Evaluation of the mechanical properties of dental adhesives and glass-ionomer cements

Adhesives and lining/base materials should relieve the stresses concentrated at the tooth/restoration interface. The study aimed at comparing the mechanical properties of eight adhesives and six glass-ionomer cements (GICs). The adhesives were applied on dentin disks, whereas 2 mm × 3 mm × 2 mm GICs specimens were prepared in a teflon mold. Vicker’s hardness (VH), elastic modulus (E), creep (Cr) and elastic work (We/Wtot) were measured with a micro hardness indenter. One-way ANOVA and Tukey’s test were used to compare the mechanical properties within each materials’ type and among the materials’ classes. Enamel and dentin were used as references. Significant differences were detected within each materials’ type and among the materials’ classes and enamel and dentin. GICs were superior to adhesives in VH and E and showed a VH similar to dentin. GICs presented mechanical properties more similar to enamel and dentin than adhesives.     

Bioactivity of zinc-doped dental adhesives

Design of restorative materials should be focused on promoting not only adhesion but also dentine self-repair processes.     

防龋粘接材料的研究进展

复合树脂和粘接系统广泛应用于修复牙体组织缺损,改善牙体颜色和外观;但目前的树脂及粘接材料普遍缺乏有效的抗菌性能,远期修复效果常受到继发龋的影响。近年来,加入防龋成分的粘接剂有了一定的抗菌性能,具有促进牙体硬组织矿化的作用和良好的生物力学性能,逐渐成为口腔修复材料和龋病防治研究的热点。本文就防龋粘接剂的分类、抗菌粘接剂和促进矿化的粘接剂的研究进展作一综述。     

Disinfection effect of dental impression tray adhesives

Objectives

Iatrogenic infections are serious problems in dental offices. Impression tray adhesives are delivered in glass containers with a fixed brush attached inside the cap. Using the brush for application of the impression tray adhesive on a contaminated impression tray or prostheses, pathogen transmission by replacing the cap with the brush is possible.

Materials and methods

Bacterial strains (patient strains and in vitro strains) were supervaccinated on Columbia agar. The bacterial solution was diluted with TSB and aerobically grown, and starting concentration was 1?×?10⁷ cfu/ml. The stock solution was placed on Columbia agar. Alginate, polyether, and silicon impression tray adhesives were applied to the center of the particular blood agar plates and incubated for 48 h. The expansion of the inhibition zone assays were measured using a microscope.

Results

Twenty-one different bacterial strains were selected in the saliva samples of 20 patients. The growth inhibition for alginate impression tray adhesive was 1.1 % (±0.3) of the patient strains. The overgrowth of polyether impression tray adhesive was 30.6 % (±9.3) and for silicon impression tray adhesive 11.8 % (±5.0). In in vitro strains, alginate impression tray adhesive performed an inhibition of 0.7 % (±0.3). The overgrowth of polyether impression tray adhesive was 7.0 % (±1.6) and for silicon impression tray adhesive was 6.5 % (±1.3).

Conclusions

Using the fixed brush for application of the impression tray adhesive on multiple patients, a cross-contamination cannot be ruled out.

Clinical relevance

An application of the impression tray adhesive with a pipette and a single-use brush would eliminate the contamination.     

Effect of ozone gas application on the mechanical properties of dental adhesives bonded to dentin

OBJECTIVES: To assess the effect of ozone gas on the mechanical properties of different classes of dental adhesives. METHODS: Extracted molars were sectioned perpendicularly to their long axis for obtaining dentin slices to be bonded with one of the following adhesives: Prime&Bond NT (Dentsply), Excite (Ivoclar-Vivadent), Syntac/Heliobond (Ivoclar-Vivadent) and Silorane System Adhesive (3M-ESPE). Prior to bonding, the slices were sectioned in two halves: one was treated with ozone gas for 120s (4.2g/m(3); HealOzone, KaVo) and the other served as control. The Vicker's hardness (VH), elastic modulus (E), elastic work (W(e)/W(tot)) and the creep (Cr) of the materials were measured with an automatic micro hardness indenter (Fischer) 30min and 24h after bonding procedure. Data were analyzed with the multivariate ANOVA followed by the Tukey's test and partial eta-squared statistics. RESULTS: The adhesive and the time of testing were significant factors affecting the investigated parameters (p<0.001; eta(p)(2)>/=0.06). Dentin treatment, though significant, exerted a minimal effect on mechanical properties (eta(p)(2)相似文献   

Fluoride release from newly developed dental adhesives

This study compared fluoride release from three fluoride-releasing dental adhesives (Trial KBF Bond, One-up Bond F, Reactmer Bond) and one conventional dental adhesive (Clearfil SE Bond) for 70 days in vitro. From each material, five disk-shaped specimens (diameter: 9.0 mm, height: 1.5 mm) were prepared and immersed in 5 ml of 10 mM phosphate buffered solution (pH 7.0). After 1, 3, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 days, the samples were transferred into new solutions. The fluoride content was determined with a combined fluoride sensitive electrode attached to an ion analyzer. Data were statistically analyzed with ANOVA, followed by Scheffé's test. Reactmer Bond showed the greatest fluoride release over 70 days (280.2 +/- 10.1 micrograms/cm2) among the materials tested. The values for One-up Bond F and Trial KBF Bond were 83.4 +/- 5.3 micrograms/cm2 and 58.6 +/- 1.5 micrograms/cm2, respectively. The values were significantly different among the four groups (p < 0.0001). Clearfil SE Bond showed almost no fluoride release over 70 days.     

3种黏结剂黏结釉质的界面微渗漏研究

目的：评价3种牙齿黏结剂黏结釉质后界面微渗漏情况。方法：离体尖牙或前磨牙60个，在牙齿的唇颊面磨出直径3mm的釉质平面，用黏结剂（Prime＆Bond NT，Xenol Ⅲ，Adper Prompt）黏结釉质平面，并用复合树脂覆盖。24h后在黏结部位中部，以垂直于黏结界面和牙齿长轴的方向切一细槽，深度超过黏结界面。将每种黏结剂黏结的牙齿分为2组，每组10个，其中一组的牙齿进行10000次冷热循环，另一组浸于37℃水中。在牙齿的表面涂指甲油，然后将牙齿浸于500g／L的氨化硝酸银溶液中，24h后取出，再浸于显影液中，8h后取出。将牙齿纵向并垂直于黏结面切成两半，在测量显微镜下测量剖面银从细槽处沿黏结界面渗入的深度，最后在扫描电子显微镜下观察黏结界面处银渗漏情况。结果：Prime＆Bond NT的未冷热循环组与冷热循环组的银渗漏深度无显著差异（P〉0.05），Xenol Ⅲ及Adper Prompt的冷热循环组的银渗漏深度显著大于未冷热循环组（P〈0．01）。3种黏结剂间相比，Prime＆Bond NT的银渗漏显著小于Xenol Ⅲ及AdperPrompt（P〈.01）。结论：自酸蚀黏结剂黏结釉质的密合性差于酸蚀一冲洗型黏结剂，形成的黏结界面的耐老化性能也不好。     

纤维桩表面经黏结剂涂层后对桩—核树脂黏结性能的影响

目的:比较桩表面2种黏结剂涂层方法对纤维桩—核树脂黏结性能的影响。方法:36根纤维桩随机分为3组,桩表面分别做3种处理。A组不处理,作为对照;B组于桩表面涂双固化黏结剂XP BondTM并光照固化;C组在桩表面涂XP BondTM,使其自固化。处理后的纤维桩与Definit Core树脂黏结制成棒状试件,分别于水存24h和1个月后进行微拉伸强度(microtensile bonding strength,μTBS)测试和扫描电镜观察。采用SPSS 13.0软件包对μTBS的测试结果进行方差分析。结果:水存24h后,C组的μTBS〔(17.03±6.01)MPa〕显著高于A组〔(9.64±4.59)MPa〕和B组〔(11.99±6.07)MPa〕,P<0.05;水存1个月后,3个实验组间的μTBS无显著差异(P>0.05)。B组和C组水存1个月后的μTBS分别为(8.17±4.25)MPa和(9.85±4.11)MPa,均比水存24h后的值显著降低(P<0.05),且在扫描电镜下观察到明显的界面裂缝。结论:黏结剂桩表面涂层对纤维桩—核树脂的即时黏结强度的作用因黏结剂的固化方式而异,2种桩表面涂层方法均会降低纤维桩—核树脂的黏结持久性。     

One-year evaluation of a dentin-enamel bonding system

The 1-year recall evaluation of a dentin-enamel bonding system developed by the author is presented. The system has excellent in vitro resistance to dye penetration and can provide gap-free restorations in vivo. It has shown significant potential for bonding to dentin and enamel.     

Modulating pH through lysine integrated dental adhesives

Objectives

The objective of this study was to explore the effect of lysine integration to dental adhesives with respect to the polymerization kinetics, neutralization capacities in the acidic microenvironment, dynamic mechanical properties, and thermal properties.

Degree of conversion and permeability of dental adhesives

The aim of this study was to analyse the extent of polymerization of different adhesive films in relation to their permeability. One adhesive of each class was investigated: OptiBond FL; One-Step; Clearfil Protect Bond; and Xeno III. Adhesive films were prepared and cured with XL-2500 (3M ESPE) for 20, 40 or 60 s. Polymerization kinetic curves of the adhesives tested were obtained with differential scanning calorimetry (DSC) and data were correlated with microhardness. The permeability of the adhesives under the same experimental conditions was evaluated on human extracted teeth connected to a permeability device and analysed statistically. The results showed that the extent of polymerization obtained from DSC exotherms was directly correlated with microhardness. An increased level of polymerization after prolonged light-curing was confirmed for all adhesives. Simplified adhesives exhibited a lower extent of polymerization and showed incomplete polymerization, even after 60 s. An inverse correlation was found between the degree of cure and the permeability. This study supports the hypothesis that the permeability of simplified adhesives is correlated with incomplete polymerization of resin monomers and the extent of light exposure. These adhesives may be rendered less permeable by using longer curing times than those recommended by the respective manufacturer.     

Effects of MMP inhibitors incorporated within dental adhesives

Matrix metalloproteinase (MMP) inhibition has been shown to reduce adhesive bond degradation when applied as a pre-conditioner, adding to clinical steps in the placement of adhesives, but their incorporation within dental adhesives has not been fully explored. This study examined the effect of including 2 MMP inhibitors (BB94 and GM6001) within the primers of 3 commercially available adhesives. Fluorometric assay and zymography showed that adhesives with MMP inhibitors had high affinity toward both synthetic fluorogenic FRET peptides (95%) and dentin powder substrates, respectively. The immediate microtensile bond strength was enhanced for 2 types of adhesives following the addition of both inhibitors. However, no changes were detected between the control and the inhibitor groups following 3-month storage. The modified two-step etch-and-rinse and single-step systems showed less Rhodamine B penetration to the "hybrid layer" and to the "adhesive", respectively. The incorporation of BB94 and GM6001 within the primers resulted in the inhibition of dentin MMPs with improved initial bond strength and enhanced sealing ability.     

Physical properties and cytotoxicity of antimicrobial dental resin adhesives containing dimethacrylate oligomers of Ciprofloxacin and Metronidazole

Objective

Antimicrobial oligomers synthesized from ciprofloxacin (CF) and metronidazole (MN) were investigated for their potential use in dental adhesives.