鋳造修復物下のマージナルリーケージに及ぼすキャビティライニングの影響．

[Influence of cavity lining on marginal leakage beneath cast restoration].

抄録

目的:

鋳造修復物のマージナルリーケージに及ぼすライニングの影響について検討した。

PURPOSE: This study investigated the effect of a cavity lining on marginal leakage of a cast restoration.

方法:

ヒト上顎第三大臼歯にMOD窩洞を作製した。軸方向壁面に深在性う蝕を模擬した半球状窩洞（直径1.6 mm）を作製し，グラスアイオノマー，レジン添加型グラスアイオノマー，低粘性コンポジットを含むライニング材で修復し，ライニング群として扱った．メタルインレーは12%Au-Ag-Pd合金で鋳造し，リン酸亜鉛（HZ），従来型グラスアイオノマー（FI），樹脂添加型グラスアイオノマー（VL），接着性樹脂（SB）の4種類の合着材で合着した．試験片を37°C蒸留水中に24時間保管し，5,000回のサーモサイクルを行った後，2%エリスロシン溶液に24時間浸漬して色素浸透性を評価した．中央部に同サイズの球状空洞を有するデンチンディスクに，同じ溶着剤で金属ディスクを溶着した．ライニングした試料とライニングしていない試料について，同じ保管およびサーモサイクル工程を経て，せん断接着強さを評価した．

METHODS: MOD cavities were prepared on human extracted upper third molars. Additional hemispherical cavities (1.6 mm diameter), simulating deep caries, were prepared on axial walls, and they were restored with lining materials including a glass-ionomer, a resin-modified glass-ionomer, and a low viscosity composite for a lined group. Metal inlays were cast with a 12% Au-Ag-Pd alloy and luted with four luting agents including a zinc phosphate(HZ), a conventional glass ionomer (FI), a resin-modified glass ionomer (VL), and an adhesive resin (SB). The specimens were stored in 37 degrees C distilled water for 24 hours and subjected to 5,000 thermo-cycles, and then, dye penetration was evaluated after 24 hr immersion in 2% erythrosine solution. Metal disks were luted to dentin disks, which have the same-sized spherical cavities in the central area, with the same luting agents. Shear bond strengths were evaluated for both lined and non-lined specimens after the same storing and thermo-cycle processes.

結果:

SBで合着したインレーは染料が浸透せず，HZで合着したインレーは染料が歯髄室まで浸透していた．FIおよびVLで作製されたインレーは，中程度の染料浸透性を示し，空洞作製群の染料浸透性は，作製群に比べ有意に少なかった（p＜0.05）．SBおよびVLを用いた試験片のせん断接着強さは，ライニング材に大きく影響された．HZおよびFIを用いた試験片のせん断接着強さは，0 MPaであった．

RESULTS: The inlay specimens luted with SB exhibited no dye penetration, while the specimens luted with HZ presented dye penetration reaching to the pulp chamber. The specimens luted with FI and VL showed moderate dye penetration and the values of dye penetration for the cavity-lined group were significantly less compared to those for the lined group (p<0.05). The shear bond strength of the specimens luted with SB and VL was significantly affected by the lining material. The shear bond strength of the specimens luted with HZ or FI was 0 MPa.

結論:

鋳造修復物のマージナルリークは，裏装材に影響されるが，接着性レジンを用いることにより改善される．

CONCLUSIONS: The marginal leakage of a cast restoration is affected by the cavity lining but can be improved by using adhesive resin.