Dr. Beatrice Leung Dentistry Professional Corporation

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A Very Difficult Cast RPD….


With today’s technology and materials, when I see a compromised dentition, It is always easy to think of many treatment possibilities.  Whether it is full mouth clearance and to consider one of the implant supported solutions or to save all teeth and to plan and perform a full mouth reconstruction, there are many ways to save teeth or not to save teeth.

However, when you are caught in the middle and the patient does not have all the funds to support either extreme treatment options, I am left with the obligation to provide the most sensible solution and yet hopefully aesthetically and functionally acceptable to the patient….Sometimes, this is where it gets fun for me…because it allows me to think a little harder and try a little harder to make something work for the patient.

I fabricated a cast RPD for this patient.  I know to some people, this is just an RPD…but to me, this was a very difficult one on many levels.  I thought I should share what was difficult for me for this case.


1/The patient has an anterior open bite with only localized posterior occlusal contacts.

2/Most of the abutments are lingually tipped and heavily restored and have a history of periodontal bone loss

3/Multiple modifications spaces with two lone standing abutments making me think long and hard how to design this RPD with proper retention, resistance and stability.

4/There is also an aesthetic component with the multiple missing anterior teeth.

What I did:

1/Always start with a diagnostic teeth arrangement to visualize the end point.

With multiple lone standing abutments and anterior missing teeth, I have to decide how many and what size of denture teeth to fit into these edentulous spaces….Notice, I decided to use only three anterior teeth  between the two canines…I also told the patient there will be no occlusion in the anterior segment.

2/Surveying for a favourable path of insertion.

I have to look at two things here: Anterior posterior path to ensure I minimize the black triangle spaces of the anterior abutment if possible….I also look at buccal lingually to ensure I have favourable undercut for retention.  In this case, I have to incorporate principles of rotational path RPD.  The denture has to be seated anterior first and the right side partially first before it can be rotated to seat the left side completely.

3/Taking impression was very challenging

With the amount of bone loss, recession, interproximal undercut, and the need to capture so much information on so many abutments, I needed a custom tray to ensure I cover the entire arch adequately.    I also used an impression material that is less rigid.  I used light body PVS in this case.

4/Not using the implants for retention.

You may notice that the patient has two existing implants on the lower right. They were originally planned for fixed implant restorations.  I was hoping I can use them for the RPD.  However, after looking at the path of insertion and the adjacent abutments, the mechanics of implant abutments will not work favourably with conventional clasp mechanics.  I decided to use them for support only with no active retentive elements.

5/Expect a difficult metal framework try in. 

In this case, I knew, based on the design and the nature of the abutments, this would not be an easy framework try in appointment.  I expected the impression to distort a bit more than my other cases and despite the lab doing a good job with making the casting, I still had to spend quite a bit of time adjusting this framework.  However, once it is adjusted, I was quite happy with the fit.

Once I got the framework to fit, than it gets a lot easier. However, on insertion, I still did end up making more adjustment to the framework and the acrylic to ensure that the patient can insert and remove the partial denture without any difficulty.

The patient actually did not have much post insertion discomfort after one to two weeks of wearing the denture.  It was more  of learning how to insert and remove the denture that took some time.  He also needs to ensure to keep up with his proper home care.  With the amount of root exposure, proper plaque control is always a challenge.

Cast RPD can be very versatile.  It can be a cost effective method to replacing many missing teeth. In some cases, by providing an apron design, it can help stabilize the periodontally weak abutments and may prolong the life span of these teeth.

I hope by sharing this case, you have gained new understandings on RPD treatment.   Thanks for reading!

Special thanks to Jeff Luk from Shaw Lab on the laboratory support.