The Practical Research On The Integration Of Cercon All-ceramic Crown And TA₂ Pure-titanium Implant Abutment

The all-ceramic restorations have been widely accepted because of there superb and natural aesthetic effects, and the importance of the aesthetic properties of implant superstructures has been more and more emphasized. At present, PFM crowns cemented or screw-retained to the abutments are most commonly used as restorations of implant superstructure. However, the poor aesthetic properties of PFM crowns and possibly revealable metal abutments near the gingival region compromise the aesthetic and long-term restoration effects, and the inconvenient and undetachable retention make the implant vulnerable to perioimplant diseases. The use of the all-ceramic crown and the integration of all-ceramic crown and titanium abutment not only greatly improve the aesthetic properties of both crown and gingival tissue, but also gain many integrated advantages and individualized properties. This method could establish a sound basis of long term stability of implant restorations.In this research, in order to resolve the problems mentioned above, integrative components of implant superstructure are designed in light of aesthetic, mechanical and biological requirements. The TA₂ pure titanium abutments that match a certain implant system are fabricated by precise machining, and the integration is obtained by fusing the Cercon all-ceramic crowns to the abutmentsby TiBond ceramic. The aesthetic advantages of Cercon all-ceramic system result in the natural and excellent appearance of both crown and gingival region. The integration eliminates the interspace between crowns and abutments, resolves the problems of cemented retention, makes maintenance easier and ensures long-term success of implant restorations. In this research, by simulating test and clinic trial, employing mechanic and chromatological means, scanning electronic microscope, electronic probe micro-analysis, the characteristics of surfaces of integrated restorations, the aesthetic properties, the influences of metal abutment on the color of all-ceramic crowns, the oxidation state of TA2 pure titanium and the match between our own-made abutment and the ready-made implant system are thoroughly explored. The long term restoration effects are assessed by follow-up study. The practicability of integrated implant superstructure is evaluated by all-rounded study.Results show that the own-made abutments match precisely with the ready-made implant system and meet the aesthetic, mechanic and biologic requirements. The gap between abutments and the implants is less than 10 um. The binding strength is 56.28Mpa for ZrO2-Cercon Ceram S interface, 45.66Mpa for TA2-Tibond interface, 48.71 for TA2-TiBond interface and 68.79 for ZrO2-TiBond-TA2 interface respectively. These values could meet the clinical requirements. The integration has the aesthetic advantage of all-ceramic system and restores natural appearance of human teeth. The test on the opacity of Cercon Ceram S and TiBond shows, for both ceramic, the thickness of opaque is less than 0.2mm when AE=1.5. After fusing 0.2mm opaque to the surface of Z1O2, the AE of the white and dark background is less than 1NBS. Thus the metal post or the implant abutment would not compromise the aesthetic properties of all-ceramic crown. The integration has sound clinic success rate and contributes to the health and aesthetics of perioimplant gingival tissues. Also, the integration is easily operated and clinically practical.This research provides experimental evidences for the practicability of design and fabrication of individualized integrated abutment that matches precisely with the ready-made implant system. It also provides theoretical basis and experimental parameters for the application of Cercon all-ceramic system in the fields of metal post -core restoration, implant superstructure and crown-abutment integration. It suggests a new restoration means of implant superstructure that meets aesthetic requirements of both crown and gingival tissue, ensures long term success rate and easy to fabricate. Limited by the time, the clinical application of this research is short term. Nevertheless, it provides many valuable clinical experiences as well as establishes groundwork for the further study on this integration method.