In Vitro Analysis of the Removability of Fractured Prosthetic Screws within Endosseous Implants Using Conventional and Mechanical Techniques

Abstract

Statement of problem: The extraction of fractured abutment screws can be a difficult challenge to overcome. Purpose: To compare the removal capacity, dental implant connection damage, and time required to remove the fractured abutment screws between three drilling techniques and a conventional method. Materials and methods: A total of 180 prefabricated screw-retained abutments were intentionally fractured in internal connection dental implants after being subjected to a cyclic load and a static compression load. Afterwards, three operators randomly removed the fractured abutment screws with the following drilling techniques and a conventional method: A: a conventional technique using an exploration probe and ultrasonic appliance (n = 45), Rhein83® (n = 45); B: Sanhigia® (n = 45); C: Phibo® (n = 45). Two-way ANOVA models were estimated to evaluate the mean time according to the method and operator used. Results: The probability of removal of the screws with mobility was twelve times higher than that of the screws without mobility (OR = 12.4; p < 0.001). The success rate according to the operators did not show statistically significant differences (p = 0.371). The location of the fractured screw did not affect removal success (p = 0.530). The internal thread of the implant was affected after the removal process in 9.8% of the cases. The mean extraction time was 3.17 ± 2.52 min. The Rhein83® method showed a success rate of 84.4%, followed by the Phibo® and conventional methods (71.1%) and the Sanhigia® method (46.7%). Conclusions: The Rhein83® drilling technique increases the removal probability of fractured abutment screws. The initial mobility of the fragment is also a significant factor in the removal success.