Yazar "Güven, Mehmet Esad" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Dimensional Stability of Additively Manufactured Diagnostic Maxillary Casts Fabricated with Different Model Resins
    (Quintessence Publishing Co. Inc., 2024) Dönmez, Mustafa Borga; Wepfer, Alena Bruna; Güven, Mehmet Esad; Çakmak, Gülce; Schimmel, Martin; Yılmaz, Burak
    Purpose: To evaluate the effect of model resin type and time interval on the dimensional stability of additively manufactured diagnostic casts. Materials and Methods: Ten irreversible hydrocolloid impressions and 10 impressions from an intraoral scanner were made from a reference maxillary stone cast, which was also digitized with a laboratory scanner. Conventional impressions were poured in type III stone (SC), while digital impressions were used to additively manufacture casts with a nanographene-reinforced model resin (GP) or a model resin (DM). All casts were digitized with the same laboratory scanner 1 day (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), and 4 weeks (T4) after fabrication. Cast scans were superimposed over the reference cast scan to evaluate dimensional stability. Data were analyzed with Bonferroni-corrected repeated measures ANOVA (α =.05). Results: The interaction between the main factors (material type and time interval) affected anterior teeth deviations, while the individual main factors affected anterior teeth and entire-cast deviations (P ≤.008). Within anterior teeth, DM had the lowest deviations at T3, and GP mostly had lower values at T2 and lower deviations at T3 than at T0 (P ≤.041). SC had the highest pooled anterior teeth deviations, and GP had the highest pooled entire cast deviations (P <.001). T3 had lower pooled anterior teeth deviations than at T0, T1, and T4, and higher pooled entire cast deviations than T1 were demonstrated (P ≤.027). Conclusions: The trueness of nanographene-reinforced casts was either similar to or higher than that of other casts. Dimensional changes were acceptable during the course of 1 month. © 2024 by Quintessence Publishing Co Inc.
  • Küçük Resim
    Öğe
    Fatigue behavior of implant-supported cantilevered prostheses in recently introduced CAD-CAM polymers: An in vitro study
    (Elsevier Inc., 2024) Dönmez, Mustafa Borga; Çakmak, Gülce; Güven, Mehmet Esad; Dede, Doğu Ömür; Abou Ayash, Samir; Yılmaz, Burak
    Statement of problem: Cantilevered complete arch implant-supported prostheses are commonly fabricated from zirconia and more recently from strength gradient zirconia. Different polymer-based materials indicated for definitive fixed prostheses that could be used with additive or subtractive manufacturing have also been marketed recently. However, knowledge on the long-term fatigue behavior of cantilevered implant-supported prostheses made from these polymer-based materials and strength gradient zirconia is lacking. Purpose: The purpose of this in vitro study was to evaluate the fatigue behavior of implant-supported cantilevered prostheses of recently introduced computer-aided design and computer-aided manufacturing polymers and zirconia. Material and methods: A master standard tessellation language file of a 9×11×20-mm specimen with a titanium base (Ti-base) space that represented an implant-supported cantilevered prosthesis was used to fabricate specimens from additively manufactured interim resin (AM), polymethyl methacrylate (SM-PM), nanographene-reinforced polymethyl methacrylate (SM-GR), high-impact polymer composite resin (SM-CR), and strength gradient zirconia (SM-ZR) (n=10). Each specimen was prepared by following the respective manufacturer's recommendations, and Ti-base abutments were cemented with an autopolymerizing luting composite resin. After cementation, the specimens were mounted in a mastication simulator and subjected to 1.2 million loading cycles under 100 N at 1.5 Hz; surviving specimens were subjected to another 1.2 million loading cycles under 200 N at 1.5 Hz. The load was applied to the cantilever extension, 12-mm from the clamp of the mastication simulator. The Kaplan–Meier survival analysis and Cox proportional hazards model were used to evaluate the data (α=.05). Results: Significant differences in survival rate and hazard ratio were observed among materials (P<.001). Among tested materials, SM-ZR had the highest and AM had the lowest survival rate (P≤.031). All materials had a significantly higher hazard ratio than SM-ZR (P≤.011) in the increasing order of SM-GR, SM-PM, SM-CR, and AM. Conclusions: SM-ZR had the highest survival rate with no failed specimens. Even though most of the tested polymer-based materials failed during cyclic loading, these failures were commonly observed during the second 1.2 million loading cycles with 200 N. All materials had a higher hazard ratio than SM-ZR. © 2024 The Authors