Effect of the Tenure Dentin Bonding System on Leakage of Light-Activated Liners

This study investigated the effect of the Tenure dentin bonding system on the sealing properties of four light-activated liners. Dentinal slot preparations were made in extracted human molars and "restored" with Cavalite, TimeLine, VLC Dycal, and Zionomer liners. Samples were immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned, and examined with an optical microscope. Our results indicated that the Tenure dentin bonding system reduced dye penetration around each of the light-activated liners tested. The Tenure/VLC Dycal system provided a more effective seal than the other liners.     

Histo-pathological study of pulp response to a composite resin restoration with two lining materials

This histopathological study investigated the pulp reaction to a restoration system employing a posterior composite resin with or without the pulp protection of visible light curing calcium hydroxide composition and alpha-TCP cement lining to dentin. Black's class V cavities were prepared in 120 adult dog teeth. They were then extracted for histological examination. As a result of this study, their lining materials were found to be effective in pulp protection. To understand the pathological finding, the pH values of "Fulfil", "Universal bond", "VLC Dycal" and "Vitacemen Type II" were measured. The pH levels of "Fulfil" and "Universal Bond" were mildly acidic (4.79-5.18) before polymerization, with no subsequent changes. "VLC Dycal" was initially a strongly alkaline (11.75) and remained this condition. "Vitacemen Type II" was initially acidic (3.78), but eventually reached the milder acidity of 5.12 after 24 hours.     

iBond粘结剂、Single Bond粘结剂用于比格犬直接盖髓术的组织学评价

[摘要] 目的 对第七代牙本质粘接剂iBond和第五代牙本质粘接剂Single Bond及VLC Dycal的体内细胞毒性进行研究。方法 选择4只比格犬共72颗健康牙齿,在颊面制备Ⅴ类洞并在洞底做人工穿髓孔,然后分为3组,第1组和第2组分别用Single Bond和iBond,第3组用VLC Dycal盖髓作为阳性对照组。选取比格犬口内剩余健康牙齿24颗,不做处理作为阴性对照组。所有实验牙齿分别在盖髓后的第7、30天拔出,并进行组织学评价。结果 7 d时,3组材料均出现不同程度的炎症反应和组织紊乱,但其差异无统计学意义;30 d时,iBond和VLC Dycal两组的炎症反应较Single Bond组弱,其差异有统计学意义(P<0.05);3组材料均有不同程度的组织紊乱,其差异无统计学意义;所有样本未见有牙本质桥形成。结论 iBond对牙髓的刺激性较小;Single Bond对牙髓的刺激性较大。     

Leakage of chemical and light-cured basing materials

This study investigated the sealing properties of chemical and light-cured basing materials in dentin. Fifty extracted molars were selected and cleaned. Slot preparations with standard dimensions were made. The prepared cavities were filled with Cavitec, Life, Ketac-Bond, VLC Dycal, and Cavalite materials. Samples were immersed in 0.05% crystal violet solution for 2 hours. The samples were then embedded in clear casting resin, sectioned, and examined with a microscope. Results indicated that Cavalite and Ketac-Bond materials allow a greater degree of dye penetration that the three other materials. Cavitec, VLC Dycal, and Life materials were similar to each other in degree of dye penetration.     

In vitro cytotoxicity of one-step dentin bonding systems

The cytotoxicity of resinous monomers may vary on mixing, calling into question the cytotoxicity of the new dentin bonding agents that are mixed in a single vial. The cytotoxicity of fourth and fifth generation dentin bonding agents was compared in vitro. All-Bond 2, One-Step, Scotchbond Multi-Purpose, Scotchbond One, Syntac, Syntac Single Component, Tenure, and Tenure Quick were tested uncured. The cytotoxicity of several dilutions of fourth generation dentin primer, dentin bonding agent, dentin primer + dentin bonding agent, and fifth generation single component products diluted at 10(-1) to 10(-8) in culture medium was recorded with a MTT assay on L929 fibroblasts. Only one synergistic (increased cytotoxicity after mixing primer and bonding agent) cytotoxic effect was observed with Tenure at 10(-5) dilution. An antagonistic effect (decreased cytotoxicity after mixing primer and bonding agent) was observed with All-Bond 2 between 10(-4) and 10(-8) dilutions. Scotchbond and Syntac fifth generation dentin bonding agents were less cytotoxic than their fourth generation counterparts. All-Bond and Tenure fifth generation dentin bonding agents were more cytotoxic than their fourth generation counterparts only in low dilutions. Clinical studies should confirm these good results, because no dramatic synergistic cytotoxic effect could be detected.     

Comparison of sealing efficacy of materials placed in lateral root perforations--an in vitro study

An endodontic perforation interferes with the principal goal of sealing the root canal system. An in vitro study was conducted on comparative efficacy of three materials-Dispersalloy, Cavit and Prisma VLC Dycal when placed in lateral root perforations in cervical third areas. Root canals were prepared and irrigated thoroughly. Perforations were made with No. 2 round bur and sealed with Dispersalloy, Cavit and Prisma VLC Dycal. Dispersalloy Group I showed best sealing ability. Prisma VLC Dycal Group I too was comparable to Dispersalloy Group I in its sealing ability, followed by Cavit Group II, Prisma VLC Dycal Group II, Dispersalloy Group II in that order. Cavit Group I was least effective in sealing perforations.     

In vitro evaluation of pH changes induced by calcium hydroxide liners.

OBJECTIVES: Since the highly alkaline pH of calcium hydroxide is considered by many to be responsible for its biologic activity, the possible variations of pH induced by the different calcium hydroxide liners are accepted as a major concern. The aim of the present study was to determine the pH changes of five different calcium hydroxide liners and variations of pH levels at different time intervals. METHOD AND MATERIALS: The materials tested were Dycal, Life, Calic, Dycal VLC, and Calcident 450. Samples were prepared according to manufacturer instructions and by using plastic molds; five standard samples from each material were prepared. The samples were then placed in separate vials, containing 10 mL deionized water (pH 7.0), and stored at room temperature (200C). The pH measurements were taken 1 hour, 24 hours, 3 days, and 7 days after mixing. The pH variations of each material at the given time intervals were recorded, and the means were calculated. RESULTS: Statistical analysis showed significantly high differences between the mean pH values induced by each material at all time intervals. The highest value for the first-hour measurement was for Dycal VLC, and the highest values for the other time intervals were for Calcident 450. The pH values of the materials exhibited statistically significant differences among all the time intervals. CONCLUSION: All materials changed the pH of deionized water toward alkaline.     

Microleakage of composite resin cores treated with various dentin bonding systems

Composite resin post and cores have gained widespread acceptance as an alternative for cast-gold post and core systems. A prefabricated metal post is generally used. Substantial microleakage at the interface between the composite resin core and the dentin substrate may occur. A tight and impervious bond between the dentin and the restorative material is critical for the longevity of core restorations. This study compared the microleakage of composite resin cores treated with various dentin bonding agents, including the recently developed Gluma, Tenure, and Scotchbond 2. The results indicated that Tenure and Scotchbond 2 bonding agents were most effective in reducing microleakage, followed by Gluma and conventional Scotchbond (Dual Cure) bonding agents. Although all proprietary dentin bonding systems used in this study significantly reduced microleakage, no system was capable of preventing microleakage completely.     

Tensile bond strength of dental adhesives to dentin and enamel

This study compared the tensile bond strengths of an unfilled resin bonding agent and four proprietary dentin bonding agents to dentin and acid-etched enamel. Forty-eight hours after bonding, 10 dentin-bonded teeth and 10 enamel-bonded teeth for each material were loaded in tension in an Instron Universal Testing Machine until bond failure. The remaining specimens were stored in a water bath for six months and then tested in a similar manner. At the end of six months, Universal Bond and Tenure (3-step) had bond strengths significantly greater than those of the other agents. All bonding agents, except Tenure (3-step), showed a significant decrease in tensile bond strength to both dentin and enamel after six months (p less than 0.0001).     

牙本质黏结剂对牙髓直接影响的动物实验

目的：观察两种牙本质黏结剂对活体牙髓组织的影响，并与氢氧化钙直接盖髓结果进行对比。方法：选用54个犬牙，机械穿髓后，无菌蒸馏水冲洗，控制穿髓孔处的出血和渗出。使用优邦(UB)和Adper Prompt Self-etching Adhesive(AP)两种牙本质黏结剂盖髓，Dycal作对照。于7、30、90d拔除实验牙，脱钙切片，HE染色、Mallory三色法染色和Gram快速细菌染色检查?结果：所有处理组在短期都出现了轻到中度的炎症反应，在长期的观察中，UB和AP两组出现持续的慢性炎症反应，均未发现牙本质桥肜成。Dycal组出现更多的修复性牙本质，并有牙本质桥形成(P＜0．05)结论：这两种牙本质黏结剂会引起牙髓的慢性炎症反应，在穿髓孔不能形成完整的牙本质桥，临床上这两种黏结剂不能直接与牙髓接触。     

Microleakage between composite resin and basing materials.

This study investigated the microleakage between a composite resin restorative material and six basing materials. Cavities were prepared in polymerized composite resin samples and "restored" with Cavitec, Life, Ketac-Bond, BaseLine, Cavalite, and VLC Dycal. The samples were thermocycled and immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned and examined with an optical microscope. Our results indicated that Cavalite and VLC Dycal allowed no dye penetration. Cavitec and Life had a moderate degree of dye penetration and Ketac-Bond and BaseLine had a relatively high degree of penetration.     

Microleakage between Composite Resin and Basing Materials

This study investigated the microleakage between a composite resin restorative material and six basing materials. Cavities were prepared in polymerized composite resin samples and "restored" with Cavitec, Life, Ketac-Bond, BaseLine, Cavalite, and VLC Dycal. The samples were thermocycled and immersed in 0.05 percent crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned and examined with an optical microscope. Our results indicated that Cavalite and VLC Dycal allowed no dye penetration. Cavitec and Life had a moderate degree of dye penetration and Ketac-Bond and BaseLine had a relatively high degree of penetration.     

Physical properties of calcium hydroxide and glass-ionomer base and lining materials

Compressive, diametral tensile and flexural strengths, moduli of elasticity, pH, and acid solubility values were compared for six calcium hydroxide cements, seven glass-ionomer cements, and one calcium aluminate cement. Results indicated that the glass-ionomer materials were generally stronger than the calcium hydroxide liners. Prisma VLC Dycal showed the lowest value for modulus of elasticity and the least acid solubility. The glass-ionomer materials were initially acidic, reaching a final pH between 5.4 and 7.3, whereas the calcium hydroxide and calcium aluminate cements were strongly alkaline at all time intervals.     

Observations on cavity liners for composite resin restorations

Adhesion or surface roughness and discoloration at the interface between pulp-insulating materials and composite resins were taken as indications for interaction between the resins and the insulating materials. Some interaction occurred between all insulating materials and resins investigated. After separation of the restorative resins, the interaction of Dycal with the different composite resins varied considerably and decreased in the following sequence: Opotow, Natural, and Adaptic. The interactions of ZOE with Natural and with Adaptic were similar and more pronounced than the interaction at the Adaptic-Dycal interface but less pronounced than at the Dycal-Natural interface. A very thin film of Tubulitec was found to adhere to the composite resins in some areas.The adherence of liners containing calcium hydroxide to dentin was found to be generally stronger than the bond between these liners and composite resins. Separation of the composite resins caused tears in the varnishes and frequently in Hydroxyline. Almost completely intact layers of the varnish Copalite were observed on dentin, but Zahnlack apparently dissolved to a great extent in the resins.Among the liners containing calcium hydroxide, Dycal and Tubulitec were found to give rise to a high pH in samples of saliva, but Hydroxyline did not. Porosity and a folded surface were observed for Hydroxyline, indicating the entrapment of the solvent beneath a dry superficial layer.     

Antimicrobial activity of calcium hydroxide liners on Streptococcus sanguis and S. mutans

The antimicrobial activity of 10 calcium hydroxide liners on Streptococcus sanguis and S. mutans was studied. One hundred plates of tryticose soy agar-sheep red blood cells (10%), each with four distinct 3 mm diameter wells, were divided into two groups of 50. One group was inoculated with S. sanguis and the second group with S. mutans. A 4 mg liner was placed in each of three wells; the fourth well was left empty as a control. Plates were incubated at 37 degrees C and observed at 24 hours, 48 hours, and 7 days. All liners inhibited growth of both organisms. The inhibitory zones for S. mutans were larger than inhibitory zones for S. sanguis for all tested liners. Life Fast Set material had significantly less inhibitory effect on S. mutans. VLC Dycal, Life, and Life Fast Set materials had significantly less inhibitory effect on S. sanguis at p = 0.05.     

Pulp tissue reactions to a dentin bonding agent as a direct capping agent

The aim of this study was to investigate the response of human pulp tissue to a dentin bonding agent, Scotchbond Multi-Purpose Plus (SMPP), in exposed class V cavities. Sixteen human premolar teeth were mechanically exposed. Ten pulps were capped with SMPP and six teeth were capped with Dycal. The cavities were filled with a composite. After 40 days, the teeth were extracted and processed for histologic evaluation. Of the 10 teeth capped with SMPP, eight showed moderate chronic inflammation, one was severely inflamed, and one pulp had no to slight inflammation. None of the teeth capped with SMPP showed dentin bridge formation. Of the six teeth capped with Dycal, three exhibited incomplete dentin bridges associated with no to slight inflammation, and three showed no to slight inflammation, without formation of dentin bridges. Direct capping with Dycal with subsequent sealing with SMPP may show favorable results in pulp tissue. SMPP may cause inflammatory changes when applied directly to exposed pulp tissue.     

Microleakage between different types of base materials.

This study investigated the sealing properties of various combinations of base materials. Three chemically cured and three light-activated base materials were combinationally used to make 15 sample groups. The samples were thermocycled and immersed in 0.05% crystal violet solution for 1 hour. They were then embedded in clear casting resin, sectioned, and photographed. The interfaces of the samples were digitized. The ratio of the total interface length to the penetration of leakage was calculated and compared. The results indicated that the combination of Cavalite and VLC Dycal materials had the least microleakage and was significantly different from the other 14 groups.     

Shear bond strengths of the tenure dentin bonding systems

A third generation dentinal bonding system, Tenure Solution dentin bonding system, has recently become commercially available. The original system has been modified twice. The objectives of this in vitro study were to determine the shear bond strengths of the three systems to dentin 15 minutes after specimen preparation, after 24 hours storage in physiological saline at 37 degrees C with and without temperature cycling, and after 4 weeks storage with and without temperature cycling. The shear bond strengths decreased with duration of storage but of each storage interval temperature cycling had no adverse effect on shear bond strength.     

Adhesion characteristics of visible light-cured denture base material bonded to resilient lining materials

This investigation compared the adhesion of resilient lining materials to Triad visible light-cured denture base material. The liners used were Tru-Soft, Molloplast-B, and Esscheem. Cylindrical samples were made from Triad VLC material and were sectioned to produce a flat bonding surface, which was roughened and treated with Triad bonding agent. Resilient liners 3 mm thick were processed according to the manufacturer's recommendations and samples were stored at 37 degrees +/- 1 degree C in distilled water for 48 hours and 30 days. Tensile bond strength was determined by using an Instron Universal testing machine for the three resilient liners.     

Adhesion to Dentin

The bond strengths of dentinal bonding systems to dentin and the microleakage at the dentinal bonding system to dentin interface are often determined in laboratory studies prior to the clinical evaluation of these systems. The shear bond strengths of some of the third generation dentinal bonding systems to dentin and the microleakage at the dentinal bonding system to dentin interface are discussed. In addition, the shear bond strengths of fluoride-containing liners/bases and the fluoride release from these systems are evaluated.