影响口腔高分子粘接剂内聚强度因素的探讨

A Study on the Factors Affecting Cohesion Strength of Polymeric Dental Adhesives

本文采用柠檬酸—FeCl_3混合溶液、EDTA溶液分别作为牙面处理剂,联用一种牙本质粘接剂和四种牙釉质粘接剂,将复合树脂粘接到牙本质上,通过粘接强度的测试,考察影响高分子粘接剂内聚强度的因素。研究结果制明: 1.对于牙本质粘接剂与不含填料的牙釉质粘接剂联用体系,用柠檬酸—FeCl_3混合液处理牙面后的粘接强度比用EDTA处理的低。这可能是用前者处理时铁离子以Fe^3+存在于牙面,它对粘接剂中的单体有阻聚作用而影响粘接剂的内聚强度。 2.氧气对粘接剂单体有阻聚作用。若粘接剂中含有更容易与氧气反应的还原性物质,则可降低氧气对粘接剂中单体的阻聚作用而提高粘接剂的内聚强度。 3.对于牙本质粘接剂与含填料的牙釉质粘接剂联用体系,用柠檬酸—FeCl_3混合液处理牙面后的粘接强度比用EDTA处理的高。这种差异取决于表面处理时牙面的脱钙程度和牙本质小管的开口大小。前者使牙面脱钙和牙本质小管的开口程度较大,这有利于含填料的粘接剂树脂在牙面的充分浸润和渗透。由于此联用体系含有增强的填料,其内聚强度受Fe^(3+)阻聚作用的影响较小。

Composite resins have been widely used to restore tooth decay. Because of poor adhesion to the tooth, composite resins must resort to dental adhesives to produce strong bond to the tooth. The bond strongth between a composite resin and tooth mediated by an adhesive depends on two interface strengths and three cohesion strengths. It has been proved that the key to obtaining good bond of composite resins to the tooth is strong interface strength between an adhesive and the tooth, and high cohesion stren gth of an adhesive.The purpose of this study was to investigate the factors affecting cohesion strength of the dental adhesive by means of combining a dentin bonding agent with four kinds of enamel bonding agents to bond a composite resin onto the surface of dentin pretreated by two kinds of cleansers.The cleansers used were 10-3 aqueous solution containing 10％ citric acid and 3％ ferric chloride, and 0.5MEDTA. GM containing the mixture of glutaraldehyde and hydroxyalkyl methacrylate was used as dentin bonding agent. The enamel bonding agents included. A-Clearfil Bond, containing a phosphate monomer and a sulfinate; B-PDE, containing a phosphate monomer and a sulfinate; C-Enamel Bond, containing Bis-GMA and D-Enamel New Bond, containing Bis-GMA and propanal. The chemically curable EB-Ⅱ was adopted as composite resin, and the tensile bond strength. was tested as described previously. The results showed:1. For GM/Enamel Bond combination system the bond strength obtained by pretreatment with 10-3 was lower than that with EDTA. The observations by ESCA indicated that there was 23％ iron element added on the surface of dentin pretreated by 10-3. It was considered that the iron absorbed on dentin surface existed in the form of Fe^(3+), which inhibited the polymerization of monomers in the adhesive to reduce cohesion strength of adhesive polymers.2. The bond strengths obtained by using bonding agents with reducers were higher than those without reducers. It indicated that oxygen inhibited the polymerization of adhesive monomers. If bonding agents contained reducers that could react with oxygen easily, inhibiting effect of oxygen on polymerization of adhesives could be reduced.3. For GM/PDE combination system the bond strength obtained by pretreatment with 10-3 was higher than that with EDTA. The enhancement resulted from the increased degree of surface decalcification and degree of open dentinal tubules. The dentinal tubules in pretreatment with 10-3 were opened more widely so that adhesives could easily spread on the surface and penetrate into dentinal tubules to initiate polymerization of monomers in GM.