Flowable Resin Research Articles

Interfacial microscopic examination and chemical analysis of resin-dentin interface of self-adhering flowable resin composite

Background: The newly introduced self-adhering flowable resin-composites decrease the required time for application by incorporation of an acidic adhesive monomer, thus reducing the number of the steps, but its bonding is still uncertain. The aim of this study was to evaluate the interfacial microscopic examination and chemical analysis at the resin-dentin interface of a self-adhering flowable resin composite (Vertise-Flow) versus a total-etch (Te-Econom Plus) resin composite, using an etching agent (Eco-Etch gel) and bonding agent (Single Bond Universal). Methods: Sixteen freshly extracted sound human posterior teeth were used. The teeth were randomly divided into two groups: 8 specimens per type of composite. Standard-shaped class V cavities were prepared on the buccal surface. One group was restored by Te-Econom Plus resin composite by total-etch technique using Eco-Etch gel, which was applied to dentine for 15 seconds, followed by rinsing, drying and bonding agent application (Single Bond Universal). The other group restored directly with self-adhering resin composite (Vertise-Flow) without application of etch or bond. Curing was done for 20 seconds using a light emitting diode light curing unit. Evaluation of the resin-dentin interface was done microscopically by examination of marginal gap distance in μm using scanning electron microscope (SEM), and chemical analysis of silver particles was observed using SEM with energy-dispersive X-ray spectrometry after 24 hours of specimen storage in ammoniacal silver nitrate. Results: Regarding marginal gap distance (µm) and silver atomic % mean values, teeth restored with self-adhering resin composite (Vertise-Flow) showed significantly higher mean values than the multi-step etch and rinse resin composite group (5.2 vs 0; 12.2 vs 8.2, respectively). Conclusions: Resin-dentin bonding using total-etch resin composite technique was more effective than self-adhering flowable resin composite (Vertise-Flow) regarding marginal gap formation and penetration of silver particles. Further studies for bond strength could be performed.

Interfacial microscopic examination and chemical analysis of resin-dentin interface of self-adhering flowable resin composite

Background: The newly introduced self-adhering flowable resin-composites decrease the required time for application by incorporation of an acidic adhesive monomer, thus reducing the number of steps, but its bonding is still uncertain. The aim of this study was to evaluate the interfacial microscopic examination and chemical analysis at the resin-dentin interface of a self-adhering flowable resin composite (Vertise™Flow Self-Adhering Flowable Composite, Kerr Dental, USA) versus a total-etch (Te-Econom Plus) resin composite, using an etching agent (Eco-Etch gel) and bonding agent (Single Bond Universal). Methods: Sixteen freshly extracted sound human posterior teeth were used. The teeth were randomly divided into two groups: 8 specimens per type of composite. Standard-shaped class V cavities were prepared on the buccal surface. One group was restored by Te-Econom Plus resin composite by total-etch technique using Eco-Etch gel, which was applied to dentine for 15 seconds, followed by rinsing, drying and bonding agent application (Single Bond Universal). The other group restored directly with self-adhering resin composite (Vertise-Flow) without application of etch or bond. Curing was done for 20 seconds using a light emitting diode light curing unit. Evaluation of the resin-dentin interface was done microscopically by examination of marginal gap distance in μm using scanning electron microscope (SEM), and chemical analysis of silver particles was observed using SEM with energy-dispersive X-ray spectrometry after 24 hours of specimen storage in ammoniacal silver nitrate. Results: Regarding marginal gap distance (µm) and silver atomic % mean values, teeth restored with self-adhering resin composite (Vertise-Flow) showed significantly higher mean values than the multi-step etch and rinse resin composite group (5.2 vs 0; 12.2 vs 8.2, respectively). Conclusions: Resin-dentin bonding using total-etch resin composite technique was more effective than self-adhering flowable resin composite (Vertise-Flow) regarding marginal gap formation and penetration of silver particles. Further studies for bond strength could be performed.

Interfacial microscopic examination and chemical analysis of resin-dentin interface of self-adhering flowable resin composite

Background: The newly introduced self-adhering flowable resin-composites decrease the required time for application by incorporation of an acidic adhesive monomer, thus reducing the number of the steps, but its bonding is still uncertain. The aim of this study was to evaluate the interfacial microscopic examination and chemical analysis at the resin-dentin interface of a self-adhering flowable resin composite (Vertise-Flow) versus a total-etch (Te-Econom Plus) resin composite, using an etching agent (Eco-Etch gel) and bonding agent (Single Bond Universal). Methods: Sixteen freshly extracted sound human posterior teeth were used. The teeth were randomly divided into two groups: 8 specimens per type of composite. Standard-shaped class V cavities were prepared on the buccal surface. One group was restored by Te-Econom Plus resin composite by total-etch technique using Eco-Etch gel, which was applied to dentine for 15 seconds, followed by rinsing, drying and bonding agent application (Single Bond Universal). The other group restored directly with self-adhering resin composite (Vertise-Flow) without application of etch or bond. Curing was done for 20 seconds using a light emitting diode light curing unit. Evaluation of the resin-dentin interface was done microscopically by examination of marginal gap distance in μm using scanning electron microscope (SEM), and chemical analysis of silver particles was observed using SEM with energy-dispersive X-ray spectrometry after 24 hours of specimen storage in ammoniacal silver nitrate. Results: Regarding marginal gap distance (µm) and silver atomic % mean values, teeth restored with self-adhering resin composite (Vertise-Flow) showed significantly higher mean values than the multi-step etch and rinse resin composite group (5.2 vs 0; 12.2 vs 8.2, respectively). Conclusions: Resin-dentin bonding using total-etch resin composite technique was more effective than self-adhering flowable resin composite (Vertise-Flow) regarding marginal gap formation and penetration of silver particles. Further studies for bond strength could be performed.

Effect of dehydration and rehydration intervals on fracture resistance of reattached tooth fragments using a multimode adhesive.

The tooth fragment bonding technique, frequently used to restore traumatized teeth, may be affected by dehydration/rehydration periods. The aim of this study was to evaluate the effects of different dry and wet storage intervals on multimode adhesive bonding between reattached fragments and teeth. Eighty-four bovine incisors were fractured and randomized into groups (n=12). After teeth fracturing, each specimen was assigned to one of the following groups: G0: control group (sound tooth); GA1 and GA2: 1-h dehydration and a 15-min or 24-hours rewetting period, respectively; GB1 and GB2: 24-hours dehydration and a 15-minutes or 24-hours rewetting period, respectively; and GC: 1-hour (GC1) or 24-hours (GC2) dehydration period only. Tooth fragments were then reattached using a multimode adhesive in a self-mode technique with a flowable resin composite. The fracture resistance was evaluated in a universal testing machine under a compressive load (1mm/min-1 ). Data were submitted to two-way analysis of variance and post hoc Tukey test (5%). No significant interaction between dehydration and rehydration intervals was observed (P>.05). Only the step of rehydration significantly affected the reattachment strength when compared to the groups submitted only to dehydration, regardless of the interval (15minutes or 24hours). Rehydrating a tooth fragment for 15minutes before bonding with a multimode adhesive maintained sufficient moisture to increase reattachment strength.

Effect of Endocrown Pulp Chamber Extension Depth on Molar Fracture Resistance.

The purpose of this study was to evaluate the effect of endocrown pulp chamber extension on mandibular molar fracture resistance. A total of 36 recently extracted mandibular third molars of approximate equal size were sectioned at the facial lingual height of contour followed by endodontic access into the pulp chamber. The specimens were then randomly divided into three groups (n=12) and pulpal and root canal contents removed. Pulp chamber floors were established at 2, 3, and 4 mm from the occlusal table using a three-step etch-and-rinse adhesive and a flowable resin composite. The prepared specimens were then embedded in auto-polymerizing denture base resin with surface area available for adhesive bonding determined using a digital recording microscope. Specimens were restored using a standardized template with a chairside computer-aided design/computer-aided manufacturing unit with the endocrown milled from a lithium disilicate glass-ceramic material. Restoration parameters of occlusal table anatomy and thickness were standardized with the only parameter difference being the pulp chamber extension depth. The endocrown restorations were luted with a self-adhesive resin luting agent and tested to failure after 24 hours on a universal testing machine, with force applied to the facial cusps at a 45° angle to the long axis of the tooth. The failure load was converted into stress for each specimen using the available surface area for bonding. Mean failure load and stress among the three groups was first subjected to the Shapiro-Wilk and Bartlett tests and then analyzed with an analysis of variance with the Tukey post hoc test at a 95% confidence level (p=0.05). The 2- and 4-mm chamber extension groups demonstrated the highest fracture resistance stress, with the 3-mm group similar to the 2-mm group. The 3- and 4-mm chamber extension group specimens demonstrated nearly universal catastrophic tooth fracture, whereas half the 2-mm chamber extension group displayed nonrestorable root fractures. Under the conditions of this study, mandibular molars restored with the endocrown technique with 2- and 4-mm pulp chamber extensions displayed greater tooth fracture resistance force as well as stress. All groups demonstrated a high number of catastrophic fractures, but these results may not be clinically significant because the fracture force results are higher than normal reported values of masticatory function.

Marginal integrity of self-adhering flowable composites used as liner under class II restorations: a comparative in vitro micro-CT study

This in vitro study aimed to evaluate the internal adaptation of two different self-adhering flowable composite resin materials used as liners under Class II restorations using microcomputed tomography (micro-CT) analysis. Standard box-only cavities were prepared in 30 extracted human third molar teeth. The cervical floor of the proximal box was 1 mm below the cementoenamel junction. After the preparations were completed, the teeth were randomly and equally divided into three groups based on the type of liner used: group 1, universal flowable composite (control; CO); group 2, self-adhering flowable composite (Fusio Liquid Dentin; FU); and group 3, self-adhering flowable composite (Vertise Flow; VE). After lining, the cavities were restored using 2-mm increments of the nanohybrid composite. After storing the specimens for 24 h in distilled water at 37 °C, all teeth were subjected to 5000 thermal cycles of 5/55 °C. Subsequently, the teeth were immersed in a 50% silver nitrate dye at 23 °C for 4 h. Following the immersion, high-resolution micro-CT images were obtained. Silver nitrate penetration into the microgap between the tooth and restoration was calculated for each specimen as a percentage of the entire length of the pulpal floor using image analysis software. One-way analysis of variance was performed to compare the differences among the groups (p = 0.05). No significant differences were observed between the control and self-adhering composite groups (FU, VE; p > 0.05). The performance of self-adhering composites was similar to that of universal flowable composites in terms of marginal microleakage.

Nanomechanical Characterization of Flowable Dental Restorative Nanocomposite Resins Using AFM

ABSTRACTIn this study, exploring the possible connections between the structure and the functionality of a dental restoration material on the sub-micrometric scale is aimed, especially by focusing on the elastic mechanical properties of materials. Five flowable dental resin composites were investigated by atomic force microscopy nanoindentation. G-ænial™ Universal Flo, Filtek™ Ultimate XT, Vertise™ Flow, Revolution Formula 2™, and Filtek™ Supreme Plus comprising nanofillers have been selected for this study. Young’s modulus was between 12.61 ± 0.35 GPa (for G-ænial™ Universal Flo) and 11.86 ± 0.35 GPa (for Filtek™ Supreme Plus), which were quite similar for all commercial flowable resins.

MICROLEAKAGE AND FACTURE RESISTANCE OF ENDODONTICALLY TREATED TEETH RESTORED WITH BULK-FILL RESTORATIVE MATERIALS

Objective: To evaluate the effect of bulk-fill restorative techniques on microleakage and fracture resistance of endodontically treated teeth.Material and Methods: Eighty maxillary second premolars were selected and randomly divided into four groups (n=20). All teeth received class II cavity preparations followed by endodontic treatment. In Group I, 4mm of flowable bulk-fill material (Tetric EvoFlow Bulk Fill - TEFBF) were applied then overlaid with bulk-fill restorative resin (Tetric EvoCeram Bulk Fill - TECBF). In Group II, only Bulk Fill restorative resin (TECBF) was used to restore the entire preparation. In Group III: 1mm of conventional nanohybrid flowable composite (Tetric EvoFlow - TEF) was applied then overlaid with conventional nanohybrid composite (Tetric EvoCeram - TEC) using incremental layering technique. In Group IV, only conventional nanohybrid composite (TEV) with incremental layering was used. All specimens were then subjected to a thermocycling regimen. Microleakage was evaluated on half of the specimens by dye penetration at the tooth restoration interface. The remaining specimens were subjected to fracture resistance testing under occlusal load and the results analyzed using Kruskal-Wallis and Mann-Whitney U tests, with significance set at p=0.05.Results: Specimens in Groups I and III showed dye penetration reaching the depth of the axial walls while none was observed in Groups II and IV. Groups I and II showed significantly higher fracture strength compared to groups III and IV.Conclusion: 1- The use of bulk-fill restorative technique improved the fracture strength of endodontically treated teeth. 2- The use of bulk fill resin did not affect the cervical microleakage of restorations. 3- Both bulk fill resin and conventional nanohybrid resin restorations have greater tendency for cervical microleakage when flowable resin is used underneath them.

Evaluation of Microleakage and Penetration Ability of Flowable Resin in Occlusal Fissure

본 연구의 ëª©ì ì€ ìœ ë™ì„± ë ˆì§„ì˜ 교합면 열구에서의 침투도와 미세누출을 평가하여 ì¹˜ë©´ì—´êµ¬ì „ìƒ‰ì œë¡œì„œì˜ 사용 가능성을 ê·œëª í•´ ë³´ê³ ìž 하는데 있다.발거된 120개 치아를 4개 군으로 ë¶„ë¥˜í•˜ê³ I군은 대조군으로 ë ˆì§„ê³„ ì¹˜ë©´ì—´êµ¬ì „ìƒ‰ì œë¡œ ì „ìƒ‰, II군은 ìœ ë™ì„± ë ˆì§„ìœ¼ë¡œ ì „ìƒ‰, III군은 ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 도포한 후 ìœ ë™ì„± ë ˆì§„ìœ¼ë¡œ ì „ìƒ‰, IV군은 ì—´êµ¬ì„±í˜•ìˆ ì„ ì‹œí–‰í•˜ê³ ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 도포한 후 ìœ ë™ì„± ë ˆì§„ìœ¼ë¡œ ì „ìƒ‰í•˜ì—¬ 열구 내로의 침투도와 미세누출을 비교 í‰ê°€í•˜ê³ ì£¼ì‚¬ì „ìží˜„ë¯¸ê²½ìœ¼ë¡œ 침투 및 ì ‘ì°©ìƒíƒœë¥¼ 관찰하였다.ìœ ë™ì„± ë ˆì§„ì˜ 열구내 침투도나 미세누출은 ë ˆì§„ê³„ ì „ìƒ‰ì œì— 비해 낮게 나타났으나 ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 도포하거나 ì—´êµ¬ì„±í˜•ìˆ ì„ 시행한 후 ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 도포한 경우는 ë ˆì§„ê³„ ì „ìƒ‰ì œì™€ 침투도의 차이가 없었으며 미세누출은 더 작게 나타났다.ì£¼ì‚¬ì „ìží˜„ë¯¸ê²½ìƒì—ì„œ 열구의 형태나 ì—´êµ¬ì„±í˜•ìˆ ì˜ 여부에 따라 침투도의 차이가 관찰되었으며 ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 사용하지 않은 일부 ìœ ë™ì„± ë ˆì§„ 시편에서는 법랑질 표면과 긴밀한 ì ‘ì°©ì´ 이루어지지 않았다.이상의 결과를 ì¢ í•©í•´ë³´ë©´ ìœ ë™ì„± ë ˆì§„ì€ ì¹˜ë©´ì—´êµ¬ì „ìƒ‰ì œë¡œì„œì˜ ì ìš©ì´ 가능하며 ì—´êµ¬ì„±í˜•ìˆ ê³¼ ìƒì•„ì§ˆì ‘ì°©ì œë¥¼ 사용한다면 침투도를 ë†’ì´ê³ ë¯¸ì„¸ëˆ„ì¶œì„ 줄일 수 있을 것으로 사료된다.

Influence of irradiation by a novel CO2 9.3-μm short-pulsed laser on sealant bond strength.

The objective of this in vitro study was to evaluate whether irradiation of enamel with a novel CO2 9.3-μm short-pulsed laser using energies that enhance caries resistance influences the shear bond strength of composite resin sealants to the irradiated enamel. Seventy bovine and 240 human enamel samples were irradiated with a 9.3-μm carbon dioxide laser (Solea, Convergent Dental, Inc., Natick, MA) with four different laser energies known to enhance caries resistance or ablate enamel (pulse duration from 3μs at 1.6mJ/pulse to 43μs at 14.9mJ/pulse with fluences between 3.3 and 30.4J/cm2, pulse repetition rate between 4.1 and 41.3Hz, beam diameter of 0.25mm and 1-mm spiral pattern, and focus distance of 4-15mm). Irradiation was performed "freehand" or using a computerized, motor-driven stage. Enamel etching was achieved with 37% phosphoric acid (Scotchbond Universal etchant, 3M ESPE, St. Paul, MN). As bonding agent, Adper Single Bond Plus was used followed by placing Z250 Filtek Supreme flowable composite resin (both 3M ESPE). After 24h water storage, a single-plane shear bond test was performed (UltraTester, Ultradent Products, Inc., South Jordan, UT). All laser-irradiated samples showed equal or higher bond strength than non-laser-treated controls. The highest shear bond strength values were observed with the 3-μs pulse duration/0.25-mm laser pattern (mean ± SD = 31.90 ± 2.50MPa), representing a significant 27.4% bond strength increase over the controls (25.04 ± 2.80MPa, P ≤ 0.0001). Two other caries-preventive irradiation (3μs/1mm and 7μs/0.25mm) and one ablative pattern (23μs/0.25mm) achieved significantly increased bond strength compared to the controls. Bovine enamel also showed in all test groups increased shear bond strength over the controls. Computerized motor-driven stage irradiation did not show superior bond strength values over the clinically more relevant freehand irradiation. Enamel that is made caries-resistant with CO2 9.3-μm short-pulsed laser irradiation showed at least equal or significantly higher shear bond strength to pit and fissure sealants than non-laser-irradiated enamel. The risk of a sealant failure due to CO2 9.3-μm short-pulsed laser irradiation appears reduced. If additional laser ablation is required before placing a sealant, the CO2 9.3-μm enamellaser-cut showed equivalent or superior bond strength to a flowable sealant.

Comparison of traditional and simplified methods for repairing CAD/CAM feldspathic ceramics.

PURPOSETo evaluate the adhesion to CAD/CAM feldspathic blocks by failure analysis and shear bond strength test (SBSt) of different restorative systems and different surface treatments, for purpose of moderate chipping repair.MATERIALS AND METHODSA self-adhering flowable composite (Vertise Flow, Kerr) containing bi-functional phosphate monomers and a conventional flowable resin composite (Premise Flow, Kerr) applied with and without adhesive system (Optibond Solo Plus, Kerr) were combined with three different surface treatments (Hydrofluoric Acid Etching, Sandblasting, combination of both) for repairing feldspathic ceramics. Two commercial systems for ceramic repairing were tested as controls (Porcelain Repair Kit, Ultradent, and CoJet System, 3M). SBSt was performed and failure mode was evaluated using a digital microscope. A One-Way ANOVA (Tukey test for post hoc) was applied to the SBSt data and the Fisher's Exact Test was applied to the failure analysis data.RESULTSThe use of resin systems containing bi-functional phosphate monomers combined with hydrofluoric acid etching of the ceramic surface gave the highest values in terms of bond strength and of more favorable failure modalities.CONCLUSIONThe simplified repairing method based on self-adhering flowable resin combined with the use of hydrofluoric acid etching showed high bond strength values and a favorable failure mode. Repairing of ceramic chipping with a self-adhering flowable resin associated with hydrofluoric acid etching showed high bond strength with a less time consuming and technique-sensitive procedure compared to standard procedure.

"Ormocer an innovative technology": A replacement for conventional cements and veneer? A comparative in vitro analysis.

Objective:This in vitro study was designed to assess shear bond strength (SBS) of ormocer flowable (OF) resin as a luting agent, ormocer as an indirect veneer material with portrayal of modes of failures using scanning electron microscope (SEM).Materials and Methods:Sixty maxillary central incisors were divided into Group I, II, and III with 20 samples each based on luting cement used. They were OF, self-adhesive (SA) cement, and total etch (TE) cement. These groups were subdivided into “a” and “b” of ten each based on the type of veneering materials used. Veneer discs were fabricated using Ormocer restorative (O) and pressable ceramic (C). Specimens were thermocycled and loaded under universal testing machine for SBS. The statistical analysis was done using one-way ANOVA post hoc Tukey honest significant difference method.Results:A significant difference was observed between the Groups I and II (P < 0.05). The highest mean bond strength when using ormocer veneer was obtained with the Group Ia (19.11 ± 1.92 Mpa) and lowest by Group IIa (8.1 ± 1.04 Mpa), whereas the highest mean bond strength while using ceramic veneer was of similar range for Group Ib (18.04 ± 4.08 Mpa) and Group IIIb (18.07 ± 1.40 Mpa). SEM analysis revealed OF and TE presented mixed type of failure when compared with SA where failure mode was totally adhesive.Conclusion:OF was found equally efficient like TE. Bond strength of ormocer as a veneer was not inferior to ceramic making it one of the promising additions in the field of dentistry.

Effect of green tea in the colour stability of a flowable composite resin

Effect of green tea in the colour stability of a flowable composite resin

Comparative Evaluation of Marginal Leakage around Cavities restored with Novel Self-adhesive Flowable Composite Resin and Conventional Total Etch-based Resin

Comparative Evaluation of Marginal Leakage around Cavities restored with Novel Self-adhesive Flowable Composite Resin and Conventional Total Etch-based Resin

Characteristics of low polymerization shrinkage flowable resin composites in newly-developed cavity base materials for bulk filling technique.

The purpose of this study was to evaluate polymerization shrinkage and other physical properties of newly-developed cavity base materials for bulk filling technique, with the brand name BULK BASE (BBS). Polymerization shrinkage was measured according to ISO/FDIS 17304. BBS showed the significantly lowest polymerization shrinkage and significantly higher depth of cure than conventional flowable resin composites (p<0.05). The Knoop hardness, flexural strength and elastic modulus of that were significantly lower than conventional flowable resin composites (p<0.05). BBS had the significantly greatest filler content (p<0.05). SEM images of the surface showed failure of fillers. The lowest polymerization shrinkage was due to the incorporation of a new type of low shrinkage monomer, which has urethane moieties. There were no clear correlations between inorganic filler contents and polymerization shrinkage, flexural strength and elastic modulus. In conclusion, the low polymerization shrinkage of BBS will be useful for cavity treatment in dental clinics.

COMPARATIVE STUDY OF SHEAR BOND STRENGTH BETWEEN CONVENTIONAL AND FLOWABLE ORTHODONTIC ADHESIVES

Introduction: Flowable resin composites have been recommended for many clinical uses and have been formulated in a variety of compositions and viscosities to meet various uses.Aim of the work: To determine if flowable composite with or without primers could be used in orthodontic bracket bonding. Materials and Methods: Sixty human premolars and sixty metal brackets were randomly and equally divided into four subgroups. 1A subgroup (TXT with primer), 1B subgroup (TXT without primer), 2A (GF with primer) and 2B (GF without primer). After 72 hours, debonding was performed with a shearing force. The SBS (Shear Bond Strength) and the mode of bond failure were examined with ARI. Another twenty eight teeth were bonded by the same protocol to evaluate microleakage after thermocycling and dying with 2% methylene blue dye for 24 hours.Results: Respective SBS results of the four subgroups were 14.6 ± 5.3, 13.3 ± 6.8, 18.9 ± 6.1 and 12.5 ± 5.9 MPa respectively. SBS value of subgroup 2A were significantly higher than subgroups 1A, 1B and 2B. After debonding ARI scores 0 and 1 were predominant in subgroups 1A, 1B and 2B, where subgroup 2A had ARI scores of 1 and 2. Subgroups 1B and 2B showed microleakage at both bracket-adhesive and enamel- adhesive interfaces, while subgroups 1A and 2A only 43% showed microleakage at bracket-adhesive interface. Conclusions: Flowable composite (GF) can be successfully used for bonding orthodontic brackets as it provided SBS comparable with conventional composite (TXT), as well as can be used without primer as it gives a clinically acceptable SBS and favorable bond failure pattern. However, from microleakage point of view flowable composite (GF) with primer demonstrated the best performance.

Bond Strength Comparison of One-Step/Two-Step Self-Etch Adhesives to Cavity Floor Dentin after 2.5 Years Storage in Water

In recent years, decrease in dentin bond strength of one-step self-etch adhesives after long-term water storage has been reported; however, the flat dentin surface of the extracted tooth has been used to carry out the bond strength tests in the majority of the previous studies. Objectives: The purpose of this study was to compare the micro-tensile-bond-strength (μTBS) of three one-step self-etch adhesives and a two-step self-etch adhesive on the cavity floor dentin after 2.5 years storage in distilled water. Materials and Methods: Adhesives were used in this study: three one-step self-etch adhesives (Primefil, GBOND PLUS and Beauti Bond), and one two-step self-etch adhesive (Clearfil SE Bond), which was used as the control. Bowl-shaped cavities of extracted human incisors were treated with each adhesive and filled with each flowable resin composite from the same manufacturer. The specimens were stored in distilled water at room temperature for two and a half years. The beam samples were made and subjected to μTBS test using the tabletopmaterial- tester. The data were statistically analyzed using one-way ANOVA. Results: The μTBS value of G-BOND PLUS was higher than that of other adhesives; however, the results of ANOVA showed no significant differences in μTBS values among all adhesives. Conclusion: There was no significant difference between one-step and two-step on the bond strength of selfetch adhesives to the cavity dentin floor after a storage period of 2.5 year.

Clinical evaluation of flowable resin composite versus conventional resin composite in carious and noncarious lesions: Systematic review and meta-analysis.

The purpose of this systematic review was to evaluate clinical performance of flowable composite in carious and noncarious lesions. An electronic search was conducted using specific databases (PubMed, Embase, Cochrane Library, and LILACS) through March 2017. Clinical trials for restoration of carious and noncarious lesions were included with no date restrictions; follow-up was 6 months at least and dental restorations were evaluated using the United States Public Health Service criteria. The systematic search generated 908 papers, of which 35 papers were included for full-text review. Inclusion criteria were met by eight papers, six papers were for noncarious lesions and two papers were for restoration of carious lesions. The results of this review have shown no statistical or clinical difference between flowable and conventional composites for all tested outcomes in both carious and noncarious lesions. Both materials have shown clinically acceptable scores for all criteria, with no evidence of clinically unacceptable scores except in retention, with a retention rate of 83% in both materials after 36 months. Flowable composites had clinical efficacy after 3 years of service similar to that of conventional composite in both carious and noncarious lesions, these results are based on low quality of evidence. Based on the available literature and the best available evidence, flowable composites can be used in restoration of noncarious cervical lesions and minimally invasive occlusal cavities.

Evaluating the Microshear Bond Strength and Microleakage of Flowable Composites Containing Zinc Oxide Nano-particles.

IntroductionPreventive resin restorations (PRR) are the conservative choice for the most common carious lesions in children. Thus, new age flowable resin composites with higher filler content are readily used. The aim of this study was to evaluate the microshear bond strength and microleakage of two flowable resin composites containing different percentages of nano zinc oxide (NZnO) particles, which have proven to have antimicrobial properties.MethodsThis experimental in-vitro study was carried out in the Dental Material Research Center of Babol University of Medical Sciences in 2015. One nanohybrid and one nanofill flowable resin composite were chosen and modified with the incorporation of 1% and 3% Wt NZnO particles. Six groups (n=10, 0%, 1%, and 3%) of resin composite sticks on dental enamel (2×2mm) were prepared to be placed in the microtensile tester. The microshear bond strength magnitude (MPa) was recorded at the point of failure. A class I box (3×0.8×1 mm) was prepared on 60 premolars and filled using the resin composites (6 groups, n=10). The specimens were immersed in a 5% basic fuschin solution and sectioned bucco-lingually to view the microleakage using a stereomicroscope. One-way ANOVA and Tukey tests for microshear and Wilcoxon and Kruskal–Wallis tests for microleakage were used to analyze the data in the IBM SPSS Statistics version 22 software.ResultsThe bond strength of the 3% clearfill group significantly decreased while no significant change occurred in the bond strength in other groups. The Z-350 group had significantly lower microleakage as nanoparticles increased. No significant difference was observed in the clearfill group.ConclusionUp to 3% Wt incorporation of NZnO particles will not diversely alter the bond strength, but it will be beneficial in providing antimicrobial effects with lower microleakage rates.

Microshear bond strength to dentin of self-adhesive flowable composite compared with total-etch and all-in-one adhesives

Background/purposeBecause of the lack of data on long-term survival of a flowable self-adhesive composite (SAC) restoration, the purpose of this study was to compare the microshear bond strengths (μSBSs) of flowable resin composites to dentin, either with self-adhesive ability or with the combined use of a total-etch adhesive and all-in-one adhesive, before and after thermocycling. Materials and methodsCoronal dentin specimens of 60 extracted sound third human molars were divided into three groups (n=20) as follows: Group 1, flowable SAC (VF); Group 2, total-etch adhesive+flowable composite (FL); Group 3, all-in-one adhesive+flowable composite (AL). For each adhesive, half of the specimens were subjected to μSBS testing after 24-hour water storage, and the other half of the specimens were subjected to 5000 thermocycles followed by μSBS testing. The morphologies of the adhesive interfaces were evaluated under a scanning electron microscope. Data were analyzed using one-way analysis of variance (ANOVA) and independent t test. ResultsOne-way ANOVA showed similar results for both 24-hour water storage and thermocycled groups. The FL group showed the highest μSBS values (P<0.001). The VF and AL groups were not statistically significantly different. Thermocycling had no effect on μSBS values (P=0.578). The interfacial observation revealed that VF had a gap at the resin–dentin interface. By contrast, both FL and AL specimens had distinct adhesive layers without any gap formation. ConclusionThe results from this study indicated that laboratory bonding effectiveness of flowable SAC was approximately that of all-in-one adhesive.