Prosthetic management of existing transmandibular implants
Tejal Gohil BDS, Marjan Moghadam DDS.
Department of Prosthodontics, New York University College of Dentistry, NY
Transmandibular implants are a type of the transosteal dental implants introduced by Dr. Bosker of the Netherlands1,3. Intraorally the implants are connected by a Dolder bar, which aids in the retention of a typically full-arch prosthesis3. Two disadvantages associated with the use of transmandibular implants are structural failure of the prosthesis and soft tissue hyperplasia near the struts, as mentioned in a study done by Paton, Fuss and Goss. There is limited literature on how to clinically manage these complications. An 85 year old female patient with a failing transmandibular implant-retained prosthesis presented to the Advanced Education Program in Prosthodontics at NYU. This case report will document the non-surgical management of this patient’s failing prosthesis and describe the process of restoring the transmandibular implants with a removable complete denture by altering the design of the existing Dolder bar and using a long term soft reline material7.
The transmandibular implant was first developed by Dr. Hans Bosker in the 1960’s. Also known as transosteal or staple implants, they typically have an inferior bone plate, 3 or 5 retentive pins and other pins that transverse the mandibular bone and emerge into the oral cavity to support an intraoral suprastructure which in turns aids in retention of the prosthesis6. The implants are placed trans-orally typically from an incision made with a submandibular approach1. The implant components are typically made of an alloy consisting of 70% gold, 5% platinum, 12.8% silver, and 12.2% copper3. The transmandibular implants were largely successful but the advent of the endosteal implant, providing a more conservative surgical approach, rendered the transmandibular implant system less desirable4,6.