Scotchbond Universal Research Articles

Nonthermal Atmospheric Plasma Promotes Bonding Between Adhesive Monomers and Zirconia.

To investigate whether nonthermal atmospheric plasma (NTAP) can promote bonding between commonly used adhesive monomers and zirconia. The zirconia surface and monomers (HEMA, BisGMA, TEGDMA, and MDP) were treated with different NTAP approaches (10 w, 30 s), and the surface characteristics and chemical structures between the zirconia surface and monomers were verified by the contact angle, scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR/FT-IR) spectroscopy, and x-ray photoelectron spectroscopy (XPS). Scotchbond Universal adhesive with two different resin cements, RelyX Ultimate and RelyX Unicem 2, was applied, followed by NTAP-aided clinical procedures, and then microtensile bond strength test (μTBS) and failure mode evaluation were tested for preliminary mechanical properties assessment. One-way ANOVA was employed for the statistical analysis. The contact angle analysis, SEM, and ATR-FTIR confirmed that NTAP can promote the polymerization of BisGMA, TEGDMA, and MDP on the zirconia surface, while XPS confirmed that NTAP can induce a chemical reaction between MDP and zirconia. Nonthermal atmospheric plasma can increase the affinity between selected monomers and zirconia and promote the chemical bonding strength between phosphate monomers and zirconia; besides, it can enhance the bonding strength of two different adhesive systems. The mechanism of how NTAP improved common adhesive monomers interacting with zirconia surfaces was revealed in this study. NTAP, as a relatively high energy-boosting method, could not only improve the surface affinity of zirconia and chemical bonding in-between monomers and zirconia but also enhance the polymerization of different monomers onto zirconia, resulting in improved bonding properties. Thus, further exploration of versatile bonding materials and/or onto different dental substrates could take this into account.

Colloidal platinum nanoparticles enhance resin-dentin bonding durability

ObjectivesThis study aims to investigate the effect of colloidal platinum nanoparticles (CPN) on the durability of resin-dentin bonding performance with contemporary adhesives. MethodsSixty non-carious human maxillary premolars were subjected to microtensile bond strength (µTBS) testing and divided into two main groups: CPN-treated and untreated. Within each group, specimens were randomly allocated to Clearfil Megabond 2 (MB2), Scotchbond Universal Plus Adhesive with self-etch mode (SE-SUP), and etch-and-rinse mode (ER-SUP) subgroups (n = 10/group). CPN was applied to dentin in the MB2 and SE-SUP groups for 20 s, followed by rinsing before adhesive application. In the ER-SUP group, CPN was applied after etch-and-rinse. The µTBS was tested after 24 h, 6 months, and 1 year, and the fracture modes were observed using SEM. The µTBS data were analyzed using a two-way ANOVA and post-hoc Tukey HSD test (α = 0.05). An additional twelve premolars underwent TEM/STEM/EDX for ultra-morphological observations. ResultsThe application of CPN significantly prevented a decline in the µTBS of both the MB2 and SE-SUP groups. No significant decrease was observed in the ER-SUP group, either with aging or CPN application. Ultra-morphological images revealed platinum nanoparticles attaching to the collagen fibrils of the hybrid layer regardless of aging. It was highlighted that the nanoparticles attached to the banded collagen in the aging groups were observed. SignificanceCPN exhibits the potential in enhancing the longevity of resin-dentin bonding in SE mode.

Effect of Silane-Containing Adhesives on Repair Bond Strength between Fresh and Aged Composite Materials-A Pilot Study.

This study investigated the effects of different surface treatments and a silane-containing adhesive on the repair bond strength between fresh and aged resin composites. A total of 140 composite specimens were prepared and aged for 24 h or 4 months. Each group was subdivided into seven subgroups (n = 10) depending on the surface treatment (no surface treatment (NT), sandblasting (SAND), or Sof-lex coarse disc (DISC)) in combination with the use of the silane-containing adhesive ScotchBond Universal Plus (SBU) or an adhesive without silane Prime&Bond Universal (P&B). The same composite was used for the repair as for the primary specimen. Specimens were dark stored in distilled water at 37 °C for 28 days. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. The Kruskal-Wallis test with Bonferroni's post-hoc adjustment (α = 0.05) and the Mann-Whitney U-test were used for the statistical analysis. The results are shown as the median with the interquartile range. The highest bond strength (MPa) was achieved after 24 h in the DISC+P&B (20.39(16.85-28.83)). In the fresh 24 h group, the SAND+P&B (12.25(8.28-15.05)) and DISC+SBU (18.37(15.16-21.29)) were statistically similar. In the 4-month groups, both adhesives and surface treatments performed similarly. The NT, SAND, and DISC groups without adhesives had the lowest bond strength. In the repair of fresh or aged composite, the silane-containing adhesive SBU was not superior to the adhesive without the silane (P&B).

Shear Bond Strength of Orthodontic Brackets to Resin-Infiltrated Enamel

Abstract Objectives This study aims to evaluate shear bond strength (SBS) of orthodontic brackets to enamel after resin infiltration pretreatment using different adhesive systems. Materials and Methods Sixty extracted maxillary first premolars were divided into five groups (n = 12). Group I: sound enamel + Transbond XT; group II: resin-infiltrated enamel (ICON) + Transbond XT; group III: ICON + Scotchbond Universal Plus; group IV: ICON + Assure PLUS; group V: ICON + Transbond Plus Self Etching. The SBS was measured using universal testing machine and analyzed using analysis of variance (ANOVA). The adhesive remnant index (ARI) score after debonding was determined under stereomicroscope with a 10× magnification. Statistical Analysis A one-way ANOVA and post hoc Tukey's test were used to compare the data. Further, the ARI scores were evaluated using a chi-squared test. The level of significance was set at p = 0.05. Results SBS of group I, II, III, IV, and V were 11.70 ± 3.17, 11.23 ± 3.06, 9.52 ± 1.73, 8.97 ± 1.12, and 9.14 ± 0.70 MPa, respectively. SBS of group IV and V was significantly lower than group I and II (p < 0.05). There was no significant difference in the ARI scores among the five groups (p > 0.05). Conclusion The SBS of enamel resin infiltration pretreatment depends on the adhesive system. The SBS of all groups was within adequate SBS range in clinical use. The most common ARI score was 2, which indicated lower risk of enamel fractures when debonding.

Comparative Evaluation of Orthodontic Bonding Systems for Ceramic Brackets on Zirconia Crowns: A Shear Bond Strength and Adhesive Remnant Index Study

Background The purpose of this research was to compare the adhesive residual score/adhesive remnant index (ARI) and shear bond endurance between the two orthodontic bonding systems for zirconia surface bonding: Self-etch (Scotchbond Universal) and total-etch (Transbond XT). Materials and Methods Color-coded acrylic blocks embedded with zirconia slabs were prepared, and the orthodontic brackets (ceramic) were bonded using either the total-etch or self-etch system. Group 1, represented by pink-colored blocks ( N = 12), accommodated 12 zirconia surfaces using the total-etch system, while Group 2, represented purple-colored blocks ( N = 12), also housed zirconia surfaces using the self-etch system. The shear bond strength was evaluated using an Instron Universal Testing Machine, and ARI scoring was done upon debonding. The statistical software SPSS was used for the analyses. Results The average bonding strength for the Scotchbond Universal etch system was 6.21 ± 0.76 MPa, while for the total-etch system, it was 5.59 ± 1.37 MPa. The ARI scores revealed that 83% of surfaces bonded with the self-etch system had no adhesive residue (ARI score 0), compared to 66% for the total-etch system. Conclusion The self-etch bonding agent demonstrated superior bond strength (6.2 MPa) compared to the total-etch system (5.6 MPa). Furthermore, it exhibited better ARI scores, indicating minimal adhesive residue. These findings suggest that the self-etch system is preferable for bonding ceramic brackets to zirconia crowns, offering improved bonding efficacy and ease of clean-up.

Effect of adhesives and mechanical surface treatments on the hard relining of CAD-CAM denture bases.

The aim of this study was to evaluate the impact of mechanical roughening, adhesive applications, and aging on the bonding between CAD-CAM denture base materials with distinct chemical contents and hard relining material. A total of 300 denture base specimens were produced by additive, subtractive, and conventional heat-polymerization techniques (N=100). The specimens have been classified into five subgroups based on the particular surface treatments administered (n=20): (1) Hard relining material's adhesive application (control); (2) Tungsten carbide bur application for 1min, and hard reline material's adhesive application; (3) Airborne-particle abrasion (APA) with 110 μm Al2O3, and hard reline material's adhesive application; (4) Scotchbond Universal application; and (5) Visio.link application. Representative specimens from each subgroup were examined under a Scanning Electron Microscope (SEM). Subsequently, self-cure hard relining material was condensed in the center of the specimens. Half of the specimens were thermally aged with 5000 cycles at 5°C-55°C. The shear bond strength (SBS) test was performed, and failure loads were recorded. The data was evaluated by Robust ANOVA and Bonferroni test (p<0.05). No statistically significant difference was obtained between the production techniques (p = 0.051). The lowest SBS was observed in the control group among surface treatments, while mechanical surface treatments and universal adhesive showed the highest SBS for both aged and non-aged groups. Aging caused a significant decrease for all test groups (p=0.001). Mechanical surface treatments and universal adhesive applications are more effective for maintaining adhesion across all production techniques.

Shelf-life effect of silane-containing universal adhesive on bonding effectiveness to glass-ceramic

ObjectiveTo evaluate the shelf-life effect of a silane-containing universal adhesive (UA) on its shear bond strength (SBS) to lithium disilicate glass-ceramic (LiSi2). MethodsSBS to mirror-polished (‘MP’) and hydrofluoric acid-etched ground (‘HF’) lithium disilicate glass-ceramic (Initial LiSi, GC) with/without prior separate ceramic primer application (G-Multi Primer, GC: ‘G-MP’) was measured. Scotchbond Universal Plus (‘SBUp’) (3M Oral Care) was used 33 (‘fresh’) and 6 (‘expiring’) months before the expiration date. ‘MP’ specimen preparation involved (1) ‘G-MP’ priming (or not), (2) ‘SBUp’ application, (3) composite (Clearfil AP-X, Kuraray Noritake) placement, and (4) 20 s light-curing (SmartLite Pro, Dentsply Sirona). ‘HF’ specimen preparation involved (1) HF (Porcelain Etch, Ultradent) etching, (2) phosphoric acid (K-Etchant, Kuraray Noritake) post-etching, with (3) and (4) being the same as for ‘MP’. Upon light-curing, all specimens were stored in 37 °C water for either 1 week (‘immediate’) or 3 months (‘aged’) prior to SBS measurement. Statistics involved Linear Mixed-Effects modelling (α = 0.05). ResultsSBS was not significantly affected by SBUp's shelf life, except for a significantly higher SBS recorded for ‘fresh’ SBUp applied on HF-etched and separately silane-primed LiSi2. Aging did not significantly decrease SBS. In fact, a significant increase in SBS upon aging was recorded for HF-etched LiSi2 that was not separately silane-primed. The significantly highest bond strength was measured when LiSi2 was HF-etched followed by separate silane-priming. SignificanceDespite the UA investigated has silane in its formulation, the most effective and durable bonding to LiSi2 was achieved by HF-etching followed by separate silane-priming, irrespective of the UA's shelf life.

Do in vitro and in situ erosive challenges alter the bonding performance of universal adhesives?

ObjectiveTo evaluate microtensile bond strengths (μTBS), nanoleakage (NL), and degree of conversion (DC) of two universal adhesives, using etch-and-rinse (ER) or self-etch (SE) strategies on eroded dentin submitted to in vitro and in situ erosive challenges. MethodsDentin blocks were prepared from 120 human molars and categorized based on dentin condition (sound, in vitro eroded, and in situ eroded), adhesive system (Scotchbond Universal [SBU] and Zip bond Universal [ZIP]), and adhesive strategy (ER and SE). In the in situ erosive challenge, 20 volunteers wore acrylic resin palatal devices with dentin blocks, immersing them in cola soft drink for 90 s, six times daily for 15 days. The same erosive protocol was used in vitro, followed by rinsing and remineralization. Sound dentin blocks served as controls. Afterward, all dentin blocks were restored with composite resin and sectioned into resin-dentin bonded sticks for μTBS, NL, and DC assessments. Data were analyzed using three-way ANOVA and Tukey's test (α = 0.05). ResultsSound dentin exhibited the highest μTBS and DC values and the lowest NL values, while in situ eroded dentin showed the lowest μTBS and DC values and the highest NL values (p = 0.000001). While some differences in the μTBS values were observed between universal adhesives when evaluated on sound dentin (p = 0.0001), no significant differences between adhesives were observed when tested on in vitro and in situ eroded dentin. Regarding NL and DC, no significant differences were found between SBU and ZIP, as well as among adhesive strategies (p > 0.05). ConclusionErosion in dentin, especially under in situ conditions, presents significant challenges to the adhesion of restorative materials. The choice of an effective adhesive system is crucial, as dentin eroded in situ showed lower adhesion strength and greater nanoleakage. These results highlight the need for specific clinical strategies to improve the durability and effectiveness of restorations.

Clinical evaluation of a new chemically-cured bulk-fill composite in posterior restorations: 6-month multicenter double-blind randomized clinical trial

ObjectiveTo evaluate the postoperative sensitivity (POS), as well as the clinical performance of posterior restorations using a new chemically-cured bulk-fill composite (Stela Automix and Stela Capsule, SDI) comparing with a light-cured bulk-fill composite after 6 months. MethodsFifty-five participants with at least three posterior teeth needing restoration were recruited. A total of 165 restorations were performed on Class I or Class II cavities. After the application of Stela primer, the chemically-cured composite (Stela Automix or Stela Capsule) was inserted. For the light-cured composite group, a universal adhesive (Scotchbond Universal) was applied with a bulk-fill composite (Filtek One). Participants were evaluated for spontaneous and stimulated POS in the baseline, after 48 h, 7 days, and 6 months. Additionally, each restoration was assessed using the updated version of FDI criteria after 6 months. The differences in the proportions of the groups were compared by Cochran test statistics (α = 0.05). ResultsBoth chemically-cured composites showed a lower risk of POS compared to the light-cured composite at baseline and up to 48 h (p < 0.04). A significantly lower surface luster and texture was observed for the Stela Capsule composite compared to the light-cured bulk-fill composite (baseline and 6 months; p = 0.03). A significant color mismatch was observed for the light-cured bulk-fill composite compared to the chemically-cured composites (baseline and 6 months; p = 0.03). No significant differences were observed in any other item evaluations (p > 0.05). ConclusionChemically-cured composites exhibit lower postoperative sensitivity and less color mismatch compared to a light-cured bulk-fill composite after 6 months of clinical service. Clinical significanceThe chemically-cured composites appear to be an appealing option for restoring posterior teeth, as they exhibit lower postoperative sensitivity compared to a light-cured bulk-fill composite, both at baseline and up to 48 h, and less color mismatch.

Is additional silane application necessary for a new silane-containing universal adhesive to bond to glass ceramics?

To evaluate the in vitro influence of prior silane application on the microshear bond strength (μSBS) of Scotchbond Universal Plus to glass ceramic. Thirty blocks of lithium disilicate ceramic were etched with hydrofluoric acid for 20 s and distributed into Group 1 (no silane and no adhesive), Group 2 (adhesive), Group 3 (silane + adhesive). Three cylinders of resin cement were made on each ceramic block. Five blocks (n = 15 cylinders) were subjected to the μSBS test after 24 h, and the other five blocks (n = 15 cylinders) were tested after 6 months of water storage. According to two-way ANOVA, followed by Tukey's test, the means of μSBS (MPa), denoted by different letters, show significant differences (p < 0.05): after 24 h-Group 1 (31.7)B, Group 2 (43.3)A, and Group 3 (31.3)B; after 6 months-Group 1 (14.8)B, Group 2 (33.6)A, and Group 3 (30.3)A. After 6 months of storage, there was a significant decrease in μSBS for Groups 1 and 2, along with an increase in adhesive failures across all groups. Prior application of silane did not increase the μSBS between Scotchbond Universal Plus and ceramic, and there was degradation at the bond interface over time. Prior application of a silane agent is not necessary when using Scotchbond Universal Plus for bonding to glass ceramics. Regardless of the prior application of silane, there is degradation at the bond interface over time.

Effects of the application protocol and bonding strategy of the universal adhesive on dentin previously impregnated with bioceramic sealer

PurposeTo evaluate the effects of the application of universal adhesive with manual brush (MB) or rotary brush (RB), in the etch-and-rinse (ER) or self-etching (SE) strategy, on the bond strength, adhesive layer thickness, and adhesive failure pattern to dentin impregnated with bioceramic sealer, at 24 h and 1 year. Materials and methodsEighty-eight bovine incisor crowns were impregnated with bioceramic sealer was kept for 15 min and cleaned with cotton soaked in distilled water. They were then divided into four groups (n = 22): ER-MB, ER-RB, SE-MB, SE-RB. Subsequently, the specimens were restored with Filtek Z-250 resin. The adhesive layer thickness was individually analyzed using laser confocal microscope. Bond strength was assessed through microtensile testing, and the failure pattern was examined using a stereomicroscope. Data were analyzed by one-way ANOVA/Tukey's tests (α = 0.05). ResultsThe adhesive layer thickness provided by ER-MB and SE-MB was greater than that provided by ER-RB and SE-RB (P < 0.05). ER-MB showed the lowest bond strength at 24 h (P < 0.05). At 1 year, SE-MB and SE-RB exhibited the highest bond strength values (P < 0.05). ER-MB demonstrated a higher incidence of adhesive failure at 24 h. At 1 year, SE-RB and SE-MB showed a higher incidence of mixed failure. ConclusionThe use of Scotchbond Universal® adhesive in the etch-and-rinse strategy applied with a MB negatively affects bond strength at 24 h, worsening after 1 year of control, regardless of the application protocol.

Effect of multi-layer applications of self-etch universal bonding agents on the adhesion of resin composite to enamel.

To evaluate the effect of adhesive coats application on the enamel microtensile bond strength (µTBS) of universal adhesives, morphological etching pattern and their chemical interaction with hydroxyapatite (HA). Two universal adhesives were investigated: Scotchbond Universal (SBU, 3M) and Prime&Bond Universal (PBU, Dentsply). The adhesives were applied in self-etching mode on bovine enamel (n = 8) in one (1L), two (2L) or three coats (3L) and light-cured as per manufacturers' instructions. As controls adhesives were applied to etched enamel (H3PO4-37% phosphoric acid). Bonded specimens were cut into sticks that were stored in deionized water for 24h or 6months prior to µTBS testing. Two-way ANOVA and Tukey's test were used for statistical analysis of bond strength with α = 5%. For morphological SEM analysis, enamel surfaces were treated as aforementioned and immediately rinsed with acetone. The intensity of monomer-calcium salt formation from each treatment was measured via infrared spectroscopy (ATR-FTIR). All treatments presented no significant reduction on µTBS after aging (p > 0.05). However, SBU attained highest µTBS when applied in 3L. PBU showed higher µTBS when applied to H3PO4 etched enamel than 1L or 2L. Etching pattern was enhanced by 3L application, particularly with PBU. Chemical interaction was notably higher for SBU than PBU, with no relevant differences with more layers or prior H3PO4-etching. The application of three adhesive coats of universal adhesives in self-etch mode using may enhance the bonding performance and etching pattern to enamel, surpassing the H3PO4-etched enamel bond for SBU. The chemical interaction with calcium from enamel is not affected by number of coats or prior phosphoric acid etching.

Effects of Endodontic Irrigants on Shear Bond Strength of Mild Universal Adhesives to Dentin

PurposeThe objective of this in vitro study was to evaluate the shear bond strength (SBS) of several universal adhesives to dentin treated with sodium hypochlorite (NaOCl), and NaOCl followed by ethylenediaminetetraacetic acid (EDTA). Materials and MethodsAdhese Universal, Scotchbond Universal, Prime & Bond Elect, Prime & Bond Active, and Optibond XTR were included in the study. SBS values were determined in self-etch mode with no pretreatment of the dentin, after a 20-minute exposure of the dentin to 6% NaOCl, and after a 20-minute exposure to NaOCl followed by a one-minute exposure to 17% EDTA. Experimental groups were repeated using a total-etch technique (except Optibond XTR). ResultsAdhesives in self-etch mode had significantly reduced SBS following dentin exposure to NaOCl (P < .05), while with a total-etch technique, only Prime & Bond Active was affected (P < .05). SBS in self-etch mode when NaOCl exposure was followed by EDTA were equal to or higher than negative control values (P < .05). For total-etch groups, Adhese Universal was negatively affected by NaOCl + EDTA exposure (P < .05). Prime & Bond Elect exhibited lower SBS following NaOCl + EDTA exposure when compared to just NaOCl exposure but was not different from the negative control (P < .05). ConclusionFor the adhesives tested, the use of 17% EDTA following NaOCl exposure negated the negative effects of NaOCl on SBS in self-etch mode. When used in total-etch mode, results varied significantly, with some adhesives performing better or worse depending on the specific testing condition.

Effect of Instrument Lubricant on Mechanical Properties of Restorative Composite.

Using a wetting resin or adhesive system as an instrument lubricant when placing composite layers is commonly practiced to improve handling. This study investigated whether instrument lubricants affected strength, stiffness, or hardness. Composite beams (TPH Spectra) were fabricated using a stainless steel mold (25×2.5×2 mm) in two steps, where the second half (12.5 mm) was added and cured against a cured first half (n=15). The composite surface at the open end of the first half was smoothed using an instrument lubricated with wetting resin (Ultradent) or universal adhesive (ScotchBond Universal), enough to prevent sticking, or without lubrication. An additional beam of each group was characterized using scanning electron microscopy. Monolithic specimens were also fabricated. After 24 hour storage (37°C, 100% humidity), the beams' flexural strength and stiffness were determined by four-point bending. Vickers surface hardness was measured on 24-hour composite samples in 2 mm deep acrylic cavities, cured after the surface was smoothed with the two instrument lubricants or no lubricant (n=10). Hardness was remeasured after finishing with a series of contouring and polishing discs. Data were statistically analyzed using ANOVA followed by Student-Newman-Keuls post hoc test at 0.05 significance level. There were significant differences (p<0.001) in flexural strength and stiffness among groups. While strength and stiffness were not affected by using a wetting resin as instrument lubricant, use of a universal adhesive increased strength and stiffness significantly, achieving monolithic values. Scanning electron micrographs showed less porosities at the interface when using instrument lubricants. Surface hardness was significantly reduced in groups in which instrument lubricants were used, but finishing/polishing restored original hardness (p<0.001). Lubricating an instrument with a wetting agent did not adversely affect physical or surface properties, provided the surface was finished and polished. If a universal adhesive was used as lubricant, the strength and stiffness of a layered composite could be increased, reaching monolithic values.

Effect of trialkoxysilane/aminosilane-containing universal adhesive on resin-ceramic microtensile bond strength and ceramic wettability: An in-vitro study

BackgroundThe dual-silane (trialkoxysilane/aminosilane) universal adhesive (UA) is claimed for its enhanced priming capacity of glass-ceramics. ObjectiveThis study evaluated the effect of organofunctional trialkoxysilane- and organofunctional trialkoxysilane/aminosilane-containing UAs on the long-term resin–ceramic microtensile bond strength (μTBS) and wettability of ceramic. MethodsHydrofluoric acid-etched lithium disilicate discs were distributed into four groups as follows: (control), no priming was performed; (MBN), primed using a silane-based primer (Monobond N); (SBU), primed using a trialkoxysilane-containing UA (Single Bond Universal Adhesive) and (SBP), primed using a trialkoxysilane/aminosilane-containing UA (Scotchbond Universal Plus Adhesive). Ceramic discs were cemented into blocks then sectioned into microbeams stored in distilled water at 37° for 1 year. The μTBS was evaluated followed by assessment of the failure modes. The contact angle of the two UAs was measured with a goniometer using the sessile drop technique. ResultsMBN significantly improved the resin-ceramic μTBS (31.71 ± 6.33 MPa) compared to the control group. The resin-ceramic μTBS obtained after priming using SBP (22.83 ± 3.42 MPa) was comparable to those of MBN. SBU showed significantly inferior resin-ceramic μTBS (16.02 ± 6.28 MPa) compared with MBN. Mixed failures mode patterns were the most frequent in the groups. The ceramic wettability of both UAs did not significantly differ. ConclusionCeramic priming using a UA with dual-silane monomers (organofunctional trialkoxysilane/aminosilane) resulted in long-term adhesion comparable to a silane-containing primer. Incorporating aminosilane monomer in UA formulation did not affect the wetting of characteristics of the UA solution and enhanced its glass-ceramic priming capacity. Clinical significanceThe use of UA with optimized silane content as a primer for glass-ceramics simplifies clinical adhesive procedures including resin cementation and repair of ceramic restorations.

Effect of different surface treatments on the repair bond strength between aged and new alkasite based restorative material.

This study investigates various surface treatment methods to assess shear bond strength between set Cention N (alkasite-based restorative material) and new alkasite based restorative material. Assessing different surface treatments provide insights in optimizing repair procedure that enables durability of the restoration, thus potentially benefitting clinical outcomes. A total of 48 alkasite based restorative material blocks, measuring 4 mm in depth and 4 mm in diameter, were prepared. The samples were randomly divided into 8 groups (n = 6) according to the surface treatment done. Group I: Surface preparation by bur; Group II: Surface treatment by laser; Group III: Application of 2-step etch and rinse adhesive (Adper Single Bond 2 adhesive),Group IV: Application of single step self-etch adhesive (Scotchbond Universal adhesive); Group V: Bur preparation followed by application of 2-step etch and rinse adhesive; Group VI: Bur preparation followed by application of single step self-etch adhesive; Group VII: Laser preparation followed by application of 2-step etch and rinse adhesive; and Group VIII: Laser preparation followed by application of single step self-etch adhesive. Post-surface preparation, all the specimens were restored with newly mixed alkasite material. Repair bond strength measurements were assessed with universal testing machine. Shapiro-Wilk and Levene's tests were used to check normality and Homogeneity of variance. ANOVA with post-hoc Games-Howell test and two-way ANOVA with post-hoc Bonferroni test was performed to evaluate the influence of surface preparation on the repair bond strength. Using a 2-step etch and rinse adhesive resulted in a higher repair bond strength (26.05±2.12) compared to other surface treatments. In contrast, roughening of the surface with burs led to lowest repair bond strength (17.06±3.29) (P=0.02). Application of 2-step etch and rinse adhesive to the existing alkasite based restorative material provides superior bonding with the newly added alkasite based restorative material.

The effect of combining primers and cements from different cement systems on the bond strength between zirconia and dentin

ObjectiveThe aim of this study was to evaluate the influence of combining primers and cements from two different resin cement systems on the microtensile bond strength (μTBS) between zirconia and human dentin.Materials and methodsA total of 120 specimens of zirconia cemented to dentin were allocated into eight groups based on cement type (RelyX Ultimate or Panavia V5) and primers (Tooth Primer, Clearfil Ceramic Primer and Scotchbond Universal Adhesive) combinations, applied to dentin or ceramic surfaces. Following artificial aging with 5000 thermocycles, μTBS tests were conducted. Statistical analysis was performed using One-way ANOVA and Tukey’s post hoc tests (p ≤ 0.05), and failure modes were assessed.ResultsThe Panavia V5 cement system demonstrated the highest bond strength (19.4 ± 4.4 MPa), significantly higher than the other groups except when RelyX cement was used with Panavia primers (16.9 ± 3.7 MPa). Cohesive fractures within the cement layer were the predominant failure mode.ConclusionsThe combination of primers from different adhesive cement system brands may significantly affect the bonding effectiveness. Therefore, using products from a single product line of the same adhesive cement system, and following the manufacturer’s recommendations for indications and use, is crucial for a more predictable clinical outcome.

Influence of residues from bioceramic sealer on the bond interface with universal adhesive in different application modes.

This study evaluated the effect on adhesive layer thickness, bond strength, and adhesive failure pattern of the application of universal adhesive (Scotchbond Universal) using either manual or rotary brush in dentin previously impregnated with bioceramic sealer (Sealer Plus BC) using a manual brush, at 24h and 1 year. Eighty-eight bovine crowns were divided into four groups (n=22) according to the intervention: (i) use of bioceramic sealer and adhesive application using manual brush, (ii) use of bioceramic sealer and adhesive application using rotary brush, (iii) use of resin sealer and adhesive application using manual brush, and (iv) use of resin sealer and adhesive application using rotary brush. Subsequently, specimens were restored with a composite resin (Filtek Z-250). Adhesive layer thickness was evaluated using confocal microscopy. Bond strength was assessed using the microtensile bond strength test, and adhesive failure pattern was evaluated under a stereomicroscope. Data were analyzed using two-way ANOVA/Tukey tests. Specimens where a rotary brush had been used exhibited lower adhesive layer thickness. Specimens treated with resin sealer and using a manual brush showed lower bond strength values and a higher occurrence of adhesive failures at 24h and 1 year than specimens treated with bioceramic sealer and using rotary brush for adhesive application.

One-Year Evaluation of High-Power Rapid Curing on Dentin Bond Strength.

This study investigated the effect of 3 s light-curing with a high-power LED curing unit on the shear bond strength of bulk-fill composites. Four bulk-fill composites were bonded to dentin with a universal adhesive (Scotchbond Universal Plus): two materials designed for rapid curing (Tetric PowerFill and Tetric PowerFlow) and two controls (Filtek One Bulk Fill Restorative and SDR Plus Bulk Fill Flowable). The 4 mm composite layer was light-cured with Bluephase PowerCure for 20 s at 1000 mW/cm2 ("20 s") or for 3 s at 3000 mW/cm2 ("3 s"). The samples were stored at 37 °C in distilled water and tested after 1, 6 and 12 months. The samples polymerised in the "3 s" mode had statistically similar or higher bond strength than the samples cured in "20 s" mode, except for the Tetric PowerFlow (1 month) and SDR+ (6 month). The flowable materials Tetric PowerFlow and SDR Plus initially showed the highest values in the "3 s" and "20 s" groups, which decreased after 12 months. The bond strength was statistically similar for all materials and curing protocols after 12 months, except for Tetric PowerFill cured with the "3 s" protocol (21.22 ± 5.0 MPa), which showed the highest value. Tetric PowerFill showed the highest long-term bond strength. While "3 s" curing resulted in equal or better shear bond strength, its use can only be recommended for a material with an AFCT agent such as Tetric PowerFill.

Sealing of pulp chamber dentin in endodontics: Influence of bond strategy and time-point application

Context: Seal the dentin of the pulp chamber during endodontic treatment to avoid interfering with the restorative treatment performed afterward. Aims: The aim was to evaluate the effect of three adhesive systems applied in different bonding strategies (etch-and-rinse, self-etch, and universal adhesive) and time-point application (immediately after the cavity access preparation or after endodontic obturation) on the hybrid layer formation and dentinal penetrability. Materials and Methods: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used and the time-point application: Adper Scotchbond Multi-purpose (AS), Clearfil SE (CF) and Scotchbond Universal (SU) in strategy of immediate endodontic sealing (IES) or delayed endodontic sealing (DES). In IES-AS, IES-CF, and IES-SU groups, dentin sealing was performed immediately after the cavity access, while in DES-AS, DES-CF, and DES-SU, after root canal obturation. The specimens were sectioned in the long axis, in a buccal-lingual direction, and the dentinal penetrability of the adhesive systems was evaluated using confocal microscopy images. Hybrid layer formation was analyzed by scanning electron microscopy images. Statistical Analysis Used: Dentinal penetrability data were analyzed with the ANOVA test and the Kruskal–Wallis test was performed for hybrid layer data (α = 0.05). Results: IES-CF showed the lowest dentinal penetrability (P &lt; 0.05), while the other protocols were similar to each other (P &gt; 0.05). No significant differences were found between groups regarding the hybrid layer formation (P &gt; 0.05). Immediate and DES protocols do not influence the hybrid layer formation, regardless of the bond strategy used. Conclusions: Sealing the pulp chamber dentin before endodontic treatment can improve the bond strength of the final restoration but the formation of the hybrid layer was not influenced by the bond strategy.