Yazar "Vallittu, Pekka K." seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Effects of Different Cavity Designs on Fracture Load of Fiber-reinforced Adhesive Fixed Dental Prostheses in the Anterior Region(Quintessence Publishing Co Inc, 2013) Aktas, Guliz; Basara, Emine Goncu; Sahin, Erdal; Uctasli, Sadullah; Vallittu, Pekka K.; Lassila, Lippor V. J.Purpose: To evaluate the fracture strength of inlay-retained, surface-retained, and cantilevered fiber-reinforced adhesively fixed dental prostheses (FRA-FDPs) in the anterior region. Materials and Methods: Thirty-two sound human right central incisors and canines were divided into four groups. Test groups were as follows: group 1, both teeth had deep cavity preparation; group 2, both teeth had shallow cavity preparation; group 3, only the canine teeth had deep cavity preparation; group 4, no preparation was made on the abutment teeth. Lateral pontics were restored with FRA-FDPs. All restorations were subjected to fracture loading from the lateral pontic. The restorations were tested in a universal testing machine (LRX Material Testing Machine) with a crosshead speed of 1 mm/min. One-way ANOVA was used for statistical analyses. Fracture modes were examined visually. Results: The highest (667.3 +/- 90.4 N) and the lowest (409.3 +/- 158.1 N) debonding values were found for groups 4 and 3, respectively. Conclusions: Different preparation designs (inlay-retained, surface-retained) had no significant effect on fracture strength of FRA-FDPs in the anterior region. However, a cantilever design exhibited significantly lower fracture strength. Delamination of the veneering composite was observed as the primary failure type after fracture tests.Öğe LOAD BEARING CAPACITY OF FIBER-REINFORCED AND UNREINFORCED COMPOSITE RESIN CAD/CAM-FABRICATED FIXED DENTAL PROSTHESES(Mosby-Elsevier, 2013) Basaran, Emine Goncu; Ayna, Emrah; Vallittu, Pekka K.; Lassila, Lippo V. J.Statement of problem. It is unclear if fiber-reinforced fixed dental prostheses can be fabricated with physical properties that make them suitable for definitive prostheses. Purpose. The purpose of this study was to compare the load bearing capacity of fiber-reinforced and unreinforced computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated fixed dental prostheses. Material and methods. Fixed dental prostheses were fabricated with CAD/CAM from 3 experimental fiber-reinforced composite resin blocks, 1 experimental composite resin block, and 1 commercially available composite resin block. The experimental fiber-reinforced composite resin was prepared by mixing dimethacrylate resin with filler particles of BaO silicate and E-glass fiber. Different ratios of resin, filler, and fiber were used to fabricate specimens measuring 15.5 x 19 x 39 mm, which were allocated to 5 different groups (n=8) and statically loaded until final fracture. Statistical analyses were calculated according to final fracture values. A 1-way ANOVA and the Tukey post hoc multiple comparison test were used (alpha=.05). Results. All groups showed significantly different load-bearing capacities (P<.001). Experimental randomly oriented fiber-reinforced composite resin blocks revealed the highest load-bearing capacity (2163 +/- 246 N), whereas commercial composite resin blocks showed the lowest (1290 +/- 172 N). Conclusions. Fixed partial dental prostheses consisting of experimental fiber-reinforced composite resin blocks showed higher load-bearing capacities than did unreinforced composite resin blocks. (J Prosthet Dent 2013;109:88-94)Öğe Load-bearing capacity of fiber reinforced fixed composite bridges(Taylor & Francis Ltd, 2013) Basaran, Emine Goncu; Ayna, Emrah; Li, Sadullah Uctas; Vallittu, Pekka K.; Lassila, Lippo V. J.Objective. The aim of this study was to evaluate the reinforcing effect of differently oriented fibers on the load-bearing capacity of three-unit fixed dental prostheses (FDPs). Materials and methods. Forty-eight composite FDPs were fabricated. Specimens were divided into eight groups (n = 6/group; codes 1-8). Groups 1 and 5 were plain restorative composites (Grandio and Z100) without fiber reinforcement, groups 2 and 6 were reinforced with a continuous unidirectional fiber substructure, groups 3 and 7 were reinforced with a continuous bidirectional fiber and groups 4 and 8 were reinforced with a continuous bidirectional fiber substructure and continuous unidirectional fiber. FDPs were polymerized incrementally with a handheld light curing unit for 40 s and statically loaded until final fracture. Results. Kruskal-Wallis analysis revealed that all groups had significantly different load-bearing capacities. Group 4 showed the highest mean load-bearing capacity and Group 7 the lowest. Conclusion. The results of this study suggest that continuous unidirectional fiber increased the mechanical properties of composite FDPs and bidirectional reinforcement slowed crack propagation on abutments.Öğe Load-bearing capacity of handmade and computer-aided design-computer-aided manufacturing-fabricated three-unit fixed dental prostheses of particulate filler composite(Taylor & Francis Ltd, 2011) Basaran, Emine Goncu; Ayna, Emrah; Vallittu, Pekka K.; Lassila, Lippo V. J.Objective. To compare handmade and computer-aided design-computer-aided manufacturing (CAD-CAM)-fabricated fixed dental prostheses (FDPs) composed of a particulate filler composite. Material and methods. Handmade FDPs were made of restorative composite (Z 100) and CAD-CAM-fabricated FDPs were made of commercial CAD-CAM blocks (VITA Temp) and two experimental CAD-CAM blocks of particulate filler composite. Experimental CAD composite A was prepared by mixing 31.2 wt.% of dimethacrylate resin with 68.7 wt.% of filler particles of barium oxide silicate (BaSiO2). Experimental CAD composite B was prepared by mixing 25.6 wt.% of dimethacrylate resin with 74.3 wt.% of filler particles of BaSiO2. Six groups were fabricated (n = 6 in each); FDPs were statically loaded until final fracture. Results. Experimental CAD composites A and B revealed the highest load-bearing capacity of the FDPs, while Z 100 showed the lowest. Conclusion. FDPs made of experimental CAD composite blocks showed higher load-bearing capacities than handmade commercial composites and commercial blocks.
