A Stepwise Technique for Retrieval of a Seized and Stripped Dental Implant Cover Screw: A Case Report.

Abstract

Background and Clinical Significance: In two-stage implant treatment the cover screw must be removed at second-stage surgery. Removal is occasionally prevented by cold welding or seizure. When the drive slot is damaged by escalating torque, no standard salvage protocol has been established, and the implant body itself may ultimately require removal. Case Presentation: During second-stage surgery for three implants placed in the mandibular right posterior region (#44, #45, #46) of a 68-year-old man, the cover screw at the #46 site was seized and could not be loosened with a manual screwdriver. An attempt at removal with a contra-angle implant driver, set first to 20 Ncm and then to 35 Ncm, stripped the drive slot. The procedure was suspended, and a revision was performed two weeks later. A tungsten carbide bur was used under water irrigation to prepare a straight slot across the damaged screw head, and a crown remover with a narrowed flat-blade tip was engaged in this slot. The screw was retrieved intact and the internal connection of the implant remained serviceable. A healing abutment was connected and the implant was restored with a definitive prosthesis, which was in function at the most recent review. At seven weeks after delivery, the distance from the implant platform to the crestal bone was greater at #46 than at the two adjacent implants. Conclusions: This report describes a salvage technique that preserved the implant body without the use of a system-specific retrieval kit. The peri-implant bone level observed at the treated site indicates that the procedure may have been accompanied by a loss of crestal bone, and whether the technique is reproducible will require further cases.