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					                                                                                                                                                Handout # 10



                      Advantages of Cement Verses
                   Screw-Retained Implant Prostheses
1)          Discrepancies in fit of the castings to the abutments are negated by the grouting action of the
            cement.
2)          Non-passive frameworks are seated and adjusted by the use of routine chair-side clinical
            procedures and indicating materials.
3)          Sectioning and soldering is not a routine procedure as it is for screw-retained castings.
4)          The lack of screw holes in cemented prostheses provides a design that enhances the physical
            strength of porcelain and acrylic resin, resulting in fewer fractures.
5)          The occlusal surface is devoid of screw holes and, as such, occlusion can be developed that
            responds to the need for axial loading.
6)          Cement-retained implant prostheses provide easier access to the posterior of the mouth, reduced
            costs, reduced complexity of components, reduced complexity of laboratory procedures, and
            reduced chair-side time.
7)          Cement-retained prostheses have superior esthetics, which is important from the patient’s
            perspective.
8)          Prostheses cemented over accurately fitting machined abutments established a more stable and
            passive environment than screw-retained castings with micro gaps and unfavorable loading
            characteristics.
9)          The anatomic surfaces of all the teeth are present to develop protrusive and lateral protrusive
            relationships that are not interfered with by the screw retention configuration.

      Reference
      H E B E L, K S , G A J J AR , R C C e m e n t - R e t a i n e d I m p l a n t R e s t o r a t i o n s : A c h i e v i n g O p t i m a l
      Occlusion And Esthetics in Implant Dentistry.
      Prosthetic Dent J 1997; 77; 28 -34

                                                         __________________________

10)         A cement-retained prosthesis offers the advantage of using the cement layer of 25 to 50 microns
            as prosthetic compensation for casting inaccuracy.
11)         Proper relief of the castings will allow a passive fit over the implant-abutment posts.

12)         Significant tensile or compressive forces to the implant complex due to minor casting
            inaccuracies are essentially eliminated by this technique.
13)         Cement-retained restorations have significant structural advantages over screw-retained
            restoration when the weakest component (the screw) of the implant restoration is considered.



                                                                                                                                                    07 Oct 06
14) Selection of cement retention converts an implant prosthesis into a conventional prosthesis,
    where familiar skills and techniques can be used to produce an acceptable restoration.
15) Cement-retained restorations can be made using direct impression techniques with as few as
    one component, the prosthetic post.
16) Cement-retained restorations offer more flexibility to achieve optimal esthetics as compared
    with screw-retained systems.
17) Optimum occlusal integrity is maintained by the intact occlusal surface of the cement-retained
    restoration.
18) Provisional restorations for cement-retained prostheses may be fabricated in a manner similar
    to that of natural teeth, offering a savings in component costs and time.


Reference
DARIO, LJ Implant Angulation And Position And Screw Or Cement Retention: Clinician Guidelines
Implant Dent. 1996; 101-103.




                                         Robert D. Westerman, D.D.S., Ltd .
                                              7931 Jefferson Highway
                                           Baton Rouge, Louisiana 70809
                                                   (225) 927-3442


                                                                                                07 Oct 06

				
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