XP Bond Research Articles

Randomized prospective clinical trial of class II restorations using flowable bulk-fill resin composites: 4-year follow-up.

This randomized, prospective, and split-mouth study aimed to evaluate flowable bulk-fill resin composites in class II restorations, comparing it with a conventional layering technique after 4-year follow-up. Fifty-three subjects received three class II restorations according to the restorative systems: conventional microhybrid composite resin (PA - Peak Universal + Amelogen Plus, Ultradent); flowable bulk-fill and nanoparticulate composite resins (ABF - Adper Single Bond 2 + Filtek Bulk Fill Flow + Filtek Z350XT, 3M/Espe); and flowable bulk-fill and microhybrid composite resins, (XST - XP Bond + SDR + TPH3, Dentsply). The clinical performance and interproximal contacts were evaluated. Statistical analyses were performed using the Kaplan-Meier, equality test of two proportions, Friedman, Wilcoxon, Kruskal-Wallis, Mann-Whitney, and Logistic regression analysis tests (alpha = 0.05). In total, 106 restorations were evaluated at 4 years. Both systems with bulk-fill composites presented higher marginal discoloration than PA. About surface texture, ABF restorative system showed superior bravo scores being statistically similar to XST. Better performance for wear and surface staining was found for XST restorative system. All restorative systems resulted in the decreased interproximal contacts, occurring early for XST. The restorative systems that used flowable bulk-fill resin composites showed satisfactory clinical performance compared with conventional resin composite after 4 years. All restorative systems had decreased proximal contact after 4 years. Initial marginal discoloration was observed in more than 50% of class II restorations performed with restorative systems that used flowable bulk-fill resin composite. All restorative systems had decreased proximal contact strength over time.

Three-year Randomized Prospective Clinical Trial of Class II Restorations Using Flowable Bulk-fill Resin Composites.

This randomized, prospective, and split-mouth study aimed to evaluate flowable bulk-fill resin composites in class II restorations and to compare with a conventional layering technique after a 3-year follow-up. Fifty-three subjects received three class II restorations according to the restorative systems: conventional microhybrid resin composite (PA, Peak Universal + Amelogen Plus, Ultradent), flowable bulk-fill and nanoparticulate resin composites (ABF, Adper Single Bond 2 + Filtek Bulk Fill Flow + Filtek Z350XT, 3M Oral Care), and flowable bulk-fill and microhybrid resin composites (XST, XP Bond + SDR + TPH3, Dentsply). The clinical performance and interproximal contacts were evaluated. Statistical analyses were performed using the equality test of two proportions, Logistic regression analysis, Friedman, Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests (a=0.05). Forty-seven patients were evaluated at 3 years. XST bulk-fill restorative system presented higher marginal discoloration than PA, and the opposite occurred for surface staining. All restorative systems resulted in decreased interproximal contacts, occurring early for XST. Although the restorative system using incremental technique presented better performance for marginal discoloration, one of the restorative systems that used flowable bulk-fill resin composite (XST) showed the lowest surface staining. All restorative systems had decreased proximal contact over time.

Influence of the adhesive bonding protocol on the inflammatory cellular response and gelatinolytic activity in human teeth

The aim of this paper was to assess the biocompatibility and expression of metalloproteinase -9 of two dentin bonding agents in human teeth, using different methods of dentin pre-treatment and different time intervals. Deep Class I cavities were prepared on the occlusal surface of 18 sound molars. Restorations were performed with XP Bond™ (Dentsply) and Futurabond® DC (VOCO). After 30, 90 or 120 days, the teeth were extracted and processed for histological and immunohistochemical assessment. In XP Bond group, was observed a moderate inflammatory infiltrate and immunoreactivity of metalloproteinase -9 in all storage intervals. In Futurabond DC group, a slight inflammatory infiltrate was found in the first intervals. After 120 days, the inflammatory infiltrate was either slight or absent, while the tissue morphology remained normal. The immunoreactivity of metalloproteinase -9 was considered moderate, except for two specimen after 120 days, that demonstrated no immunoreactivity. Therefore, etch-and-rinse adhesives exhibited a more intense pulpal response than self-etching agents. When performing adhesive restorations in medium and deep cavities in human teeth, the use of a self-etching adhesive strategy should be considered in view of the lower induction of inflammatory and proteolytic activity. Further studies of molecular events should be conducted, taking into consideration the possible inflammatory pulp reactions that can contribute to the success of restorative procedures.

Immunoxpression of MMPs -9, -13 and TIMP-3 after Using Etch-and-rinse Adhesive

The aim of the present study was to determine the expression of MMP-9, MMP-13 and TIMP-3 after using the XP Bond ™ (Dentsply) dentin-bonding agent on 21 human teeth. Class I deep cavities were prepared and restored. After 01, 07, 14, 21, 30, 90 and 120 days, the teeth were extracted and processed for an immunohistochemical assessment (n=3). Immunohistochemical staining was performed using the monoclonal antibody anti-MMP-9, and polyclonal antibodies anti-MMP-13 and anti-TIMP-3. The immunoreactivity of metalloproteinases 9 and 13 was considered intense and moderate in the first storage intervals, before decreasing over time. In contrast, the immunoreactivity of TIMP-3 was considered absent in dentin and weak in pulp in the first time intervals, and completely absent in the subsequent intervals. MMP-9 expression in dentin and in pulp was prevalent in the dentinal tubules and odontoblastic layer, respectively. MMP-13 expression in dentin and in pulp was predominant in the pre-dentine region and odontoblastic layer, respectively. TIMP-3 expression was absent in dentin and predominantly located in the odontoblastic layer for pulp. In conclusion, the expression patterns of MMP-9, MMP-13 and TIMP-3 altered in the different time intervals studied. The increased expression of TIMP-3 in the first time intervals could suggest a synchronous response to the increased expression of MMPs in the same periods. The results confirmed the low performance of TIMP-3 in the physiological processes of the pulp-dentin complex for the conditions and materials tested herein.

Dentin Cross-linking Effect of Carbodiimide After 5 Years

Carbodiimide (EDC)–based dentin primers preserve hybrid layer (HL) integrity. However, aging >1 y has not been investigated. The present study examined whether the cross-linking effect of EDC was reflected in dentin bond strength, endogenous enzymatic activity, and the chemical profile of the HL after 5-y aging in artificial saliva. Noncarious human third molars (N = 42) were cut to expose middle/deep coronal dentin and treated as follows: group 1, dentin etched with 35% H3PO4, pretreated with a 0.3M aqueous EDC primer for 1 min and restored with XP Bond (Dentsply Sirona); group 2, as in group 1 but without EDC pretreatment; group 3, Clearfil SE Bond (Kuraray-Noritake) primer applied to dentin surface, followed by EDC pretreatment as in group 1 and application of bond; group 4, as in group 3 without EDC pretreatment. After composite buildup, the specimens were cut into sticks or slabs, depending on the experiment. All tests were performed at baseline (T0) and after 5 y of aging (T5) in artificial saliva at 37 °C. Microtensile bond strength (µTBS) was tested at a crosshead speed of 1 mm/min until failure. Endogenous enzymatic activity was investigated with in situ zymography. The chemical profile of HL was determined via Raman spectroscopy. Three-way analysis of variance and post hoc Tukey test were used to analyze µTBS and in situ zymography data (α = 0.05). EDC pretreatment and aging significantly influenced µTBS and in situ zymography results (P < 0.05). Higher bond strength and lower gelatinolytic activity were identified in the EDC-treated groups at T5 (P < 0.05), especially in the etch-and-rinse groups. Raman spectra revealed less defined amide III peaks in control specimens at T5. The EDC cross-linking effect persisted in the HL for 5 y in terms of bond strength, collagen structure preservation, and dentinal enzyme silencing.

Ocena laboratoryjna materiałów używanych do uszczelniania zagłębień anatomicznych w zębach stałych niedojrzałych

Introduction. Pit and fissure sealing is highly efficient in caries prevention. New types of composite materials – self-adhesive and bulk fill materials – are interesting alternatives to standard resin-based sealants. Their specific features may contribute to the clinical success of the sealing procedure. The requirement for a successful procedure is an adequate seal of the material to prevent bacterial microleakage. Aim. The aim of this study is the laboratory evaluation of the degree of filling of fissures by the tested materials and the occurrence of gaps between the materials and enamel. Material and methods. Fissures of 15 permanent third molars were sealed with the following materials: Helioseal F (Ivoclar Vivadent), Vertise Flow (Kerr) and SDR (Dentsply Sirona) with XP Bond (Dentsply Sirona). The specimens were embedded in epoxy resin and cut. Images were taken using a scanning electron microscope. An evaluation of the degree of fissure filling and material adaptation was performed in a graphic software. Statistical analysis was performed. Results. A total of 22 samples were evaluated: 7 Helioseal F, 7 Vertise Flow and 8 SDR. SDR had the highest percentage of fissure filling depth (0.808), followed by Vertise Flow (0.614) and Helioseal F (0.602). The highest percentage of fissure fill area was characterized by SDR at 0.938, followed by Helioseal F at 0.872 and Vertise Flow at 0.799. No statistically significant differences were observed between the results. The percentage of inadequate material adaptation was 0 for SDR, 0.069 for Vertise Flow and 0.149 for Helioseal F. There was a statistically significant difference between Helioseal F and SDR material. Conclusions. The degree of fissure filling by all tested materials is comparable, while the degree of adaptation of the materials to the enamel surface is statistically different when comparing SDR to Helioseal F, in favor of SDR.

Results of electrometric assessment of quality of marginal fit of composite material to hard tissues of teeth in various clinical conditions

The purpose of the study was a clinical electrometric assessment of the quality of the marginal fit of the composite material to the hard tissues of the tooth, depending on the type and amount of adhesive used the influence of the adhesive, namely: the mechanism of its action and quantity, on the quality of restoration of the hard tissues of the tooth lost by the carious process in the composite material over time.Material and methods. In clinical conditions, 140 fillings were examined, the placement of which was carried out only in cavities of classes 1 and 2, with the area affected by the carious process of hard tooth tissues from 30 to 50 mm2. For this, composite material ESTET X and adhesive systems were used: one-component XP BOND and self-etching XENO V in different volumes (6.6 and 17.7 mg). To assess the marginal fit of the filling material to the hard tissues of the tooth, the multifunctional electro-diagnostic device EST-DENT (Geosoft, Russia) was used. The principle of operation of the device is based on measuring the strength of the current flowing through the hard tissues of the tooth under the influence of a low-voltage source of electrical power. Results. The quality of the marginal fit of composite fillings to the hard tissues of the tooth, which is the main factor determining the durability of their functioning, largely depends on the amount of adhesive used, its mechanism of action, the area and depth of the carious lesion of dentin. Over time, there is a change in the structure obtained as a result of the mechanical and chemical interaction of the adhesive system and hard tissues of the tooth (primarily the hybrid layer), in the direction of decreasing its density and breaking integrity. This in turn increases the amount of electric current passing through it.Conclusions. An analysis of the obtained clinical data shows that when restoring hard tissues of teeth lost over large areas and located close to the pulp cavity of the coronal part of the tooth, it is necessary to take into account the effect of dentinal fluid on the quality and durability of the restoration. The use in these cases of adhesive systems in an amount of not less than 17.7 mg (a drop from dispenser), careful preparation of the affected tooth tissues, rational design of the formed cavity, strict adherence to the manufacturer’s recommendations on the time of use of the adhesive. can significantly reduce the risk of unsatisfactory treatment results.

Comparative assessment of the human blood plasma impact on the properties of various adhesive systems

To assess the degree of influence of human blood plasma simulating dentinal fluid on the composite resin adhesion to dental hard tissues. The strength of the adhesive bond between the composite material and dental hard tissues was studied using a shear test machine Zwick Roell Z 010 («Zwick», Germany) on extracted human teeth. XP Bond one-component adhesive system and XENOV self-etching adhesive system (DENTSPLY, Germany), high-definition micrometric restoration material Esthet X HD (DENTSPLY, Germany), as well as centrifuged blood plasma were used. Adhesion strength decreased by 26-78% when blood plasma weighing from 0.2 to 2.0 mg mixed up the self-etching system (weight 6.6 mg). A significant decrease in the adhesion force occurred when plasma with a mass of 0.7 mg or more mixed up with the monomer (a decrease in adhesion by 19.1%). A critical decrease in the adhesion force (43% or more) occurred with the mixture of blood plasma weighing 2.0 mg or more.

The results of evaluating the degree of influence of human blood plasma on the strength of adhesion of composite material to dentin (one-component adhesive system)

To study the dynamics of changes in the adhesion between the composite and dentin of the tooth when using different volumes of a single-component adhesive system in case of contamination of it with human blood plasma. To achieve this goal, the following were used: extracted human teeth, XP Bond one-component adhesive systems (DENTSPLY, Germany), Esthet X HD micrometric restoration material (DENTSPLY, Germany), and centrifuged blood plasma. The strength of the adhesive bond between the composite material and the hard tissues of the tooth was studied using a shear test machine Zwick Roell Z 010 («Zwick», Germany). The use of a single-component adhesive system in an amount of 17.7 mg (1 drop from a dispenser) for treating open dentin makes it more resistant to contamination compared to using the same adhesive, but in an amount of 6.6 mg (the amount of adhesive that adsorbs a medium-sized dental take). A decrease in the adhesion force between the composite material and tooth hard tissues from 1.5 to 17.7% occurs when a single-component adhesive system weighing 17.7 mg of blood plasma simulating a dentinal fluid weighing from 0.2 to 2.0 mg enters. The ingestion of the same amount of blood plasma in a single-component adhesive system weighing 6.6 mg leads to a decrease in its adhesion from 4.3 to 43%.

Push-out Bond Strength of Fiber Posts Cemented Using New Universal Adhesives on Etched and Nonetched Intraradicular Dentin

The aim of this study was to assess if the curing mode and the etching mode could affect the push-out bond strength of different post cementation systems using two universal adhesives. A total of 100 single-rooted teeth were divided into Prime & Bond Elect (PBE), Prime & Bond Active (PBA), and Prime & Bond XP (PBXP) as a control. The PBE, PBA, and PBXP were used in the self-etch (SE) and etch and rinse (E&R) mode. Post cementation was performed using Core X flow used in dark-cure and in light-cure. Data were analyzed using the one-way ANOVA test and post hoc Bonferroni and Dunnet tests. The Student's t test was performed to find significance between two independent groups. Bond strength was significantly influenced by the adhesive strategies. The PBE and PBA obtained higher values when used in the SE mode (p < 0.001). Light-cured groups obtained significantly higher values (p < 0.001) compared to dark-cured groups. The post space region also had a significant effect on the bond strength; the apical third recorded lower values in all groups (p < 0.001). The PBA and PBE universal adhesives obtained higher PBS values when used in the SE mode and followed by the light-curing of resin cement. Universal adhesives represent a good alternative to the conventional total-etch adhesive system for fiber post cementation. Since they perform better in SE, they would be recommendable in clinical practice, as they can be used with a simplified technique.

Shear bond strength of different materials used for pit and fissure sealing

Introduction. Pit and fissure sealing is a effective procedure in preventing caries, as proven in numerous clinical trials. Materials used for this technique are usually resin-based fissure sealants, but some studies suggested using flowable composites as well. The latest generations of these materials include self-adhesive flowable composites and bulk fill composites. Retention of these materials is one of the main factors that contribute to caries prevention. Therefore, shear bond strength tests that determine the material’s ability to bond with the enamel may help determine their clinical effectiveness. Aim. The aim of the study was to assess the shear bond strength to the enamel of the following materials: Helioseal F (Ivoclar Vivadent), Vertise Flow (Kerr), and SDR (Dentsply Sirona) with XP Bond (Dentsply Sirona). Material and methods. 15 permanent third molars extracted for orthodontic reasons with prepared flat enamel surfaces were randomly divided into three groups. Tested materials ? Helioseal F, Vertise Flow and SDR with XP Bond were polymerised on these surfaces, using a mould. Samples were immersed in distilled water, kept at 37°C for 24 h, and then installed in an Instron testing machine. The machine stopped at sample fracture and the load was recorded. Shear bond strengths were calculated. Statistical analysis was performed. Also, samples were assessed using an optical microscope to assess sample failure type. Results. 35 samples, including 11 Helioseal F, 12 Vertise Flow, and 12 SDR were analysed. SDR with XP bond had the highest shear bond strength ? 23.70 (± 6.35) MPa; Vertise Flow ? 20.10 (± 3.95) MPa, and Helioseal F the lowest ? 15.93 (± 3.17) MPa. There was a statistically significant difference between flowable composites (SDR and Vertise Flow) and resin-based fissure sealant (Helioseal F). There were 18 cohesive sample fractures within the enamel, 14 adhesive fractures and 4 mixed. Conclusions. The shear bond strength of SDR with XP Bond and Vertise Flow is statistically significantly higher than that of Helioseal F. However, it is also crucial to clinically assess the effectiveness of these materials.

One-year bonding performance of one-bottle etch-and-rinse adhesives to dentin at different moisture conditions

This study aimed to investigate the one-year bond strengths to dentin of one-bottle etch-and-rinse adhesive systems applied under different moisture conditions. Class V cavities were prepared in bovine incisors and randomly allocated (n = 8) according to the type of adhesive system used – SB (Adper™ Single Bond 2); PB (Prime & Bond 2.1); and XPB (XP Bond) – and the moisture condition kept in the cavity – moist, over-wet, and over-dry. Filtek™ Z250 was used for teeth restoration. Specimens for microtensile bond strength (µTBS) test were obtained and stored in water for 24 h or 1 year, and submitted to mechanical testing. Data were analyzed using t-tests, ANOVA and the Holm–Sidak post hoc test (α = 0.05). Weibull analysis was used to verify the reliability of specimens. The type of adhesive and the moisture condition of the substrate affected the µTBS. At 24 h, SB performed better under the moist and over-wet conditions. At 1 year, SB, PB, and XPB showed the greatest percentage reduction at the moist (∼38%), over-wet (100%), and over-dry (100%) conditions, respectively. The reliability of adhesives was affected by the variable factors tested. In conclusion, the solvent composition of adhesives and the moisture condition of the substrate play an important role in the bond strength and bonding stability of resin-based restorations, as well as on the reliability of the adhesive interfaces over time.

Randomized Prospective Clinical Trial of Class II Restorations Using Low-shrinkage Flowable Resin Composite.

The aim of this prospective, randomized, split-mouth clinical trial was to evaluate postoperative sensitivity, clinical performance, and interproximal contacts after using different restorative systems. Fifty-three subjects each received three class II restorations according to the restorative systems: conventional resin composite (PA: Peak Universal+Amelogen Plus, Ultradent), low-shrinkage flowable and nanoparticulate resin composites (ABF: Adper Single Bond 2+Filtek Bulk Fill Flow+Filtek Z350XT, 3M ESPE), and low-shrinkage flowable and microhybrid resin composites (XST: XP Bond+SDR+TPH3, Dentsply). Postoperative sensitivity was assessed at 24 hours, seven days, 90 days, and six months. The clinical performance and interproximal contacts were evaluated at baseline, six months, and one year. Friedman, Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests were used to evaluate postoperative sensitivity and interproximal contacts. The equality test of two proportions and logistic regression analysis were used to assess the clinical performance. No statistically significant differences were observed among groups for postoperative sensitivity. The highest spontaneous sensitivity was reported at 24 hours. ABF was the only group that did not present a reduction in cold sensitivity. Color, marginal discoloration, and superficial staining showed differences among the groups. XST did not show superficial staining after one year. No differences were observed among groups in relation to interproximal contacts. XST resulted in the loss of interproximal contact after one year. Different types of restorative systems do not influence postoperative sensitivity; however, ABF maintained cold sensitivity over time. Marginal discoloration occurred for all groups but occurred earliest for PA. XST presented a reduction of interproximal contact after one year of evaluation.

Dry-bonding to dentin using alternative conditioners based on iron-containing solutions or nitric acid

ObjectivesTo evaluate the effect of experimental conditioners (10–3 solution − 10–3, 6.8% ferric oxalate - FOX, and 1.4% nitric acid - NI) on dentin elastic modulus, flexural strength, bond strength, failure mode, and adhesive interface morphology of two etch-and-rinse adhesives (XP Bond, Dentsply or One-Step, Bisco) applied on etched dry dentin. MethodsSound human third molars were used for the microtensile bond strength test (n = 8), performed at 24 h and after one year of water storage. Failure modes were evaluated by scanning electron microscopy. Dentin bonding interface was analyzed by confocal laser scanning microscopy (n = 3). Adhesive systems were applied on phosphoric acid-etched, wet (positive control) and dry (negative control) dentin, and on etched and dry dentin previously treated with 10–3 (15s), FOX (60s), or NI (15s). Bovine dentin bars (n = 15) were immersed into the conditioning solutions and subjected to a three-point bending test. ResultsXP Bond + 10–3 or NI resulted in lower bond strength than phosphoric acid. One-Step + 10–3 or NI resulted in bond strengths equivalent to the positive control. Experimental conditioners presented no bond strength reduction after one year, regardless of the bonding agent tested. One-Step resulted in more adhesive failures than XP Bond at 24 h, and mixed failures increased after storage. All experimental conditioners promoted hybridization and resin tags formation, except FOX. Dentin elastic modulus was not affected by the conditioners, whereas flexural strength was significantly reduced by FOX. ConclusionsAdequate and stable dentin bonds were achieved when the bonding agents were applied on 10–3 or NI-treated dentin. None of the experimental conditioners reduced dentin elastic modulus, but dentin flexural strength was significantly reduced by FOX-conditioning.

Carbodiimide inactivation of matrix metalloproteinases in radicular dentine

ObjectivesThe present in vitro study evaluated the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), a cross-linking agent used as an additional therapeutic primer for luting fiber posts to radicular dentine to prevent hybrid layer degradation. MethodsRoot canal treatment was performed on 80 extracted single-rooted human teeth. A 10-mm post space was prepared and pecimens were randomly assigned to four groups (n=20) according to the bonding system: 1) All Bond 3 (Bisco); 2) All Bond 3 + 0.3M EDC; 3) Prime&Bond XP (Dentsply Sirona); 4) Prime&Bond XP + 0.3M EDC. In groups 2 and 4, EDC was applied on phosphoric acid-etched dentine for 1 min. Fiber posts (RelyX Fiber Post, 3M ESPE) were luted with a dual-cured resin cement (Core-X flow, Dentsply Sirona). Slices were prepared for micro push-out test and interfacial nanoleakage evaluation of the coronal and apical region of the canal space after 24 h and 1 year storage in artificial saliva. In-situ zymography was performed to investigate endogenous matrix metalloproteinase activities within the hybrid layer. Results were statistically analysed with three-way ANOVA test or Chi Square test. Statistical significance was set at α=0.05. ResultsNo significant influence was identified between the two adhesives. The use of EDC significantly improved fiber post bond strength at 1 year but not at 24 h. Application of 0.3 M EDC prior to bonding significantly reduced gelatinolytic activities within the radicular hybrid layers. ConclusionsCarbodiimide was effective in preserving fibre post bond strength over time, through reducing the activities of intra-radicular endogenous proteases. Clinical SignificanceInhibition of matrix metalloproteinases using EDC over radicular dentin could play an important role in bond strength preservation. However, the clinical relevance of these findings needs to be proven.

Evaluation of surface roughness and color change of bovine enamel after immersion in dye solution

Aim: The aim of this in vitro study was to evaluate the influence of dye solution on enamel color change after bleaching protocols and the effectiveness in maintaining the color of these agents.Material and Methods: The buccal surfaces of sixty-five bovine incisors were cleaned and polished, and the enamel specimens were divided into thirteen groups: G1 to G6: treated with 6% hydrogen peroxide using different surface agents; G7 to G12: treated with 15% hydrogen peroxide using different surface agents; G13: control. After 24 hours, the groups treated were immersed in black tea solution; the control group was stored in artificial saliva. The color was evaluated prior to bleaching, 24 hours later and after immersion in the dye solution; the roughness was measured immediately after bleaching, 24 hours later and 7 days after immersion in the dye solution. The data was analyzed using the Kruskal-Wallis test, followed by the Miller test for roughness analysis, and the Duncan test for color change analysis. It was used 5% significant level with p&lt;0.05.Results: The data found in the evaluation of surface roughness after bleaching indicated a reduction of roughness in all the groups. The surface agent Bifluoride, when applied, showed an increase in roughness after its application and it decreases after immersion in dye solution; the surface agent Desensibilize and the XP Bond adhesive showed greater color alteration after immersion in dye solution.Conclusions: All the groups studied, under different whitening technique, were effective in promoting whitening.

Two-year Effects of Chlorhexidine-containing Adhesives on the In Vitro Durability of Resin-dentin Interfaces and Modeling of Drug Release.

To evaluate the effects of addition of diacetate chlorhexidine (CHX) at different concentrations into two etch-and-rinse adhesive systems on CHX release, as well as the immediate (IM) and two-year (2-Y) resin-dentin microtensile bond strength (μTBS) and nanoleakage (NL). CHX was added to XP Bond (XP) and Ambar (AM) at concentrations of 0.0 wt% (control); 0.01 wt%; 0.05 wt%; and 0.1 to 0.2 wt%. To assess the cumulative CHX release, adhesive disks were made in a metallic matrix and after light-curing were stored in water. Ultraviolet spectrophotometric measurements of the storage solution were performed to examine the release kinetics of CHX. For μTBS and NL, the occlusal enamel of molars was removed and the adhesives were applied to the dentin surface after acid etching. After composite resin build-up, specimens were sectioned to obtain μTBS sticks. The specimens were subjected to μTBS and NL at IM and after 2-Y. In addition, specimens underwent examination for CHX using micro-Raman spectroscopy. All data were submitted to statistical analysis (α=0.05). With regard to CHX release, AM showed a slower and gradual release of CHX while XP released CHX more quickly ( p<0.05), and CHX was still present in the hybrid layers after 2-Y. Both adhesives showed CHX release at 2-Y water storage. Both CHX-containing adhesives showed higher μTBS values than did the control group ( p<0.05).

Cross-linking effect on dentin bond strength and MMPs activity

ObjectiveThe objectives of the study were to evaluate the ability of a 1-ethyl-3 (3-dimethylaminopropyl) carbodiimide (EDC)-containing primer to improve immediate bond strength of either self-etch or etch-and-rinse adhesive systems and to stabilize the adhesive interfaces over time. A further objective was to investigate the effect of EDC on the dentinal MMPs activity using zymographic analysis. MethodsFreshly extracted molars (n=80, 20 for each group) were selected to conduct microtensile bond strength tests. The following groups were tested, immediately or after 1-year aging in artificial saliva: G1: Clearfil SE (CSE) primer applied on unetched dentin, pretreated with 0.3M EDC water-solution for 1min and bonded with CSE Bond; G2: as G1 but without EDC pre-treatment; G3: acid-etched (35% phosphoric-acid for 15s) dentin pretreated with 0.3M EDC, then bonded with XP Bond (XPB); Group 4 (G4): as G3 without EDC pre-treatment. Further, gelatinase activity in dentin powder treated with CSE and XPB with and without EDC pre-treatment, was analyzed using gelatin zymography. ResultsThe use of 0.3M EDC-containing conditioner did not affect the immediate bond strength of XPB or CSE adhesive systems (p>0.05), while it improved the bond strength after 1year of aging (p<0.05). Pre-treatment with EDC followed by the application of CSE resulted in an incomplete MMPs inactivation, while EDC pretreatment followed by the application of XPB resulted in an almost complete inactivation of dentinal gelatinases. SignificanceThe μTBS and zymography results support the efficacy of EDC over time and reveal that changes within the dentin matrix promoted by EDC are not adhesive-system-dependent.

Biocompatibility and bond degradation of poly-acrylic acid coated copper iodide-adhesives

ObjectiveTo investigate the effect of poly-acrylic acid (PAA) copper iodide (CuI) adhesives on bond degradation, tensile strength, and biocompatibility. MethodsPAA-CuI particles were incorporated into Optibond XTR, Optibond Solo and XP Bond in 0.1 and 0.5mg/ml. Clearfil SE Protect, an MDPB-containing adhesive, was used as control. The adhesives were applied to human dentin, polymerized and restored with composite in 2mm-increments. Resin–dentin beams (0.9±0.1mm2) were evaluated for micro-tensile bond strength after 24h, 6 months and 1year. Hourglass specimens (10×2×1mm) were evaluated for ultimate tensile strength (UTS). Cell metabolic function of human gingival fibroblast cells exposed to adhesive discs (8×1mm) was assessed with MTT assay. Copper release from adhesive discs (5×1mm) was evaluated with UV–vis spectrophotometer after immersion in 0.9% NaCl for 1, 3, 5, 7, 10, 14, 21 and 30 days. SEM, EDX and XRF were conducted for microstructure characterization. ResultsXTR and Solo did not show degradation when modified with PAA-CuI regardless of the concentration. The UTS for adhesives containing PAA-CuI remained unaltered relative to the controls. The percent viable cells were reduced for Solo 0.5mg/ml and XP 0.1 or 0.5mg/ml PAA-CuI. XP demonstrated the highest ion release. For all groups, the highest release was observed at days 1 and 14. SignificancePAA-CuI particles prevented the bond degradation of XTR and Solo after 1year without an effect on the UTS for any adhesive. Cell viability was affected for some adhesives. A similar pattern of copper release was demonstrated for all adhesives.

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.