Composite Resin Core Material Research Articles

Evaluation of Micro-Tensile Bond Strength of Fibre Post with Titanium Dioxide Nanoparticles as Fillers in Experimental Dental Composite Resin.

Background: The clinical success of post-core restorations is determined by the composite utilized and the strength of the post-core adhesion. The effectiveness of titanium dioxide nanoparticles (TiO2 NPs) as a multifunctional material with photo-induced activities and better mechanical characteristics are observed as particle size is reduced to under 50 nm. Aim: The purpose of this study is to determine the bond strength of fibre-reinforced composite (FRC) posts with TiO2 NP as fillers and to compare it with conventional composite resin core material. Materials and Methods: 30 single-rooted mandibular premolars were selected and routine root canal procedures were done. A quantity of 5% TiO2 NPs were synthesized and added as silanized filler to the experimental composite resin. Post space was prepared and fibre-reinforced composite (FRC) post luting was performed. The specimens were then grouped into the following groups: Group I consisted of the experimental composite resin containing 5% TiO2 fillers, Group II consisted of core X flow, and Group III consisted of Multicore Flow. All test groups were submitted for thermocycling. After this, the samples were tested for micro tensile bond strength. A stereomicroscope with a magnification of 20× was used to examine the fractured surfaces. The data were analysed using one-way ANOVA and Tukey HSD tests. Results: Statistical analysis revealed that Group I showed the highest mean bond strength value of 35.6180 Mpa. The results obtained with Group III showed the lowest mean bond strength value of 19.4690 Mpa. Adhesive failures were identified by stereomicroscopy of the fractured surfaces. Conclusion: The experimental composite resin comprising 5% TiO2 NP had a greater bond to the FRC post than other materials tested.

Effect of surface treatment on bond strength between zirconia and composite resin core material

Effect of surface treatment on bond strength between zirconia and composite resin core material

Development of dental inspection method: Nondestructive evaluation of an adhesive interface by ACTIVE acoustic emission.

This study aims to confirm the usefulness of active acoustic emission (Active AE) for reproducible and non-invasive generation of physical external force which is required for conventional AE. Experiment 1: A root dentin-resin adhesive interface was observed. The post space was filled with a dual-cure resin composite core material with and without adhesive. The vibration characteristics of the data obtained from the time-frequency analysis were evaluated. Experiment 2: A crown-abutment tooth adhesive interface was observed. Adhesive resin cement was used for luting the crown and adhesion states in the same specimen over time were analyzed with three measurements: at trial-fitting, immediately after luting, and 2 weeks after luting. Data were subjected to time-frequency analysis and relationships between amplitude (indicating loudness) and frequency (indicating the sound component) were analyzed. Experiment 1: Time-frequency analysis confirmed multiple peak frequencies for each specimen without adhesive and monomodal peak frequency in all specimens using adhesive. Experiment 2: Two weeks after luting, all specimens showed a single major peak except one which showed multiple weak peaks. The three-dimensional visualization of time-frequency analysis revealed one specimen with multiple weak peaks while all others displayed a single, low-amplitude band at 2 weeks after luting. The state of the adhesive interface can be evaluated using active AE. This basic technique may prove useful to evaluate changes in the adhesive interface of prostheses over time.

24 hour polymerization shrinkage of resin composite core materials.

The study's purpose was to evaluate the 24-hour polymerization shrinkage of resin composite core materials. Eleven resin composite core material samples (n= 12) were evaluated using a non-contact imaging device with measurements obtained over 24 h. Shrinkage values were determined corresponding to proposed times involved with CAD/CAM same-day treatment and at 24 h. Shrinkage data was statistically compared using Friedman/Dunn's test for intragroup analysis and Kruskal Wallis/Dunn's test for intergroup analysis, all at a 95% level of confidence (α=0.05). Mean results identified a wide volumetric shrinkage range with considerable similarity overlap. Inconsistent shrinkage behavior was evident and all materials reached maximum values before 24 h. No significant difference was observed during proposed digital same day all ceramic crown procedures, but some differences were noted at 24 h. Under this study's conditions results were material specific, at times inconsistent, with wide variation. Shrinkage consistently increased for all products and it is not known if the continued shrinkage magnitude may compromise the stability and fit of all-ceramic crowns at 24 h.

Development of dental inspection method: nondestructive evaluation of a dentin-adhesive interface by acoustic emission.

Purpose The state of adhesion between root dentin and a resin composite core material was inspected using acoustic emission (AE).Methods A total of 14 human incisors and premolars were used to prepare "no-adhesive group" and "adhesive group" specimens. For "adhesive group" specimens, a bonding agent was applied to root canal dentin. The entire post space was subsequently filled with a resin composite for both specimen groups. The prepared specimens were fixed onto a jig on which an AE sensor was installed. A zirconia ball was used for the impact test, and a vibration wave generated by the collision was measured by the system using an AE sensor. The obtained data were subjected to time-frequency analysis using analysis software (LabVIEW), and the relationship between the amplitude indicating the loudness and the frequency indicating the sound component was analyzed.Results Zirconia-ball collision tests using AE revealed differences between the groups with respect to the waveform of vibration waves transmitted to the root dentin through the root dentin-resin interface. The time-frequency analysis of the obtained data confirmed that multiple peaks were observed for each specimen in the no-adhesive group, whereas a single characteristic vibration peak was observed for all specimens in the adhesive group.Conclusions The state of the adhesive interface was successfully evaluated by AE. This demonstration is expected to lead to the development of a device that can detect problems at the bonding interface between the prostheses and tooth substances.

Effect of surface treatment of CAD/CAM resin composites on the shear bond strength of self-adhesive resin cement.

This study examined the effects of sandblasting, hydrofluoric acid etching and priming on the shear bond strength of self-adhesive resin cement between seven different CAD/CAM resin composites and a resin composite core material at 24-h after cement mixing. Five surface treatments [control (C), sandblasting (S), priming (P), sandblasting with priming (SP), and 9% HF etching with priming (HFP)] were performed respectively for disc specimens of CAD/CAM blocks. There were no significant differences in bond strength among the C, S, and P, except for one block (p>0.05). SP showed a greater bond strength than S. Weibull moduli were not changed significantly among all treatments for all blocks, whereas the strengths with 5% and 95% failure probability of SP and HFP showed greater values than the others. The bond strengths of HFP were comparable to those of SP. Priming after sandblasting or HF etching could be effective to increase the bond strength of CAD/CAM blocks.

Effect of different surface treatments of human occlusal sclerotic dentin on micro-tensile bond strength to resin composite core material.

The objectives of this study were to evaluate the micro-tensile bond strength (μTBS) of composite bonded to human occlusal sclerotic dentin following different surface treatments to determine the sclerotic dentin morphology. Human molars without (normal dentin; group 1) or with occlusal wear (sclerotic dentin; groups 2-5) were divided and subjected to different surface treatments, including the normal protocol for the Contax self-etch bonding system (group 1 and 2); doubled etch-prime time (group 3); pre-conditioning with 37% phosphoric acid before normal protocol (group 4); or pre-conditioning with 37% phosphoric acid before doubling the self-etching time (group 5). All teeth were restored with composite (Luxacore Z dual), sectioned into stick specimens and stored for 24h in water before specimens were subjected to the μTBS test (n=50 per group). The μTBS of normal dentin was not statistically significantly different from that of the sclerotic dentin groups, except for the doubled etch-prime time group which showed lower μTBS. Sclerotic dentin pre-treated with phosphoric acid resulted in less sclerotic casts and wider dentinal tubules, while doubled etch-prime time did not alter the morphology, as shown by scanning electron microscopy. In conclusion, the use of 37% phosphoric acid before applying self-etch bonding resulted in more tubule openings and a significantly higher μTBS when compared with the doubled etch-prime time group.

Microtomographic Analysis of Resin Composite Core Material Porosity.

To nondestructively evaluate the porosity of ten contemporary resin composite core materials using microtomographic (microCT) analysis. Resin composite core material samples (n = 12) including dual-cure, visible light cure only, and a self-cure material were fabricated using a standardized mold following manufacturer's recommendations. After storage in phosphate buffered saline for one week, specimens were analyzed using a microCT unit at 5.3-µm resolution over a rotational range of 360°. Image 3D recombination and analysis was accomplished using microCT software. Evaluated parameters included material volume investigated, closed pore number and volume, as well as closed pore percentage. Parameter mean values were evaluated with Kruskal-Wallis/Dunn at a 95% confidence level (α = 0.05). Mean percent total porosity with standard deviation identified significant differences in decreasing order as Ti-Core: 2.2 (0.4) > Ti-Core Auto E: 1.3 (0.3) = Ti-Core Flow Plus: 1.1 (0.02) > Clearfil Photo Core: 0.94 (0.5) = Clearfil DC Core Plus: 0.6 (0.18) = MultiCore Flow: 0.58 (0.1) > Fluorocore 2+: 0.14 (0.2) = Build-It FR: 0.068 (0.02) = Gradia Core: 0.03 (0.02) = Rebilda DC: 0.02 (0.01). A pilot microCT evaluation evaluating a mixing tip revealed incomplete mixture between the two resins with porosity introduced from turbulence as the materials are forced through the tip during preparation. A wide range of porosity was identified between the ten materials evaluated. These preliminary results warrant more investigation evaluating additional resin composite core materials, the preparation capabilities of automix tips, and porosity presence in the unmixed materials.

Impact of different surface treatment methods on bond strength between fiber post and composite core material

PurposeTo assess the impact of different surface treatments on the push-out bond strength between fiber post and a composite resin core material. Material and methodsSeventy-two glass-fiber posts were randomly assigned into six groups according to the method of surface treatment: Control (no treatment), silane, sandblasting, hydrofluoric acid, hydrogen peroxide, and hydrogen peroxide with sandblasting. Two posts from each group were inspected under a scanning electron microscope to assess the surface modifications and 10 posts were employed for the push-out test. Each post was placed vertically in the middle of a cylindrical putty matrix and a dual-cure composite resin material was applied for core build-up. Two discs of each specimen were cut using a low-speed diamond saw (total 120 discs). The push-out test was executed using a universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analysis was performed using one-way ANOVA and Tukey’s test (p ≤ 0.05). The mode of failure of each disc was evaluated under SEM. ResultsThe sandblasting and hydrofluoric acid groups presented significantly higher bond strength than control and hydrogen peroxide groups. The hydrogen peroxide groups exhibited significantly the lowest bond strength of all groups. There was no significant difference between the control and silane groups. All groups showed predominantly adhesive failure except the hydrogen peroxide with sandblasting, where the cohesive failure of the post was predominant. ConclusionsSandblasting and hydrofluoric acid surface treatments demonstrated superior results to silane and hydrogen peroxide. The combined method of hydrogen peroxide and sandblasting could weaken the fiber post and lead to clinical fractures.

Endodontic Access Effect on Full Contour Zirconia and Lithium Disilicate Failure Resistance.

To evaluate the effect of endodontic access on the failure load resistance of both adhesively and conventionally luted, full-contour monolithic yttria-stabilized zirconium dioxide (Y-TZP) and adhesively luted lithium disilicate (LD) crowns cemented on prepared teeth. Seventy-two human maxillary molars were prepared per respective guidelines for all-ceramic crowns with one group (n=24) restored with LD and the other (n=48) receiving Y-TZP crowns. Preparations were scanned using computer-aided design/computer-aided milling (CAD/CAM) technology, and milled crowns were sintered following manufacturer recommendations. All LD crowns and half (n=24) of the Y-TZP crowns were adhesively cemented, while the remaining Y-TZP specimens were luted using a conventional glass ionomer cement (GIC). One LD group, one Y-TZP adhesive group, and one GIC-luted group (all n=12) then received endodontic access preparations by a board-certified endodontist: the pulp chambers were restored with a dual-cure, two-step, self-etch adhesive and a dual-cure resin composite core material. The access preparations were restored using a nano-hybrid resin composite after appropriate ceramic margin surface preparation. After 24 hours, all specimens were loaded axially until failure; mean failure loads were analyzed using Mann-Whitney U test (α=0.05). Endodontic access did not significantly reduce the failure load of adhesively luted LD or Y-TZP crowns, but Y-TZP crowns with GIC cementation demonstrated significantly less failure load. These initial findings suggest that endodontic access preparation may not significantly affect failure load resistance of adhesively luted Y-TZP and LD crowns. Definitive recommendations cannot be proposed until fatigue testing and coronal seal evaluations have been accomplished.

An evaluation of the effect of the chemical and mechanical surface treatment of the glass fibre posts on the retention of the composite resin core material: An in-vitro study

An evaluation of the effect of the chemical and mechanical surface treatment of the glass fibre posts on the retention of the composite resin core material: An in-vitro study - APRD- Print ISSN No: - 2581-4796 Online ISSN No:- 2581-480X Article DOI No:- 10.18231/j.aprd.2019.025, IP Annals of Prosthodontics and Restorat

Effect of nanotitanium dioxide fillers addition on the compressive strength of an experimental composite resin core material

Effect of nanotitanium dioxide fillers addition on the compressive strength of an experimental composite resin core material

Effect of Silanized Silicon Dioxide and Titanium Dioxide Nanoparticles Loading on the Compressive Strength of Prepared Composite Core Material

the aim of this study was to assess the effect of silanized silicon dioxide and titanium dioxide nanoparticles loading on the compressive strength of experimentally prepared resin composite core material. Materials andMethods: Resin matrix was prepared by adding 70 wt% Bis-GMA,30 wt% TEGDMA, 0.5 wt% CQ and 0.5 wt% EDAB. Sintering of the silica nanoparticles was performed and then the silanized sintered silica fillers together with titanium dioxide nanoparticles and silica nanoparticles were mixed with the prepared resin matrix. Specimens of the experimental and control resin composite were prepared in split Teflon moulds (4x6mm) for compressive strength testing using universal testing machine. Results: There was no statistically significant difference between results of the experimental and control resin composites. Conclusion: Addition of up to 85 wt% of nanofillers into traditional resin matrix produced a resin composite with comparable compressive strength to that of the commercial composite products commonly used as core material

Effect of Silanized Silicon Dioxide and Titanium Dioxide Nanoparticles Loading on the Compressive Strength of Prepared Composite Core Material

the aim of this study was to assess the effect of silanized silicon dioxide and titanium dioxide nanoparticles loading on the compressive strength of experimentally prepared resin composite core material. Materials andMethods: Resin matrix was prepared by adding 70 wt% Bis-GMA,30 wt% TEGDMA, 0.5 wt% CQ and 0.5 wt% EDAB. Sintering of the silica nanoparticles was performed and then the silanized sintered silica fillers together with titanium dioxide nanoparticles and silica nanoparticles were mixed with the prepared resin matrix. Specimens of the experimental and control resin composite were prepared in split Teflon moulds (4x6mm) for compressive strength testing using universal testing machine. Results: There was no statistically significant difference between results of the experimental and control resin composites. Conclusion: Addition of up to 85 wt% of nanofillers into traditional resin matrix produced a resin composite with comparable compressive strength to that of the commercial composite products commonly used as core material

Effect of Nanotitanium Dioxide Fillers Addition on yhe Compressive Strength of Experimental Composite Rein Core Material

Purpose: The objective of this study was to prepare an experimental dental composite resin core material loaded with prepared nanotitanium dioxide fillers and to evaluate the compressive strength of the experimentally prepared composite materials Materials and methods: prepared nanotitanium dioxidefillers, commercial nanosilica were used as a filler added to the experimentally prepared resin matrix and commercially available resin core material Nexcomp was used as a control. Preparation and characterization of a nanotitanium dioxide fillers through the following techniques: X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy analysis, Scanning electron microscopic (SEM) analysis, EDX analysis,Transmission electron microscopy (TEM) analysis, and Thermal gravimetric analysis (TGA). then added to the prepared resin matrix BisGMA: TEDGMA(70%:30%) mixed with 0.5 wt% camphorquinone and 0.5 wt% ethyldimethyl amine. Testing of compressive strength was done. Results: revealed that there was no significant difference in the compressive strength between the experimental and Nexcomp core composite. Conclusions: It was concluded that experimental core composite showed a comparable mechanical properties to a commercial nanocomposite core resin regarding Compressive strength

Influence of Different Post Luting Cements on the Fracture Strength of Endodontically Treated Teeth: An In Vitro Study.

Objective:To evaluate the fracture resistance of endodontically treated mandibular premolars restored with glass fiber posts using different luting agents.Methods:Twenty-four extracted single-rooted mandibular premolars were endodontically treated, and post spaces were prepared to receive fiber posts. They were assigned to three test groups (n=8) according to the type of cement used for the cementation of glass fiber posts: RC group: adhesive resin cement group (etch and rinse), SC group: self-adhesive resin cement group, and GC group: glass ionomer cement group. Teeth in all groups were adhesively restored with a composite resin core material and crowned with Ni-Cr crowns. All specimens were subjected to tangential loading using a universal testing machine until fracture at 30°. Failure loads were recorded, and data were analyzed using one-way ANOVA followed by Tukey’s HSD test (α=0.05).Results:Specimens in the RC group were more resistant (258.3±12.7 N) to fracture than those in the SC (218.7±11.1 N) and GC (165.4±8.9 N) groups (P≤0.001). One-way ANOVA indicated that the type of cement had a significant effect on the fracture resistance of endodontically treated lower premolars (P≤0.001).Conclusion:The type of cement that was used to fix glass fiber posts was a determining factor of the fracture resistance of endodontically treated lower premolars.

Research on bond durability among different core materials and zirconia ceramic cemented by self-adhesive resin cements

This research estimated shear bond durability of zirconia and different substrates cemented by two self-adhesive resin cements (Clearfil SA Luting and RelyX U100) before and after aging conditioning. Machined zirconia ceramic discs were cemented with four kinds of core material (cobalt-chromium alloy, flowable composite resin core material, packable composite resin, and dentin) with two self-adhesive resin cements (Clearfil SA Luting and RelyX U100). All specimens were divided into eight test groups, and each test group was divided into two subgroups. Each subgroup was subjected to shear test before and after 10 000 thermal cycles. All factors (core materials, cements, and thermal cycle) significantly influenced bond durability of zirconia ceramic (P<0.00 1). After 10 000 thermal cycles, significant decrease was not observed in shear bond strength of cobalt-chromium alloy luted with Clearfil SA Luting (P>0.05); observed shear bond strength was significantly higher than those of other substrates (P<0.05). Significantly higher shear bond strength was noted in Clearfil SA Luting luted with cobalt-chromium alloy, flowable composite resin core material, and packable composite resin than that of RelyX U100 (P<0.05). However, significant difference was not observed in shear bond strength of dentin luted with Clearfil SA Luting and RelyX U100 (P>0.05). Different core materials and self-adhesive resin cements can significantly affect bond durability of zirconia ceramic. .

Mechanical Properties Study of Plasma Treated Epoxy-Base Post in Dual-Material Systems

Improvement of adhesion between epoxy based post and composite resin core materials by low temperature plasma is an on-going dental material development. To systematically investigate the effects of surface change on the material’s chemical and mechanical properties, three series of two component materials, epoxy/urethane dimethacrylate (UDMA), epoxy/polyethylene (PE), and epoxy/poly(methylmethacrylate) (PMMA), were compared with dental epoxy based post/composite resin core. Each dual-materials system was modeled at an atomistic level. A molecular dynamics (MD) method with COMPASS force field was employed to simulate the most probable functionalization and the materials physical properties changes. Material surface modification was modeled and optimized using quantum calculations based on experimental characterization. To validate calculation results, the effect of plasma treatment on the mechanical properties of the dental post materials were examined by tensile pull out test.

Effect of phosphoric acid on microtensile bond strength between dimethacrylate-based fiber post and resin composite core material

Effect of phosphoric acid on microtensile bond strength between dimethacrylate-based fiber post and resin composite core material

A Comparative Evaluation of Stress Distribution by Three Different Designs of Prefabricated Metal Posts on Endodontically Treated Permanent Maxillary Central Incisor: A Three-dimensional Finite Element Study

ABSTRACTPurpose of the study: This study intends to evaluate and compare the stress distribution by three designs of prefabricated metal posts, parallel post (EG post), parallel post with coronal flare (i-post) and a tapered post (Filpost) in endodontically treated permanent maxillary central incisor. This study will help the dentists to choose the post that would generate the least stress in endodontically treated teeth.ProcedureThree-dimensional (3D) finite element models were developed. The physical models include composite resin core material, dentin, endodontic post, luting cement and guttapercha. They were subjected to compressive load of 100 N at 135° angle with respect to longitudinal axis of tooth, above the level of cingulum, simulating the load condition in oral cavity and the effects of three posts on stress distribution, in endodontically treated maxillary central incisor was evaluated.ResultsStress distribution was found to be better in the models having parallel post and parallel post with the coronal flare. Coronal flare has an added advantage of better fit in the root canal.ConclusionIt was found that the stresses in maxillary central incisor with the parallel post with coronal flare were well distributed.How to cite this articleMengal GP, Nadgere J, Ram SM, Shah N. A Comparative Evaluation of Stress Distribution by Three Different Designs of Prefabricated Metal Posts on Endodontically Treated Permanent Maxillary Central Incisor: A Three-dimensional Finite Element Study. J Contemp Dent 2015;5(3):123-130.