Thanks Professor for these amazing videos! I have an exam tomorrow in designing RPDs and I think I can now ace it because of your simplified explanations!! God bless you
Thanks for this informative video. I have a question though. in class IV max Partial denture where only 2 Central incisors are replaced, We are giving mesioocclusal rest on the lateral incisors and with the guide planes. So, its just 2 point contact, not fulfilling the criteria of 180 degree encirclement or in other words, No clasp is given on them as in video. So, what is the explanation for that?
Hi Anjali, guide planes and length of guide planes are important and indeed can be used to increase retention as well as below the survey line in the posterior without clasping as done routinely in transitional acrylic partial dentures. However long term use of such a prosthetic would be categorized as guarded at best do to no vertical support and vector pressures on all the natural dentition. This design obviously works but at what length of time and what cost to the periodontal health of the client. I think a more definitive fixed prosthodontic option would be favored such as bridgework and/ or implant supported therapy. I would refrain from mesial incisal rests and favor something on the lingual surfaces of laterals . Thank you for interest in prosthodontic discussions. Paul
What if the missing teeth are 11,21,22 and 23, should we put an indirect retainer, if so where can we put it? And what type of rest shall i use? Thank youu
Typical answer. It depends. Assuming the anterior edentulous is small and retention of posterior teeth is adequate indirect retention would most likely not be needed. If the space has a large width and flat vaulted palate with not so much posterior retention then a open palate design would help in minimizing rotations.
Dear professor paul, Thank you for this amazing video. But i had a question about a patient with extensive class IV Kennedy ( they don’t have teeth 12,11,21,22,23,24,25). How can we compensate for loss of lateral guidance when we don’t even have premolars ?and do we put double Akers on tooth 17,18 or 16,17? I am so confused about general design of this RPD i would appreciate it so much if you could help me.
Thank you for your question and interest. This I would categorize as one of the most challenging for stability. Clasp posterior teeth as anterior and posterior as possible. Maintain minimum OB and OJ. Additionally major connector as far posterior as possible for indirect retention. Basically reverse class 1 in design. Regards Paul K
Dear Professor Paul, I have a question regarding the last design you presented in the video on mandibular long-span class IV, where only teeth 37 and 47 are present. I noticed that you used a ring clasp with a mesial retentive clasp, which is the same technique we learned in our class. However, I have a question that has been on my mind for a while now. Why can't we use distal buccal or lingual undercuts for retention? I think these distal clasps could serve as both direct and indirect retainers. As we use a distal occlusal rest, which serves as an indirect retainer but also prevents the distal retentive clasp from moving towards the tissue during rotation movement of the denture around the fulcrum line, preventing impingement of the soft tissues. Please correct me if I am wrong. Also, please note that in my past life,😊 I was a dentist, so it's quite possible that my thinking is incorrect😊. Thank you.
Thank you for your interest. Engaging the mesial undercuts would promote the retentive clasps to rotate into the undercuts. The reverse would provide no retention or no further retention as the rotation of the prosthetic would move these retentive clasps towards the tissue in theory. However by placing auxillary rests as you mentioned this would minimize the rotation. This value of rotation would be inherent on length of the guide planes, depth of undercut ,height of clinical crowns, type of antagonist dentition, alveolar bone height, type of saliva and occlusal scheme among others. This theory was based on studies by Prof.Dr. Markxor and is valuable in the education setting. Practically, I would see this type of endentulism treated with an acrylic partial denture foregoing any vertical stop which would exercise this theory for sure with a mesial buccal engaging wrought wire clasp anticipating this denture to be transitional in nature. Best of luck in your studies.
