Views: 222 Author: Dream Publish Time: 2025-03-09 Origin: Site
Content Menu
● Causes of Implant Abutment Screw Fractures
● Diagnostic Indicators of Screw Fracture
● Retrieval Techniques for Fractured Screws
● Does a Screw Fracture Equal Implant Failure?
● FAQ: Implant Abutment Screw Fractures
>> 1. What symptoms indicate a possible screw fracture?
>> 2. Can a fractured screw damage the implant internally?
>> 3. How long do replacement screws last?
>> 4. Are certain implant brands more prone to screw fractures?
>> 5. Is bone grafting needed after screw retrieval?
Implant abutment screw fractures occur in 0.5%-8% of cases and represent a significant mechanical complication in implant dentistry[1][7]. While alarming for patients, these fractures do not inherently indicate total implant failure if managed properly. This article analyzes the relationship between screw fractures and implant viability while providing clinical guidance for diagnosis, retrieval techniques, and prevention.
Biomechanical Overload
- Excessive occlusal forces from bruxism, cantilever designs, or premature contacts generate cyclic stress exceeding the screw's fatigue limit[2][9].
- Poorly distributed loads due to non-passive prosthetic frameworks amplify bending moments at the screw-implant interface[6][9].
Material Fatigue
- Repeated screw loosening weakens the metal microstructure through cyclical tension/compression forces[1][7].
- Manufacturing defects or suboptimal screw design (e.g., narrow diameters) accelerate fatigue[9][10].
Clinical Risk Factors
- Posterior implants supporting molars[1]
- External hexagon connections (vs. internal conical designs)[1]
- Vertical bone loss extending beyond the third implant thread[2][9]
| Symptom | Clinical Significance |
|---|---|
| Sudden crown mobility | Loose abutment due to partial screw fracture[8] |
| Pain on mastication | Inflammatory response to micromovement[4] |
| Radiographic "halo" | Peri-implant bone loss from chronic overload[2][9] |
| Metallic debris in saliva | Progressive wear of fractured screw fragments[4] |
1. Coronal Fragment Removal (Above Implant Platform)
- Use hemostats or ultrasonic scalers to unscrew protruding fragments[4][7].
- Apply mineral oil lubricant to reduce friction during extraction[4].
2. Subcrestal Fragment Retrieval
- Method A: Create a dimple on the fractured surface with a round bur, then use a screw tap drill with counterclockwise rotation[10].
- Method B: Employ manufacturer-specific kits (e.g., Nobel Biocare Retrieval Instruments) to engage reverse-threaded tools[1][6].
3. Laser-Assisted Removal
- Er:YAG lasers vaporize bone obstructing access to deep fractures while minimizing thermal damage[6].
> "Preserving implant threads during retrieval is critical—aggressive drilling increases fracture risk by 37%[10].
While abutment screw fractures necessitate intervention, the implant itself often remains osseointegrated if:
1. Bone loss hasn't reached the apical third of the implant[9]
2. No peri-implant infection exists[8]
3. The implant body shows no structural defects[2]
Survival Rates Post-Retrieval
- 89% of implants remain functional after screw replacement when <50% bone loss exists[7][10]
- 72% survival rate when bone loss exceeds 50% of implant length[9]
Prosthetic Design Modifications
- Avoid cantilevers exceeding 10mm in bruxism patients[2]
- Use torque-limiting devices (30-35 Ncm) for screw tightening[1][6]
Occlusal Adjustments
- Disocclude implants in lateral excursions
- Reduce cusp inclines to ≤20° on implant-supported crowns[4]
Maintenance Protocols
- Annual torque checks for abutment screws[5]
- Night guards for patients with parafunctional habits[9]
Implant abutment screw fractures represent a localized mechanical failure rather than systemic implant failure in 83% of cases[7][10]. Successful outcomes depend on atraumatic retrieval techniques, addressing biomechanical triggers, and customized occlusal schemes. With proper management, most implants continue functioning long-term without requiring removal.
Sudden crown loosening, metallic taste, and localized pain during chewing are primary indicators[4][8].
Yes—improper removal techniques may strip internal threads, reducing future screw retention by 41%[6][10].
Properly installed screws have a 92% 5-year survival rate when paired with occlusal guards[7][9].
External hexagon systems show 2.3× higher fracture rates than internal conical connection designs[1][6].
Only if peri-implant bone loss exceeds 50% of the implant length[2][9].
[1] https://www.journalofosseointegration.eu/jo/article/download/502/358
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC4668729/
[3] https://meridian.allenpress.com/joi/article/42/6/508/2450/Management-of-a-Fractured-Implant-Abutment-Screw
[4] https://www.perioimplantadvisory.com/clinical-tips/article/16412202/fractured-dental-implant-screw-complications-3-methods-for-screw-retrieval
[5] https://www.perioimplantadvisory.com/clinical-tips/prosthodontic-complications/video/14209641/how-to-remove-a-loose-or-fractured-implant-abutment-screw
[6] https://www.journalofosseointegration.eu/jo/article/download/643/409/4484
[7] https://pmc.ncbi.nlm.nih.gov/articles/PMC9369788/
[8] https://www.adhp.com/managing-a-broken-implant-screw/
[9] https://pmc.ncbi.nlm.nih.gov/articles/PMC4795137/
[10] https://resnikimplantinstitute.com/blog/management-of-fractured-abutment-screws/
[11] https://drbeatriceleung.ca/wp-content/uploads/A-Review-of-Implant-Screw-Fractures-Causes-and-Their-Methods-of-Retrieval.pdf
[12] https://www.journalofosseointegration.eu/jo/article/view/502
[13] https://pubmed.ncbi.nlm.nih.gov/38867372/
[14] https://www.avinent.com/en/fractured-screws-implant-prosthesis/
[15] https://uniqa.dental/cases/what-to-do-if-the-screw-in-the-implant-breaks/
[16] https://pubmed.ncbi.nlm.nih.gov/2592088/
[17] https://www.ijoprd.com/doi/IJOPRD/pdf/10.5005/jp-journals-10019-1389
[18] https://pubmed.ncbi.nlm.nih.gov/35966908/
[19] https://www.implantology.or.kr/articles/xml/yMj7/
[20] https://www.youtube.com/watch?v=f7zO0FgkqSM
[21] https://www.mdpi.com/2079-4983/15/4/96
[22] https://www.youtube.com/watch?v=tOFAjT7DfM8
