超声洁治术对金属烤瓷冠边缘微渗漏的影响

目的探讨超声洁治术对金属烤瓷冠边缘微渗漏的影响。方法选取离体磨牙70颗,随机分成7组（A—G组）,每组10颗,按烤瓷冠要求常规牙体预备,制作钴铬合金烤瓷冠。A、B组应用聚羧酸锌水门汀粘结;C、D组应用玻璃离子水门汀粘结;E、F、G组应用树脂粘结剂粘结。各组经冷热循环实验后,B、D、F组按要求进行单次超声洁治术;G组进行3次超声洁治术;A、c、E组作为对照组,不进行超声洁治术。所有实验牙经1％亚甲蓝染色后剖开牙体和烤瓷冠,观测各组的微渗漏深度。结果超声洁治前采用不同粘结剂粘结的牙体微渗漏深度A组〉c组〉E组（均P〈O．05）。与未进行超声洁治术组比较,使用聚羧酸锌水门汀、玻璃离子水门汀粘结,进行单次超声洁治术的牙体微渗漏深度B组〉A组[（3．36＋1．11）mm比（2．55~0．71）mm,P〈0．05],D组〉c组[（2．96~0．93）mm比（2．02＋0．79）mm,P〈0．05]。而使用树脂粘结剂的牙体进行单次和3次超声洁治术后的牙体微渗漏深度与未进行超声洁治术的牙体比较,即E、F、G3组间差异并无统计学意义（尸〉0．05）。结论超声洁治术对玻璃离子水门汀和聚羧酸锌水门汀粘结的烤瓷冠边缘封闭性产生明显破坏,而对树脂粘结剂粘结的烤瓷冠边缘封闭性无明显影响。     

An investigation of the shear bond strength of compomer restorative material to enamel and dentine

The aim of this study was to investigate the effect of one step adhesives on the shear bond strength of a compomer restorative material to both enamel and dentine. Human extracted teeth were used for the study. Ten samples were prepared for both enamel and dentine specimens for each of the five groups: Tooth, no etch, Prime and Bond NT (P+B NT); tooth, Non-Rinse Conditioner (NRC), P+B NT; tooth, NRC, Prime and Bond 2.1 (P+B 2.1); tooth, etch, P+B NT; tooth, etch, P+B 2.1. The specimens were subjected to bond testing. The shear bond strength was measured using an Inston 1193 testing machine using a cross head speed of 1 mm/minute. The specimens were tested to destruction. The results show that for the enamel specimens the highest bond strength was recorded for those specimens subjected to Etch, P+B 2.1 (22.1 MPa) and Etch P+B NT (20.0 MPa). The groups of specimens which did not undergo etching had very low bond strengths ranging from 11.4 MPa for NRC, P+B 2.1, 8.5 MPa for NRC P+B NT to 6.9 MPa for P+B NT. For the dentine specimens, for all of the groups, the shear bond strengths were low. Those groups subjected to etching produced the highest values of 7.9 MPa for NRC P+B 2.1 with the lowest value of 6.1 MPa for NRC P+B NT. These bond strengths were significantly lower than those achieved for bonding to enamel. Prime and Bond NT and Prime and Bond 2.1, used in conjunction with acid etching, produce satisfactory bond strengths of compomer restorative material to enamel. Bond strengths to dentine were low.     

Microleakage and interfacial morphology of self-etching adhesives in class V resin composite restorations

The purpose of the study was to evaluate the marginal leakage of three adhesive systems in Class V resin composite restorations. Two adhesive systems containing acidic primers: Clearfil SE Bond (CSEB) and Etch & Prime 3.0 (E&P), were compared with a conventional water-based primer: Scotchbond Multipurpose Plus (SBMP). Class V cavities were made at the cementum-enamel junction of extracted human molars, which were then divided between three groups. One of the adhesive systems was applied to each group following manufacturers' instructions. Composite restorations were placed, light cured for 40 s, and polished. Specimens were then immersed in a solution of 2% basic fuchsin dye for 24 h. Longitudinal sections were obtained and studied with a stereomicroscope for assessment of the microleakage according to the degree of dye penetration (scale of 0-3). Data were analyzed by Kruskal-Wallis one-way ANOVA, Mann-Whitney tests, and the Wilcoxon matched-pairs signed rank test. Two specimens for each group were analyzed by scanning-electron microscopy (SEM). Bonded interfaces of dentin were also examined by transmission-electron microscopy (TEM). On enamel, there were no significant differences between the three groups. On dentin, CSEB showed the lowest dye penetration values among the three adhesive systems. SEM and TEM studies showed hybrid layer and resin tag formations in all groups.     

生物活性玻璃抑制酸蚀后不同时间牙釉质的刷牙磨损

背景：生物活性玻璃具有良好的生物相容性,并具有优异的促进牙齿再矿化和抗酸蚀效果。 目的：比较生物活性玻璃牙膏和含氟牙膏对牙釉质酸蚀后不同时间点刷牙磨损的影响。 方法：制备56个牛牙釉质片,树脂包埋并暴露大小约6 mm×6 mm的釉质平面,表面制备沟槽并充填银汞合金,磨平抛光后随机均分为7组,模拟酸性饮食后刷牙的过程,其中6组分别用普通牙膏、含氟牙膏、生物活性玻璃牙膏在雪碧酸蚀后即刻和酸蚀后30 min两个时间点以牙刷磨刷,另1组不酸蚀,只用普通牙膏磨刷,为无酸蚀对照组,过程循环60次。以银汞合金为参照,用激光共聚焦显微镜观察各组样本磨刷后的表面磨损量。 结果与结论：酸蚀后刷牙各组磨损量明显高于无酸蚀对照组(P < 0.05)。在酸蚀后同一时间刷牙条件下,生物活性玻璃牙膏组磨损量均低于含氟牙膏组(P < 0.05);使用同种牙膏条件下,牙齿酸蚀后唾液浸泡30 min后刷牙组的磨损量均低于酸蚀后即刻组(P < 0.05)。说明应用生物活性玻璃牙膏在酸性饮食30 min后刷牙,可有效减少刷牙对酸蚀牙釉质的磨损。  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     

Effect of sodium hypochlorite on dentin bonding with a polyalkenoic acid-containing adhesive system

The purpose of this study was to evaluate the effect of sodium hypochlorite (NaOCl) treatment on dentin bonding by means of contact angle (CA), shear bond strength (SBS), and microleakage (ML) measurements. Ultrastructure and nanoleakage (NL) of the interfaces were examined by transmission electron microscopy (TEM). For CA, SBS, and TEM evaluation, human molars were sectioned to expose dentin surfaces and were either acid-etched (35% H3PO4) or further treated with 5% NaOCl for 2 min before the application of Single Bond adhesive. CAs were measured using the Axisymmetric Drop Shape Analysis technique. The Watanabe testing assembly was used for SBS evaluation. ML was assessed by a dye penetration method. NL was examined using a silver-staining technique. The results showed that CA values decreased after acid etching and even more after NaOCl treatment. NaOCl treatment produced lower SBS than acid-etched dentin. Both ML values and NL manifestations were similar for NaOCl-treated and acid-etched dentin. NaOCl did not completely remove the collagen matrix. NL was manifested along the base of hybrid layers and within the polyalkenoic acid copolymer in both groups. Adverse chemical interactions could have occurred between the remnant collagen matrix and/or mineralized dentin after NaOCl treatment. There is no additional advantage in using NaOCl treatment with this adhesive.     

Enamel microhardness after in vitro demineralization and role of different restorative materials

This study aimed to evaluate the extension of enamel demineralization around the margin of restorations after immersion in cariogenic solution, in an attempt to define the role of new restorative materials in preventing secondary caries formation. For this purpose, enamel microhardness was measured. Twelve class V restorations in human extracted third molars were prepared in vitro and immersed in a demineralizing solution (lactic acid, pH 4.5) at 37°C for 3 days to simulate the formation of secondary caries and its effect on the marginal integrity of composite restorations. The restorative systems tested in the study were Scotchbond 1 + Z 250 (group A), ABF + APX (group B), Fuji IX (group C), SE Bond + APX (group D), and Scotchbond 1 + F 2000 (group E). The microhardness was measured close to the margin of restoration (marginal exposed enamel), at 2.0 mm from the margin (exposed enamel), and at approximately 4 mm from the margin in a varnish-covered enamel area (protected enamel). Five measurements were made on each site at 20, 40, 60, 80, and 100 μm depth from the external enamel surface. Exposed enamel and marginal exposed enamel were greatly affected by the cariogenic solution, as confirmed by the high rate of demineralization. The marginal exposed enamel showed a higher rate of demineralization than the exposed enamel, as demonstrated by the lowest microhardness values. The materials that claimed fluoride release did not prevent any type of enamel marginal alteration. This study revealed that enamel close to the margin of restoration may be rapidly affected by secondary caries formation when immersed in a demineralizing-cariogenic solution and that fluoride-releasing materials are unable to reduce the marginal demineralization processes. These demineralization processes may be responsible for marginal secondary caries and for restoration failures.     

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.     

Osteoconductivity of hydrophilic microstructured titanium implants with phosphate ion chemistry

This study investigated the surface characteristics and bone response of titanium implants produced by hydrothermal treatment using H₃PO₄, and compared them with those of implants produced by commercial surface treatment methods – machining, acid etching, grit blasting, grit blasting/acid etching or spark anodization. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, contact angle measurement and stylus profilometry. The osteoconductivity of experimental implants was evaluated by removal torque testing and histomorphometric analysis after 6 weeks of implantation in rabbit tibiae. Hydrothermal treatment with H₃PO₄ and subsequent heat treatment produced a crystalline phosphate ion-incorporated oxide (titanium oxide phosphate hydrate, Ti₂O(PO₄)₂(H₂O)₂; TiP) surface approximately 5 μm in thickness, which had needle-like surface microstructures and superior wettability compared with the control surfaces. Significant increases in removal torque forces and bone-to-implant contact values were observed for TiP implants compared with those of the control implants (p < 0.001). After thorough cleaning of the implants removed during the removal torque testing, a considerable quantity of attached bone was observed on the surfaces of the TiP implants.     

The effect of six years of water storage on resin composite bonding to human dentin

The aim of this in vitro study was to evaluate dentin bond strength and marginal adaptation of direct resin composite fillings after different storage times. Three hundred sixty cavities were prepared in discs of freshly extracted human third molars and filled with resin composites. Multistep self-etching adhesives (Syntac Classic, A.R.T. Bond, both with and without total etching), three-step etch-and-rinse adhesives (Scotchbond Multi-Purpose Plus, EBS), and two-step etch-and-rinse adhesives (Prime and Bond 2.0, Syntac Single-Component) were used for bonding. After 1, 90, and 2190 days of water storage and 24 h thermocycling (1150 cycles), push-out testing was performed. From the 6-year group, replicas were made after 1 day, 90 days, and 1, 2, 3, 4, 5, and 6 years, and examined regarding marginal adaptation under an SEM (x 200 magnification). In all groups under investigation, push-out bond strengths remained stable after 90 days; however, the strengths significantly decreased after 6 years of water storage. The two-step systems exhibited lower bond strengths than three-step systems after 6 years. Marginal analysis revealed a significant loss regarding the percentage of perfect margins having been stable after 2 years for the three-step etch-and-rinse systems. Overall, the older three-step systems proved to be more effective than the simplified adhesives Syntac Single-Component and Prime and Bond 2.0 with regard to bond strength and marginal adaptation.     

Modulated regeneration of acid-etched human tooth enamel by a functionalized dendrimer that is an analog of amelogenin

In the bioinspired repair process of tooth enamel, it is important to simultaneously mimic the organic-matrix-induced biomineralization and increase the binding strength at the remineralization interface. In this work, a fourth-generation polyamidoamine dendrimer (PAMAM) is modified by dimethyl phosphate to obtain phosphate-terminated dendrimer (PAMAM-PO₃H₂) since it has a similar dimensional scale and peripheral functionalities to that of amelogenin, which plays important role in the natural development process of enamel. Its phosphate group has stronger affinity for calcium ion than carboxyl group and can simultaneously provide strong hydroxyapatite (HA)-binding capability. The MTT assay demonstrates the low cytotoxicity of PAMAM-PO₃H₂. Adsorption tests indicate that PAMAM-PO₃H₂ can be tightly adsorbed on the human tooth enamel. Scanning electron microscopy and X-ray diffraction are used to analyze the remineralization process. After being incubated in artificial saliva for 3 weeks, there is a newly generated HA layer of 11.23 μm thickness on the acid-etched tooth enamel treated by PAMAM-PO₃H₂, while the thickness for the carboxyl-terminated one (PAMAM-COOH) is only 6.02 μm. PAMAM-PO₃H₂ can regulate the remineralization process to form ordered new crystals oriented along the Z-axis and produce an enamel prism-like structure that is similar to that of natural tooth enamel. The animal experiment also demonstrates that PAMAM-PO₃H₂ can induce significant HA regeneration in the oral cavity of rats. Thus PAMAM-PO₃H₂ shows great potential as a biomimetic restorative material for human tooth enamel.     

不同修复材料用于前牙美容修复的远期对照研究

【摘 要】 目的:观察不同修复材料用于前牙美容修复的效果及远期随访结果。 方法:选择80例行前牙美容修复患者进行前瞻性研究,按随机数表法分为A组（40例,58颗患牙）与B组（40例,62颗患牙）。A组采取3M-Z350纳米复合树脂进行修复,B组采用3M-Z100复合树脂进行修复。比较两组术后1 d、术后1周、术后1个月及术后3个月的敏感发生率、疼痛［采用视觉模拟评分法（VAS）评估］及随访3年的边缘密合度、颜色匹配度、修复体完整度。 结果:A组术后1 d、术后1周、术后1个月的患牙敏感发生率分别为8.62%、5.17%、3.45%,显著低于B组的22.58%、17.74%、14.52%（P<0.05）。两组术后3个月的患牙敏感发生率分别为6.91%与16.13%,差异无统计学意义（P>0.05）。A组术后1 d、术后1周、术后1个月的VAS评分分别为2.51±0.54、2.03±0.47、1.58±0.38,均显著低于B组的2.72±0.59、2.35±0.50、1.81±0.42（P<0.05）。两组术后3个月的疼痛VAS评分未见统计学意义（P>0.05）。两组随访3年的修复体完整度差异无统计学意义（P>0.05）。A组随访3年的边缘密合度与颜色匹配度显著优于B组（P<0.05）。 结论:3M-Z350纳米复合树脂用于前牙美容修复的术后敏感发生率低于3M-Z100复合树脂,疼痛更轻,且远期随访的良好边缘密合度与颜色匹配度均更佳,值得推广。     

Effect of load cycling and in vitro degradation on resin-dentin bonds using a self-etching primer

The objective of this study was to evaluate the effect of in vitro degradation and mechanical loading on microtensile bond strength (MTBS) and microleakage (ML) of a resin composite to dentin using a self-etching primer adhesive [Clearfil SE Bond (SEB)] under two hydration statuses. Twenty-four flat dentin surfaces were divided in groups: 1) blot-dried, 2) air-dried. SEB was applied and resin buildups were performed with Tetric Ceram. Specimens were divided in four subgroups: a) sectioned into beams, b) load cycled, c) beams were immersed in NaOCl for 5 h, d) load cycled and immersed in NaOCl. Beams were tested in tension. For ML testing, 80 Class V cavities were prepared and molars divided in subgroups as described above (in group c and d, specimens were kept in distilled water for 1 year, instead of the 5-h NaOCl immersion). ML was assessed by dye penetration. Analysis of variance and multiple comparisons tests were used for MTBS. For ML, Mann-Whitney U and Wilcoxon matched pairs signed ranked were used (p<0.05). SEB applied to completely dehydrated dentin produced the highest MTBS, at 24-h evaluation. In vitro degradation always decreased MTBS, and fatigue loading only diminished MTBS on dehydrated dentin. Load cycling increased dye penetration on dentin margins. Degradation always increased ML in both enamel and dentin margins.     

Visualization of calcium phosphate cement in teeth by zero echo time 1H MRI at high field

¹H magnetic resonance imaging (MRI) by a zero echo time (ZTE) sequence is an excellent method to image teeth. Calcium phosphate cement (CPC) materials are applied in the restoration of tooth lesions, but it has not yet been investigated whether they can be detected by computed tomography (CT) or MRI. The aim of this study was to optimize high‐field ZTE imaging to enable the visualization of a new CPC formulation implanted in teeth and to apply this in the assessment of its decomposition in vivo. CPC was implanted in three human and three goat teeth ex vivo and in three goat teeth in vivo. An ultrashort echo time (UTE) sequence with multiple flip angles and echo times was applied at 11.7 T to measure T₁ and T₂* values of CPC, enamel and dentin. Teeth with CPC were imaged with an optimized ZTE sequence. Goat teeth implanted with CPC in vivo were imaged after 7 weeks ex vivo. T₂* relaxation of implanted CPC, dentin and enamel was better fitted by a model assuming a Gaussian rather than a Lorentzian distribution. For CPC and human enamel and dentin, the average T₂* values were 273 ± 19, 562 ± 221 and 476 ± 147 μs, respectively, the average T₂ values were 1234 ± 27, 963 ± 151 and 577 ± 41 μs, respectively, and the average T₁ values were 1065 ± 45, 972 ± 40 and 903 ± 7 ms, respectively. In ZTE images, CPC had a higher signal‐to‐noise‐ratio than dentin and enamel because of the higher water content. Seven weeks after in vivo implantation, the CPC‐filled lesions showed less homogeneous structures, a lower T₁ value and T₂* separated into two components. MRI by ZTE provides excellent contrast for CPC in teeth and allows its decomposition to be followed.     

Oligomerization of oxiranes in the presence of phosphorus acids, 2. Kinetics of addition of ethylene oxide to phosphoric and phosphorous acid

Kinetics of addition of ethylene oxide to the P? OH groups in phosphorous (H₃PO₃) and phosphoric acid (H₃PO₄) were studied. The reaction is catalysed by the P? OH groups themselves, presumably by formation of hydrogen-bonded complexes with ethylene oxide. The values of apparent rate constants of reactions involving subsequent P? OH groups were determined. The apparent reactivity of P? OH increases with increasing number of ? OCH₂CH₂OH substituents present in the reacting molecule. This has been attributed to the formation of intramolecular hydrogen bonds influencing the reactivity of the P? OH groups. Mechanistic implications and the distribution of products are discussed in connection with the observed kinetic dependences.     

FiltekTM Z 350纳米流动树脂微创修复细小窝沟龋

背景：传统的细小窝沟龋修复需要按Ⅰ类洞形进行预备,对牙体组织破坏较多。 目的：评价流动纳米树脂微创修复细小窝沟龋的临床效果。 方法：选择14~30岁磨牙有窝沟龋且对侧同名牙或邻牙也有窝沟龋患者167例,在一侧磨牙牙合面窝沟龋去除龋坏牙体组织后,采用Adper Single Bond 2全酸蚀黏结技术,用Filtek ^TM Z350流动纳米树脂充填整个微创窝洞作为实验组,对侧同名牙或邻牙窝沟龋用同一公司生产的Filtek ^TM Z350纳米树脂充填作对照。 结果与结论：随访2年后发现实验组Z350流动纳米树脂填充体保留率高,边缘完整性好,边缘着色率低,树脂保留率、边缘完整性及边缘着色率高于对照组(P < 0.05)。提示Filtek ^TM Z350流动纳米树脂微创窝沟充填可有效修复细小窝沟龋。     

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).     

IPS e.max Press全瓷冠用于前牙修复：边缘适合度及颜色匹配随访

背景：IPS e.max Press热压铸全瓷以其较好的美观效果和生物学性能已被越来越多地应用于临床修复。 目的：分析IPS e.max Press全瓷冠用于前牙美学修复的边缘适合度及颜色匹配等情况。 方法：纳入前牙美容修复患者52例(138颗牙),其中男20例,女32例,年龄18-45岁,前牙缺损62颗,牙外伤46颗,畸形小牙30颗,分为2组修复,治疗组(n=26)采用IPS e. max Press全瓷冠和传统钴铬合金烤瓷冠修复,对照组(n=26)采用传统钴铬合金烤瓷冠修复,修复后1周复诊,调查患者满意度;修复后随访6个月、2年,评估修复体完整性、边缘适合度、牙龈健康状况及颜色匹配等情况。 结果与结论：修复后1周,治疗组患者对修复体颜色、外形及舒适度方面的满意度显著高于对照组(P < 0.05);治疗后6个月,治疗组边缘适合度、牙龈健康状况及颜色匹配显著优于对照组(P < 0.05);治疗后2年,治疗组边缘适合度、牙龈健康状况及颜色匹配显著优于对照组(P < 0.05)。表明IPS e.max Press全瓷冠修复前牙具有良好的边缘适合度、牙龈健康状况及颜色匹配等生物学特性,患者满意度高。 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     

Effects of sodium hypochlorite gel and sodium hypochlorite solution on dentin bond strength

The aim of this study was to determine the effect of 10% NaOCl gel and 10% NaOCl solution on dentin bond strengths of four adhesive systems. One hundred eighty bovine incisors were ground to achieve a flat polished surface, then divided into 12 groups: Gluma One Bond [G1-control; G2-NaOCl solution; G3-NaOCl gel]; Prime & Bond 2.1 [G4-control; G5-NaOCl solution; G6-NaOCl gel]; Single Bond [G7-control; G8-NaOCl solution; G9-NaOCl gel]; Prime & Bond NT [G10-control; G11-NaOCl solution; G12-NaOCl gel]. Dentin was etched, rinsed, and blot dried. For the experimental groups, after acid etching, 10% NaOCl solution or 10% NaOCl gel was applied for 60 s, rinsed, and blot dried. Composite resin was inserted and light cured. Shear bond strengths were tested with a crosshead speed of 0.5 mm/min. The mean values MPa (SD) were analyzed with two-way ANOVA and Tukey's tests (alpha < 0.01). Ten percent NaOCl solution significantly increased Gluma One Bond strength. No effect was observed for the other adhesives. The 10% NaOCl gel did not affect bond strengths. Ten percent NaOCl gel was less effective on collagen removal as compared to 10% NaOCl solution. The influence of collagen removal on bond strength is dependent on adhesive system, where both the solvent and the monomer can influence the results.     

Improved photochemical bonding of composites to dentin using 4-methacryloxyethyl trimellitate anhydride

The main objective was to evaluate the use of 4-methacryloxyethyl trimellitate anhydride (4-META) to improve bonding of composite materials to dentin. Bowen's resin, containing camphoroquinone, was polymerized by exposure to visible light. In composites, made with a silanated silicate, inclusion of 4-META (3%) had little effect in increasing mechanical strength or adhesion to bovine teeth. However, direct application of 4-META via acetone solution was found to be an effective way of increasing tensile adhesive strength; by 240% to dentin (to 7.2 MPa) and by 160% to enamel (to 10.8 MPa). Applying the experience mentioned above, 4-META was used to bond a proprietary photocuring microfilled composite material to Class V cavities in freshly extracted human teeth. After thermal cycling between water baths held at 5 degrees C and 60 degrees C, all dentin restorations without 4-META failed, as judged by marginal leakage of a dyestuff. In contrast, using 4-META there was no leakage in 9 out of 10 cases. In restorations involving enamel, 4-META failed to prevent marginal leakage at the enamel margins but did prevent penetration along the dentin/composite interface. It is concluded that 4-META shows great promise for preventing marginal leakage at dentin/composite interfaces.     

酸蚀牙面后黏结树脂嵌体修复牙体的抗力性能

背景：树脂嵌体修复牙体缺损在一定程度上可减少修复后牙齿的折裂,但嵌体经不同方法黏结处理后对牙体抗力的影响未见报道。 目的：了解复合树脂经不同方法处理后修复牙体的抗力特性。 方法：将40颗无龋人前磨牙制作近中-牙合面-远中洞型洞,随机分成4组：其中一组备洞后未进行修复作为对照组,其他3组分别以可乐丽菲露光固化复合树脂直接充填,可乐丽菲露光固化复合树脂嵌体直接黏结和酸蚀黏结修复。 结果与结论：①力学模型静态力学加载实验结果：树脂直接充填组、树脂嵌体直接黏结和酸蚀黏结组断裂载荷均高于对照组(P < 0.05),前3组断裂载荷比较组间差异无显著性意义(P > 0.05),树脂嵌体酸蚀黏结组断裂载荷最大。②扫描电镜观察结果：树脂直接充填组断裂位于牙本质层和树脂之间,几乎无树脂残留,有较多孔隙;树脂嵌体直接黏结组大量牙本质基体与树脂间断裂,有较少树脂残留;树脂嵌体酸蚀黏结组牙与树脂之间无气泡、无缝隙、相互嵌合、紧密接触;对照组,树脂直接充填、直接黏结、酸蚀黏结组分别出现10,5,3,1个样本树脂内聚破坏断裂。表明经酸蚀处理复合树脂嵌体可提高牙体力学性能。