FiltekTM Z350 XT Research Articles

Physical/mechanical and antibacterial properties of composite resin modified with selenium nanoparticles

BackgroundAccumulation of biofilm over composite resin restorations is one of the principal causes of recurrent caries. Therefore, this study aimed to develop antibacterial composite resins by crystalline selenium nanoparticles (SeNPs), assessing the antibacterial, mechanical, and physical properties of the composite resin after SeNPs incorporation.MethodsSeNPs were synthesized via a green method. The nanoparticles were characterized by UV-Vis spectroscopy, fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The nano-filled composite (Filtek™ Z350XT ) was considered as a control group (G0). Two concentrations of SeNPs (0.005 wt% and 0.01 wt%.) were added to the tested resin composite (G1& G2), respectively. The physical/mechanical and antibacterial properties of the composite specimens (n = 10/group) were characterized. A one-way ANOVA was conducted to analyze these data followed by Bonferroni post hoc test for pairwise comparison.ResultsModified composites with SeNPs showed antibacterial activity against E. coli and S. mutans. Mechanical properties including diametral tensile strength, compressive strength, or surface roughness were not affected by nano-incorporation compared to control. Furthermore, the degree of conversion showed no statistical difference. However, SeNPs incorporation into resin composite produces color change that can be visually perceived.ConclusionsThe green synthesized SeNPs significantly improved the antimicrobial properties of the dental composite without compromising mechanical performance. However, it shows color change after SeNPs incorporation.

Water Sorption and Solubility of Highly Aesthetic Single-Shade Nano-Hybrid Resin Composites.

Background A single-shade resin composite is a new type of resin composite that was introduced in 2019. There is not much data regarding the water sorption (Wsp) and water solubility (Wsl) of this type of resin composite. Therefore, this study aimed to investigate Wsp and Wsl and their effects on the surface roughness of a single-shade nano-hybrid resin composite in comparison with a conventional nano-hybrid resin composite in accordance with ISO 4049:2019 (Dentistry - Polymer-based Restorative Materials). Material and methods An in vitro study was performed to investigate the Wsp and Wsl of a single-shade supra-nano-hybrid composite (Omnichroma) and a conventional nano-hybrid composite (Filtek™ Z250 XT) in accordance with ISO 4049:2019. Five disks were prepared of each material with dimensions of 15 ± 1 mm in diameter and 1 ± 0.1 mm in thickness, as per ISO 4049:2019. The results were calculated according to the ISO equations for Wsp and Wsl in µg/mm3. Atomic force microscopy (AFM) was used to analyze the surface roughness (Ra) of test specimens. Results The findings showed that the values of Wsl and Wsp of both materials are comparable and revealed no statistically significant difference (P > 0.05). The AFM images showed a higher Ra post-solubility testing, and the statistical analysis indicated a significant difference for both materials. Conclusions The study concluded that the single-shade resin composite (Omnichroma) and the conventional nano-hybrid composite (Filtek™ Z250 XT) are following the requirements of ISO 4049:2019. The AFM analysis indicated that resin composite surfaces are significantly affected when exposed to water for a prolonged period of time. However, the Ra variations of Filtek™ Z250 XT were higher than Omnichroma specimens. These results indicate that resin composite surfaces can be significantly impacted by prolonged water exposure. This knowledge is critical for enhancing the long-term clinical performance and durability of these dental restorative materials.

An influence of preheating composites on microleakage- An invitro study

Resin composites have become one of the widely used restorative materials in the field of dentistry. Resin composite Pre-heating is a recent innovative method that is clinically beneficial by improving handling and marginal adaptation of the resin to the tooth. The study aims to determine the effect of temperature on the degree of microleakage in resin composite restorations. In the present study, Class 1 cavity was prepared in 30 extracted non-carious human premolars and divided into two groups. Group A (n=15) - filled with nano-hybrid resin composite (3M™ Filtek™ Z350 XT Universal Composite) at room temperature. Group B (n=15) - filled with the same resin preheated and then checked for micro-leakage under SEM. Mann-Whitney test was used to compare the mean Marginal Leakage scores between the 2 groups. There was a statistically significant difference in the micro-leakage score between group A and group B. Group B showed minimal or no micro-leakage in comparison to Group A. Preheating the resin composite has better adaptability to the walls thus reducing micro-leakage and postoperative sensitivity.

Flexural strength and degree of conversion of universal single shade resin-based composites

Background/purposeRecently, a group of universal single-shade resin-based composites (RBCs) has been developed to simplify the process of shade selection. Excellent mechanical and physical properties are crucial for the ultimate success and clinical longevity of restorations. Therefore, evaluating the properties of the single-shaded RBCs is imperative. This study aimed to determine the flexural strength (FS) and degree of conversion (DC) of universal single-shade RBCs. Materials and methodsIn this study, four commercial RBCs were used; three universal single-shade RBCs; Omnichroma (OC), Charisma® Diamond ONE (CD), and Vittra APS Unique (VU), and a conventional nanohybrid composite Filtek™ Z250 XT (FT) which was used as a control. Sixty composite beams and 40 composite discs were used for FS and DC, respectively. A universal test machine with a three-point bending test was used to measure the FS, whereas the DC was measured using a Fourier-transform infrared spectrometer (FTIR). Three fractured specimens from each resin composite group were qualitatively analyzed using scanning electron microscopy. ResultsANOVA was used to compare the mean values of FS and DC among the four RBCs (OC, CD, VU, and FT). Highly significant differences were observed in the mean FS and DC values (F = 673.043, p < 0.001 and F (=782.4, p < 0.0001), respectively. The highest FS was observed in the CD group, followed by FT and VU groups; the lowest value was observed in the OC group. In addition, a statistically significant difference was identified in DC values. The highest DC value was observed in VU, followed by OC and CD, and the lowest DC value was observed in FT. ConclusionUniversal single-shade RBCs demonstrated a good FS, except for OC, which exhibited a significantly low FS. The DC of the universal single-shade RBCs was higher than that of the conventional nanohybrid composite restorative material.

Surface roughness of two composite resins after immersion in soda drinks: in vitro study

Compare the surface roughness of two composite resins after immersion in carbonated beverages. 160 resin discs (6 x 2 mm) were divided into 8 groups (n=20 per group) according to type of resin (Filtek™ Z350 XT® and Palfique LX5®) and type of immersion in beverages (distilled water, Coca Cola®, Inca Kola® and Kola Escocesa®. The immersions were carried out under a structured cycle: 4 immersions a day for 5 days, intermediate storage in distilled water and overnight incubation for 8 h at 37°C. The measurements with the roughness meter were evaluated in three times: baseline, 7 and 14 days. The three-way Anova test was used at P<0.05. Roughness showed differences only for the individual factors of time (P<0.000) and resin (P=0.000), and for the interaction time*drink (P=0.000) and resin*drink (P=0.003). Roughness was higher with Filtek Z350 XT® immersed with Inca Kola® (0.85 ± 0.37) than 14 days compared to other times (P=0.035) and with Palfique LX5 immersed in Coca Cola® at 7 days (1.61 ± 0.42) and in Inca Kola® at 14 days (1.66 ± 0.56) compared to distilled water (P<0,05). Surface roughness was affected by the type of resin, the type of soft drink and the immersion time. The roughness was greater with the Palfique LX5® nanohybrid resin, the Inca Kola® drink and after 14 days of immersion.

Effect of different finishing and polishing systems on surface properties of universal single shade resin-based composites

BackgroundRecently, universal single-shade resin composites have become increasingly available in the dental market. The modification of their composition can have an inadvertent effect on their physical and surface properties, and subsequently determinantal effect on their clinical function and longevity. Therefore, this study aimed to evaluate the effect of different finishing and polishing (F/P) systems on surface roughness (Ra), surface gloss (GU), and Vickers microhardness (VMH) of universal single-shade RBCs.Materials and methodsFour commercial RBCs were used; the universal single-shade RBCs were Omnichroma, Charisma® Diamond ONE, and Vittra APS Unique, and a conventional nanocomposite Filtek™ Z250 XT was used as a control. The 3 F/P systems were Sof-Lex™ XT, Enhance®/PoGo®, and Diacomp® Plus Twist. A total of 160 discs were used for the 3 F/P system groups for all RBCs (n = 10). After F/P, the Ra, GU, and VMH were assessed. The data were analyzed using 2-way ANOVA at p-value < 0.05.ResultsSignificant differences were found among the four RBCs and the 3 F/P systems (p < .000). Omnichroma showed the lowest Ra and acceptable GU, but the lowest VMH. Charisma showed the highest Ra, acceptable GU, and VMH. Vittra showed acceptable Ra, GU, and VMH and Filtek showed the highest GU, VMH, and acceptable Ra.ConclusionAlthough conventional nanohybrid RBC (Filtek Z250 XT) showed better GU and VMH values, the universal single-shade RBCs demonstrated comparable surface properties. The highest GU & VMH and lowest Ra were achieved by Diacomp followed by Enhance and Soflex.

In Vitro Effect of Mouthrinses on the Microhardness of Three Different Nanohybrid Composite Resins.

Daily use of different mouthrinses at home or in the dental office can alter the properties of resin hardness. The present study aimed to compare Vickers microhardness (VHN) in vitro of nanohybrid composite resins (NCRs) immersed in mouthrinses. In total, 120 discs (10 ⨯ 2 mm) were prepared from three NCR shade A2 (n = 40/group) with FiltekTM Z350 XT (Z350XT), Tetric EvoCeram (TEC), and Polofil NHT (PNHT). The specimens were incubated in artificial saliva (37°C ⨯ 24 hr). Specimens were distributed into four mouthrinses (n = 10/group) of artificial saliva (control), chlorhexidine (CHX 0.12%, pH 5.6), cetylpyridine chloride (CPC 0.075%, pH 5.84), and CHX 0.12% + CPC 0.05% (pH 6.2) (2 times/day, 2' ⨯ 12 hr). The VHN (300 gf/10") was measured after 24 hr, 14, and 21 days. Data were analyzed by three-way analysis of variance, followed by post hoc Tukey analysis at 0.05 level of significance. The results revealed a global effect of the interaction of the mouthrinses ⨯ time between NRC evaluated (P=0.001). Baseline VHN in PNHT and Z350XT was higher than TEC. Within each group of NCR, VHN of CHX + CPC > other mouthrinses (PNHT/14 days; Z350XT/21 days), and >CPC (Z350XT/14 days). In mouthrinses-intragroups, VHN of PNHT and Z350XT decreased at 14 days (CHX, CPC) and was maintained over time in NCR (CHX + CPC). VHN-TEC was similar among groups. Microhardness showed differences due to the interaction of the type of NCR, the composition of the mouthrinses, and time. VHN decreased after 14 days and was more affected in composite resins with lower filler content and in mouthrinses with a lower pH.

A comparative study on the depth of cure, hardness and microleakage applied to primary teeth of different types of bulk-fill resins

Objective: To compare the depth of cure, surface hardness and microleakage applied to primary teeth of three types of bulk-fill resins, so as to provide reference for clinical application. Methods: Composite resin FiltekTM Z350 XT (group A) and giomer Beautifil Ⅱ (group B) were used as controls, high-viscosity bulk-fill resin FiltekTM Bulk Fill (group C), sonic-activated bulk-fill resin SonicFill 2 (group D) and flowable bulk-fill resin SDR® flow+(group E) were studied. The microstructure of each group was observed by scanning electron microscope (SEM). Specimens of each group were prepared (6 pieces per group), and the Vickers microhardness of the surface layer and different depths of each group were measured, and then the depths of cure were calculated. Twenty-five primary molars dentin were filled by resins of each group (5 teeth per group), sliced, then aged, slices of each group were developed by silver ion staining. SEM was used to observed the distribution of silver ions. Microleakage of each group were analyzed by Jonckheere-Terpstra rank sum test. Results: SEM showed that the filler particles in groups A and C were spherical and evenly distributed. The shape of the fillers in groups B, D and E were polygonal and unevenly distributed. The surface hardness of groups A, B, C, D and E were (84.97±6.30), (65.04±5.95), (57.80±1.18), (60.77±2.34), (33.32±1.83) MPa respectively. Group A had the highest hardness, while group E was the lowest, and the differences between the two groups and other groups was statistically significant (P<0.05). There were no statistically significant differences among groups B, C, and D (P>0.05). The curing depths of groups A, B, C, D and E were 2.6, 3.4, 5.8, 3.8 and 7.8 mm respectively. The largest microleakage was found in group E [2% (1/50) for grade 0, 22% (11/50) for grade 1, 30% (15/50) for grade 2, 24% (12/50) for grade 3, and 22% (11/50)for grade 4], which was statistically different from other groups (P<0.05). No statistically significant differences were found among other 3 groups (P>0.05). Conclusions: Both high-viscosity and sonic-activated bulk-fill resins have the greater depth of cure, the same hardness and microleakage as giomer, which might be an option for restoration in primary teeth.

Staining Susceptibility of Microhybrid and Nanohybrid Composites on Exposure to Different Color Solutions

Composite discoloration is considered one of the most significant disadvantages of dental restorations. The purpose of our study was to assess the color susceptibility of two esthetic composite filling materials, microhybrid composite (ValuxTM Plus) and nanohybrid composite (FiltekTM Z250 XT), to different solutions and compare the results among different measuring methods (Intraoral scanner, Easyshade spectrophotometer, and Vita classical shade guide). A total of 100 specimens were fabricated in this experimental study. Each sample was soaked in either Coca-Cola, orange juice, tea, coffee, or distilled water for 30 days. Color measurement was performed using the spectrophotometer, IOS 3Shape Trios, and Vita classical shade guide. L*a*b* values were recorded to determine the color changing (ΔE00). The significance level was p &lt; 0.05. All samples showed clinically visible color changes after immersion in coffee, tea, orange juice, and Coca-Cola. The nanohybrid composite showed high color change when placed in tea (ΔE00 = 12.5) measured by the Intraoral scanner, spectrophotometer (ΔE00 = 23.21), and by Vita classical shade guide (ΔE00 = 25). Less color discoloration was perceptible in the microhybrid composite when immersed in Coca-Cola (ΔE00 = 1.78) measured by spectrophotometer, intraoral scanner (ΔE00 = 2.85), and measured by Vita classical shade (ΔE00 = 3.2). The results showed that measurements with the spectrophotometer and Vita classical shade guide were correlated. The results were analyzed using the chi-square and Wilcoxon signed-rank tests, and there was a significant difference (p &lt; 0.001) in both composite resins for all the solutions, with microhybrid being more color stable. Microhybrid composite had more color stability than nanohybrid composite, especially when immersed in tea and coffee. The spectrophotometer with Vita classical shade guide showed better interrater agreement than with the intraoral scanner.

Effect of a demineralization model on the microhardness, surface roughness and topography of giomers: An in vitro study.

The purpose of this study is to compare the effect of a demineralization model on the microhardness, surface roughness, and topography of giomers.Seventy-two discs of six different dental materials in three different presentations (pit and fissure sealant (PFS), flowable and restorative materials) were divided into six groups (n = 12 p/g). Three experimental groups (giomers) consisted of BeautiSealant, Beautifil Flow Plus, and Beautifil II, and three control groups (resin-based materials) were formed using ClinproTM, FiltekTM Z350 XT Flow, and Filtek™ Bulk Fill materials. Vickers microhardness, surface roughness, and topographic analysis with atomic force microscopy were measured at the beginning (0) after four (1) and 7 days (2) of immersion in a demineralizing model. Statistical analysis was performed using One-way and Repeated Measures ANOVA and Pearson's correlation coefficient (p ≤ .05). The microhardness values showed significant variations, except for the G_RM group. All the groups presented significant increases in roughness through the experiment stages, except for RB_PFS in the Ra parameter. The topographic analysis showed variations in the micromorphology, especially in the experimental group at the end of the demineralization model. Finally, there was no correlation between microhardness and surface roughness. The demineralization model decreased the microhardness, with the lowest reductions in the giomers groups. The effect of the demineralizing model on the surface roughness and topography showed an increase in specific patterns for the experimental and control groups. Therefore, their clinical use is recommended. RESEARCH HIGHLIGHTS: The demineralization model decreased the microhardness property of the evaluated materials, with better performance for the giomer groups. The effect of the demineralizing model on surface roughness showed an increase with specific patterns for the experimental and control groups. Although the materials presented changes in their microhardness, roughness, and topography, their clinical use is recommended.

Evaluation of Bioactive Restorative Materials' Color Stability: Effect of Immersion Media and Thermocycling.

One of the most important aspects that determines the clinical lifetime of aesthetic restorations, is the color stability (CS) over the long term. This study aims to assess the effect of artificial aging and thermocycling in different staining solutions on the CS of bioactive restorative materials compared to conventional ones. The following four material groups were investigated: ACTIVA™ Bioactive (AB) (Pulpdent Corporation, Massachusetts, United States), Beautifil II (BF) (SHOFU Inc., Kyoto, Japan), Fuji II (FJ) (GC Corporation, Tokyo Japan), and Filtek™ Z350 XT (FT) (3M, Minnesota, United States). A total of 100 specimens were fabricated using an acrylic mold and then immersed in five staining solutions groups: coffee, black tea, Cola, mixed berry juice, and saline. Baseline shade (T0) was recorded using two spectro-photometer devices, VITA Easyshade® Advance (VITA Zahnfabrik, Baden-Wurttemberg, Germany) and Color-Eye® 7000A (X-Rite, Inc., Grand Rapids, Michigan, United States). Following this, the shade was recorded at 30 days (T1), three months (T2), and after 5000 thermocycles (5C-55C) (T3). CIE L*a*b* (International Commission on Illumination color space) data was used to calculate ΔE for each group. All samples showed a significant color change (P<0.001) following one and three months of storage and after thermocycling. AB and BF showed the highest CS over time, whereas FT and FJ showed the least CS. The CS of restorative materials is mostly determined by their type, followed by staining solution type and thermocycling. The most potent solutions were coffee, tea, and berry juice.

Staining ability of herbal tea preparations on a nano-filled composite restorative material - an in-vitro study.

Background: Discoloration of tooth-colored restorations due to various factors is one of the principal causes behind the failure of aesthetics. There has been an surge in the consumption of herbal beverages in recent times and the dietary factors play a potential role in the discoloration tooth-coloured restorations. This study was done to juxtapose the staining ability of green tea (GT), moringa tea (MT), and hibiscus tea (HT) on a nano-filled composite restorative material. Methods: The study was conducted in-vitro on composite samples prepared using moulds. 112 discs were prepared from Filtek TM Z350XT composite using a brass mould lined with mylar strips. Samples were divided into GT, MT, HT, and artificial saliva (AS) groups and immersed in freshly prepared beverages for 15 minutes each day for 45 days. Digital reflectance spectrophotometer was utilized to record color at baseline, 30, and 45 days. Repeated-measures ANOVA with a post-hoc Bonferroni test was used to compare groups within each group. ANOVA with a post-hoc Games Howell test was used to compare mean differences in ΔE among the groups. Results: Maximum discoloration was observed in the GT, followed by HT and MT, with the least being in the AS group at the end of 30 and 45 days (P<0.001 and P<0.001) respectively. Conclusions: The universal nano-filled composite material showed clinically detectable discoloration when exposed to Green Tea, Hibiscus Tea, and Moringa Tea which increased with time. Herbal beverages have the potential to cause discoloration of the composite resin which is often the choice of material for anterior aesthetic restorations.

INFLUENCES OF DIFFERENT SOLUTIONS ON THE COLOUR STABILITY AND MICROHARDNESS OF CONTEMPORARY LIGHT CURED COMPOSITES: AN IN VITRO STUDY Received 2022-12-09; Accepted 2023-03-18; Published 202

Despite the accumulation of dental plaque, adsorption of colourant pigment from foods and beverages was found to influence the quality of aesthetic restorations. The study aimed to evaluate the influence of different solutions on colour stability and microhardness of microhybrid and nanofilled composite resins. This project was a laboratory based experimental study. Three types of composite resins were used; microhybrid (FiltekTM Z250), nanohybrid (FiltekTM Z250 XT) and universal nanocomposite (FiltekTM 350 XT). A total of 135 disc-shaped specimens were prepared and were randomly divided into five subgroups (n = 9): artificial saliva, mouthwash, carbonated drink, energy drink and coffee. Samples were immersed in the solutions at time intervals of 24 hours, 7 days, 14 days, 21 days and 28 days. All specimens were assessed for the staining effect using a spectrometer (QE65000) and microhardness evaluation using the Vickers indenter (LECO LM 248AT, St. Joseph, Michigan, USA). Data on spectrometer colour spectrum and surface hardness were subjected to a one-way ANOVA and Tukey HSD test at a significance level of P &lt; 0.05. There was a significant difference in discolouration between all three types of composite resins when immersed in all solutions regardless of the pH values (P &lt; 0.05). Vickers hardness test showed statistically significant microhardness among all composite resins on Day 28. The staining medium caused significant discolouration and decreased the hardness of all the materials tested. Microhybrid composite resin reported the lowest colour variations and resistance to hardness test.

The impact of the diode laser 940 nm photoactivated bleaching on color change of different composite resin restorations.

The study's main objective was to evaluate as well as compare the impact of diode laser 940 nm and conventional in-office bleaching technique on the color change of different composite resin restorations. A total of ninety composite resin discs (CRDs) were made from Filtek™ Bulk Fill, nanohybrid composite resin Filtek™ Z550 XT Universal Restorative, and flowable composite resin restoration Filtek™ Z350xt Flowable Composite. Group A: (30) CRD for Filtek™ Bulk Fill, group B: (30) CRD for Filtek™ Z550 XT Universal Restorative, and group C: (30) CRD for Filtek™ Z350xt Flowable Composite. A1, B1, and C1: (10 CRD in each group): Control group without bleaching. A2, B2, and C2: 10 CRD in each group bleached with Laser White20 without laser activation. A3, B3, and C3: 10 CRD in each group bleached with Laser White20 and activated by diode laser 940 nm. The color was evaluated using a dental spectrophotometer. One-way ANOVA was utilized for the comparison of the color stability of the CRD. P < 0.05 is regarded as statically significant. Both conventional and diode laser in-office vital tooth bleaching protocols affected the color stability of composite resin restorations. The result demonstrated that bleaching without laser activation produced color change (mean [8.30], standard deviation [SD] (1.95) P [< 0.001]), whereas the bleaching and activation by diode laser produced color change (mean [8.11], SD [1.99], P [< 0.001]). Both types of bleaching protocol affected composite resin restorations' color stability. In all tested materials, color changes after the bleaching protocol were clinically perceptible. The restorations following the bleaching procedure are required to be replaced by clinicians.

Clinical effectiveness of alkasite versus nanofilled resin composite in the restoration of occlusal carious lesions in permanent molar teeth of children: a randomized clinical trial

PurposeTo evaluate and compare the clinical effectiveness of alkasite with nanofilled resin composite restorations for occlusal caries lesions in permanent molar teeth of children, at one-year follow-up.MethodsIn this randomized controlled clinical trial with parallel design, 38 children aged 7–13 years with occlusal caries lesions on 59 first permanent molars were randomly allocated into two groups, Group 1: Filtek™ Z350XT (nanocomposite) and Group 2: Cention N® (alkasite resin composite). The restorations were evaluated at one year using the United States Public Health Service (USPHS) criteria. Data were analyzed using Chi-square or Fisher’s exact test.ResultsAll restorations had either Alpha or Bravo scores at one-year follow-up. In Group 1, all restorations scored Alpha, while one restoration each (3.6%) in Group 2 scored Bravo for fracture and marginal adaptation. All restorations in both groups scored Alpha for retention, secondary caries, and post-operative sensitivity. For anatomic form, all restorations in Group 1 scored Alpha, while three (10.7%) restorations in Group 2 had Bravo scores. For marginal discolouration, three restorations in both groups scored Bravo (11.5% and 10.7%, respectively). For surface roughness, one restoration (3.8%) in Group 1 and three restorations in Group 2 (10.7%) scored Bravo. The comparative results between the two groups for all the variables in the USPHS criteria were not statistically significantly different.ConclusionsThe performances of the nanofilled composite and alkasite were clinically acceptable and comparable. Alkasite can be an alternative material for the restoration of occlusal caries lesions in permanent molars of children.Clinical trial registrationThe clinical trial was registered at Clinical Trials Registry—India (CTRI Reg no: CTRI/2020/12/029830 Dated: 15/12/2020).

Evaluation of Fracture Resistance in Maxillary Premolar Teeth Restored with Different Direct Composite Restorative Material

Purpose: This study was conducted to evaluate the effect of three direct resin composite restorative materials on fracture resistance in mesio-occluso-distal (MOD) cavities prepared in maxillary premolars. Materials and Methods: A total of 25 maxillary premolars were collected and then divided into five main groups (n=5). Group 1 (positive control group): sound teeth with no cavity preparation. Group 2 (negative control group): MOD cavities with no restoration. Group 3: MOD cavities restored with nanocomposite FILTEK™ Z350 XT Group 4: MOD cavities restored with simplified universal composite OptiShade™ and Group 5: MOD cavities restored with universal nano-filled composite Estelite® Sigma Quick. Results: Group 5 showed the maximum fracture strength value (ranged from 1170-1355 N) followed by Group 4 (998.1- 1158 N) then Group 3 (900.9-1097 N) followed by Group 1 (positive control) with fracture strength value ranging from 836.1 to 1059 N. Group 2 (negative control) showed the minimum fracture strength value ranged (380.6-631.6 N). For the significance evaluation of different groups, One-Way ANOVA was performed followed by Tukey`s post hoc test for multiple comparisons which revealed all significant differences between different groups as P-value &lt; 0.05 except for (group 1 # group 3), (group 1 # group 4) and (group 3 # group 4) respectively which were insignificantly different as P-value &gt; 0.05. Conclusion: Reinforcement of the teeth could be achieved after MOD cavity preparation in maxillary premolars through proper restorative procedures.

Effect of shape of titanium dioxide nanofillers on the properties of dental composites

The main objective of the present study was to evaluate the effect of the morphology of titanium dioxide nanofillers on the flexural strength and shear bond strength of the dental composite. Spherical and rhombic-shaped nano titanium dioxide fillers were synthesized via solvothermal method and were characterized. Subsequently, these fillers were incorporated into a flowable composite (Filtek™ Z350 XT Flowable Restorative) at 0.5 wt.% and 1.5 wt.% and the prepared specimens were stored in water for 24 h. The specimens were then evaluated for flexural strength using a universal testing machine. Similarly, the shear bond strength of modified composites to the tooth was evaluated and bond failures were analyzed using stereomicroscope magnification. Incorporation of nanofillers significantly enhanced the flexural strength of flowable composite (p = 0.009) with a significant increase at 0.5wt.% of spherical (p = 0.015) and rhomboidal-shaped fillers (p = 0.010). However, no statistically significant difference in flexural strength was observed among the different shapes of nanofillers. The results of our study did not show a significant effect on the shear bond strength of the composites. Thus the reinforcing ability of titanium dioxide nanofillers on dental composite was confirmed in this study, although the effect of using nanofillers with different morphology was not significant.Graphical abstract

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.

Efeito da termociclagem na microdureza interna de resinas compostas bulk fill de alta e baixa viscosidade aplicadas em cavidades classe I

ABSTRACT Objective: To evaluate the effect of thermocycling on the Knoop internal microhardness of high- and low viscosity bulk fill resins applied in Class I cavities. Methods: Thirty third molars with Class I cavity preparations were randomly divided into 3 groups according to the restorative system: nanoparticulated composite resin (Filtek™ Z350 XT 3M ESPE) (oblique increments of 2mm); low viscosity bulk fill resin (Filtek™ Bulk fill Flow, 3M ESPE) (3mm increments covered with a 1-mm layer of nanoparticulated resin); high viscosity bulk fill resin (Filtek™ Bulk fill, 3M ESPE) (single 4-mm increment). After 24h, half of samples was submitted to thermocycling (1,000 cycles). All samples (n=5) were sectioned in half to measure the internal microhardness at bottom and top of restoration. Results: Analysis of variance indicated that, for nanoparticulated composite resin, without thermocycling, the microhardness at the top was statistically lower than at the bottom. After thermocycling, there was no difference in microhardness between the top and the bottom. For low viscosity bulk fill resin, without thermocycling, there was no significant difference in microhardness means between the top and the bottom. After thermocycling, significantly higher microhardness was found at the top than at the bottom (p &lt;0.05). For high viscosity bulk fill resin there was no significant difference between the microhardness values at the top and bottom, regardless of thermocycling (p&gt; 0.05). In all composite resins, an increase in microhardness was observed after thermocycling (p &lt;0.05). Conclusion: Thermocycling increased the internal microhardness of resin restorations, and, for the low viscosity bulk fill resin, the microhardness at the top was higher than at the bottom after thermocycling.

Staining ability of herbal tea preparations on a nano-filled composite restorative material – an in-vitro study

Background: Discoloration of tooth-colored restorations due to various factors is one of the principal causes behind the failure of aesthetics. There has been an surge in the consumption of herbal beverages in recent times and the dietary factors play a potential role in the discoloration tooth-coloured restorations. This study was done to juxtapose the staining ability of green tea (GT), moringa tea (MT), and hibiscus tea (HT) on a nano-filled composite restorative material. Methods: The study was conducted in-vitro on composite samples prepared using moulds. 112 discs were prepared from FiltekTM Z350XT composite using a brass mould lined with mylar strips. Samples were divided into GT, MT, HT, and artificial saliva (AS) groups and immersed in freshly prepared beverages for 15 minutes each day for 45 days. Digital reflectance spectrophotometer was utilized to record color at baseline, 30, and 45 days. Repeated-measures ANOVA with a post-hoc Bonferroni test was used to compare groups within each group. ANOVA with a post-hoc Games Howell test was used to compare mean differences in ΔE among the groups. Results: Maximum discoloration was observed in the GT, followed by HT and MT, with the least being in the AS group at the end of 30 and 45 days (P&lt;0.001 and P&lt;0.001) respectively. Conclusions: The universal nano-filled composite material showed clinically detectable discoloration when exposed to Green Tea, Hibiscus Tea, and Moringa Tea which increased with time. Herbal beverages have the potential to cause discoloration of the composite resin which is often the choice of material for anterior aesthetic restorations.