Pre-existing crowns for RPD

60 year old female partially edentulous patient wanted to restore her teeth, the 1st and 2nd quadrant were missing, Implants are not a viable option for her as she has severe bone loss, I want to do RPD for lower, the problem is that the maxillary remaining teeth all have crowns. I do not want to remove the crowns nor does the patient want that. Can I place the RPD abutments on pre-existing crowns without making new ones?

Tim comments:

If you are referring to placing rest seats the yes you can place them on the existing crowns. If you are concerned about the thickness of the crowns once you prepare them then you can do conventional amalgam preps within the crowns and create the rests in amalgam. No need to complicate it.

Matt Helm DDS comments:

"No need to complicate it", you say? 'Course not, because you've already complicated it beyond comprehension, and certainly way beyond the realm of anything normal. WHERE IN THE WORLD did you ever get that hair-brained idea, dear "colleague"?!? (The quotation marks are appropriate because I shudder to think that the likes of you could actually be my colleague). Have you ever considered the sheer HARM you might do to an otherwise perfectly good bridge AND SUPPORTING ABUTMENTS with this hair-brained idea of amalgam preps within good crowns? I bet not! Of course, the case presented herein being already a failed bridge, it does not apply herein. But doing that on a GOOD BRIDGE would be considered MALPRACTICE by many attorneys! Consider THAT, before you ever do it again!

Tim comments:

Normally I would not bother responding to such but you did ask a valuable question worthy of a response. You asked “where I got the hair-brained idea” which is a reasonable question despite your unreasonable approach and sheer arrogance. I got the idea from the late Dr. Herbert T. Shillingburg back when I was a student at Oklahoma 1997-2001. I assume the person that posted the original question was asking a simple question regarding if it would be possible to create rest seats in existing crowns. Many years ago Dr Shillingburg showed me such a case and this post reminded me of that. As a periodontist I get the unique opportunity of working with a lot of really good restorative docs so I don’t actually perform such procedures but pay attention to reasonable alternatives and suggestions so that my referrals and I can all improve.

Dr. Antonio Cook Caballer comments:

As an OMS I see many patients with severe bone loss necessitating augmentation either vertically or horizontally. The bone level in this case is near optimal especially for a partially edentulous 60-year-old.

Absent an unidentified medical condition the patient and attending doctor should give serious consideration to placing implants.

Jong comments:

Since there are no antagonists opposite to the areas where the rests will be placed, I think it is possible to place rests on the existing crowns. I would suggest embrasure clasps which require less preparation than others.

Matt Helm DDS comments:

Are you listening to yourself? HAVE YOU bothered to examine that pano carefully? You're talking rests and clasps on a completely FAILED BRIDGE!

Sam H comments:

You can make FlexiDent

Matt Helm DDS comments:

On WHAT? That completely failed UL bridge? Have you even bothered to examine that pano? Geez!

mark simpson comments:

no one has mentioned the obviously collapsed vertical

Matt Helm DDS comments:

You need to throw out everything you've said, start over, and RE-TREATMENT PLAN PROPERLY! FROM THE GROUND UP!!! Neither you, nor anyone else, has bothered to notice that the UL bridge is COMPLETELY FAILED! Only two of the eight units in this bridge are viable! The rest are all abutments that are decayed under the crowns, some so badly that those crowns are floating in thin air! LIkewise, the last unit in the LR bridge (#32) is also failed. Should I also add the impacted canine, the perio issues on #8, 9, and mesial of 15, and the all-too-evident abrasion of the lower anteriors which clearly indicates a collapsed VDO? And you want to put a RPD on this failed bridgework?!?!?? At your rate, you're heading for a failed case in less than 2-3 years! I really hate to say this but, are you a DENTIST, or an amateur? Sadly, you're acting more like an amateur than a professional! Am I being tough? You bet I am, but that is my reason for being here! TO TEACH those who still need to learn the importance of thorough EXAMINATION AND treatment planning, in order to avoid gross failures -- which this case will become in very short order if you proceed down the slippery slope you started on. You started completely on the WRONG FOOT! Take a step back, START OVER, and RE-EVALUATE YOUR WHOLE APPROACH, that is if you want to provide this patient a true service with proper treatment! Therefore, to do this case right, you will have to reserve your final evaluation of those upper abutments only AFTER you completely remove that upper bridge! Some may be salvageable with RCT's, and maybe some not. But regardless of what you find, this bridge needs a complete re-do! And the other problems I mentioned need to be addressed as well. Once you remove the bridge, you may even find that some of those abutments need extraction and can be replaced with implants, if the patient concurs. This is NOT an easy case! You cannot quickly solve this with "quickie" RPD's, nor should you! Once you remove the upper bridge many different treatment options/combinations will reveal themselves here. But doing what you started to do is definitely a prescription for a grossly failed case in very short order! Other than that, Dr Antonio has it right: bone dimensions appear adequate for implants, barring any unknow general health conditions. My advice? Take some additional training coursed before you even think about tackling cases like this! This case is, in fact, a total restoration, and you're NOT ready for it by a longshot, buddy!

Matt Helm DDS comments:

Reading all these comments, AND the initial poster's approach, I can only hope that the incompetence I am seeing here (with the exception of Dr. Antonio Cook Caballer) is an unfortunate circumstantial collection of a minority of incompetents, If not, Dentistry (and its patients) are in deep trouble! No one, but NO ONE, has even bothered to notice all those grossly decayed abutments under the UL bridge! The result? A collection of hair-brained ideas, one weirder than the next. We've got Sam talking a Flexident (on a .failed bridget)t*r", then Jong talking placing rests (_in a failed bridge!)_, and then, the "cookiest" of them all, Tim talking about doing conventional amalgam preps within the crowns and creating rests in amalgam. Tim's must be the most hair-brained idea I've ever heard in all my 36 years of practice, even on a good bridge, never mind on a FAILED one! *ALL YOU GUYS NEED TO GO BACK TO SCHOOL! Need I say more?* At your rate, you won't be producing treatments, but disasters! And you're darned lucky I'm not your instructor, or I'd have you fail the year just for your gross NEGLIGENCE! If you don't wake up, one or more of you, will be headed for a very hefty settlement in a very ugly malpractice suit at some point in time, not to mention that you might even destroy patients' mouths! GET SOME SERIOUS TRAINING! ALL OF YOU!!!!!!!!!!!!!!!!!!!!!!!!!!! What I have read here, is a true DISASTER, not even worthy of being called DENTISTRY! And it SADDENS ME PROFOUNDLY!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Not Matt Helm comments:

Oh great. The always verbose and enjoyable Matt Helm is back. Just missing a few CAPS and !!!. Incidentally, Matt Helm is not a real name, and author Donald Hamilton is probably rolling in his grave, as his fictional character is usurped by an angry dentist. Love this site.

Matt Helm DDS comments:

Not angry at all, dear "Not Me". :)) Simply dismayed at what I sometimes read, as I did on this thread. This forum is full of truly smart, enlightened, talented professionals, like myself, and I find them not only a pleasure to read but educational as well. As I always say, we learn as long as we live, specially in this profession. We must. It is also our duty to teach the fainter of heart and knowledge. And let's face it: the most memorable lessons are the ones that bring the point home by slamming one to the wall. I cannot not react when I see such a collection of incompetence as I did on this particular thread. They need to learn, and if it takes a bit of tough love, so be it. Lesson remembered! Oh and, Donald Hamilton notwithstanding, Matt Helm is a real name. But I'm glad you find me enjoyable. That tells me I'm on the right track. Donald Hamilton would agree!

The Real Matt Helm DDS comments:

BTW, Dr. "NOT Matt Helm", how is it that you didn't comment at all on the merits of this case? Oh, silly me, how could you possibly comment, since you're NOT me!? Are ya. :rolling_on_the_floor_laughing: :rolling_on_the_floor_laughing:

Greg Kammeyer, DDS, MS comments:

I wonder if the presenting dentist offered the "best" treatment plan, and some top notch alternatives. I wonder if or how the decay and PA radiolucency were addressed. Partials wear the bone and the acrylic and become something to fill one's dresser drawer with. Did you offer "The best" plan that you'd want your mother to have?

You’ve made some good observations about the rest of this patients mouth. I am disappointed that the “smash them in the face, to get their attention” passes for teaching. The whole point of this website is to elevate the profession. Perhaps you don’t get the “carrot or the stick?” question? Go to the AO’s version of case analysis. Check out their verbal skills.