Wang Yong, Spencer Paulette, Hager Christy, Bohaty Brenda
Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City 650 E. 25th St., Kansas City, MO 64108, USA.
J Dent. 2006 Jan;34(1):26-34. doi: 10.1016/j.jdent.2005.03.004.
A primary reason for premature failure of Class II composite restorations is recurrent decay at the gingival margin. The integrity of the gingival margin depends on the bond formed with dentine. Using scanning electron microscopy (SEM) and histomorphologic technique, the purpose of this study was to characterise the adhesive/dentine (a/d) bond in dentine sections from the dentinoenamel junction (DEJ) and the cementoenamel junction (CEJ) with commercial adhesives of varying hydrophobic/hydrophilic composition.
The occlusal 1/3 of the crown was removed from 20 human third molars, this exposed the surface used for the DEJ sections. The teeth were sectioned occluso-gingivally into equal halves: one-half representing the DEJ; the remaining half was sectioned 4mm deep to the exposed surface (CEJ). Each half was treated with the same adhesive. The teeth were randomly selected for treatment with Single Bond (SB, 3M) or Dentastic UNO (UNO, Pulpdent) using wet bonding technique as per manufacturers' instructions. Thin (3-5mum) sections of native a/d interfaces were cut and stained with Goldner's trichrome for light microscopic (LM) examination. Companion slabs were polished and acid-bleach treated, then analysed with SEM.
DEJ sections: SB/dentine specimens had approximately 4mum exposed protein at the interface, UNO infiltrated the depth of the demineralised dentine and encapsulated exposed protein. CEJ sections: SB/dentine specimens had highly variable interface structure with localized exposed protein, UNO/dentine exhibited 3-5mum exposed protein at the interface. The quality of the interface was exaggerated and the above differences were not revealed based on SEM characterisation.
As a result of adhesive phase separation, SB does not form structurally integrated a/d bonds at the DEJ or CEJ. The increased hydrophilic composition of UNO contributes to the formation of an integrated a/d bond at the DEJ, but structural differences and increased moisture leads to unprotected protein at the a/d interface in the CEJ sections. The inability of the SEM technique to reveal the complexity of the interface could be related to the modifications of the a/d interface caused by polishing and acid-bleach treatment.
II类复合树脂修复体过早失败的一个主要原因是龈缘处的继发龋。龈缘的完整性取决于与牙本质形成的粘结。本研究的目的是使用扫描电子显微镜（SEM）和组织形态学技术，对来自牙釉质牙本质界（DEJ）和牙骨质牙釉质界（CEJ）的牙本质切片中，使用不同疏水/亲水成分的商用粘结剂形成的粘结剂/牙本质（a/d）粘结进行特征描述。
从20颗人类第三磨牙上移除牙冠的咬合面1/3，这暴露出用于制作DEJ切片的表面。将牙齿沿咬合面-龈向切成相等的两半：一半代表DEJ；另一半向暴露表面切4mm深（CEJ）。每一半都用相同的粘结剂处理。按照制造商的说明，使用湿粘结技术，随机选择牙齿用单键粘结剂（SB，3M）或Dentastic UNO（UNO，Pulpdent）进行处理。切取天然a/d界面的薄（3 - 5μm）切片，用Goldner三色染色法进行光镜（LM）检查。制作配套的切片，进行抛光和酸漂白处理，然后用SEM分析。
DEJ切片：SB/牙本质标本在界面处有大约4μm暴露的蛋白，UNO渗透到脱矿牙本质的深度并包裹暴露的蛋白。CEJ切片：SB/牙本质标本的界面结构高度可变，有局部暴露的蛋白，UNO/牙本质在界面处有3 - 5μm暴露的蛋白。基于SEM表征，界面质量被夸大，上述差异未被揭示。
由于粘结剂相分离，SB在DEJ或CEJ处不能形成结构完整的a/d粘结。UNO增加的亲水成分有助于在DEJ处形成完整的a/d粘结，但结构差异和水分增加导致CEJ切片的a/d界面处有未受保护的蛋白。SEM技术无法揭示界面的复杂性可能与抛光和酸漂白处理对a/d界面的改变有关。
