Browsing by Author "Fahmy, Nadia"

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Effect of Different Glass-Ceramics and Resin Cement Curing Modes on the Color Stability of Sectional Laminate Veneers Following Artificial Aging
(October university for modern sciences and Arts MSA, 2023-01) Mohamed, Abdallah; Naguib, Alaa; Fahmy, Nadia
kground: The purpose of this study is to evaluate the effect of two glass ceramic materials and resin cement curing modes on the color stability of sectional porcelain laminate veneers following artificial aging. Methods: Forty sound human maxillary central incisors were prepared to receive sectional laminate veneers (SLVs) with a thickness of 0.5-0.7 mm. Prepared teeth were randomly divided into 2 equal groups according to ceramic materials used (N=20) as follows: Group I: IPS e.max press. Group II: Celtra press. Each main group was randomly subdivided into 2 equal subgroups according to resin cement used: light and dual cure resin cements (Relyx Veneer) (Relyx Ultimate) respectively. All samples were subjected to 10,000 cycles of thermo-cycling. Color change was measured by laboratory spectrophotometer before and after thermocycling. All the collected data were statistically analyzed by One-way ANOVA followed by Tukey’s post hoc test. Results: Color change between restoration and natural side of each sample before and after artificial aging did not reveal significant difference (P<0.05). IPS e.max press showed significant lower color stability with dual and light cure resin cement (ΔE 3.48- ΔE 3.4) than Celtra press (ΔE 2.6- ΔE 3.05). Light cured resin cement used with Celtra press showed statistically significant higher ΔE value than dual cured cement (P>0.05). Conclusions: Celtra press glass ceramic is more color stable than IPS e.max press. Resin cement and aging process influenced the color stability of sectional laminate veneers. Results were clinically accepted for all tested materials in reference to natural teeth (ΔE<3.5). The results may help the patient to aesthetically correct their anterior teeth with a suitable material providing strength and natural teeth looking, in addition to conservation of tooth structure, with optimum esthetics.
The effect of different materials and cavity designs on fracture resistance of ceramic partial coverage
(Wiley-Blackwell, 2024-07) Attia, Mahmoud; Fahmy, Nadia; Shaker, Atef; Salah, Tarek
Background: Two intra-coronal preparation designs with varying extensions of cuspal coverage can perform differently regarding their fracture resistance against introral forces. Methods: Two materials (IPS e-max CAD [EX], VITA ENAMIC [EN]), and two different preparation designs (EX-D1), (EX-D2), (EN-D1), and (EN-D2) were investigated to compare their fracture resistance. A total of 40 (n = 40) caries free human mandibular molars were used. All the prepared samples were scanned using CEREC Omnicam scanner and the preparations were checked by the software for any sharpness and undercuts before restoration designing and fabrication. All restorations were milled using Cerec MCXL 4.4 milling machine. Duo-Link resin cement was used for cementation. After thermocycling and chewing simulation, all samples were loaded in the Universal testing machine in order to evaluate fracture resistance of all samples. Results: Fracture resistance testing revealed that e-max CAD (2134 N) showed statistically significantly higher mean fracture resistance values than Vita Enamic (1728 N). On the other hand, there was no statistically significant difference between mean fracture resistances between the two tested designs. Conclusions: Within the confines of this investigation, it can be said that although preparation design had no appreciable impact on fracture resistance, the CAD/CAM ceramic material utilized did. Clinical Significance: When restoring compound cavitties indirectly; a conservative defect oriented approach should be used. Glass Ceramic are prefered as restorative material.
Fracture Resistance of Different Designs of a Resin-Bonded Fixed Dental Prosthesis: An In Vitro Study
(QUINTESSENCE Publishings, 2021-04) Naguib, Alaa; Fahmy, Nadia; Hamdy, Amina; Wahsh, Marwa
Purpose: To evaluate the effect of three two-retainer designs of a resin-bonded fixed dental prosthesis (RBFDP) on fracture resistance. Materials and methods: A total of 21 three-unit, all-ceramic RBFPDs were fabricated to replace a missing maxillary lateral incisor. The prostheses were divided into three groups of 7 each: Group L (labial RBFPD); Group ML (modified labial RBFPD, fabricated the same as in Group L with additional preparation that included a shallow proximal groove at the pontic side); and Group P, an all-ceramic palatal RBFPD that acted as control. Preparations were done on the maxillary left central incisor and canine of a typodont model, and 21 epoxy resin models were duplicated for the three groups. The RBFPDs were designed using CAD software and constructed using the heat-pressed technique, after which the prostheses were bonded to their corresponding epoxy resin model according to the manufacturer's instructions. A fracture resistance test was performed on all specimens following aging. Data were analyzed using one-way ANOVA. Results: The highest fracture load values were recorded in Group P (547.5 N), followed by Group ML (462.6 N) and then Group L (418.3 N). The difference among the three designs was not statistically significant (F = 2.5, P = 0.1). Conclusion: Both labial and modified labial RBFDPs could be a viable alternative treatment option for replacement of missing maxillary lateral incisors.