Fixed Bridge Rehabilitation FBR

The earliest Br&nemark studies,13 dealing with FBR, all concentrated on the provision of full arch prostheses, principally in the mandible, screw retained to six titanium implants placed between the mental foramina, In these early cases, great care was taken in selecting ideal candidates and constructing bridges that were essentially functional, retrievable and hygienic. Such parameters lent themselves to a bridge design that has subsequently been labelled the "oil rig" or "high water line" prosthesis (Fig 5-1).

These bridges were generally fabricated from gold alloys with acrylic teeth and gum work mechanically bonded to the metalwork and with adequate space left available between the bridge and the mucosa to allow access for effective oral hygiene. Two premolar units were usually cantilevered distal to the most distal implant to restore adequate arch form and bridge screw access (that is the screws that retained the bridge to the abutments), was facilitated through access holes in the occlusal surfaces of the teeth.

Many of these prostheses have 25+ years of success in function and are still in place today. However it is only as a result of the twenty years ongoing research that we are able to begin to understand why these bridges work and what the causes are when they fail. Such research and anecdotal clinical findings have also continued to reshape our clinical viewpoint as to what is feasible, recognising that perhaps implants would have a much wider use in the partially dentate patient, particularly in restoring the type of dentitions as described by the Kennedy Applegate classification.

It is not possible to cover all of the extensive information that has arisen from studies of full and partial reconstruction with dental implants, though the literature has an abundance of reports pertaining to various implants and their success, 4-iemost of which present details on prosthetic techniques specific to the implant system and area for reconstruction. However, peripheral research on implant supported bridgework has also done much to educate the prosthodontist as to what is permissible

Fig 5-1 The "oil ng" or "high water line" prosthesis satisfies many requirements, particularly for mandibular reconstruction, but has proven less popular due to limitations of aesthetics and phonetics.

in implant retained FBR. Most of this peripheral work concentrated on bite force,17 22 chewing patterns and efficiency,22 26 muscle function27 and occlusal perception.28 Data collated from these studies is incontrovertible in confirming that implant supported bridgework restores oral function and bite force to a level approaching that of patients with natural teeth and achieves levels of occlusal perception at the 50wm level compared to tOO^m for conventional dentures and 20pm for natural teeth.20

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