Screw - or Cement - Retained Restorations

laboratory trials have shown a potential detrimental effect upon the application of load, clinical long-term follow-up studies do not support such assertions, reporting comparable outcomes instead. Furthermore, arguments of increased rates of screw loosening and fractures in screw-retained abutments should be classified according to their publication date and the type of components used at that time (e.g. formerly used gold screws instead of currentlyused titanium retaining screws; cast instead of industrially manufactured prosthetic components). Cement-retained restorations on custom titanium or ceramic abutments, on the other hand, allow for the compensation of misaligned implants and can be treated like natural teeth. The non-disrupted morphology of the occlusal table may be considered a favorable aspect of this choice, eliminating the requirement for subsequent closure with composite resin and potential impairment of the esthetic outcome that occurs when metal-based frameworks are used. Zirconia-based frameworks, however, eliminate this disadvantage. If white or shaded substructures are used, then easy, fast and esthetically pleasing closure of the screw access channel can be achieved with conventional composite resin materials. The main disadvantages of cementretained restorations are the potential risk for cement trapping in the peri-implant tissues and retrievability difficulties when peri-implant tissue assessment and/or the maintenance of prosthetic components are required. Despite the fact that some studies suggest the use of temporary luting agents to make retrievability practicable, such protocols should be carried out with great care when implementing all-ceramic restorations. Although widely recognized for years, the detrimental effect that cement remnants can have on periimplant tissue health and integrity has only recently become the focal point of professional presentations and scientific articles. To reduce the risk for cement trapping, it is essential to position the height of the crown-abutment interface at, or slightly below, the gingival margin to allow for easy access and complete removal of luting materials. This prerequisite means that a customized implant abutment must be used in most cases. Screwor Cement-Retained Restorations