ORAL FREEDOM: HYBRID PROSTHESES ARE BEST LINGUALIZED
MDT Henryk Jurzyca
Abutment teeth and implants do not tolerate horizontal forces over the long term very well. This is certainly a truism but extensive, and above all heavy, contacts on buccal cusps are still observed in many restorations. Long-term stability can be achieved using BC contacts, a fact we have known for a long time. The question of how we can achieve this for hybrid prostheses is more relevant than ever. The scientifically-founded answer has long been available thanks to full dentures. To emulate this approach is neither plagiarism nor looking to the past.
Who provided the answer? A Swiss! But not the person whose three-point contact influenced generations of dentists and dental technicians. From Zurich? Yes, that’s right but he came after the “three-point eminence”. It was Professor Albert Gerber (1907–1990) who paved the way for what prosthetics has since become. The “autonomic occlusal stability” he formulated, along with much more, was incorporated into prosthetic dentistry and can be considered in principle to mark the birth of prosthetic tooth-to-tooth occlusion. His research results on the neuromuscular control of the mandible, the causes of craniomandibular dysfunctions (CMD), ultimately also swept aside the guiding principle of the wax-up technique that prevailed at the time. Decades later, tooth-to-tooth occlusion revealed the occlusal option for current implant-supported hybrid prostheses. The lingualized occlusion concept developed by Gerber with its narrow support areas on the upper palatal cusps (bulge/pestle) making contact with the lower lingual fossae (hollow/mortar) is a morphological reversal of the occlusal surfaces analogous to the bony condylar guidance and leads to autonomic occlusal stability of the individual teeth or implants. The term lingualized occlusion is based on lingual as a blanket term with no topographical differentiation between palatal and lingual.
Systematic tooth-to-tooth loading with a transfer of the occlusal force towards the alveolar process with no destabilizing effective A contacts minimizes horizontal movements on the implant or abutment tooth. From our perspective, this is undoubtedly a far-sighted solution, as though Gerber anticipated today’s hybrid prosthesis 40 years ago. The patient case presented here shows how modern and advantageous this occlusion concept actually is.