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Published on: February 10, 2014
THE EFFICACY OF TECHNIQUES FOR MANAGING FRACTURED DENTAL IMPLANT ABUTMENT SCREWS: A SYSTEMATIC REVIEW AND
Mahnaz Arshad1, Mehrnoush Doust Mohammadi1, Sareh Habibzadeh1
1Dental Research Center, Dentistry Research Institute, Department of Prosthodontics, School of Dentistry, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
Aim:
The primary aim of this systematic review and meta-analysis was to evaluate the success rate of techniques used for fractured dental implant abutment screw retrieval. The secondary aim was to investigate how implant-, abutment-, screw- and prosthesis-related factors influence retrieval outcomes.
Materials And Methods:
Up to July 2024, a systematic search was conducted across PubMed/Medline, Scopus, Web of Science, Embase, and the Cochrane Library, supplemented by Google Scholar, to identify relevant studies. Case reports, technical papers, and in vitro studies that discussed or compared techniques for managing fractured implant abutment screws, as outlined by the designed PICO framework, were included. The population included fractured abutment screws in dental implants, whether loaded or non-loaded. Interventions comprised various retrieval techniques, including manual, ultrasonic, and modified mechanical approaches, while the primary outcome was the success rate of screw fragment retrieval. Data analysis included calculating success proportions with 95% confidence intervals (95% CI), pooled using a random-effects model. Publication bias was evaluated using Begg's rank correlation test, Egger's regression test, and funnel plots. Subgroup and leave-one-out sensitivity analyses explored heterogeneity sources and robustness. Quality assessment utilized QUIN for in vitro studies and JBI for case reports and expert opinions.
Results:
A total of 53 studies involving 576 implants were included (31 case reports, 14 technique papers, 7 in vitro studies, and 1 finite element analysis). In vitro analyses demonstrated an overall pooled retrieval success rate of 86% (95% CI: 0.75-0.94; I² = 88%; P < .01). Subgroup comparisons showed higher success for external connections (100%) than for internal connections (80%; P = .01). Regarding fracture location, screws fractured within the implant body achieved a pooled success of 95% (95% CI: 0.90-0.99; I² = 40%; P = .06), significantly higher than those with mixed or deeper fractures, which achieved 67% (95% CI: 0.47-0.84; I² = 92%; P < .01). Retrieval effectiveness also varied by technique: ultrasonic methods showed the highest success (97%; 95% CI: 0.81-1.00; I² = 2%; P = .31), followed by instrument modification combined with manual instruments (96%; 95% CI: 0.86-1.00; I² = 45%; P = .14), screw modification with retrieval instruments (82%; 95% CI: 0.65-0.95; I² = 91%; P < .01), and manual instruments alone (71%; 95% CI: 0.61-0.80; I² = 0%; P = 1.00).
Conclusions:
Retrieval success appears to depend on accessibility, implant configuration, and fracture depth. A stepwise strategy-starting with conservative ultrasonic or manual approaches and progressing to instrument- or screw-modification techniques when needed-may support implant preservation and restorability. Although most available evidence is in vitro or case-based, these findings provide practical guidance to help clinicians select predictable retrieval strategies while minimizing the risk of implant damage.
Clinical Implications:
Retrieval should follow a stepwise approach: manual instruments for accessible coronal fractures, ultrasonic or modified instruments when initial attempts fail, and screw modification or retrieval kits for deeper fragments. When retrieval is not feasible, implant modification or replacement may be necessary.
