided into three groups (n = 25 each; N = 75): (1) 3Dprinted material (Denture Base LP, Formlabs); (2) Heat-cured acrylic resin (Lucitone 199, Dentsply Sirona); and (3) cold-cured acrylic resin (Lucitone HIPA, Dentsply Sirona). The 3Dprinted specimens were designed through computer-aided design (CAD) software (Autodesk Meshmixer) with the dimensions 64 mm long, 12.7 mm wide, and 3.2 mm thick, then printed with a desktop stereolithography printer (Form 2, Formlabs). Heat-cured and cold-cured acrylic resin specimens were fabricated through conventional (compression and pouring) methods. The impact energy was read directly from the impact tester in joules, and the cross-sectional area of each specimen was used to calculate the impact strength in kJ/m. Analysis of variance, Tukey multiple comparisons test, and a likelihood ratio α = .05 were conducted.

結果:

平均衝撃強度は，熱硬化型アクリル樹脂で 8.9 kJ/m，3Dプリント樹脂で 11.2 kJ/m，低温硬化型アクリル樹脂で 14.9 kJ/m であった．Tukey multiple comparisons testにより，コールドキュア群の衝撃強度は3Dプリント樹脂群および熱硬化型アクリル樹脂群に比べ有意に大きかった．

RESULTS: The average mean impact strength was 8.9 kJ/m for heat-cured acrylic resin, 11.2 kJ/m for 3D-printed resin, and 14.9 kJ/m for cold-cured acrylic resin. Tukey multiple comparisons test showed that the impact strength for the cold-cured group was significantly greater than the 3D-printed resin and heat-cured acrylic resin groups.

結論:

本研究の制約の中で，冷温硬化型アクリル樹脂（ルシトンHIPA）の衝撃強度が最も大きく，次いで3Dプリント樹脂（デンチャーベースLP），従来の熱硬化型義歯床材（ルシトン199）の順であった．

CONCLUSION: Within the limitations of this study, the cold-cured acrylic (Lucitone HIPA) showed the greatest impact strength, followed by 3D-printed resin (Denture Base LP) and conventional heat-cured denture base materials (Lucitone 199), respectively.