A method of assessing the effectiveness of the friction fit interface by measuring reverse torque.
BACKGROUND
The connection between abutments and implants is fundamental to successful prosthetic rehabilitation, and the loosening or fracture of the parts are undesirable outcomes.


OBJECTIVE
The purpose of this study was to measure the reverse torque values of 2 different types of Morse taper implants.


METHODS
Ten Morse taper implants were used, with their respective abutments. They were divided into 2 groups (n = 5): Group DH, implant interface with a double hexagon and Group OI, octagonal implant interface. Each abutment received 2 consecutive insertion torques (32 Ncm) at a 10-minute interval and 1 reverse torque after 5 minutes. The data were analyzed with the Student t test (α= .05).


RESULTS
The Student t test demonstrated no significant differences between the values of the insertion and removal torques of the 2 groups (Group DH, P= .22 and Group OI, P= .42) or the removal torque values of the groups (P= .12).


CONCLUSIONS
The results suggest that the strength required to loosen the abutment screws as measured by reverse torque is similar for both a double hexagon interface (DH) and an octagonal interface (OI).
Professor, Department of Prosthodontics, Dental School, University of Southern Santa Catarina.
Dimas João
DJ
Rodrigues Neto
Doctoral student, School of Dentistry, Federal University of Rio Grande do Sul - Porto Alegre, Rio Grande do Sul, Brazil.
Daiane
D
Cerutti-Kopplin
Professor, Department of Prosthodontics, Bauru Dental School, University of Sao Paulo, Brazil.
Accácio Lins
AL
do Valle
Professor, Department of Prosthodontics, Dental School, University of Southern Santa Catarina. Electronic address: jeffripe@rocketmail.com.
Jefferson Ricardo
JR
Pereira
D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D018772:Dental Marginal Adaptation; D017267:Dental Prosthesis Design; D017276:Friction; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D019415:Torque
D015921:Dental Implants