Abstract: Aims: To evaluate the biocompatibility and osteogenic potential of calcium silicate-based cements (CSCs) modified with casein phosphopeptide – amorphous calcium phosphate (CPP-ACP) and casein phosphopeptide – amorphous calcium fluoride phosphate (CPP-ACFP). Materials and method: Commercially available CSCs were modified with CPP-ACP or CPP-ACFP to prepare CPP-ACP and CPP-ACFP-modified Biodentine™ (0%, 0.5%, 4.0% w/w), Angelus® MTA (0%, 0.5%, 2.0% w/w) and NEX® MTA (0%, 0.5%, 3.0% w/w).  For each group, 50 mg, 300 mg and 1500 mg of the cement mixed according to manufacturers’ instructions were placed and adapted at the bottom of 96 well, 24 well and 6 well (respectively) cell culture plates. After 24 h, the cement-coated plates were sterilised by ultraviolet light for 1 h. MG-63, MC3T3-E1, HGF-1, NIH3T3 cells were grown in the cement-coated plates and the cellular proliferation, cellular toxicity, alkaline phosphatase activity, cytokine production (interleukin-1α; IL-1α and interleukin-6; IL-6) and expression of mineralisation-associated proteins (collagen type 1, osteocalcin and osteopontin) were determined. Results: The addition of 0.5% CPP-ACP and 4.0% CPP-ACFP to Biodentine™, and 2.0% CPP-ACFP to Angelus® MTA significantly reduced the proliferation of MG-63.  The addition of 4.0% CPP-ACP and 4.0% CPP-ACFP to Biodentine™, 2.0% CPP-ACFP to Angelus® MTA and 3.0% CPP-ACFP to NEX® MTA significantly reduced the proliferation of MC3T3-E1 cells. The tested cements, with and without CPP-ACP and CPP-ACFP, did not induce cellular toxicity nor IL-1α release. The addition of CPP-ACP and CPP-ACFP to Biodentine™ and NEX® MTA, and the addition of CPP-ACP to Angelus® MTA significantly increased the alkaline phosphatase activity of MG-63 cells. The presence of 4.0% CPP-ACP in Biodentine™, 0.5% and 2.0% CPP-ACP in Angelus® MTA, 0.5% CPP-ACFP in Angelus® MTA, and 0.5% CPP-ACFP in NEX® MTA significantly increased the alkaline phosphatase activity of MC3T3-E1 cells. All the tested cements significantly increased the release of IL-6 from MG-63 compared with negative control. The presence of CPP-ACP and CPP-ACFP in NEX® MTA significantly increased the release of IL-6 from MG-63 compared with unmodified NEX® MTA. MC3T3-E1 cells grown on Biodentine™ (unmodified and modified groups) and 3.0% CPP-ACFP-modified NEX® MTA released significantly higher IL-6 compared with negative control. 0.5% CPP-ACFP-modified Biodentine™ and 3.0% CPP-ACFP-modified NEX® MTA induced significantly higher IL-6 release from MC3T3-E1 compared with unmodified Biodentine™ and unmodified NEX® MTA respectively. The tested cements (especially Biodentine™, Angelus® MTA and CPP-ACFP-modified cements) induced the secretion of mineralisation-associated proteins (especially collagen type 1 and osteocalcin).Conclusions: The tested cements are biocompatible, and they could serve as a suitable scaffold which supports cellular proliferation. The addition of CPP-ACP and CPP-ACFP to CSCs improved the cements’ potential to induce osteoblastic differentiation.

Abstract: Aims: To investigate the effects of the incorporation of hydroxyapatite nanoparticles (HA NPs) with size (20 nm) at two concentrations (0.5% and 1%) on the hardness of heat-cured acrylic resin. Materials and methods: The total number of specimens was thirty divided into ten specimens (control, 0.5 % HA NPs, and 1 % HA NPs), the hardness was performed using shore D (Durometer), FTIR test was performed using (BRUKER LASER CLASS 1). The statistical analysis was done by using the SPSS program including descriptive statistics, ANOVA, and Duncan's test at p ≤ 0.05. Results: The results demonstrated that there was a significant increase in the hardness for the PMMA-HA nanocomposite at HA nanoparticles (0.5%) and (1%) when compared to control. Conclusion: hydroxyapatite nanoparticles as dental fillers at 0.5% and 1% by weight increased the hardness of PMMA denture base material.

Abstract: Aims: To investigate the effects of the incorporation of hydroxyapatite nanoparticles (HA NPs) with size (20 nm) at two concentrations (0.5% and 1%) on the flexural strength and impact strength of heat-cured acrylic resin. Materials and methods: The total number of specimens was sixty which were divided into two groups, thirty specimens for each test (flexural strength test and impact strength test), ten specimens for each subgroup (control, 0.5 % HA NPs and 1 % HA NPs), the flexural strength was performed using the universal testing machine, and impact strength using Charpy impact tester. The statistical analysis was done by using the SPSS program including descriptive statistics, ANOVA, and Duncan's test at p ≤ 0.05. Results: The results demonstrated that there was a significant increase in the flexural and impact strength for the PMMA-HA nanocomposite at HA nanoparticles (0.5%) and (1%) when compared to control. Conclusion: the use of hydroxyapatite nanoparticles as dental fillers at 0.5% and 1% by weight enhanced the flexural strength and impact strength of PMMA denture base material.

Abstract: Aims: The study aimed to assess the tensile bond strength of modified-Heliosit orthodontic adhesive with different concentrations of seashell or zirconium oxide nanoparticles. Materials and methods: Thirty-five sound-extracted human premolars were collected. Hydroxyapatite nanoparticles were manually prepared from natural snail seashells. Heliosit orthodontic adhesive was modified by (8%, 10%, and 12% seashell), and (1%, 3%, and 5% zirconium oxide) nanoparticles. Standard edgewise brackets were bonded to buccal enamel surfaces of the samples of control and six modified adhesive groups. At 24 h after bonding, tensile bond strength was measured. The adhesive remnant index was scored under (10X) magnification power of the stereomicroscope after de-bonding. The chemical characteristics of orthodontic adhesive material were explored before and after mixing with seashell and zirconium oxide nanoparticles by using Fourier Transform Infrared Spectrometry. Results: Seashell groups (8, 10, & 12 %) containing hydroxyapatite nanoparticles and zirconium oxide nanoparticles groups (1%, 3%, and 5%) had a higher tensile bond strength mean value than the control group, (10%) seashell group had the highest mean value, while the least mean value was in the control group with statistically significant differences between them. Regarding the adhesive remnant index, no significant differences were found among the studying groups. Conclusions: the addition of (10%) seashell nanoparticles had the best performance and improved the tensile bond strength of Heliosit orthodontic adhesive without violating the remnant of adhesive on the buccal enamel surface after brackets de-bonding or inducing any chemical reactions with the resin adhesive.

Abstract: Aims: To evaluate the effect of adding salinized zirconium oxide (ZrO2) and silicon oxide (SiO2) nanoparticles in two concentrations on the translucency of heat-cured denture base material.  Materials and methods: Fifty discs (15×2.5mm) ere prepared in accordioning to the manufacturer's instructions and divided into five groups, control without nanoparticles reinforcement, 1%ZrO2, 3%ZrO2, 1%SiO2 and 3%SiO2 NPs reinforcement. Translucency was measured using a colorimeter. Results: The result showed a highly significant (P ≤ 0.01) decrease in the translucency ZrO2 Np reinforced more reduce in the translucency than SiO2 Np reinforced group. The 3% by weight is more reduced than 1% by weight. Conclusions: Both nanoparticles reduced the translucency. 

Abstract: Aims: The purpose of this study was to test different design parameters for ISFPD frameworks fabricated from fiber-reinforced composite and polyetheretherketone. Material and Methods: 12 different framework digital designs made using the AutoCAD program were sent to Autodesk Inventor 2023 for finite element analysis (FEA), these designs included 6 different connector designs according to cross-sectional shape and height-to-width ratio as follows: (ellipse3:2, ellipse 4:3, round, ellipse3:4, ellipse2:3 and triangular9:8) with 2 different connector cross-sectional areas (12mm2 and 16mm2) and were presented to the FEA program as two different materials (PEEK and FRC) to study stress distribution and displacement under 800N load. Stress and displacement values were used to determine the suitable framework material, connector cross-sectional area, and design. Results: FEA had resulted in FRC frameworks exhibiting higher resistance to bending than PEEK frameworks. 16mm2 connector cross-sectional area resulted in higher resistance to loading than 12mm2 connectors. Ellipse connectors with 3:2 height-to-width designs also resulted in the highest resistance to bending compared to other designs. Triangular designs resulted in the highest areas of stress concentration among other designs. Conclusions: Framework design should be considered to allow safe usage of PEEK and FRC as framework materials, FRC framework is more resistant to bending, and increasing the height of the connector increases the resistance to bending thus making ellipse designs with higher height-to-width ratio better in resistance to bending, triangular cross-section designs are not recommended.

Abstract: Aims: The purpose of the current study is to compare the impact of three different treatment approaches on the surface microhardness of the enamel of third molar teeth.  Materials and Methods: An in vitro study was done on fifty extracted impacted third molars. All samples were immersed in solutions of pH cycle for 10 days (demineralizing solution for 3 hours, remineralizing solution for 20 hours, and artificial saliva for 30 minutes twice daily). Then the samples were divided randomly into 5 groups according to enamel surface treatment, group1: Colgate (containing Arginine) toothpaste, group2: GC (containing Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-tooth mousse, group 3: Sensodyne (containing NovaMin) toothpaste group 4: distilled water and group 5: pH cycle solutions. The microhardness numbers were calculated from the length of the indentation on the enamel surface, the indentation length was determined microscopically with 70X magnification.  An ANOVA was constructed (value P ≤ 0.05) followed by Duncan’s post –hoc test for comparisons of mean values. Results: there were significant differences among the study groups with respect to Vickers microhardness (VMH) mean values of samples. The lowest value was for the control group after the pH cycle followed by the Colgate (containing Arginine) group and the highest value was for the control group before the pH cycle followed by the Sensodyne (containing NovaMin) group. Conclusions: Sensodyne (containing NovaMin) toothpaste is more effective in restoring the hardness of artificial WSLs when compared with GC (containing CPP-ACP) and Colgate (containing Arginine) toothpaste

Abstract: Aims: To compare the extraoral and intraoral scanners' accuracy in obtaining implant impressions using an in-vitro reference model. Materials and methods: An upper master model was fabricated with two parallel dental implants at the first and second premolars missing regions in size (4.0mm in diameter and 10mm in length); twenty impressions were made using the intraoral and extraoral scanners to produce twenty digital impressions (10 for each one), which will result in twenty digital casts. The linear distance measurements were performed using (Medit Design) digital measurement by using Medit Intraoral Scanner. Results: In the digital part there was a highly significant difference between measurements for the oral scanner (MeditI500) and extraoral scanner Rainbow using Medit design, the intra-oral scanner (MeditI500) is the highest value which is at a level of significance p≤0.01. Conclusion: The Medit I500 Intra Oral Scanner is a more accurate impression technique than the Rainbow extraoral scanner in transferring implant position.

Abstract: Aims: This study aimed to compare the accuracy of implant position transfer using three impression materials with two techniques. Materials and methods: A master model was fabricated with two parallel dental implants at the first and second premolars missing regions in size (4.0mm in diameter and 10mm in length); Two traditional impression techniques (open and closed tray); Three silicone impression materials were used which are: Condensation, Additional (heavy and low) and Additional (medium) consistencies. Sixty conventional impressions were taken, ten impressions for each material and each technique. The linear distance measurements were performed using two methods: Digital Vernier and Digital measurement by using Medit Intraoral Scanner. Results: The open tray technique showed significantly fewer changes (P≤ 0.05) with linear distance measurements when compared to the control, while the closed tray technique showed significantly more changes (P≤ 0.05) with linear distance measurements when compared to the control. In comparing Medit Design and digital vernier as methods of measurement for both open and closed tray techniques; there was no significant difference in the accuracy of measurements for both of these two methods of measurement at a level of(P≤ 0.05). Conclusion: The additional silicone material is the best in its accuracy in transferring implant position for the (open and closed tray) conventional impression technique. The condensation silicone material is the worst in accuracy in transferring implant position for (open and closed tray) conventional impression technique. The open tray technique showed significantly more accuracy than the closed tray technique in transferring implant position in the traditional impression technique.

Abstract: Aims: To assess the effect of fibres reinforcement materials on flexural strength of heat cured denture-based resin. Materials and Methods: Sample of heat-cured acrylic resin were created and divided into: Control group (heat cured with no fibres addition) and two experimental groups (with fibres additive). The flexural strength was evaluated, calculated, and the information was statistically analysed using descriptive statistics, an analysis of variance (ANOVA), and Duncan multiple range tests with p ≤ 0.01 in SPSS Version 19. Results: The result showed highly significantly increase of flexural strength, untreated polypropylene fibres showed the highest flexural strength followed by untreated glass fibres. Conclusion: Reinforcement with fibres was an efficient approach for improvement of flexural strength of heat cured PMMA denture base resin.

Abstract: Aims: This study was carried out to evaluate the flexural strength of heat-polymerized acrylic denture base material that is readily accessible commercially after strengthening with two kinds of saline treatment fibers. Material and Methods: Samples were created using traditional acrylic resin, the same resin that was reinforced with glass and polypropylene fibers, and conventional acrylic resin alone. A 3-point bending test was used to gauge the flexibility of the material, and the findings were then examined using a one-way analysis of variance Results: The flexural strength of all strengthened samples was greater compared to that of standard acrylic resin; those reinforced with polypropylene fibers had the highest flexural strength, followed by those reinforced with glass fibers. Conclusion: Heat-polymerized PMMA denture resin's flexural strength was increased following reinforcing with treated glass or polypropylene fibers, within the confines of the fibers used in this study. These findings might be used as the bases of distal extension partial dentures and temporary fixed partial dentures.