Dalia Abuelenain - Academia.edu (original) (raw)

Papers by Dalia Abuelenain

Medical science monitor, Apr 15, 2024

BMC oral health, May 10, 2024

Materials

Background: We aim to evaluate the effect of surface conditioning, bonding agents and composite t... more Background: We aim to evaluate the effect of surface conditioning, bonding agents and composite types on surface roughness (SR) and shear bond strength (SBS) of clear aligner composite attachments bonded to ceramics. Methods: One hundred and eighty IPS e.max CAD specimens were prepared. For SR, 60 specimens were divided according to surface conditioning (n = 15) into four groups: control, 9.6% hydrofluoric acid (HFA), 37% phosphoric acid (PhA), air abrasion (AA). SR was measured using a Profilometer and Atomic Force Microscopy. For SBS, 120 specimens were divided according to conditioning methods (n = 40) (9.6% HFA and 37% PhA or AA), then according to bonding agents (n = 20) (Assure universal bond (AUB) or Single bond universal (SBU)) and then according to composite type (n = 10): Filtek™ Z350 and Filtek™ Z350 XT flowable composite. SBS was measured using Instron testing machine. Descriptive and group comparison were calculated (p < 0.05). Results: AA had the highest SR, while t...

Egyptian Dental Journal, 2018

The aim of the study was to investigate the influence of dentin surface preparation with acid etc... more The aim of the study was to investigate the influence of dentin surface preparation with acid etching or chitosan treatment on dentin wettability and shear bond strength to resin composite using self-etch adhesive. Methods: Fifteen human sound extracted third molars were used in the study. Dentin disks were cut from the crown for evaluation of dentin wettability, and the remaining part of the crown was used for the shear test. Dentin discs were divided randomly into 3 groups (n=5) treated as follow: G1: control, G2: acid etched with 32% phosphoric acid, and G3: treated with Chitosan for 60 s. Contact angle of treated dentin surfaces with a self-etch single bond universal adhesive was measured using a drop shape analyzer. The remaining crowns used for shear bond strength test (SBS) were divided randomly into three groups (n=5) and prepared in the same manner used for wetting evaluation. Nano-hybrid composite material were bonded to treated dentin surface using self-etch adhesive. Samples were subjected to SBS testing in a universal testing machine. Results obtained, showed statistically significant lower contact angle after chitosan treatment of dentin surfaces as compared to control and acid etched groups (p<0.05). On the other hand, both acid etching and chitosan treatment of dentin surfaces resulted in a statistically significant lower SBS compared to control untreated group (p<0.05). Conclusion: Bonding to dentin using self-etch adhesive is best achieved with direct application of adhesive resin on untreated dentin surface.

International Journal of Adhesion and Adhesives, 2021

to improve the antibacterial action of a two-step total-etch dental adhesive by using titanium di... more to improve the antibacterial action of a two-step total-etch dental adhesive by using titanium dioxide-doped phosphate glass microspheres (GMs) without affecting its penetration ability. Materials and Methods: Five and 10 wt% of APTES silanized [surface treated with 3-Aminopropyltriethoxysilane (APTES)] and non-silanized GMs have been used as a filler to Adper TM Single Bond 2 Refill. The morphology, chemistry and ζ-potential of GMs have been investigated using scanning electron microscopy, Fourier transform infra-red (FTIR) spectroscopy and Zeta-sizer respectively. The chemistry and antibacterial action of filled adhesive have been investigated using FTIR and nitrocellulose filter membranes (NFM) S. mutans biofilm model respectively. The number of colony forming units (CFU) per NFM was considered. The contact angle and microtensile bond strength of adhesives to mid-coronal dentin, as a measure of its penetration ability, have been investigated using a Drop Shape Analyzer and microtensile testing machine respectively. Adper TM Single Bond 2 Refill was used as a control. Results: The size of GMs varied from 60-200 µm. The silanization process was confirmed by reduction in ζ-potential [-7 (±2) mV] and the presence of amide (1500-1600 cm-1), C-N (1380 cm-1), Si-O-Si (1096 cm-1) and Si-O-C (780 cm-1) peaks. Incorporation of GMs had no adverse effect on monomer conversion. All tested adhesives including the control showed significantly higher antibacterial action (~5-7 log10 reduction in CFU) than the NFM control. All filled adhesives showed significantly higher antibacterial action (~1-2 log10 reduction in CFU) than the control adhesive. The non-silanized GMs filled adhesives showed the highest antibacterial action against S. mutans biofilm formation. The presence of silanized GMs did not affect the wetting but increased the microtensile bond strength of the adhesive to dentin. Conclusion: Glass microsphere modified adhesives could be promising to reduce the possibility of recurrent caries around restorations.

The Open Dentistry Journal, 2021

Background: Preserving the strength and durability of dentin bonds is a concern of dental researc... more Background: Preserving the strength and durability of dentin bonds is a concern of dental researchers and practitioners. Objective: The aim of this study was to investigate the effect of treating etched dentin with vitamin C and curcumin suspension as cross-linking agents on the shear bond strength and durability of a universal dental adhesive. Methods: Extracted human third molar teeth were collected. Fifty-six flat coronal dentin surfaces were divided equally into four groups: (1) treated with adhesives; (2) etched with 37% H3PO4 for 10s before application of adhesives; (3) same as group (2), but with dentin treated with 2.5% curcumin suspension for 60s before the application of adhesive; and (4) same as group (3), but with the use of a 20% vitamin C suspension instead of a curcumin suspension. Filtek Z350XT composite was built for all samples. Half of the samples in each group were subjected to thermocycling. Shear bond strength was measured using a universal testing machine. Sca...

Journal of Dental Sciences, 2020

Background/purpose: Increasing the bond strength between the orthodontic brackets and all-ceramic... more Background/purpose: Increasing the bond strength between the orthodontic brackets and all-ceramic materials is one of the challenges facing orthodontists. The purpose of this study is to assess the shear bond strength (SBS) of metal brackets to two types of all ceramic materials using various surface mechanical and chemical conditioning methods. Materials and methods: Sixty ceramic blocks were prepared using two types of all ceramic materials (IPS e.max and VITA Suprinityâ PC) and treated with 3 surface treatments; surface etching with 9.6% hydrofluoric acid (HFA) for 2 mins; surface roughening with Sof-Lex finishing discs; and surface roughening with Sof-Lex finishing discs and etching with HFA. Metal brackets were attached to the surface of the ceramic blocks using light cure orthodontic adhesive. Samples were subjected to 2000 thermo-cycles (5e50 C) and the SBS was assessed using Instron machine. The adhesive remnant index (ARI) was evaluated under light microscope. Descriptive and group comparison were calculated using Two-way ANOVA, Post-hoc Tukey's and Chi-square tests and significance level set at (P < 0.05). Results: surface roughening of both ceramic materials with Sof-Lex discs and HFA resulted in a significant increase in SBS compared to other experimental groups (P < 0.05). However, VITA Suprinity ceramic prepared with Sof-Lex discs only showed the lowest SBS. The distribution of the ARI scores was significantly different between the groups (P < 0.05). Conclusion: Surface preparation of all ceramic materials with Sof-Lex discs and hydrofluoric

Egyptian Dental Journal, 2017

Sickle cell anemia patients with dental anomalies represent a difficult challenge for the prosthe... more Sickle cell anemia patients with dental anomalies represent a difficult challenge for the prosthetic dentist. Proper treatment planning with the medical and dental management of these patients are important prerequisites for successful results. This case report describes a full-mouth rehabilitation of a sickle cell anemia patient with worn-down dentition including the treatment planning, medical consultation, correction of vertical dimensions of occlusion, preparation, and restoration with porcelain fused to metal crowns.

International Journal of Adhesion and Adhesives, 2018

The purpose of the present study was to evaluate dentin hardness and microtensile strength (μTS) ... more The purpose of the present study was to evaluate dentin hardness and microtensile strength (μTS) after a simulated clinical procedure of acid etching followed by surface treatment with proposed different cross-linking agents' protocols (1% riboflavin activated by either blue light or UVA light and Carbodiimide). Materials and Method: For Vickers hardness number (VHN), coronal dentinal discs were prepared and divided into five groups (n = 5) according to the cross-linking protocol. Crosslinking agents were applied after the samples were etched with 37% phosphoric acid, rinsed, and dried. The protocols included were as follows: Groups 1 and 2: surface treatment by 1% riboflavin activated by blue light (BL) for 20 s or 60 s, respectively. Groups 3 and 4: 1% riboflavin activated by UVA light for 20 s or 60 s, respectively. Group 5: 0.5 M carbodiimide surface treatment for 60 s. Microhardness of each group was tested at three stages: before treatment, after acid etching, and finally after application of the cross-linking agent. For μTS, dentin discs were sectioned into bars and divided into seven groups (n = 10): Group 1: control. Group 2: acid-etched. Groups 3-7: received the same cross-linking agent protocols as described for hardness tests. A microtensile tester was used to test the μTS. Results: There was a significant reduction in VHN after acid etching, which was retained after attempted superficial cross-linking of dentin discs. However, there was no significant difference in the microtensile strength of dentin bars after acid etching and cross-linking in comparison to control untreated bars. Conclusion: Under the limitations of this study, the acid etching of dentin reduced hardness, but the use of proposed cross-linking substances did not improve the hardness or μTS. An explanation for the reported improvement in resin composite bonding to etched and crosslinked dentin surfaces remains elusive.

Journal of Dentistry and Oral Care Medicine, 2017

To evaluate the flexure strength and flexure modulus of nano-filled dental composite after differ... more To evaluate the flexure strength and flexure modulus of nano-filled dental composite after different storage conditions.

International Journal of Adhesion and Adhesives, 2017

Understanding Dental Caries, 2016

Many reports have indicated that resin bond strengths to noncarious sclerotic cervical dentin are... more Many reports have indicated that resin bond strengths to noncarious sclerotic cervical dentin are lower than bonds made to normal dentin. This is thought to be due to tubule occlusion by acid-resistant mineral salts, preventing resin tag formation following acid etching. The purpose of this review was to critically examine what is known about the structure of this type of dentin. Recent transmission electron microscopy revealed that in addition to occlusion of the tubules by mineral crystals, many parts of wedge-shaped cervical lesions contain a hypermineralized surface that resists the etching action of both self-etching primers and phosphoric acid. This layer prevents hybridization of the underlying sclerotic dentin. In addition, bacteria are often detected on top of the hypermineralized layer. Sometimes the bacteria were embedded in a partially mineralized matrix. Acidic conditioners and resins penetrate variable distances into these multilayered structures. Examination of both sides of the failed bonds revealed a wide variation in fracture patterns that involved all of these structures. Microtensile bond strengths to the occlusal, gingival, and deepest portions of these wedge-shaped lesions are significantly lower than similar areas artificially prepared in normal teeth. When resin bonds to sclerotic dentin are extended to include peripheral sound dentin, their bond strengths are probably high enough to permit retention of class V restorations by adhesion, without additional retention.

Dental materials : official publication of the Academy of Dental Materials, Sep 15, 2016

To determine if acid-etched, cross-linked dentin can be dehydrated without lowering bond strength... more To determine if acid-etched, cross-linked dentin can be dehydrated without lowering bond strength below that of cross-linked wet-bonded dentin in vitro. Using extracted human third molars, control acid-etched dentin was bonded with Single Bond Plus, using either the wet- or dry-bonding technique. Experimental acid-etched dentin was treated with 5mass% grape seed extract (GSE) in different solvents for 1min before undergoing wet vs dry resin-dentin bonding with Single Bond Plus. Completely demineralized dentin beams were treated with 5% GSE for 0, 1 or 10min, before measuring stiffness by 3-point flexure. Other completely demineralized beams were treated similarly and then incubated in buffer for 1 week to measure the collagen solubilization by endogenous dentin proteases. 24h microtensile bond strengths (μTBS) in wet and dry controls were 53.5±3.6 and 9.4±1.8MPa, respectively (p<0.05). 5% GSE in water gave μTBS of 53.7±3.4 and 39.1±9.7MPa (p<0.05), respectively, while 5% GSE i...

Journal of dentistry, Jan 16, 2015

The aim of the current study was to evaluate the effect of 2% CHX and 2% CHX-methacrylate compare... more The aim of the current study was to evaluate the effect of 2% CHX and 2% CHX-methacrylate compared to the resin-dentin bonds created by a two-step etch-and-rinse adhesive system after 24h, 6 m and 12 m. Microtensile bond strengths and interfacial nanoleakage within resin-dentin interfaces created by Adper Single Bond 2, with or without CHX or CHX-methacrylate pre-treatment for 30 s on acid-etched dentin surfaces, were evaluated after 24h, 6 m and 12 m of storage in distilled water at 37⁰C. Twelve months of storage resulted in a significant decrease in microtensile bond strength in the control group, and significant increases in silver nanoleakage. In contrast, Single Bond 2 + CHX, and to a greater extent CHX-methacrylate, significantly reduced the rate of deterioration of resin-dentin interfaces over the 12 m water storage period, in terms of bond strength. Similar to Single Bond 2 +CHX, Single Bond + CHX-methacrylates reduced the degradation of resin-bonded interfaces over a 12 mon...

Objective: Previous work with nanogel additives in dental resins demonstrated significant reducti... more Objective: Previous work with nanogel additives in dental resins demonstrated significant reductions in polymerization shrinkage stresses even at relatively low nanogel concentrations. This study examines effects of low to moderate nanogel loading on physical and mechanical properties in both resin and composite formulations. Method: Nanogels were synthesized through copolymerization of isobornyl methacrylate with urethane dimethacrylate. Mercaptoethanol and dodecanethiol were used as chain-transfer agents and nanogels were refunctionalized with reactive methacrylate groups using isocyanatoethyl methacrylate. Nanogels were added at 0, 15, or 30 wt% to either 70/30 and 50/50 mass ratios of BisGMA/TEGDMA. Composite formulations contained 65 wt% 0.4µm silanated barium glass. Property evaluation included viscosity, reaction kinetics/conversion, stress, polymerization shrinkage and mechanical properties. Result: Approximately proportional reduction in shrinkage with nanogel content is ob...

Decision making in dentistry relies on thorough analysis of different mechanical properties to ch... more Decision making in dentistry relies on thorough analysis of different mechanical properties to choose the material with the highest possible longevity under the harsh craniofacial stresses. Objective: This study aimed to investigate the mechanical properties of different commercially available dental composites to choose the optimum composite with the highest possible tolerance to occlusal stresses. Method: Six composite resins were used, a nano-hybrid (Tetric N-Ceram), hybrid (Tetric N-Ceram Bulk Fill), nano-hybrid (IPS Empress Direct), a nanofill (Filtek Z350 XT), microhybrid (Filtek Z250) and silorane-based resin composite (Filtek P90). Rectangular specimens (n=6) of 20x2x2 mm3were used to measure the flexure strength and modulus using three-point bending test. Cylindrical specimens of 8 mm length and 4 mm diameter, however, were used for measuring the compressive strength. All the mechanical properties were measured using universal testing machine (Instron 5969, USA). Results: S...

Journal of Prosthodontics, 2014

Purpose: This study compares the FEA-calculated stresses generated within the supporting periodon... more Purpose: This study compares the FEA-calculated stresses generated within the supporting periodontal structure of a mandibular second molar restored with a full ceramic crown and with a porcelain-fused-to-metal (PFM) crown, each resisting occlusal forces acting at different inclinations. Materials and Methods: Three-dimensional finite element models representing the crown of an unrestored mandibular second molar and two relevant restoration designs were constructed. Two designs represented the molar restored with a full ceramic crown and with a PFM crown, each cemented with the same resin cement. Occlusion was assumed at three contact areas, which equally shared a 100 N force. The analysis was carried out for forces located in the bucco-axial-lingual plane at five inclinations, 0, 22.5°, 45°, 67.5°, and 90°, measured from the axial direction of the tooth. The magnitudes and sites of the maximum equivalent stress (MES) generated within the supporting periodontium of each analyzed model were collected. Results: Generally, there were no significant differences in the site and magnitude of MES in the regions of the supporting structure for the analyzed models. The MES was located at the tooth periodontal ligament (PDL) bifurcation area and distal root apex, crestal bone at the junction between cortical and cancellous bone, and the distal wall of the mesial root socket of cancellous bone. The highest stresses corresponded to a horizontal load, followed by the axial load in the PDL and cortical zones. The results show opposite observations for the cancellous bone. The lowest stresses were generated under a load inclination between 22.5°and 45°. Conclusion: Considering the stresses generated within the supporting structures, the present work validates, by calculation, the proposed clinical use of either a full ceramic crown or a PFM crown as a restoration for mandibular second molars.

Objective: To evaluate the surface roughness of three types of dental composites after different ... more Objective: To evaluate the surface roughness of three types of dental composites after different finishing and polishing techniques. Methods: A total of 60 disks were prepared using three types of dental composites (Nanofilled; Filtek Superme, Microhybrid; Filtek Z250 and Herculite classic) (n= 20). Each group was randomly divided into four subgroups according to the polishing system (n= 5). For the control group, samples were left unfinished or polished after removal of the Mylar Strip. For the other three subgroups, samples were polished with OptraPol; OneGloss; or Sof-Lex disks. Surface roughness was determined using profilometer. Data were analyzed by 2-way ANOVA followed by a Tukey multiple comparisons test ( = 0.05). Results: The surface roughness results were significantly influenced by the different types of composite resins and the different polishing techniques used in the study (P<0 .001). The lowest Ra values were obtained with the control and Sof-Lex disks groups (P&...

Objectives: In this study, a novel set of materials, EXOTHANE™ Elastomers, have been investigated... more Objectives: In this study, a novel set of materials, EXOTHANE™ Elastomers, have been investigated through mechanical testing alongside traditional polymeric matrix resins; urethane dimethacrylate (UDMA) and a blend of bis[p-(3-methacryloxy-2-hydroxypropoxy)phenyl]propane( BisGMA ) and triethylene glycol dimethacrylate (TEGDMA). Methods: Mechanical testing data was obtained by photo-initiating and curing the "neat" materials under a UVA light. Stress/strain curves for these materials were obtained using a universal tester with a 5 kN load cell and a crosshead speed of 10 mm/min. The shrinkage stress was determined using a tensometer. Volumetric shrinkage was measured using a linometer (ACTA). Conversion and real-time monitoring of the polymerization kinetics was carried out using the near-infrared (NIR) spectrum in a Fourier transform spectrophotometer (FTIR). Results: Results of mechanical testing indicate that Exothanes have superior toughness at max strength compared to ...

Objective: This study seeks to correlate the interrelated properties of conversion, shrinkage, mo... more Objective: This study seeks to correlate the interrelated properties of conversion, shrinkage, modulus and stress as dimethacrylate networks transition from the rubbery to the glassy state during photopolymerization. Method: An unfilled BisGMA/TEGDMA resin with 0.1wt% 2,2-dimethoxy-2-phenylacetophenone was photocured at 23°C using UV light (365nm; 10mW/cm2) for various irradiation intervals (10-60s) to alter the degree of conversion. Fiber optic near-infrared spectroscopy permitted coupling of real-time conversion measurement with dynamic polymerization shrinkage (linometer), stress (tensometer) and modulus (dynamic mechanical analyzer) development profiles (monitored continuously for at least 10min of post-cure). Temperature variation during polymerization was determined in selected specimens with an embedded thermocouple. Result: Irradiation for longer intervals produced higher final conversion, which ranged from 44.2±0.6% to 56.3±0.8%. Of more interest is the amount of post-irrad...