Effect of Various Etching Techniques on Shear Strength of Newer Generation Composites.

Aim: To evaluate the effect of lasers on the shear bond strength of Giomer and G-aenial flo composite using three different etching techniques. Materials and Methods: 60 Samples (extracted human premolar teeth) are cut horizontally using a diamond disk to expose a flat occlusal surface involving enamel and dentin. On exposed occlusal surfaces, etching is done by various methods. These were divided into six groups of ten samples each as follows: group I (acid etched for Giomer), group II (acid etched for G-aenial flo composite), group III (laser etched for Giomer), group IV (Laser etched for G-aenial flo composite), group V (air abrasion etched for Giomer), group VI (Air abrasion etched for G-aenial flo composite). Then, restorative material is placed and cured with light for 20 seconds. The samples were thermocycled to simulate the oral environment. The samples were subjected to a universal testing machine for bond strength testing at a cross-head speed of 3 mm/min until the restoration will fracture. Results: The intergroup comparison between both the materials using Student's t-test gives insignificant results. The intergroup comparison between different etching techniques using two-way ANOVA tests gives insignificant results. Conclusion: Within the limitation of this study, it can be concluded that Giomer and G-aenial flo composite achieved the same shear bond strength in all the etching techniques.

Influence of Cavity Lining on the 3-Year Clinical Outcome of Posterior Composite Restorations: A Randomized Controlled Clinical Trial.

The purpose of this randomized, split-mouth-designed controlled and single-blinded clinical study was to evaluate the 3-year clinical performance of Class I and Class II resin composite restorations placed with or without cavity lining with a flowable composite. Fifty patients with treatment needs in two premolars or molars were included. One of the teeth was restored using the nanohybrid composite (Grandio®SO, control group), in the test group a high viscosity flowable composite was additionally applied as a first layer. In both groups, the same self-etch adhesive system was applied. Clinical evaluation after 3 years was carried out using the modified USPHS/Ryge criteria. At the 3-year follow-up the recall rate was 92%. Four restorations failed in the test group (8.7%), three due to the loss of vitality and one after fracture. The control group exhibited a cumulative success rate of 100%, while the test group achieved a success rate of 91.3%. This led to significant differences in the annual failure rate (AFR) between the two groups, with rates of 0% and 2.9% (p < 0.05; Mann-Whitney U-test). After 3 years the cumulative survival rate including all restorations was 95.7%. Statistical analysis revealed significant differences for the parameters: tooth vitality, marginal discoloration, success rate, and AFR. The other parameters exhibited no significant differences. Consequently, the nanohybrid composite demonstrated excellent performance over a 3-year period, whereas the utilization of a flowable composite for the cavity lining did not appear to exert a beneficial influence on clinical outcomes.

Evaluation of the amount of residual monomer released from different flowable composite resins.

Today, resin materials are used in the restoration of permanent and deciduous teeth or as fissure sealants. The materials can contain different types of monomers (Bis-GMA, UDMA, TEGDMA). These monomers can be released into the oral cavity after polymerization. Residual monomers released from resin-containing restorative materials after polymerization have been reported to have negative effects on mechanical properties. The aim of our study is to evaluate the amount of residual monomers released after polymerization of different flowable composite resin materials using two different modes of LED light source. Composite disc samples (8 mm diameter/2 mm depth) prepared for each material group were polymerized using two different modes of the LED light device (Standard mode and extra power mode). HPLC (High Performance Liquid Chromatography) device was used to measure the amount of residual monomer release at 1 h, 1 day, 3 days and 7 days periods. Pairwise comparison of the differences between the materials was performed by Post-hoc test. For each residual monomer, the Kruskal Wallis test was used to analyze the difference between the materials in standard mode and the difference between the materials in extra power mode. According to the results of the study; Grandio flow flowable composite showed the highest release of TEGDMA and Bis-GMA while SDR® Flow flowable composite showed the lowest release of TEGDMA, Bis-GMA and UDMA. For all materials, the extra power mode resulted in more residual monomer release. TEGDMA and Bis-GMA release was detected in all tested flowable composites at all time periods.

Effect of silver diamine fluoride on the microleakage of flowable resin composite and glass ionomer cement restorations to carious primary dentin: an-in vitro study.

BACKGROUND: This study aimed to evaluate the effect of Silver Diamine Fluoride (SDF) on the microleakage of flowable resin composite (FRC) and resin-modified glass ionomer cement (GIC) restorations bound to carious primary dentin. METHODS: Forty-four extracted carious primary molars were allocated into four groups as follows (n = 11 teeth/group): Group I, Flowable resin composite (FRCa): SDF38% treatment + FRC, Group II, Flowable resin composite (FRCb): FRC without SDF treatment, Group III, Resin-modified glass ionomer cement (GICa): SDF38% treatment + GIC, Group IV, Resin-modified glass ionomer cement (GICb): GIC without SDF treatment. Specimens were subjected to thermo cycling at 500 cycles between 5 to 55 °C (dwell time of 60 seconds) in baths before being immersed for 24 h in a 1% toluidine blue solution. Microleakage testing was conducted for each specimen in two areas; occlusal and gingival. Specimens were evaluated under stereomicroscope at 4x magnification. Results were analyzed using Kruskal-Wallis test followed by pairwise comparisons utilizing Dunn's post hoc test at p ≤ 0.05. RESULTS: Insignificant differences between different groups (p = 0.49) were observed at the gingival walls area readings. The highest value was found in GICb (2.33 ± 0.52), while the lowest value was found in FRCa (1.71 ± 0.76). Insignificant differences between different groups (p = 0.982) were observed at the occlusal walls area readings. The highest value was found in FRCa (1.43 ± 0.98), while the lowest value was found in GICb (1.17 ± 1.33). CONCLUSION: SDF does not adversely affect the microleakage of FRC and GIC restorations bound to carious primary dentin.

Assessment of a highly-filled flowable composite for the repair of indirect composites.

PURPOSE: To compare the shear-bond-strength (SBS) of a highly-filled-flowable composite (HFFC) and a paste-type composite for indirect composite repair and to evaluate the effect of different surface treatments (ST), concerning the composite repair protocol. METHODS: Eighty-four 5 × 5 × 2 mm cylindrical specimens were prepared using Gradia Plus and SR Nexco indirect composite materials. The samples were thermocycled 5,000 times. According to the ST, the samples were divided into three groups (control, bur, and air-abrasion). After ST, the sample subgroups were divided into two sub-groups according to the repair material: paste-type composite and HFFC (n = 7). Another 5,000 cycles of aging were performed. SBS values were measured with a universal testing machine (Shimadzu, Japan). Shapiro-Wilk, 3-way ANOVA, and Tukey HSD test were used to evaluate data (P < 0.05). RESULTS: ST was considered significant for SBS (P < 0.001). The mean values were (13.9 ± 5.7), (17.0 ± 6.4), (20.4 ± 4.9) MPa for the control, bur and phosphoric acid, and air-abrasion groups, respectively. The surface treatment and repair material interaction was considered significant for SBS (P = 0.044). The highest mean bond strength (24.5 ± 4.5 MPa) was observed for the interaction of SR Nexco, air-abrasion ST, and HFFC repair. CONCLUSION: Repairing with HFFC following air abrasion might enhance the SBS for indirect composite restorations.

Repair bond strength of a new self-adhesive composite resin to three different resin-matrix ceramic CAD-CAM materials.

This study aimed to evaluate the shear bond strength of two flowable composite resins to resin-matrix ceramic CAD-CAM materials.Fifty-four plates obtained from Lava Ultimate (LU), Cerasmart (CS), and Vita Enamic (VE) CAD-CAM blocks were assigned to nine groups: N0: Nova Compo SF (NCSF), N1: Silane/Single Bond Universal (SBU)/NCSF, N2: SBU/NCSF, N3: Silane/G-Premio Bond (GPB)/NCSF, N4: GPB/NCSF, G1: Silane/SBU/G-aenial Universal Injectable Composite (GUIC), G2: SBU/GUIC, G3: Silane/GPB/GUIC, G4: GPB/GUIC. After the repair procedures, shear bond strength values were analyzed. Silane pre-application decreased bond strength in most LU and CS groups but increased it in VE. NCSF performed better than GUIC in all CAD-CAM's with similar adhesive protocols. SBU in combination with NSCF had the highest bond strength among all repair procedures in LU and CS. Silane-containing universal adhesives in combination with self-adhesive resin composites should be used to repair resin-matrix ceramic materials.

In vitro wear resistance of conventional and flowable composites containing various filler types after thermomechanical loading.

OBJECTIVE: To comparatively assess the wear resistance of conventional and flowable composites containing different filler types using thermomechanical chewing simulation. MATERIALS AND METHODS: Six different composite resin materials were used: a conventional and flowable composite from each of three manufacturers respectively classified by different filler characterizations: (1), a nanohybrid conventional (G-aenial Posterior, GC) and flowable (G-aenial Universal Injectable, GC), (2) a nanofilled conventional (Filtek One Bulk-fill Restorative, 3M) and flowable (Filtek Ultimate Flow, 3M), and submicron-filled conventional (Estelite Posterior Quick, Tokuyama) and flowable (Estelite Bulk-Fill Flow, Tokuyama). The buccal surfaces of extracted human premolars were planarly abraded and used as control (n = 12). The prepared surfaces were subjected to wear using a thermocycler chewing simulator against 6-mm diameter steatite balls for 240,000 cycles, simulating 1 year of in vivo use. Digital profiles of treated sample surfaces were scanned using a laser scanner, and the volume loss and maximum depth of loss were calculated. Two-way MANOVA was used to compare the wear volume loss and depth according viscosity (conventional/flowable) and filler type (nanohybrid, nanofilled, submicron-filled), and multiple comparisons were performed using Duncan's test. RESULTS: Wear volume loss and loss depth were significantly lower in enamel than in all composite resin groups. The wear volume loss and loss depth of nanofilled composites were significantly higher than the other composite filler types, with no significant difference in either parameter between the nanohybrid and submicron-filled composite groups. With respect to apparent viscosity, wear volume loss and loss depth of conventional composites were significantly lower than the flowable composites. CONCLUSIONS: The type of composite filler and its apparent viscosity significantly influence the in vitro wear resistance of the material. All composite materials tested demonstrated a susceptibility to simulated wear that was two to three times greater than that of human enamel. CLINICAL SIGNIFICANCE: Flowable composite resins provide a level of convenience in clinical application. Despite advancements in their wear characteristics, they continue to display inferior wear resistance compared to conventional composite resins. Nevertheless, all tested composite resins exhibited a significantly higher potential for wear than human enamel.

Degree of conversion and physicomechanical properties of newly developed flowable composite derived from rice husk using urethane dimethacrylate monomer.

This study evaluated the use of urethane dimethacrylate (UDMA) as a base monomer to prepare the newly developed flowable composite (FC) using nanohybrid silica derived from rice husk in comparison to bisphenol A-glycidyl methacrylate (Bis-GMA) on the degree of conversion and physicomechanical properties. The different loadings of base monomer to diluent monomer were used at the ratio of 40:60, 50:50, and 60:40. The bonding analysis confirmed the presence of nanohybrid silica in the newly developed FC. Independent t-test revealed a statistically significant increase in the degree of conversion, depth of cure and Vickers hardness of the UDMA-based FC, while surface roughness showed comparable results between the two base monomers. In conclusion, UDMA-based FC demonstrated superior performance with 60%-65% conversions, a significantly higher depth of cure exceeding 1 mm which complies with the Internal Standard of Organization 4049 (ISO 4049), and a substantial increase in Vickers hardness numbers compared to Bis-GMA-based FC, making UDMA a suitable alternative to Bis-GMA as a base monomer in the formulation of this newly developed FC derived from rice husk.

Effect of immediate dentin sealing on the fracture strength of indirect overlay restorations using different types of luting agents (A comparative in vitro study).

Objective: This study evaluates the effects of immediate dentin sealing (IDS) on the fracture resistance of lithium disilicate overlays using three different types of resin-luting agents (preheated composite, dual-cure adhesive resin, and flowable composite). Materials and Methods: Forty-eight maxillary first premolars of equal size were prepared using a butt joint preparation design. The teeth were separated into two primary groups, each with 24 teeth: Group DDS - delay dentin sealing (DDS) (non-IDS) teeth were not treated. Group IDS - dentin sealing was applied immediately after teeth preparations. Each group was subsequently separated into three separate subgroups of eight teeth. Subgroups DDS+Phc and IDS+Phc - cemented with preheated composite (Enamel plus HRi, Micerium, Italy), subgroups DDS+Dcrs and IDS+Dcrs - cemented with dual-cured resin cement (RelyX Ultimate, 3M ESPE, Germany), and subgroups DDS+Fc and IDS+Fc - cemented with flowable composite (Filtek Supreme Flowable, 3M ESPE, USA). The fracture resistance of each sample was evaluated using a test of a single load till failure, which was automatically recorded in Newton by a computer-controlled universal testing system. Results: The fracture resistance of the subgroup IDS+Phc was the highest mean value, in which the overlay was cemented with preheated composite (1954 N), and the lowest mean was noted in the subgroup DDS+Fc, by which the overlay cemented with flowable composite without IDS (887 N). All IDS subgroups had a high mean fracture load. Both the Bonferroni test and the one-way ANOVA test identified a significant difference between all groups of 0.05. Conclusion: In general, teeth with IDS were stronger than teeth without IDS. When the preheated composite is used as a luting agent improves overall fracture resistance, followed by resin cement and flowable composite, respectively. However, the result showed that the ceramic overlays with and without IDS are strong enough to withstand the normal mastication force. Overlays was failed in a more catastrophic, irreparable mode of fracture than the clinical situation.

Effect of different industrialized acid beverages on the surface roughness of flowable composite resins: in vitro study.

Flowable composite resins are materials available for restorations in pediatric dentistry. However, these materials are subject to dangerous effects in the oral environment caused by acids that deteriorate and increase their roughness. Therefore it is important to evaluate the effect of different industrialized acid beverages on the roughness of flowable composite resins. An in vitro experimental study, was done using a convenience sample of 132 discs of 5 mm diameter by 2 mm depth of four flowable materials (FF (Filtek™ Z350 XT Flowable), TNF (Tetric® N-Flow), PF (PermaFlo®) and GF (Grandio® Flow)) exposed to three beverages (CC (Coca-Cola), AJ (apple juice), and FM (fermented milk)) and incubated at 37 ºC for 0, 15 and 30 days. The roughness (average roughness (Ra) and maximum height of profile (Rz) parameters) was measured at different intervals of time with a profilometer. For the data analysis, one-way analysis of variance (one-way ANOVA) and repeated measures analysis of variance (Repeated measures ANOVA) tests were applied (p < 0.05). In the roughness test before immersion, no differences were observed within the groups, with maximum roughness values for Filtek™ Z350 XT Flowable and minimum for PermaFlo®. However, at 15 and 30 days of immersion, the groups showed significant differences depending on the immersion drink, except Grandio® Flow in apple juice and fermented milk. The flowable materials studied presented specific behaviors according to the immersion period and drink used. The Filtek™ Z350 XT Flowable showed a similar increase in surface roughness independently of the drink used. Grandio® Flow was the most stable material against surface roughness changes after beverage immersion.

Self-adhesive flowable composite resins and flowable composite resins in permanent teeth with occlusal cavities: A systematic review and meta-analysis.

OBJECTIVES: To compare the clinical performance (retention, secondary caries, marginal adaptation, marginal discoloration, and postoperative hypersensitivity) of self-adhesive flowable composite resins (SAFCs) and flowable composite resins (FCs) in permanent teeth with occlusal cavities. DATA: Randomized controlled trials (RCTs) of SAFCs versus FCs with a follow-up length of at least one year. No restrictions were placed on language or publication date. SOURCES: Five databases, including PubMed, Embase, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials, were searched manually by browsing ten related journals. On 14 June 2023, all electronic and manual searches were updated. STUDY SELECTION: Five RCTs with 138 participants were included. Cochrane's risk of bias tool (2.0) was implemented in selected studies, and the GRADE tool was utilised to evaluate the evidence quality. To summarize the effects of the treatments and pool the data, a random-effects model was used. CONCLUSIONS: According to the modified United States Public Health Service Evaluation (USPHS) criteria, there was no discernible difference between the groups during the two-year follow-up period (maximum follow-up time). Nevertheless, FCs applied with the etch-and-rinse mode demonstrated superior marginal adaptation and marginal discoloration at the two-year follow-up (relative risk = 3.21 [1.50 to 6.83], 3.40 [1.10, 10.48]). The evidence for marginal discoloration at any recall time and marginal adaptation at the one-year follow-up was graded as moderate quality due to inconsistency. Moreover, low-quality evidence for marginal adaptation at two-year follow-up was due to imprecision and inconsistency. CLINICAL SIGNIFICANCE: SAFCs exhibited clinical performance comparable to that of FCs in occlusal cavities. Further high-quality clinical trials are needed to provide solid evidence to support the clinical application of SAFCs. REGISTRATION: PROSPERO (CRD42022374983).

Cuspal deflection of teeth restored with bulk fill flowable composite resins, with and without fiber-reinforcement and evaluated by Micro-computed Tomography.

Polymerisation shrinkage of composite resins is a clinical challenge which has been well documented in the literature. Many studies investigating polymerisation shrinkage stress measure cuspal deflection, which is a manifestation of this stress. The introduction of flowable bulk-fill composite (BFRBC) materials has streamlined the restorative process, though the shrinkage and cuspal deflection from these BFRBCs has not been compared with regards to its use with polyethylene fibers (Ribbond fibers). The authors describe a method to measure the cuspal deflection of flowable BFRBCs placed in cavities of standardised dimensions at distinct steps of the restorative process, with and without fiber-reinforcement and using x-ray micro-computed tomography. Co-ordinate points are established on the buccal and lingual aspects of scanned specimens using the Volume Graphics VG Studio max 3.2.5 (Hiedelberg, Germany 2018) software. The system allows for these landmarks to be established across each scan (of the same tooth), ensuring standardization of each specimen. Further anatomical points are used to enable analysis. Comparison of angles generated across these points determines the extent of cuspal deflection.•A method of measuring the cuspal deflection of composite resins is proposed.•Experimental procedures are provided.•Data analysis methods are outlined.

Investigating the impact of flowable composite liner on the fracture strength and microleakage of large composite resin restorations of primary anterior teeth.

PURPOSE: To investigate the effect of pre-cured and co-cured flowable composite liner on fracture strength and microleakage of primary anterior teeth with extended composite resin restorations. METHODS: In the current in vitro experimental study, the crowns of 54 extracted primary canine teeth were cut 1 mm above the CEJ, and a pulpectomy procedure was performed. The samples were randomly divided into three groups to restore the coronal part up to 4 mm above the CEJ. In group 1, the samples were built up with Filtek Z250 packable composite resin. In group 2 (pre-cure), first, 1 mm of Filtek Z350 XT flowable liner was applied to the sample, and after curing, the restoration process continued using packable composite resin. In group 3 (co-cure), the flowable composite liner was cured while the first layer of packable composite resin was applied; then, the same restorative procedure similar to the other groups was followed. The samples' cross-sectional area in the fracture strength test was calculated by AutoCAD software. Subsequently, the samples were subjected to a force in a universal testing machine. The samples related to the microleakage experiment were cut vertically, and then, the dye penetration percentage (10% methylene blue) was measured under a stereomicroscope. ANOVA was used to analyze the data. RESULTS: Mean fracture strength in group 2 was significantly higher than in group 1 (P = 0.016). The microleakage mean in group 3 was significantly lower than in groups 1 (P = 0.000) and 2 (P = 0.026). CONCLUSION: The flowable composite liner and its relevant separate curing increased the fracture strength of composite resin restorations. However, less microleakage was reported in the group where the liner was applied as a co-cure.

Effect of Type of Resin Composite Material on Porosity, Interfacial Gaps and Microhardness of Small Class I Restorations.

AIM: This study aimed to compare the best restorative approach for the conservative class I cavity by comparing flowable and nanohybrid composites versus the placement technique regarding surface microhardness, porosity, and presence of interface gaps. MATERIALS AND METHODS: Forty human molars were divided into four groups (n = 10). Standardized class I cavities were prepared and restored using one of the following materials: Group I - Flowable composite placed by incremental technique; group II - Flowable composite placed in one increment; group III - Nanohybrid composite placed by incremental technique; and group IV - Nano-hybrid composite placed in one increment. After finishing and polishing, specimens were sectioned into two halves. One section was chosen randomly for the Vickers microhardness (HV) evaluation and the other section was used for the assessment of porosities and interfacial adaptation (IA). RESULTS: The surface microhardness range was 28.5-76.2 (p < 0.05), mean pulpal microhardness range was 27.6-74.4 (p < 0.05). Flowable composites had lower HV than conventional counterparts. The mean pulpal HV of all materials exceeded 80% of occlusal HV. Restorative approaches did not statistically differ in porosities. However, IA percentages were higher in flowable materials compared to nanocomposites. CONCLUSION: Flowable resin composite materials have lower microhardness than Nanohybrid composites. In small class I cavities, the number of porosities was similar between the different placement techniques and the interfacial gaps were highest in the flowable composites. CLINICAL SIGNIFICANCE: The use of nanohybrid resin composite to restore class I cavities will result in better hardness and less interfacial gaps compared to flowable composites.

Antibacterial activity and shear bond strength of fiber-reinforced composites and bonding agents containing 0.5%, 1%, 2.5%, and 5% silver nanoparticles.

Background: Bonded composites may increase bacterial accumulation and caries formation risk. Therefore, assessment of methods to decrease bacterial activity around them would be valuable. The literature on the efficacy of adding silver nanoparticles to fiber-reinforced composite (FRC) or adding them to bonding agents in terms of their antibacterial activity and/or shear bond strength (SBS) is scarce. Thus, we aimed to assess the antibacterial activity of flowable composites and bonding agents containing various percentages of experimental silver nanoparticles (nanosilver) against S. mutans and to evaluate the SBS of FRC and bonding agents containing different amounts of nanosilver to enamel. Materials and Methods: In this preliminary study, 0% (control), 0.5%, 1%, 2.5%, and 5% nanosilver were added to flowable composite and bonding agent. Syntheses of nanosilver and nanosilver-incorporated composite specimens were approved using X-ray diffraction spectroscopy and scanning electron microscopy. Antibacterial effects of the produced materials on S. mutans were evaluated by colony count with serial dilution method (n = 7 groups × 10 [n = 70] specimens) and agar disc diffusion test (n = 6 groups × 5 [n = 30] composite specimens + n = 6 groups × 5 [n = 30] light-cured bonding + n = 6 groups × 5 [n = 30] uncured bonding) against negative control and cefotaxime antibiotic. Moreover, SBS values of various FRC blocks bonded to enamel using various bonding agents were measured (n = 9 groups × 6 [n = 54] human premolars). Data were analyzed using Kruskal-Wallis, Dunn, two-way analysis of variance, and Tukey's tests (α = 0.05). Results: Composite discs containing all concentrations of nanosilver reduced S. mutans colony counts (P < 0.05); bacterial growth was ceased at samples containing 2.5% and 5% of nanosilver. The reduction in the SBS of FRCs was significant only for 5% nanosilver (P < 0.05). Conclusion: Adding 0.5%, 1%, and 2.5% nanosilver to composite and 0.5% or 1% nanosilver to bonding agent led to a significant antibacterial behavior against S. mutans while not significantly affecting the SBS of FRC.

12 Month's Assessment Of Clinical Efficacy Of Resin Modified Glass Ionomer Cement And Flowable Composites In Restoration Of Non-Carious Cervical Lesions, A Randomized Clinical Trial.

Background: The objective of this study was to compare the clinical efficacy of Resin modified glass ionomer cement and Flowable composite in terms of retention, marginal adaptation and surface texture using United States Public Health Service criteria in non-carious cervical lesions measured over a period of one year. Methods: A Randomized Clinical Trial is conducted with Informed consent on 60 patients who are randomly allocated into 2 groups with at least 2 Non Carious Cervical Lesions in each. Group 1 is used for Flowable Composite while group 2 is used for resin modified glass ionomer cement. A recall is maintained to draw conclusions between two materials in terms of occurrence of marginal adaptation, retention and surface texture, to show which material is superior to other. Results: Out of 30 restorations in 12 months follow up, only 19 found to be present in flowable composite group while in resin modified glass ionomer cement group, 28 are retained. Regarding margin integrity, Group 1 showed 21 intact margins whereas 23 margins were intact in group 2, while 18 and 25 showed smooth surface in flowable composite and Resin modified glass ionomer cement group respectively, on exploration. Conclusion: It can be concluded from our study that Resin modified glass ionomer cement is superior to Flowable composite in terms of retention (p=0.005) and surface texture (p=0.045) in restoration of non carious cervical lesion.

Experimental two-step universal adhesives bond durably in a challenging high C-factor cavity model.

OBJECTIVES: To determine the bonding effectiveness of experimental 2-step universal adhesives (UAs) to high C-factor class-I cavity-bottom dentin and to assess the potential bond-strength contribution of an additional flowable composite layer. METHODS: Three experimental 2-step UA formulations, involving the application of a 10-MDP-based primer followed by a hydrophobic adhesive resin with a 15-to-20-µm film thickness and differing only for filler, referred to as BZF-21 (silica and bioglass filler), BZF-29 (silica filler) and BZF-29_hv (higher silica-filler loading resulting in a higher viscosity), all prepared by GC, along with three representative commercial adhesives, Clearfil SE Bond 2 (C-SE2, Kuraray Noritake), G-Premio Bond (G-PrB, GC) and OptiBond FL (Opti-FL, Kerr), were comparatively investigated for their 'immediate' and 'aged' (50,000 thermocycles) micro-tensile bond strength (µTBS), when applied either in etch-and-rinse (E&R) or self-etch (SE) mode, to high C-factor class-I cavity-bottom dentin (n = 10; 10 experimental groups). Four additional experimental groups involved the extra application of the flowable composite G-ænial Universal Flo (GC), employed as an intermediate liner in combination with the adhesives BZF-29 and G-PrB and again applied both in E&R or SE mode. Statistical analysis was performed using linear mixed-effects (LME) modelling and linear regression analysis (p < 0.05). RESULTS: All 2-step UAs performed similarly when compared to the gold-standard E&R Opti-FL and SE C-SE2 adhesives, except for the aged µTBS of BZF-29_hv applied in E&R mode, and significantly outperformed the 1-step UA G-PrB. Significant reduction in µTBS upon aging was only recorded for 2-step UAs applied in E&R mode. The extra flowable composite layer significantly improved G-PrB's µTBS. SIGNIFICANCE: The experimental 2-step UAs revealed favorable bonding performance in the challenging high C-factor class-I cavity model, comparable to that of the multi-step gold-standard E&R and SE adhesives and superior to that of the 1-step UA investigated. An additionally applied flowable composite layer compensated for the lower bonding effectiveness of the 1-step UA in the high C-factor cavity model.

Clinical evaluation of bioactive resin-modified glass ionomer and giomer in restoring primary molars: A randomized, parallel-group, and split-mouth controlled clinical study.

Aim: This study aims to evaluate and compare the clinical performance of two restorative materials - bioactive resin-modified glass ionomer (ACTIVA BioACTIVE restorative) and giomer hybrid composite (Beautifil Flow Plus) in restoring class I carious primary molars. Materials and Methods: The split-mouth randomized controlled study was conducted on 100 primary molars from 50 children (28 - males, 22 - females) from 50 children in age range of 5-9 years (Mean-7.29±1.34) with at least two occlusal carious lesions on either maxillary or mandibular primary molars. Each child had both the control and the experimental teeth restored with respective restorative materials, Group I (Control, n = 50) → Giomer, Group II (Experimental, n = 50) → Bioactive resin-modified glass ionomer. The restorations were evaluated by two independent investigators using modified United State Public Health Service criteria at immediate postoperative, 6 months, and 12 months. The Chi-square test was used for the statistical analysis after collecting the data. Results: At the 12-month follow-up, 33 children (66 teeth) reported with an attrition rate of 33%. The color match between the groups was not statistically significant at all intervals. The marginal discoloration, marginal integrity, anatomic form, and retention had no significant difference at 6 months. But at 12 months, there was a statistically significant difference between the groups with p value of 0.04,<0.001,<0.02 and <0.001 respectively. respectively. At 12 months, there was no postoperative sensitivity in both groups. Conclusion: Bioactive resin-modified glass ionomer with enhanced properties can be used as an effective restorative material, especially in children with excessive salivation.

Comparative Evaluation of Shear Bond Strength of Nanohybrid Composite Restoration After the Placement of Flowable Compomer and Composite Using the Snowplow Technique.

AIM: Based on the importance of bonding during restoration, this in vitro study aimed to evaluate the difference in shear bond strength of nanohybrid composite restoration in molars after the placement of flowable compomer and composite using the snowplow technique. MATERIALS AND METHODS: Twenty-four freshly extracted molars were taken and sectioned at the level of 2.5 mm from the coronal cusp and root tip. These sections were embedded in methacrylate and, after etching and bonding, were randomly divided into two groups (n=12) for placement of restorative materials. In group A, the plastic tube was filled with uncured flowable composite resin followed by the placement of packable nanohybrid composite in oblique increments. In group B, the plastic tube was filled with uncured flowable compomer followed by the placement of packable nanohybrid composite in oblique increments. Each specimen was then tested under a universal testing machine to determine the shear bond strength. RESULTS: Independent sample 't' test revealed a statistically significant difference between the mean shear bond strength of compomer and composite (P value<0.001), where flowable composite showed higher values compared to compomer.  Conclusion: It was seen that the use of composite showed a significantly better bond strength of the restoration when compared to compomer using the snowplow technique. Both materials and application techniques can influence the bond strength of a material as determined in this study.

Clinical Evaluation of the Retention of Self-adhering Flowable Composite as Fissure Sealant in 6-9-year-old Children: A Randomized Controlled Trial.

Aim: To evaluate the retention rate of self-adhering flowable composite as fissure sealant in comparison with the unfilled resin sealant on first permanent molars of 6-9-year-old children. Materials and methods: A 2-arm, split-mouth randomized controlled trial included 100 children of age 6-9 years with completely erupted mandibular first permanent molars. A total of 200 teeth were randomly divided into two groups, group I: self-adhering flowable composite; group II: unfilled resin sealant. Sealants were placed on the mandibular first permanent molars and the children were recalled at 6, 12, and 18 months intervals to evaluate the retention rate. Chi-square test was used to analyze the data. Results: Self-adhering flowable composite has shown a complete retention rate of 67%, 47%, and 46% at 6, 12, and 18-month intervals, respectively, whereas unfilled resin sealant has shown 41%, 8%, and 5% retention rate at 6, 12, and 18-month intervals, respectively. The difference in the complete sealant retention rates between the groups is found to be statistically highly significant at all the follow-up intervals (p = 0.0004, 0.0001, and 0.0001 at 6, 12, and 18-month intervals, respectively). In both groups, maximum sealant loss occurred between 6 and 12-month intervals. Retention rates were higher at 6 months intervals which were significantly reduced over 18 months intervals. Conclusion: Self-adhering flowable composite has shown a higher retention rate compared to unfilled resin sealant at all the time intervals. The retention rate of both materials decreased with time. However, the loss of sealant was more with unfilled resin sealant. Clinical significance: In pediatric dental practice, the elimination of a step in restorative dentistry protocol makes a big difference as time is a critical factor in obtaining children's cooperation. The use of self-adhering materials eliminates the step of bonding agent application, which simplifies the restorative protocol and makes the clinical practice effective. Therefore, these self-adhering flowable composite resin materials can be considered fissure sealants in routine clinical practice. How to cite this article: Bhuvaneswari P, Vinay C, Uloopi KS, et al. Clinical Evaluation of the Retention of Self-adhering Flowable Composite as Fissure Sealant in 6-9-year-old Children: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2022;15(3):322-326.