影响口腔高分子粘接剂内聚强度因素的探讨

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。     

改性牙本质粘接剂对抗变形链球菌的性能

背景：研究证实粘接修复技术治疗龋病过程中,龋洞预备后残留的细菌可在牙体组织与修复体之间继续生存较长时间,诱发继发龋或牙髓的慢性炎症。 目的：评价经甲基丙烯酰氧十二烷基溴吡单体改性树脂基粘接剂对变形链球菌的抗菌性能。 方法：制备含质量分数0(阴性对照),1%,2%,3%,4%甲基丙烯酰氧十二烷基溴吡抗菌单体的实验性GLUMA Comfort Bond粘接剂样本,以Clearfil Protect bond粘接剂为阳性对照;分别涂布在复合树脂试件表面并固化,在变形链球菌液体培养基中进行培养,培养18 h后检测菌液的A值、pH值。 结果与结论：GLUMA Comfort Bond粘接剂对变形链球菌生长及产酸能力无明显抑制作用,Clearfil Protect bond粘接剂对变形链球菌生长及产酸能力有明显抑制作用。含1%,2%甲基丙烯酰氧十二烷基溴吡抗菌单体的GLUMA Comfort Bond粘接剂对变形链球菌生长及产酸能力的抑制作用与阴性对照组相当(P > 0.05),含3%,4%甲基丙烯酰氧十二烷基溴吡抗菌单体的GLUMA Comfort Bond粘接剂固化后对变形链球菌生长及产酸能力的抑制作用与阳性对照组相当(P > 0.05)。表明添加了3%,4%甲基丙烯酰氧十二烷基溴吡抗菌单体的实验性抗菌粘接试件具有良好的抗菌性能。     

牙科陶瓷合金应用研究现状

本文从应用材料学角度介绍了牙科陶瓷合金的一般要求、各类合金的组成及不同成份的作用、合金与瓷结合的机制以及影响结合强度的因素，重点介绍了镍铬陶瓷合金、富钯陶瓷合金、钴铬陶瓷合金、钛及钛合金等，旨在推动我国牙科陶瓷合金的研制。     

不同牙科烤瓷合金材料诱导小鼠成纤维细胞DNA损伤的研究

研究不同牙科烤瓷合金材料诱导小鼠成纤维细胞(L929细胞)DNA的损伤情况,评价各种合金材料的遗传毒性.选择镍铬合金、钛合金、钴铬合金和金合金4种牙科烤瓷合金材料,制备4种合金材料的浸提液,用浸提液培养L929细胞.采用单细胞凝胶电泳(彗星试验)方法检测细胞DNA的损伤情况,镍铬合金和钛合金对细胞DNA损伤等级主要为重度损伤,钴铬合金组和金合金组的DNA损伤等级分别为中度损伤和轻度损伤.4种合金组彗星细胞的尾长、尾矩和Olive尾矩数值之间的差异具有统计学意义(P<0.05). 不同牙烤瓷合金材料诱导L929细胞DNA损伤的情况表现不同.金合金的遗传毒性性能优于镍铬合金、钛合金和钴铬合金,是具有良好生物学性能的牙科烤瓷合金材料.     

老年口腔疾病修复粘接材料的研究与应用

背景：随着粘接材料性能的不断提高和粘接技术的不断更新,粘接修复的临床应用日益广泛。复合树脂粘接材料对牙釉质、牙本质、陶瓷、金属和高分子的粘接以及水门汀对牙釉质、牙本质和金属的粘接已基本成为口腔疾病修复的常规治疗手段。 目的：探讨口腔修复粘接材料的研究与应用进展。 方法：检索口腔修复粘接材料相关的研究文献,检索词为“口腔修复(dental repair),粘接材料(adhesive material),口腔粘接剂(dental adhesive or dental bonding agent）,合成树脂(synthetic resin),水门汀(cement),牙釉质胶粘剂(enamel bonding agent),牙本质胶粘剂(dentin bonding agent),聚羧酸锌水门汀(zinc polycarboxylate cement),玻璃离子水门汀(glass ionomer cement),树脂改性的玻璃离子水门汀(resin-modified glass ionomer cement)”,语言分别设定为中文和英文。 结果与结论：目前在临床上被广泛使用的口腔粘接材料可分为2大类：一类为合成树脂类,另一类为水门汀类。合成树脂类粘接材料主要有牙本质粘接剂和牙釉质胶黏剂;水门汀类粘接材料主要有无机水门汀、聚羧酸锌水门汀、玻璃离子水门汀、树脂改性的玻璃离子水门汀、复合玻璃体。随着口腔医学的发展及社会人口老龄化,对于口腔材料会有更多的需求,对粘接牙体组织的新材料会有更高的要求。因此,粘接材料将处于口腔材料研究的重要地位。     

不同玷污层对4种树脂粘接系统粘接强度及粘接耐久性的影响

文题释义： 玷污层：牙体预备时由于车针的高速切割和挤压，牙本质表面形成厚1-5 μm的玷污层，它由无机物碎屑和凝固的胶原纤维碎屑组成。切割碎屑深入牙本质小管口形成管塞。磷酸酸蚀处理能够去除牙本质表面的玷污层及污物，而自酸蚀粘接剂则因为酸性较弱仅能对牙本质表面的玷污层及杂质进行部分溶解，并最终将剩余的玷污层包含在内形成混合粘接层。 甲基丙烯酰癸氧基二氢磷酸酯(10-MDP)：是一种性能优良的酸性功能单体，与羟基磷灰石反应生成的难溶性钙盐形成“纳米层状结构”，强烈吸附于牙本质表面，这一特点被认为能够增强粘接性能，并且对胶原纤维有保护作用，长期观察发现其可以提高粘接剂的耐久性。 背景：当用旋转式或手动器械处理牙表面时，在牙釉质和牙本质上由切割和磨损产生的碎片形成了玷污层。玷污层是影响牙和修复材料之间粘接的重要因素，明确玷污层对不同种类粘接剂的影响对口腔医生的临床选择与正确使用具有重要的临床意义。 目的：评价使用不同金刚砂车针预备的试件在人工唾液中存储24 h与100 d后，对4种粘接剂与牙本质粘接强度的影响。 方法：获取离体人磨牙80颗，分别进行600号碳化硅砂纸(对照)、中细粒度金刚砂车针、标准粒度金刚砂车针、粗粒度金刚砂车针4种牙本质表面处理，每种处理20颗；每种处理方法内分4个亚组，分别以两步法自酸蚀粘接剂Optibond Versa(VSA组)、一步法自酸蚀粘接剂Optibond All in One(AIO组)、通用型粘接剂Single Bond Universal(SBU组)及全酸蚀粘接剂Bond 5(GLU组)进行树脂粘接。粘接完成后，将试件置于人工唾液中37 ℃储存24 h及100 d，随后进行微拉伸强度测试，使用扫描电镜观察牙本质端断裂面，并对断裂模式进行分析。 结果与结论：①储存24 h：使用两步法粘接剂或全酸蚀粘接剂的情况下，不同表面处理组间的粘接强度比较差异无显著性意义(P > 0.05)；使用一步法粘接剂或通用型粘接剂的情况下，仅粗粒度车针组粘接强度低于砂纸组(P < 0.05)。使用砂纸或中细粒度车针的情况下，仅AIO组与VSA组粘接强度比较无差异；使用标准粒度车针的情况下，仅AIO组与VSA组、GLU组与SBU组粘接强度比较无差异(P > 0.05)；使用粗粒度车针的情况下，VSA组与AIO组、GLU组、SBU组粘接强度比较差异均有显著性意义(P < 0.05)，其余组间比较无差异(P > 0.05)；②储存100 d：使用两步法粘接剂或全酸蚀粘接剂的情况下，不同表面处理组间的粘接强度比较差异无显著性意义(P > 0.05)；使用一步法粘接剂的情况下，仅粗粒度车针组粘接强度低于砂纸组(P < 0.05)；使用通用型粘接剂的情况下，仅标准粒度车针组、粗粒度车针组粘接强度低于砂纸组(P < 0.05)。使用砂纸或中细粒度车针的情况下，仅VSA组与SBU组粘接强度无差异(P > 0.05)；使用标准粒度车针的情况下，仅SBU组与VSA组、GLU组与SBU组、GLU组与VSA组粘接强度无差异(P > 0.05)；使用粗粒度车针的情况下，仅VSA组与AIO组粘接强度无差异(P > 0.05)；③仅在使用两步法粘接剂的情况下，不同表面处理组100 d后的粘接强度与24 h比较差异有显著性意义(P < 0.05)；④与浸泡24 h相比，VSA组、SBU组、GLU组浸泡100 d后的粘接界面断裂和混合断裂比例略有增加，其中VSA组变化最大；与其他组比较，GLU组浸泡24 h与100 d的粘接界面断裂和混合断裂模式比例均超过50%；⑤结果表明，使用不同粒度车针预备产生了不同的玷污层，对一步法自酸蚀粘接剂粘接强度产生了显著影响，对两步法自酸蚀粘接剂和全酸蚀粘接剂未产生显著影响；存储时间对不同粘接剂产生了显著影响。 ORCID: 0000-0002-1639-6498(郑适泽) 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程     

类细胞膜仿生药物缓释涂层冠脉支架材料的研究

由单体2-(甲基丙烯酰氧基)乙基-2-(三甲基氨基)乙基磷酸酯(MPC)、甲基丙烯酸十八酯(SMA)、甲基丙烯酸羟丙酯(HPMA)和甲基丙烯酸(三甲氧)硅基丙酯(TSMA)合成了一种新型类细胞膜涂层材料。接触角显示聚合物/水界面向更加亲水方向转化。这种类细胞膜能防止血小板黏附,显著延长复钙化时间。将雷帕霉素作为模型药物植被药物涂层支架,动物实验表明,这种涂层支架能有效预防再狭窄的发生。     

烤瓷合金对机体细胞毒性的实验研究

目的:探讨3种口腔科常用烤瓷合金的细胞毒性。方法:分别采用四甲基偶氮唑蓝比色法(MTT法)和单细胞凝胶电泳(彗星试验)法检测3种烤瓷合金材料对小鼠成纤维细胞L929相对增殖率(RGR)的影响以及DNA的损伤情况。结果:金合金组的RGR为87.7±11.3,与钴铬合金组、对照组比较差异无统计学意义,其余各组间RGR比较差异均有统计学意义(P0.05);镍铬合金对DNA的损伤主要为严重损伤,而钴铬合金和金合金分别为中度和轻度损伤。结论:金合金材料和钴铬合金材料对RGR的影响显著小于镍铬合金,同时金合金材料所造成的DNA损伤最轻,因此,金合金材料是具有良好生物学性能的口腔科烤瓷合金材料。     

齿科修复材料耐磨性及硬度与天然牙齿的比较

背景：天然牙与牙科修复材料之间存在摩擦现象,为了防止天然牙过度磨损,同时延长修复体使用寿命,有必要了解天然牙与牙科修复材料间的摩擦学特性,选取相匹配的修复材料。 目的：比较天然牙和各种牙科修复材料的摩擦学性能及硬度。 方法：由第一作者检索2000/2010 PubMed数据(http://www.ncbi.nlm.nih.gov/PubMed)及万方数据库(http://www. wanfangdata.com.cn)有关天然牙的磨耗以及各种牙科修复材料磨耗等方面的文献,英文检索词为“enamel,dental restorative material,zirconia, wear resistance,hardness”,中文检索词为“牙釉质,口腔修复材料,氧化锆,耐磨性,硬度”。计算机初检得到46篇文献,根据纳入标准保留30篇进一步归纳总结。 结果与结论：牙釉质具有非常优良的摩擦学性能,耐磨性好,牙本质的耐磨性较差,天然牙齿在磨损过程中,牙本质一旦暴露,磨损将会加快。因此,选择耐磨性与天然牙齿相匹配的牙科修复材料至关重要。牙釉质的耐磨性明显高于复合树脂,复合树脂材料对天然牙的磨损较小,但自身耐磨性较差。随着新型树脂材料物理性能的不断提高,有些树脂材料的耐磨性已接近牙釉质。拜尔牙、热固塑料、铜基合金、钛及钛合金是较为理想的牙科修复材料。氧化锆陶瓷属于生物惰性陶瓷,具有很好的生物相容性、高强度和韧性等特点,是一种新型的牙科修复材料。     

自制钴铬烤瓷合金的金瓷结合性能

背景：在非贵金属烤瓷合金中,钴铬烤瓷合金在生物相容性、耐腐蚀性以及金属稳定性方面都优于镍铬烤瓷合金和含钛烤瓷合金,被广泛的应用于临床。 目的：通过与德国BEGO钴铬合金对比,评价自制钴铬烤瓷合金的金瓷结合性能。 方法：制作25 mm×3 mm×0.5 mm规格的德国BEGO钴铬合金与自制钴铬烤瓷合金两种合金的金属试条,分别熔附8 mm× 3 mm×1 mm的VITA MK 95瓷粉,采用三点弯曲的方法测试金瓷结合力,利用扫描电镜观察金属氧化界面。 结果与结论：加力后国产和德国BEGO钴铬合金样本随着力量的增加瓷层开裂同时完全脱落,表面成灰黑色氧化膜,无明显瓷残余;自制钴铬烤瓷合金与德国BEGO钴铬合金的金瓷结合力差异无显著性意义[(41.26±2.68), (41.35±2.59) MPa,   P > 0.05]。说明自制钴铬烤瓷合金的金瓷结合强度高于ISO所要求的基本值25 MPa,且与德国BEGO钴铬合金相比无差异,可满足临床要求。     

Nanolayering of phosphoric acid ester monomer on enamel and dentin

Following the "adhesion-decalcification" concept, specific functional monomers possess the capacity to primary chemically interact with hydroxyapatite (HAp). Such ionic bonding with synthetic HAp has been demonstrated for 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), manifest as self-assembled "nanolayering". In continuation of that basic research this study aimed to explore whether nanolayering also occurs on enamel and dentin when a 10-MDP primer is applied following a common clinical application protocol. Therefore, the interaction of an experimental 10-MDP primer and a control, commercially available, 10-MDP-based primer (Clearfil SE Bond primer (C-SE), Kuraray) with enamel and dentin was characterized by X-ray diffraction (XRD), complemented with transmission electron microscopy interfacial ultrastructural data upon their reaction with enamel and dentin. In addition, XRD was used to study the effect of the concentration of 10-MDP on nanolayering on dentin. Finally, the stability of the nanolayers was determined by measuring the bond strength to enamel and dentin when a photoinitiator was added to the experimental primer or when interfacial polymerization depended solely on the photoinitiator supplied with the subsequently applied adhesive resin. XRD confirmed nanolayering on enamel and dentin, which was significantly greater on dentin than on enamel, and also when the surface was actively rubbed with the primer. Nanolayering was also proportional to the concentration of 10-MDP in the primer. Finally, the experimental primer needed the photoinitiator to obtain a tensile bond strength to dentin comparable with that of the control C-SE primer (which also contains a photoinitiator), but not when bonded to enamel. It is concluded that self-assembled nanolayering occurs on enamel and dentin, even when following a clinically used application protocol. The lower bonding effectiveness of mild self-etch adhesives to enamel should be ascribed in part to a lower chemical reactivity (nanolayering) with enamel HAp.     

Bonding of dual-cured resin cement to zirconia ceramic using phosphate acid ester monomer and zirconate coupler

This study evaluated the shear bond strength between dual-cured resin luting cement and pure zirconium (99.9%) and industrially manufactured yttrium-oxide-partially-stabilized zirconia ceramic, and the effect of MDP (10-methacryloyloxydecyl dihydrogen phosphate) primer (MP) and zirconate coupler (ZC) on bond strength. Two different-shaped pure zirconium and zirconia ceramic specimens were untreated or treated with various primers, including different concentrations of MP containing phosphoric acid ester monomer (MDP) in ethanol, ZC containing a zirconate coupling agent in ethanol, or a mixture of MP and ZC. The specimens were then cemented together with dual-cured resin luting cement (Clapearl DC). Half of the specimens were stored in water at 37 degrees C for 24 h and the other half were thermocycled 10,000 times before shear bond strength testing. The bond strengths of resin luting cement to both the zirconium and zirconia ceramic were enhanced by the application of most MPs, ZCs, and the mixtures of MP and ZC. For the group (MP2.0+ZC1.0) containing 2.0 wt % MP and 1.0 wt % ZC, no significant difference was observed between in shear bond strength before and after thermal cycling for both zirconium and zirconia ceramic (p > 0.05). For the other primers, statistically significant differences in shear bond strength before and after thermal cycling were observed (p < 0.05). The application of the mixture of MP and ZC (MP2.0+ZC1.0) was effective for bonding between zirconia ceramic and dual-cured resin luting cement. This primer may be clinically useful as an adhesive primer for zirconia ceramic restoration.     

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction). Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm² in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mm/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin (P < 0.001). Micro-tensile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions (P < 0.001). Immediate micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements (P < 0.001). It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.     

The effects of three different desensitizing agents on the shear bond strength of composite resin bonding agents

The aim of this study was to evaluate the effects of three desensitizing agents on the shear bond strengths of four different bonding agents used to bond composite resin to dentin.A total of 160 extracted human molars were sectioned parallel to the occlusal plane under water cooling, polished and randomly divided into 4 groups of 40. Each group was treated with a different desensitizing agent (Tooth Mousse, Ultra-EZ, Cervitec Plus), except for an untreated control group. Each group was then randomly subdivided into 4 groups of 10, and a different dentin bonding agent (XP Bond, AdheSE, Adper Prompt L-pop, GBond) was applied to each group in order to bond the specimens to a resin composite (Gradia Direct) built up using a plastic apparatus. A Universal Testing Machine was used to measure the shear bond strength of each specimen. Statistical analysis was performed using one-way ANOVA and Tukey’s tests.With the exception of the Control/AdheSE and Ultra-EZ/XP Bond groups, no statistically significant differences were found in the shear bond strength values of the groups tested. These findings suggest that the use of different desensitizing agents does not affect the shear bond strength of various adhesive systems used to bond resin composite to dentin.     

Evaluation of the fatigue behavior of the resin-dentin bond with the use of different methods

The clinical performance of directly bonded resin composites is fundamentally dependent on durable adhesion to prevent gap formation over time. The goal of this investigation was to evaluate the effectiveness of various dentin adhesives by means of quasistatic and dynamic dentin bond strengths, and also to determine marginal and internal gap formation after loading in an artificial oral environment. Three hundred thirty human third molars were used within four weeks of extraction. Adhesives used were A.R.T. Bond, OptiBond FL, Scotchbond Multi-Purpose Plus, Single Bond, Prime & Bond NT, and One Up Bond F for bonding of one resin composite (Z 250). Buccal and lingual aspects of 90 teeth were ground flat to expose dentin, then resin composite cylinders were bonded. Initial bond strengths (n = 10) and adhesive fatigue limits (n = 20) were determined with the use of a shear test apparatus. One hundred eighty conical cavities were prepared into dentin discs and filled with the same materials. After 21 days of storage, initial push-out bond strengths (n = 10) and adhesive fatigue limits (n = 20) were measured. Sixty molars with MO cavities (n = 10) with margins below the cement-enamel junction were filled. Before and after thermomechanical loading (100000 x 50 N and 2500 x thermocycling between + 5 and + 55 degrees C), marginal gap formation and internal adaptation (only after loading) were analyzed under a SEM (x 200). The one-bottle systems showed higher shear bond strengths when evaluated statically and dynamically. However, cyclic fatigue push-out bond strengths resulted in higher values for older multistep systems. Marginal and internal gap analysis confirmed the results, in favor of older adhesive systems (p <.05; Mann-Whitney U test).     

Shear bond strength between titanium alloys and composite resin: sandblasting versus fluoride-gel treatment

The aim of this study was to investigate the effect of fluoride gel treatment on the bond strength between titanium alloys and composite resin, and the effect of NaF solution on the bond strength of titanium alloys. Five titanium alloys and one Co-Cr-Mo alloy were tested. Surface of the alloys were treated with three different methods; SiC polishing paper (No. 2000), sandblasting (50-microm Al2O3), and commercially available acidulated phosphate fluoride gel (F-=1.23%, pH 3.0). After treatment, surfaces of alloy were analyzed by SEM/EDXA. A cylindrical gelatin capsule was filled with a light-curable composite resin. The composite resin capsule was placed on the alloy surface after the application of bonding agent, and the composite resin was light cured for 30 s in four different directions. Shear bond strength was measured with the use of an Instron. Fluoride gel did not affect the surface properties of Co-Cr-Mo alloy and Ni-Ti alloy, but other titanium alloys were strongly affected. Alloys treated with the fluoride gel showed similar bond strengths to the alloys treated with sandblasting. Shear bond strength did not show a significant difference (p<0.05) regardless of treatment time (5, 10, and 20 min) of fluoride gel. After the ultrasonic cleaning subsequent to the fluoride-gel treatment, residues of fluoride ion or any other titanium-fluoride complexes were not detected. NaF solution did not reduce the shear bond strength of titanium alloys. To enhance the bond strength of composite resin to titanium alloys, fluoride-gel treatment may be used as an alternative technique to the sandblasting treatment.     

Effect of elapsed time following bleaching on the shear bond strength of composite resin to enamel

The purpose of this study was to investigate the effect of post-treatment time on the shear bond strength of composite resin to enamel after bleaching with 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching systems. One hundred and thirty-five flattened labial enamel surfaces obtained from human mandibular incisors were divided into two bleaching groups of 10% CP (n = 60) and 35% HP (n = 60) and a control group (n = 15). Specimens in the control group (group 1) were not bleached. Each bleaching group was then divided into four subgroups (n = 15). For both CP and HP groups, group 2 consisted of specimens bonded immediately after bleaching. In groups 3, 4, and 5, specimens were immersed in artificial saliva for 24 h, 1 week, or 2 weeks after bleaching, respectively. After the specimens were bonded with Clearfil SE Bond and Clearfil ST, they were tested in shear until failure. For both CP and HP groups, shear bond strength of composite resin to enamel that was bonded immediately after bleaching was significantly lower than that of unbleached enamel (p < 0.05). However, in CP group restored after 24 h, the bond strength returned to values close to those of nonbleached enamel (p > 0.05). It took 1 week to return to conditions that lead to control bond values for HP bleaching applications (p > 0.05). The results of this study proved that immediate bonding of composite to enamel bleached with 10% CP and 35% HP gels result in a significant decrease in shear bond strength. It is advisable that composite resin application onto bleached enamel surfaces should be delayed at least 24 h for 10% CP and 1 week for 35% HP.     

Oligomers with pendant isocyanate groups as tissue adhesives: II. Adhesion to bone and other tissues

The adhesive properties of a series of oligomers prepared from 2-isocyanatoethyl methacrylates (IEM) and/or m-isopropenyl-alpha,alpha-dimethylbenzyl isocyanate (TMI) and various acrylates or methacrylates were studied. The bond strength of bone, dentin, or soft tissue specimens joined with these oligomers respectively to bone, dental composite restorative, or denture base resin were determined by tensile adhesion or shear tests. These oligomers are more effective in forming stronger bonds to bone than are other tissue adhesives. Fracture occurs cohesively, usually within the bone. Thermocycling in water for 1 week between 5 degrees C and 55 degrees C did not decrease adhesion indicating that exposure to water or thermal shock produced no deterioration of the bond. Tensile adhesion of bovine or human dentin joined to composite restorative resin by means of the oligomers is similar to that of the best dental bonding agents such as Gluma (glutaraldehyde and 2-hydroxyethyl methacrylate) or ferric oxalate + N-phenylglycine + dimethylacryloxyethyl-pyromellitate. These oligomers also strongly bond soft tissues and calfskin and to acrylic resins and composites.     

Development of self-etching primer comprised of methacrylamide, N-methacryloyl glycine

In order to develop a more effective self-etching primer, it is helpful to understand how a functional monomer conditions the surface of the teeth.

In this study, the reactivity by the carboxylic acid in the N-methacryloyl glycine (NMGly) on the calcium phosphate in hydroxyapatite or dentin was studied. The efficacy of the NMGly as a functional monomer for a self-etching primer was then examined.

Applying NMGly to both the enamel and dentin resulted in an increase in the bond strength of resin, since the carboxylic acid in the NMGly decalcified the calcium phosphate in the hydroxyapatite and dentin. The bond strength to dentin achieved was higher than with the enamel. This difference was most likely due to different enamel and dentin adhesion mechanisms.     

Raman and IR studies on adsorption behavior of adhesive monomers in a metal primer for Au,Ag, Cu,and Cr surfaces

6-[N-(4-vinylbenzyl)propylamino]-1,3,5-triazine-2,4-dithione (VBATDT) and 10-methacryloyloxydecyl dihydrogen phosphate (M10P) are functional monomers used for the surface treatment of dental alloys. The aim of our study was to clarify the role of a commercial metal primer containing both the monomers in adhesion between resin and various dental metals on a molecular level. We used surface-enhanced Raman scattering (SERS) and infrared reflection absorption (IRA) spectroscopy. An SERS measurement was performed with a 647 nm laser line for a mixture of aqueous Au colloid and the primer. IRA spectra were taken for cast films of the primer on Au, Ag, Cu, and Cr surfaces as a function of rinse time, and for self-assembled monolayer (SAM) films from dilute mixed solution of VBATDT and M10P. These spectra indicate that VBATDT in the primer is mainly chemisorbed on Au, Ag, and Cu surfaces with respect to thickness, whereas only M10P is adsorbed on Cr. We also examined the tensile bond strengths between resin and Au, Ag, Cu, and Cr plates treated by VBATDT, with and without M10P, and found that VBATDT effectively promotes the bond strength between resin and the metals except for Cr, whereas M10P is effective only for Cr. These adhesion characteristics are consistent with the chemisorbed species on each metal surface as shown in the spectroscopic evidence.