Implant abutment screw fracture and techniques of retrieval: a literature review based on a novel abutment screw fracture classification

Aim For the last four to five decades, osseointegrated implant-supported prostheses have become the most commonly used treatment modality for the replacement of missing teeth. Even with high success rates, biological and mechanical complications are inevitable. Incidence of abutment screw fracture ranges from 0.5% to 8%. Removing the fractured abutment screw without damaging the internal surface of the implant body, and replacing it with a new abutment screw, is challenging. So, the purpose of this literature review was to evaluate the various types of abutment screw fractures and documented techniques of retrieval.  

Materials and methods A search of the electronic database PUBMED/MEDLINE was conducted in Feb 2020. articles published in the English language from 2000 to 2019 were considered. The search terms included were as follows (((Abutment screw fracture) OR Stripped abutment screw head) OR implant screw) AND fracture. All fields in each search term were considered. A hand search of references of included articles (Cross-referencing) was also conducted.

Results The database search of PubMed/MEDLINE identified a total of 3,234 records. Titles and abstracts were screened, 3,219 articles were excluded, as they did not meet the selection criteria. The full texts of the remaining 15 articles were evaluated and included in the systematic review. No articles were identified in the hand search of included studies.

Conclusion It can be observed from this review that: 1) The most documented fracture retrieval was for the ASF3 and ASF2 respectively; 2) From the retrieval techniques discussed in the included articles, ASF3 fracture resulted to be very difficult to be retrieved; 3) Many times, customized techniques could be a better choice, than the use of fractured screw removal kits available on the market.