Kazuki Shimada

Bond Strength to Dentin Subjected to Temporary Cementation of Resin Based Luting Agents

目的: リン酸を表面処理剤とするレジン系装着材料の仮着した象牙質に対する接着強さの影響を明らかにするために, 比較検討を行った.方法: HY-Bond Temporary Cement Hard (以下HYB), Freegenol Temporary Pack (以下FTP) およびNeodyne T (以下NDT) の3種類の仮着材で, レジンプレートを牛歯象牙質に仮着した.Variolink II (以下V2) およびRely X ARC (以下RX) を用いて, IPS Empressを接着して勢断接着試験用試料を作製した.仮着を行っていないものをコントロール (以下CON) とした.仮着した象牙質およびIPS Empressに対する表面処理は, 製造者指示に従って行った.試料を37℃ で24時間精製水中保管後, 勇断接着強さを測定した.結果: V2の接着強さは, CON (11.4MPa, a, b), HYB (12.7MPa, a), FTP (7.6MPa, b, c) およびNDT (5.9MPa, c) であった.CONと比較してNDTが有意に (P<0.05) 低い値を示したが, HYBおよびFTPでは有意差が認められなかった.一方, RXの接着強さは, CON (21.7 MPa, d), HYB (11.3MPa, e), FTP (6.0MPa, f) およびNDT (11.2MPa, e) であった.CONと比較してすべての仮着材で有意に低い値を示した.最も低い値を示したFTPでは, CONの27.5%であった.同一文字は多重比較において危険率5%で有意差がないことを示す.結論: V2とRXは, 接着強さが低下した仮着材がそれぞれで異なったことから, リン酸処理を行うレジン系装着材料の接着強さは, 組合せによって影響が異なることが明らかとなった.

A Study on Repair Restoration with High Filler Containing Indirect Composites-Surface Treatment for Light Cured Type Resins-

目的: 光重合タイプの高フィラー型硬質レジンの補修時における有効な表面処理方法を知ることを目的とした.方法: ArtglassおよびGradia (エナメル色ペーストAEおよびGE, デンチン色ペーストADおよびGD) を用い, 製造者指示に従い重合した被着体 (2×2×12.5mm) に, 処理なし (NT), シラン処理 (S), ボンディング処理 (B), シラン処理とボンディング処理を併用 (SB) の4条件で表面処理を行った.追加築盛は, 直接法および間接法のそれぞれで, 製造者指示の補修用レジンを用いて曲げ接着試験用試験体 (2×2×25mm) を重合して作製した.試験体は, 37℃ で24時間水中保管後に3点曲げ試験を行い, 曲げ接着強さを得た.結果: 被着体AEは直接法ではSB>S>B>NT, 間接法ではSB≧S>B>NTの順で, 被着体ADは直接法および間接法の両者で, SB>S>B>NTの順で有意に大きな曲げ接着強さを示した.一方, 被着体GEは, 直接法ではSB>B≧S>NT, 間接法ではSB≧S≧B>NTの順で, 被着体GDは, 直接法ではSB≧B>S>NT, 間接法ではSB≧B≧S>NTの順で有意に大きな曲げ接着強さを示した.結論: 最適な表面処理は, AEが直接法でSB, 間接法でSBおよびS, ADが直接法および間接法の両者でSB, GEが直接法ではSB, GDがSBおよびB, GEおよびGDともに間接法ではS, BおよびSBであった.

Chromatic Study of IPS Empress. The Effect of Various Adhesive Resin Cements on Layering Technique.

IPS Empress® is an all-ceramic crown system which provides a color tone and light transmittance resembling those of natural teeth. However, because of the translucency of all-ceramic crowns, the color of the adhesive resin cements and the abutment teeth can affect the color of the final crowns.This study examined the effects of IPS Empress® on the layering technique and color of the adhesive resin cements on various background color by comparison and examination.The color difference from the standard color was calculated, and it was judged to have color appearance when ΔE*ab≤2.0.The conclusions were as follows:1. For A 2 background, the color appearance to standard color were obtained using translucent type cements VW and VB (Variolink).2. For Au background, the color appearance to standard color were all of translucent type cements, while for Pd background, opaque type cements YO (Variolink) insertion with better color appearance.3. For H background, using translucent type cements Tr (LA cement) containing dentin color tone and opaque type cements VO (Variolink) with lower values of lightness yielded ΔE*ab≤2.0 with color appearance.The above results suggested that appropriate intermediate cements used in the layering techniqueof IPS Empress® decrease the influence of the background color, achieving a color tone approximating the target color.

Influence of Changes in the Powder Particle Size Distribution on the Physical Properties of Luting Agents. Mainly on Influence of Pretreatments of Abutment Tooth before Final Cementation.

Our department has been researching the influences of changes in particle size distribution on the physical properties of luting agents. It is said that luting agents are largely affected by contact with water. In the present study, changes in the physical properties after contact with water at the time of cementation were determined in several types of glass-ionomer cement for Luting (Gcement), which differed in particle size distribution, by using an ivory or agar jig. The physical properties of G cement were also examined after pretreatment of the abutment tooth with a surfacetreatment agent and a temporary cement inside the ivory jig.As a result, the greater the content of fine particles was, the greater the compressive strenght, tensile strength and scratch hardness of G cement tended to be. G cement containing high proportions of fine particles was not likely to be affected by water. Pretreatment suchas temporary cementation or surface-treatment prior to cementation for crown or bridge formation was found to be effective for preventing deterioration of the physical properties of G cement.