In-Vitro Comparison of Implant-Supported Single Crowns and Abutments Manifactured with Different Techniques
Project no. 21675 · Status: Kapanmış (Yayın bekleniyor) · 2020
Summary
İmplant-supported prosthetic restorations stand out as a frequently used treatment protocol contemporarily, especially for the single missing tooth. The long-term clinical success of implant-supported prosthetic restoration is directly related to the right indication and surgical application, as well as the suitable prosthetic planning for the case. Within the scope of right prosthetic planning, the properties of the superstructural components should also be carefully selected. Accordingly, the selection of the abutment and superstructure design is crucial. The long-term success of the restoration increases when the abutment material and manifacture technique are taken into consideration. The complications seen can be minimized by choosing the proper abutment and superstructure design. Of the late years, modified hybrid restorations in which the abutment and superstructure crowns are manifactured as one piece and screwed to the implant are referred to as “hybrid-abutment-crowns”. It is stated that this design, which combines the advantages of cement-retained and screw-retained implant-supported restorations, positively affects the long-term clinical success of the restorations. However, there is lack of information in the literature about the design in question. In this study, the fracture strength and screw loosening rate of implant-supported single crown restorations manifactured with different materials and different techniques are evaluated. For this purpose, a total of 40 implants are divided into 4 groups. Restorations in the first group consist of prefabricated titanium abutment supported screwmentable crowns prepared by cementing titanium-based-porcelain crowns on prefabricated titanium abutments and screwing the cemented crowns to the implants. Restorations in the second group consist of prefabricated zirconia abutments supported screwmentable crowns prepared by cementing zirconia-based-porcelain crowns on prefabricated zirconia abutments and screwing the cemented crowns to the implants. The third group is monoblock titanium hybrid-abutment-crowns produced by the veneer porcelain baked directly on titanium representative abutments manifactured individually by CAD/CAM. The fourth and last gruop consist of monoblock zirconia hybrid-abutment-crowns produced by the veneer porcelain baked directly on zirconia representative abutments manifactured individually by CAD/CAM and bonded to Ti-bases. Following the thermocycle process, screw loosening ratios of the abutment screws of the restorations produced with different techiques and materials were first determined by measuring the removal torque values (RTV), afterwards the fracture strength of the restorations were measured and failure modes were examined. No statistically significant relationship was found between the abutment material and screw loosening. Screw loosening rates were %20,09?6,49; %15,23?6,07; %11,63?7,48 and %9,59?8,84 for titanium hybrid-abutment-crowns, zirconia screwmentable crowns, zirconia hybrid-abutment-crowns and titanium screwmentable crowns respectively. It has been determined that the manifacture technique and superstructure design of the abutment is not a factor affecting the screw loosening for zirconia abutments. The group with the highest screw loosening ratio was determined as the titanium hybrid-abutment-crown group and the group with the lowest was the titanium screwmentable crown group. Only the difference between the screw loosening values of these two groups was found statistically significant. It has been observed that; abutment material, manifacture technique and superstructural design affect the fracture strength of the restorations. The fracture strength of hybrid-abutment-crowns were determined higher than conventional screwmentable crowns and found that the manifacturing of the system in one piece instead of two pieces increases the fracture strength. It has been determined that the fracture strength of the abutments manifactured from titanium in both the hybrid-abutment-crown and screwmentable crown groups were significantly higher than zirconia. The group with the highest fracture strength is the titanium hybrid-abutment-crown group with 385,84?27,68 N. This group is followed by 313,18?39,97 N; 272,69?35,03 N and 156,71?19,83 N for the zirconia hybrid-abutment-crown group, titanium screwmentable crown group and zirconia screwmentable crown group respectively. The differences between the mean fracture strength of the groups were found to be statistically significant.