FiltekTM Supreme XTE Research Articles

An in vitro evaluation of the fatigue behavior of resin composite materials as part of a translational research cycle

PurposeThis study aimed to reproduce and translate clinical presentations in an in vitro set-up and evaluate laboratory outcomes of mechanical properties (flexural strength, fatigue resistance, wear resistance) and link them to the clinical outcomes of the employed materials in the Radboud Tooth Wear Project (RTWP). Materials and methodsFour dental resin composites were selected. 30 discs (Ø12.0 mm, 1.2 mm thick) were fabricated for each of Clearfil TM AP-X (AP), Filtek TM Supreme XTE (FS), Estenia TM C&B (ES), and Lava Ultimate (LU). Cyclic loading (200 N, 2 Hz frequency) was applied concentrically to 15 specimens per group with a spherical steatite indenter (r = 3.18 mm) in water in a contact-load-slide-liftoff motion (105 cycles). The wear scar was analysed using profilometry and the volume loss was digitally computed. Finally, all specimens were loaded (fatigued specimens with their worn surface loaded in tension) until fracture in a biaxial flexure apparatus. The differences in volume loss and flexural strength were determined using regression analysis. ResultsCompared to AP and FS, ES and LU showed a significantly lower volume loss (p < 0.05). Non-fatigued ES specimens had a similar flexural strength compared to nonfatigued AP, while non-fatigued FS and LU specimens had a lower flexural strength (p < 0.001; 95 %CI: −80.0 – 51.8). The fatigue test resulted in a significant decrease of the flexural strength of ES specimens, only (p < 0.001; 95 %CI: −96.1 – −54.6). Clinical relevanceThese outcomes concur with the outcomes of clinical studies on the longevity of these composites in patients with tooth wear. Therefore, the employed laboratory test seems to have the potential to test materials in a clinically relevant way.

Surface Roughness Evaluation of Resin Composites after Finishing and Polishing Using 3D-Profilometry

The purpose of this study was to evaluate the effect of two finishing and polishing methods on the surface roughness of different resin composites. Twenty-two disk-shaped specimens of five resin composites Zirconfill® (ZF), Filtek™ Supreme XTE (FS), Brilliant EverGlow™ (BG), Ceram.X® Duo (CD), and Harmonize™ (HA) were prepared for each one using a silicon mold. Both surfaces of each specimen were first grinded with 600-grit silicon carbide paper in a moistened environment. The polishing methods used included the two-step Enhance® and PoGo® polishing system (E/P) or the four-step SwissFlex® discs (SFD). Surface roughness was evaluated using a noncontact 3D-optical profilometer. Surface morphology was examined by scanning electron microscopy. Data were analyzed using two-way analysis of variance and pairwise comparisons with Tukey’s test ( α = 0.050 ). Surface roughness was affected by both the type of resin composite ( p &lt; 0.001 ) and the finishing and polishing system ( p &lt; 0.001 ), with a significant interaction between these two factors ( p = 0.025 ). The E/P system produced smoother surfaces than the SFD system ( p &lt; 0.001 ). For the E/P system, the highest mean roughness value was obtained with ZF and was statistically different from all other composites, whereas inhomogeneous results among resin composites could be found for the SFD system. Surface roughness was material-dependent, and the polishability of the resin composites was best accomplished using the E/P system. Within each F/P system studied, BG showed the lowest average surface roughness and ZF registered the highest.

Effect of dental composite dust on human gingival keratinocytes.

The aim was to investigate the effect of particles released during grinding of dental composites on human gingival keratinocytes (HGK). Specimens from Filtek™ Supreme XTE and ceram.x® universal were prepared and ground to dust. The dust was filtered (≤ 5µm) and the particle size distribution was examined using NANO-flex®-180° dynamic light scattering (DLS). Suspensions at five concentrations (3, 10, 30, 100 and 300µg/mL) were prepared using keratinocyte growth medium (KGM). These suspensions, as well as a positive (CuO) and a negative control (KGM) were added to HGK. The cells treated with Filtek™ Supreme XTE suspensions were analyzed by real-time monitoring using RTCA iCELLigence™. In addition, light and scanning electron microscopic images of the exposed cells were taken. Indirect immunofluorescence staining was performed to detect the extracellular matrix protein fibronectin. In distilled water, DLS showed similar particles' range (171.9nm- 2.7µm) for both composites. In saliva, larger particles were detected (Filtek™ Supreme XTE: 243nm-6,5µm; ceram.x® universal: 204nm- 4,6µm). iCELLigence™ revealed similar results of cell growth parameters for HGK incubated with composite dust (≤ 5µm) at different concentrations. The microscopic images indicated unaltered cell structures and formation of large agglomerates with high particle concentration (> 100µg/mL). Exposure to composite dust resulted in upregulation of fibronectin expression. Grinding of dental composite materials generates dust particles of different sizes. The particle size distribution seems to be more influenced by the suspending medium than the material itself. While cell growth of HGK seem not to be affected by the particles, an upregulation of fibronectin in the intercellular space concomitant by increasing particle concentration may indicate an increase of cell migration/mobility.

Method development for the intraoral release of nanoparticles from dental restorative materials.

The aim of this study was the development of a novel in-vitro method to evaluate the intraoral release of wear particles with a diameter<1µm from dental restorative materials. Test fixtures for a dual-axis chewing simulator (CS-4.8, SD Mechatronik, Feldkirchen-Westerham, Germany), consisting of three components to mount the specimens and a solvent (distilled water) as well as a zirconia antagonist to transfer the masticatory forces onto the specimen was developed. Ceram.x Spectra™ ST HV (CS) and Filtek™ Supreme XTE (FS) specimens (n=3) were fixed into the mounts and immersed in 25ml solvent. All specimens were subjected to 500.000 wear cycles with a load of 49N. The particle size distribution of the suspensions were examined by dynamic light scattering (DLS). The collected particles were characterised by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). For wear quantification, the surfaces of the specimens were photo-optically scanned and the wear was measured. For the statistical analysis, one-way ANOVA and post-hoc Scheffétests were applied. DLS showed particle diameters<1µm (CS: 18.06nm-1.64µm, FS: 72.30nm-2.31µm). SEM/EDS indicated an association between the detected elements and the materials' composition. FS showed significantly higher volume loss (p=0.007) and maximum depth of the wear profile (p=0.005) than CS, but no significant differences in the surface loss (p=0.668). The novel method is able to detect material dependent particles to the size of nanoscale after in-vitro abrasion.

Cytotoxic and inflammatory response of human lung epithelial cells A549 to particles released from dental restorative materials during dry and wet grinding.

The aim was to evaluate the release of particles from dental materials during wet and dry grinding and test their effects on human lung epithelia cells in-vitro. Four dental restorative materials were used: two composites [Ceram.x® universal (Dentsply Sirona) and Filtek™ Supreme XTE (3M)], one ceramic [VITABLOCS® Mark II (VITAy)] and a ceramic-resin material [Lava™ Ultimate (3M)]. Material samples were ground to powder under standardized wet and dry conditions in an isolated dental room. During grinding, the particle concentrations were measured with LAS and CPC. Baseline values were measured before grinding. The particles' size was evaluated using DLS and SEM. Water was used as control. The cytotoxicity and inflammatory response of the lung cells (A549) after exposure to different concentrations (1, 3, 10, 30, 100, 300μg/mL) of the generated dust were analyzed with LDH, WST-1 and ELISA. LAS and CPC revealed a high concentration of particles<10µm and<1µm respectively, into the air. Particles showed high tendency to agglomerate. DLS showed particle size distribution between 150nm and 18µm independently of the material composition. All materials induced significant effects (p<0.05) on the cell membrane integrity and viability of the A549 cells. Only the ceramic particles showed a significant increase in hydroxyl radical formation at low concentrations (p<0.05), for both wet and dry conditions. All materials except ceramic, induced a significant release of IL-8 in A549 cells at 300μg / mL (p<0.05). Wet and dry grinding of dental materials result in release of ultrafine and fine particulate matter into the air. The in-vitro findings on the cellular response of lung cells to generated dust indicate a potential risk for human health due inhalation of the released particles. The use of water-cooling seems to be beneficial resulting in reduced release of particles compared to dry grinding.

Clinical Outcomes and Quantitative Margin Analysis of a Universal Adhesive Using a Randomized Clinical Trial over Three Years.

The effectiveness of a universal adhesive applied in different application modes for the preparation of Class V composite restorations was evaluated both clinically and by quantitative marginal analysis (QMA). In each of the 22 patients, four non-carious cervical lesions (NCCL) were restored with Filtek™ Supreme XTE (3M). The adhesive Scotchbond™ Universal (SBU, 3M) was applied in self-etch (SE), selective-enamel-etch (SEE) or etch-and-rinse (ER) modes. The etch-and-rinse adhesive OptiBond™ FL (OFL, Kerr) served as a control. The restorations were clinically evaluated (FDI criteria) after 14 days (BL), 6, 12, 24, and 36 months. Additionally, QMA was conducted on all restorations of 11 randomly selected patients. The FDI criteria and marginal gap were statistically compared between the groups at each recall as well as for the time periods between recalls. The cumulative failure rate was non-significantly higher in the OFL group when compared to all of the SBU groups. Marginal adaptation in the OFL and SBU-SE/ER groups was significantly decreased (BL-36 m, p: 0.004) in comparison to the SBU-SEE group (BL-36 m, p: 0.063). More marginal gaps were found in the OFL group than in the SBU-SEE (BL to 36 m, p: 0.063-0.003) and SBU-ER (24/36 m, p: 0.066/0.005) groups as well as in the SBU-SE group when compared to the SBU-SEE (12-36 m, pi ≤ 0.016) and SBU-ER (24/36 m, p: 0.055/0.001) groups. SBU-SEE performed most effectively. The clinical evaluation and QMA corresponded, yet QMA detected group differences earliest after 6 months and is thus a valuable extension to clinical evaluations.

Clinical evaluation of bulk-fill and universal nanocomposites in class II cavities: Five-year results of a randomized clinical split-mouth trial

AimEvaluating the clinical survival and quality parameters of class-II restorations using 3M™ FiltekTM Bulk Fill Posterior Restorative compared to 3M™ FiltekTM Supreme XTE Universal Restorative over a period of five years. Materials and methodsA longitudinal, randomized, prospective split-mouth study with 60 patients (29 female, 31 male; mean age 44 y; range 20-77 y) and a total of 120 load-bearing class II restorations (TEST: n=60 Filtek Bulk Fill Posterior Restorative; CONTROL: n=60 Filtek Supreme XTE Universal Restorative) was conducted. Clinical evaluation was performed by blinded evaluators according to FDI criteria. Kaplan-Meier method was used for survival analysis and an intergroup comparison (Mann-Whitney-U-Test) was carried out. A basic significance level of 0.05 was corrected by the Bonferroni method to account for multiple testing (significance after correction: p<0.00067). ResultsThe mean overall survival of restorations was 92% after 56.98±1.51 months in the TEST group (95 CI= 54.02;59.94) and 92% after 57.25±1.46 months (95 CI= 54.39; 60.12) in the CONTROL group (log-rank p=0.995). In total, four failures occurred in both TEST and CONTROL group during the observation period (mean annual failure rate: 1.6%). The most common reasons for failure were chipping-fractures, debonding, cracked-tooth-syndrome and recurrent decay. With regard to the FDI criteria, no significant differences between TEST and CONTROL material occurred for any of the evaluated variables. In the TEST group two restorations had to be repaired and two had to be replaced, in the CONTROL group four restorations had to be replaced. ConclusionBoth materials showed acceptable clinical performance and survival during the 5-year observation period. Clinical SignificanceThe use of a nanofilled bulk-fill composite proved to be an aesthetically, functionally and biologically satisfactory alternative in posterior dentition.

A randomized clinical split-mouth trial of a bulk-fill and a nanohybrid composite restorative in class II cavities: Three-year results

ObjectivesThe aim of this randomized controlled clinical trial was to evaluate the clinical survival and quality parameters of class-II restorations using a bulk-fill composite resin compared to a conventional nanohybrid composite resin in a split-mouth design. MethodsOne hundred and twenty direct restorations were placed in stress bearing class II cavities (n = 60 test group: Filtek™ Bulk Fill Posterior and n = 60 control group: Filtek™ Supreme XTE) in adult permanent teeth. Survival and clinical quality were evaluated at baseline and after 3 years using modified World Dental Federation (FDI) criteria. Participants and clinical evaluators were blinded relating to the group assignment of the restorations. ResultsSeventeen restorations (14.2%) were lost to follow-up, leading to 51 restorations available for survival analysis in the test group and 52 restorations in the control group. Seven restorations showed unfavorable events and were classified as failure. Four bulk-fill restorations failed due to tooth infracture (n = 1), chipping fractures (n = 2) and recurrent decay (n = 1), whereas three conventional nanohybrid composite restorations failed due to adhesive failure (n = 1), tooth infracture (n = 1) and chipping as well as recurrent decay (n = 1). The mean annual failure rate was 2.4% and 1.8%, respectively. The difference between test and control group was not significant (p = 0.7). Data on the detailed assessment of FDI criteria were available for n = 48 and n = 49 restorations, respectively. No significant differences between the two groups could be found regarding the assessment of esthetic, functional and biological properties. SignificanceBoth materials showed similar clinical performance and survival. The use of bulk-fill composite proved to be an esthetically, functionally and biologically satisfactory alternative in the posterior dentition during the 3-year follow-up.

Microbial contamination of resin composites inside their dispensers: An increased risk of cross-infection?

ObjectivesTo evaluate the effects of microorganisms’ contamination inside the dispensing syringes of different types of resin-based composites (RBCs). MethodsThis study encompassed two sections. First, an anonymous electronic survey was submitted via Google forms to Italian dentists to acquire information about composite handling during clinical procedures. Then, a bench test was performed on nanohybrid RBCs differing in matrix chemistry and fillers [FiltekTM Supreme XTE (3MTM); Venus Pearl (Kulzer GmbH); Admira Fusion x-tra (Voco)] to evaluate the microbial viability on their surfaces with/out photocuring. Uncured RBCs were exposed to standardized inocula of Streptococcus Mutans, Candida Albicans, Lactobacillus Rhamnosus, or mixt plaque in an in vitro model reproducing clinical restorative procedures. Half of the RBC specimens were cured after exposure. Microbial viability was assessed using an MTT-based test. Statistical analysis included three-way ANOVA and Tukey's tests (p<0.05). ResultsAmong 300 dentists completing the survey, the majority declared to use the spatula to carry the RBCs from the syringe to the dental cavity (50% same spatula; 35% two spatulas). However, 80% of respondents had personal feelings that using one spatula could be a source of cross-contamination. In vitro results using one spatula showed microbial contamination of all RBCs after one hour of storage. The contamination levels depended on the used strain and RBC type (p<0.0001), but photocuring did not reduce contamination (p = 0.2992). ConclusionsMicrobial species’ viability on uncured RBCs and after photocuring shows the existence of a considerable risk of cross-infection. Clinical procedures in Restorative Dentistry need to acknowledge and to reduce such risk during RBCs handling. Clinical significanceDentists must be aware of the possibility of cross-infection during restorative procedures, especially when the same spatula is repeatedly used for placing RBC in the cavity.

Cytotoxicity and estrogenicity in simulated dental wastewater after grinding of resin-based materials

ObjectiveThis study evaluated the cytotoxic and estrogenic effects of dust and eluates released into simulated wastewater after grinding of dental resin-based materials. MethodsFour materials were used: ceram.x® universal, Filtek™ Supreme XTE, Lava™ Ultimate and Core-X™ flow. From each composite material, samples (5 × 2 mm, n = 50) were prepared according to the manufacturers’ instructions. Lava™ Ultimate was used as blocks. All samples were ground to dust with a diamond bur (106 μm) and suspended in distilled water at 60 mg/mL. After storage for 72 h, the suspensions were separated into a soluble (eluate) and a particulate (dust) fraction. Eluates and dusts were evaluated for inhibition of Vibrio fischeri bioluminescence and cytotoxicity on human A549 lung cells (WST-1-Assay). The estrogenic activity was assessed by YES-Assay using Saccharomyces cerevisiae. Additionally, dental monomers (BisGMA, BisEMA, UDMA, TEGDMA, HEMA) and Bisphenol A were investigated. ResultsAll eluates showed inhibition of V. fischeri bioluminescence at concentrations above 1.1 mg/mL (p < 0.05). The activity of the eluates of ceram.x® universal and Filtek™ Supreme XTE was significantly higher than Lava™ Ultimate and Core-X™ flow (p < 0.05). In the WST-1-Assay, all materials induced cytotoxic effects at concentrations of 0.1 mg/mL (p < 0.05), while no significant differences were detected among them. The tested materials revealed no estrogenic activity. All dental monomers and Bisphenol A showed concentration dependent cytotoxic effects (p < 0.05), whereas only Bisphenol A induced an estrogenic effect (p < 0.01). SignificanceDust and eluates of resin-based dental materials released into wastewater exert bactericidal and cytotoxic effects in vitro. However, they reveal no estrogenic effect.

Fracture toughness of dental incremental composite-composite interfaces at elevated temperatures

The aim of the present laboratory study was to mechanically characterize the interface between two dental resin-based composite (RBC) increments, and to investigate if elevated temperatures have an influence on the quality of the interface mimicking clinical filling procedure. Four RBCs (CLEARFIL MAJESTY™ Posterior, Kuraray (CMP)/Filtek™ Supreme XTE, 3M (FSX)/Grandio®SO, VOCO (GSO)/VisCalor® bulk, VOCO (VCB)) were tested with a fracture toughness test using Chevron notched beams (KI,CNB) at 23, 37 and 54 °C. KI,CNB specimens (3 × 4x25mm) with a V-shaped notch at the incremental interface were loaded until failure in a 4-point bending set-up. Failure modes were characterized using light microscopy, microstructural interface was analyzed using SEM. Statistical analysis was performed using Kolmogorov-Smirnoff test, two-way ANOVA and Tukey Post-Hoc test (p = 0.05). Mean KI,CNB ranged between 0.73 ±0.14 MPam0.5 (VCB, 23 °C) and 1.11 ± 0.11 MPam0.5 (FSX, 23 °C). The tested conventional highly filled RBCs presented fracture toughness at the incremental interface comparable to the cohesive strength of the bulk materials. VCB showed reduced interfacial fracture toughness at 23 and 37 °C, but performed well at elevated temperature of 54 °C.

Vital pulp therapy in a 9-years-old patient: a clinical case

Introduction Dental trauma is a public health problem, that have a complex aetiology, with a negative impact in the people life [1]. It has been reported that 25.7% of the children visit a dentist for the first time due to emergency situations. The most frequently reported injury seems to be damage to the enamel or the dental crowns in children [2]. Approximately 31% of dental injuries are caused by sporting activities, and many of these traumas can be prevented [3,4]. The anterosuperior teeth are, in most cases, the most injured, affecting the patient’s self-esteem. This study aims to present a clinical case of a definitive tooth that suffered a crown fracture with a pulp exposure. Materials and methods A 9-year-old male was referred to paediatric dentistry clinic, with the chief complaint “Treat the tooth that fractured about one hour ago in the school” SIC mother. A detailed medical, dental, and social history was obtained, a clinical analysis was performed, confirming the crown trauma with a pulp exposure, positive pulpal vitality tests in the upper left incisor, without apical lesion in the radiological analysis, after signed informed consent the treatment first stage consisted in vital pulp therapy, that was performed with partial pulpotomy wherein the sealing material was MTA-Angelus®. In the second stage it was done a direct restoration with rubber dam technique and a silicone index using the Filtek™ Supreme XTE universal dental composite. Results After the treatment and 2 years of follow-up the tooth presented satisfactory aesthetic and functional results and this treatment increased the patient's self-esteem. Discussion and conclusions In the present case the vital pulp therapy was performed once the tooth had complete root formation and had signs and symptoms of a pulp exposure without apical lesion. MTA has been shown to be a great pulpotomy agent its sealing ability, biocompatibility and regeneration of the original tissues when placed in contact with dental pulp tissue [5]. It is crucial to develop educational programs that emphasise the importance of prevention and the benefits of immediate treatment. Adequate diagnosis, planning and follow-up of treatment are important to get favourable results and to increase in the patient's self-esteem [6].

N-Acetylcysteine modulates the effects of composites on human gingival keratinocytes

ObjectiveThe aim of this study was to evaluate, if antioxidants, like N-Acetylcysteine, can modulate effects of composite eluates on human gingival keratinocytes. MethodsComposite samples of ceram.x® universal, Filtek™ Supreme XTE, and Admira® Fusion were stored 72h in cell culture medium to prepare eluates, according to ISO 10993-12:2012. Human gingival keratinocytes were exposed to these eluates with or without 3mM N-Acetylcysteine. Following cell observation by iCELLigence®, exposure periods were determined at 1d and 4d. Cell morphological analysis combined with live/dead staining was performed. Tissue-specific biomarkers of terminal differentiation, Involucrin and Filaggrin, were analyzed by indirect immunofluorescence (IIF) and Western blot (WB). qPCR profiling was performed on genes encoding for: inflammation, apoptosis, turn-over of extracellular matrix, adhesion, proliferation and differentiation. For statistical analysis one-way Anova was used (p<0.05). ResultsCells exposed to N-Acetylcysteine exhibited morphological changes but no cell death. After adding 3mM N-Acetylcysteine to HGK cultures, increased fluorescence intensity and protein amounts of Involucrin and Filaggrin indicated enhanced differentiation (p<0.05). Gene expression was modulated by: (i) composition of the composite eluates, (ii) NAC and (iii) exposure time. Filtek™ Supreme XTE showed a significant increased gene expression in inflammatory genes (p<0.05), which was amplified by the addition of NAC at 1d. Concerning exposure time, modulated gene expression showed eluate dependency, substantiated by Filtek™ Supreme XTE modulation at day 1 and Admira® Fusion at day 4. SignificanceN-Acetylcysteine-emerging effects on gingival keratinocytes were threefold: (i) increase of differentiation, (ii) modulation of composite-related effects and (iii) in parts counteraction of eluate-induced effects.

Evaluation of degree of conversion, rate of cure, microhardness, depth of cure, and contraction stress of new nanohybrid composites containing pre-polymerized spherical filler.

The aim of the present study was to characterize nanohybrid and nanofilled composites in terms of degree of conversion (DC), rate of cure (RC), microhardness (Vickers hardness number; VHN), depth of cure, and contraction stress (CS). Ceram.X® universal- A3, duo enamel E2, and duo dentin D3 composites were compared to Tetric EvoCeram® and FiltekTMSupreme XTE composites of equivalent dentin and enamel shades under a 40 s photopolymerization protocol. DC was measured by infrared spectroscopy, calculating RC from the kinetic curve. Top and bottom VHN were determined using a Vickers indenter, and bottom/top surface ratio (Vickers hardness ratio; VHR) calculated. CS vs. time was assessed by a universal testing machine and normalized for the specimen bonding area. All materials showed DC < 60%, Ceram.X® composites reaching higher values than the other composites of corresponding shades. RC at 5 s of photopolymerization was always higher than that at 10 s. All the Ceram.X® composites and the lighter-shaded Tetric EvoCeram® and FiltekTMSupreme XTE composites reached the RC plateau after 25 s, the remaining materials showed a slower kinetic trend. Tetric EvoCeram® and FiltekTMSupreme XTE composites displayed the softest and the hardest surfaces, respectively. Differently from darker-shaded materials, the universal and the three enamel-shaded composites resulted optimally cured (VHR > 80%). The tested composites differed in CS both during and after light cure, Tetric EvoCeram® and FiltekTMSupreme XTE composites displaying the highest and the lowest CS, respectively. Only the Ceram.X® universal-A3 reached a CS plateau value. The tested composites exhibited material-dependent chemo-mechanical properties. Increasing the curing time and/or reducing the composite layer thickness for dentin-shaded composites appears advisable.

Clinical and OCT outcomes of a universal adhesive in a randomized clinical trial after 12 months

ObjectivesTo assess the performance of a universal adhesive in different application modes in non-carious cervical lesions clinically and by optical coherence tomography (OCT). Methods55 adult patients with three non-carious cervical lesions (NCCL) each participated in the study. Lesions were restored with Scotchbond™ Universal (SBU, 3 M) applied in the self-etch (SBU-SE) and the selective-enamel-etch mode (SBU-SEE) in combination with Filtek™ Supreme XTE (3 M). OptiBond™ FL (OFL, Kerr) was used as a control. Restorations were clinically assessed (FDI criteria) after 14 days, 6 and 12 months and in parallel imaged by OCT (interfacial adhesive defects), starting immediately after filling placement. Cumulative failure rates (CFR) and means of interfacial adhesive defect were statistically evaluated. ResultsAfter 12 months, CFRs were lower in the SBU groups (0.0% each) than in the OFL group (20.0%, p = 0.001). Clinically, small marginal fractures occurred three times more often in the SBU-SE than in the SBU-SEE group (p = 0.001). Immediately after filling placement and at each reassessment OCT revealed more interfacial defects at enamel interfaces for SBU/SE compared to SBU/SEE and OFL (pi ≤ 0.044). At dentin/cement more defects were seen with OFL compared to SBU/SE and SBU/SEE (pi ≤ 0.001). Before restoration loss, more interfacial defects appeared compared to remaining restorations (pimmediately/6M = 0.132/0.002). ConclusionsClinical evaluation and OCT imaging revealed higher interfacial integrity for SBU in both application modes compared to OFL. OCT detected interfacial bond failures prior to clinical deterioration or restoration loss. Clinical significanceScotchbond Universal showed an equivalent or improved bonding performance compared to the reference adhesive. Selective enamel etching is recommended. The parameter interfacial adhesive defect seems to be a valuable predictor for evaluation of adhesive restoration systems.

In vitro evaluation of microleakage in Class II composite restorations: High-viscosity bulk-fill vs conventional composites.

This study compared marginal microleakage of Class II cavities restored with bulk-fill resin (Filtek™ Bulk Fill) and conventional composite resin (Filtek™ Supreme XTE). Two standardized Class II cavities were prepared in forty extracted human molars. The gingival margin was located above the cemento-enamel junction for twenty molars (groups 1 and 2) and apically for the other twenty (groups 3 and 4) (n=20). The occlusomesial cavity was filled with bulk-fill resin by insertion in bulk (groups 1 and 3) and the occlusodistal cavity was restored with conventional composite using incremental technique (groups 2 and 4). The teeth were thermocycled (500 cycles 5-55°C), stained and observed under light microscope. The microleakage was significantly lower in gingival margins located in enamel compared with dentin margins (p<0.01). There was no statistically significant difference between groups 1 and 2 (p=0.86) and groups 3 and 4 (p=0.26). Bulk-Fill resins presents gingival microleakage similar to conventional composites.

Antioxidants as a novel dental resin-composite component: Effect on elution and degree of conversion

ObjectiveAscorbic acid (Asc) and N-acetylcysteine (NAC) were reported to reduce genotoxicity induced by dental (co)monomers and their epoxy metabolites. The aim of the present study was to investigate Asc or NAC as novel components in light-curable methacrylate based dental composites regarding their effects on degree of conversion (DC) and elution of composite components. Additionally, the release of Asc or NAC was determined. MethodsAsc or NAC (1, 0.1, 0.01 or 0 wt%) was experimentally incorporated into the composites Venus®, Grandio® and FiltekTM Supreme XTE and polymerized according to the instruction of manufacturers. The samples were elussted in methanol and water. For each composite-antioxidant mixture and elution medium four samples (n = 4) were prepared. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS), high-performance liquid chromatography/ultraviolett/diode array detection (HPLC/UV/DAD) and high-performance liquid chromatography/fluorescence detection (HPLC/FLD). DC of composite-antioxidant mixtures was measured in real-time with Fourier transform infrared spectroscopy (FTIR). ResultsThe highest concentrations of eluted Asc were 313.98 μM (Venus®-1 wt% Asc; 1 day; methanol) and 245.34 μM (FiltekTM Supreme XTE-1 wt% Asc; 5 min; water). The highest concentrations of eluted NAC were 42.99 μM (1 day; Filtek™ Supreme XTE-1 wt% NAC; 1 day; methanol) and 108.11 μM (Filtek™ Supreme XTE-1 wt% NAC; 7 day; water). Triethylene glycol dimethacrylate (TEGDMA) elution was significantly increased in Venus®-1 wt% Asc and Grandio®-1 wt% Asc (1 day and 7 day methanol/water), compared to control. No significant difference was found for TEGDMA elution in Filtek™ Supreme XTE-1 wt% Asc/NAC. DC was significantly decreased compared to control (= composite without antioxidant) in Grandio® and Filtek™ Supreme XTE after 1, 0.1 and 0.01 wt% Asc incorporation and in Venus® after 1 and 0.1 wt% Asc incorporation. For composite-NAC mixtures, only DC of Grandio®-1 wt% NAC was significantly reduced. SignificanceIncorporation of NAC (1 wt%), as a novel composite component, into Filtek™ Supreme XTE, had no effect on DC and composite component elution, and supplies sufficient amount of antioxidant which may reduce toxicity. Therefore, it represents a beneficial mixture.

Modulation of gingival cell response towards dental composites

ObjectiveThis aim of this study was to investigate the cell behavioural response on clinically applied dental composites in exposition-relevant target cells, i.e. human gingival fibroblasts (HGF) and epithelial keratinocytes (HGK). MethodsHGF and HGK were exposed to eluates of Ceram X™, Filtek™ Silorane, Filtek™ Supreme XTE, Fusio™ Liquid Dentin and Vertise™ Flow. Eluates were created by storing material samples in respective cell culture medium, for 24h and 72h (n=17), according to ISO 10993-12:2012. Cell response was evaluated at eluate exposure periods of 24h and 72h by (i) impedance analysis-based real-time monitoring of adhesion and proliferation, (ii) semi-quantitative indirect immunofluorescence (sq-IIF) detection of tissue-specific biomarkers, and (iii) ELISA-detection of pro-inflammatory interleukin (IL)-6. ResultsGenerally, cell behavioural response towards the eluates was gradual in HGK and HGF, the latter exhibiting a less pronounced modulation per se. In HGK, ERK 1/2 was mainly activated after 24h by Fusio™ Liquid Dentin and Vertise™ Flow, while an increase in biomarker expression occurred time-delayed. A 72h exposure of HGK to eluates of Filtek™ Supreme XTE, Fusio™ Liquid Dentin and Vertise™ Flow significantly decreased secreted IL-6 amounts. In HGK, the impedance analysis revealed less proliferation and/or adhesion in case of Fusio™ Liquid Dentin and Vertise™ Flow with matched other composites. SignificanceIn detail, protein expression and secretion is modulated particularly in terms of signal transduction, differentiation and inflammation. On cell biological level, all tested materials modulated the analysed features of cell behaviour with emphasis on the self-adhering composites.

Flowable composites for restoration of non-carious cervical lesions: Results after five years

ObjectivesTo evaluate the clinical performance of two flowable composites for restoration of Class-V non-carious cervical lesions (NCCLs), one with novel (N’Durance® Dimer Flow, Septodont; ND) and one with modified conventional matrix composition (Filtek™ Supreme XTE Flow, 3M-ESPE; FS). The null hypothesis was that both flowable composite materials perform equally regarding clinical quality and survival. Methods50 patients received one ND and one FS restoration of NCCLs in premolars using Clearfil Protect Bond (Kuraray) as an adhesive without additional selective enamel etching. Restorations were evaluated at baseline (BL), after 30 and 60 months employing selected original FDI criteria and refined FDI criteria by separate evaluation of enamel and dentine margins. Non-parametric statistical analyses and χ2 tests were applied (α=0.05). Results38 patients with both restorations under risk were available for the 60-mo recall (recall rate: 76%). At 60-mo, 94.7% of ND and 84.2% of FS restorations were rated clinically acceptable. No significant differences for all selected FDI criteria were recorded between ND and FS at each examination time point except for the criteria surface lustre at 60-mo, where FS showed significantly better results. No significant differences over time could be detected for both materials. There was a trend for more deterioration along the enamel margins than along the dentine margins (criteria marginal staining and marginal adaptation). SignificanceWithin the limitations of the study, the null hypothesis that materials perform equally could not be rejected. Both flowable composites performed similarly regarding clinical performance.

Flowable composites for restoration of non-carious cervical lesions: Three-year results

ObjectivesTo evaluate the clinical performance of two flowable composites for restoring Class-V non-carious cervical lesions (NCCLs), one with novel (ND; N’Durance® Dimer Flow, Septodont) and one with modified conventional matrix composition (FS; Filtek™ Supreme XTE Flow, 3M-ESPE). The null hypothesis was that both flowable composites perform equally regarding clinical quality and survival. Methods50 patients received one ND and one FS restoration of NCCLs in premolars using Clearfil Protect Bond (Kuraray) as an adhesive. Restorations were evaluated by two examiners at baseline (BL), 18 and 36 months employing FDI criteria. Non-parametric statistical analyses and χ2 tests were applied (α=0.05). Results48 patients with both restorations under risk participated in the 36-mo recall. One patient terminated participation after the 18-mo recall. One ND restoration failed at the 18-mo recall (fracture). One FS restoration failed during clinical examination at the 36-mo recall (debonding). 95.8% of restorations each were rated clinically acceptable at 36-mo. No significant differences for all selected FDI criteria were recorded between ND and FS at each examination time point except for the criteria surface staining at 36-mo and marginal staining at 18-mo and 36-mo, where FS showed significantly better results. For each material, no significant differences over time were detected, except for loss of surface lustre for FS (BL to 18 months). SignificanceWithin the limitations of the study, the null hypothesis that materials perform equally could not be rejected. Both flowable composites performed equally regarding survival and similarly regarding clinical performance.