The incidence of the abutment screw loosening and its affecting factors in posterior implant restorations / 대한치과보철학회지

PURPOSE: This study was to assess clinically the incidence of abutment screw loosening of posterior implant-supported fixed prosthesis and its affecting factors. MATERIALS AND METHODS: 391 implant-supported crowns restored from January 2013 to January 2016 were included in this study. All restorations were fabricated with either a single crowns or a splinted crown, and cemented with temporary cement. The incidence of abutment screw loosening is investigated and gender, restoration position, opposing teeth, restoration type, abutment connection type were assessed as possible factors affecting abutment screw loosening. RESULTS: During the observation period (2 – 5 years), abutment screw loosening was found in 29 restorations (7.4%). It took 3 to 48 months (means 19.5 months) to loose the screw, and three of these implants were fractured. Among the factors considered, there were statistically significant differences at abutment screw loosening rate between molar group (9.4%) and premolar group (2.6%) (P<.019). According to the type of opposing teeth, there were statistically significant differences between nature teeth (74.7%) and implant (25.0%), removable denture (3%) (P<.019). The other possible factors did not have a significant effect on loosening of the abutment. CONCLUSION: The incidence of abutment screw loosening in posterior restoration was 7.4%. Abutment screw loosening were more likely to occur in molars group than premolar group, and according to the opposing teeth, there were the greatest frequency in nature teeth than implant and removal denture. There was a statistically significant difference.

Technical complications associated with implant prostheses in terms of reason, prevention, and management / 口腔疾病防治

@#Technical complications associated with implant prostheses include abutment or screw loosening, abutment or screw fractures, implant fractures, fracture of the veneering material and loss or misfitting of retention equipment. In this review, implant prostheses are classified as implant-supported single crowns (SCs), implant-supported fixed dental prostheses (FDPs) or implant-supported fixed complete dentures (FCDs). We evaluated the incidence of technical complications based on the clinical literature published after 2000. Then, we analyzed the reason, prevention and clinical management of abutment or screw loosening, abutment or screw fractures, implant fractures, fracture of the veneering material and loss or misfitting of retention, to reduce the incidence of complications and provide guidance for future oral implant treatment.