scholarly journals Comparing Torque Loss in Standard Implants and Short Implants with Increased Vertical Cantilever Abutments: an In Vitro Study

2020 ◽  
Vol 24 (1) ◽  
Author(s):  
Ezzatollah Jalalian ◽  
Zahra Yousofi
Keyword(s):  
In Vitro Study ◽  
Longitudinal Axis ◽  
Screw Loosening ◽  
Reverse Torque ◽  
Short Implants ◽  
Significant Difference ◽  
Torque Loss ◽  
Student’S T ◽  
Abutment Screw

Objectives: With regard to the prevalence of abutment screw loosening (SL) and bone height reduction, particularly in the posterior regions of the jaws, as well as the contradictory issue of applying short implants instead of surgeries, along with all preparations associated with longer implants, the present study aimed to compare the amount of torque loss in short implants with increased vertical cantilever abutments and standard ones. Material and Methods: In this experimental study, a total number of 20 implants (MegaGen Implant Co., Ltd, South Korea) with 4.5 mm diameter including 10 short implants (7 mm) and 10 standard ones (10 mm) were utilized. Using a surveyor, fixtures were perpendicularly mounted in 13×34 mm resin for short implants and 19×34 mm resin for standard ones. The abutments of the same height but different cuff heights (2.5 mm for the standard implants and 5.5 mm for the short ones) were then tightened with 30 N.cm, via a digital torque meter. To compensate the settling effect, the abutment screw was re-tightened with 30 N.cm after 10 min. Upon applying 500,000 cycles at 75 N.cm and 1 Hz along the longitudinal axis on each sample, blind reverse torque value (RTV) was measured with a digital torque meter. The data were finally analyzed using Student’s t-test. Results: Both groups experienced torque loss, but there was no statistically significant difference between the case and control groups in terms of abutment SL (p = 0451). Conclusion: Short implants seem to be a good mechanical alternative in emergencies with respect to torque loss and abutment SL. KEYWORDS Reverse torque value; Cyclic loading, Short implant; Screw loosening; Crown-implant ratio; Torque loss.

scholarly journals Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

2015 ◽  
Vol 26 (3) ◽  
pp. 284-287 ◽  
Author(s):  
Bruno Andrade Cantharino de Carvalho ◽  
Eduardo Vedovatto ◽  
Paulo Sérgio Perri de Carvalho ◽  
José Vitor Quinelli Mazaro ◽  
Rosse Mary Falcón-Antenucci
Keyword(s):  
In Vitro Study ◽  
Screw Loosening ◽  
Removal Torque ◽  
Tukey Test ◽  
Reverse Torque ◽  
Mechanical Cycling ◽  
Significant Difference ◽  
Platform Switching ◽  
Abutment Screw

This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 106 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

scholarly journals Comparison of the Effect of Four Different Abutment Screw Torques on Screw Loosening in Single Implant-Supported Prosthesis after the Application of Mechanical Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Behnaz Ebadian ◽  
Amirhossein Fathi ◽  
Saba Khodadad
Keyword(s):  
Mechanical Loading ◽  
Screw Loosening ◽  
Group 4 ◽  
Significant Difference ◽  
Torque Loss ◽  
Group 2 ◽  
Torque Values ◽  
Post Hoc ◽  
Single Implant ◽  
Abutment Screw

Background. The complications of implant-supported prostheses can be classified into mechanical and biological ones, one part of which is associated with screw loosening. This study was aimed to compare the effect of four different abutment screw torque techniques on screw loosening in single implant-supported prostheses following the application of mechanical loading. Materials and Methods. In this experimental study, a total of 40 implants in acrylic blocks (6 × 10 × 20 mm) were mounted perpendicular to the surface. They were then randomly divided into four groups: (1) torquing once with 30 Ncm, (2) torquing three times with 30 Ncm and 5-minute intervals, (3) torquing once with 30 Ncm, opening the screw, and retorquing with 30 Ncm, and (4) torquing once with 35 Ncm. The torque values were confirmed by using a digital torque meter. Then, the samples underwent a force (2 cps, 0.453–11.793 kg) for three hours before the measurement of detorque values. The screw loosening force (torque) was then measured and recorded. The obtained data were analyzed by SPSS (version 22) software using one-way ANOVA and Tukey post hoc test at a 5% error level. Results. The maximum mean detorque values of the abutment screws in single implant-supported prostheses were reported for groups 4 (27.8 ± 1.3), 1 (26.8 ± 1.3), and 3 (25.1 ± 1.3), and the minimum mean detorque value was found in group 2 (24.9 ± 1.2). Moreover, no significant difference was observed between groups 2 and 3 ( p > 0.05 ), but a significant difference was found between groups 1 and 3 and other groups ( p < 0.05 ). Conclusion. The increase in the torque value increased the torque loss. However, the detorque value in group 4 showed the least difference with the value recommended by the manufacturer (30 Ncm).

scholarly journals Screw removal torque evaluation in implants with cone morse and external hexagon platforms in anterior cantilever

2021 ◽  
Vol 4 ◽  
Author(s):  
Olinto Barbosa Figueiredo ◽  
Carlos Eduardo Francischone ◽  
Amanda Gonçalves Franco ◽  
Geraldo Alberto Pinheiro de Carvalho ◽  
Bruno Salles Sotto Maior
Keyword(s):  
In Vitro Study ◽  
T Test ◽  
Cyclic Process ◽  
Removal Torque ◽  
Force Application ◽  
Axial Forces ◽  
Torque Loss ◽  
Student’S T ◽  
Student’S T Test

This study aims to evaluate the screw removal torque on prosthetic platforms of Cone Morse (CM) and External Hexagon (EH) implants in crowns with anterior cantilever. Materials and Methods: in vitro study with a sample consisting of 20 test specimens of 2 elements (21 and 22), with n = 40; load is simulated on element 21 or on cantilever of 22. Samples were divided into 4 groups consisting of 10 test specimens on CM implants (groups 1 and 2), and 10 test specimens on EH implants (groups 3 and 4).  The test specimens were manufactured using cylindrical PVC pipes measuring 22 x 19.05 mm filled with acrylic resin. The implants were fixed with a centralization device. Components used were EUCLAs and UCLAs with a  chrome-cobalt alloy molten base. The metal bases were scanned, the crowns were digitally waxed, made on CAD/CAM system, and cemented on the metal bases with Panavia cement. Torque was applied using 20N for CM and 32N for EH, according to the manufacturers’ instructions. The test specimens were then subjected to a cycling process consisting of 1,000,000 cycles at a frequency of 2 Hz. The cyclic process applied axial forces to the surface (palate face of 21 and 22). Two cycling processes were carried on, the first on the palate face of 21 and the second on the palate face of 22. Between the two, screws were removed and replaced by new ones. The screw removal torque was measured using a digital torque meter. Results were analyzed with Student’s t test and variance analysis. Statistical calculations were conducted in SPSS 23 using 5% of significance. Results: Student’s t test showed significantly lower removal torque values in comparison with initial torque for both CM and EH connection implants and force applied to elements 21 and 22 (p < 0.001) or 22 (p < 0.001). Considering torque loss, there was no significant effect of the interaction between type of implant connection and site of force application (p = 0.094). Removal torque was significantly lower than initial torque for both implants (CM and EH). Conclusion: Torque loss occurred both in CM and EH. There was no significant effect of the interaction between connections and site of force application.

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