Nanohybrid Composite Resin Research Articles

The Effect of Se ect of Several Electric Cigar al Electric Cigarette Puffs on Nanohybrid ette Puffs on Nanohybrid Composite Resin Surface Roughness

Nanohybrid composite resin is a dental restorative material comprising micro and nano-sized fillers. When accompanied by smoking habits, it can alter the surface roughness of composite resin. Objective: This study aimed to determine the effect of several electric cigarette (e-cigarette) puffs on the surface roughness of nanohybrid composite resin. Methods: This study was conducted in the experimental laboratory with a pretest-posttest control group design using 48 nanohybrid composite resin specimens divided into six groups. Subsequently, the experimental groups were exposed to 75, 150, 225, 300, and 450 puffs of e-cigarette, and the control group was given artificial saliva immersion without exposure for 21 days. The surface roughness of specimens was measured with a surface roughness tester and evaluated through statistical analysis, including One-Way ANOVA and Post-Hoc LSD. Results: The average pre-test and post-test differences between groups I, II, III, IV, V, and VI were 0.013, 0.022, 0.033, 0.044, 0.065, and 0.005 μm. These results showed a significant difference in the surface roughness of nanohybrid composite resin (p < 0.05), with variations between all groups. Conclusion: This study showed that the number of e-cigarette puffs had a significant effect on the surface roughness of nanohybrid composite resin. Specifically, an increase in the number of e-cigarette puffs led to a rise in the surface roughness value of nanohybrid composite resin.

Effect of different tea solutions on the color stability of composite resins

Aims: The aim of this study is to evaluate the color change of supra-nanophile (Estelite ? Quick) and nano-hybrid (Clearfil Majesty Esthetic) composites kept in three different brands of black tea (İstikan, Yellow Label and Çaykur) for three different periods (24 hours, 7 days and 28 days). Methods: Specially produced Teflon molds with an inner diameter of 10 mm, an outer diameter of 12 mm, and a thickness of 2 mm were used. 28 pieces of Tokuyama Estelite Sigma Quick composite material and 28 pieces of Kuraray Clearfil Majesty Esthetic composite material were placed in the molds and polimerized. All samples were polished and initial color measurements were taken. The samples were divided into three experimental groups (Istikan, Lipton yellow label, Çaykur tiryaki) and a control group (distilled water) (n=7). The samples were kept in this solution for 1 day, 7 days and 28 days, and at the end of the period, color measurements were measured with a spectrophotometer. Data were recorded according to the CIE Lab system. One-way analysis of variance (ANOVA) and Tukey test were used to analyze the data, and the Kruskal Wallis H test was used to make comparisons based on variables with more than two categories in the data. Results: It was observed that there was a statistically significant difference between the 24-hour and 7th-day coloration results of Tokuyama brand according to the beverages (p<0.05). According to the beverages, it was observed that there was a statistically significant difference between the 28-day coloration results of Tokuyama and Kuraray brands. Conclusion: In the supra-nanofilled and nanohybrid filler composite resins we used in our study; it was observed that the coloration increased as the residence time in the solution increased.

Change in surface properties of two different dental resin composites after using various beverages and brushing

BackgroundThe study aimed to evaluate the influence of various beverages; with and without brushing; on the surface mechanical properties of two resin composites.MethodsA total of 160 disc-shaped specimens were prepared for each of the following dental composites; nanohybrid ormocer (Admira fusion, VOCO GmbH, Cuxhaven, Germany) and nanohybrid resin composite (Grandio, VOCO GmbH, Cuxhaven, Germany). The baseline surface hardness and roughness measurements were carried out after 24 h. The composite samples were randomly distributed into one of the two groups; brushing and non-brushing, which were further divided into one of the four subgroups (n = 10); artificial saliva as control, coffee, red wine, and soft drink. In the non-brushing group, the specimens were immersed in the different beverages for five minutes three times daily for 30 days. The same procedure was done for the brushing group, in addition to brushing the specimens for five seconds. The surface hardness and roughness measurements were repeated after 30 days. One-way ANOVA and independent t-tests were used for statistical analysis.ResultsThe soft drink had the most deteriorating effect and artificial saliva had the least. The change in surface properties was higher in the brushing subgroups. Grandio exhibited a higher change in surface microhardness while Admira fusion exhibited a higher change in surface roughness.ConclusionsThe surface properties of both dental resin composites were negatively affected by using beverages and brushing.

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.

Effect of Commercial Mouth Rinses on Physical Properties of Conventional and Bulk-fill Resin Composites.

To evaluate the effects of commercial mouth rinses on color, roughness, sorption (SR), and solubility (SL) of resin composites. Disc-shaped specimens (stage I: 6 mm × 2 mm; stage II: 10 mm × 1.5 mm) were made from the following resin composites (n=10): conventional nanofilled (Filtek Z350XT, 3M Oral Care), conventional nanohybrid (Luna, SDI), bulk-fill nanofilled (Filtek One Bulk-Fill, 3M Oral Care), and bulk-fill nanohybrid (Aura Bulk-Fill, SDI) exposed to distilled water (control), blue mouth rinse without alcohol (Colgate Total 12 Clean Mint, Colgate-Palmolive), or blue mouth rinse with alcohol and essential oil (Listerine Tartar Control, Johnson & Johnson). In stage I, tests were performed at the baseline, and after the immersion in solution time points to evaluate coordinates of the CIEL*a*b* system (ΔL*, Δa*, Δb*), general color change (ΔEab, ΔE00, and ΔSGU), and surface roughness (Ra). In stage II, SR and SL were evaluated (ISO 4049:2019) after immersion in the solutions for 7 days. The results were evaluated by generalized linear models (Ra, SR), Kruskal-Wallis, and Dunn tests (color, SL), with α = 0.05. There were no significative differences for Ra between the solutions. Both mouth rinses promoted significantly negative ΔL* (Luna), Δa* (Filtek One Bulk-fill), and Δb* (all materials except conventional nanofilled resin composite). Mouth rinse without alcohol promoted significantly negative Δa* on all resin composites tested. Both mouth rinses promoted higher ΔEab and ΔE00 for bulk-fill resin composites compared to control. Mouth rinse with alcohol caused higher ΔSGU for bulk-fill nanofilled resin composite. It also promoted greater SR in all the resin composites compared with mouth rinse without alcohol and higher SR in nanohybrid resin composites compared with control. Both mouth rinses promoted higher SL values in Luna and differed significantly from control. The physical properties were manufacturer dependent and mediated by mouth rinses. The mouth rinses promoted color changes in the resin composites, pointing out that bulk-fill resin composites were more affected by these effects, especially when the mouth rinse contained essential oil and alcohol.

Effect of Aging and Different Surface Treatments on Repair Bond Strength of Hybrid Resin Composites

Background: With the trend for minimally invasive dentistry and the rapid evolution of composite resin materials, repair of defective composite resin restorations is a popular choice rather than replacement of the restoration. The durability of the bond between the old and repaired composite restoration is important for a successful outcome. Objective: To evaluate the immediate and delayed shear bond strength of two types of repaired hybrid resin composites using different chemical and mechanical surface treatments. Methods: Two types of hybrid resin composites, micro-hybrid resin composite and nanohybrid resin composite, were used to prepare 288 pre-polymerized resin composite specimens. After polymerization, repair was done after 24 hours and 6 months. Each hybrid resin composite group was divided into 3 groups according to surface treatment used to repair the substrate: group 1: no surface treatment, group 2: treated by medium abrasive stone, and group 3: treated by fine abrasive stone. Each group was further subdivided into 3 subgroups according to different agents used for repair: group 1: Silane, group 2: Universal adhesive, and group 3: Silane + adhesive. Shear bond strengths of the repaired specimens were measured using a Universal testing machine. Failure modes were evaluated under a stereomicroscope. Results: Different chemical and mechanical surface treatments had a significant effect on the shear bond strength values of all groups (p ≤ 0.05). The highest mean shear bond strength values were found in nano-hybrid composites immediately repaired by silane after treatment by a medium abrasive stone while the lowest mean shear bond strength values were found in micro-hybrid composites with delayed repair and no surface treatment. Conclusion: Diamond burs using silane with adhesive improved the repair bond strength of the tested hybrid composites. In composite repair, using abrasive mechanical pretreatment followed by adhesive conditioning is crucial for the success of the repair restoration.

An In Vitro Comparison of Shear Bond Strength for Heated Composite Resin With Three Conventional Luting Cements.

Forty-eight lithium disilicate disc samples are collected and put on acrylic blocks for this investigation. To improve luting cement adhesion, the discs are etched with 5% hydrofluoric acid (HF) gel. For easier handling and lower viscosity during luting, the composite resin is heated to between 55 and 68°C on a digital wax melter. Shear bond strength tests were executed with the universal testing device after the following luting cement was applied in the center of the test specimen (lithium disilicate discs). Statistics software was used for the calculations and analysis. In accordance with the findings of the tests, shear bond strengths ranged from 2.2851 ± 0.5901 for nanohybrid composite resin to 7.3740 ±0.6969 for self-adhesive resin cement and 4.4647 ± 0.9774 for light-activated resin cement. A statistically significant (p≤0.001) difference between the groups was found. Mean shear bond strength was significantly highest in the self-adhesive resin cement group, followed by the light-activated resin cement group, resin-modified GIC, and least with the nanohybrid composite resin group. Composite resins; in fixation of indirect restorations can have their viscosity reduced by preheating in a device, but they must be employed as soon as possible after removal.Standardizing the methods of heating composite resins for cementation is necessary to achieve desirable outcomes and direct the physician in their application. Although preheating composite resins for luting operations can be utilized to decrease the material's viscosity and enhance the restoration setting; it may not increase bond strength.

Mechanical properties of 3D-printed and milled composite resins for definitive restorations: An in vitro comparison of initial strength and fatigue behavior.

To evaluate the flexural strength and fatigue behavior of a novel 3D-printed composite resin for definitive restorations. Fifty disc-shaped specimens were manufactured from each of a nanohybrid composite resin (NHC), polymer-infiltrated ceramic network (PICN), and 3D-printed composite resin (3D) with CAD-CAM technology. Biaxial flexural strength (σin ) (n = 30 per group) and biaxial flexural fatigue strength (σff ) (n = 20 per group) were measured using piston-on-three-balls method, employing a staircase approach of 105 cycles. Weibull statistics, relative-strength degradation calculations, and fractography were performed. The results were analyzed with 1-way ANOVA and Games-Howell post hoc test (α = 0.05). Significant differences in σin and σff among the groups (p < 0.001) were detected. The NHC group provided the highest mean ± standard deviation σin and σff (237.3 ± 31.6 MPa and 141.3 ± 3.8 MPa), followed by the PICN (140.3 ± 12.9 MPa and 73.5 ± 9.9 MPa) and the 3D (83.6 ± 18.5 MPa and 37.4 ± 23.8 MPa) groups. The 3D group exhibited significantly lower Weibull modulus (m = 4.7) and up to 15% higher relative strength degradation with areas of nonhomogeneous microstructure as possible fracture origins. The 3D-printed composite resin exhibited the lowest mechanical properties, where areas of nonhomogeneous microstructure developed during the mixing procedure served as potential fracture origins. The clinical indications of the investigated novel 3D-printed composite resin should be limited to long-term provisional restorations. A cautious procedure for mixing the components is crucial before the 3D-printing process, since nonhomogeneous areas developed during the mixing could act as fracture origins.

Performance of direct and indirect onlay restorations for structurally compromised teeth

Research is lacking on the restoration of structurally compromised posterior teeth using direct composite resin or indirect restorations. The purpose of this in vitro study was to measure the fracture resistance and microleakage of different onlay restorations fabricated by using conventional and digital computer-aided design and computer-aided manufacturing (CAD-CAM) to restore structurally compromised teeth. Mandibular molars (n=54) were prepared for onlay restorations. Teeth were allocated to 3 groups (n=18) according to the type of restoration materials, nanohybrid composite resin (Grandio blocs), resin hybrid ceramic (SHOFU Block HC), and fiber-reinforced composite resin (everX Posterior). Onlays were bonded using a dual-polymerized adhesive resin cement. All specimens were thermocycled, followed by cyclic loading. Based on the type of investigation conducted, fracture resistance, and microleakage test, each group was then divided into 2 equal subgroups (n=9). The collected data were statistically analyzed with the chi-square of the Fischer exact test (α=.05). Fracture resistance testing revealed a statistically significant difference between groups (P<.001). The fiber-reinforced composite resin demonstrated the highest fracture resistance, with statistically significantly less microleakage compared with the other groups (P=.013). Direct fiber-reinforced composite resin could be considered a suitable alternative to CAD-CAM composite resin for the restoration of structurally compromised teeth.

Effect of a Diode Laser (445 nm) on Polymerization Efficiency of a Preheated Resin Composite Used for Luting of Indirect Composite Restorations.

The aim of this study was to evaluate the polymerization efficiency of a preheated resin composite used as a luting agent for indirect restorations light-cured by a blue diode laser (445 nm). Bronze molds were used to prepare cylindrical specimens of a laboratory composite (Ceramage) with dimensions 2, 3, and 4 mm in height and 8 mm in diameter. The molds had additional height of 120 μm for the placement of the preheated resin composite. A nanohybrid resin composite (Enamel Plus HRi) was preheated at 55°C to use as a luting agent. Photopolymerization was followed for 20 seconds using three light sources: a diode laser emitting at 445 nm (SiroLaser Blue) and two light-emitting diode (LED) units (Bluephase Style and Valo). Degree of conversion (DC) of the preheated resin composite was evaluated using Fourier transform infrared spectroscopy. The results indicated that the main effects of the analysis were significant for both material thickness (p<0.001) and polymerization method (p<0.001). The preheated resin composite was not polymerized under 4-mm-thick specimens, independent of the light-curing unit. For 2-mm material thickness, there was no difference among the three light-curing units (p=0.383), while 3-mm Bluephase Style presented very low DC. Diode laser (445 nm) achieved better polymerization efficiency at the same fluence compared to the LED unit at 3-mm depth, implying a better mechanical behavior and potential improved adhesion of the luting material to dentin.

Two-year clinical evaluation of Class I composite resin restorations using three adhesive systems: A double-blind randomized clinical trial

Aim: The purpose of this randomized split-mouth clinical study was to assess the effect of three adhesive systems on the 2-year clinical success of Class I composite resin restorations. Methodology: In the treatment of the Class I carious lesions of 20 participants aged 18–24 years with at least three similar carious lesions, three adhesives—Clearfil SE Bond (CSE; Kuraray, Osaka, Japan), Single Bond 2 (SB2; 3M ESPE, St. Paul, MN, USA), and Tri-S Bond (TSB; Kuraray, Osaka, Japan)—and a Filtek Z550 nanohybrid composite resin (3M ESPE, St. Paul, MN, USA) were cured. The baseline and 2-year results of the restorations were assessed according to the World Dental Federation (FDI) and the United States Public Health Service (USPHS) criteria. The chi-square test was used to analyze the data obtained. Results: There was no loss of restoration in any group at 2 years. No significant differences were observed in any criteria (marginal staining, fracture retention, secondary caries, and postoperative sensitivity) evaluated except marginal adaptation, in accordance with FDI and USPHS criteria (p &gt; 0.05). At 2 years, SB2 showed the best marginal adaptation, followed by CSE and TBS. There was a statistically significant difference between SB2 and TSB (p ˂ 0.05). Conclusion: All three adhesive systems can be used successfully in the restoration of Class I carious lesions. How to cite this article: Çakır Kılınç NN, Demirbuğa S. Two-year clinical evaluation of Class I composite resin restorations using three adhesive systems: A double-blind randomized clinical trial. Int Dent Res 2023;13(2):67-74. https://doi.org/10.5577/idr.2023.vol13.no2.4 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

A Comparative Study of the Repair Bond Strength of New Self-Adhesive Restorative Materials With a Resin Composite Material.

The aim of the present study is to compare the repair bond strengths (RBSs) of Cention-N (light-cure and self-cure modes), Equia Forte HT Filand a nanohybrid resin composite. Equia Forte HT Fil (GC, Tokyo, Japan), Cention-N (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Z550 (3M ESPE, St Paul, MN, USA) were used in this study.EquiaForte HT Fil(EQF), Cention-N self-cure (CSC), Cention-N light-cure (CLC) and Filtek Z550 (Z550) groups were formed.A total of 40 samples were prepared; 10 samples in each group (n = 10).After the polymerization was completed according to the manufacturer's instructions, the samples were polished with OptiDisc (Kerr Corporation, Orange, USA) for 5 s each, from extra-course to extra-fine. After all samples were stored in 37°C water for 24 h, 10,000 cycles of brushing simulator and thermal cycles were applied to the samples.The samples were prepared in accordance with the selected repair protocol, and microshear bond strength (µSBS) test was performed. Fracture analysis on debonded surfaces was visualized by scanning electron microscopy. The conformity of the data to normal distribution was analyzed by the Shapiro-Wilk test. Multiple comparisons were performed using Dunn's test. Z550 showed significantly higher µSBS as compared to the other three groups. There is no differencebetween CSC, CLC and EQF. The use of Cention-N's self-cure or light-cure mode did not affect the RBSvalues. The RBS values of Cention-N and Equia Forte HT Fil materials are lower than those of the composite resin material.

Effect of Lemon Juice, Apple Cider Vinegar and Green Tea on Microhardness of Nanohybrid resin composite: An In-vitro study

This study aimed to evaluate effect of Lemon Juice, Apple Cider Vinegar and Green Tea on microhardness of nanohybrid resin composite using vickers microhardness tester. Materials and methodology: Forty specimens of nanohybrid resin composite (3M ESPE Filtek Z350 XT) were prepared and polished the prepared discs using sandpaper. Before immersion of prepared composite discs in prepared solutions the baseline data of microhardness of each prepared composite discs were recorded by using Vicker’s microhardness tester. The prepared composite discs were divided into 4 groups (n=10) and alternatively immersed in 25 ml of prepared solutions namely Green tea, Apple Cider Vinegar, Lemon Juice and Artificial saliva for 5 sec and then in 25 ml of artificial saliva for another 5 sec and the procedure was repeated for 10 cycles. After following the above mentioned procedure, artificial saliva was used as storage media for 24 hours. For the next 28 days, this entire process was repeated. The microhardness test was carried out prior to immersion and then at intervals of 7, 14, 21 &amp; 28 days after immersion in respective solutions. Results: Two-way analysis of variance (ANOVA) with repeated measurements was carried out for the obtained data. Artificial Saliva demonstrated highest microhardness values at all time points, followed by Green Tea and Lemon Juice. Apple Cider Vinegar showed the least microhardness values of all the four groups tested. Conclusion: All the beverages significantly reduced surface microhardness of nanohybrid resin composite, especially at the end of 28 days. Immersion in apple cider vinegar caused more reduction in surface hardness over time when compared to other beverages. The outcome on microhardness of nanohybrid resin composite by these beverages on depended upon time the latter was exposed and also the chemical composition of beverages. Keywords: Apple Cider Vinegar, Green Tea, Lemon Juice, Microhardness, Nanohybrid resin composite, Vickers Microhardness Tester

In Vitro evaluation of the effects of whitening toothpastes on the color and surface roughness of different composite resin materials

BackgroundThe aim of this study was to evaluate the effects of traditional and whitening toothpastes on the color and surface roughness of different composite resin materials.MethodsEighty disc-shaped samples were prepared for each of the following composite resins: nano-hybrid (Filtek Ultimate Universal; 3 M/ESPE, Saint Paul, USA), micro-hybrid (Charisma Smart; Kulzer, Hanau, Germany) and supra-nano-filled (Omnichroma; Tokuyama, Tokyo, Japan). Each composite-resin sample was randomly divided into the following four subgroups (n = 20 per group): Group 1, control; Group 2, traditional toothpaste (Colgate Total 12; Colgate Palmolive, New York, USA); Group 3, peroxide-based toothpaste (Colgate Optic White; Colgate-Palmolive, New York, USA); and Group 4, blue covarine-based toothpaste (Meridol Gentle White; CP-GABA, Hamburg, Germany). The samples for the toothpaste subgroups were immersed in a coffee solution for 10 min and washed twice a day before each brushing cycle. The specimens were brushed for 30 days. Color analyses were performed using a spectrophotometer (SpectroShade Micro, MHT, Italy). Surface roughness analyses were conducted using a profilometer (Surftest SJ-210 Mitutoyo, Tokyo, Japon). The color and surface roughness analyses were performed at baseline and 1, 7 and 30 days after each treatment. Furthermore, surface topography analysis was performed using Scanning Electron Microscopy (FEG 250-FeiQuanta, the Netherlands). The data were analysed with a three-way robust ANOVA and Bonferroni post-hoc correction (p < 0.05).ResultsThe smallest color change was observed for the micro-hybrid composite resin, and the greatest color change was observed for the nano-hybrid composite resin. Based on the tested composite resin samples, the greatest color change was obtained after using blue covarine–based toothpaste, while the smallest color change was observed after using peroxide-based toothpaste. Moreover, the supra-nano-filled composite resin samples exhibited the lowest roughness values (robust ANOVA test, p < 0.001). There was no statistically significant difference between the mean values of roughness for the composite, group and time interaction (p = 0.937).ConclusionCharisma Smart composite resin exhibited significantly lower staining than all the other composite resins tested after using all toothpastes included in the study. Further laboratory and clinical studies are needed to fully understand the long-term effectiveness of whitening toothpaste on composite resin materials.

The effect of imposing apple (Malussylvestris Mill) juice on discoloration of nanofiller and nanohybrid composites

Composite resin can undergo discolouration if exposed to dyes. The use of apples can whiten teeth because they contain ma-lic acid. True experiment research with pretest-posttest with control group design using 24 samples divided into 6 treatments, namely sample groups 1 and 2 (nanofiller and nanohybrid composite groups that have been discoloured soaked in apple fruit juice (Malus sylvestris Mill) 80% concentration, groups 3 and 4 (negative control group, discoloured nanofiller and nanohy-brid composites soaked in distilled water) and groups 5 and 6 (positive control group, discoloured nanofiller and nanohybrid composites soaked in 10% carbamide peroxide). The colour change was determined with a shade guide (Vitapan Classical). The results were normally distributed and homogeneous. One-way Anova test showed there was a significant difference in each group. In the independent t-test, there was a significant difference in colour change between nanofiller and nanohybrid composite resins that experienced discoloration in 80% apple juice immersion. It was concluded that nanofiller composite resin had lower discolouration compared to nanohybrid.

Evaluation of mechanical properties of different polyetheretherketone endodontic post systems: an in vitro study

BackgroundSurvival of endodontically treated teeth depends on an efficient restoration of the missing tooth structure.ObjectivesThis study aimed to investigate the mechanical properties of different endodontic post systems.Materials and methodsHuman permanent maxillary central incisors (no.=58) were decoronated and root-filled. The specimens with prepared root canals were randomly divided into Group P: Polyether Ether Ketone (PEEK) post and composite core and Group C: custom-made post-core of PEEK. The cementation of the posts was carried out using self-adhesive resin cement. Nano-hybrid composite resin was used for core fabrication. After cementation, the specimens from each group were randomly divided into two subgroups according to the types of tests utilized: 14 from each group were for the fracture strength test, which was restored with IPS e-max CAD crown, and 15 from each group for the pullout resistance test. A universal testing machine was used for the test performance.ResultsThe fracture resistance test showed that the values significantly differed among tested posts (P = 0.013). Group P showed the highest fracture resistance. Group C exhibited higher mean pullout resistance values than the other group (P) (P = 0.059). In the two-piece PEEK post and composite core, the predominant type of failure was a core fracture, while in the one-piece PEEK post-core, most types of failures were either in the crown or in the post.ConclusionsThe prefabricated posts are more resistant to fracture than the custom-made posts, with fracture and displacement mainly of the core. In contrast, both showed similar pullout resistance.

Compressive strength of nanohybrid composite resin after the application of glycerin immersed in fermented milk

Background: The prevalence of dental caries in Indonesia in 2018 is 45.3% of the population. Tooth filling is done so that dental caries does not spread further. The restorative material that is commonly used is composite resin. The compressive strength of composite resin is affected by the polymerization process. The surface of the composite resin exposed to air causes the formation of oxygen inhibited layer (OIL). Glycerin acts as a surface coating that can inhibit contact between the composite resin and air so that polymerization can run optimally. Changes in the mechanical properties of composite resins are also influenced by salivary pH and food intake. The acid contained in fermented milk can affect the matrix and filler bonds in composite resins. Further research is needed to determine the compressive strength of nanohybrid composite resins after the application of glycerin in fermented milk immersion. Purpose: To find out whether there is a change in the compressive strength of nanohybrid composite resin after the application of glycerin immersed in fermented milk, also to find out whether the glycerin application and immersion in fermented milk play a role in causing changes of the compressive strength. Methods: Laboratory experimental research with a total sample of 28 which was divided into 4 groups. Composite resin samples were made with a thickness of 3 mm and a diameter of 5 mm, followed by measuring the compressive strength using the Universal Testing Machine. Results: Independent T-Test test showed significantly different results. The compressive strength value of the group with glycerin application was higher than without glycerin application. Meanwhile, the group immersed in fermented milk drinks had lower compressive strength compared to saline immersion. Conclusion: The compressive strength of the nanohybrid composite resin changed after the application of glycerin immersed in fermented milk.

Effect of Laser and Conventional Office Bleaching and Polishing on the Color Change of Stained Nanohybrid and Microhybrid Composite Resin.

The present study investigated the effects of laser and conventional in-office bleaching, and polishing on the color of stained composite resin. A microhybrid composite (Clearfil AP-X) and a nanohybrid composite (Grandio) were selected. Twenty-four discs (2 × 10 mm) for each composite were prepared. The samples were immersed in coffee solution (25 g of coffee in 250 mL water) for seven days. Then the samples were divided into three groups (n = 8) and the stains were removed using bleaching (with Opalescence Xtra Boost), diode laser irradiation with Heydent material and a Sof-Lex polishing kit. The L ∗a ∗b ∗ color parameters were determined using a spectrophotometer before and after immersion and after stain removal procedures, and the overall color changes (ΔE) were calculated. The data were analyzed with two-way analysis of variance. In the Clearfil composite resin group, the mean ΔE compared to the baseline using in-office bleaching, laser irradiation, and Sof-Lex polishing kit were 3.31, 3.35, and 4.93, respectively. These values with the Grandio composite resin were 3.31, 6.35, and 4.57, respectively. The highest capacity to remove stains was related to the conventional in-office bleaching method. Grandio composite resin underwent more color changes than Clearfil composite resin significantly (P-value < 0.05). Both composite resins exhibited color changes after immersion in the discoloring solution. However, after staining-removing procedures, the ΔE values decreased. Decreases in the ΔE values were not sufficient to restore the color to that before immersion in the discoloring solution with any stain-removing methods.

Wear resistance of CAD/CAM one-piece screw-retained hybrid-abutment-crowns made from different restorative materials.

The aim of this study was to measure the wear progress of three high performance polymers (HPP) materials as well as that of zirconia after artificial aging (simulated 2.5- and 5-year of clinical service with thermo-mechanical loading) and compare it with the well-documented wear of lithium disilicate. Forty implants were used to restore a maxillary first premolar, where the abutment and the crown were manufactured as hybrid-abutment-crown and connected to the implant using a titanium insert. The implants were randomly divided, according to the restorative materials used, into five groups: 3Y-TZP zirconia (Z), lithium disilicate (L), ceramic-reinforced polyetheretherketon (P), nano-hybrid composite resin (C) and polymer-infiltrated ceramic-network (E). All hybrid-abutment-crowns were produced using CAD/CAM technology. A design of a maxillary first premolar was created with an angle of 120° between the buccal and palatal cusps, which were designed as planes. The restorations were adhesively luted onto the titanium inserts, according to the manufacturers' recommendations for each material individually, by means of dual-curing luting resin with the exception of group P, where the blocks were pre-fitted (heat-pressed) with an integrated titanium insert. The suprastructures were assembled onto the implants through titanium screws. The screw channels were sealed with Teflon tape and composite resin filling material that was polished to high-gloss. All specimens underwent 1 200 000 thermo-dynamic loading cycles with 49 N in a dual-axis chewing simulator. Elastomeric impressions were made for all specimens after 600 000 and after 1 200 000 cycles. The corresponding impressions were imaged using a laser scanning microscope and then 3D-analyzed using the software (Geomagic Wrap) to measure the volume loss of the wear area for all specimens. Statistical analysis was performed using Wilcoxon-Test regarding the two different time measurements for each material. For the analysis of the material variable, Kruskal-Wallis test was conducted followed by Mann-Whitney test. Group Z showed statistically the lowest volume loss compared to the other test materials, both after 600 000 and 1 200 000 cycles of artificial aging, with a median value of 0.002 mm3 volume loss after 1 200 000 cycles. In contrast, group E showed the highest volume loss with median values of 0.18 and 0.3 mm3 after 600 000 and 1 200 000 cycles, respectively. Artificial aging had significantly negative effect on the volume loss for all test materials. In addition, the choice of material had statistical influence on the outcome. Monolithic zirconia ceramic demonstrated lower wear than that reported for enamel after simulated 5-year of clinical service, whereas all other test materials showed higher volume loss after artificial aging.

One step polishing to compare the mean surface roughness of nanohybrid and microhybrid composite resins

Objectives: This study's goal was to compare the mean surface roughness of nano hybrid and micro hybrid composites using a one-step polishing method. This comparison was made based on the idea that a material with reduced surface roughness will exhibit superior perishability, aesthetics, surface &amp; optical properties, which means less wear, less staining, low plaque, and low caries rate. Methodology: This comparative study was carried out in April 2023 at the Ayub Medical College in Abbottabad, Pakistan, with a sample size of 100 (50 in each group), determined by the WHO calculator. Using a mechanical stainless steel template, 120 composite resin specimens mounted on acrylic blocks with dimensions of 2 mm x 3 mm x 3 mm were created. Results: 100 samples, separated into two groups, were used in this study. According to descriptive statistics, mean surface roughness and standard deviations for Nano hybrid composite in Group A were recorded as 0.076+0.025 and for Micro hybrid composite in Group B, they were 0.001+0.036. Conclusion: After polishing with a one-step procedure, there is a noticeable difference between the surface roughness of nano hybrid and micro hybrid composite resins, indicating that the former has higher polish ability than the latter.