Dentin Adhesives Research Articles

Evaluate the effect of different mmps inhibitors on adhesive physical properties of dental adhesives, bond strength and mmp substarte activity

We have evaluated and compare the effect of different exogenous MMP inhibitors on adhesive physical properties of dental adhesives, bond strength, micro permeability and MMP substrate activity. 180-grit Sic paper was used to obtain the superficial dentin surface from each and every tooth after the wet grinding procedure. Dentin was exposed to four different MMP inhibitors to evaluate the effect on resin adhesive dentin interface. The four groups used in study were: 2% chlorhexidine digluconate, 2% doxycycline solution, 5% Proanthocyanidin (PR), Control Group. We evaluated and compared the four groups at each and every step of etching, bonding and resin application. Then, the immunolabeling was done with the help of the secondary antibodies with the pH of 7 and the dilution of 1:20. Amongst all the etching pretreatment groups, CHE group (Chlorhexidine etching group) revealed highest exposure to collagen fibrils than the other groups of etching. Then after the CHE group, the next group which has the second highest exposure DOE group. MMP inhibitor application for time duration of 1 minute after the etching procedures significantly improves the bond strength, exposure to collagen fibres and uniforms the dense form of dentin hybrid layer.

Clinical Performance of Different Solvent-based Dentin Adhesives With Nanofill or Nanohybrid Composites in Class III Restorations: Five Year Results.

To evaluate the clinical performance of water, acetone, ethanol, and ethanol-water solvent-based dentin adhesives with nanofill or nanohybrid composites in Class III restorations. A total of 22 patients aged between 14 and 48 years (mean age: 25.2 years) participated in the study. Each patient received four Class III restorations, which were performed using water (Scotchbond Multipurpose), acetone (Prime&Bond NT), ethanol (XP Bond) and ethanol-water (Xeno V) solvent-based dentin adhesive systems with a nanofill (Filtek Supreme XT) or nanohybrid composite (CeramX Duo). Two experienced examiners evaluated the restorations with regard to retention, color match, marginal discoloration, wear/loss of anatomic form, caries formation, marginal adaptation, and surface texture at baseline and at one-, two-, three-, four-, and five-year recalls. The five-year survival rates were 100% for Scotchbond Multipurpose, Prime&Bond NT, and XP Bond and 81.2% for Xeno V-bonded restorations. Only three Xeno V-bonded restorations failed. With the exception of marginal discoloration, there were no statistically significant differences among the four adhesive-bonded restorations in any of the evaluation periods in terms of the evaluation criteria. With the exception of marginal discoloration and marginal integrity deterioration of Xeno V-bonded restorations, all four adhesive-bonded restorations exhibited good long-term results. However, adhesion strategy (such as self-etch or etch-and-rinse) is more important than the solvent content of dentin adhesive systems in the success of Class III restorations.

Effects of Epigallocatechin-3-gallate (EGCG) on the bond strength of fiber posts to Sodium hypochlorite (NaOCl) treated intraradicular dentin

This study was to evaluate the effect of Epigallocatechin-3-gallate (EGCG) on the bond strength of two adhesive systems to the Sodium hypochlorite (NaOCl) treated intraradicular dentin. The roots were accepted regular root canal treatments and post space preparations, and further divided into eight groups according to the four post space pretreatments and two dentin adhesives [Single Bond 2 (SB2) and Clearfil SE Bond (CSB)] used. The push-out strength before and after thermocycling in different root region (coronal and apical), DC of the adhesive and morphologic patterns of treated post space were evaluated. NaOCl + EGCG groups showed the highest push-out strength regardless of the adhesive type, root region and time (P < 0.05). NaOCl pretreatment significantly decreased the push-out strengths and DC of CSB (P < 0.05). EGCG could improve the bonding properties of both SB2 and CSB to NaOCl treated intraradicular dentin. The effect of NaOCl on bonding of a fiber post depended on the type of the adhesive.

Laboratory evaluation of the effect of unfilled resin after the use of self-etch and total-etch dentin adhesives on the Shear Bond Strength of composite to dentin.

BackgroundBased on the frequent application of composite resins as tooth-colored fillings, this method is considered a viable alternative to dental amalgam. However, this method has the low bond strength of the composite to dentin. To solve this issue, various dental adhesive systems with different characteristics have been developed by dentistry experts.AimTo assess the effect of an additional layer of unfilled resin in self-etch and total-etch dentin adhesives on the shear bond strength (SBS) of composite to dentin. Moreover, we assessed the effects of sample storage in artificial saliva on the SBS of composite to dentin.MethodsMethods: This experimental study was conducted on 160 freshly extracted human first or second premolar teeth, which were randomly divided into 16 groups. The teeth were prepared from Mashhad University of Medical Sciences, Mashhad, Iran (2008–2009). Scotchbond Multi-purpose (SBMP), single bond (SB), Clearfil SE Bond, and Clearfil S3 Bond were applied to dentin surface with or without the placement of hydrophobic resin (Margin Bond) in accordance with the instructions of the manufacturers. To expose the coronal dentin, the teeth were abraded with 600 grit SiC paper. Immediately after restoration, half of the samples were tested in terms of SBS, while the other samples were evaluated in terms of SBS after three months of storage in artificial saliva. SBS rates of dental composites evaluated by universal testing machine and samples were studied by optical stereomicroscopy to verify the failure type. Data analysis was performed in SPSS V.16 using Kolmogorov-Smirnov test, independent-samples t-test, ANOVA, and Duncan’s logistic regression test.ResultsIn this study, a significant reduction was observed in the SBS rates of SB and S3 bond adhesive systems after storage with and without hydrophobic resin (p>0.000). Without storage in normal saline, a significant increase was observed in the SBS rate of the SE bond (p=0.013). In addition, SBS rate of SBMP significantly increased after storage with hydrophobic resin (p=0.001). Finally, the highest and lowest rates of SBS were observed in the SE and S3 bonds in all the experimental groups, respectively.ConclusionThe effects of using a hydrophobic resin layer on shear bond strength values seem to be effective. The mild self-etch adhesive exhibited the best resin-dentine bond strength after aging

Self-Etch Adhesive as a Carrier for ACP Nanoprecursors to Deliver Biomimetic Remineralization.

Lab biomineralization should be carried out in an actual clinical practice. This study evaluated self-etch adhesive as a carrier for amorphous calcium phosphate (ACP) nanoprecursors to continuously deliver biomimetic remineralization of self-assembly type I collagen and demineralized dentin. Si-containing ACP particles (Si-ACP) stabilized with polyaspartic acid (PAsp) were synthesized and characterized by transmission electron microscopy (TEM), scanning electron microscopy-energy-dispersive X-ray spectroscopy, Fourier transform infrared analysis, X-ray powder diffractometry, and X-ray phototelectron spectroscopy. The biomimetic remineralization of single-layer reconstituted type I collagen fibrils and demineralized dentin was analyzed by using two one-bottle self-etch dentin adhesives (Clearfil S3 Bond (S3), Kurraray-Noritake; Adper Easy One (AEO), 3 M ESPE) as a carrier loaded (or not, in the case of the control) with 25 wt % of Si-ACP particles. In vitro cytotoxicity assessed by the Cell Counting Kit-8 indicated that the Si-ACP particles had no adverse effect on cell viability. The capacity for Ca and P ions release from cured Si-ACP-containing adhesives (S3, AEO) was evaluated by inductively coupled plasma-atomic emission spectrometry, revealing the successively increasing release of Ca and P ions for 28 days. The intra- and extrafibrillar remineralization of type I collagen and demineralized dentin was confirmed by TEM and selected-area electron diffraction when the adhesives were used as a carrier loaded with Si-ACP particles. Therefore, we propose self-etch adhesive as a novel carrier for ACP nanoprecursors to continuously deliver biomimetic remineralization.

Adhesive interfacial characteristics and the related bonding performance of four self-etching adhesives with different functional monomers applied to dentin

ObjectivesTo examine the interfacial chemical and morphological characteristics of four self-etching adhesives bonded to dentin with different functional monomers. Further, to evaluate the effects of this interaction between functional monomers and dentin on short-term in vitro bonding performance of the four adhesives. MethodsClearfil SE Bond (CSE) and Scotchbond Universal (SU) containing 10-methacryloxydecyl dihydrogen phosphate (10-MDP), Optibond XTR (OX) containing glycero-phosphate dimethacrylate (GPDM), and Adper Easy One (AEO) containing 6-methacryloyloxyhexyl dihydrogen phosphate (6-MHP) were applied to the dentin surface according to the instructions supplied with each. Interaction between the functional monomers and dentin was characterized using thin-film X-ray diffraction (TF-XRD) and scanning electron microscopy (SEM). The hydrophilicity of each acidic monomer was also assessed by chemical structure drawing software. Micro-tensile bond strength (μTBS) and nanoleakage were used to evaluate the bonding effectiveness of the adhesives, either immediately or after thermo-cycling (5°C–55°C) for 5000 cycles. ResultsTF-XRD showed that both CSE and SU exhibited 10-MDP–Ca nano-layering at the adhesive interface, but with different intensity when reacted with dentin. OX, that contains GPDM, demineralized the dentin surface more severely, forming long resin tags into the dentinal tubules, and gained the highest μTBS at the immediate time-point. Thermo-cycling adversely affected the μTBS and nanoleakage of AEO and OX, but had no significant influence on CSE and SU which contain 10-MDP. ConclusionsSelf-etching adhesives containing different structures/concentrations of functional monomers produced adhesive interfaces with obviously different chemical and morphological characteristics, which may have a direct impact on bonding effectiveness. Clinical SignificanceOur findings support the concept that the stable chemical bonding produced by 10-MDP to the Ca of hydroxyapatite is advantageous for durability of adhesive–dentin bonds. In contrast a higher immediate bond strength was achieved with the functional monomer GPDM that etched and wetted the dentin surface better.

СHANGE OF THE MICROSTRUCTURE OF ENAMEL AND DENTIN UNDER THE INFLUENCE OF THE ROTARY TOOL IN THE TREATMENT OF CARIES (IN VITRO STUDY)

At the present stage of development of the basic tool for cutting of necrotic tissues and forming, a cavity in the treatment of dental caries remains a rotary tool. Since the main dental restoration technique is adhesive technology, the quality of the enamel and dentin adhesive surfaces plays a decisive role in the future as a treatment. In vitro, using scanning electron microscopy was studied impact complex of hard teeth tissues preparation components (type cutting tool drive, feed rate, etc.) on the microstructure of adhesive enamel and dentin surfaces. Modeled and rendered the most frequently committed errors by doctors at preparing dental hard tissues. Diamond tool in combination with the turbine drive has the most adverse effect on the microstructure of dentin. Inadequate selection of tungsten carbide tools leads to significant destruction of enamel prisms, which in turn is responsible for violations of the adhesion of filling materials and recurrent caries. Just complete an adequate combination of the above components of hard teeth tissues preparation provides the necessary condition of the adhesive surfaces and high-grade quality of the composite adhesion.

Chlorhexidine-Loaded Amorphous Calcium Phosphate Nanoparticles for Inhibiting Degradation and Inducing Mineralization of Type I Collagen.

A major shortcoming of contemporary dentin adhesives is their limited durability. Exposed collagen fibrils within the bonding interface are degraded by matrix metalloproteinases (MMPs), resulting in aging of the resin-dentin bond. In this study, chlorhexidine-loaded amorphous calcium phosphate (ACP) nanoparticles were synthesized to induce the mineralization of collagen fibrils. The nanoparticles sustainably released chlorhexidine to inhibit MMPs during mineralization. Three types of ACP nanoparticles were prepared: N-ACP containing no chlorhexidine, C-ACP containing chlorhexidine acetate, and G-ACP containing chlorhexidine gluconate, which had a higher drug-loading than C-ACP. Scanning and transmission electron microscopy indicated that the synthesized nanoparticles had diameters of less than 100 nm. Some had diameters of less than 40 nm, which was smaller than the width of gap zones in the collagen fibrils. Energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and high performance liquid chromatography confirmed the presence of chlorhexidine in the nanoparticles. X-ray diffraction confirmed that the nanoparticles were amorphous. The drug loading was 0.11% for C-ACP and 0.53% for G-ACP. In vitro release profiles indicated that chlorhexidine was released sustainably via first-order kinetics. Released chlorhexidine inhibited the degradation of collagen in human dentine powder, and its effect lasted longer than that of pure chlorhexidine of the same concentration. The ACP could induce the mineralization of self-assembled type I collagen fibrils. The chlorhexidine-loaded ACP nanoparticles sustainably released chlorhexidine and ACP under appropriate conditions. This is useful for inhibiting degradation and inducing the mineralization of dentine collagen fibrils.

Progress on matrix metalloproteinase inhibitors

Continuing advances in dentin bonding technology and adhesives revolutionized bonding of resin-based composite restorations. However, hybrid layers created by contemporary dentin adhesives present imperfect durability, and degradation of collagen matrix by endogenous enzymes is a significant factor causing destruction of hybrid layers. Bond durability can be improved by using enzyme inhibitors to prevent collagen degradation and to preserve integrity of collagen matrix. This review summarizes progress on matrix metalloproteinase inhibitors (including chlorhexidine, ethylenediaminetetraacetic acid, quaternary ammonium salt, tetracycline and its derivatives, hydroxamic acid inhibitors, bisphosphonate derivative, and cross-linking agents) and suggests prospects for these compounds.

Probing the neutralization behavior of zwitterionic monomer-containing dental adhesive

ObjectiveTo investigate the polymerization kinetics, neutralization behavior, and mechanical properties of amine-functionalized dental adhesive cured in the presence of zwitterionic monomer, methacryloyloxyethyl phosphorylcholine (MPC). MethodsThe control adhesive was a mixture based on HEMA/BisGMA/2-N-morpholinoethyl methacrylate (MEMA) (40/30/30, w/w/w). The control and experimental formulations containing MPC were characterized with regard to water miscibility of liquid resins, photopolymerization kinetics, water sorption and solubility, dynamic mechanical properties and leachables from the polymers (aged in ethanol). The neutralization behavior of the adhesives was determined by monitoring the pH of lactic acid (LA) solution. ResultsThe water miscibility decreased with increasing MPC amount. The water sorption of experimental copolymer specimen was greater than the control. The addition of 8wt% water led to improved photo-polymerization efficiency for experimental formulations at MPC of 2.5 and 5wt%, and significant reduction in the cumulative amounts of leached HEMA, BisGMA, and MEMA, i.e. 90, 60 and 50% reduction, respectively. The neutralization rate of MPC-containing adhesive was faster than control. The optimal MPC concentration in the formulations was 5wt%. SignificanceIncompatibility between MEMA and MPC led to a decrease in water miscibility of the liquid resins. Water (at 8wt%) in the MPC-containing formulations (2.5–5wt% MPC) led to higher DC, faster RPmax and significant reduction in leached HEMA, BisGMA, and MEMA. The neutralization rate was enhanced with the addition of MPC in the amine-containing formulation. Promoting the neutralization capability of dentin adhesives could play an important role in reducing recurrent decay at the composite/tooth interface.

The effect of double-coating and times on the immediate and 6-month dentin bonding of universal adhesives.

The purpose of this study was to evaluate the effect of double-application coats and times on microtensile bond strength (μTBS) and adhesive-dentin interfaces created by dentin adhesive systems after 6 months of storage in water. Two-hundred sixteen extracted non-carious human third molars were selected for the study. Single-Bond Universal (SU) and All-Bond Universal (AU), Adper Easy One (Eo) Self-Etch adhesive and Adper Single-Bond2 (Sb) etch-and-rinse adhesive were applied to a flat dentin surface using three methods (1): dentin adhesives were applied as recommended by the manufacturers; (2): two consecutive coats of dentin adhesives were applied before photo-polymerization; and (3): a single coat of adhesive was applied but with twice the manufacturers recommended application time. Microtensile bond strength was determined either immediately or after 6 months of water storage. Data were analyzed using one-way analysis of variance and Tukey's post-hoc tests. At 24 h, groups 1, 2, and 3 exhibited statistically similar results for all dentin adhesive systems. For AU-Er, group3 showed significantly higher bond strength than all group of AU-Se after 6 months. Universal adhesives seemed more stable against water degradation than traditional two-step etch-and-rinse and all-in-one systems within the 6-month period.

Effects of Artificial Saliva Contamination on the Bond Strength of Three Dentin Adhesives to Dentin of Primary Teeth

본 연구의 ëª©ì ì€ ìœ ì¹˜ 상아질의 ë³µí•©ë ˆì§„ ìˆ ì‹ì—ì„œ 각 단계별로 치면에 인공타액이 오염되었을 때와 이것을 ì œê±°í•˜ëŠ” 방법이 한 단계 자가부식 ì ‘ì°©ì œì™€ 두 단계 산 부식 ì ‘ì°©ì œì˜ 결합강도에 미치는 영향을 비교 분석하는 것이다.연구 ëª©ì ì„ 달성하기 위해, ê±´ì „í•œ ìœ êµ¬ì¹˜ 42개를 ì„ ì •í•˜ì—¬ 세 ì¢ ë¥˜ì˜ 상아질 ì ‘ì°©ì œì¸ Scotchbond Universal Adhesive(SBU), All-Bond Universal(ABU)ê³¼ Prime & Bond NT(PNT)에 따라 3개의 군으로 분류하였다. 이를 다시 각 ì ‘ì°©ì œì—ì„œ 7개의 하위 그룹으로 나누었다. 대조군인 1군을 ì œì™¸í•œ 나머지 군은 인공타액으로 오염시킨 군으로 다음과 같이 분류하였다: 2, 3êµ° - ì ‘ì°©ì œ 도포 ì „; 4, 5êµ° - ì ‘ì°©ì œ 중합 ì „; 6, 7êµ° - ì ‘ì°©ì œ 중합 후. 인공타액은 수세, ê±´ì¡°(2, 4, 6êµ°)와 ê±´ì¡°(3, 5, 7êµ°)로 ì œê±°í•˜ì˜€ë‹¤. 처치된 치면에 ë³µí•©ë ˆì§„(Filtek, Z-350)으로 ìˆ˜ë³µí•˜ê³ ì‹œíŽ¸ì„ ì œìž‘í•œ 후 미세인장 결합강도(Microtensile bond strength, MTBS)를 ì¸¡ì •í•˜ì˜€ë‹¤. One-way ANOVA와 Tukey HSD test를 이용해서 통계분석을 실시하였다(p < 0.05).대조군에서 MTBS의 í‰ê· ê°’ì€ PNT가 ABU와 SBU에 비해 높게 나타났다(p < 0.001). 세 가지 ì ‘ì°©ì œì˜ 각 오염단계에서 수세와 건조를 시행했을 때(2, 4, 6êµ°)가 건조만 시행했을 때(3, 5, 7êµ°)보다 높은 결합강도를 나타내었다. ê·¸ë¦¬ê³ ì ‘ì°©ì œ 중합 ì „ 단계에서 인공타액의 오염이 발생했을 때(4, 5êµ°)는 대조군에 비해 낮은 MTBS를 보였다(p < 0.001).ì „ë°˜ì ìœ¼ë¡œ 두 단계 산 부식 ì ‘ì°©ì œê°€ 한 단계 자가부식 ì ‘ì°©ì œì— 비해 높은 MTBS를 보였다. ì ‘ì°©ì œë¥¼ 중합하기 ì „ 단계에서 인공타액에 오염되었을 경우에는 ì ‘ì°© 강도가 í˜„ì €ížˆ ê°ì†Œí•˜ì˜€ê³ , 수세와 ê±´ì¡° ê³¼ì •ìœ¼ë¡œ ì ‘ì°©ê°•ë„ë¥¼ íšŒë³µí• ìˆ˜ 없었다.

Effect of a one-step self-etch adhesive on endogenous dentin matrix metalloproteinases.

Degradation of the hybrid layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the hybrid layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the hybrid layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the hybrid layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time.

Effect of Qmix and Other Irrigants on Dentin Adhesives in Pulp Chambers of Primary Teeth: SEM Study.

To compare the effect of different endodontic irrigants on microleakage of adhesives used within pulp chamber of primary molars. 72 Primary molars were divided into 6 groups, according to 3 irrigants and 2 adhesives used. After de-roofing the pulp chamber, pulp was extirpated. In 36 samples, pulp chambers were bonded with Xeno V+ after irrigation with either QMix (Group1); 17%EDTA+5%NaOCl (Group2) or normal saline (Group3) and in other half samples, pulp chambers were bonded with SinglebondUniversal after irrigation with either QMix (Group 4); 17%EDTA+5% NaOCl (Group5) or normal saline (Group 6). All the samples were restored with Filtek Z350. Ten teeth from each group were assessed for dye penetration. Two samples in each group were viewed under scanning electron microscope. Data was statistically analyzed using Mann-Whitney and Kruskal Wallis tests at a significance level of P < 0.05. Mean microleakage scores were: Group 1-1.5±0.70, Group 2-1.6±.51, Group 3-2.4±0.96, Group 4-1.2±0.42, Group 5-1.2±0.42, Group 6-1.1±0.32. Irrigation with QMix significantly reduced the microleakage of XenoV+ but had no significant effect on microleakage of SinglebondUniversal. Irrigation with EDTA/NaOCl or QMix had no detrimental effect on the sealing ability of either of the adhesive tested.

Treatment of dentinal hypersensitivity by using dentinal adhesives

Treatment of dentinal hypersensitivity by using dentinal adhesives

Effect of acrolein-based primer as collagen cross-linker on dentin adhesion

Effect of acrolein-based primer as collagen cross-linker on dentin adhesion

Pulp Response following Direct Pulp Capping with Dentin Adhesives and Mineral Trioxide Aggregate; An Animal Study.

Introduction:Pulp vitality and its continuous dentin prodution are essential for long-term success of direct pulp capping (DPC). The aim of present study was to evaluate the histopathological response of the canine pulp following DPC using either different dentin adhesive resins (DAR), calcium hydroxide (CH) or mineral trioxide aggregate (MTA). Methods and Materials:DPC was done on 72 dog’s teeth using 6 types of dental materials (n=12) (4 types of DAR, white MTA and CH). Therefore, six healthy dogs were anesthetized and 2 teeth from each dog were allocated to either type of mentioned DPC agents. The dental pulps were exposed mechanically by drilling in the center of class V cavities. The different types of capping materials included DARS (Clearfil S3 Bond, Optibond FL, Single Bond and Clearfil SE Bond), white MTA and CH. After 7, 21 and 63 days, two dogs were euthanized in each interval. Microscopic evaluations were done according to following criteria: intensity of inflammation, presence of necrosis and formation of hard tissue. The recorded data were analyzed by the Kruskal-Wallis, Friedman, Cochran’s and Fisher’s exact tests using SPSS software version 12 at significant level of 0.05. Results:No significant differences were found regarding necrosis among DPC materials (P>0.05). However, MTA caused higher amount of hard tissue formation after 63 days in comparison with 21 days. Conclusion:MTA provided the highest degree of hard tissue formation after 63 days. However, further studies should be performed for administering a definitive material.

Enamel and Dentin Adhesion Differences

Enamel and Dentin Adhesion Differences

Classification review of dental adhesive systems: from the IV generation to the universal type.

Adhesive dentistry has undergone great progress in the last decades. In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which relies on the effectiveness of current enamel-dentine adhesives. Adhesive dentistry began in 1955 by Buonocore on the benefits of acid etching. With changing technologies, dental adhesives have evolved from no-etch to total-etch (4th and 5th generation) to self-etch (6th, 7th and 8th generation) systems. Currently, bonding to dental substrates is based on three different strategies: 1) etch-and-rinse, 2) self-etch and 3) resin-modified glass-ionomer approach as possessing the unique properties of self-adherence to the tooth tissue. More recently, a new family of dentin adhesives has been introduced (universal or multi-mode adhesives), which may be used either as etch-and-rinse or as self-etch adhesives. The purpose of this article is to review the literature on the current knowledge for each adhesive system according to their classification that have been advocated by many authorities in most operative/restorative procedures. As noted by several valuable studies that have contributed to understanding of bonding to various substrates helps clinicians to choose the appropriate dentin bonding agents for optimal clinical outcomes.

Influence of blood contamination during multimode adhesive application on the microtensile bond strength to dentin.

The present study evaluated the effects of blood contamination performed at different steps of bonding on the microtensile bond strength (μTBS) of multimode adhesives to dentin when using the self-etch approach. Seventy-five molars were randomly assigned to three adhesive groups comprising 25 specimens each: two multimode adhesives [Single Bond Universal (SBU) and All-Bond Universal (ABU)] and a conventional one-step self-etch adhesive [Clearfil S3 Bond Plus (CSBP)]. Each group was subdivided as follows: (1) uncontaminated (control): bonding application/light curing as a positive control; (2) contamination-1 (cont-1): bonding application/light curing/blood contamination/dry as a negative control; (3) contamination-2 (cont-2): bonding application/light curing/blood contamination/rinse/dry; (4) contamination-3 (cont-3): bonding application/blood contamination/dry/bonding re-application/light curing; and (5) contamination-4 (cont-4): bonding application/blood contamination/rinse/dry/bonding re-application/light curing. Dentin specimens were prepared for μTBS testing after the composite resin application. Data were analyzed with two-way ANOVA and post-hoc tests (α = 0.05). μTBS values were similar in cont-3 groups, and ABU/cont-4 and corresponding control groups, but were significantly lower in the other groups than in their control groups (P < 0.05). Cont-1 groups showed the lowest μTBS values (P < 0.05). Neither decontamination method prevented the decrease in μTBS when contamination occurred after light curing. Drying the blood contaminants and reapplying the adhesive may regain the dentin adhesion when contamination occurs before light curing. Alternatively, rinsing and drying contaminants followed by adhesive re-application may be effective depending on adhesive type.