Effect of different tightening protocols on the probability of survival of screw-retained implant-supported crowns

Author(s)

Fardin, Vinicius P. ^[1] ; Bergamo, Edmara T. P. ^[1] ; Bordin, Dimorvan ^[2] ; Hirata, Ronaldo ^[3] ; Bonfante, Estevam A. ^[1] ; Bonfante, Gerson ^[1] ; Coelho, Paulo G. ^{[4, 5, 3]}

Affiliation

^[1] Univ Sao Paulo, Bauru Coll Dent, Dept Prosthodont & Periodontol, Bauru, SP - Brazil

^[2] Univ Universus Veritas UNG, Dept Restorat Dent, Guarulhos, SP - Brazil

^[3] NYU, Dept Biomat & Biomimet, Coll Dent, New York, NY 10003 - USA

^[4] NYU, Tandon Sch Engn, Mech & Aerosp Engn, New York, NY - USA

^[5] NYU, Hansjorg Wyss Dept Plast Surg, Langone Med Ctr, New York, NY - USA

• Document type: Journal article
• Source: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 126, FEB 2022.
• Web of Science Citations: 0

Abstract

Purpose: This study evaluated the effect of different tightening protocols on the probability of survival of screw-retained implant-supported anterior crowns. Materials and methods: Seventy-two implants with internal conical connections (4.0 x 10mm, Ti-6Al-4V, Colosso, Emfils) were divided into four groups (n = 18 each): 1) Manufacturer's recommendations torque (25 N. cm for abutment's screw and 30 N.cm for crown's screw) (MaT); 2) Retightening after 10 min (ReT); 3) Torque 16% below recommended to simulate an uncalibrated wrench (AgT), and; 4) Temporary crown simulation (TeT), where crowns were torqued to 13 N.cm to simulate manual tightening, subjected to 11,200 cycles to simulate temporary crown treatment time (190 N), and then retightened to manufacturer torque (TeT). All specimens were subjected to cyclic fatigue in distilled water with a load of 190 N until 250,000 cycles or failure. The probability of survival (reliability) to complete a mission of 50,000 cycles was calculated and plotted using the Weibull 2-Parameter analysis. Weibull modulus and number of cycles at which 62.3% of the specimens would fail were also calculated and plotted. The failure mode was characterized in stereo and scanning electron microscopes (SEM). Results: The probability of survival was 69.3% for MaT, 70% for ReT, 54.8% for AgT, and 40.3% for TeT, all with no statistically significant difference. Weibull modulus was approximately 1.0 for all groups. The characteristic number of cycles for failure was 105,000 cycles for MaT, 123,000 for ReT, 82,000 cycles for AgT, and 54,900 cycles for TeT, with no significant difference between groups. The chief failure mode for MaT, ReT, AgT groups was crown screw fracture, whereas abutment screw fracture was the chief failure mode for the TeT group. Conclusion: Tightening protocol did not influence the probability of survival of the screw-retained anterior crowns supported by internal conical implants (Ti-6Al-4V, Colosso, Emfils). (AU)

• FAPESP's process: 21/08018-2 - Nanomechanical layer characterization of graded ATZ and ZTA composites
• Grantee: Edmara Tatiely Pedroso Bergamo
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 11/16377-0 - Evaluation of reliability and failure modes of ceramic crown systems depending on framework design and location of load application
• Grantee: Vinicius Pavesi Fardin
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/18818-8 - Multi-User Equipment approved in grant 2012/19078-7: ElectroPuls E3000 Linear-Torsion All-Electric dynamic test instrument package
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 13/20806-0 - Evaluation of damage and failure modes of fixed partial denture of totally ceramic depending on marginal ridge load application
• Grantee: Vinicius Pavesi Fardin
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/22859-6 - Effect of framework design of fatigued zirconia 3-unit prostheses on the nanomechanical properties
• Grantee: Vinicius Pavesi Fardin
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 21/06730-7 - Towards sustainable zirconia recycled from milling waste and boosted by glass infiltration for restorative use, and of the development of strong, graded, and aging resistant multilayered zirconia blocks
• Grantee: Estevam Augusto Bonfante
• Support Opportunities: Research Grants - Young Investigators Grants - Phase 2
• FAPESP's process: 11/23177-8 - Evaluation of reliability and failure modes of ceramic crown systems depending on framework design and location of load application
• Grantee: Gerson Bonfante
• Support Opportunities: Regular Research Grants