Prosthodontips – resin-retained bridges: fun and predictable

In this month’s Prosthodontips, Josh and Zo take a closer look at RRBs and how to create a favourable long-term solution for a patient.

Resin-retained bridges (RRBs) have been around for decades. However, despite the favourable evidence from long-term clinical studies, they have developed a rather undeserved reputation for failure. Perhaps this is because many people see them as technique-sensitive and difficult to handle. Others may struggle to get the best out of these versatile restorations simply because they are unsure how best to use them.

This month, we will address the use of RRBs through the use of a case study. Not much text to read, lots of photos and a very happy patient at the end.

Let us know what you think and if you would prefer this format in the future! Enjoy!

RRB case study

Figure 1: UR3 missing on presentation. This patient wanted to avoid treatment with implants due to medical and social complications. It seemed Figure 2 An occlusal view shows that the patient has a moderately restored dentition and is partially dentate. Most of the really important teeth are present. Her occlusion was also favourable and this is first positive indicator for success in this case. There is also a visible defect labially at the UR3 extraction sitea little excessive to consider preparing the adjacent teeth for a conventional FPD and a partial denture was also ruled out. Hence, the resin-retained bridge became the obvious choice
Figure 2: An occlusal view shows that the patient has a moderately restored dentition and is partially dentate. Most of the really important teeth are present. Her occlusion was also favourable and this is the first positive indicator for success in this case. There is also a visible defect labially at the UR3 extraction site
Figure 3: These images are easy to annotate and I use an iPad for this. The patient can then easily see what I am talking about and it is recorded for future reference. By doing this, it also ensures that I have not missed anything and I sleep easier at night
Figure 4: More of the same. Here I am starting to identify things that are going potentially detract from the final outcome and making my patient aware of the limitations of what can be achieved. All of this is really important in the build up to the final result. Identifying these things early on really helps to reduce stress later
Figure 5: Extra-oral view. It really should be obvious why this patient wants a tooth in there. Identifying the patient's motivation for treatment is another key element in consistently achieving successful outcomes
Figure 6: I use facebows quite a lot, especially where there is potential for restorations to be dislodged. We are replacing a canine in this case, usually one of the longest teeth in most patients. There is generally lots of opportunity for this tooth to get pushed around during mandibular movements. The occlusion was favourable in this case, but I was just more comfortable knowing that we were not taking any chances. It also helps to line things up aesthetically
Figure 7: I use a relatively fast-setting silicone on the bite fork when taking a facebow registration. I use as little as possible and even the amount shown here is probably a little bit excessive. Sometimes less is more
Figure 8: This is a milled PMMA protype restoration. It is completely representative of the definitive restoration. It allows myself and the patient to assess things functionally and aesthetically before we proceed. I use a temporary cement to place it in situ during evaluation. A pencil has been used to colour the abutment wing black so the patient can figure out what the metal may look like in her mouth
Figure 9: Another view of the PMMA prototype bridge. Those black triangles are becoming obvious now. Good thing our patient is already expecting them
Figure 10: A photograph showing the fitting surface of the PMMA prototype bridge
Figure 11: Occlusal view of the protoype bridge in situ at UR3. Note the pencil colouring of the abutment wing to simulate the definitive restoration
Figure 12: Shade matching is critical in this area. Canines are generally a little dark and/or more yellow than the other maxillary anterior teeth
Figure 13: I tend not to give an exact shade to my lab technician. I usually take a couple of photographs with the relevant tabs and ask them to use their artistic flair to make things look nice and natural. The upside is I get beautiful restorations at the end. The downside is that it sometimes takes us ages to get there
Figure 14: Close up of my definitive impression. A minimal preparation was carried out to eliminate a mesial undercut on the UR4. A heavy and light body PVS impression was ultimately taken
Figure 15: Occlusal view of the working model with the definitive restoration in position. It is really important to get the lab work back in advance of the try-in day to ensure everything looks good. In this case I was happy the lab had followed my prescription. Often it needs to go back for further modifications. Don’t be afraid to do this…your patients will love you for it
Figure 16: This photo was taken by the technician. It's a simple thing to do to check how the shade matching is coming along before he sent the work back to me. It gives me an indication of how things are going as well
Figure 17: Look really carefully. Here, the fitting surface of the abutment wing has not been completely sandblasted. There are contaminants on the surface and it just is not right for optimal bonding. Look at it with your loupes or take a picture like I did. A quick once over with the sandblaster and it’s good to go
Figure 18: Aaaaah finally! It's in!
Figure 19: Like I said at the start...thats one happy patient. All the little things along the way ensured this result was going to be a hit from the word go. No theatrics, no magic and certainly nothing special. Just a bit of attention to detail and passion for what you are doing

Please keep the questions coming for the Prosthodontips team. You can contact us on Instagram (@sharplingdental and @prostho_zo) and also email (prosthodontips@googlemail.com).

If there are specific topics you would like us to cover in a column, please let us know.

Previous Prosthodontips:

Follow fmc-stage.thinkdemo.co.uk on Instagram to keep up with all the latest dental news and trends.