Topic

[Prosthetics]  multi-unit abutment vs custom abutment


Hello Mark and Bernard,

     I hope you have had a great summer !

     I have a case ready for final impression at site # 46 and 47, but due to the deeper than normal periodontal pockets ( ~4 mm), I have been having poblems fitting the impression copings  without pinching the gingivae.I have tried lasering off the excessive tissue around the implant head, but still not successful. I am thinking ! Could I use a straight 3 mm multi-unit abutments over the implants to bring the final prosthesis above the gingivae, then take the final impression at that level?  . If it is reasonable to use the multi-unit abutment in this fashion, how does one decide when to use  custom  abutment vs multi -unit abutment ?   What criteria are we looking at ?

 

   Thank and look forward to your response !   

 p.s. : I have used the speedy external hex system in this case .

 

 

                                    Christina

        

 

             


by Christina Yee Min Wong at Thu, Sep 6, 2012 2:42 AM

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Christina Yee Min Wong Replied at Wed, Sep 26, 2012 12:01 AM

Dear Mark, Thanks ! I have done just that ( screw retained bridge with multi-unit abutments ). By the way, I have sent the photos with this case to your e-mail as per your request , did you received it ? - Christina



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Mark Kwon Replied at Tue, Sep 25, 2012 8:06 PM

Yes, normally it would be better to use custom abutments to reduce the number of interfaces. If you are intending on cement retained multiunits, then you are better of using custom cadcam abutments w long gigival heights. But, if you are intending on screw retained multiunits, it is difficult to seat properly all the way down to fixture level. Pt will definitely need to be frozen. If you are dealing with tissue depth beyond 5mm ie. 6mm or deeper in the posterior region , use of multiunit abutments to achieve screw retained multiunit restoration is a good idea. Hope this helps. - mark



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Christina Yee Min Wong Replied at Fri, Sep 7, 2012 12:55 AM

Hello, Mark, Thank you for the advice. Yes ! I will send you the X ray and photo next week, after I see the patient. What criteria, if any, do we use to decide whether to use a custom abutment or multi-unit abutment ? For example,in the case of deep perio tissue around the implant and we are able to to take final impression, then is it better to use custom abutment ? since there will be one less interface to have problem ? Is my line of thinking correct ? Thanks ! Christina



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Mark Kwon Replied at Thu, Sep 6, 2012 3:49 PM

Hi, Christina. That is a wonderful good question. This happened to me several times. This often happens in md 6 and 7 area near retromolar pads. Due to ascending ramus , the gingiva is often loose and rises up, resulting in deeper gingival pockets than you would like. The Answer is YES. You can use straight multiunit abutment to bring the margin level around 1mm below the gumline so that you can take abutment level impression. In fact, straight multiunit abutments were developed for restoring multiunit cases where draw would be problem. It allows clinician to over-come parallelism ie. draw and also to overcome deeper than usual tissue depth. One thing you must remember is that the two crowns must be fused!! Because multiunit abutments are non-engaging they must be fused, otherwise will come loose! PS. Christina Could you please send me x-ray and or photo of this case? I would like to use them to make a video casting for the members. thx. - mark