Seminal BAX is significantly increased and seminal BCL2 is significantly decreased in men associated with Vx. Seminal BAX is significantly increased in men associated with bilateral Vx compared with unilateral Vx and in cases with Vx grade III compared with Vx grade I and II cases. Seminal BAX demonstrates significant negative correlation with sperm concentration, sperm motility, and sperm normal forms, whereas seminal BCL2 demonstrates significant reverse positive correlations.
The fracture resistance of wide root canals can be improved by using glass fiber-reinforced dowels relined with composite resin as an alternative to increasing the thickness of luting cement; however, the percentage nanoleakage would increase. On the other hand, the recently introduced prefabricated glass fiber-reinforced core can be considered a promising technique, but further investigations are necessary.
Statement of the problem: Conservative esthetic restorative dentistry has become an essential component in modern clinical practice. However, the inlay retained fixed partial dentures (IRFPDs) have a higher risk of fracture and dislodgement due to minimal preparations. Purpose: to compare fracture resistance and retention of Lithium disilicate (IPS e.max) and Polyetheretherketone (BioHPP) IRFPDs fabricated with heat-press technique and CAD/CAM system. Materials and Methods: Forty models, each including extracted mandibular 2 nd premolar and 2 nd molar embedded in an epoxy resin block with 10 mm intra-abutment distance representing missing mandibular 1 st molar were constructed. The premolar and molar of each model received standardized class II inlay preparations. The constructed models were randomly divided into four groups; Group (1): IPS e.max Press IRFPDs, Group (2): IPS e.max CAD IRFPDs, Group (3): BioHPP Granulates IRFPDs, and Group (4): breCAM.BioHPP IRFPDs. All IRFPDs were cemented using RelyX Ultimate adhesive resin cement. Samples were stored for 24 hours in distilled water at 37°C, and then thermocycled for 5000 cycles. Universal testing machine was used to measure fracture and dislodging loads. Samples were examined for determination of failure mode using a magnifying lens. Results: The statistically significant highest mean dislodging load value was obtained in IPS e.max Press IRFPDs, followed by IPS e.max CAD, with the least value recorded in breCAM.BioHPP. In contrast, breCAM.BioHPP IRFPDs revealed the statistically significant highest mean fracture load value, followed by BioHPP Granulates, while the least mean fracture value was recorded in IPS e.max Press. Most failure occurred in IPS e.max groups was connector fracture, while in BioHPP groups was plastic deformation. Conclusions: Retention and fracture resistance of metal-free inlayretained bridges are significantly affected by both; material type and construction method. BioHPP has significant advantages for dental applications because of higher fracture resistance and better stress distribution. The bond strength at IPS e.max/ resin cement interface is considered a reliable bond presenting better retention to IRFPDs. Being a brittle material, connector fracture is the predominant failure mode of IPS e.max IRFPDs; however, BioHPP has low elastic modulus showing plastic deformation as a predominant failure mode.
Purpose: The purpose of the current study was to assess fracture resistance and retention of three different endocrown materials. Materials and Methods: Thirty (n=30) sound mandibular molars were endodontically treated and according to endocrown constructed material appointed arbitrarily into 3 groups (n=10 each); Group (1): IPS e.max CAD, Group (2): Vita Suprinity and Group (3): Vita Enamic. Samples of each group were additionally subdivided into2 subgroups (n=5 each) according to fracture resistance and retention tests. Subgroup (A): Samples subjected to fracture resistance test and mode of failure. Subgroup (B): Samples subjected to retention test and mode of failure. The samples were thermocycled and seated on a universal testing machine and subjected to fracture resistance and retention test, then Data were statistically analyzed. Results: The highest mean failure load was recorded for Vita Suprinity endocrowns, followed by IPS e-max endocrowns, while Vita Enamic endocrowns recorded the lowest mean failure load.A non-statistically significant difference between the three tested groups of subgroup (A) revealed by using ANOVA test.The highest debonding load was recorded for Vita Enamic endocrowns, followed by IPS e-max CAD endocrowns, while the lowest mean debonding was recorded for Vita Suprinity endocrowns. A nonstatistically significant difference between the three tested groups of subgroup (B) revealed by using ANOVA test. Conclusions: Endocrowns of Vita Suprinity showed higher mean failure load value compared to endocrowns of E-max CAD and Vita Enamic. While endocrowns of Vita Enamic showed higher mean debonding load value compared to E-max CAD and Vita Suprinity.
purpose: The purpose of this study was to evaluate the effect of pattern construction technique on the marginal accuracy, internal fitness and fracture resistance of E-max crowns. materials and methods: Thirty caries-free human maxillary first premolars were selected, cleaned by scaling, and stored in 0.9% standardized saline solution at room temperature. Using an industrial lathe machine, the teeth were prepared to receive all ceramic crowns with standardized dimensions of 6 degrees angle of convergence. The preparation had 5mm occluso-cervical height, 6mm cervical diameter and 1 mm deep chamfer finish line. The prepared teeth were divided into three groups (n=10) according to the pattern fabrication techniques used: Group1: Conventional wax patterns. Group2: CAD/CAM wax patterns. Group3: 3D Printing of resin patterns. All patterns were invested to construct E-max crowns. The ceramic crowns were seated on their corresponding prepared teeth and the vertical marginal gap was measured with a binocular microscope (90X). Then internal gap of each ceramic crown was measured using the silicone replica technique. After cementation, each ceramic crown was statically, compressively and axially loaded until fracture at a cross head speed of 1 mm/min using a steel rod placed centrally at the occlusal surface of the crowns to evaluate the fracture resistance of the crowns. results: Group 1 showed the largest marginal gap mean (85.74±2.58μm) followed by group 2; (74.06±3.27µm) and then group3 (69.35± 3.44µm). These differences were statistically significant among the groups. The results of internal gap distances in group 1 (112±7.66µm) followed by group 2 (100±5.76µm) and then group3 (82± 7.2µm), the differences between the groups were statistically significant. The mean fracture resistance values of groups 1, 2 and 3 were 850.67±25.30N, 1080.01±47.06N and 1412.18±28.92N respectively. Post hoc test revealed that the differences between groups 1 and 2 as well as between groups 2 and 3 were statistically insignificant; however, the difference between groups 1 and 3 was statistically significant. Spearman's rank correlation coefficient showed value of-0.781. The negative sign indicates that the fracture resistance of the samples decreased as the internal gaps increased conclusions: The 3D printed pattern resulted in an E-max crown with better marginal adaptation and internal fitness. The fracture resistance of E-max crown was improved as its internal adaptation was enhanced.
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