Year Of Water Storage Research Articles

Does the Application of Additional Hydrophobic Resin to Universal Adhesives Increase Bonding Longevity of Eroded Dentin?

This paper evaluates the effect of an additional hydrophobic resin coat (extra HL) associated with universal adhesives on sound and eroded dentin and evaluated immediately or after 2 years of water storage to improve the microtensile bond strength (μTBS) and nanoleakage (NL) when compared to the use of universal adhesives only. Sixty-four molars were assigned to eight groups using the following combinations: 1. dentin substrate, including sound and eroded dentin; 2. treatment, including the control and extra HL and storage time (immediately and after two-years of storage). Two universal adhesives (Prime & Bond Active or Scotchbond Universal) were evaluated. Before restoration, half of the teeth were subjected to soft-drink erosion. Composite buildups were bonded; specimens were stored (37 °C/24 h), sectioned into resin–dentin bonded sticks and tested for microtensile bond strength and nanoleakage using SEM (immediately and after two-years of storage). Three-way ANOVA and Tukey’s test (α = 0.05%) were used. In the immediate testing, the application of extra HL did not increase microtensile bond strength values compared with the control group in either substrate (p > 0.05). However, extra HL significantly decreased nanoleakage values when applied to eroded and sound dentin (p = 0.0001). After two years, the application of extra HL produced significantly higher microtensile bond strength and lower nanoleakage values than the control group for both adhesives (p = 0.0001). In all cases, sound dentin showed higher microtensile bond strength and lower nanoleakage values than eroded dentin (p = 0.000001). An extra HL increased the bond strength and reduced nanoleakage in eroded dentin after two-years of storage.

Effect of airborne particle abrasion and primer application on the surface wettability and bond strength of resin cements to translucent zirconia

The purpose of this study was to evaluate the effect of sandblasting and primer application on the immediate and long-term shear bond strength of resin cements to translucent zirconia. Zirconia plates (Katana STML, Kuraray Noritake Dental) were divided into six groups (n = 10) for shear bond strength evaluation using three resin cements (Panavia V5, Kuraray Noritake Dental; Variolink Esthetic LC, Ivoclar-Vivadent; and Panavia SA Cement Universal, Kuraray Noritake Dental). The zirconia was sandblasted or left unabraded. Each cement was used with the indicated primer. Two cylinders of cement were placed on the zirconia, one for evaluation after 24 h and the other after 1 year of storage in water. The fracture pattern and the contact angle were observed on all groups. At 24 h, there were no differences in bond strength of the cements for equal sandblasting conditions. After 1-year, the bond strength of all groups decreased, except for Panavia V5 associated with sandblasting. For all the cements, the unabraded zirconia showed a lower bond strength and a higher rate of adhesive failures. The application of primers reduced the contact angle. Higher bond strength is obtained when primers are combined with sandblasting using aluminum oxide particles. Clinical significance: Translucent zirconia restorations should be treated by airborne particle abrasion and phosphate-based primers before bonding, to improve the wettability of the cements and obtain a more durable bonding between the cement and the zirconia.

An in-vitro investigation of the bond strength of experimental ion-releasing dental adhesives to caries-affected dentine after 1 year of water storage

ObjectiveThe aim of this study was to evaluate the bonding performance after 1 year storage of an experimental dental adhesive containing analogues of phosphoproteins and fluoride-doped bioglass (EXP), applied in self-etching (SE) or etch & rinse (ER) mode, to caries-affected dentine after selective caries removal. Materials and MethodsFifty human molars with dentine carious lesions were excavated selectively using CarisolvTM gel and then connected to simulated pulpal pressure system. Teeth were divided randomly into five groups based on the tested materials: EXP-SE, EXP-ER, a resin-modified glass-ionomer cement (RMGIC), a three-step adhesive system (OPT) and a universal adhesive applied in SE mode (UA-SE). The specimens were submitted to different analytical tests (μTBS, SEM fractographic analysis and dye-enhanced confocal microscopy) at baseline (T0) and after 1 year (T1). ResultsAt T0 there was no difference in bond strength between the tested materials (p>0.05). At T1, EXP-SE and EXP-ER were the only materials to show no significant reduction in bond strength (p<0.05). The SEM showed a clear presence of minerals deposited on the dentine surface after bonding in the EXP-SE and EXP-ER groups. The specimens restored with RMGIC showed no exposure of the dentine surface after failure. The OPT and UA-SE specimens showed clear signs of degradation at the interface. Confocal microscopy imaged mineral precipitation at the interface of the EXP groups. ConclusionConventional adhesives may have inadequate bonding performance with evident degradation at the dentine-bonded interface over time. Although the RMGIC may present a drop in bond strength after prolonged storage, the bonding interface may result less affected by degradation over time. Innovative ion-releasing adhesives may remineralise the caries-affected dentine and achieve a stable bond over time. Clinical significanceGIC-based materials may represent an appropriate dentine replacement material after selective chemo-mechanical caries removal rather than conventional adhesive systems.

Effect of Argon Plasma Surface Treatment on Repair of Resin Composite Aged Two Years.

To evaluate the effect of argon plasma treatment (PLA) when combined with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) on the shear bond strength (SBS) of a two-year water-aged resin composite bonded to a newly placed composite after 24 hours and one year of water-storage. Thirty-six light-cured composite plates (20mm x 20mm x 4mm thick) were obtained and stored at 37°C in distilled water for 2 years. These aged plates were distributed into 6 groups (n=6) according to the surface treatment: no treatment (Negative Control); SAN+SIL+HBR (Positive Control); SAN+PLA+SIL+HBR; PLA+ SIL+HBR; PLA+SIL; PLA+HBR. Fresh resin composite cylinders were built up using silicone molds (hole: 1.5 mm high x 1.5 mm diameter) positioned over the aged plates. Half of the SBS samples were stored in distilled water for 24 hours and loaded until failure, while the other half were stored for 1 year before being tested. Data were submitted to two-way analysis of variance and post-hoc Tukey Test (preset alpha of 0.05). Positive Control, SAN+PLA+SIL+HBR and PLA+SIL+HBR groups presented higher SBS means at the 24 hour evaluation. After 1 year of water storage, all groups demonstrated significant SBS reduction, with the SAN+PLA+SIL+HBR group presenting the highest SBS. Resin plasma treatment in combination with other surface treatments can improve the SBS of composite repairs after one year of water storage. The SBS of the composite repair was not stable over time regardless of the surface treatment.

72 - Six-Year Bond Stability of Universal Adhesives with Alternative Dentin Treatments

Evaluate the effects of four dentin treatments on microtensile bond strength (MBS) for two universal adhesives, ScotchBond Universal (SBU) and All-Bond Universal (ABU), after 24-hour, 1-year and 6-year water storage. Flat dentin surfaces from human molars were treated as follows: (i) phosphoric acid 35% (PA) for 15 s; (ii) PA for 5 s; (iii) 17% EDTA for 60 s; (iv) no treatment (self-etch mode). One of the two universal adhesives was then applied to the surface. After 24-hour storage at 37 C, teeth were sectioned to obtain beams (~0.9mm2) and randomly assigned to one of the storage times (24 h, 1-y and 6-y). Specimens were tested until failure at 1.0 mm/min on each incubation period. Failure modes were assessed with light microscope at 40x (Olympus, Tokyo, Japan). Data was submitted to Three-Way ANOVA and all pairwise multiple comparison (Holm-Sidak) at significance level = 0.05. Statistical differences were detected for surface treatments and storage times. A significant interaction between adhesive and treatment was found (p<0.01). The bond strengths were affected by the different surface treatments, depending on the adhesive, except for 17% EDTA with similar results for both systems. After 6-year storage, SBU showed more stable MTBS with 17% EDTA 32.36 (14.09) and self-etch mode 30.10 (13.80) (p<0.05). For ABU, the lowest MTBS was observed with the self-etch mode for all storage times (p<0.01). However, 17% EDTA treatment for ABU at 6-year storage 39.85 (21.03) exhibited the highest MTBS (p<0.01). Overall, 17% EDTA treatment showed a positive effect on dentin bonding stability. The self-etch mode showed better performance for SBU compared to ABU. The failure modes for all groups were predominantly adhesive and mixed. The dentin bonding stability with universal adhesives depends on the surface treatment for each adhesive material. The use of 17% EDTA for 60 s to treat dentin prior to the application of universal adhesives could be considered an alternative approach to improve bond durability.

Evaluation of Novel Plant-derived Monomers-based Pretreatment on Bonding to Sound and Caries-affected Dentin.

This study evaluated the influence of new monomers derived from cashew nut shell liquid (CNSL) applied for dentin biomodification on resin-dentin bond strength, nanoleakage, and micropermeability to sound and artificially-created caries-affected dentin. Human dentin specimens were assigned to five groups, according to the following dentin pretreatment solutions: Absolute ethanol (control), 2 wt% grape seed extract (Vitis vinifera), 2 wt% cardol [from cashew nut shell liquid (CNSL)], 2 wt% cardol-methacrylate or 2 wt% cardanol-methacrylate applied on sound and artificial caries-affected dentin. Specimens were analyzed after 24 hour or 1 year of water storage. Microtensile bond strength (μTBS) (n=6), interface micropermeability (n=3), and silver nanoleakage (n=6) were assessed using a universal testing machine, confocal laser scanning microscope, and scanning electron microscope, respectively. In sound dentin, no difference in bond strength was observed between the groups in either storage period. In artificial caries-affected dentin, pretreatment with cardol-methacrylate resulted in statistically higher bond strength than all the other treatments in both storage periods. Cardol-methacrylate treatment resulted in less nanoleakage, along with improved interfacial integrity, compared to further treatments in artificial caries-affected dentin. Regarding micropermeability analysis, all treatments depicted deficient sealing ability when applied on artificial caries-affected dentin, with the presence of gaps in the control group. In conclusion, cardol-methacrylate is a promising plant-derived monomer to reinforce the hybrid layer, since it preserved resin-dentin bond strength and improved dentin bonding, especially to caries-affected dentin, a well-known harsh substrate for adhesion longevity.

Nanofiller Particles and Bonding Durability, Water Sorption, and Solubility of Universal Adhesives

The aim of this study was to evaluate the influence of nanofiller particles in simplified universal adhesive on the long-term microtensile bond strength and silver nitrate up-take, as well as water sorption and solubility. Commercial adhesives Ambar Universal (FGM) in nanofilled-containing version (filled) and same lot without fillers (unfilled) were donated and applied by means of etch-and-rinse strategy. Microtensile bond strength was surveyed after 24-hours or 1-year water storage. Silver nitrate uptake was assayed using scanning electron microscopy (SEM). Water sorption and solubility experiments were performed based on ISO 4049:2009. Statistical analysis was performed using two-way ANOVA and Tukey test (p<0.05). The bond strength of both the adhesives were statistically similar at 24 hours (p>0.05), but the filled group attained significant bond strength reduction after aging when compared to initial bond strength (p<0.001). Conversely, unfilled adhesive presented stable adhesion after 1-year storage (p=0.262). Silver nitrate uptake was similar for both adhesives, with little silver impregnation at the hybrid and adhesive layers. Water sorption was higher with filled adhesive compared to the unfilled one (p=0.01). Conversely, solubility was higher in unfilled in comparison to filled one (p=0.008). The presence of nanofillers in universal adhesive achieves higher water sorption and dentin bond degradation, which did not occur in the unfilled adhesive.

Effect of universal adhesive application on bond strength of four-year aged composite repair

Introduction Universal adhesives were introduced to provide faster adhesive application and a less technique-sensitive procedure, however, there is a dearth of studies in the literature about the use of Universal adhesives in composite repair techniques. Objective To evaluate the effect of universal adhesives systems on the shear bond strength (SBS) of fresh composite to four-year water-aged composite, simulating resin composite repair technique, after 24 h and one year of water storage. Material and Methods Thirty-six composite (Charisma, Kulzer) plates were fabricated and stored in distilled water at 37 °C for 4 years. The aged plates were sandblasted and assigned to the groups (n = 9): SMP: Silane (Ceramic Primer, 3 M Oral Care) + Adper Scotchbond Multi-Purpose Adhesive (3 M Oral Care – control); GBU: Gluma Bond Universal (Kulzer); ADU: Adhese Universal (Ivoclar Vivadent); SBU: Scotchbond Bond Universal (3 M Oral Care). Two fresh composites (Charisma, Kulzer) cylinders were constructed on each plate with the same composite and tested after 24 h or 1 year of water storage, using the MSBS testing. Data were analyzed by ANOVA and Tukey test (a = 0.05). Results At 24-hour evaluation time, there was no statistical difference among the bonding repair strategies. After one year of water storage, GBU exhibited the lowest bond strength outcome, while the other groups did not differ among them. Control, ADU, and SBU kept the bond strength values stable until one year. Conclusions The combination of sandblasting and ADU and SBU Universal adhesives presented the same outcome observed for the control and stable bond strength after 12-months of water storage.

Eight-year Microtensile Bond Strength to Dentin and Interfacial Nanomechanical Properties of a One-step Adhesive.

To evaluate the microtensile bond strength (µTBS) of a one-step self-etch adhesive (1-SEA) to dentin and its interfacial nanomechanical properties after 8 years of water storage. Flat coronal dentin surfaces of extracted human third molars were bonded with a 1-SEA (Clearfil S3 Bond Plus, CS3+) and built up with a hybrid resin composite (Clearfil AP-X). After storage in water for 24 h or 8 years, non-trimmed stick-shaped specimens were fabricated from the central part of each bonded tooth and subjected to the µTBS test at a crosshead speed of 1.0 mm/min. Failure modes and the morphology of debonded interfaces were analyzed using a scanning electron microscope (SEM). In addition, the elastic modulus (E) and hardness (H) of the adhesive layer and the resin composite were determined by an instrumented nanoindentation test. The acquired µTBS, E, and H data were statistically analyzed using t-tests to examine the effect of storage time (α = 0.05). The 8-year µTBS was slightly lower than that after 24 h, but the difference was not significant (p = 0.123). The SEM observation of debonded surfaces after 8 years revealed extrusions and lacunas. E and H of the adhesive layer and the resin composite significantly decreased over the 8-year water storage (p < 0.001). Although 8 years of water storage did not decrease the µTBS of CS3+ significantly, the observed failure mode patterns and significantly decreased nanomechanical properties indicated resin degradation of the adhesive and the resin composite.

Resin bond strength to translucent zirconia: A 2-year follow-up

The aim of this study is to evaluate the effect of aging on resin bond strength to translucent zirconia treated with the most clinically used bonding procedures. Monolithic translucent zirconia-based ceramic (3Y-TZP) blocks were surface treated using airborne-particle abrasion with alumina particles (AP) or silica-coated alumina particles (SC) then bonded to resin composite blocks using a resin cement system containing a silane coupling agent and an adhesive with a phosphate (MDP) monomer. Bar-shaped specimens (bonding area: 1 mm 2 ) were fabricated (n = 30) and stored in 37 °C distilled water for the following time before testing: 7 days (SCI and API); 1 year (SC1 and AP1); and 2 years (SC2 and AP2). Specimens were loaded to failure under tension using an Instron testing machine. Microtensile bond strength (σ f ) data was statistically analyzed using Weibull distribution, analysis of variance (ANOVA) and Tukey tests (α = 0.05). Failures were evaluated using fractographic principles. Mean σ f values significantly decreased after 2 years of water storage (SC2 and AP2) (p < 0.05), although there was no difference in the Weibull modulus. All specimens failed cohesively within the adhesion zone at the zirconia-cement adhesive interface.

Self-etch Approach of Universal Adhesives as an Alternative to Minimize Bond Degradation on Sound Dentin vs Caries-affected Dentin over Time.

To investigate the influence of the etching strategy of universal adhesives on bond degradation to sound and artificially-induced caries-affected dentin. The universal adhesives (Scotchbond Universal Adhesive; All-Bond Universal; Prime&Bond Elect) and adhesives used as controls (Adper Single Bond 2 and Clearfil SE Bond) were applied to sound and artificially-induced caries-affected bovine dentin. Microtensile bond strength was evaluated immediately (24 h) and after one year of water storage (1 year). Representative specimens were also prepared to assess nanoleakage. Bond strength data (MPa) were analyzed using three-way ANOVA and post-hoc Tukey's test (α = 0.05), considering each substrate separately. Bonding degradation was observed for all universal adhesives on caries-affected dentin, irrespective of the etching strategy. On sound dentin, bonding degradation was observed when adhesives were used on the etch-and-rinse strategy. The universal adhesives were not capable of maintaining bond stability over time on caries-affected dentin. The self-etch strategy seems better able to maintain the durability of adhesive interfaces created on sound dentin.

Effect of argon plasma on repair bond strength using nanofilled and microhybrid composites.

To evaluate the effect of atmospheric pressure plasma (PLA), sandblasting (SAN), silanization (SIL) and hydrophobic bonding resin (HBR) on the micro-shear bond strength (MSBS) of fresh nanofilled (NF) or microhybrid (MH) composites to water-aged nanofilled composite. NF plates were fabricated and stored in distilled water for 4 months. The aged plates were assigned to the groups (n=6): 1- untreated; 2- SAN + SIL + HBR; 3- HBR; 4- PLA + HBR; 5- SAN + HBR; 6- SAN + PLA + HBR; and 7- PLA. Two fresh composite cylinders were constructed on each plate with NF or MH composites and tested after 24 h or 1year of water-storage, using the MSBS testing. Data were analyzed by three-way ANOVA and Tukey test (α=0.05). NF yielded better outcomes than MH at 24 h, which was not observed at 1 year. HBR showed the highest MSBS results, while untreated and PLA groups yielded the lowest one. MSBS reduced for all groups after 1 year. Only HBR can obtain good MSBS results, while PLA alone was not beneficial. After 1 year, a reduction in repair MSBS was observed and the type of composite did not influence the results. The repair technique can be simplified with the use of only an adhesive and macromechanical retentions in the old composite, regardless the type of fresh composite.

Effect of Addition of Dimethyl Sulfoxide to Simplified Adhesives on Dentin Bond Durability after Three Years of Water Storage.

To evaluate the effect of inclusion of two dimethyl sulfoxide (DMSO) concentrations in simplified etch-and-rinse adhesives on dentin bonding durability after three years of water storage. Forty-two caries-free third molars were divided into six experimental groups (n = 7) according to the following factors: 1) adhesive (Adper Single Bond 2 [SB], 3M Oral Care; Prime&Bond 2.1 [PB], Dentsply Sirona); 2) concentration of DMSO (control group: 0.0% DMSO; addition of 0.2% DMSO [0.2] and 2% DMSO [2.0]). After completing restoration, specimens were stored in water (37°C) for 24 h, sectioned into adhesive-dentin sticks (0.8 mm2), tested for microtensile bond strength (µTBS) at 0.5 mm/min, and examined for nanoleakage (NL) using SEM immediately thereafter or after three years of water storage. Data were subjected to a three-way repeated-measures ANOVA and Tukey's test (α = 0.05) for each property evaluated. After three years of water storage, for both adhesives, the incorporation of 2% DMSO maintained the µTBS when compared to immediate µTBS (p > 0.05). In general, SB resulted in a statistically significantly higher mean of µTBS compared to PB, independent of the DMSO concentration after water storage (p < 0.05). Furthermore, the amount of NL was lower and practically limited to the hybrid layer given the concentrations of 0.2% and 2% DMSO for both tested adhesives after three years. The incorporation of DMSO in simplified etch-and-rinse adhesives maintains the long-term stability of the dentin bond.

Effects of Sandblasting and Hydrofluoric Acid Etching on Surface Topography, Flexural Strength, Modulus and Bond Strength of Composite Cement to Ceramics.

To evaluate the influence of different surface treatments of two CAD/CAM glass ceramics on surface topography, shear bond strength of composite cement, flexural strength, and elastic modulus. Two ceramics were evaluated: lithium-disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) glass ceramics. Glass ceramics were sintered and the surfaces were sandblasted (SBL) or etched with 9% hydrofluoric acid for 10 s (HF10), 20 s (HF20) or 30 s (HF30). The treated surfaces were analyzed using scanning electron microscopy (n = 3) to evaluate the etching pattern. For bond strength testing, ceramic samples were silanized after treatments and an adhesive was applied to the surface. Afterwards, a silicone mold was used to build composite-cement cylinders, which were tested after 24 h or one year of water storage (n = 10). Flexural strength and modulus were assessed using a 3-point bending test (n = 15). The data were subjected to statistical analysis at a pre-set α = 0.05. SBL and HF resulted in different surface topographies. Increased HF etching time influenced the surface dissolution level and exposition of crystals for LDS, while no effect of etching time was observed for ZLS. After one year, the bond strength to LDS significantly decreased, regardless of treatments. For ZLS, HF10 and HF20 showed stable bond strengths over time. SBL yielded the lowest bond strength for both ceramics and statistically significantly reduced the flexural strength of ZLS. The flexural strength and elastic modulus of ceramics were not affected by different etching times. Bonding stability depended on the glass ceramic and the pretreatment method employed. HF etching did not change the mechanical properties of the ceramics and is indicated as a ceramic treatment for bonding.

Durability of bond strength to dentin using two universal adhesives in different etching modes

Aim. To evaluate the bond durability of two universal adhesives; mild and ultra-mild in both etch-and-rinse and self-etch modes after simulated in-vitro degradation by long-term water storage or thermocycling. Methods. A total of 144 specimens were used in this study; 120 specimens (prepared from 30 teeth) for microshear bond strength testing and fracture mode assessment, and 24 specimens for scanning electron microscopic evaluation (prepared from 24 teeth). Specimens were prepared from 54 recently extracted caries free third molars and randomly divided into 12 groups, according to the adhesive treatment (All Bond or Scotchbond Universal), etching mode (etch-andrinse or self-etch) and aging method (thermocycling or water storage). Each tooth was sectioned mesio-distally into two halves exposing free dentin surface for bonding where dentin substrate 1 mm below the dentino-enamel junction was used. After adhesive application and composite build up, specimens were tested in shear mode after storing in distilled water at 37˚C for 24 hours or 1 year, or after being thermocycled between 5 and 55 °C for 10,000 cycles (n=10). Microshear bond strength (μSBS) was tested using a universal testing machine. Adhesive-dentin interface was examined using scanning electron microscope (SEM) (n=2). Data were analyzed using 3 way AN0VA and pairwise comparisons was performed using Bonferroni correction at significance level of α ≤0.05. Results. Statistical analysis revealed non-significant difference for etching mode in both adhesives (p=0.596). After aging, the bond strength was only reduced in Scotchbond Universal after one year of water storage in both modes (p&lt;0.001). SEM evaluation revealed intact hybrid layer and longer resin tags for etch-and-rinse mode than selfetch mode of both adhesives. Conclusion. The bond strength of universal adhesives is not affected by the etching mode, however its durability was shown to be material dependent.

Adhesion of Resin Cement to Zirconia Using Argon Plasma and Primer.

To evaluate the effectiveness of nonthermal atmospheric plasma (NTAP) and priming on the shear bond strength (SBS) of a resin cement to two zirconia ceramics after 24 hours and 1 year of water storage. A total of 120 plates (9 x 7 x 2 mm) were obtained from two types of zirconia (Katana, Kuraray Noritake; and ZirCAD, Ivoclar Vivadent) plates randomly divided into 12 groups (n = 10 each). Zirconia ceramic plates were submitted to the following treatments: (1) untreated (control); (2) treated with ZPrime Plus (Bisco Dental) primer; (3) NTAP (Surface Plasma Tool Model SAP, Surface Engineering and Plasma Solution) application for 10 seconds; (4) NTAP for 30 seconds; (5) NTAP for 10 seconds followed by priming; and (6) NTAP for 30 seconds followed by priming. Two silicone molds (2.37-mm diameter x 2-mm height) were positioned on the treated surface of each zirconia plate, and the resin cement (Panavia F 2.0, Kuraray Noritake) was manipulated and inserted into the molds. After light activation, two resin cement cylinders (specimens) were obtained from each plate. One specimen was tested after 24 hours, and the other after 1 year. The shear load was applied to the base of the resin cement cylinders until failure. Data were analyzed using three-way ANOVA and post hoc Tukey test (α = .05). NTAP application alone (groups 3 and 4) increased SBS compared to the control group only at 24 hours. After 1 year, the NTAP/primer combination showed higher SBS than the other groups. Water storage for 1 year reduced the bond strength for all groups. NTAP, combined or not combined with primer, had a beneficial effect on adhesion after 24 hours and after 1 year. Water storage negatively influenced the adhesion in all groups.

Influence of Silane Pretreatment and Warm Air-Drying on Long-Term Composite Adaptation to Lithium Disilicate Ceramic

Background: Repair bonding to lithium disilicate ceramic (LDS) remains an issue. This study examined whether the adaptation of a resin composite to LDS can be improved by a silane pretreatment and warm air-drying. Methods: LDS blocks (IPS e.max CAD) with prefabricated tapered cavities were bonded using a silane-containing universal adhesive (Clearfil Universal Bond Quick ER; UBQ) or the bonding agent of a two-step self-etch adhesive (Clearfil SE Bond 2), with and without a silane pretreatment (Clearfil Ceramic Primer; CP). CP and the adhesives were air-dried with normal air (23 ± 1 °C) or warm air (60 ± 5 °C), light-cured, and the cavities were filled with a flowable composite. Interfacial gap formation was evaluated using swept-source optical coherence tomography immediately after filling, after 24 h, 5000 and 10,000 thermal cycles, and an additional 1 year of water storage. Results: Without the silane pretreatment, all specimens soon detached from the cavities. Warm air-drying significantly decreased gap formation compared to normal air-dried groups (p &lt; 0.001) and improved long-term stability (p &lt; 0.001). The lowest gap formation was observed with UBQ when the silane pretreatment was combined with warm air-drying. Conclusions: Composite adaptation to LDS was insufficient without silanization, but it was stable in the long term if the silane pretreatment and warm air-drying were combined.

Incorporation of Apigenin and tt-Farnesol into dental composites to modulate the Streptococcus mutans virulence

ObjectivesThe aim of this in vitro study was to incorporate two anti-caries agents, Apigenin and tt-Farnesol, to resin composite and resin cement to reduce the virulence of Streptococcus mutans around dental restorations. MethodsApigenin (Api, 5 mM) and tt-Farnesol (Far, 5 mM) were added alone, together, and combined with fluoride (F). Biofilm of S. mutans was grown on composite discs, and the dry-weight, bacterial viability, and the polysaccharides (alkali-soluble, intracellular and water-soluble) were quantified. CLSM images of the S. mutans biofilm were obtained after three years of water-storage. The effect of the additions on the physicochemical properties and the composite colorimetric parameters were also analyzed. ResultsThe additions did not affect bacterial viability. Api alone and combined with Far or combined with Far and F decreased the bacterial dry-weight, alkali-soluble and intracellular polysaccharides. After three years, the composites containing the additions presented a greater EPS matrix on the top of biofilm. Statistical difference was obtained for the degree of conversion; however, the maximum polymerization rate and curing kinetics were unaffected by the additions. No difference was observed for the water-soluble polysaccharides, flexural strength, and elastic modulus. Api increased the yellowness of the composites. SignificanceApi, alone and combined, reduced the expression of virulence of S. mutans without jeopardizing the physicochemical properties of the composites.

Class II resin composite restorations\u2014tunnel vs. box-only in vitro and in vivo

PurposeIn a combined in vitro/in vivo approach, tunnel vs. box-only resin composite restorations should be evaluated using thermomechanical loading (TML) in vitro and a restrospective clinical trial in vivo.Materials and methodsFor the in vitro part, box-only and tunnel cavities were prepared in 32 extracted human third molars under simulated intraoral conditions in a phantom head. Specimens were randomly assigned to four groups (n = 8; 16 box-only/16 tunnel) and received bonded resin composite restorations with Amelogen Plus (box A/tunnel A) or lining with Ultraseal and Amelogen plus (box B/tunnel B) both bonded using PQ1 (all Ultradent). Specimens were subjected to a standardized aging protocol, 1-year water storage (WS) followed by TML (100,000 × 50 N; 2500 × + 5/+ 55 °C). Initially and after aging, marginal qualities were evaluated using replicas at × 200 magnification (SEM). For the corresponding in vivo observational study, 229 patients received 673 proximal resin composite restorations. From 371 tunnel restorations, 205 cavities were filled without flowable lining (tunnel A), and 166 tunnels were restored using UltraSeal as lining (tunnel B). A total of 302 teeth received conventional box-only fillings. Restorations were examined according to modified USPHS criteria during routine recalls up to 5 years of clinical service.ResultsIn vitro, all initial results showed 100% gap-free margins when a flowable lining was used. Tunnels without lining exhibited some proximal shortcomings already before TML and even more pronounced after TML (p < 0.05). After TML, percentages of gap-free margins dropped to 87–90% in enamel with lining and 70–79% without lining (p < 0.05). In vivo, annual failure rates for box-only were 2.2%, for tunnel A 6.1%, and for tunnel B 1.8%, respectively (p < 0.05). Tunnels had significantly more sufficient proximal contact points than box-only restorations (p < 0.05). Flowable lining was highly beneficial for clinical outcome of tunnel-restorations (p < 0.05).ConclusionsWith a flowable lining, tunnel restorations proved to be a good alternative to box-only resin composite restorations.Clinical relevanceClass II tunnel restorations showed to be a viable alternative for box-only restorations, however, only when flowable resin composite was used as adaptation promotor for areas being difficult to access.

Long-term evaluation of warm-air treatment effect on adaptation of silane-containing universal adhesives to lithium disilicate ceramic.

The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).