In vitro investigation of shear bond strength of a phosphate based dentinal bonding agent

Abstract – The objective with this study was to investigate how the shear bond strength of a phosphate based dentinal bonding agent is influenced by storage in saline at 37°C up to 6 months. The effect of dentin bonding agent on the leachability of calcium fron dentin was also determined. The results showed that the shear bond strength decreased after saline storage. After half a year, the strength was ca. 60%, of the initial dry strength. The bonding agent also accelerated the leaching of calcium from the dentin discs, a finding which was explained as being a result of acidic reactions occurring at the dentin-bonding agent interface. In addition to the increased calcium leachability, the dentin bonding agent peeled off with time from the dentin discs. SEM investigation of the dentin surfaces after either shear strength determination or the film had peeled off due to water storage showed that a residual film was left on the dentin. This film, based on morphologic appearance, is most likely composed of the bonding agent but may also contain residuals of the smear layer.     

Factors affecting in vitro bond strength of bonding agents to human dentin

Four generations of total-etch (fourth, fifth) and self-etching (sixth, seventh) bonding agents for use with resin composites are commercially available in the United States. Innovations in bonding agents include: filled systems, release of fluoride and other agents, unit dose, self-cured catalyst, option of etching with either phosphoric acid or self-etching primer, and pH indicators. Factors that can affect in vitro bond strength to human dentin include substrate (superficial dentin, deep dentin; permanent versus primary teeth; artificial carious dentin), phosphoric acid versus acidic primers, preparation by air abrasion and laser, moisture, contaminants, desensitizing agents, astringents, and self-cured restorative materials. This article reviews studies conducted at the Houston Biomaterials Research Center from 1993 to 2003. Results show that in vitro bond strengths can be reduced by more than 50% when bonding conditions are not ideal.     

Clinical performance of three dentine bonding agents in Class V abrasion lesions without enamel etching

Seventy-six Class V non-undercut abrasion lesions were restored with composite and either Dentine Adhesive,† Bondlite,‡ ; or Dentin Bonding Agent ,§ without enamel etching. Restorations were trimmed and polished after approximately three weeks, and evaluated for integrity and marginal staining. Recall evaluations were carried out at three months, six months and one year. The cumulative loss incidence at one year for Dentine Adhesive, Bondlite , and Dentin Bonding Agent was 83 per cent, 25 per cent, and 33 per cent, respectively. Restorations with Dentin Bonding Agent had the most severe marginal staining, while Bondlite restorations had least marginal staining.     

Push-out strength and SEM evaluation of resin composite bonded to internal cervical dentin

Abstract The bond strength of a resin composite used with a dual-cured dentin bonding system to internal cervical bovine dentin was evaluated using a direct or indirect placement technique. Teeth were sectioned transversely to produce 4 mm-thick specimens. The root canals were enlarged to a standardized taper, treated with a dentin bonding system, and filled with a lightcured resin composite using either direct, incremental composite placement or indirect composite placement of a pre-polymerized composite inlay. The debond stress of indirectly placed restorations using a composite inlay was 8.5 (SD±2.7) MPa which was significantly greater (p<0.0001) than the value of 5.0 (SD±1.9) MPa for composite placed in a conventional, incremental manner. SEM evaluation revealed the indirect placement technique demonstrated increased resin tag density and length as compared to the direct technique. Enhanced retention of resin composite to endodoutically prepared dentin treated with a dentin bonding system was obtained by using a composite inlay technique as opposed to direct, incremental buildup of the material.     

Bonding of composites to dentin using primers

Tensile bond strengths of Scotchbond, Clearfil, Cervident and Coremax dentin primers were measured for bonds formed with or without an applied pressure. All materials showed low bond strength with the non-pressure method and only Scotchbond and Cervident benefited from the application of pressure during bond formation, giving values of approximately 2 MPa, similar to that obtained with glass ionomer cement. In general, pretreatment of the dentin with demineralizing agents gave reduced or unchanged bond strengths, as did various aqueous metal salt solutions advocated in the literature. The bond strengths obtained with the primers were insensitive to the quantity applied. All primers bonded better to enamel and synthetic hydroxyapatite than to dentin.     

Bond strength of composites applied to acid-etched enamel

ABSTRACT – The adhesion to acid-etched enamel of a four-component composite, Concise® Enamel Bond System, was studied. The composite was applied undiluted over an intermediate resin layer and diluted with different amounts of resin. Corresponding surfaces of contralateral premolars were used to ensure that the composite samples were tested on areas with similar enamel etch patterns. Eighty specimens were tested. The results of this study indicated that the adherence of undiluted composite to etched enamel surfaces was not improved by using an intermediate layer of low-viscous resin. Composite diluted with liquid resin had poorer adherence than undiluted composite. There was no difference in the results from two degrees of dilution.     

Dentin bonding agents: correlation of early bond strength with margin gaps

Tensile and shear bond strengths between restorative resin and flat human dentin surfaces were determined 15 min after polymerization of various resin systems in combination with 5 dentin bonding agents. The maximum marginal contraction gaps around cylindrical dentin cavities were measured for the same material combinations. A correlation was established for the linear relationship between the logarithm of the contraction gaps and the shear bond strength (r=−0.88). However, the rather wide 95% interval of prediction indicates that strength values do not adequately delineate the effectiveness of dentin bonding agents when used in cylindrical cavities. Early determination of bond strengths and gap widths is considered suitable to estimate the clinical efficacy of dentin bonding agents.     

A laboratory study of the effect of thermocycling in saline and artificial saliva on two dentine bonding agents

Thermocycling of composite resins in saline and artificial saliva was carried out in order to determine the effect of these solutions on the bonding of Lumifor/Gluma and Valux/Scotchbond to dentine and enamel. Minimal Class V cavities were prepared in extracted human teeth and restored with light-cured composite resins, following each manufacturer's instructions. The restored teeth were subjected to 500 cycles at temperatures ranging between 5 degrees C and 45 degrees C. One group was thermocycled in saline, the other in artificial saliva. The resultant marginal gaps were stained and evaluated microscopically. No difference was found between the respective composite resins. However, significantly more gaps were present in those restorations thermocycled in saline.     

Bond strength of five current adhesives to caries-affected dentin

Five current dentin adhesives were evaluated for their ability to bond to caries-affected dentin. The materials were: total etch [Solid Bond (SB)], two self-etch [Clearfil SE Bond (CSE), Etch and Prime (EP)], two one bottle [Prime and Bond 2.1 (PB), One Coat Bond (OCB)]. Sixty extracted molar teeth with proximal caries (mesial or distal) extending into mid-dentin were used. By grinding normal and caries-affected proximal surfaces, flat dentin surfaces were obtained. The surfaces were then bonded with each adhesive system and composite resins were added to the surfaces by packing the material into a cylindrical-shaped plastic matrix with an internal diameter of 2.5 mm and height of 3 mm. Shear bond testing was performed following 10 days incubation of specimens in distilled water at 37 degrees C. Results were analysed by Kruskal-Wallis ANOVA, and Mann-Whitney U multiple comparison test and Wilcoxon rank tests. The results obtained with CSE, SB, and EP were similar in caries affected and normal dentin (P > 0.05). But bonds made to normal dentin with OCB and PB were lower (P < 0.05) than bonds to caries-affected dentin. Bonding to caries-affected dentin with CSE (24.49 +/- 5.38), SB (21.49 +/- 9.15), and EP (21.19 +/- 9.17) showed shear bond strengths higher than OCB (17.43 +/- 9.78) and PB (14.10 +/- 7.94) (P < 0.05). Bonding to normal dentin with CSE (29.91 +/- 8.95) was the highest (P < 0.05). SB (21.17 +/- 5.41) and EP (17.45 +/- 6.21) showed shear bond strengths higher than OCB (11.99 +/- 10.15) and PB (10.57 +/- 4.56) (P < 0.05).     

Carisolv去龋对牙本质黏结强度影响的实验研究

目的：研究Carisolv去龋对牙本质黏结强度的影响：方法：选择30颗新鲜拔除的[牙合]面中度龋损的第三磨牙，每个牙的龋洞分成两半，一半用Carisolv去龋，另一半用慢速球钻去龋，而后随机分成3组，分别使用Prime＆Bond NT＋Dyract AP复合体黏结；Uni—Etch（320ml／L磷酸）＋One—Step Plus＋Renew树脂黏结：Prompt—L—Pop＋Z100树脂黏结。测试微抗拉强度（MTBS）：结果：Cafisolv组3种黏结系统MTBS分别为：（17．22±7．95）MPa、（25．40±8．44）MPa、（17．66±8．33）MPa，车针组分别为：（16．01±7．43）MPa、（23.45±7．55）MPa、（16.26±7.97）MPa：2种去龋方法间差异无显著性。结论：Carisolv去龋法对以上3种黏结系统与牙本质的黏结强度无不利影响：     

三种牙本质黏结剂对人牙髓细胞的细胞毒性

目的：比较不同固化时间下3种牙本质黏结剂（Dentin bonding agents，DBA）对牙髓细胞的细胞毒性，指导临床上合理选择黏结剂和掌握固化时间。方法：组织块培养法进行人牙髓细胞原代培养，并以免疫组织化学染色法鉴定。采用MTT比色分析法来评价3种DBA（Prime＆BondNT，Pb；XenoⅢ，Xe；AdheSE，Ad）的细胞毒性。结果：经ANOVA和Dunnett—t检验，与对照组相比，固化10s和40s的3种牙本质黏结剂对牙髓细胞均有毒性（P〈0．001），与浸渍液作用24h后一些牙髓细胞变圆、皱缩、失去细胞突起。固化10s的3种DBA中Ad对细胞毒性最大，Pb毒性最小；固化40s的3种DBA中Xe毒性最大，Pb毒性最小。与固化10相比，Xe和Ad固化40s可以减轻对牙髓细胞的毒性，经student—t检验，P〈0．01。结论：3种牙本质黏结剂对体外培养牙髓细胞均有一定毒性，延长固化时间可以减轻对牙髓细胞的毒性。     

Biocompatibility of dentin bonding agents

Abstract Dentin bonding agents were introduced to enhance the bonding of composite resins to dentin. Many commercial brands of bonding agents are now available for clinical use, and they are getting more and more popular. The third generation of dentin bonding agents seems to be more effective than earlier generations, although more complex to use. Dentin bonding agents have different chemical compositions, different mechanisms of actions, and different clinical application procedures and, conceivably, different biological effects on the pupal tissues are expected. The reported biological effects of dentin bonding agents ranged from none to severe, depending on several factors. Opinsion varied whether the inflammatory reactions associated with some bonding agents were due to the tooth restoration interface, or due to a combination of both factors.     

改良第八代粘接剂对龋影响牙本质粘接性能的影响

目的:第八代粘接剂Single Bond Universal(SBU)是最新一代的粘接剂,表没食子儿茶素没食子酸酯(Epigallocatechin gallate,EGCG)是基质金属蛋白酶抑制剂及偶联剂,本研究探讨添加EGCG是否可以提高SBU粘接强度及降低微渗漏.方法:将人中龋离体牙去除冠部釉质,龋指示剂下制备龋...     

Carisolv去龋对牙本质粘结界面影响的实验研究

目的:研究Carisolv去龋对牙本质粘结界面的影响。方法:24颗新鲜拔除的中度龋损的第三磨牙,随机分成ABCD4组。每个牙的龋洞分成两半,一半用Carisolv去龋,另一半用涡轮车针去龋后,做如下处理:A组不处理;B组320ml/L磷酸酸蚀,扫描电镜观察牙本质表面形态;C组不酸蚀,DyractAP复合体充填;D组320ml/L磷酸酸蚀后复合树脂充填,扫描电镜观察牙本质-充填体界面。结果:A组:Carisolv去龋后牙本质表面玷污层少,大部分牙本质小管口开放,清晰可见,表面粗糙不平;涡轮车针去龋后牙本质表面覆盖较厚玷污层,牙本质小管口堵塞,很少见到开口。B组:Carisolv去龋组和涡轮车针去龋组均去除了玷污层,牙本质小管口开放,但Carisolv组牙本质小管无管塞,而涡轮车针组牙本质小管残留部分管塞。C组:观察牙本质-复合体界面见Carisolv去龋组有较多树脂突形成,深入牙本质小管及管周;而涡轮车针去龋组未见明显树脂突起形成。D组:观察牙本质-树脂界面见2组树脂突的密度和长度无明显差异,但Carisolv去龋组树脂突之间的侧枝连接较涡轮车针去龋组多见。结论:Carisolv去龋后牙本质表面玷污层少,牙本质小管口开放,表面粗糙不规则,利于粘结,尤其在使用不需酸蚀的复合体充填时优势突出。     

2种树脂黏固剂产品与人牙本质黏结性能的研究

目的探讨2种树脂黏固剂对进行和不进行处理的人牙本质是否具有相同的黏结效果。方法将30枚人牙本质试件分为6组,分别施以不同表面的处理（A、B组不处理 C、D组磷酸酸蚀15s E、F组磷酸酸蚀15s后使用One-step通用型黏结剂）。A、C、E组使用RelyX Unicem双固化树脂黏固剂,B、D、F组使用Bis-cem双固化树脂黏固剂,制作牙本质/树脂黏固剂黏结试件,测试剪切黏结强度,扫描电镜观察黏结界面形态。结果统计分析可知组A和组B的黏结强度值分别低于组C、E和组D、F,组C与组E间以及组D与组F间无统计学差别。RelyX Unicem树脂黏固剂除对于磷酸酸蚀牙本质的黏结强度高于Biscem树脂黏固剂外,牙本质进行其他表面处理或不处理时,2种树脂黏固剂间的黏结强度无明显差别。结论磷酸酸蚀能够提高RelyX Unicem和Biscem2种自黏结树脂黏固剂对牙本质的黏结强度。     

龋影响牙本质粘接强度的研究进展

对于大多数粘接剂而言,龋影响牙本质的粘接强度均低于正常牙本质的粘接强度。本文回顾近几年有关龋影响牙本质粘接强度的文献,着重介绍不同去龋方法、表面处理和粘接剂对龋影响牙本质粘接强度的影响。     

Bond strength of newer dentin bonding agents in different clinical situations

This study compared the tensile bond strengths of different adhesive systems to different dentinal substrate conditions. The adhesive systems used were Adper Single Bond 2 total etch, XP Bond total etch, and two all-in-one adhesives, Adper Easy One and Xeno V. Ninety-six intact human premolars extracted on periodontal or orthodontic grounds were collected and stored in 0.9% physiologic saline for less than four weeks. Teeth were carefully cleaned to remove the soft tissue remnants. The occlusal surfaces were ground until the level of the dentinoenamel junction, exposing superficial dentin using a low-speed diamond disc. A standard smear layer was produced by wet sanding the dentin surface with 600-grit silicon carbide sandpaper for 40 seconds. The 96 specimens were embedded in autopolymerizing acrylic resin and divided into four groups of 24 each based on the dentin bonding agents used. Each group consisted of 24 specimens, which were further divided into two subgroups of 12 specimens each, moist dentin and dentin air-dried for 10 seconds. The regions of interest for adhesion were demarcated in each sample using adhesive tape, with a 4-mm–diameter hole isolating the peripheral region, and each adhesive system was employed. Four adhesive systems, two total etch and two self-etching adhesive, were applied to different dentinal substrates as per the manufacturers' instructions. Following the adhesive application, the specimens were restored with composite material using a metallic mold measuring 5 mm in diameter and 5 mm in height to keep the material in cylindrical form and were light cured per manufacturers' instructions. After being stored for 24 hours in distilled water at room temperature, the specimens were thermocycled for 550 cycles at temperatures ranging from 5°C to 60°C with a dwell time of 15 seconds in each bath and a transfer time of five seconds. The tensile bond strengths were determined using a Universal loading machine (Lloyd Universal Testing Machine) at a cross-head speed of 1 mm/min. On moist dentin, total-etch adhesives showed higher bond strength than did the all-in-one adhesives. Under the dry dentin condition, XP Bond exhibited significantly higher bond strength than did the Adper Single Bond 2 and two all-in-one adhesives, Adper Easy One and Xeno V.     

Effect of combining dentin bonding agents

Abstract The wall-to-wall polymerization contraction of a light-cured composite was measured in cylindrical dentin cavities treated with the bonding agents: Scotchbond, Clearfil Bond, Gluma/Scotchbond, Gluma/Silux Enamel Bond or Gluma/Clearfil Bond. Marginal gaps were prevented in 29 out of 30 cases when Gluma was used in combination with Clearfil Bond. This combination mediates a mean bond strength between composite and dentin of 20 MPa.     

Lipidhistochemical and microradiographic study of distribution of lipids in relation to mineral content in dentin caries

abstract – Fifteen human molars were investigated using lipidhistochemical and microradiographic methods. A peripheral neurotic and totally decalcified part of the carious lesion revealed a markedly positive staining reaction for sphingomyelin, sulfatides, cholesterol- and/or triglyceride-esters. The reaction was probably conditioned by the presence of debris and plaque within this area. Pulpally and immediately below the necrotic zone, an area of demineralization was found which on the microradiographs appeared as a radiolucent zone. The zone showed a mineral gradient with an increasing mineral content towards the pulp. In the zone of demineralization a positive reaction occurred for sphingomyelin decreasing in a pulpal direction with increasing mineral content. A weakly positive reaction for cholesterol- and/or triglyceride-esters, was also delected bat only in the most pulpal part of the zone of demineralization; the intensity of the staining reaction was comparable to that found in normal dentin, In chose areas which were represented by a sclerotized, radiopaque zone, only a very weak reaction for sphingomyelin, cholesterol- and/or triglyceride-esters could be observed of the same staining intensity as in normal dentin. The region between the lesion and the pulp showed the same staining intensity as normal dentin.     

Scanning electron microscopy of attrited dentinal surfaces and subjacent dentin in human teeth

abstract – Attrited dentinal surfaces and subjacent dentin were examined in the scanning electron microscope. In a central area of the exposed surfaces the dentinal tubules were occluded, whereas peripherally most tubules were open. Deposits, apparently dental plaque, were observed on the exposed dentin as uneven, but often continuous, layers covering whole areas of the surfaces. Loss of dentin within delimited areas of the surfaces was observed. The resulting defects could hardly be related to attrition, and it seemed that they were caused by erosive or caries-like processes. The dentin subjacent to the attrited surfaces was characterized by mineralized inclusions in the dentinal tubules. The inclusions consisted of irregularly rod-shaped crystals forming a meshwork on the tubule walls. Other crystals were formed as prisms, seemingly rhombohedrons. Crystals which were hexagonal in cross-section were also seen. The exposure of the dentin also seemed to have influence on the organic content of the tubules. Thus, it appeared that ground substance was removed from the intratubular fibers permitting the observation of cross-banding typical of collagen at their surfaces. In some tubules the fibers seemed to be covered by mineral.