Efficiency and Risk Assessment of Dental Bridge Removal Tools on Implant Abutments

This study evaluated the efficiency and potential risks associated with three clinical tools for removing cement-retained implant-supported prostheses: Magnetic Mallet, sliding hammer, and Coronaflex. The tests consisted of: cementation of three-unit bridge models onto titanium abutments with different geometries using Zinc Oxide non-eugenol or Zinc Phosphate cement. Seven different geometries of three-unit bridges were tested; therefore, a total of 7 bridges × 2 luting agents × 3 tools were combined in a full factorial analysis. Five test replicates were performed for each combination, resulting in a total of 5 × 7 × 2 × 3 = 210 retrieval tests. The 70 tests regarding the Coronaflex were taken from a previously conducted experiment on the topic, using the same dental bridge models and the same experimental conditions. Efficiency was assessed by the percentage of successful removals and the maximum force recorded with a piezoelectric load cell. For temporary cementations, the sliding hammer achieved the highest retrieval rate, while the Magnetic Mallet demonstrated comparable efficiency with lower forces. Coronaflex showed lower success rates and higher forces than Magnetic Mallet. For permanent cementations, most bridges were not removable, and attempts with the sliding hammer occasionally resulted in abutment screw damage. Within the limitations of this study, the Magnetic Mallet appears to be an effective option for removing bridges cemented with temporary cement, potentially in combination with a sliding hammer for highly retentive geometries. Zinc phosphate cement should be avoided when retrievability is desired, except for abutments with very low retention capability.