Yazar "Gumus, Hilal Siriner" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Evaluation of fracture resistance of inlay-retained fixed partial dentures fabricated with different monolithic zirconia materials
    (Mosby-Elsevier, 2018) Gumus, Hilal Siriner; Polat, Nilufer Tulin; Yildirim, Guler
    Statement of problem. Data are lacking on the fracture resistance of monolithic zirconia inlay-retained fixed partial dentures as a conservative treatment for a single missing tooth. Purpose. The purpose of this in vitro study was to evaluate the fracture resistance of inlay-retained fixed partial dentures produced from 3 different monolithic zirconia materials and based on 2 preparation types and applications with and without thermocycling. Material and methods. A model with missing right and left mandibular first molars was used for different cavity preparations. A tube-shaped cavity and a box-shaped cavity were prepared. Seventy-two epoxy resin casts were prepared from an additional silicone impression. Twenty-four inlay-retained fixed partial dentures from each monolithic zirconia material (Prettau, Zirkonzahn; Katana, Noritake; and Copran, Whitepeaks) were fabricated for each preparation type and cemented to their epoxy model with dual-polymerizing adhesive resin cement; 50% of all specimens were thermocycled for 10 000 cycles. The specimens were subjected to a fracture resistance test using a universal testing machine with a crosshead speed of 0.5 mm/min. Fracture surfaces were examined with scanning electron microscopy (SEM), and a specimen from each group was examined for structural changes with differential thermal analysis (DTA). Results. No statistically significant differences in terms of fracture resistance were found among brands with both cavity designs and with and without thermal cycles (P>.05). However, SEM and DTA results showed some changes in monolithic zirconia structure after 1 year of aging. Conclusions. The brands and cavity preparation types for single posterior tooth loss generated similar fracture resistance.
  • Küçük Resim Yok
    Öğe
    Evaluation of the marginal and internal gaps of partially crystallized versus fully crystallized lithium disilicate CAD-CAM crowns
    (Springer, 2026) Gumus, Hilal Siriner; Aygun, Esma Basak Gul; Tuzlali, Mesut; Dogan, Nazli Totik
    This in vitro study aimed to evaluate the internal and marginal adaptation of crowns produced from partially crystallized and fully crystallized lithium disilicate CAD-CAM blocks using direct view and the silicone replica method. The mandibular first molar was used as an abutment. A total of twenty crowns (n = 10) were produced using milling CAD-CAM. The direct viewing technique was used to measure the marginal gap. The measurement of internal adaptation was conducted using the silicone replica technique. Following the subsequent glazing procedure, all crowns underwent another round of measurements. The paired samples t-test was used to compare two related continuous variables. The study revealed that the mean value of the marginal gap of the partially crystallized block is significantly higher than the fully crystallized block both before and after the glazing process. A statistically significant difference was found before and after glazing of the partially crystallized block in the marginal gap values. The fully crystallized crowns showed better marginal gap values than the partially crystallized ones. No change was observed before and after the glaze in the fully crystallized block. The recommended limit of 120 mu m for the marginal gap of lithium disilicate CAD-CAM crowns was never exceeded.