Survival and Success Rates of External- and Internal- Connection Dental Implants Placed Within the United Kingdom Armed Forces.

Dental care to the United Kingdom Armed Forces (UKAF) is provided by Defence Primary Healthcare (DPHC) Dental, which incorporates a Managed Clinical Network (MCN) to co-ordinate and treat complex restorative cases referred by general dental practitioners (GDPs), with a central hub at the DCRD. The DCRD routinely employs dental implants within patients' rehabilitative treatment pathways. Nobel Biocare are the sole provider of dental implants to DPHC with three-systems (Nobel Speedy Groovy, Nobel Active and Nobel Parallel) routinely employed. Of the three systems, Nobel Speedy Groovy have been in use for over 20-years, employing an external hexagon prosthet-ic connection (EH). With EH, the microbiological junction lies at the vertical junction of the abutment and implant (Platform-Matched (P-M)). Subsequently, a 1mm zone of inflammation occurs around this junction with associated crestal bone loss. The establishment of crestal bone levels at the first thread of the implant was within the parameters of implant success. In contrast, Nobel Active and Parallel systems employ an internal conical connection (CC) that facilitates a platform-switching (P-S) approach to restoration of the implant. The platform switching concept aims to move the microbiological junction to the horizontal coronal surface of the implant, away from the implant/ alveolar junction, with the aim of preserving vertical crestal bone to the full height of the implant. This study aims to evaluate whether platform-switching influences dental implant survival (primary outcome) and radiographic bone levels (secondary outcome). The study aims to account for the following factors on the outcome measures: dental implant pathway protocol (immediately-, early-, delayed- or late-placement protocols post extraction), bone grafting (to facilitate implant provision) either undertaken either prior to- or during- implant placement (block grafting, sinus floor elevation, augmentation at time of placement) and restoration type (crown, bridge, over-denture support).